阅读说明：本技术 一种可回收利用副产物的生产氯化钾的方法和系统 (Method and system for producing potassium chloride by recycling byproducts ) 是由 李小松 王兴富 谢康民 王石 黄龙 俞秋平 赵元海 张振杰 田红斌 张生太 任红 于 2019-03-06 设计创作，主要内容包括：一种可回收利用副产物的生产氯化钾的系统,包括,原矿处理系统1、调浆系统2、浮选系统3、低钠浓缩及脱卤系统4、冷结晶及粗钾筛分系统5、粗钾浓缩及脱卤系统6,精钾洗涤及脱卤系统7,还包括溢流液和滤液处理系统8,所述溢流液和滤液处理系统8用于回收处理所述第一溢流液、第三溢流液、第五溢流液和第一滤液。本发明一方面增加了氯化钾的产率,另一方面节约了成本。本发明在原矿浓密机12、浮选机32、低钠浓密机41等设备的多个并联,调浆罐22统一调浆、分散分配等方式,使得对物料的处理浓度统一的同时,各并联设备之间互成备用关系,即使某个设备故障或者需要检修,不影响整体工艺的运行。(The system for producing potassium chloride by recycling byproducts comprises a raw ore treatment system 1, a size mixing system 2, a flotation system 3, a low-sodium concentration and dehalogenation system 4, a cold crystallization and crude potassium screening system 5, a crude potassium concentration and dehalogenation system 6, a fine potassium washing and dehalogenation system 7 and an overflow liquid and filtrate treatment system 8, wherein the overflow liquid and filtrate treatment system 8 is used for recycling the first overflow liquid, the third overflow liquid, the fifth overflow liquid and the first filtrate. The invention increases the yield of potassium chloride on one hand and saves the cost on the other hand. In the invention, a plurality of devices such as the raw ore thickener 12, the flotation machine 32, the low-sodium thickener 41 and the like are connected in parallel, and the pulp mixing tank 22 adopts uniform pulp mixing, dispersing distribution and other modes, so that the treatment concentration of materials is uniform, and meanwhile, the parallel devices mutually form a standby relation, and even if a certain device fails or needs to be overhauled, the operation of the whole process is not influenced.)

1. A system for producing potassium chloride by recycling byproducts comprises a raw ore treatment system (1), a size mixing system (2), a flotation system (3), a low-sodium concentration and dehalogenation system (4), a cold crystallization and crude potassium screening system (5), a crude potassium concentration and dehalogenation system (6), a refined potassium washing and dehalogenation system (7), and an overflow liquid and filtrate treatment system (8),

the raw ore treatment system (1) is used for screening and concentrating carnallite pulp to obtain first underflow pulp and first overflow liquid;

the size mixing system (2) is connected with the raw ore processing system (1) and is used for mixing a flotation reagent with the first underflow slurry to obtain size mixing slurry;

the flotation system (3) is used for carrying out flotation operation on the size mixing slurry to obtain tail salt and low-sodium carnallite slurry;

the low-sodium concentration and dehalogenation system (4) is connected with the flotation system (3) and is used for concentrating the low-sodium carnallite slurry and removing brine to obtain a second overflow liquid, a first filtrate and low-sodium carnallite ore with the moisture content of less than or equal to 10%;

the cold crystallization and crude potassium screening system (5) is connected with the low-sodium concentration and dehalogenation system (4) and is used for decomposing and crystallizing low-sodium carnallite ore with the moisture content of less than or equal to 10% and screening to obtain a third overflow liquid, crude potassium oversize products and crude potassium undersize products;

the crude potassium concentration and dehalogenation system (6) is connected with the cold crystallization and crude potassium screening system (5) and is used for concentrating and dehalogenating the undersize product of the crude potassium to obtain a fourth overflow liquid, a second filtrate and crude potassium ore with the moisture content of less than or equal to 10%;

the refined potassium washing and dehalogenation system (7) is connected with the crude potassium concentration and dehalogenation system (6) and is used for washing and dehalogenating the crude potassium ore with the moisture content of less than or equal to 10% to obtain a third filtrate and refined potassium ore;

the overflow liquid and filtrate treatment system (8) is used for recovering and treating the first overflow liquid, the third overflow liquid, the fifth overflow liquid and the first filtrate.

2. System according to claim 1, wherein the overflow and filtrate treatment system (8) comprises a first treatment system (81), a second treatment system (82), a third treatment system (83),

the first treatment system (81) is respectively connected with the raw ore treatment system (1) and the flotation system (3) and is used for receiving a first overflow liquid from the raw ore treatment system (1), receiving flotation tail salt from the flotation system (3), and discharging the first overflow liquid and the flotation tail salt after size mixing;

the second treatment system (82) is respectively connected with the cold crystallization and crude potassium screening system (5) and the refined potassium washing and dehalogenation system (7) and is used for receiving a third overflow liquid from the cold crystallization and crude potassium screening system (5) and a fifth overflow liquid from the refined potassium washing and dehalogenation system (7), and the fifth overflow liquid is adjusted by fresh water and then is conveyed to the cold crystallization and crude potassium screening system (5) to be used as a decomposition mother liquid;

and the third treatment system (83) is connected with the low-sodium concentration and dehalogenation system (4) and is used for receiving the first filtrate, concentrating and filtering the first filtrate and recovering carnallite.

3. The system of claim 1, wherein the first treatment system (81) further comprises a primary scavenger slot (811), a secondary scavenger slot (812), a storage tank (813),

the primary scavenging groove (811) is connected with the flotation system and used for receiving flotation tail salt and performing primary scavenging to obtain primary scavenging foam and primary scavenging underflow;

the secondary scavenging groove (812) is connected with the primary scavenging groove (811) and is used for receiving the primary scavenging underflow and performing secondary scavenging to obtain secondary scavenging foam and secondary scavenging underflow;

the primary scavenging chute (811) is connected with the tailing pond and is used for conveying the primary scavenging foam to the tailing pond;

the secondary scavenger sump (812) is connected to the storage tank (813) for conveying the secondary scavenger underflow to the storage tank (813);

the secondary scavenger tank (812) is connected to the low sodium concentration and dehalogenation system for conveying the secondary scavenger underflow to the low sodium concentration and dehalogenation system.

4. The system according to claim 1, wherein the low sodium concentration and dehalogenation system (4) is connected to the flotation system (3) for conveying the second overflow liquid to the flotation system (3) for adjusting the concentration of the slurried slurry.

5. The system according to claim 1, wherein the crude potassium concentration and dehalogenation system (6) is connected to the raw ore treatment system (1) for sending the fourth overflow to the raw ore treatment system (1) for concentration utilization.

6. The system of claim 1, wherein the fine potassium wash and dehalogenation system (7) comprises a repulping wash tank (71), a fine potassium thickener (72), and a fine potassium centrifuge (73),

the repulping washing tank (71) is one or more and is used for receiving the crude potassium ore with the moisture content less than or equal to 10% and washing to obtain repulping washing slurry;

one or more refined potassium thickeners (72) are matched with the repulping and washing tank and used for concentrating the repulping and washing slurry to obtain fifth underflow slurry;

one or more fine potassium centrifuges (73) are matched with the fine potassium thickener (72) and are used for dehalogenating the fifth underflow slurry to obtain fine potassium ore and third filtrate;

the moisture content of the refined potassium ore is less than or equal to 10 percent.

7. A method for producing potassium chloride capable of recycling byproducts comprises,

a first step (S1) of screening and concentrating the carnallite pulp to obtain a first underflow pulp and a first overflow liquor;

a second step (S2) of mixing a flotation reagent with the first underflow slurry to obtain a size-mixed slurry;

a third step (S3) of subjecting the size-mixed slurry to flotation operation to obtain tail salt and low-sodium carnallite slurry;

a fourth step (S4) of concentrating the low-sodium carnallite slurry and removing brine to obtain a second overflow liquid, a first filtrate and low-sodium carnallite ore with the moisture content less than or equal to 10%;

a fifth step (S5) of decomposing and crystallizing the low-sodium carnallite ore with the moisture content less than or equal to 10%, and sieving to obtain a third overflow liquid, a coarse potassium oversize product and a coarse potassium undersize product;

a sixth step (S6) of concentrating and dehalogenating the undersize of the crude potassium to obtain a fourth overflow liquid, a second filtrate and crude potassium ore with the moisture content less than or equal to 10%;

a seventh step (S7) of washing and dehalogenating the crude potassium ore with the moisture content of less than or equal to 10% to obtain a third filtrate and a refined potassium ore;

an eighth step (S8) of recovering and treating the first overflow liquid, the third overflow liquid, the fifth overflow liquid, and the first filtrate.

8. The method according to claim 7, wherein the eighth step (S8) includes,

mixing the first overflow liquid with the flotation tail salt, and discharging;

receiving the third overflow liquid and the fifth overflow liquid, and using the third overflow liquid and the fifth overflow liquid as decomposition mother liquid of a crystallization process after fresh water regulation;

and receiving the first filtrate, concentrating and filtering the first filtrate, and recovering the carnallite.

9. The method of claim 8, further comprising subjecting the flotation tailings to primary scavenging, resulting in a primary scavenged froth and a primary scavenged underflow;

performing secondary scavenging on the primary scavenging underflow to obtain secondary scavenging foam and secondary scavenging underflow;

mixing the primary scavenging foam and the first overflow liquid, and conveying the mixture to a tail salt pond;

the secondary scavenger bottom stream is conveyed to the low sodium concentration and dehalogenation system.

10. The method of claim 7, wherein the second overflow liquid is used to adjust the concentration of the sized slurry.

Technical Field

The invention relates to the field of potassium chloride production, in particular to a method and a system for producing potassium chloride, which can recycle byproducts.

Background

The existing method for producing potassium chloride by using salt lake brine mainly comprises a cold crystallization-direct flotation process, a hot melting crystallization process, a reverse flotation-cold crystallization process, a brine blending process and the like or the combination of the processes. The reverse flotation-cold crystallization process is widely used, but the process has high requirements on the quality of raw material carnallite, is suitable for producing carnallite ores in salt fields, has large input amount and large energy consumption, and the grade of final product potassium chloride can only reach about 95 percent.

Meanwhile, in the whole production process, the potassium chloride contained in the generated by-products is not sufficient in the aspect of recovery treatment, so that a large amount of potassium chloride is discharged along with tail salt, and the potassium resource is wasted.

In addition, on the whole production line, because certain equipment goes wrong, the materials can be accumulated, serious shutdown and maintenance are even needed for the whole production line, and the improvement of the production efficiency is not facilitated.

Therefore, there is a need to further improve and enhance the related production system and process, and the by-products in the potash fertilizer production are combined by in-system utilization and out-system utilization, so as to extract the potassium chloride in the raw materials as much as possible, increase the yield and efficiency of the potash fertilizer, and in addition, improve the connection mode and combination mode of each equipment, so as to facilitate the maintenance of continuous production, and not influence the overall process due to individual equipment failure.

Disclosure of Invention

The invention solves the problem of providing a method and a system for producing potassium chloride, which can recycle by-products.

The invention provides a system for producing potassium chloride by recycling byproducts, which comprises a raw ore processing system 1, a size mixing system 2, a flotation system 3, a low-sodium concentration and dehalogenation system 4, a cold crystallization and crude potassium screening system 5, a crude potassium concentration and dehalogenation system 6, a fine potassium washing and dehalogenation system 7 and an overflow liquid and filtrate processing system 8, wherein the raw ore processing system 1 is used for screening and concentrating carnallite pulp to obtain first underflow pulp and first overflow liquid; the size mixing system 2 is connected with the raw ore processing system 1 and is used for mixing a flotation reagent with the first underflow slurry to obtain size mixing slurry; the flotation system 3 is used for carrying out flotation operation on the size mixing slurry to obtain tail salt and low-sodium carnallite slurry; the low-sodium concentration and dehalogenation system 4 is connected with the flotation system 3 and is used for concentrating the low-sodium carnallite slurry and removing brine to obtain a second overflow liquid, a first filtrate and low-sodium carnallite ore with the moisture content of less than or equal to 10%; the cold crystallization and crude potassium screening system 5 is connected with the low-sodium concentration and dehalogenation system 4 and is used for decomposing and crystallizing low-sodium carnallite ore with the moisture content of less than or equal to 10% and screening to obtain a third overflow liquid, crude potassium oversize products and crude potassium undersize products; the crude potassium concentration and dehalogenation system 6 is connected with the cold crystallization and crude potassium screening system 5 and is used for concentrating and dehalogenating the undersize of the crude potassium to obtain a fourth overflow liquid, a second filtrate and crude potassium ore with the moisture content of less than or equal to 10%; the refined potassium washing and dehalogenation system 7 is connected with the crude potassium concentration and dehalogenation system 6 and is used for washing and dehalogenating the crude potassium ore with the moisture content of less than or equal to 10% to obtain a third filtrate and refined potassium ore; and the overflow liquid and filtrate treatment system 8 is used for recovering and treating the first overflow liquid, the third overflow liquid, the fifth overflow liquid and the first filtrate.

According to an embodiment of the present invention, the overflow liquid and filtrate processing system 8 comprises a first processing system 81, a second processing system 82, and a third processing system 83, wherein the first processing system 81 is connected to the raw ore processing system 1 and the flotation system 3, respectively, and is configured to receive a first overflow liquid from the raw ore processing system 1, receive flotation tail salt from the flotation system 3, and discharge the first overflow liquid and the flotation tail salt after size mixing; the second treatment system 82 is connected with the cold crystallization and crude potassium screening system 5 and the refined potassium washing and dehalogenation system 7 respectively, and is used for receiving a third overflow liquid from the cold crystallization and crude potassium screening system 5, receiving a fifth overflow liquid from the refined potassium washing and dehalogenation system 7, adjusting the fifth overflow liquid with fresh water, and conveying the fifth overflow liquid to the cold crystallization and crude potassium screening system 5 to be used as a decomposition mother liquid; the third treatment system 83 is connected to the low-sodium concentration and dehalogenation system 4, and is configured to receive the first filtrate, concentrate and filter the first filtrate, and recover carnallite.

According to one embodiment of the invention, the first treatment system (81) further comprises a primary scavenging tank 811, a secondary scavenging tank 812, a storage tank 813, wherein the primary scavenging tank 811 is connected with the flotation system and is used for receiving flotation tail salt and performing primary scavenging to obtain primary scavenging foam and primary scavenging underflow; the secondary scavenging slot 812 is connected with the primary scavenging slot 811 and is used for receiving the primary scavenging underflow and performing secondary scavenging to obtain secondary scavenging foam and secondary scavenging underflow; the primary scavenging groove 811 is connected with the tail salt pond and is used for conveying the primary scavenging foam to the tail salt pond; the secondary scavenger sump 812 is connected to the storage tank 813 for transferring the secondary scavenger underflow to the storage tank 813; the secondary scavenger tank 812 is connected to the low sodium concentration and dehalogenation system for conveying the secondary scavenger underflow to the low sodium concentration and dehalogenation system.

According to one embodiment of the invention, the low-sodium concentration and dehalogenation system 4 is connected to the flotation system 3 for delivering the second overflow liquid to the flotation system 3 for adjusting the concentration of the slurried slurry.

According to one embodiment of the present invention, the crude potassium concentration and dehalogenation system 6 is connected to the raw ore processing system 1 for sending the fourth overflow liquid to the raw ore processing system 1 for concentration utilization.

According to one embodiment of the invention, the raw ore processing system 1 comprises a carnallite screening machine 11 and a raw ore thickener 12, wherein the carnallite screening machine 11 is used for screening impurities and large-particle salt in carnallite pulp to obtain undersize products; the raw ore thickener 12 is connected to the carnallite screening machine 11, and is configured to concentrate the undersize product to obtain a first overflow liquid and a first underflow ore pulp, so that the first underflow ore pulp has a solid mass content: 30-45%, and one or more raw ore thickeners 12.

According to one embodiment of the present invention, the size mixing system 2 comprises a slurry distribution tank 21 and a size mixing tank 22, the slurry distribution tank 21 comprising a plurality of raw ore thickeners 12 interface for connecting with a plurality of raw ore thickeners 12, receiving the first underflow slurry, mixing the first underflow slurry with a flotation agent, and distributing the first underflow slurry and the flotation agent to the size mixing tank 22; the slurry mixing tank 22 is connected to the slurry distribution tank 21, and is configured to uniformly mix the first underflow slurry and the flotation reagent to obtain a slurry mixture.

According to one embodiment of the invention, the flotation system 3 comprises a flotation distribution tank 31 and a flotation machine 32, wherein the flotation distribution tank 31 is connected with the size mixing system 2 and is used for receiving the size mixing slurry and adjusting the concentration of the size mixing slurry by adding an adjusting mother liquor to obtain an adjusted slurry; the solid mass content of the adjusting slurry is 20-25%; the adjusting mother liquor refers to a liquid phase with the same component as the slurry mother liquor; the flotation machine 32 is connected with the flotation distribution tank 31 and is used for performing rough concentration, fine concentration and scavenging on the adjusted slurry to obtain tail salt and low-sodium carnallite pulp; the flotation machine 32 is one or more.

According to one embodiment of the present invention, the low sodium concentration and dehalogenation system 4 comprises a low sodium thickener 41, a low sodium centrifuge distribution tank 42 and a low sodium centrifuge 43, the low sodium thickener 41 is configured to receive a low sodium carnallite slurry and concentrate the low sodium carnallite slurry to obtain a second underflow slurry and a second overflow liquid; the mass content of the second underflow ore pulp solid is 40-45%; one or more low-sodium thickeners 41; the low sodium centrifuge distribution tank 42 is connected to the low sodium thickener 41 for receiving the second underflow slurry and distributing the second underflow slurry to a low sodium centrifuge 43; the low-sodium centrifuges 43 are connected to the distribution tank 42 of the low-sodium centrifuges, and are used for dehalogenating the second underflow slurry to obtain a first filtrate and low-sodium carnallite ore with moisture content less than or equal to 10%.

According to one embodiment of the present invention, the cold crystallization and crude potassium screening system 5 comprises a crystallizer 51 and a crude potassium screening machine 52, wherein one or more of the crystallizers 51 are used for receiving the low sodium carnallite ore with moisture content less than or equal to 10% and decomposing and crystallizing to obtain a third underflow ore pulp and a third overflow liquid; the third underflow slurry solid mass content is 15-30%; the coarse potassium screening machine 52 is connected to the crystallizer 51, and is configured to screen the third underflow slurry to obtain coarse potassium oversize products and coarse potassium undersize products.

According to one embodiment of the present invention, the crude potassium concentration and dehalogenation system 6 comprises a crude potassium thickener 61, a crude potassium centrifuge distribution tank 62 and a crude potassium centrifuge 63, wherein the crude potassium thickener 61 is one or more for receiving and concentrating the crude potassium undersize to obtain a fourth overflow liquid and a fourth underflow pulp; the solid mass content of the fourth underflow slurry is 40-45%; the crude potassium centrifuge distribution tank 62 is connected to the crude potassium thickener 61, and is configured to receive the fourth underflow slurry and distribute the fourth underflow slurry to each crude potassium centrifuge 63; and one or more crude potassium centrifuges 63 are connected with the crude potassium centrifuge distribution tank 62 and used for dehalogenating the fourth underflow slurry to obtain a second filtrate and crude potassium ore with the moisture content of less than or equal to 10%.

According to one embodiment of the invention, the coarse potassium centrifuge 63 is connected to the coarse potassium thickener 61 for transporting the second filtrate to the coarse potassium thickener 61 for recycling.

According to one embodiment of the invention, the fine potassium washing and dehalogenation system 7 comprises a repulping washing tank 71, a fine potassium thickener 72 and a fine potassium centrifuge 73, wherein the repulping washing tank 71 is one or more than one and is used for receiving and washing the crude potassium ore with the moisture content of less than or equal to 10% to obtain repulping washing slurry; one or more fine potassium thickeners 72 are matched with the repulping and washing tank and used for concentrating the repulping and washing slurry to obtain fifth underflow slurry; one or more fine potassium centrifuges 73 are matched with the fine potassium thickener 72 and used for dehalogenating the fifth underflow slurry to obtain fine potassium ore and third filtrate; the moisture content of the refined potassium ore is less than or equal to 10 percent.

According to one embodiment of the invention, the fine potassium thickener 72 is connected to the reslurry wash tank for adjusting the concentration of the crude potassium ore with a moisture content of 10% or less using the fifth underflow slurry. The fine potassium thickener 72 is connected to the fine potassium centrifuge 73, and is configured to recycle the third filtrate to the fine potassium thickener 72 for concentration.

According to an aspect of the present invention, there is provided a method for producing potassium chloride capable of recycling byproducts, comprising a first step S1 of screening and concentrating a carnallite pulp to obtain a first underflow pulp and a first overflow liquid; a second step S2 of mixing a flotation reagent with the first underflow slurry to obtain a size mixing slurry; step S3, carrying out flotation operation on the size mixing slurry to obtain tail salt and low-sodium carnallite slurry; a fourth step S4, concentrating the low-sodium carnallite slurry and removing brine to obtain a second overflow liquid, a first filtrate and low-sodium carnallite ore with the moisture content less than or equal to 10%; a fifth step S5, decomposing and crystallizing the low-sodium carnallite ore with the moisture content less than or equal to 10%, and sieving to obtain a third overflow liquid, a coarse potassium oversize product and a coarse potassium undersize product; a sixth step S6, concentrating and dehalogenating the coarse potassium undersize to obtain a fourth overflow liquid, a second filtrate and coarse potassium ore with the moisture content less than or equal to 10%; a seventh step S7, washing and dehalogenating the crude potassium ore with the moisture content less than or equal to 10% to obtain a third filtrate and refined potassium ore; an eighth step S8 of recovering and processing the first overflow liquid, the third overflow liquid, the fifth overflow liquid, and the first filtrate.

According to an embodiment of the present invention, the eighth step S8 includes discharging the first overflow liquid after being size-mixed with the flotation tail salt; receiving the third overflow liquid and the fifth overflow liquid, and using the third overflow liquid and the fifth overflow liquid as decomposition mother liquid of a crystallization process after fresh water regulation; and receiving the first filtrate, concentrating and filtering the first filtrate, and recovering the carnallite.

According to one embodiment of the invention, the method further comprises the steps of subjecting the flotation tail salt to primary scavenging to obtain primary scavenging foam and primary scavenging underflow; performing secondary scavenging on the primary scavenging underflow to obtain secondary scavenging foam and secondary scavenging underflow; mixing the primary scavenging foam and the first overflow liquid, and conveying the mixture to a tail salt pond; the secondary scavenger bottom stream is conveyed to the low sodium concentration and dehalogenation system.

According to one embodiment of the invention, the second overflow liquid is used for adjusting the concentration of the size-mixed slurry.

According to one embodiment of the invention, the fourth overflow is used for conditioning a carnallite slurry.

According to one embodiment of the present invention, the first step S1 includes screening out impurities and large particle salts in the carnallite slurry to obtain undersize product; concentrating the undersize product to obtain a first overflow liquid and a first underflow pulp, and ensuring the solid mass content of the first underflow pulp to be: 30% -45%; the solid mass content of the carnallite pulp is more than or equal to 25 percent.

According to one embodiment of the invention, the second step S2 includes mixing the first underflow slurry with a flotation reagent and distributing the first underflow slurry and the flotation reagent; and uniformly mixing the first underflow slurry and the flotation reagent to obtain size mixing slurry.

According to an embodiment of the present invention, the third step S3 includes adjusting the concentration of the conditioned slurry by adding an adjusting mother liquor to obtain an adjusted slurry; the solid mass content of the adjusting slurry is 20-25%; the adjusting mother liquor refers to a liquid phase with the same component as the slurry mother liquor; and carrying out rough concentration, fine concentration and scavenging on the adjusted slurry to obtain tail salt and low-sodium carnallite pulp.

According to an embodiment of the present invention, the fourth step S4 includes concentrating the low sodium carnallite pulp to obtain a second underflow pulp and a second overflow liquid; the mass content of the second underflow ore pulp solid is 40-45%; distributing the second underflow slurry; and dehalogenating the second underflow ore pulp to obtain a first filtrate and low-sodium carnallite ore with the moisture content of less than or equal to 10%.

According to an embodiment of the present invention, the fifth step S5 includes mixing the low-sodiumniosulgite ore with moisture content less than or equal to 10% with decomposition mother liquor, performing controlled-speed decomposition crystallization to obtain a third underflow slurry and a third overflow solution; the third underflow slurry solid mass content is 15-30%; and screening the third underflow slurry to obtain coarse potassium oversize products and coarse potassium undersize products.

According to one embodiment of the invention, the sixth step S6 includes concentrating the potassium rejects to obtain a fourth overflow and a fourth underflow slurry; the solid mass content of the fourth underflow slurry is 40-45%; distributing the fourth underflow slurry; and dehalogenating the fourth underflow slurry to obtain a second filtrate and crude potassium ore with the moisture content of less than or equal to 10%.

According to one embodiment of the invention, the second filtrate is sent to a process for concentrating the undersize of crude potassium for recycling.

According to an embodiment of the invention, the seventh step S7 includes washing the crude potassium ore with moisture content less than or equal to 10% to obtain reslurry washing slurry; concentrating the repulped and washed slurry to obtain fifth underflow slurry; dehalogenating the fifth underflow slurry to obtain fine potassium ore and third filtrate; the moisture content of the refined potassium ore is less than or equal to 10 percent.

According to one embodiment of the invention, the fifth underflow slurry is used in a reslurry process to adjust the concentration of the crude potassium ore with moisture content less than or equal to 10%; and recovering the third filtrate to a pulp re-washing slurry concentration process for concentration.

According to the invention, the first overflow liquid, the third overflow liquid, the fifth overflow liquid and the first filtrate are respectively collected and recycled to the system, potassium chloride is recovered in the system, and the addition of foreign materials is replaced, so that the yield of potassium chloride is increased, and the cost is saved. In the invention, a plurality of devices such as the raw ore thickener 12, the flotation machine 32, the low-sodium thickener 41 and the like are connected in parallel, and the pulp mixing tank 22 adopts uniform pulp mixing, dispersing distribution and other modes, so that the treatment concentration of materials is uniform, and meanwhile, the parallel devices mutually form a standby relation, and even if a certain device fails or needs to be overhauled, the operation of the whole process is not influenced.

Drawings

FIG. 1 is a schematic diagram of a system for producing potassium chloride that can recycle byproducts;

FIG. 2 is a schematic diagram of an overflow and filtrate treatment system;

FIG. 3 is another schematic view of the first processing system;

FIG. 4 is a schematic diagram of a raw ore processing system;

FIG. 5 is a schematic view of a size mixing system;

FIG. 6 is a schematic diagram of a flotation system;

FIG. 7 is a schematic of a low sodium concentration and dehalogenation system;

FIG. 8 is a schematic diagram of a cold crystallization and crude potassium sieving system;

FIG. 9 is a schematic diagram of a crude potassium concentration and dehalogenation system;

FIG. 10 is a schematic of a fine potassium scrubbing and dehalogenation system; and

FIG. 11 is a schematic illustration of the steps of a process for producing potassium chloride with recycle of by-products.

Detailed Description

In the following detailed description of the preferred embodiments of the invention, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, specific features of the invention, such that the advantages and features of the invention may be more readily understood and appreciated. The following description is an embodiment of the claimed invention, and other embodiments related to the claims not specifically described also fall within the scope of the claims.

FIG. 1 shows a schematic of a system for producing potassium chloride that can recycle the byproducts.

As shown in fig. 1, a system for producing potassium chloride capable of recycling byproducts includes a raw ore processing system 1, a size mixing system 2, a flotation system 3, a low sodium concentration and dehalogenation system 4, a cold crystallization and crude potassium screening system 5, a crude potassium concentration and dehalogenation system 6, a fine potassium washing and dehalogenation system 7, and an overflow liquor and filtrate processing system 8, wherein the raw ore processing system 1 is used for screening and concentrating carnallite pulp to obtain a first underflow pulp and a first overflow liquor; the size mixing system 2 is connected with the raw ore processing system 1 and is used for mixing a flotation reagent with the first underflow slurry to obtain size mixing slurry; the flotation system 3 is used for carrying out flotation operation on the size mixing slurry to obtain tail salt and low-sodium carnallite slurry; the low-sodium concentration and dehalogenation system 4 is connected with the flotation system 3 and is used for concentrating the low-sodium carnallite slurry and removing brine to obtain a second overflow liquid, a first filtrate and low-sodium carnallite ore with the moisture content of less than or equal to 10%; the cold crystallization and crude potassium screening system 5 is connected with the low-sodium concentration and dehalogenation system 4 and is used for decomposing and crystallizing low-sodium carnallite ore with the moisture content of less than or equal to 10% and screening to obtain a third overflow liquid, crude potassium oversize products and crude potassium undersize products; the crude potassium concentration and dehalogenation system 6 is connected with the cold crystallization and crude potassium screening system 5 and is used for concentrating and dehalogenating the undersize of the crude potassium to obtain a fourth overflow liquid, a second filtrate and crude potassium ore with the moisture content of less than or equal to 10%; the refined potassium washing and dehalogenation system 7 is connected with the crude potassium concentration and dehalogenation system 6 and is used for washing and dehalogenating the crude potassium ore with the moisture content of less than or equal to 10% to obtain a third filtrate and refined potassium ore; and the overflow liquid and filtrate treatment system 8 is used for recovering and treating the first overflow liquid, the third overflow liquid, the fifth overflow liquid and the first filtrate.

The method takes carnallite produced in a salt pan as a raw material to produce potassium chloride, the main components of the carnallite collected from the salt pan are potassium chloride, sodium chloride and magnesium chloride, and the concentration of carnallite pulp is adjusted to ensure that the solid mass content of the carnallite pulp is more than or equal to 25 percent. The carnallite pulp is screened out impurities, large-particle salt and the like by a carnallite screening machine 11, and undersize products are conveyed to a raw ore thickener 12 for concentration to obtain first underflow slurry and first overflow liquid. The solids mass content of the first underflow slurry is adjusted to be in the range of 30-45% by adjusting the parameters of the thickening apparatus.

The first overflow liquid enters the overflow liquid and filtrate treatment system 8 for treatment.

And the first underflow slurry enters a slurry mixing system 2, a flotation reagent is added according to the mass content of the solid in the slurry, and the first underflow slurry and the flotation reagent are uniformly mixed in a stirring mode and the like to obtain the slurry mixing slurry.

The first underflow slurry and the flotation reagent are fully and uniformly mixed, so that the sodium flotation reagent can be fully contacted with sodium chloride in the flotation process, and the flotation efficiency can be increased.

The invention adopts a reverse flotation cold crystallization process, a flotation reagent is a sodium chloride collecting agent, and the concentration of the size mixing slurry needs to be adjusted before the size mixing slurry enters flotation equipment, so that the solid mass content of the size mixing slurry is as follows: 20% -25%, and further controlling the flotation efficiency.

During the reverse flotation process, the sodium chloride solids combine with the flotation reagent to form a froth that is discharged from the flotation system 3 as a tail salt, and a low sodium carnallite slurry is also obtained. The low-sodium carnallite slurry mainly comprises potassium chloride, magnesium chloride and a small amount of sodium chloride.

The low sodium carnallite slurry is firstly concentrated in the low sodium concentration and dehalogenation system 4, so that the solid mass content of the low sodium carnallite slurry reaches: 40-45%, concentrating to obtain a second overflow liquid, wherein the second overflow liquid is mainly a solution containing magnesium chloride, and then performing centrifugal dehalogenation to finally obtain a first filtrate and low-sodium carnallite ore with the moisture content of less than or equal to 10%.

The second overflow liquid can be used for the flotation system 3 to adjust the concentration of the size mixing slurry, the first filtrate is recycled by adopting the overflow liquid and the filtrate treatment system 8, and the low-sodium carnallite ore with the moisture content of less than or equal to 10 percent enters the next working procedure.

The low-sodium carnallite ore with the humidity less than or equal to 10 percent is conveyed to a cold crystallization and coarse potassium screening system 5 to be crystallized after decomposition of a decomposed mother liquor, the supersaturation degree of potassium chloride in a solution is controlled, the number of potassium chloride crystals is reduced, the aim of growing the potassium chloride crystals at normal temperature is fulfilled, sodium chloride cannot be separated out when the sodium chloride is in an unsaturated state, and the quality and the granularity of a potassium chloride product are ensured. Then, the screening operation is carried out, the undecomposed coarse carnallite on the screen returns to the crystallizer 51 for secondary decomposition, and the coarse kalium undersize is beneficial to the next working procedure.

And a third overflow liquid and a third underflow pulp are generated in the decomposition and crystallization process, and the third overflow liquid is used for recycling the overflow liquid and filtrate treatment system 8 and is used for synthesizing the decomposition mother liquor. The third underflow slurry has a solids mass content of 17-27% and is primarily undecomposed coarse carnallite and fine potassium chloride. And screening the third underflow ore pulp to obtain coarse potassium oversize products and coarse potassium undersize products, returning the coarse potassium oversize products to the crystallizer 51 for secondary decomposition, and feeding the coarse potassium undersize products into the coarse potassium concentration and dehalogenation system 6.

The crude potassium concentration and dehalogenation system 6 is used for concentrating the crude potassium undersize to obtain fourth underflow ore pulp and fourth overflow liquid, the mass content of solids in the fourth underflow ore pulp is 40% -45%, then the fourth underflow ore pulp is dehalogenated to obtain second filtrate and crude potassium ore with the moisture content of less than or equal to 10%, the second filtrate is returned to the concentration process for recovery, the fourth overflow liquid is sent to a raw ore screening system for carrying out blending and recovering carnallite in a liquid phase, and the crude potassium ore with the moisture content of less than or equal to 10% enters the next process.

The refined potassium washing and dehalogenation system 7 is used for washing the crude potassium ore with the moisture content of less than or equal to 10%, further dissolving magnesium chloride and potassium chloride, adding fresh water according to the conductivity, adjusting the concentration of the slurry to 40% -45% of the solid mass content, concentrating the washed slurry to obtain a fifth overflow liquid and a fifth underflow slurry, wherein the fifth overflow liquid is used for blending and decomposing mother liquor by the overflow liquid and filtrate treatment system 8, part of the fifth underflow slurry returns to the washing process for adjusting the concentration of the washed slurry, most of the fifth underflow slurry enters the dehalogenation process, dehalogenation is carried out on the fifth underflow slurry to obtain refined potassium ore with the moisture content of less than or equal to 10%, a third filtrate is also obtained in the dehalogenation process, and the third filtrate is used for recycling in the concentration process in the refined potassium washing and dehalogenation system 7.

Figure 2 shows a schematic of an overflow and filtrate treatment system.

As shown in fig. 2, the overflow liquid and filtrate processing system 8 includes a first processing system 81, a second processing system 82, and a third processing system 83, wherein the first processing system 81 is connected to the raw ore processing system 1 and the flotation system 3, respectively, and is configured to receive a first overflow liquid from the raw ore processing system 1, receive flotation tailings from the flotation system 3, and discharge the first overflow liquid and the flotation tailings after size mixing; the second treatment system 82 is connected with the cold crystallization and crude potassium screening system 5 and the refined potassium washing and dehalogenation system 7 respectively, and is used for receiving a third overflow liquid from the cold crystallization and crude potassium screening system 5, receiving a fifth overflow liquid from the refined potassium washing and dehalogenation system 7, adjusting the fifth overflow liquid with fresh water, and conveying the fifth overflow liquid to the cold crystallization and crude potassium screening system 5 to be used as a decomposition mother liquid; the third treatment system 83 is connected to the low-sodium concentration and dehalogenation system 4, and is configured to receive the first filtrate, concentrate and filter the first filtrate, and recover carnallite;

the flotation tail salt is foam with sodium chloride solid, is not convenient to discharge, and the first overflow liquid is mixed with the foam, so that the first overflow liquid can be conveniently conveyed. In addition, the flotation tail salt contains a large amount of sodium chloride, and can be used as a raw material for recovering the sodium chloride after being dissolved by the first overflow liquid.

The decomposition mother liquor is used in the cold crystallization and crude potassium sieving system 5 for decomposing slurry in the crystallization process.

The first filtrate contains fine-particle carnallite, and the fine-particle carnallite is filtered and recovered by a horizontal belt machine after being concentrated.

The first treatment system 81 may include a tail salt clarifier, a tail salt tank, etc. for receiving tail salt and the first overflow liquid so that the tail salt can be smoothly transported. The residual first overflow liquid can be discharged to a tail salt clarification tank, and is discharged to a carnallite salt field for recycling after standing.

The second treatment system 82 may be a dissolving tank that receives the third overflow liquid and the fifth overflow liquid and adds fresh water to prepare a decomposition mother liquid.

The third treatment system 83 includes a thickener and a centrifuge or a belt filter.

According to one embodiment of the invention, the low-sodium concentration and dehalogenation system 4 is connected to the flotation system 3 for delivering the second overflow liquid to the flotation system 3 for adjusting the concentration of the slurried slurry.

The second overflow liquid is preferentially conveyed to the flotation system 3 to adjust the concentration of the size-mixing slurry, and the redundant second overflow liquid can be returned to the carnallite salt pan for recycling.

According to one embodiment of the invention, the coarse potassium concentration and dehalogenation system 6 is connected to the raw ore treatment system 1 for sending the fourth overflow to the raw ore treatment system 1 for conditioning the carnallite pulp.

Fig. 3 shows another schematic view of the first processing system.

As shown in fig. 3, the first treatment system (81) further comprises a primary scavenging tank 811, a secondary scavenging tank 812 and a storage tank 813, wherein the primary scavenging tank 811 is connected with the flotation system and is used for receiving flotation tail salt and performing primary scavenging to obtain primary scavenging foam and primary scavenging underflow; the secondary scavenging slot 812 is connected with the primary scavenging slot 811 and is used for receiving the primary scavenging underflow and performing secondary scavenging to obtain secondary scavenging foam and secondary scavenging underflow; the primary scavenging groove 811 is connected with the tail salt pond and is used for conveying the primary scavenging foam to the tail salt pond; the secondary scavenger sump 812 is connected to the storage tank 813 for transferring the secondary scavenger underflow to the storage tank 813; the secondary scavenger tank 812 is connected to the low sodium concentration and dehalogenation system for conveying the secondary scavenger underflow to the low sodium concentration and dehalogenation system.

The primary scavenging groove 811 carries out primary scavenging on the flotation tail salt foam to obtain primary scavenging foam and primary scavenging underflow. Most of the flotation agents in the primary scavenging foam are combined with sodium chloride and are difficult to recycle. Meanwhile, the content of potassium chloride in the primary scavenging foam is low, and the potassium chloride in the primary scavenging foam is difficult to recover in the system to generate economic benefit. The secondary scavenger sump 812 is also designed to be lower than the primary scavenger sump 811 so that the first underflow flows into the secondary scavenger sump 812 for secondary scavenging, resulting in a secondary scavenged froth and a secondary scavenged underflow. The secondary scavenging underflow can also be conveyed to a low sodium thickener as low sodium slurry for subsequent processing. The secondary scavenging foam contains a large amount of flotation agents which are not combined with sodium chloride and are combined with potassium chloride in the primary scavenging process, but the potassium chloride is released to enter the flotation agents of the foam in the secondary scavenging process, and the flotation agents are the parts needing recycling.

The secondary scavenging foam is collected in the storage tank 813, and is conveyed to the flotation distribution tank by the conveying pump, so that on one hand, the flotation reagent is recovered, and on the other hand, the potassium chloride content in the secondary scavenging foam is higher, so that the recovery value is also achieved, the flotation effect is greatly improved, the flotation reagent is saved, and the yield of potassium chloride is improved.

Figure 4 shows a schematic diagram of a raw ore processing system.

As shown in fig. 4, the raw ore processing system 1 includes a carnallite screening machine 11 and a raw ore thickener 12, wherein the carnallite screening machine 11 is used for screening impurities and large-particle salts in carnallite pulp to obtain undersize products; the raw ore thickener 12 is connected to the carnallite screening machine 11, and is configured to concentrate the undersize product to obtain a first overflow liquid and a first underflow ore pulp, so that the first underflow ore pulp has a solid mass content: 30-45%, and one or more raw ore thickeners 12.

The carnallite pulp passes through the carnallite screening machine 11 to screen out impurities, large-particle salt and the like, the undersize product enters a raw ore thickener 12 to be concentrated, the first underflow pulp (the solid mass content: 30-35%) is pumped to a pulp conditioning system 2 by an underflow pump, one part of the first overflow liquid is used for being mixed with tail salt and is discharged, and the other part of the first overflow liquid is discharged to a carnallite salt field to be recycled.

The raw ore thickeners 12 may be arranged in parallel, even if a certain thickener fails, the operation of the whole production line is not affected. Or a multi-purpose and standby mode is adopted to keep the processing capacity of the total raw ore thickener 12 stable.

Fig. 5 shows a schematic view of a conditioning system.

As shown in fig. 5, the slurry mixing system 2 comprises a slurry distribution tank 21 and a slurry mixing tank 22, wherein the slurry distribution tank 21 comprises a plurality of raw ore thickeners 12 interfaces for connecting with the plurality of raw ore thickeners 12, receiving the first underflow slurry, mixing the first underflow slurry with a flotation reagent, and distributing the first underflow slurry and the flotation reagent to the slurry mixing tank 22; the slurry mixing tank 22 is connected to the slurry distribution tank 21, and is configured to uniformly mix the first underflow slurry and the flotation reagent to obtain a slurry mixture.

The slurry distribution tank 21 receives the first underflow slurry from the raw ore thickener 12, a flotation reagent is added into the slurry distribution tank 21 according to the mass content of solids in the first underflow slurry, then the slurry enters the slurry mixing tank 22, meanwhile, 0.5-0.7 Mpa air is input by an air compressor and enters an annular pipeline at the bottom of the slurry mixing tank 22, a large amount of bubbles with proper size emerge from air holes uniformly distributed on the annular pipeline, mechanical stirring is carried out in the slurry mixing tank 22, sodium chloride is selectively attached to the bubbles, finally the slurry enters the flotation distribution tank 31, slurry mixing mother liquor is added to adjust the concentration (mass content of solids: 20-25%), and then the slurry enters the flotation system 3.

The slurry distribution tank 21 is connected with the raw ore thickeners 12, the underflow slurries of the thickeners are mixed together, and the flotation reagents are also mixed, so that the components of the size mixing slurry are consistent before the flotation process, the flotation reagents are uniformly distributed in the size mixing slurry, and the flotation efficiency is improved.

Figure 6 shows a schematic of a flotation system.

As shown in fig. 6, the flotation system 3 includes a flotation distribution tank 31 and a flotation machine 32, and the flotation distribution tank 31 is connected to the size mixing system 2 and is configured to receive the size mixed slurry and perform concentration adjustment on the size mixed slurry by adding an adjustment mother liquor to obtain an adjusted slurry; the solid mass content of the adjusting slurry is 20-25%; the adjusting mother liquor refers to a liquid phase with the same component as the slurry mother liquor; the flotation machine 32 is connected with the flotation distribution tank 31 and is used for performing rough concentration, fine concentration and scavenging on the adjusted slurry to obtain tail salt and low-sodium carnallite pulp; the flotation machine 32 is one or more.

The flotation distribution tank 31 receives the slurry, adjusts the concentration of the slurry by adjusting the mother liquor, and then conveys the adjusted slurry to the plurality of flotation machines 32, so that the consistency of the material components of the flotation machines 32 is ensured, and the working parameters of the flotation machines 32 are conveniently and uniformly controlled. The flotation comprises three steps of rough concentration, fine concentration and scavenging to obtain tail salt and low-sodium carnallite pulp.

Similar to the raw ore thickener 12, there may be one or more flotation machines 32, and when there are multiple flotation machines 32, the flotation machines 32 are arranged side by side. The processing power of the present invention is increased.

The flotation distribution tank 31 keeps various properties of materials in each flotation machine 32 consistent, and flotation conditions are conveniently and uniformly set.

Figure 7 shows a schematic of a low sodium concentration and dehalogenation system.

As shown in fig. 7, the low-sodium concentration and dehalogenation system 4 comprises a low-sodium thickener 41, a low-sodium centrifuge distribution tank 42 and a low-sodium centrifuge 43, wherein the low-sodium thickener 41 is used for receiving low-sodium carnallite pulp and concentrating the low-sodium carnallite pulp to obtain a second underflow pulp and a second overflow liquid; the mass content of the second underflow ore pulp solid is 40-45%; one or more low-sodium thickeners 41; the low sodium centrifuge distribution tank 42 is connected to the low sodium thickener 41 for receiving the second underflow slurry and distributing the second underflow slurry to a low sodium centrifuge 43; the low-sodium centrifuges 43 are connected to the distribution tank 42 of the low-sodium centrifuges, and are used for dehalogenating the second underflow slurry to obtain a first filtrate and low-sodium carnallite ore with moisture content less than or equal to 10%.

The low-sodium thickener 41 receives the low-sodium carnallite ore and concentrates the low-sodium carnallite ore to obtain second underflow ore pulp and second overflow liquid, and the low-sodium thickener 41 is connected with the flotation distribution tank 31 and is used for conveying the second overflow liquid to the flotation distribution tank 31 to serve as adjusting mother liquid. The low-sodium thickener 41 controls the underflow flow and concentration to make the second underflow slurry have the following solid mass content: 40 to 45 percent to improve the yield of centrifugal dehalogenation. Meanwhile, the low-sodium thickener 41 may be a plurality of thickeners connected in parallel to the flotation machine 32, and the processing capacity of the low-sodium thickener 41 may be increased.

The low sodium centrifuge distribution tank 42 is connected to the low sodium thickener 41, and when the system includes a plurality of low sodium thickeners 41 connected in parallel, the second underflow slurry discharged from each low sodium thickener 41 can be uniformly mixed in the low sodium centrifuge distribution tank 42 and then distributed to the low sodium centrifuge 43 for dehalogenation.

The number of the low-sodium centrifuges 43 may be one or more, and when there are a plurality of the low-sodium centrifuges 43, the overall processing capacity may be increased, and when a certain low-sodium centrifuge 43 fails, the entire production line may be left unaffected.

Figure 8 shows a schematic of a cold crystallization and coarse potassium sieving system.

As shown in fig. 8, the cold crystallization and crude potassium sieving system 5 includes one or more crystallizers 51 and a crude potassium sieving machine 52, wherein the crystallizers 51 are used for receiving the low-sodium carnallite ore with moisture content less than or equal to 10% and decomposing and crystallizing to obtain a third underflow slurry and a third overflow liquid; the third underflow slurry solid mass content is 15-30%; the coarse potassium screening machine 52 is connected to the crystallizer 51, and is configured to screen the third underflow slurry to obtain coarse potassium oversize products and coarse potassium undersize products.

The crystallizer 51 is connected with the low-sodium centrifuge 43, the centrifuged low-sodium carnallite ore with the moisture content less than or equal to 10 percent enters the crystallizer 51, meanwhile, decomposition mother liquor is added, the low-sodium carnallite ore is decomposed and crystallized at a controlled speed, the supersaturation degree of potassium chloride in the solution is controlled by controlling the decomposition conditions of the low-sodium carnallite ore, the number of potassium chloride crystals is reduced, the purpose of growing the potassium chloride crystals at normal temperature is achieved, the sodium chloride is in an unsaturated state and cannot be separated out, and the quality and the granularity of the potassium chloride product are ensured. And obtaining a third underflow ore pulp and a third overflow liquid. The solid mass content of the third underflow slurry is 17-27%, the third underflow slurry is sent to a coarse potassium separator for screening, coarse carnallite which is not decomposed and is oversize is returned to the crystallizer 51 for secondary decomposition, and coarse potassium undersize enters a coarse potassium thickener 61. The third overflow liquid is processed by the overflow liquid and filtrate processing system 8 and is used for preparing decomposition mother liquid.

Figure 9 shows a schematic of a crude potassium concentration and dehalogenation system.

As shown in fig. 9, the crude potassium concentrating and dehalogenating system 6 comprises a crude potassium thickener 61, a crude potassium centrifuge distribution tank 62 and a crude potassium centrifuge 63, wherein the crude potassium thickener 61 is one or more than one for receiving and concentrating the crude potassium undersize to obtain a fourth overflow liquid and a fourth underflow pulp; the solid mass content of the fourth underflow slurry is 40-45%; the crude potassium centrifuge distribution tank 62 is connected to the crude potassium thickener 61, and is configured to receive the fourth underflow slurry and distribute the fourth underflow slurry to each crude potassium centrifuge 63; and one or more crude potassium centrifuges 63 are connected with the crude potassium centrifuge distribution tank 62 and used for dehalogenating the fourth underflow slurry to obtain a second filtrate and crude potassium ore with the moisture content of less than or equal to 10%.

The coarse potassium thickener 61 receives the coarse potassium undersize, and concentrates the coarse potassium undersize to obtain a fourth underflow ore pulp and a fourth overflow liquid. The fourth underflow slurry has a solid mass content of 40-45%, and is conveyed to a coarse potassium centrifuge distribution tank 62 to be uniformly distributed to a coarse potassium centrifuge 63 for dehalogenation, so as to obtain a second filtrate.

Wherein, the crude potassium thickener 61 is connected with the crude ore thickener 12 of the crude ore processing system 1, and is used for conveying the fourth overflow liquid to the crude ore thickener 12 to recover carnallite therein.

The crude potassium centrifuge 63 is connected with the crude potassium thickener 61, and the second filtrate is conveyed from the crude potassium centrifuge 63 to the crude potassium thickener 61 for recycling.

According to one embodiment of the invention, the coarse potassium centrifuge 63 is connected to the coarse potassium thickener 61 for transporting the second filtrate to the coarse potassium thickener 61 for recycling.

Figure 10 shows a schematic of a fine potassium wash and dehalogenation system.

As shown in fig. 10, the fine potassium washing and dehalogenation system 7 includes one or more repulping washing tanks 71, a fine potassium thickener 72 and a fine potassium centrifuge 73, and the repulping washing tanks 71 are used for receiving and washing the crude potassium ore with moisture content less than or equal to 10% to obtain repulping washing slurry; one or more fine potassium thickeners 72 are matched with the repulping and washing tank and used for concentrating the repulping and washing slurry to obtain fifth underflow slurry; one or more fine potassium centrifuges 73 are matched with the fine potassium thickener 72 and used for dehalogenating the fifth underflow slurry to obtain fine potassium ore and third filtrate; the moisture content of the refined potassium ore is less than or equal to 10 percent.

According to one embodiment of the invention, the fine potassium thickener 72 is connected to the reslurry wash tank for adjusting the concentration of the crude potassium ore with a moisture content of 10% or less using the fifth underflow slurry. The fine potassium thickener 72 is connected to the fine potassium centrifuge 73, and is configured to recycle the third filtrate to the fine potassium thickener 72 for concentration.

The coarse potassium ore with the moisture content less than or equal to 10% is obtained after the centrifugation of the coarse potassium centrifuge 63, the coarse potassium ore enters the repulping washing tank 71, fresh water is added according to the conductivity, and the slurry concentration in the repulping washing tank 71 is adjusted to achieve the solid mass content by utilizing the fifth underflow pulp of the fine potassium thickener 72: 40% -45%, and feeding the washed slurry into a refined potassium thickener 72 for concentration to obtain a fifth overflow liquid and a fifth underflow slurry. Most of the fifth underflow slurry enters the fine potassium centrifuge 73 for dehalogenation to obtain wet potassium chloride (fine potassium ore, moisture content less than or equal to 10%), and part of the wet potassium chloride is used for adjusting the slurry concentration in the repulping washing tank 71.

The third filtrate returns to a refined potassium thickener 72 for recycling.

The fifth overflow liquid is recovered by the overflow liquid and filtrate treatment system 8 for use in configuring the decomposition mother liquor for the crystallizer 51.

FIG. 11 shows a schematic of the steps of a process for producing potassium chloride with recycle of by-products.

As shown in fig. 11, a method for producing potassium chloride capable of recycling byproducts includes a first step S1 of screening and concentrating carnallite pulp to obtain a first underflow pulp and a first overflow liquid; a second step S2 of mixing a flotation reagent with the first underflow slurry to obtain a size mixing slurry; step S3, carrying out flotation operation on the size mixing slurry to obtain tail salt and low-sodium carnallite slurry; a fourth step S4, concentrating the low-sodium carnallite slurry and removing brine to obtain a second overflow liquid, a first filtrate and low-sodium carnallite ore with the moisture content less than or equal to 10%; a fifth step S5, decomposing and crystallizing the low-sodium carnallite ore with the moisture content less than or equal to 10%, and sieving to obtain a third overflow liquid, a coarse potassium oversize product and a coarse potassium undersize product; a sixth step S6, concentrating and dehalogenating the coarse potassium undersize to obtain a fourth overflow liquid, a second filtrate and coarse potassium ore with the moisture content less than or equal to 10%; a seventh step S7, washing and dehalogenating the crude potassium ore with the moisture content less than or equal to 10% to obtain a third filtrate and refined potassium ore; an eighth step S8 of recovering and processing the first overflow liquid, the third overflow liquid, the fifth overflow liquid, and the first filtrate.

According to an embodiment of the present invention, the eighth step S8 includes discharging the first overflow liquid after being size-mixed with the flotation tail salt; receiving the third overflow liquid and the fifth overflow liquid, and using the third overflow liquid and the fifth overflow liquid as decomposition mother liquid of a crystallization process after fresh water regulation; and receiving the first filtrate, concentrating and filtering the first filtrate, and recovering the carnallite.

According to one embodiment of the invention, the method further comprises the steps of subjecting the flotation tail salt to primary scavenging to obtain primary scavenging foam and primary scavenging underflow; performing secondary scavenging on the primary scavenging underflow to obtain secondary scavenging foam and secondary scavenging underflow; mixing the primary scavenging foam and the first overflow liquid, and conveying the mixture to a tail salt pond; the secondary scavenger bottom stream is conveyed to the low sodium concentration and dehalogenation system.

According to one embodiment of the invention, the second overflow liquid is used for adjusting the concentration of the size-mixed slurry.

According to one embodiment of the invention, the fourth overflow is used for conditioning a carnallite slurry.

According to one embodiment of the present invention, the first step S1 includes screening out impurities and large particle salts in the carnallite slurry to obtain undersize product; concentrating the undersize product to obtain a first overflow liquid and a first underflow pulp, and ensuring the solid mass content of the first underflow pulp to be: 30% -45%; the solid mass content of the carnallite pulp is more than or equal to 25 percent.

According to one embodiment of the invention, the second step S2 includes mixing the first underflow slurry with a flotation reagent and distributing the first underflow slurry and the flotation reagent; and uniformly mixing the first underflow slurry and the flotation reagent to obtain size mixing slurry.

According to an embodiment of the present invention, the third step S3 includes adjusting the concentration of the conditioned slurry by adding an adjusting mother liquor to obtain an adjusted slurry; the solid mass content of the adjusting slurry is 20-25%; the adjusting mother liquor refers to a liquid phase with the same component as the slurry mother liquor; and carrying out rough concentration, fine concentration and scavenging on the adjusted slurry to obtain tail salt and low-sodium carnallite pulp.

According to an embodiment of the present invention, the fourth step S4 includes concentrating the low sodium carnallite pulp to obtain a second underflow pulp and a second overflow liquid; the mass content of the second underflow ore pulp solid is 40-45%; distributing the second underflow slurry; and dehalogenating the second underflow ore pulp to obtain a first filtrate and low-sodium carnallite ore with the moisture content of less than or equal to 10%.

According to an embodiment of the present invention, the fifth step S5 includes mixing the low-sodiumniosulgite ore with moisture content less than or equal to 10% with decomposition mother liquor, performing controlled-speed decomposition crystallization to obtain a third underflow slurry and a third overflow solution; the third underflow slurry solid mass content is 15-30%; and screening the third underflow slurry to obtain coarse potassium oversize products and coarse potassium undersize products.

According to one embodiment of the invention, the sixth step S6 includes concentrating the potassium rejects to obtain a fourth overflow and a fourth underflow slurry; the solid mass content of the fourth underflow slurry is 40-45%; distributing the fourth underflow slurry; and dehalogenating the fourth underflow slurry to obtain a second filtrate and crude potassium ore with the moisture content of less than or equal to 10%.

According to one embodiment of the invention, the second filtrate is sent to a process for concentrating the undersize of crude potassium for recycling.

According to an embodiment of the invention, the seventh step S7 includes washing the crude potassium ore with moisture content less than or equal to 10% to obtain reslurry washing slurry; concentrating the repulped and washed slurry to obtain fifth underflow slurry; dehalogenating the fifth underflow slurry to obtain fine potassium ore and third filtrate; the moisture content of the refined potassium ore is less than or equal to 10 percent.

According to one embodiment of the invention, the concentration of the crude potassium ore having a moisture content of 10% or less is adjusted in the reslurry process using the fifth underflow slurry. And recovering the third filtrate to a pulp re-washing slurry concentration process for concentration.

According to the invention, the first overflow liquid, the third overflow liquid, the fifth overflow liquid and the first filtrate are respectively collected and recycled to the system, potassium chloride is recovered in the system, and the addition of foreign materials is replaced, so that the yield of potassium chloride is increased, and the cost is saved. In the invention, a plurality of devices such as the raw ore thickener 12, the flotation machine 32, the low-sodium thickener 41 and the like are connected in parallel, and the pulp mixing tank 22 adopts uniform pulp mixing, dispersing distribution and other modes, so that the treatment concentration of materials is uniform, and meanwhile, the parallel devices mutually form a standby relation, and even if a certain device fails or needs to be overhauled, the operation of the whole process is not influenced.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.