阅读说明：本技术 一种基于锂聚合物的元明粉制备方法 (Preparation method of anhydrous sodium sulphate based on lithium polymer ) 是由 何开茂 何东利 伍震洲 汪梨超 代道和 杨贤丽 江莹 谭培渊 黄剑新 于 2020-12-30 设计创作，主要内容包括：本发明公开了一种基于锂聚合物的元明粉制备方法,属于元明粉制备技术领域,包括以下步骤：将锂聚合物依次经过煅烧、冷却、细磨、加酸反应、冷却,调浆,浸出压榨分离,分离出来的清液进入冷冻系统预冷后泵入结晶器结晶析出硫酸钠,分离出的十水硫酸钠进入融晶罐溶解后进行蒸发浓缩,后通过离心分离和烘干得到元明粉成品。本制备方法能生产出高质量的元明粉,运用了连续冷冻结晶技术分离出硫酸钠,保证晶核稳定成长以及生产的连续性,能生产出高品质的产品,同时缩短了生产周期,节约了成本。(The invention discloses a preparation method of anhydrous sodium sulphate based on a lithium polymer, belonging to the technical field of anhydrous sodium sulphate preparation, and comprising the following steps: the lithium polymer is sequentially subjected to calcining, cooling, fine grinding, acid reaction, cooling, size mixing, leaching, squeezing and separation, the separated clear liquid enters a freezing system for precooling, then is pumped into a crystallizer for crystallization to separate out sodium sulfate, the separated sodium sulfate decahydrate enters a crystal melting tank for dissolving, then is subjected to evaporation and concentration, and finally is subjected to centrifugal separation and drying to obtain a finished product of anhydrous sodium sulfate. The preparation method can produce high-quality anhydrous sodium sulphate, uses the continuous freezing and crystallizing technology to separate the sodium sulphate, ensures the stable growth of crystal nucleus and the continuity of production, can produce high-quality products, shortens the production period and saves the cost.)

1. A preparation method of anhydrous sodium sulphate based on lithium polymer is characterized by comprising the following steps:

s1, calcining, cooling, finely grinding, adding acid for reaction and cooling a lithium polymer in sequence, cooling a product of the acid addition reaction to be less than or equal to 90 ℃, and then adding water to prepare slurry, wherein the solid content of the slurry is 10-70%; the granularity of fine grinding is required to be 200 meshes, and the calcining temperature is 950-1200 ℃; and (3) adding acid for reaction, adding sulfuric acid with the concentration of 98%, wherein the acid-material ratio is 2-5: 1;

s2, adding calcium carbonate slurry into the slurry obtained in the step S1, stirring and leaching, adjusting the pH value to 5.5-6, adding calcium oxide after leaching for 20 minutes to adjust the pH value to 8-9, then filtering by using a filter press, rinsing the filter cake by using tap water or process water, purging the filter cake by using compressed air to ensure that the water content of the filter cake is less than or equal to 20%, returning the obtained rinsing water to the step S1 for slurry mixing, purifying the filtered clear liquid by using an alkaline solution, adjusting the pH value to 9-12, and removing impurities of iron, manganese, aluminum and calcium in the filtered clear liquid;

s3, filtering the clear filtrate obtained in the step S2 again to obtain purified liquid and purified filter residues, adding water into the purified filter residues to prepare slurry with the solid content of 10% -70%, returning to the step S1, and causticizing the purified liquid by using an alkaline solution with the concentration of 10% -50%;

s4, filtering the solution causticized in the step S3 to obtain a causticized liquid and causticized filter residues, adding water into the causticized filter residues to prepare slurry with the solid content of 10-70%, returning to the step S2 for purification, and filtering the causticized liquid through a precision filter to remove part of calcium ions;

s5, pumping the causticized liquid which is filtered by the precision filter and part of calcium ions are removed in the step S4 into a freezing system, and cooling the causticized liquid by using the forced freezing action of an ice machine, wherein the freezing temperature is-5 to-20 ℃; crystallizing and separating out sodium sulfate in the form of sodium sulfate decahydrate at low temperature, and dissolving the sodium sulfate decahydrate separated from the solution in a mirabilite melting tank under the centrifugal separation effect;

s6, evaporating, concentrating and purifying sodium sulfate decahydrate, heating, taking out crystal water to obtain anhydrous sodium sulfate, heating at the temperature of 200-800 ℃, centrifugally separating the concentrated anhydrous sodium sulfate slurry, drying an anhydrous sodium sulfate wet product by a flash evaporation dryer to obtain anhydrous sodium sulfate, drying at the temperature of 50-150 ℃, and returning the centrifuged mother liquor to a mirabilite melting tank or a purification tank;

and S7, carrying out gas-solid separation on anhydrous sodium sulphate obtained after drying by the flash evaporation dryer in the step S6 through a two-stage cyclone separator, and packaging the solid anhydrous sodium sulphate by an automatic packaging machine and then warehousing.

2. The method of claim 1, wherein the reaction is performed by adding acid in step S1, and then cooling the reaction product to a temperature below 60 ℃.

3. The method of claim 1, wherein in step S2, the calcium carbonate slurry is prepared from calcium carbonate and water, the slurry has a solid content of 10-55%, and the temperature in the leaching tank is 60 ℃ or lower.

4. The method of claim 1, wherein the alkaline solution is calcium oxide or lithium hydroxide solution, and the concentration of the lithium hydroxide solution is 10-50% if lithium hydroxide solution is added, or the calcium oxide is powder with a mass fraction of more than 75% or calcium oxide slurry with a solid content of 10-55% if calcium oxide is added in step S2.

5. The method for preparing anhydrous sodium sulfate based on lithium polymer according to claim 1, wherein in step S3, the alkaline solution is sodium hydroxide solution, lithium hydroxide solution or a mixture solution of the two; the pH value of the causticized solution is 11-14, and the temperature is normal temperature.

6. The method for preparing anhydrous sodium sulphate based on lithium polymer according to claim 1, wherein the clear frozen solution separated from the solution during centrifugation in step S5 is transferred to a buffer tank for the frozen solution, filtered by a ultrafilter, and then transferred to a crude product feeding buffer tank.

7. The method of claim 1, wherein the hot air required by the flash dryer is provided by a hot air furnace in step S6, and the fuel of the hot air furnace is natural gas and is used in an amount of 600m³/h。

8. The method of claim 1, wherein the water content of the solid anhydrous sodium sulfate obtained by gas-solid separation in step S7 is 5%.

Technical Field

The invention belongs to the technical field of anhydrous sodium sulphate preparation, and particularly relates to a preparation method of anhydrous sodium sulphate based on a lithium polymer.

Background

Glauber salt refers to sodium sulfate, also called mirabilite. Sodium sulfate, an inorganic compound, sodium sulfate decahydrate, also known as mirabilite, and a high-purity, finely-grained anhydrate called glauber salt. The anhydrous sodium sulphate is mainly used for manufacturing water glass, porcelain glaze, paper pulp, refrigerating mixing agent, detergent, drying agent, dye diluent, analytical chemical reagent, medicinal products, feed and the like. The main methods for producing anhydrous sodium sulphate at present are a beach field method, a mechanical freezing method, a salt lake comprehensive utilization method and the like.

The beach field method is to evaporate water from the material liquid by means of the temperature change in different seasons to crystallize out coarse mirabilite. In summer, the salt water containing sodium chloride, sodium sulfate, magnesium chloride, etc. is poured into beach field, and after sun-drying and evaporation, crude mirabilite is separated out in winter. The method is a main method for extracting mirabilite from natural resources, and has the advantages of simple process, low energy consumption, poor operation conditions and easy mixing of impurities such as sand and the like in the product.

The mechanical freezing method is to utilize mechanical equipment to heat and evaporate the raw material liquid and then freeze the raw material liquid to-5 to-10 ℃ to separate out mirabilite. Compared with the beach field method, the method is not affected by seasons and natural conditions. The product quality is good, but the energy consumption is high.

The comprehensive utilization method of the salt lake is mainly used for sulfate-carbonate type salt water containing various components. The crude mirabilite is separated while extracting various useful components. For example, salt lake water containing sodium carbonate, sodium sulfate, sodium chloride, boride, potassium, bromine and lithium can be processed by firstly carbonizing salt lake brine to convert sodium carbonate into sodium bicarbonate to be crystallized; cooling the mother liquor to 5-15 ℃ to crystallize borax; and (4) freezing the secondary mother liquor after borax separation to 0-5 ℃, and separating out mirabilite.

Therefore, how to prepare anhydrous sodium sulphate with high quality and low cost is a problem to be solved in the field.

Disclosure of Invention

The invention aims to provide a preparation method of anhydrous sodium sulphate based on a lithium polymer, which aims to solve the problem that the existing preparation method is difficult to produce the anhydrous sodium sulphate with high quality and low cost.

In order to realize the purpose of the invention, the technical scheme is as follows: a preparation method of anhydrous sodium sulphate based on lithium polymer comprises the following steps:

s1, calcining, cooling, finely grinding, adding acid for reaction and cooling a lithium polymer in sequence, cooling a product of the acid addition reaction to be less than or equal to 90 ℃, and then adding water to prepare slurry, wherein the solid content of the slurry is 10-70%; the granularity of fine grinding is required to be 200 meshes, and the calcining temperature is 950-1200 ℃; and (3) adding acid for reaction, adding sulfuric acid with the concentration of 98%, wherein the acid-material ratio is 2-5: 1;

s2, adding calcium carbonate slurry into the slurry obtained in the step S1, stirring and leaching, adjusting the pH value to 5.5-6, adding calcium oxide after leaching for 20 minutes to adjust the pH value to 8-9, then filtering by using a filter press, rinsing the filter cake by using tap water or process water, purging the filter cake by using compressed air to ensure that the water content of the filter cake is less than or equal to 20%, returning the obtained rinsing water to the step S1 for slurry mixing, purifying the filtered clear liquid by using an alkaline solution, adjusting the pH value to 9-12, and removing impurities of iron, manganese, aluminum and calcium in the filtered clear liquid;

s3, filtering the clear filtrate obtained in the step S2 again to obtain purified liquid and purified filter residues, adding water into the purified filter residues to prepare slurry with the solid content of 10% -70%, returning to the step S1, and causticizing the purified liquid by using an alkaline solution with the concentration of 10% -50%;

s4, filtering the solution causticized in the step S3 to obtain a causticized liquid and causticized filter residues, adding water into the causticized filter residues to prepare slurry with the solid content of 10-70%, returning to the step S2 for purification, and filtering the causticized liquid through a precision filter to remove part of calcium ions;

s5, pumping the causticized liquid which is filtered by the precision filter and part of calcium ions are removed in the step S4 into a freezing system, and cooling the causticized liquid by using the forced freezing action of an ice machine, wherein the freezing temperature is-5 to-20 ℃; crystallizing and separating out sodium sulfate in the form of sodium sulfate decahydrate at low temperature, and dissolving the sodium sulfate decahydrate separated from the solution in a mirabilite melting tank under the centrifugal separation effect;

s6, evaporating, concentrating and purifying sodium sulfate decahydrate, heating, taking out crystal water to obtain anhydrous sodium sulfate, heating at the temperature of 200-800 ℃, centrifugally separating the concentrated anhydrous sodium sulfate slurry, drying an anhydrous sodium sulfate wet product by a flash evaporation dryer to obtain anhydrous sodium sulfate, drying at the temperature of 50-150 ℃, and returning the centrifuged mother liquor to a mirabilite melting tank or a purification tank;

and S7, carrying out gas-solid separation on anhydrous sodium sulphate obtained after drying by the flash evaporation dryer in the step S6 through a two-stage cyclone separator, and packaging the solid anhydrous sodium sulphate by an automatic packaging machine and then warehousing.

As a further alternative, the acid is added in step S1 for reaction and then cooled to below 60 ℃.

As a further alternative, in step S2, the calcium carbonate slurry is prepared by calcium carbonate and water, the solid content of the slurry is 10-55%, and the temperature in the leaching tank is less than or equal to 60 ℃.

As a further alternative, in step S2, the alkaline solution is calcium oxide or lithium hydroxide solution, and if lithium hydroxide solution is added, the concentration of the lithium hydroxide solution is 10% to 50%, and if calcium oxide is added, the calcium oxide is powder with a mass fraction of more than 75% or calcium oxide slurry with a solid content of 10% to 55%.

As a further alternative, in step S3, the alkaline solution is a sodium hydroxide solution, a lithium hydroxide solution, or a mixed solution of the two, the pH of the causticized solution is 11-14, and the temperature is normal temperature.

As a further alternative, the frozen clear solution separated from the solution during the centrifugal separation in the step S5 is transferred to a frozen post-liquid buffer tank, filtered by a precision filter, and then enters a crude product feeding buffer tank.

As a further alternative, it is possible to,in step S6, hot air required by the flash evaporation dryer is provided by a matched hot blast stove, the fuel of the hot blast stove is natural gas, and the usage amount is 600m³/h。

Alternatively, in step S7, the water content of the solid anhydrous sodium sulfate obtained by gas-solid separation is 5%.

The invention has the beneficial effects that: the preparation method takes lithium polymer as raw material, and the grade of the lithium polymer reaches 8.5-12 percent (Li)₂O), Al content 25.05%, Mg content 1.23%, Si content 0.84%, Mn content 0.69%, impurity content is few, it is a new mineral source, can produce high-quality anhydrous sodium sulphate, this preparation method has used the continuous freezing crystallization technology to separate out sodium sulphate, guarantee the stable growth of crystal nucleus and continuity of production, can produce the high-quality product, have shortened the production cycle at the same time, has saved the cost.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, it should be understood that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a process flow diagram of a method for preparing anhydrous sodium sulfate based on lithium polymer according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention. It is to be understood that the drawings are provided solely for the purposes of reference and illustration and are not intended as a definition of the limits of the invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

The invention is further described with reference to the following figures and specific embodiments.

Fig. 1 shows a preparation method of anhydrous sodium sulphate based on lithium polymer, which comprises the following steps:

s1, calcining, cooling, finely grinding, adding acid for reaction and cooling a lithium polymer in sequence, cooling a product of the acid addition reaction to be less than or equal to 90 ℃, and then adding water to prepare slurry, wherein the solid content of the slurry is 10-70%; the granularity of fine grinding is required to be 200 meshes, and the calcining temperature is 950-1200 ℃; and (3) adding acid for reaction, adding sulfuric acid with the concentration of 98%, wherein the acid-material ratio is 2-5: 1;

s2, adding calcium carbonate slurry into the slurry obtained in the step S1, stirring and leaching, adjusting the pH value to 5.5-6, adding calcium oxide after leaching for 20 minutes to adjust the pH value to 8-9, then filtering by using a filter press, rinsing the filter cake by using tap water or process water, purging the filter cake by using compressed air to ensure that the water content of the filter cake is less than or equal to 20%, returning the obtained rinsing water to the step S1 for slurry mixing, purifying the filtered clear liquid by using an alkaline solution, adjusting the pH value to 9-12, and removing impurities of iron, manganese, aluminum and calcium in the filtered clear liquid;

s3, filtering the clear filtrate obtained in the step S2 again to obtain purified liquid and purified filter residues, adding water into the purified filter residues to prepare slurry with the solid content of 10% -70%, returning to the step S1, and causticizing the purified liquid by using an alkaline solution with the concentration of 10% -50%;

s4, filtering the solution causticized in the step S3 to obtain a causticized liquid and causticized filter residues, adding water into the causticized filter residues to prepare slurry with the solid content of 10-70%, returning to the step S2 for purification, and filtering the causticized liquid through a precision filter to remove part of calcium ions;

s5, pumping the causticized liquid which is filtered by the precision filter and part of calcium ions are removed in the step S4 into a freezing system, and cooling the causticized liquid by using the forced freezing action of an ice machine, wherein the freezing temperature is-5 to-20 ℃; crystallizing and separating out sodium sulfate in the form of sodium sulfate decahydrate at low temperature, and dissolving the sodium sulfate decahydrate separated from the solution in a mirabilite melting tank under the centrifugal separation effect;

s6, evaporating, concentrating and purifying the sodium sulfate decahydrate obtained in the step S5, heating to take out crystal water to obtain anhydrous sodium sulfate, heating to 200-800 ℃, centrifugally separating the concentrated anhydrous sodium sulfate slurry, drying an anhydrous sodium sulfate wet product by a flash evaporation dryer to obtain anhydrous sodium sulfate, drying to 50-150 ℃, and returning the centrifuged mother liquor to a mirabilite crystal melting tank or a purification tank;

s7, carrying out gas-solid separation on anhydrous sodium sulfate obtained after drying by the flash evaporation dryer in the step S6 through a two-stage cyclone separator, and packaging the solid anhydrous sodium sulfate by an automatic packaging machine and then warehousing.

Most of the impurities iron, manganese, aluminium and calcium may be precipitated out in the leaching stage and filtered off through the leached filter residue as a filter cake.

In step S1, the reaction mixture is cooled to below 60 ℃ after acid addition reaction.

In step S2, the calcium carbonate slurry is prepared by calcium carbonate and water, the solid content of the slurry is 10-55%, and the temperature in the leaching tank is less than or equal to 60 ℃.

In step S2, the alkaline solution is calcium oxide or lithium hydroxide solution, if lithium hydroxide solution is added, the concentration of the lithium hydroxide solution is 10% to 50%, and if calcium oxide is added, the calcium oxide is powder with a mass fraction of more than 75% or calcium oxide slurry with a solid content of 10% to 55%.

In step S3, the alkaline solution is a sodium hydroxide solution, a lithium hydroxide solution or a mixed solution of the sodium hydroxide solution and the lithium hydroxide solution, the pH of the causticized solution is 11-14, and the temperature is normal temperature.

And S5, transferring the frozen clear liquid separated from the solution during centrifugal separation into a frozen liquid buffer barrel, filtering the frozen clear liquid by a precision filter, and feeding the filtered clear liquid into a crude product feeding buffer barrel.

In step S6, hot air required by the flash evaporation dryer is provided by a matched hot blast stove, the fuel of the hot blast stove is natural gas, and the usage amount is 600m³/h。

In step S7, the water content of the solid anhydrous sodium sulfate obtained by gas-solid separation is 5%.

The method comprises the steps of carrying out high-temperature calcination transformation, cooling, ball milling, acidification roasting, cooling, slurry mixing, leaching, squeezing and separation on lithium polymer, enabling separated clear liquid to enter a freezing system, precooling the clear liquid by a three-stage precooler, pumping the clear liquid into a crystallizer, separating out sodium sulfate by two-stage continuous freezing crystallization, enabling sodium sulfate decahydrate separated from the solution to enter a crystal melting tank through the separation action of a horizontal sedimentation centrifuge and a two-stage pusher centrifuge, transferring the separated frozen clear liquid into a frozen liquid buffer tank, filtering the frozen clear liquid by a precision filter, enabling the frozen clear liquid to enter a crude product feeding buffer tank, dissolving the sodium sulfate decahydrate in the crystal melting tank, removing the dissolved sodium sulfate decahydrate in an MVR evaporation system for evaporation and concentration, carrying out centrifugal separation on concentrated anhydrous sodium sulfate crystal slurry, drying an anhydrous sodium sulfate wet product by a flash evaporation dryer to obtain a gla.

The preparation method uses the lithium polymer as a raw material to produce the anhydrous sodium sulphate, the lithium polymer has high grade and low impurity content, is a novel mineral source and can produce high-quality lithium hydroxide monohydrate.

The invention is not limited to the above alternative embodiments, and any other various forms of products can be obtained by anyone in the light of the present invention, but any changes in shape or structure thereof, which fall within the scope of the present invention as defined in the claims, fall within the scope of the present invention.