阅读说明：本技术 基于除尘灰的冷压球生产工艺 (Cold-pressed ball production process based on fly ash ) 是由 严礼祥 严升 于 2021-10-27 设计创作，主要内容包括：本发明涉及金属冶炼技术领域,具体而言,为一种基于除尘灰的冷压球生产工艺。步骤如下：S1原料配比：所述原料包括除尘灰和氧化铁皮,将所述原料按一定的质量比进行配比,得到物料A；S2混料：将所述物料A进行初步搅拌后,再将其送入混料机中并加入粘接剂和水再次进行搅拌混匀,得到物料B；S3预压成型：将所述物料B送入预压压球机中进行初步塑形和固定,得到物料C；S4压球成型：将所述物料C送入成品压球机进行压球成型,得到含有湿粉和成型冷压球的物料D,并将湿粉筛出重新进行步骤S3预压成型；S5成品除水：将成型冷压球进行除水处理。能够解决除尘灰综合回收利用难的问题,使除尘灰和氧化铁皮等废弃物能够进行有效循环利用。(The invention relates to the technical field of metal smelting, in particular to a production process of a cold-pressed ball based on fly ash. The method comprises the following steps: s1 raw material ratio: the raw materials comprise dedusting ash and iron scale, and are proportioned according to a certain mass ratio to obtain a material A; s2 mixing: primarily stirring the material A, then feeding the material A into a mixer, adding an adhesive and water, and stirring and uniformly mixing again to obtain a material B; s3 pre-pressing forming: sending the material B into a pre-pressing ball press machine for preliminary shaping and fixing to obtain a material C; s4 ball pressing and forming: feeding the material C into a finished product ball press machine for ball pressing and forming to obtain a material D containing wet powder and formed cold-pressed balls, screening out the wet powder, and performing step S3 pre-pressing and forming again; s5 dewatering of the finished product: and (5) carrying out water removal treatment on the molded cold-pressed ball. The problem that the comprehensive recycling of the dedusting ash is difficult can be solved, and the dedusting ash, iron scale and other wastes can be effectively recycled.)

1. A cold-pressed ball production process based on fly ash is characterized by comprising the following steps:

s1 raw material ratio: the raw materials comprise dedusting ash and iron scale, and are proportioned according to a certain mass ratio to obtain a material A;

s2 mixing: feeding the material A into a mixer (1), adding an adhesive and water, and uniformly stirring to obtain a material B;

s3 pre-pressing forming: sending the material B into a pre-pressing ball press machine (2) for preliminary shaping and fixing to obtain a material C;

s4 ball pressing and forming: feeding the material C into a finished product ball press machine (3) for ball pressing and forming to obtain a material D containing wet powder and formed cold-pressed balls;

s5 dewatering of the finished product: and (5) carrying out water removal treatment on the molded cold-pressed ball.

2. The cold-pressed pellet production process based on fly ash according to claim 1, wherein: in S2, the material A is primarily stirred and uniformly mixed before being fed into the mixer (1).

3. The cold-pressed pellet production process based on fly ash according to claim 1, wherein: and S4, screening out the wet powder, and performing prepressing molding again in the step S3.

4. The cold-pressed pellet production process based on fly ash according to claim 1, wherein: and S5, drying the formed cold-pressed balls in air or in a drying mode to remove water.

5. The cold-pressed pellet production process based on fly ash of claim 4, wherein: the airing time is 36-48 hours.

6. The cold-pressed pellet production process based on fly ash according to claim 1, wherein: in S2, the mixing time is 15 minutes.

7. The cold-pressed pellet production process based on fly ash according to claim 1, wherein: the content of the dedusting ash is 70% -100%.

8. The cold-pressed pellet production process based on fly ash according to claim 1, wherein: the content of the adhesive is 3% -6%.

9. The cold-pressed pellet production process based on fly ash according to claim 1, wherein: the content of the iron scale is 30%.

10. The cold-pressed pellet production process based on fly ash of claim 3, wherein: and S4, screening the wet powder by using a vibrating screen.

Technical Field

The invention relates to the technical field of metal smelting, in particular to a production process of a cold-pressed ball based on fly ash.

Background

In the production process of a steel mill, a large amount of dust is generated, the dust and iron scale generated in the steel mill at present are basically transferred to a sintering ingredient, and pig iron or waste steel needs to be purchased from a cold material for steelmaking. The fly ash and the iron scale directly enter the sintering ingredients to influence the water-carbon ratio of the ingredients and the stability of alkalinity, and particularly harmful elements such as alkali metal and the like in the sintering ingredients have influence on the furnace condition after entering the blast furnace and are not beneficial to the smooth operation of the blast furnace. Meanwhile, the dust and the iron scale are sintered, ironmade and steelmaking, so that the fuel consumption and the load of a dust removal system are increased, and the energy consumption is increased.

The domestic steelmaking fly ash basically realizes closed cycle in a factory, the prior basic method is used for sintering production, but the fly ash is clinker, the hydrophilicity is poor, the sintering material granulation effect is poor, the sintering yield and the sintering quality are greatly influenced by using excessive fly ash, but the fly ash can only be used for sintering without a better method. In China, colleges and iron and steel enterprises have carried out a lot of tests, and the dedusting ash is treated by cold-pressed pellets, but the cold-pressed pellets prepared by the traditional process have low strength and cannot meet the requirements of iron making and steel making.

The recycling degree of difficulty of steel mill dust is great, and it is great to sintering deposit quality influence after using to sinter, in order to solve the difficult problem of dust removal comprehensive recycling, makes wastes such as dust removal ash and iron scale can carry out effective cyclic utilization, and the waste material becomes the steel to realize the virtuous circle of steelmaking process. Meanwhile, the environmental pollution is reduced and the energy consumption is saved.

(1) Necessity of project construction

Firstly, about 40% of iron is contained in the steelmaking fly ash, and along with the rising of the processing price of metallurgical raw materials such as mineral powder and waste materials, people also pay attention to the fact that the steelmaking fly ash contains a large amount of valuable metal elements, so that the resources are reasonably utilized, the purchasing cost of iron and steel enterprises can be reduced, a resource circulating chain can be formed inside the enterprises, considerable economic benefits are brought to the enterprises, and the environmental protection pressure of steel plants is greatly reduced.

Secondly, the steel industry not only consumes a large amount of resources and energy, but also discharges a large amount of waste, and along with the enhancement of environmental awareness of people, the cyclic recycling of the fly ash has very important environmental protection and social significance, and the resources are reasonably utilized, so that the enterprise environment can be improved, and the social responsibility of enterprises is reflected.

(2) Feasibility of project construction

The disposal of the dust removal ash has been going through takeaway, sintering batching and ball pressing so far, wherein the takeaway has been forbidden, the entering sintering batching influences the stability of alkalinity due to the influence on the water-carbon ratio of the batching, especially after harmful elements such as alkali metal enter the blast furnace, the influence on the furnace condition is generated, which is not beneficial to the smooth operation of the blast furnace, meanwhile, the dust removal ash and iron scale are sintered, ironmaking and steelmaking, the fuel consumption and the load of a dust removal system are increased, and the energy consumption is increased, therefore, most steel mills seek other treatment modes, and the ball pressing emphasizes on the recovery of valuable metal elements in the dust removal ash, so that the value available for the dust removal ash is realized to the maximum extent, and the ball pressing is also the main attack direction in the field of dust removal ash disposal in recent years. However, the cold-pressed pellets prepared by the traditional process have low strength and cannot meet the requirements of iron making and steel making.

In conclusion, the process method for effectively treating the fly ash can completely and effectively treat the harm caused by the fly ash and obtain good economic benefit.

Therefore, there is a need for a cold-pressed pellet production process based on fly ash that can solve the above problems.

Disclosure of Invention

In view of the above, the invention aims to provide a production process of cold-pressed balls based on fly ash, which enables waste materials such as fly ash and iron scale to be effectively recycled, and enables waste materials to be changed into steel, thereby realizing virtuous cycle of a steel-making process. Meanwhile, the environmental pollution is reduced and the energy consumption is saved.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention provides a production process of cold-pressed balls based on fly ash, which comprises the following steps:

s1 raw material ratio: the raw materials comprise dedusting ash and iron scale, and are proportioned according to a certain mass ratio to obtain a material A;

s2 mixing: primarily stirring the material A, then feeding the material A into a mixer, adding an adhesive and water, and stirring and uniformly mixing again to obtain a material B;

s3 pre-pressing forming: sending the material B into a pre-pressing ball press machine for preliminary shaping and fixing to obtain a material C;

s4 ball pressing and forming: feeding the material C into a finished product ball press machine for ball pressing and forming to obtain a material D containing wet powder and formed cold-pressed balls;

s5 dewatering of the finished product: and (5) carrying out water removal treatment on the molded cold-pressed ball.

Further, in S2, the material a is primarily mixed and stirred before being fed into the mixer.

Further, in S4, the wet powder is sieved out and the pre-pressing forming in step S3 is carried out again

Further, in S5, the molded cold-pressed balls are dehydrated by airing or drying.

Furthermore, the airing time is 36-48 hours.

Further, in S2, the mixing time was 15 minutes.

Further, the content of the dedusting ash is 70% -100%.

Further, the content of the adhesive is 3% -6%.

Further, the content of the iron scale is 30%.

Further, in S4, the wet powder is sieved with a vibrating sieve.

The invention has the beneficial effects that:

the production process of the cold-pressed ball based on the fly ash can solve the problem that the fly ash is difficult to comprehensively recycle, so that the fly ash, iron scale and other wastes can be effectively recycled, and the wastes are changed into steel, thereby realizing virtuous cycle of the steelmaking process, simultaneously reducing environmental pollution and saving energy consumption.

Drawings

In order to make the object, technical scheme and beneficial effect of the invention more clear, the invention provides the following drawings for explanation:

FIG. 1 is a process flow diagram of the production process of cold-pressed balls based on fly ash according to the present invention;

figure 2 is a plan view of a production line for cold-pressed ball production.

Description of reference numerals:

1-a mixer; 2-prepressing a ball press; 3-a finished ball press; 4-dust removal ash tank; 5-an iron scale bin; 6-a buffer bin; 7-iron oxide skin tank.

Detailed Description

The present invention is further described with reference to the following drawings and specific examples so that those skilled in the art can better understand the present invention and can practice the present invention, but the examples are not intended to limit the present invention.

As shown in fig. 1, which is a process flow diagram of an embodiment of a process for producing cold-pressed balls based on fly ash according to the present invention, the process equipment mainly used in this embodiment is shown in the following table:

TABLE 1 Process units

The production process of the cold-pressed ball based on the fly ash comprises the following steps:

s1 raw material ratio: the raw materials in the embodiment comprise dedusting ash and iron scale, as shown in fig. 2, the two raw materials are respectively stored in a dedusting ash tank 4 and an iron scale bin 5, and the raw materials are proportioned according to a certain mass ratio to obtain a material A; specifically, the raw material ratio is as follows:

the content of reference dust is 70%, the content of iron scale is 30% and the content of adhesive is 3% -6%. The proportion of the ingredients is a recommended proportion, and the final proportion can be adjusted according to the requirements of owners. In special cases, the fly ash can be adjusted to 100% (but this will affect the balling effect and increase the cost).

S2 mixing: and (3) sending the material A into a double-shaft stirrer for preliminary stirring, then sending the material A into a mixer 1, adding the adhesive and water, stirring again for 15 minutes, and uniformly mixing to obtain a material B. Specifically, a buffer bin 6 is arranged between the dedusting ash tank 4, the iron scale bin 5 and the mixer 1, the buffer bin 6 can provide a storage space for temporary storage and buffering of materials before mixing, an iron scale tank 7 is further arranged between the iron scale bin 5 and the buffer bin 6, the iron scale bin 5 and the iron scale tank 7 are connected through a belt conveyor, the discharge end of the belt conveyor is arranged at the top of the iron scale tank 7, a vibrating screen for screening iron scales is arranged at the top of the iron scale tank 7, the vibrating screen can screen large iron scales and then fall to the ground through a falling pipeline, and small-sized powdery iron scales enter the iron scale tank 7; the spiral ash conveying machine for conveying ash in a spiral metering proportion is connected to the ash removing tank 4, a double-shaft mixer for primarily mixing the dust removing ash and the iron oxide scales is connected to the discharge end of the spiral ash conveying machine, the double-shaft mixer is connected with the mixer 1 through a belt conveyor, the iron oxide scales with small sizes are weighed through the weighing belt conveyor and then are conveyed into the spiral ash conveying machine in proportion, the mixed materials are conveyed into the double-shaft mixer through the belt conveyor to be primarily mixed, the primarily mixed materials are conveyed into the buffer bin 6 through the belt conveyor for standby, and the materials in the buffer bin 6 are conveyed into the mixer 1 through the weighing belt conveyor and then are added with the adhesive and water to be uniformly mixed;

s3 pre-pressing forming: sending the material B into a pre-pressing ball press machine 2 for preliminary shaping and fixing to obtain a material C; and carrying out a pre-pressing process on the material B to form a material C with a certain shape and structure, so as to be beneficial to carrying out ball pressing and forming on the material C subsequently. Specifically, the mixer 1 and the pre-pressing ball press 2 of the embodiment are connected by a belt conveyor;

s4 ball pressing and forming: the pre-pressing ball press machine 2 is connected with the finished product ball press machine 3 through a belt conveyor, the material C is sent into the finished product ball press machine 3 to be pressed and molded to obtain a material D containing wet powder and molded cold-pressed balls, the wet powder is screened out and is pre-pressed and molded again in the step S3, the material D obtained after the material C is pressed and molded to obtain the material D containing the wet powder which is not molded and contains certain moisture, the wet powder is screened onto a material returning belt conveyor through a vibrating screen and is conveyed into the pre-pressing ball press machine 2 again to be pre-pressed, the large circulation of ore returning can be effectively avoided, and the wet powder is processed in the middle link;

s5 dewatering of the finished product: and (5) carrying out water removal treatment on the molded cold-pressed ball. Specifically, in this embodiment, the water removal treatment is performed by using a natural stacking and air drying manner for the balls, and since the adhesive can perform self-heating, the balls can be naturally stacked for 36-48 hours (which varies according to the time in summer and winter), so that the moisture content of the balls is less than or equal to 5.0%, and the use requirements are met. Of course, the drying method can also be used to remove water from the balls.

In summary, the production process of the cold-pressed ball based on the fly ash in the embodiment is as follows:

dedusting ash and iron scale, batching, mixing, ball pressing (prepressing), ball pressing, airing and finished product

Conveying the fly ash to a production line by using a closed tank car, and conveying the fly ash into a fly ash tank by using compressed air (nitrogen) (wherein part of steel plants can also use a dump truck to convey the wet fly ash to the production line);

and after primary stirring, adding a binder and water into the fly ash and the iron scale by using a mixer, stirring again, sending the fly ash into a ball press machine after stirring to preliminarily pre-press and press balls, and sending the fly ash into the ball press machine through a conveying system after pre-pressing to press the balls again. Conveying the pelletized product to a screening position through a conveying system for screening, returning returned materials at the bottom of a screen after screening to a pre-pressing ball press machine for re-pressing the pellets, and feeding oversize materials (and finished products) into a finished product stock yard for stockpiling. And (4) after the finished product is aired, the water content is not more than 5.0%, and the finished product is sent to a steel converter for use.

The quality parameters of the cold-pressed balls subjected to pre-pressing forming and airing are as follows:

TABLE 2 product quality parameters

Serial number	Parameters of finished product	Requirements for the finished product
			1	Maximum dimension of outer shape	30～50mm
2	Strength of	1500N/ball +/-500N/ball
			3	Water content	Not more than 5.0 percent

The technical indexes of the cold-pressed balls after prepressing forming and airing are as follows:

cold strength (compressive strength)

The concept is as follows: the compressive strength (crushing strength of pellets) refers to the maximum crushing load of the pressed pellet and is an index for representing the mechanical strength of the pellet. Iron ore pellets undergo numerous handling, transfer, stacking and movement before and after entering a blast furnace or direct reduction furnace, and are subjected to various severe mechanical actions such as collision, impact, extrusion and friction. Under the action of the mechanical action, a part of pellet ore is crushed to generate small blocks and powder, thereby influencing the furnace condition and the production index.

Influence: the compressive strength of the pellets directly affects the amount of fines and powder in the kiln. The compression strength of the pellet ore is high, the powder in the kiln is less, the material layer has good air permeability, the smooth operation of the kiln protection is facilitated, the yield of the kiln can be improved, the industrial dust can be reduced, and the environment can be improved. 1000m³The compression strength of the oxidized and roasted pellets used in the large blast furnace is more than or equal to 2000N/pellet, and the compression strength required by the pellets used in the medium and small blast furnaces can be properly relaxed.

Thermal behavior (Low temperature reduction degradation index, thermal decrepitation index)

The iron ore (sintered ore and pellet) is cracked and pulverized in the low-temperature reduction process. In the blast furnace ironmaking process, after iron ore enters a blast furnace, furnace burden is lowered to a temperature of 400-600 ℃, and the furnace burden is subjected to the reduction action of coal gas from the lower part of the blast furnace and is cracked and pulverized to different degrees. In severe cases, the permeability of the upper material column of the blast furnace is affected, and the smooth operation of the furnace is damaged. Most factories stipulate that the RDI +3.15 of sinter is more than or equal to 65 percent.

Thermal decrepitation is an important metallurgical property of iron ore. Mainly in natural iron ores. Therefore, the method for testing the thermal decrepitation of iron ore has not been formally standardized. Some germany plants have adopted a certain test method and do not use it as a measure of clinker. Most plants specify sinter DI-3.15< 10%.

The cold-pressed balls of the sample (No. 1) according to the table 3 and the table 5 have the bursting temperature of more than 500 ℃, the bursting index of 2.24 percent and far less than 10 percent, the average compressive strength of 2688.64N, high compressive strength and almost no bursting. The pulverization rate is low.

The cold-pressed balls of the sample (No. 2) have the bursting temperature of more than 500 ℃, the bursting index of 3.20 percent and far less than 10 percent according to the table 4 and the table 6, the average compressive strength of 4314.24N, higher compressive strength and low pulverization rate.

The metallurgical performance of the cold-pressed ball in the experiment basically meets the standard requirement, and the blast furnace can be properly added for smelting.

TABLE 3 compressive Strength of Cold pressed balls (N)

Sample (number 1)	1	2	3	4	5	Mean value of
							Compressive Strength (N)	2192.0	2413.9	3262.9	2213.3	3361.1	2688.64

TABLE 4 compressive Strength of Cold pressed balls (N)

Sample (number 2)	1	2	3	4	5	Mean value of
							Compressive Strength (N)	4811.7	3745.1	5426.1	4884.3	2704.0	4314.24

TABLE 5 Cold pressed pellet burst temperature and burst index (No. 1 briquetting)

TABLE 6 Cold pressing pellet burst temperature and burst index (No. 2 briquetting)

Dust:

the dust generated in the project is mainly as follows: the dust that each transfer station of conveying system transportation produced, the produced dust of stoving product, this dust pelletizing system of pressing the ball line divide into two parts: the production system removes dust and the drying system removes dust.

Dedusting of feeding system

The dedusting ash and the iron scale are respectively loaded into a bin by a loader after being delivered to a production workshop by a covered dump truck, the loading materials are delivered to a double-shaft mixer by a conveying system, the materials are mixed and then enter a buffer bin, a powerful mixer and a vertical shaft planetary mixer are carried out after being measured by a belt scale, meanwhile, a special adhesive is added, the materials are uniformly mixed and then delivered to a ball press for prepressing, the materials are delivered to the ball press by the conveying system for balling again after the prepressing is finished, and finally, the materials are aired to remove water or delivered to a dryer for drying and removing water after the balling is finished. The dust removal of production system dust removal point includes: the dust removal of each blanking point of a storage bin, a stirrer, a ball press, a conveying system and the like is realized, a bag-type dust remover is adopted as a dust remover, the emission concentration of the treated dust is less than or equal to 10mg/Nm³。

The dust removal system adopts PLC full-automatic control, and the switch board, the PLC system and the monitoring system are placed in an electric room.

Dust removal of drying system (if adopting drying and dewatering)

The finished balls after cold press molding are conveyed to a dryer through a belt conveyor, a drying system comprises a burner, a dryer main body, an air supply fan, a moisture extraction fan and the like, and after the finished balls are dried, the moisture content of the finished balls reaches within 5 percent, and the finished balls can be transported to a finished product area to be stored or conveyed to an iron-making blast furnace for use.

The dust emission concentration of the dust after the dust removal treatment of the drying system is less than or equal to 10mg/Nm³。

The present embodiment also includes a production system for dedusting a production site for removing various dusts generated from the production line.

In conclusion, the production process of the cold-pressed ball based on the dedusting ash can solve the problem that the dedusting ash is difficult to comprehensively recycle, so that the dedusting ash, iron scales and other wastes can be effectively recycled, and the wastes are changed into steel, thereby realizing virtuous cycle of a steelmaking process, reducing environmental pollution and saving energy consumption.

The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.