阅读说明：本技术 一种降低转炉钢渣中磷含量的方法 (Method for reducing phosphorus content in converter steel slag ) 是由 钱强 范泽宇 张入元 宋文德 于 2020-11-20 设计创作，主要内容包括：本发明公开了一种降低转炉钢渣中磷含量的方法,包括以下步骤：将转炉钢渣破碎、筛分、磁选后获得渣料；向获得渣料交替喷洒水和有机酸溶液,当渣料底部出现流淌液停止喷洒,每喷洒一种液体后静置2-5天再喷洒另一种液体；重复上述喷洒操作5-10次,然后将最终的渣料晾干即可。该方法可有效解决现有的方法存在的磷脱方法不适合于大规模的工业生产的问题。(The invention discloses a method for reducing the phosphorus content in converter steel slag, which comprises the following steps: crushing, screening and magnetically separating the converter steel slag to obtain slag charge; alternately spraying water and an organic acid solution on the obtained slag, stopping spraying when a flowing liquid appears at the bottom of the slag, and spraying another liquid after standing for 2-5 days after spraying one liquid; and repeating the spraying operation for 5-10 times, and then airing the final slag material. The method can effectively solve the problem that the existing phosphorus removal method is not suitable for large-scale industrial production.)

1. A method for reducing the phosphorus content in converter steel slag is characterized by comprising the following steps:

(1) crushing, screening and magnetically separating the converter steel slag to obtain slag charge;

(2) alternately spraying water and an organic acid solution on the slag charge in the step (1), stopping spraying when a flowing liquid appears at the bottom of the slag charge, and spraying another liquid after standing for 2-5 days after each liquid is sprayed;

(3) and (3) repeating the operation in the step (2) for 5-10 times, and then airing the final slag.

2. The method for reducing the phosphorus content in the converter steel slag according to claim 1, wherein the particle size of the slag in the step (1) is 0.5 to 1.5 cm.

3. The method for reducing the phosphorus content in the converter steel slag according to claim 2, wherein the particle size of the slag in the step (1) is 0.8 cm.

4. The method for reducing the phosphorus content in the steel slag of the converter as claimed in claim 1, wherein the magnetic separation strength in the step (1) is 4000-.

5. The method for reducing the phosphorus content in the converter steel slag according to claim 4, wherein the magnetic separation intensity in the step (1) is 4500 Gs.

6. The method for reducing the phosphorus content in the steel slag of the converter according to claim 1, wherein the organic acid solution in the step (2) is citric acid solution, and the pH value of the organic acid solution is 2-5.

7. The method for reducing the phosphorus content in the converter steel slag according to claim 1, wherein the spraying of one liquid in the step (2) is continued after standing for 4 days.

8. The method for reducing the phosphorus content in the converter steel slag according to claim 1, wherein the slag is dried after repeating the operation in the step (2) for 8 times.

Technical Field

The invention relates to the technical field of smelting, in particular to a method for reducing the phosphorus content in converter steel slag.

Background

The steel slag is a large solid waste with the lowest comprehensive utilization rate in the steel industry in China, the comprehensive utilization of the steel slag is one of the important signs of the technical progress of the modern steel industry, and the steel slag is also the inevitable requirement for the development of the green recyclable ecological steel industry. According to the calculation of 120kg of steel slag generated by smelting 1t of steel, the steel industry in China generates approximately 1 million tons of steel slag every year. The developed industrial countries pay attention to the comprehensive utilization technology of the steel slag, and the utilization rate of the steel slag in the countries of America, Germany, Japan and the like is more than 90 percent. At present, the comprehensive utilization rate of steel slag in China is only 25% -30%, the comprehensive utilization rate is obviously different from that of developed countries, a large amount of steel slag is piled up and treated due to the fact that the steel slag cannot be effectively utilized every year in China, a large amount of land is occupied, the ecological environment is damaged, and meanwhile, resource waste is caused.

With the continuous return of the converter steel slag to the sintering system, phosphorus elements can be continuously and circularly recycled, and if the phosphorus content in the steel-climbing converter slag is enriched to more than 0.6% at present from 0.2% at the beginning of 2000 years and is increased at a speed doubled every five years, the phosphorus content brings higher dephosphorization pressure to the steelmaking process, and the converter slag is not beneficial to being converted into blast furnace slag with higher utilization rate. The proportion of the converter slag in the sintering process is lower than 1.5 percent and far lower than the original 4 percent. Therefore, the low-phosphorus converter slag powder is used for realizing the continuous utilization. It would be desirable to provide a method for achieving a reduction in elemental phosphorus to facilitate flux usage in a ferrous metallurgical sintering system.

At present, the dephosphorization research of steel slag mainly comprises the following steps: (1) a flotation method: the phosphorus in the steel slag is removed by utilizing the floating phenomenon of the phosphorus-containing silicate, but the problems of incomplete solid-liquid phase separation, low phosphorus removal rate and the like exist; (2) magnetic separation method: the method comprises the steps of firstly utilizing the converter steel slag modification or other methods to promote the enrichment rate of phosphorus in a non-magnetic phase such as silicate, and then realizing the separation from a magnetic phase such as iron oxide by a magnetic separation mode, but the strong magnetic (Mg, Mn) O & Fe₂O₃Is easy to be mixed with 2CaO SiO₂The embedded cloth is formed, magnetic separation is disturbed, and complete removal of phosphorus is difficult to realize; (3) reduction method: namely, under high temperature, the phosphorus in the steel slag is gasified and removed or reduced into molten iron by reducing agents such as carbon, silicon and the like, but a better dephosphorization effect can be achieved only under the condition of higher temperature; (4) leaching with strong acid or strong base: namely, the steel slag is treated by strong acid or strong base, but the iron loss and the post-treatment problem of the strong acid and the strong base are caused. Moreover, many of the existing methods are in the test stage and cannot be applied to large-scale production.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a method for reducing the phosphorus content in converter steel slag, which can effectively solve the problem that the phosphorus removal method in the prior art is not suitable for large-scale industrial production.

In order to achieve the purpose, the technical scheme adopted by the invention for solving the technical problems is as follows:

a method for reducing the phosphorus content in converter steel slag comprises the following steps:

(1) crushing, screening and magnetically separating the converter steel slag to obtain slag charge;

(2) alternately spraying water and an organic acid solution on the slag charge in the step (1), stopping spraying when a flowing liquid appears at the bottom of the slag charge, and spraying another liquid after standing for 2-5 days after each liquid is sprayed;

(3) and (3) repeating the operation in the step (2) for 5-10 times, and then airing the final slag.

In the scheme, the converter steel slag is crushed, screened and magnetically separated to obtain the steel slag with higher phosphorus content and smaller volume, then water and organic acid are sprayed on the steel slag, and the water and the organic acid are utilized to react with phosphorus in the steel slag to dissolve out the phosphorus, so that the leaching rate of the phosphorus in the steel slag can be improved.

When water is sprayed, part of calcium phosphate in the steel slag is gradually dissolved in the water to leach out phosphorus, when the acid solution is continuously sprayed on the steel slag, the phosphorus dissolved out by the organic acid solution is washed out of the surface of the steel slag, and meanwhile, the organic acid solution can also continuously react with the phosphorus in the steel slag to leach out the phosphorus, so that the organic acid is weaker in corrosivity and more convenient for subsequent collection treatment; when the two liquids are alternately sprayed on the surface of the steel slag, the phosphorus element in the steel slag is gradually dissolved from the surface to the inside and then separated from the steel slag, so that the in-out efficiency of the phosphorus element is improved.

Further, the grain diameter of the slag in the step (1) is 0.5-1.5 cm.

Further, the grain size of the slag in the step (1) is 0.8 cm.

In the scheme, the obtained slag charge has the particle size limited to 0.5-1.5cm, the particle size of the slag charge is moderate, phosphorus in the slag charge can be fully leached after multiple pressurizing and infiltrating reactions, the particle size of the slag charge is 0.5-1.5cm, no large dust is generated in the production process, and the environmental protection and convenience of the method are further improved.

Further, the magnetic separation intensity in the step (1) is 4000-.

Further, the magnetic separation intensity in the step (1) is 4500 Gs.

In the scheme, the slag blocks with high metal content in the steel slag can be fully separated and enriched through the magnetic separation strength of 4000-5000Gs, so that the subsequent leaching treatment is convenient.

Further, the acid solution in the step (2) is citric acid solution, and the pH value is 2-5.

In the scheme, citric acid can react with calcium phosphate in the steel slag to replace phosphorus, and when the pH value of the citric acid is 2-5, the reaction effect is best, the leaching rate of phosphoric acid is highest, the pH value is too large, the cost is increased, and the leaching rate is slow due to too small pH value.

Further, after spraying one liquid in the step (2), standing for 4 days, and continuously spraying the other liquid.

In the scheme, different liquids are alternately sprayed, phosphorus in the steel slag is leached layer by layer through different reactions, the reaction time is properly increased, the use amount of the reaction leaching liquid is reduced, the practical practicability of the method is improved, and the method is suitable for large-scale industrial production.

And (3) further, repeating the operation in the step (2) for 8 times, and then airing the slag.

In the scheme, after the operation is repeated for 8 times, the phosphorus element in the steel slag is basically leached out, so that the steel slag can be reused after being dried in the air.

The beneficial effects produced by the invention are as follows:

in the invention, the steel slag is infiltrated by using two liquids of water and acid solution alternately, so that the two liquids react with calcium phosphate in the steel slag respectively to leach out phosphorus elements, thereby realizing the aim of dephosphorizing the steel slag. The raw materials of water and acid solution are easy to obtain, the cost is low, the using amount in the invention is less, and the production cost can be greatly reduced; the operation method is simple, convenient to operate, small in structure and simple in structure of used equipment, and is suitable for large-scale industrial production.

Detailed Description

Example 1

A method for reducing the phosphorus content in converter steel slag comprises the following steps:

(1) crushing, screening and magnetically separating the converter steel slag to obtain a slag charge, wherein the particle size of the slag charge obtained by the magnetic separation strength of 4000Gs is 0.5 cm;

(2) alternately spraying water and citric acid solution with the pH value of 3 on the slag charge in the step (1), stopping spraying when flowing liquid appears at the bottom of the slag charge, and spraying another liquid after standing for 2 days after spraying one liquid each time;

(3) and (3) repeating the operation in the step (2) for 5 times, and then airing the final slag material.

Example 2

A method for reducing the phosphorus content in converter steel slag comprises the following steps:

(1) crushing, screening and magnetically separating the converter steel slag to obtain slag, wherein the particle size of the slag obtained with the magnetic separation strength of 5000Gs is 1.5 cm;

(2) alternately spraying water and citric acid solution with the pH value of 5 on the slag charge in the step (1), stopping spraying when flowing liquid appears at the bottom of the slag charge, and spraying another liquid after standing for 5 days after spraying one liquid each time;

(3) and (3) repeating the operation in the step (2) for 10 times, and then airing the final slag material.

Example 3

A method for reducing the phosphorus content in converter steel slag comprises the following steps:

(1) crushing, screening and magnetically separating the converter steel slag to obtain a slag charge, wherein the particle size of the slag charge is 0.8cm, and the magnetic separation strength is 4500 Gs;

(2) alternately spraying water and citric acid solution with the pH value of 4 on the slag charge in the step (1), stopping spraying when flowing liquid appears at the bottom of the slag charge, and spraying another liquid after standing for 3 days after spraying one liquid each time;

(3) and (3) repeating the operation in the step (2) for 8 times, and then airing the final slag material.

Example 4

A method for reducing the phosphorus content in converter steel slag comprises the following steps:

(1) crushing, screening and magnetically separating the converter steel slag to obtain slag, wherein the particle size of the slag obtained with the magnetic separation strength of 4200Gs is 1.2 cm;

(2) alternately spraying water and citric acid solution with the pH value of 5 on the slag charge in the step (1), stopping spraying when flowing liquid appears at the bottom of the slag charge, and spraying another liquid after standing for 4 days after spraying one liquid each time;

(3) and (3) repeating the operation in the step (2) for 6 times, and then airing the final slag material.

Comparative example 1

A method for reducing the phosphorus content in converter steel slag comprises the following steps:

(1) crushing, screening and magnetically separating the converter steel slag to obtain slag, wherein the particle size of the slag obtained with the magnetic separation strength of 3000Gs is 2 cm;

(2) alternately spraying water and citric acid solution with the pH value of 2 on the slag charge in the step (1), stopping spraying when flowing liquid appears at the bottom of the slag charge, and spraying another liquid after standing for 1 day after spraying one liquid;

(3) and (3) repeating the operation in the step (2) for 3 times, and then airing the final slag material.

Test examples

Taking converter steel slag of a certain steel mill, detecting the content of phosphorus element in the converter steel slag, dividing the steel slag into 5 parts, carrying out dephosphorization treatment on the 5 parts of the steel slag by adopting the methods in examples 1-4 and comparative example 1, and detecting the content of the phosphorus element in each part of the steel slag after treatment, wherein the specific results are shown in Table 1.

Table 1: phosphorus element content in converter steel slag before and after dephosphorization

	Phosphorus content (%)% of steel slag before dephosphorization	Phosphorus content (%) -in dephosphorized steel slag
			Example 1	0.68％	0.49％
Example 2	0.68％	0.46％
			Example 3	0.68％	0.37％
Example 4	0.68％	0.42％
			Comparative example 1	0.68％	0.61％

It can be seen from the data in the above table that, after the phosphorus removal is performed by the methods in examples 1 to 4, the decrease of the phosphorus content in the steel slag is large, especially, the decrease of the phosphorus in example 3 is the largest, and the decrease of the phosphorus in comparative example 1 is small, which proves that each process parameter in the treatment process has a certain influence on the phosphorus removal.