Phosphating residue chemical comprehensive utilization treatment method

Abstract

The application discloses a kind of phosphating slag chemical comprehensive utilization processing method, comprising the following steps: phosphating slag pretreatment;Phosphating slag is placed in sodium hydroxide solution, and filtrate and precipitate A are collected;Hydrochloric acid is added in filtrate, then urotropine, thiourea, ethanedioic acid tetraethylammonium, hydrogen peroxide acid are added, and filtrate and precipitate B are collected;Decolorization;Extraction;Precipitation;Precipitate A and precipitate B are ball milled after being added into hydrochloric acid aqueous solution, then polydodecyl acrylamide acrylic acid is added, to obtain filtrate;Phosphoric acid aqueous solution is further added in filtrate;Aluminum hydroxide or aluminum oxide and iron phosphate product are further added, stirred, filtered, dried, and ball milled.The phosphating slag solid waste generated in the process of steel metal product is used as raw material, iron phosphate is prepared through pretreatment, alkali leaching, acid treatment, decolorization, extraction and precipitation reaction, etc., to meet the standard requirements.The zinc-containing precipitate is further treated to prepare ternary phosphate anti-rust pigment.

Description

Technical Field

[0001] The invention relates to a comprehensive chemical utilization treatment method for phosphating slag, and belongs to the technical field of phosphating slag treatment. Background Art

[0002] During the production of steel and metal products, the phosphating treatment of steel surfaces produces solid waste phosphating slag. In addition to a certain amount of water, the main components of phosphating slag are iron phosphate and zinc phosphate. Analysis shows that the mass content of each component in phosphating slag is approximately: water accounts for 15-20%, TFe (Fe 3+ and Fe 2+ ) accounts for 15-25%, Zn 2+ 2-5%, PO4 3- In addition, phosphating slag also contains a small amount of Ca 2+ Mg 2+ 、Mn 2+ 、Ni 2+ 、Cu 2+ The total mass content of impurity elements such as phosphating slag is about 0.5-2.0%. Since phosphating slag solid waste has been included in the "National Hazardous Waste List", if it is discharged without treatment, it will cause environmental pollution and waste recyclable valuable chemical resources.

[0003] When phosphating slag is made into iron phosphate as the raw material of lithium iron phosphate, other elements such as zinc will be removed and wasted. How to design a chemical comprehensive utilization treatment method for phosphating slag to make better use of the elements in it has become a problem to be solved. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for chemical comprehensive utilization of phosphating slag, which can make better use of the elements in the phosphating slag.

[0005] In order to solve the above-mentioned technical problems, the purpose of the present invention is achieved as follows:

[0006] The present invention relates to a method for comprehensive chemical utilization of phosphating slag, comprising the following steps:

[0007] S1. Phosphating slag pretreatment: crush the phosphating slag into particles with a diameter of 100-500 microns, then place the particles in a phosphoric acid aqueous solution, heat in a water bath and stir; after precipitation, remove the upper foam, and pass the slag through a 250-mesh sieve in water, retain the sieve residue, filter it with suction, dry it and set aside;

[0008] S2. Alkaline leaching of phosphating slag: The phosphating slag after pretreatment is placed in a 30% by mass sodium hydroxide solution for a certain period of time, and then water is added to adjust the pH value to 10-11. The reaction is continued for a certain period of time, and the slag is passed through a 500 mesh sieve, and the filtrate and precipitate A are collected;

[0009] S3, acid treatment: hydrochloric acid is added to the filtrate obtained in the previous step to adjust the pH value to 6-6.5, and then a solution consisting of hexamethylenetetramine, thiourea, tetraethylammonium oxalate, and hydrogen peroxide is added and stirred for a certain period of time, filtered, and the filtrate and precipitate B are collected;

[0010] S4. Decolorization: Add activated carbon to the filtrate obtained in the previous step, stir for adsorption, filter, and collect the filtrate.

[0011] S5, extraction: adding an extractant and an organic solution to the liquid prepared in the previous step, extracting under stirring, adding a phosphoric acid aqueous solution to the obtained raffinate to adjust its pH to 4-4.5 and then using it to prepare iron phosphate;

[0012] S6, precipitation: heating the raffinate from step S5 to 80-90° C. under stirring, adding cetyltrimethylammonium chloride, and stirring for a certain period of time; then adding ferric nitrate solution to cause precipitation reaction; when the pH value of the suspension reaches 1.5-2.5, filtering the suspension, washing the obtained solid with water, and drying to obtain the ferric phosphate product;

[0013] S7. Precipitation treatment: ball-mill the precipitate A and the precipitate B, add them to a hydrochloric acid aqueous solution, stir for a certain period of time, then add ammonia aqueous solution to a pH of 8.5-9 and stir, then add polydodecyl acrylamide acrylic acid, filter to obtain a filtrate; then add phosphoric acid aqueous solution to the filtrate to a pH of 2-3; then add aluminum hydroxide or aluminum oxide and the iron phosphate product prepared in the previous step, stir, filter, dry, and ball-mill.

[0014] Based on the above solution and as a preferred solution of the above solution: in step S1, the phosphoric acid aqueous solution includes 20-30% by mass of analytically pure phosphoric acid, and the mass ratio of phosphating slag particles to phosphoric acid aqueous solution is 1:2-5.

[0015] On the basis of the above scheme and as a preferred scheme of the above scheme: in step S2, the mass ratio of the phosphating slag to the sodium hydroxide solution is 1:5-10.

[0016] On the basis of the above scheme and as a preferred scheme of the above scheme: in step S3, the amount of methenamine used is 0.1-0.2% of the mass of the filtrate, the amount of thiourea used is 0.05-0.1% of the mass of the filtrate, the amount of tetraethylammonium oxalate used is 0.1-0.2% of the mass of the filtrate, and the amount of hydrogen peroxide used is 0.2-0.3% of the mass of the filtrate.

[0017] On the basis of the above scheme and as a preferred scheme of the above scheme: in step S5, the extractant is an organic amine extractant; the organic solvent is one or more of benzene, toluene or kerosene.

[0018] On the basis of the above scheme and as a preferred scheme of the above scheme: in step S6, the amount of cetyltrimethylammonium chloride used is 0.3-0.5% by weight of the raffinate.

[0019] On the basis of the above solution and as a preferred solution of the above solution: in step S7, the amount of polydodecyl acrylamide acrylic acid used is 1-2 g / L.

[0020] The present invention has the beneficial effects of preparing a comprehensive chemical utilization method for phosphating slag using phosphating slag solid waste generated during the steel and metal production process as raw material. Iron phosphate is prepared through pretreatment, alkaline leaching, acid treatment, decolorization, extraction, and precipitation reactions, meeting the requirements of the "Iron Phosphate for Batteries (HG / T 4701-2014)" standard. The zinc-containing precipitate is then processed to prepare a ternary phosphate anti-rust pigment. DETAILED DESCRIPTION

[0021] The present invention is further described below with reference to specific embodiments.

[0022] Example

[0023] The present embodiment relates to a method for comprehensive chemical utilization of phosphating slag, comprising the following steps:

[0024] S1. Phosphating slag pretreatment: The phosphating slag is crushed into particles with a diameter of 100-500 microns, then placed in a phosphoric acid aqueous solution, heated in a water bath, and stirred. After settling, the upper layer of foam is removed, and the slag is passed through a 250-mesh sieve in water. The residue below the sieve is retained, filtered, dried, and set aside. Specifically, in this embodiment, the slag is crushed to an average particle size of approximately 300 microns.

[0025] Furthermore, in step S1, the phosphoric acid aqueous solution includes 20-30% by mass of analytically pure phosphoric acid, and the mass ratio of the phosphating slag particles to the phosphoric acid aqueous solution is 1:2-5. Specifically, in this embodiment, the phosphoric acid aqueous solution includes 25% by mass of analytically pure phosphoric acid, and the mass ratio of the phosphating slag particles to the phosphoric acid aqueous solution is 1:4.

[0026] S2. Alkaline leaching of phosphating slag: The phosphating slag after pretreatment is placed in a 30% by mass sodium hydroxide solution for a certain period of time, and then water is added to adjust the pH value to 10. The reaction is continued for 20 minutes, and the slag is passed through a 500 mesh sieve, and the filtrate and precipitate A are collected.

[0027] Furthermore, in step S2, the mass ratio of the phosphating slag to the sodium hydroxide solution is 1:5-10, specifically 1:8 in this embodiment.

[0028] S3. Acid treatment: hydrochloric acid is added to the filtrate obtained in the previous step to adjust the pH to 6-6.5, and then a solution consisting of hexamethylenetetramine, thiourea, tetraethylammonium oxalate, and hydrogen peroxide is added and stirred for 10 minutes. The mixture is filtered and the filtrate and precipitate B are collected.

[0029] Furthermore, in step S4, the amount of methenamine used is 0.1-0.2% of the mass of the filtrate, the amount of thiourea used is 0.0.5-0.1% of the mass of the filtrate, the amount of tetraethylammonium oxalate used is 0.1-0.2% of the mass of the filtrate, and the amount of hydrogen peroxide used is 0.2-0.3% of the mass of the filtrate; the amount of the polydodecyl acrylamide acrylic acid group used is 0.05-0.08% of the mass of the filtrate. In this embodiment, the amount of methenamine used is 0.1% of the mass of the filtrate, the amount of thiourea used is 0.1% of the mass of the filtrate, the amount of tetraethylammonium oxalate used is 0.1% of the mass of the filtrate, and the amount of hydrogen peroxide used is 0.3% of the mass of the filtrate.

[0030] S4, Decolorization: Activated carbon is added to the filtrate obtained in the previous step, stirred for adsorption, and filtered to collect the filtrate. Furthermore, in step S4, the amount of activated carbon used is 2-3% of the filtrate mass, the adsorption time is 30-45 minutes, and the adsorption temperature is room temperature. In this embodiment, the amount of activated carbon used is 3% of the filtrate mass, and the adsorption time is 15 minutes.

[0031] S5. Extraction: adding an extractant and an organic solution to the liquid prepared in the previous step, extracting under stirring, adding a phosphoric acid aqueous solution to the obtained raffinate to adjust its pH to 4-4.5, and then using it to prepare ferric phosphate.

[0032] Furthermore, in step S5, the extractant is an organic amine extractant; the organic solvent is one or more of benzene, toluene, or kerosene. In this embodiment, the organic solvent is kerosene.

[0033] S6, precipitation: under stirring conditions, the raffinate of step S5 is heated to 80-90° C., and cetyltrimethylammonium chloride is added, and stirred for 15 minutes; then, ferric nitrate solution is added to cause precipitation reaction. When the pH value of the suspension reaches 2, the suspension is filtered, and the obtained solid is washed with water and dried to obtain the ferric phosphate product.

[0034] Further, in the step S6, the amount of cetyltrimethylammonium chloride is 0.3-0.5% of the weight of the raffinate. In the embodiment, the amount of cetyltrimethylammonium chloride is 0.4% of the weight of the raffinate.

[0035] Through analysis, determination and calculation, the product quality meets the standard requirements of HG / T 4701-2014, and the total recovery rate of phosphate in the phosphating residue is 88.6%.

[0036] S7, precipitation treatment: after ball milling, the precipitate A and the precipitate B are added into 20% mass concentration hydrochloric acid aqueous solution, stirred for a certain time, then ammonia water is added to pH 8.5, stirred, then polydodecyl acrylamide acrylic acid is added, and the filtrate is obtained by filtration; then phosphoric acid aqueous solution is added to the filtrate to pH 2; then aluminum hydroxide or aluminum oxide and the prepared iron phosphate product in the previous step are added, stirred, filtered, dried and ball milled. The added aluminum hydroxide is half of the sum of the mass of the precipitate A and the precipitate B. The amount of the added iron phosphate product is one-third of the sum of the mass of the precipitate A and the precipitate B.

[0037] Further, in the step S7, the amount of polydodecyl acrylamide acrylic acid is 1-2 g / L. In the embodiment, the amount is 1.5 g / L.

[0038] The rust-proof coating made of iron phosphate, zinc phosphate and aluminum phosphate is covered on the steel substrate, reacts with the water molecules to generate phosphoric acid, and the phosphoric acid reacts with the steel substrate to generate phosphating film. The phosphating film is an extremely fine and dense film that can be closely combined with the steel substrate, which blocks the further corrosion of water molecules and corrosive substances on the steel substrate. At the same time, because of the presence of phosphate metal ions, an electrochemical resistance is formed with the steel substrate, reducing the electrochemical reaction of the steel substrate, and achieving the purpose of rust prevention.

[0039] The preferred embodiments of the application are described in detail above. It should be understood that those skilled in the art can make many modifications and changes without creative labor based on the concept of the present application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment based on the prior art according to the concept of the present application shall be within the protection scope defined by the claims.

Claims

1. A method for comprehensive chemical utilization of phosphating slag, characterized in that: The steps include: S1. Phosphating slag pretreatment: crush the phosphating slag into particles with a diameter of 100-500 microns, then place the particles in a phosphoric acid aqueous solution, heat in a water bath and stir; after precipitation, remove the upper foam, and pass the slag through a 250-mesh sieve in water, retain the sieve residue, filter it with suction, dry it and set aside; S2. Alkaline leaching of phosphating slag: The phosphating slag after pretreatment is placed in a 30% by mass sodium hydroxide solution for a certain period of time, and then water is added to adjust the pH value to 10-11. The reaction is continued for a certain period of time, and the slag is passed through a 500 mesh sieve, and the filtrate and precipitate A are collected; S3, acid treatment: hydrochloric acid is added to the filtrate obtained in the previous step to adjust the pH value to 6-6.5, and then a solution consisting of hexamethylenetetramine, thiourea, tetraethylammonium oxalate, and hydrogen peroxide is added and stirred for a certain period of time, filtered, and the filtrate and precipitate B are collected; S4, decolorization: adding activated carbon to the filtrate obtained in the previous step, stirring for adsorption, filtering, and collecting the filtrate; S5, extraction: adding an extractant and an organic solvent to the liquid prepared in the previous step, extracting under stirring, adding a phosphoric acid aqueous solution to the obtained raffinate to adjust its pH to 4-4.5 and then using it to prepare iron phosphate; S6, precipitation: heating the raffinate from step S5 to 80-90° C. under stirring, adding cetyltrimethylammonium chloride, and stirring for a certain period of time; then adding ferric nitrate solution to cause precipitation reaction; when the pH value of the suspension reaches 1.5-2.5, filtering the suspension, washing the obtained solid with water, and drying to obtain the ferric phosphate product; S7. Precipitation treatment: ball-mill the precipitate A and the precipitate B, add them to a hydrochloric acid aqueous solution, stir for a certain period of time, then add ammonia aqueous solution to a pH of 8.5-9 and stir, then add polydodecyl acrylamide acrylic acid, filter to obtain a filtrate; then add phosphoric acid aqueous solution to the filtrate to a pH of 2-3; then add aluminum hydroxide or aluminum oxide and the iron phosphate product prepared in the previous step, stir, filter, dry, and ball-mill.

2. The method for comprehensive chemical utilization of phosphating slag according to claim 1, characterized in that: In step S1, the phosphoric acid aqueous solution includes 20-30% by mass of analytically pure phosphoric acid, and the mass ratio of the phosphating slag particles to the phosphoric acid aqueous solution is 1:2-5.

3. The method for comprehensive chemical utilization of phosphating slag according to claim 1, characterized in that: In step S2, the mass ratio of the phosphating slag to the sodium hydroxide solution is 1:5-10.

4. The method for comprehensive chemical utilization of phosphating slag according to claim 1, characterized in that: In step S3, the amount of methenamine used is 0.1-0.2% of the mass of the filtrate, the amount of thiourea used is 0.05-0.1% of the mass of the filtrate, the amount of tetraethylammonium oxalate used is 0.1-0.2% of the mass of the filtrate, and the amount of hydrogen peroxide used is 0.2-0.3% of the mass of the filtrate.

5. The method for comprehensive chemical utilization of phosphating slag according to claim 1, characterized in that: In step S5, the extractant is an organic amine extractant; and the organic solvent is one or more of benzene, toluene or kerosene.

6. The method for comprehensive chemical utilization of phosphating slag according to claim 1, characterized in that: In step S6, the amount of cetyltrimethylammonium chloride used is 0.3-0.5% by weight of the raffinate.

7. The method for comprehensive chemical utilization of phosphating slag according to claim 1, characterized in that: In step S7, the amount of polydodecyl acrylamide acrylic acid used is 1-2 g / L.