Chemical comprehensive utilization treatment method for phosphated residues

Abstract

The invention discloses a chemical comprehensive utilization treatment method for phosphated residues. The chemical comprehensive utilization treatment method comprises the following steps: pre-treating the phosphated residues; the method comprises the following steps: placing phosphated residues in a sodium hydroxide solution, and collecting filtrate and a precipitate A; adding hydrochloric acid into the filtrate, then adding urotropine, thiourea, tetraethylammonium oxalate and hydrogen peroxide acid, and collecting the filtrate and a precipitate B; decoloring is performed; performing extraction; performing precipitation; carrying out ball milling on the precipitate A and the precipitate B, adding a hydrochloric acid aqueous solution, and adding polydodecyl acrylamide acrylic acid to obtain a filtrate; adding a phosphoric acid aqueous solution into the filtrate; and adding aluminum hydroxide or aluminum oxide and an iron phosphate product, stirring, filtering, drying and ball-milling. Phosphated residue solid waste generated in the steel metal product process is used as a raw material, and iron phosphate is prepared through the steps of pretreatment, alkaline leaching, acid treatment, decoloration, extraction, precipitation reaction and the like, so that standard requirements are met. And treating the precipitate containing the zinc element to prepare the ternary phosphate anti-rust pigment.

Description

Technical Field

[0001] The invention relates to a method for chemical comprehensive utilization of 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 the steel surface will produce 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 the 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, the 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 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 comprehensive chemical 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 comprehensive chemical utilization of phosphating slag, which can make better use of the elements in the phosphating slag.

[0005] To solve the above technical problems, the purpose of the present invention is achieved as follows:

[0006] A method for comprehensive chemical utilization of phosphating slag involved in the present invention comprises the following steps:

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

[0008] S2, phosphating slag alkaline leaching: 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, and the reaction is continued for a certain period of time, and then passed through a 500 mesh sieve, and the filtrate and precipitate A are collected;

[0009] S3, acid treatment: add hydrochloric acid to the filtrate obtained in the previous step to adjust the pH value to 6-6.5, then add a solution consisting of urotropine, thiourea, tetraethylammonium oxalate and hydrogen peroxide and stir for a certain period of time, filter, and collect the filtrate and precipitate B;

[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 conditions, adding a phosphoric acid aqueous solution to the obtained raffinate to adjust its pH value to 4-4.5 for preparing iron phosphate;

[0012] S6, precipitation: under stirring conditions, the raffinate of step S5 is heated to 80-90° C., and cetyltrimethylammonium chloride is added, and stirred for a certain period of time; then, a ferric nitrate solution is added to cause a precipitation reaction, and when the pH value of the suspension reaches 1.5-2.5, the suspension is filtered, and the obtained solid is washed with water and dried to obtain the ferric phosphate product;

[0013] S7, precipitation treatment: after ball-milling the precipitate A and the precipitate B, add them into a hydrochloric acid aqueous solution, stir for a certain period of time, then add ammonia water until the pH value is 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 until the pH value is 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] On the basis of the above scheme and as a preferred scheme of the above scheme: 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 urotropine 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 hexadecyltrimethylammonium chloride used is 0.3-0.5% by weight of the raffinate.

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

[0020] The beneficial effects of the present invention are as follows: the present invention relates to a phosphating slag chemical comprehensive utilization treatment method, which uses the phosphating slag solid waste generated in the process of steel and metal products as raw materials, and prepares iron phosphate through pretreatment, alkali leaching, acid treatment, decolorization, extraction and precipitation reaction, etc., to meet the standard requirements of "Iron Phosphate for Batteries (HG / T 4701-2014)". Then, the zinc-containing precipitate is treated to prepare a ternary phosphate antirust pigment. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with specific embodiments.

[0022] Example

[0023] A method for comprehensive chemical utilization of phosphating slag involved in this embodiment comprises the following steps:

[0024] S1. Pretreatment of phosphating slag: crush the phosphating slag into particles with a particle size of 100-500 microns, then place the particles in a phosphoric acid aqueous solution, heat in a water bath and stir; remove the upper foam after precipitation, and pass through a 250-mesh sieve in water, retain the sieve, filter, dry and set aside. Specifically in this embodiment, the average particle size is crushed to about 300 microns.

[0025] Further, 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 to react for a certain period of time, and then water is added to adjust the pH value to 10, and 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, and 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 value to 6-6.5, and then a solution consisting of hexamethylenetetramine, thiourea, tetraethylammonium oxalate and hydrogen peroxide is added and stirred for 10 minutes, filtered, and the filtrate and precipitate B are collected.

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

[0030] S4, decolorization: add activated carbon to the filtrate obtained in the previous step, stir and adsorb, filter, and collect the filtrate. Further, in step S4, the amount of activated carbon is 2-3% of the mass of the filtrate, the adsorption time is 30-45 minutes, and the adsorption temperature is room temperature. In this embodiment, the amount of activated carbon is 3% of the mass of the filtrate, 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 value to 4-4.5 for preparing iron 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 hexadecyltrimethylammonium chloride is added, and stirred for 15 minutes; then, ferric nitrate solution is added to cause precipitation reaction, and 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] Furthermore, in step S6, the amount of hexadecyltrimethylammonium chloride used is 0.3-0.5% by weight of the raffinate. Specifically in this embodiment, the amount of hexadecyltrimethylammonium chloride used is 0.4% by weight of the raffinate.

[0035] After analysis, determination and calculation, the product quality meets the standard requirements of "Iron Phosphate for Batteries (HG / T 4701-2014)", and the total recovery rate of phosphate in the phosphating slag is 88.6%.

[0036] S7, precipitation treatment: After ball milling the precipitate A and precipitate B, add them to a 20% mass concentration hydrochloric acid aqueous solution, stir for a certain period of time, then add ammonia water to a pH value of 8.5 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 value of 2; then add aluminum hydroxide or aluminum oxide and the iron phosphate product prepared in the previous step, stir, filter, dry, and ball mill. The mass of aluminum hydroxide added is half of the sum of the masses of precipitate A and precipitate B. The amount of iron phosphate product added is one third of the sum of the masses of precipitate A and precipitate B.

[0037] Furthermore, in step S7, the amount of polydodecyl acrylamide acrylic acid used is 1-2 g / L, and in this embodiment, 1.5 g / L is selected.

[0038] Anti-rust coating made of iron phosphate, zinc phosphate and aluminum phosphate is covered on the steel substrate, which reacts with the immersed water molecules to form phosphoric acid. The phosphoric acid reacts with the steel substrate to form a phosphate film. The phosphate film is an extremely fine and dense film that can be tightly bonded to the steel substrate, blocking further corrosion of the steel substrate by water molecules and corrosive substances. At the same time, due to the presence of phosphate metal ions, 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 specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for comprehensive chemical utilization of phosphating slag, characterized in that: The steps include: S1. Pretreatment of phosphating slag: crush the phosphating slag into particles with a particle size of 100-500 microns, then place the particles in a phosphoric acid aqueous solution, heat in a water bath and stir; remove the upper foam after precipitation, and pass through a 250-mesh sieve in water, retain the sieve, filter, dry and set aside; S2, phosphating slag alkaline leaching: 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, and the reaction is continued for a certain period of time, and then passed through a 500 mesh sieve, and the filtrate and precipitate A are collected; S3, acid treatment: add hydrochloric acid to the filtrate obtained in the previous step to adjust the pH value to 6-6.5, then add a solution consisting of urotropine, thiourea, tetraethylammonium oxalate and hydrogen peroxide and stir for a certain period of time, filter, and collect the filtrate and precipitate B; 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 solution to the liquid prepared in the previous step, extracting under stirring conditions, adding a phosphoric acid aqueous solution to the obtained raffinate to adjust its pH value to 4-4.5 for preparing iron phosphate; S6, precipitation: under stirring conditions, the raffinate of step S5 is heated to 80-90° C., and cetyltrimethylammonium chloride is added, and stirred for a certain period of time; then, a ferric nitrate solution is added to cause a precipitation reaction, and when the pH value of the suspension reaches 1.5-2.5, the suspension is filtered, and the obtained solid is washed with water and dried to obtain the ferric phosphate product; S7, precipitation treatment: after ball-milling the precipitate A and the precipitate B, add them into a hydrochloric acid aqueous solution, stir for a certain period of time, then add ammonia water until the pH value is 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 until the pH value is 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; 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 hexadecyltrimethylammonium 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.