Mine acid wastewater high-value utilization method

Abstract

The application discloses a mine acid wastewater high-value utilization method, which comprises the steps of concentration, reduction reaction, zinc removal through sulfuration, aluminum removal through neutralization, oxidation, calcium and magnesium removal, oxidation synthesis, aging and washing and the like. The application realizes rapid and efficient utilization of valuable resources such as acid iron, copper and zinc in mine acid wastewater, realizes waste-to-resource, and uses iron in the mine acid wastewater as an iron source for preparing phosphoric iron, thereby effectively solving the mine acid wastewater treatment problem, solving the source and cost bottleneck problem of the iron source for preparing phosphoric iron, and having remarkable economic, social and environmental protection benefits.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial wastewater treatment, and particularly relates to a high-value utilization method of mine acid wastewater. BACKGROUND

[0002] Various mine acid wastewaters generated in mining activities and hydrometallurgical processes contain a large amount of acid, iron, copper, zinc and other heavy metal elements, which have great harmfulness to the environment. The traditional method for treating mine acid wastewater is mainly lime neutralization, which produces a large amount of neutralization slag solid waste, not only wastes valuable metal resources such as iron, copper and zinc, but also occupies the tailings storage capacity and has the risk of secondary pollution.

[0003] Iron phosphate is an excellent material for preparing lithium iron phosphate, a positive material of lithium ion battery. At present, the main iron source for synthesizing iron phosphate involves iron scale, iron powder, iron block, ferrous sulfate, ferric nitrate, ferric chloride and the like, which has high production cost and is in a tight supply and demand relationship, and has obvious limitations. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application aims to provide a high-value utilization method of mine acid wastewater.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0006] A high-value utilization method of mine acid wastewater, comprising the following steps:

[0007] S1, concentrating: after the mine acid wastewater is precisely filtered to remove suspended solids, the filtrate is concentrated to obtain a concentrated solution;

[0008] S2, reduction reaction: an excess of iron powder or industrial scrap iron is added to the concentrated solution for reduction reaction, and after the reaction is completed, solid-liquid separation is performed, the obtained filter residue is separated by magnetic separation to obtain elemental copper and unreacted iron powder, and the recovered iron powder is returned for reduction reaction with the concentrated solution;

[0009] S3, zinc removal by sulfidation: sulfide is added to the filtrate obtained in step S2 for zinc removal by sulfidation, and after the stirring reaction is completed, solid-liquid separation is performed to obtain zinc sulfide residue;

[0010] S4, aluminum removal by neutralization: ferrous hydroxide is added to the filtrate obtained by solid-liquid separation in step S3 for aluminum removal by neutralization, and after the stirring reaction is completed, precise filtration is performed, and the filter residue obtained by filtration is ferrous hydroxide residue, which is returned for aluminum removal by neutralization;

[0011] S5, oxidation: hydrogen peroxide is added to the filtrate obtained by precise filtration in step S4 for oxidation;

[0012] S6, calcium and magnesium removal: iron fluoride is added to the solution obtained after oxidation in step S5 to remove calcium and magnesium, and the reaction is stirred and heated. After the reaction is completed, solid-liquid separation is performed, and the filtrate is a ferric sulfate filtrate. The filter residue reacts with acid to produce hydrofluoric acid, which is introduced into the prepared ferric sulfate solution. After solid-liquid separation, the obtained iron fluoride is used for calcium and magnesium removal;

[0013] S7, oxidation synthesis: phosphorus source is added to the ferric sulfate filtrate obtained in step S6, and the reaction is stirred and heated to oxidize and synthesize a crude ferric phosphate product. After the reaction is completed, solid-liquid separation is performed to obtain the crude ferric phosphate product.

[0014] S8, aging and washing: phosphoric acid is added to the crude ferric phosphate product obtained in step S7 to adjust the slurry, and the reaction is stirred and heated to age. After the reaction is completed, solid-liquid separation is performed, and the filter residue is washed and dried to obtain a ferric phosphate product.

[0015] Further, in step S1, the filtrate is pumped into one or more of an electrodialysis system or an MVR system for high-concentration concentration, and the concentration of iron ions in the obtained concentrated solution is 25-100 g / L.

[0016] Further, in step S2, the temperature of the reduction reaction is 30-60℃, and the reaction time is 0.5-2.5h.

[0017] Further, in step S3, the sulfide is one or more of sodium hydrosulfide, sodium sulfide, and hydrogen sulfide, and the amount of the sulfide is 1.5-3 times the theoretical amount of the sulfide calculated based on the concentration of zinc ions in the filtrate obtained in step S2.

[0018] Further, in the neutralization and aluminum removal of step S4, the end point pH is controlled to be 5-6.5.

[0019] Further, in step S5, the molar ratio of H2O2 in the hydrogen peroxide to ferrous ions in the solution obtained after oxidation in step S5 is 0.55-0.65.

[0020] Further, in step S6, the temperature of the stirring and heating reaction is 65-90℃, and the reaction time is 1.5-2.5h.

[0021] Further, in step S6, the amount of iron fluoride is 2-3.5 times the theoretical amount of iron fluoride calculated based on the concentration of calcium and magnesium ions in the solution obtained after oxidation in step S5; the acid used to react with the filter residue is one of sulfuric acid, hydrochloric acid, or nitric acid; and the concentration of the ferric sulfate solution obtained by solid-liquid separation is 50-300 g / L.

[0022] Further, in step S7, the phosphorus source is one or more of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium phosphate, the molar ratio of Fe:P is 1:(0.95-1.05), the reaction temperature is 65 DEG C, and ammonia water is added to adjust the reaction pH to 1.8-2.0.

[0023] Further, in step S8, the concentration of phosphoric acid used is 0.03-0.3 mol / L, the aging reaction time is 1-3.5 h, and the aging temperature is 95 DEG C.

[0024] The present application has the following advantages:

[0025] 1) The present application provides a process route and technical method for high-value utilization of mine acid wastewater, the synthesized iron phosphate product meets the product standard requirements of the battery-grade iron phosphate (HG / T 4701-2014) in the chemical industry standard, in addition, zinc sulfide and copper elemental product are obtained, realizing the resourceization and high-value recovery of valuable metals such as copper and zinc, and avoiding the resource waste of the traditional neutralization process of mine acid wastewater.

[0026] 2) The present application makes full use of the acid iron resources in mine acid wastewater, changes them into high-value iron phosphate products, realizes the combination of traditional mine wet smelting and battery raw material preparation process, expands the raw material source of iron phosphate production, and greatly saves the treatment cost of mine acid wastewater treatment.

[0027] 3) The present application uses iron fluoride as a reagent in calcium and magnesium removal, avoids the introduction of sodium salt, and further realizes the enrichment and recycling of iron in the solution.

[0028] 4) The present application realizes the recycling of filter residues in the reduction reaction and neutralization and aluminum removal steps, avoids the generation of new solid waste, and can further reduce the production cost.

[0029] In summary, the present application realizes the rapid and efficient utilization of valuable resources such as acid iron, copper and zinc in mine acid wastewater, realizes the transformation of waste into treasure, and uses iron in mine acid wastewater as the iron source for preparing iron phosphate, which not only effectively solves the problem of mine acid wastewater treatment, but also solves the source and cost bottleneck problem of iron source for preparing iron phosphate, and has significant economic, social and environmental benefits. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The method flowchart of each embodiment of the present application. DETAILED DESCRIPTION

[0031] The present application will be further described below with reference to the accompanying drawings, and it should be noted that the present embodiment is based on the technical solution, and detailed implementation and specific operation process are given, but the protection scope of the present application is not limited to the present embodiment.

[0032] Example 1

[0033] The composition of the mine acid wastewater in the wet production process of a certain copper sulfide mine mainly includes: Cu 2+ 133 mg / L, TFe 8.98 g / L, Fe 2+ 20 mg / L, Zn 2+ 290.8 mg / L, As 48.09 mg / L, Al 3+ 1.42 g / L, Ca 2+ 362.2 mg / L, Mg 2+ 59.94 mg / L, Mn 2+ 29.46 mg / L, H2SO4 8.96 mg / L, pH = 1.15.

[0034] As Figure 1 shown, the mine acid wastewater high-value utilization method of the present embodiment includes the following steps:

[0035] (1) Deep concentration: After removing the suspended solids by precision filtration of the above mine acid wastewater, the filtrate is pumped into an electrodialysis system for high-fold concentration, and a concentrated solution with an iron ion concentration of 100 g / L is obtained.

[0036] (2) Reduction reaction: 2.5 times the theoretical amount of iron powder, i.e. 215 g / L of iron powder, is added to the concentrated solution of step (1) for reduction reaction, heated to 60°C, and stirred for 2.5 h. After the reaction is completed, solid-liquid separation is performed, the obtained filter residue is separated by magnetic separation to separate copper and unreacted iron powder, the recovered iron powder is recycled in this step, and copper product with a copper content of 99.2% is also recovered, which is sold externally.

[0037] (3) Zinc removal by sulfidation: Sodium hydrosulfide is added to the filtrate obtained in step (2) for zinc removal by sulfidation, and after stirring for 1 h, solid-liquid separation is performed to obtain zinc sulfide residue with a zinc content of 61.7%. The amount of sodium hydrosulfide added is 1.5 times the theoretical amount of sodium hydrosulfide calculated based on the concentration of zinc ions in the solution, i.e. 4 g / L of sodium hydrosulfide.

[0038] (4) Neutralization and aluminum removal: Ferrous hydroxide is added to the filtrate obtained in step (3) for neutralization and aluminum removal, and the final pH is controlled at 5. After stirring for 1 h, precision filtration is performed after the reaction is completed. The filter residue obtained by filtration is mainly ferrous hydroxide residue, which is recycled in this step.

[0039] (5) Oxidation: Hydrogen peroxide is added to the filtrate obtained in step (4) for oxidation, and the amount of hydrogen peroxide used is 0.65 times the molar ratio of H2O2 to ferrous ions in the filtrate.

[0040] (6) Removing calcium and magnesium: Iron fluoride is added to the solution obtained in step (5), heated to 90°C, and stirred for 2.5 h. After the reaction is completed, solid-liquid separation is performed to obtain a 300 g / L iron sulfate filtrate. The amount of iron fluoride added is 2 times the theoretical amount of iron fluoride calculated based on the concentration of calcium and magnesium ions in the solution. The filter residue is reacted with sulfuric acid to produce hydrofluoric acid, which is introduced into the prepared iron sulfate solution to obtain 99% iron fluoride, which is recycled in this step.

[0041] (7) Oxidative synthesis: Ammonium hydrogen phosphate is added to the iron sulfate filtrate obtained in step (6) to oxidatively synthesize a crude iron phosphate product at 65°C, with a molar ratio of Fe:P of 1:1.05, and ammonia water is added to adjust the pH of the reaction to 2. After the reaction is completed, solid-liquid separation is performed to obtain the crude iron phosphate product.

[0042] (8) Aging and washing: The crude iron phosphate product obtained in step (7) is slurried with 0.3 mol / L phosphoric acid, heated to 95°C, and stirred for aging. The aging reaction time is 1 h. After the reaction is completed, solid-liquid separation is performed, and washing and drying are performed to obtain the iron phosphate product.

[0043] The main components of the copper residue, zinc sulfide, and iron phosphate product formed are shown in Tables 1 and 2.

[0044] Example 2

[0045] As shown in Table 1, the composition of the mine acid wastewater in the wet production process of a certain copper sulfide mine is the same as that of Example 1. Figure 1

[0046] The mine acid wastewater high-value utilization method of this example includes the following steps:

[0047] (1) Deep concentration: A certain amount of mine acid wastewater is precisely filtered to remove suspended solids, and the filtrate is pumped into an electrodialysis system for high-concentration concentration to obtain a concentrated solution with an iron ion concentration of 50 g / L.

[0048] (2) Reduction reaction: 2 times the theoretical amount of iron powder, i.e., 136 g / L of iron powder, is added to the concentrated solution of step (1) for reduction reaction, heated to 45°C, and stirred for 1.5 h. After the reaction is completed, solid-liquid separation is performed. The filter residue is separated by magnetic separation to separate copper and unreacted iron powder. The recovered iron powder is recycled in this step. Copper with a copper content of 99.5% is also recovered, and the product is sold externally.

[0049] (3) Zinc removal by sulfidation: Sodium hydrosulfide is added to the filtrate obtained in step (2) for zinc removal by sulfidation. After stirring for 1 h, solid-liquid separation is performed to obtain zinc sulfide residue with a zinc content of 62.1%. The amount of sodium hydrosulfide added is 2 times the theoretical amount of sodium hydrosulfide calculated based on the concentration of zinc ions in the filtrate, i.e., 2.6 g / L of sodium hydrosulfide.​

[0050] (4) Neutralization and aluminum removal: ferrous hydroxide is added to the filtrate obtained in step (3) for neutralization and aluminum removal, the end point pH is controlled at 6, the reaction is stirred for 1 h, and after the reaction is completed, precision filtration is performed. The filter residue obtained is mainly ferrous hydroxide residue, and the ferrous hydroxide residue is recycled in this step.

[0051] (5) Oxidation: hydrogen peroxide is added to the filtrate obtained in step (4) for oxidation, and the amount of hydrogen peroxide used is 0.6 times the molar amount of ferrous ions in the solution.

[0052] (6) Calcium and magnesium removal: ferrous fluoride is added to the filtrate obtained in step 5, heated to 80°C, and stirred for 2 h. After the reaction is completed, solid-liquid separation is performed to obtain a 150 g / L ferrous sulfate filtrate. The amount of ferrous fluoride added is 3 times the theoretical amount of ferrous fluoride calculated based on the concentration of calcium and magnesium ions in the solution. The filter residue is reacted with sulfuric acid to produce hydrofluoric acid, which is introduced into the prepared ferrous sulfate solution to obtain ferrous fluoride with a content of 99%, which is recycled in this step.

[0053] (7) Oxidation synthesis: ammonium dihydrogen phosphate is added to the ferrous sulfate filtrate obtained in step (6) to oxidize and synthesize crude ferrous phosphate product at 65°C, the molar ratio of Fe to P is 1:1, and ammonia water is added to adjust the reaction pH to 1.9. After the reaction is completed, solid-liquid separation is performed to obtain the crude ferrous phosphate product.

[0054] (8) Aging and washing: 0.1 mol / L phosphoric acid is added to the crude ferrous phosphate product obtained in step (7) to adjust the slurry, heated to 95°C and stirred for aging, the aging reaction time is 2 h, after the reaction is completed, solid-liquid separation is performed, and washing and drying are performed to obtain the ferrous phosphate product.

[0055] The main components of the copper slag, zinc sulfide, and ferrous phosphate product formed are shown in Tables 1 and 2.

[0056] Example 3

[0057] As Figure 1 shown, the composition of the mine acid wastewater in the wet production process of a certain copper sulfide mine is the same as that of Example 1.

[0058] The high-value utilization method of the mine acid wastewater of this example includes the following steps:

[0059] (1) Deep concentration: after precision filtration to remove suspended solids, the filtrate is pumped into the MVR system for high-concentration concentration to obtain a concentrated solution with an iron ion concentration of 25 g / L.

[0060] (2) Reduction reaction: 1.5 times the theoretical amount of iron powder, i.e. 50 g / L of iron powder, was added to the concentrated solution of step (1) to perform the reduction reaction, heated to 30°C, and stirred for 0.5 h. After the reaction was completed, solid-liquid separation was performed, the obtained filter residue was separated by magnetic separation to obtain elemental copper and unreacted iron powder, the recovered iron powder was recycled in this step, and elemental copper product with a copper content of 99.7% was recovered and sold.

[0061] (3) Zinc removal by sulfidation: sodium hydrosulfide was added to the filtrate obtained in step (2) to remove zinc by sulfidation. After stirring for 1 h, solid-liquid separation was performed to obtain zinc sulfide residue with a zinc content of 67.9%. The amount of sodium hydrosulfide added was 3 times the theoretical amount of sodium hydrosulfide calculated based on the concentration of zinc ions in the solution, i.e. 2 g / L of sodium hydrosulfide.

[0062] (4) Neutralization and aluminum removal: ferrous hydroxide was added to the filtrate obtained in step (3) to perform neutralization and aluminum removal, and the final pH was controlled at 6.5. After stirring for 1 h, precision filtration was performed, and the filter residue obtained was mainly ferrous hydroxide residue, which was recycled in this step.

[0063] (5) Oxidation: hydrogen peroxide was added to the filtrate obtained in step (4) to perform oxidation, and the amount of hydrogen peroxide used was a molar ratio of H2O2 to ferrous ions in the solution of 0.55.

[0064] (6) Calcium and magnesium removal: iron fluoride was added to the filtrate obtained in step (5), heated to 65°C, and stirred for 1.5 h. After the reaction was completed, solid-liquid separation was performed to obtain 50 g / L of iron sulfate filtrate. The amount of iron fluoride added was 2 times the theoretical amount of iron fluoride calculated based on the concentration of calcium and magnesium ions in the solution. The filter residue was reacted with sulfuric acid to produce hydrofluoric acid, which was introduced into the prepared iron sulfate solution to obtain 99% iron fluoride, which was recycled in this step.

[0065] (7) Oxidation synthesis: diammonium hydrogen phosphate was added to the iron sulfate filtrate obtained in step (6) to perform oxidation synthesis of crude iron phosphate product at 65°C, with a molar ratio of Fe:P of 1:0.95, and ammonia water was added to adjust the reaction pH to between 1.8. After the reaction was completed, solid-liquid separation was performed to obtain the crude iron phosphate product.

[0066] (8) Aging and washing: 0.03 mol / L phosphoric acid was added to the crude iron phosphate product obtained in step (7) to adjust the slurry, heated to 95°C, and stirred for aging. The aging reaction time was 3.5 h, and after the reaction was completed, solid-liquid separation was performed, and washing and drying were performed to obtain the iron phosphate product.

[0067] The main components of the copper residue, zinc sulfide, and iron phosphate products formed are shown in Tables 1 and 2.

[0068] Table 1 Copper slag, zinc sulphide product indicators (%)

[0069] Product Copper powder Zinc sulfide Example 1 99.2 61.7 Example 2 99.5 62.1 Example 3 99.7 67.9

[0070] Table 2 Iron phosphate product indicators (mg / L) of synthesis

[0071]

[0072] For those skilled in the art, various corresponding changes and modifications can be made according to the above technical solutions and concepts, and all these changes and modifications should be included in the protection scope of the claims of the present application.

Claims

1. A mine acid wastewater high-value utilization method, characterized in that, The method comprises the following steps: S1, concentrating: after removing suspended solids from the mine acid wastewater by precision filtration, the filtrate is concentrated to obtain a concentrated solution; S2, reduction reaction: an excess of iron powder or industrial scrap iron is added to the concentrated solution for reduction reaction, and after the reaction is completed, solid-liquid separation is performed to obtain filter residue, which is separated by magnetic separation to obtain elemental copper and unreacted iron powder, and the recovered iron powder is returned for reduction reaction with the concentrated solution; S3, zinc removal by sulfidation: sulfide is added to the filtrate obtained in step S2 for zinc removal by sulfidation, and after the stirring reaction is completed, solid-liquid separation is performed to obtain zinc sulfide residue; S4, neutralization and aluminum removal: ferrous hydroxide is added to the filtrate obtained by solid-liquid separation in step S3 for neutralization and aluminum removal, and after the stirring reaction is completed, precision filtration is performed, and the filter residue obtained by filtration is ferrous hydroxide residue, which is returned for neutralization and aluminum removal; S5, oxidation: hydrogen peroxide is added to the filtrate obtained by precision filtration in step S4 for oxidation; S6, calcium and magnesium removal: iron fluoride is added to the solution obtained after oxidation in step S5 for calcium and magnesium removal, and after heating and stirring reaction, solid-liquid separation is performed, and the filtrate is iron sulfate filtrate; the filter residue reacts with acid to produce hydrofluoric acid, which is introduced into the prepared iron sulfate solution, and after solid-liquid separation, the obtained iron fluoride is returned for calcium and magnesium removal; S7, oxidation synthesis: a phosphorus source is added to the iron sulfate filtrate obtained in step S6 for heating and stirring reaction, and a crude iron phosphate product is obtained by oxidation synthesis, and after the reaction is completed, solid-liquid separation is performed to obtain the crude iron phosphate product; S8, aging and washing: phosphoric acid is added to the crude iron phosphate product obtained in step S7 for slurry preparation, and after heating and stirring aging, solid-liquid separation is performed, and the filter residue is washed and dried to obtain an iron phosphate product.

2. The mine acidic wastewater high-value utilization method according to claim 1, characterized in that, In step S1, the filtrate is pumped into one or more of an electrodialysis system or an MVR system for high-concentration, and the concentration of iron ions in the obtained concentrated solution is 25-100 g / L.

3. The mine acid wastewater high-value utilization method according to claim 1, characterized in that, In step S2, the temperature of the reduction reaction is 30-60℃, and the reaction time is 0.5-2.5 h.

4. The mine acid wastewater high-value utilization method according to claim 1, characterized in that, In step S3, the sulfide is one or more of sodium hydrosulfide, sodium sulfide, and hydrogen sulfide, and the amount of the sulfide is 1.5-3 times the theoretical amount of the sulfide calculated based on the concentration of zinc ions in the filtrate obtained in step S2.

5. The mine acid wastewater high-value utilization method according to claim 1, characterized in that, In step S4, the final pH is controlled to be 5-6.

5.

6. The mine acid wastewater high-value utilization method according to claim 1, characterized in that, In step S5, the molar ratio of H2O2 in the hydrogen peroxide to ferrous ions in the solution obtained after oxidation in step S5 is 0.55-0.

65.

7. The mine acidic wastewater high-value utilization method according to claim 1, characterized in that, In step S6, the temperature of the heating and stirring reaction is 65-90℃, and the reaction time is 1.5-2.5 h.

8. The mine acid wastewater high-value utilization method according to claim 1, characterized in that, In step S6, the amount of iron fluoride is 2-3.5 times the theoretical amount of iron fluoride calculated based on the concentration of calcium and magnesium ions in the solution obtained after oxidation in step S5; the acid used to react with the filter residue is one of sulfuric acid, hydrochloric acid, or nitric acid; and the concentration of the iron sulfate solution obtained by solid-liquid separation is 50-300 g / L.

9. The mine acid wastewater high-value utilization method according to claim 1, characterized in that, In step S7, the phosphorus source is one or more of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and ammonium phosphate, and the molar ratio of Fe:P is 1:(0.95-1.05); the reaction temperature is 65℃, and ammonia water is added to adjust the reaction pH to 1.8-2.

0.

10. The mine acid wastewater high-value utilization method according to claim 1, characterized in that, The concentration of phosphoric acid used in step S8 is 0.03-0.3 mol / L, the aging reaction time is 1-3.5 h, and the aging temperature is 95°C.

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