Method for recycling high-arsenic copper waste acid

Abstract

The invention discloses a method for recycling high-arsenic copper waste acid, which comprises the steps of copper removal, arsenic removal and post-treatment, and specifically comprises the following steps: adding Na2S. 9H2O into high-arsenic copper waste acid to be treated, stirring and reacting for 20-40 minutes at normal temperature, carrying out suction filtration to obtain copper slag a and copper-removed liquid b, and carrying out copper recovery on the copper slag a; the pH value of the decoppered liquid b is adjusted to 1-5, then Na2S. 9H2O is added to react for 20-40 min at the normal temperature, and arsenic slag c and arsenic-removed liquid d are obtained through suction filtration; water is added into the arsenic slag c for size mixing, and then a high-pressure kettle is used for stabilizing treatment to achieve harmlessness of arsenic. According to the method, recycling of copper in the high-arsenic copper waste acid and volume reduction and weight reduction treatment of arsenic can be efficiently achieved in a short process, the service life of a rigid landfill can be remarkably prolonged, the landfill amount of the rigid landfill can be remarkably increased, the landfill cost is greatly reduced, and the method has important significance on improving the clean and safe production technology level of enterprises.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for recycling high-arsenic copper waste acid. Background Art

[0002] The waste acid produced by smelting and other industries usually contains more than 5% sulfuric acid, as well as a large amount of heavy metals such as As, Cu, Pb and high-concentration pollutants. The content of arsenic and copper ranges from several hundred milligrams per liter to several thousand milligrams per liter, and arsenic is even as high as 30g / L or more. If the waste acid is discharged without treatment, it will pose a serious threat to the environment and human health, and the valuable metals and acids in it cannot be recycled.

[0003] Under the increasingly severe demand for environmental protection and resource recycling, efficient impurity removal and recycling of polluted acid has become a technical problem that needs to be solved urgently. In order to recycle sulfuric acid in polluted acid in industry, the sulfidation method is often used to remove impurities such as copper, arsenic, cadmium, and lead, and then evaporation, concentration, and air stripping to remove fluorine and chlorine can obtain recyclable sulfuric acid. During sulfidation, a large amount of copper in high-arsenic copper polluted acid will enter the sulfidation slag along with arsenic. At present, arsenic has no great recovery value, but direct landfill of sulfidation slag not only has great safety hazards, but also causes high-content copper loss in the slag. Therefore, it is very necessary to develop a method that can solve the above technical problems. Summary of the invention

[0004] The object of the present invention is to provide a method for recycling high-arsenic copper waste acid.

[0005] The object of the present invention is achieved in that the method for recycling high-arsenic copper waste acid comprises the steps of copper removal, arsenic removal and post-treatment, specifically comprising: A. Copper removal: Add Na2S.9H2O to the high-arsenic copper waste acid to be treated and stir the reaction at room temperature for 20-40 minutes. After filtration, copper slag a and copper removal liquid b are obtained. Copper is recovered from the copper slag a. B. Arsenic removal: adjust the pH value of the copper removal solution b to 1-5, then add Na2S.9H2O and react at room temperature for 20-40 minutes, obtain arsenic residue c and arsenic removal solution d by suction filtration, and send the arsenic removal solution d to subsequent evaporation and concentration to remove fluorine and chlorine to obtain recyclable sulfuric acid; C. Post-treatment: After adding water to the arsenic slag c, a stabilization reaction is carried out in an autoclave to achieve harmless treatment of arsenic.

[0006] The raw material of the present invention is high-arsenic copper waste acid containing 8-13 g / L arsenic and 1.5-2.5 g / L copper. ① Utilizing the different solubility products and potentials of CuS and As2S3, the method of "first sulfidation slag removal for copper, then sulfidation slag removal for arsenic" is adopted to slag to obtain copper slag and arsenic slag respectively. The copper slag is returned to the smelting system for recycling, and the arsenic slag is subjected to the next step of treatment. ② The arsenic slag realizes the change of crystal structure and morphological characteristics under high temperature and high pressure, achieves the purpose of stabilization and volume reduction, improves its stability in the environment, is convenient for storage, and can also be rigidly landfilled.

[0007] The present invention can efficiently realize the recovery and utilization of copper in high-arsenic copper waste acid and the harmless treatment of arsenic in a short process, can significantly extend the service life and landfill volume of rigid landfills, greatly reduce landfill costs, and is of great significance to improving the clean and safe production technology level of enterprises.

[0008] To achieve the above object, the present invention is implemented through the following technical solutions: ① The present invention first adds 1.2 times the theoretical amount of Na2S.9H2O to the waste acid at room temperature to remove copper. Since the arsenic content in the waste acid is much greater than the copper content, As2S3 precipitation will be generated while CuS is generated. The copper slag contains 15% to 25% copper and 11% to 20% arsenic. Although the arsenic content is relatively high, it does not affect the recovery of the copper slag. The main chemical reaction in this step is: Cu 2+ +S 2- =CuS↓ ② After copper removal, add 1.2 times the theoretical amount of Na2S.9H2O to the liquid for sulfide arsenic removal at room temperature. This step generates As2S3 precipitation, and the arsenic slag contains 25%~45% arsenic and 0.5%~1.5% copper. The arsenic removal rate can reach more than 99%, and the copper loss can reach less than 5%, which better realizes the removal of arsenic in the waste acid and the recovery of copper. The main chemical reaction of this step is: As 3+ +S 2- =As2S3↓ ③ Arsenic slag with a water content of 65-75% is stabilized and reduced in volume and weight using an autoclave after slurry adjustment. Arsenic slag changes its crystal structure and morphology under high temperature and high pressure, transforming from the original colloidal precipitated particles into large particles of sand or block, with reduced water absorption and increased density. It can reduce volume by more than 80% and weight by more than 70%, making it easier to store and rigidly landfill. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0010] The present invention is further described below in conjunction with the embodiments, but the present invention is not limited in any way. Any changes or substitutions made based on the teachings of the present invention belong to the protection scope of the present invention.

[0011] The method for recycling high-arsenic copper waste acid of the present invention comprises the steps of copper removal, arsenic removal and post-treatment, specifically comprising: A. Copper removal: Add Na2S.9H2O to the high-arsenic copper waste acid to be treated and stir the reaction at room temperature for 20-40 minutes. After filtration, copper slag a and copper removal liquid b are obtained. Copper is recovered from the copper slag a. B. Arsenic removal: adjust the pH value of the copper removal solution b to 1-5, then add Na2S.9H2O and react at room temperature for 20-40 minutes, and obtain arsenic slag c with a water content of 65-75% and arsenic removal solution d by suction filtration. The arsenic removal solution d is sent to subsequent evaporation and concentration to remove fluorine and chlorine, and then obtain sulfuric acid that can be recycled; C. Post-treatment: After adding water to the arsenic slag c to prepare the slurry, a stabilization reaction is carried out in an autoclave to achieve harmless treatment of arsenic.

[0012] The amount of Na2S.9H2O used in step A is 1 to 1.5 times the theoretical amount of high-arsenic copper waste acid to be treated.

[0013] The dosage of Na2S.9H2O is 1.2 times the theoretical dosage of the high-arsenic copper waste acid to be treated.

[0014] The amount of Na2S.9H2O used in step B is 1 to 1.5 times the theoretical amount of arsenic removal from liquid B after copper removal.

[0015] The dosage of Na2S.9H2O is 1.2 times the theoretical dosage of the high-arsenic copper waste acid to be treated.

[0016] The amount of water added in step C is 3 to 5 times the mass of arsenic slag c.

[0017] The temperature of the stabilization reaction in step C is 180-250°C.

[0018] The temperature of the stabilization reaction is 200-230°C.

[0019] The stabilization reaction time in step C is 2.5 to 4 hours.

[0020] The high-arsenic-copper waste acid to be treated contains 8-13 g / L arsenic and 1.5-2.5 g / L copper.

[0021] The present invention is further described below with specific implementation cases: Example 1 To 600 ml of waste acid containing 9.30 g / L As and 2.49 g / L Cu, add 1.2 times the theoretical amount of Na2S.9H2O at room temperature and stir thoroughly for 30 minutes. Filter and obtain copper slag containing 24.76% copper and 12.25% arsenic, which can be returned to the smelting furnace.

[0022] The pH value of the decoppered liquid was adjusted to 1-5, Na2S.9H2O was added and stirred sufficiently, and PAM flocculant was added after the reaction for 30 minutes to generate a precipitate. After obvious flocculation, it was filtered to produce arsenic slag containing 27.83% arsenic and 1.51% copper.

[0023] The arsenic slag was prepared with a solid-liquid ratio of 1:3, placed in an autoclave for heating and stirring, and reacted at 200°C for 3.5 hours. After cooling, it was taken out and filtered for solid-liquid separation. The obtained solid was 70.45% lighter and 85.33% less in volume than the raw material.

[0024] Example 2 To 600 ml of waste acid containing 12.23 g / L As and 1.83 g / L Cu, add 1.2 times the theoretical amount of Na2S.9H2O at room temperature and stir thoroughly for 30 minutes. Filter and obtain copper slag containing 21.76% copper and 14.72% arsenic, which can be returned to the smelting furnace.

[0025] The pH value of the decoppered liquid was adjusted to 1-5, Na2S.9H2O was added and stirred sufficiently, and PAM flocculant was added after the reaction for 30 minutes to generate a precipitate. After obvious flocculation, it was filtered to produce arsenic slag containing 32.45% arsenic and 0.93% copper.

[0026] The arsenic slag was prepared with a solid-liquid ratio of 1:5, placed in an autoclave for heating and stirring, reacted at 220°C for 3.5 hours, and then taken out and filtered after cooling for solid-liquid separation. The obtained solid was 71.38% lighter and 86.82% less in volume than the raw material.

[0027] Example 3 To 600 ml of waste acid containing 8.63 g / L As and 2.02 g / L Cu, add 1.2 times the theoretical amount of Na2S.9H2O at room temperature and stir thoroughly for 30 minutes. Filter and obtain copper slag containing 24.68% copper and 9.36% arsenic, which can be returned to the smelting furnace.

[0028] The pH value of the decoppered liquid was adjusted to 1-5, Na2S.9H2O was added and stirred sufficiently, and PAM flocculant was added after the reaction for 30 minutes to generate a precipitate. After obvious flocculation, it was filtered to produce arsenic slag containing 12.96% arsenic and 0.46% copper.

[0029] The arsenic slag was prepared with a solid-liquid ratio of 1:3, placed in an autoclave for heating and stirring, reacted at 230°C for 3 hours, and then taken out and filtered after cooling for solid-liquid separation. The obtained solid was 72.66% lighter and 83.45% less in volume than the raw material.

Claims

1. A method for recycling high-arsenic copper waste acid, characterized in that: The method for recycling high-arsenic copper waste acid includes copper removal, arsenic removal and post-treatment steps, specifically including: A. Copper removal: Add Na2S.9H2O to the high-arsenic copper waste acid to be treated and stir the reaction at room temperature for 20-40 minutes. After filtration, copper slag a and copper removal liquid b are obtained. Copper is recovered from the copper slag a. B. Arsenic removal: adjust the pH value of the copper removal solution b to 1-5, then add Na2S.9H2O and react at room temperature for 20-40 minutes, obtain arsenic residue c and arsenic removal solution d by suction filtration, and send the arsenic removal solution d to subsequent evaporation and concentration to remove fluorine and chlorine to obtain recyclable sulfuric acid; C. Post-treatment: After adding water to the arsenic slag c, a stabilization reaction is carried out in an autoclave to achieve arsenic volume and quantity reduction treatment.

2. The method for recycling high-arsenic copper waste acid according to claim 1, characterized in that: The amount of Na2S.9H2O used in step A is 1 to 1.5 times the theoretical amount of high-arsenic copper waste acid to be treated.

3. The method for recycling high-arsenic copper waste acid according to claim 1 or 2, characterized in that: The dosage of Na2S.9H2O is 1.2 times the theoretical dosage of the high-arsenic copper waste acid to be treated.

4. The method for recycling high-arsenic copper waste acid according to claim 1, characterized in that: The amount of Na2S.9H2O used in step B is 1 to 1.5 times the theoretical amount of arsenic removal from liquid B after copper removal.

5. The method for recycling high-arsenic copper waste acid according to claim 1 or 4, characterized in that: The dosage of Na2S.9H2O is 1.2 times the theoretical dosage of the high-arsenic copper waste acid to be treated.

6. The method for recycling high-arsenic copper waste acid according to claim 1, characterized in that: The amount of water added in step C is 3 to 5 times the mass of arsenic slag c.

7. The method for recycling high-arsenic copper waste acid according to claim 1, characterized in that: The temperature of the stabilization reaction in step C is 180-250°C.

8. The method for recycling high-arsenic copper waste acid according to claim 1 or 7, characterized in that: The temperature of the stabilization reaction is 200-230°C.

9. The method for recycling high-arsenic copper waste acid according to claim 1, characterized in that: The stabilization reaction time in step C is 2.5 to 4 hours.

10. The method for recycling high-arsenic copper waste acid according to claim 1, characterized in that: The high-arsenic-copper waste acid to be treated contains 8-13 g / L arsenic and 1.5-2.5 g / L copper.

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