Method for recovering valuable elements by synergistically using high-arsenic alkaline wastewater and black copper mud

Abstract

The invention belongs to the field of metallurgical technology, and specifically relates to a method for synergistically recovering valuable elements from high-arsenic alkaline wastewater and black copper mud, comprising the following steps: S1. adding black copper mud to high-arsenic alkaline wastewater, and after reaction, solid-liquid separation to obtain arsenic-rich liquid and copper slag; S2. adding sulfuric acid to the arsenic-rich liquid obtained in step S1, and after reaction, obtaining arsenic trioxide slag and low-arsenic wastewater; S3. evaporating and concentrating the low-arsenic wastewater obtained in step S2 to obtain sodium sulfate and evaporation mother liquor. The invention combines the chemical properties of high-arsenic alkaline wastewater and black copper mud, and jointly treats the two to recover valuable elements such as arsenic and copper, thereby reducing the production cost of separately treating high-arsenic alkaline wastewater and black copper mud, achieving the purpose of "using waste to treat waste and turning waste into treasure", avoiding the problem of heavy metal pollution in the reuse process, and having the advantages of short process flow, high metal recovery rate, low treatment cost, etc.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and relates to a method for collaboratively recovering valuable elements from non-ferrous smelting wastewater and solid waste, and specifically relates to a method for collaboratively recovering valuable elements from high-arsenic alkaline wastewater and black copper mud. Background Art

[0002] The high-arsenic antimony smoke produced during the non-ferrous smelting process is generally treated by oxygen pressure alkaline leaching. Arsenic is dissolved in the solution in the form of sodium arsenate, and antimony remains in the slag to achieve arsenic-antimony separation. The solution contains 20-45 g / L of arsenic and 30-60 g / L of NaOH, which is a typical high-arsenic alkaline wastewater. High-arsenic alkaline wastewater is generally treated by ferrous sulfate precipitation, which produces a large amount of arsenic-containing solid waste, which requires further treatment, with high treatment costs and a long process flow.

[0003] Black copper mud is an arsenic-containing solid waste produced in the electrolyte purification process during copper electrolytic refining. It has a large output, high toxicity, and complex composition, causing great harm to the environment. The efficient treatment of black copper mud is a difficult problem in copper metallurgy, which leads to most copper smelting companies storing or selling black copper mud at a low price. At present, the methods for treating black copper mud are mainly divided into two categories: pyrometallurgy and hydrometallurgy. The pyrometallurgy is mainly used to recover copper. It has high requirements for equipment and is difficult to meet environmental protection requirements. Arsenic accumulates in the smelting process, which seriously affects the direct recovery rate of copper and product quality, reduces the production capacity of equipment, and is easy to cause harm to human health. The hydrometallurgy has the advantages of being fast, efficient, adaptable, and environmentally friendly, but it will produce arsenic-containing wastewater, which is difficult to treat and has high costs. Summary of the invention

[0004] In view of the deficiencies of the above-mentioned prior art, the present invention provides a method for synergistically recovering valuable elements from high-arsenic alkaline wastewater and black copper mud. The high-arsenic alkaline wastewater and black copper mud are jointly treated to recover valuable elements such as copper and arsenic, thereby treating waste with waste.

[0005] The specific technical solutions are as follows:

[0006] The method for recovering valuable elements by synergistically using high-arsenic alkaline wastewater and black copper mud comprises the following steps:

[0007] S1. Adding black copper mud to high arsenic alkaline wastewater, after the reaction, solid-liquid separation to obtain arsenic-rich liquid and copper slag;

[0008] S2. Sulfuric acid is added to the arsenic-rich solution obtained in step S1, and after the reaction, arsenic trioxide slag and low-arsenic wastewater are obtained;

[0009] S3. The low-arsenic wastewater obtained in step S2 is evaporated and concentrated to obtain sodium sulfate and evaporation mother liquor.

[0010] The high-arsenic alkaline wastewater may come from: wastewater obtained by alkali leaching and oxygen pressure method of arsenic-antimony fly ash.

[0011] The black copper mud may come from: solid waste generated during the electrolyte purification process in the copper electrolytic refining process.

[0012] Specifically, the high-arsenic alkaline wastewater preferably has: an As concentration of 20-45 g / L, and a NaOH concentration of 30-60 g / L.

[0013] Specifically, the black copper mud preferably has an As content of 20wt% to 40wt% and a Cu content of 30wt% to 60wt%.

[0014] The main component of the copper slag obtained in step S1 is cuprous oxide, and the main valuable elements in the copper slag (dry basis) account for: Cu content ≥ 60wt%.

[0015] Wherein, in step S2, the purity of the arsenic trioxide product obtained by washing and drying the arsenic trioxide slag is ≥95%.

[0016] The reaction mechanism of the invention is as follows: the chemical properties of high-arsenic alkaline wastewater and black copper mud are fully utilized, sodium arsenate reacts with copper arsenide in an alkaline solution to generate sodium arsenite and cuprous oxide, cuprous oxide is returned to copper by pyrometallurgy to recover copper, sodium arsenite reacts with sulfuric acid at room temperature to generate arsenous acid and sodium sulfate, arsenous acid precipitates arsenic trioxide at low temperature, and finally main valuable elements copper and arsenic in the high-arsenic alkaline wastewater and black copper mud are fully recovered.

[0017] In step S1, the main reaction is that sodium arsenate in high-arsenic alkaline wastewater reacts with copper arsenide in black copper mud to generate sodium arsenite and cuprous oxide. The main chemical reaction equation is as follows:

[0018] 2Cu 2 As+5NaAsO 3 +2NaOH=2Cu 2 O+7NaAsO 2 +H 2 O;

[0019] 2Cu 3 As+6NaAsO 3 +2NaOH=3Cu 2 O+8NaAsO 2 +H 2 O;

[0020] 2Cu 5 As 2 +11NaAsO 3 +4NaOH=5Cu 2 O+15NaAsO 2 +2H 2 O.

[0021] In step S2, the main reaction is: at room temperature, sodium arsenite reacts with sulfuric acid to generate arsenous acid and sodium sulfate, and sodium hydroxide reacts with sulfuric acid to generate sodium sulfate and water; under low temperature conditions, arsenous acid precipitates arsenic trioxide. The main chemical reaction equation is as follows:

[0022] At room temperature: 2NaAsO 2 +H 2 SO 4 =Na 2 SO 4 +2HAsO 2 ;

[0023] 2NaOH+H 2 SO 4 =Na 2 SO 4 +2H 2 O;

[0024] At low temperature: 2HAsO 2 =As 2 O 3 ↓+H 2 O.

[0025] Furthermore, in step S1, the reaction conditions are preferably: reaction temperature 80-100° C., reaction time 3.0-6.0 h.

[0026] Further, in step S1: the molar ratio of the total amount of arsenic in the high-arsenic alkaline wastewater to the total amount of copper in the black copper mud is preferably 1:(0.2~0.8).

[0027] Furthermore, in step S2, the reaction conditions are preferably: adding sulfuric acid, adjusting the pH to 4.0-6.0, and then reacting for 1.0-2.0 h.

[0028] Furthermore, in step S1: solid-liquid separation is preferably performed by filter press.

[0029] Further, in step S2: after the reaction, arsenic trioxide slag and low-arsenic wastewater are obtained by cooling and crystallization. The cooling and crystallization conditions are preferably: cooling temperature 0-10°C, cooling time 2.0-4.0 h.

[0030] Furthermore, the evaporated mother liquor obtained in step S3 is returned to step S2 for cooling and crystallization.

[0031] Further, in step S2: the arsenic trioxide slag is washed and dried to obtain an arsenic trioxide product and washing wastewater. Based on this, in step S3: the washing wastewater obtained by washing the arsenic trioxide slag is evaporated and concentrated together with the low-arsenic wastewater.

[0032] Further, in step S3: preferably, sodium hydroxide is added to the low-arsenic wastewater for neutralization and then evaporated and concentrated. Specifically, sodium hydroxide solution is added to the low-arsenic wastewater.

[0033] Further, in step S3: the evaporation is preferably multiple-effect evaporation.

[0034] Furthermore, the copper slag obtained in step S1 can be returned to the copper smelting system to recover the copper element.

[0035] The beneficial effects of the present invention are as follows:

[0036] The present invention combines the chemical properties of high-arsenic alkaline wastewater and black copper mud, jointly treats the two, and recovers valuable elements such as arsenic and copper. On the one hand, it provides a coordinated treatment method for high-arsenic alkaline wastewater and black copper mud, reducing the production cost of separately treating high-arsenic alkaline wastewater and black copper mud; on the other hand, it achieves the purpose of "treating waste with waste and turning waste into treasure", avoiding heavy metal pollution problems in the reuse process, and has the advantages of short process flow, high metal recovery rate, low treatment cost, etc., which is of far-reaching significance for improving the economic benefits of enterprises and taking the path of green and sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0038] The principles and features of the present invention are described below in conjunction with examples, which are only used to explain the present invention and are not used to limit the scope of the present invention. The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial sources.

[0039] In a specific implementation manner: high-arsenic alkaline wastewater comes from wastewater obtained by alkali leaching and oxygen pressure method of arsenic-antimony fly ash; black copper mud comes from solid waste generated in the electrolyte purification process during copper electrolytic refining. Example 1

[0040] High arsenic alkaline wastewater and black copper mud synergistically recover valuable elements, including:

[0041] In high-arsenic alkaline wastewater: As concentration is 21.02 g / L, NaOH concentration is 45.21 g / L;

[0042] In the black copper mud: As content is 22.42wt%, Cu content is 57.89wt%, Pb content is 4.87wt%, Au content is 2.02 g / t, and Ag content is 35.41 g / t.

[0043] The steps are as follows:

[0044] S1. Place high-arsenic alkaline wastewater in a reaction tank, slowly add black copper mud into it, and the molar ratio of the total amount of arsenic in the high-arsenic alkaline wastewater to the total amount of copper in the black copper mud is 1:0.2; react at 80 ° C for 4.0 h, filter by pressure to obtain arsenic-rich liquid and copper slag; return the copper slag to the copper smelting system to recover copper;

[0045] S2. At room temperature, the arsenic-rich liquid obtained in step S1 is placed in a reaction tank, and then dilute sulfuric acid with a concentration of 20wt% is added to the reaction tank to adjust its pH value to 4.0, and after stirring for 1.0 h, it is cooled at 0°C for 2.0 h, and after crystallization, solid-liquid separation is performed to obtain arsenic trioxide slag and low-arsenic wastewater; the arsenic trioxide slag is washed and dried to obtain arsenic trioxide product and washing wastewater;

[0046] S3. The low-arsenic wastewater and washing wastewater obtained in step S2 are added with sodium hydroxide solution for neutralization and then concentrated by multi-effect evaporation to obtain sodium sulfate and evaporation mother liquor through crystallization; the evaporation mother liquor is returned to step S2 for cooling and crystallization. Example 2

[0047] High arsenic alkaline wastewater and black copper mud synergistically recover valuable elements, including:

[0048] In high-arsenic alkaline wastewater: As concentration is 44.31 g / L, NaOH concentration is 34.52 g / L;

[0049] In the black copper mud: As content is 37.92wt%, Cu content is 34.61wt%, Pb content is 2.92wt%, Au content is 3.02 g / t, and Ag content is 14.47 g / t.

[0050] The steps are as follows:

[0051] S1. placing high-arsenic alkaline wastewater in a reaction tank, slowly adding black copper mud thereto, wherein the molar ratio of the total amount of arsenic in the high-arsenic alkaline wastewater to the total amount of copper in the black copper mud is 1:0.8; reacting at 100°C for 3.0 h, filtering by pressure, obtaining arsenic-rich liquid and copper slag; and returning the copper slag to the copper smelting system to recover copper;

[0052] S2. At room temperature, the arsenic-rich liquid obtained in step S1 is placed in a reaction tank, and then dilute sulfuric acid with a concentration of 20wt% is added to the reaction tank to adjust its pH value to 6.0, and after stirring for 2.0 hours, it is cooled at 8°C for 4.0 hours, and after crystallization, solid-liquid separation is performed to obtain arsenic trioxide slag and low-arsenic wastewater; the arsenic trioxide slag is washed and dried to obtain arsenic trioxide product and washing wastewater;

[0053] S3. The low-arsenic wastewater and washing wastewater obtained in step S2 are added with sodium hydroxide solution for neutralization and then concentrated by multi-effect evaporation to obtain sodium sulfate and evaporation mother liquor through crystallization; the evaporation mother liquor is returned to step S2 for cooling and crystallization. Example 3

[0054] High arsenic alkaline wastewater and black copper mud synergistically recover valuable elements, including:

[0055] In high arsenic alkaline wastewater: As concentration is 35.35 g / L, NaOH concentration is 55.02 g / L;

[0056] In the black copper mud: As content is 30.24wt%, Cu content is 48.41wt%, Pb content is 2.43wt%, Au content is 5.24 g / t, and Ag content is 7.35 g / t.

[0057] The steps are as follows:

[0058] S1. Place high-arsenic alkaline wastewater in a reaction tank, slowly add black copper mud thereto, the molar ratio of the total amount of arsenic in the high-arsenic alkaline wastewater to the total amount of copper in the black copper mud is 1:0.5; react at 90°C for 6.0 h, filter press to obtain arsenic-rich liquid and copper slag; return the copper slag to the copper smelting system to recover copper;

[0059] S2. At room temperature, the arsenic-rich liquid obtained in step S1 is placed in a reaction tank, and then dilute sulfuric acid with a concentration of 20wt% is added to the reaction tank, and the pH value is adjusted to 5.0. After stirring for 2.0 hours, the mixture is cooled at 5°C for 3.0 hours, and after crystallization, solid-liquid separation is performed to obtain arsenic trioxide slag and low-arsenic wastewater; the arsenic trioxide slag is washed and dried to obtain arsenic trioxide product and washing wastewater;

[0060] S3. The low-arsenic wastewater and washing wastewater obtained in step S2 are added with sodium hydroxide solution for neutralization and then concentrated by multi-effect evaporation to obtain sodium sulfate and evaporation mother liquor through crystallization; the evaporation mother liquor is returned to step S2 for cooling and crystallization.

[0061] test

[0062] The Cu content in the copper slag obtained in step S1 of Examples 1 to 3 and the purity of arsenic trioxide obtained in step S2 were detected, and the results are shown in Table 1. The comprehensive recovery rates of Cu and As elements are shown in Table 2. The Cu content in the copper slag was detected according to the iodine titration method of industrial cuprous oxide (HG / T2961-2010), and the purity of arsenic trioxide was detected according to the method in Appendix A of arsenic trioxide (GB 26721-2011).

[0063] Table 1 Cu content in copper slag and purity of arsenic trioxide

[0064] Example 1 Example 2 Example 3 Cu content (wt%) 65.24 64.37 67.19 Arsenic trioxide purity (%) 96.25 95.98 96.14

[0065] It can be seen from Table 1 that the Cu content in the copper slag obtained by the method of the present invention is above 60wt%, and the purity of arsenic trioxide is above 95%.

[0066] Table 2 Comprehensive recovery rate of each valuable element

[0067] Recovery rate Example 1 Example 2 Example 3 Cu (%) 98.89 98.67 98.57 As(%) 95.32 95.41 95.82

[0068] It can be seen from Table 2 that the comprehensive copper recovery rate obtained by the method of the present invention is above 98%, and the arsenic recovery rate is above 95%.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for recovering valuable elements by synergistically using high-arsenic alkaline wastewater and black copper mud, characterized in that: The steps include: S1. Adding black copper mud to high-arsenic alkaline wastewater, after reaction, solid-liquid separation to obtain arsenic-rich liquid and copper slag; the reaction conditions are: reaction temperature 80~100 ℃, reaction time 3.0~6.0 h; the molar ratio of the total amount of arsenic in the high-arsenic alkaline wastewater to the total amount of copper in the black copper mud is 1:(0.2~0.8); S2. Sulfuric acid is added to the arsenic-rich solution obtained in step S1, and after the reaction, arsenic trioxide slag and low-arsenic wastewater are obtained; S3. The low-arsenic wastewater obtained in step S2 is evaporated and concentrated to obtain sodium sulfate and evaporation mother liquor.

2. The method according to claim 1, characterized in that In step S2, the reaction conditions are: adding sulfuric acid, adjusting the pH to 4.0-6.0, and then reacting for 1.0-2.0 h.

3. The method according to claim 1, characterized in that In step S2: after the reaction, arsenic trioxide slag and low-arsenic wastewater are obtained through cooling and crystallization.

4. The method according to claim 3, characterized in that The evaporated mother liquor obtained in step S3 is returned to step S2 for cooling and crystallization.

5. The method according to any one of claims 1 to 4, characterized in that: In step S2: the arsenic trioxide slag is washed and dried to obtain an arsenic trioxide product and washing wastewater.

6. The method according to claim 5, characterized in that In step S3: the washing wastewater obtained in step S2 and the low-arsenic wastewater are evaporated and concentrated together.

7. The method according to any one of claims 1 to 4, characterized in that: The copper slag obtained in step S1 is returned to the copper smelting system to recover the copper element.

8. The method according to any one of claims 1 to 4, characterized in that: The high-arsenic alkaline wastewater has an As concentration of 20-45 g / L and a NaOH concentration of 30-60 g / L; The black copper mud has an As content of 20wt% to 40wt% and a Cu content of 30wt% to 60wt%.

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