Method for extracting tellurium from copper tailings

Abstract

The invention discloses a method for extracting tellurium from copper tailings, and belongs to the technical field of metallurgical chemical industry. The method comprises the following steps: dissolving the copper tailings in an alkaline solution, adding sodium peroxide, then carrying out pressure leaching under oxygen pressure, and filtering and separating to obtain a leaching solution and leaching residues; and adding a reducing agent into the leachate for reduction, and filtering and separating to obtain tellurium-enriched slag and filtrate. According to the particularity of the copper tailings, sodium peroxide is used for pressurized alkaline leaching, tellurium leaching can be promoted, and then high recovery of tellurium is achieved in cooperation with a directional reduction process. The method for extracting tellurium from copper tailings has the advantages of being short in technological process, high in recovery rate, high in economic value and the like, and waste of secondary resources can be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy and chemical industry, and particularly relates to a method for extracting tellurium from copper tailings. Background Art

[0002] In the copper smelting process, copper tailings, as a by-product of smelting, are rich in a variety of rare metals. Tellurium, as an indispensable material for modern industry and high-tech industries, is widely used in electronics, photovoltaics and other fields. With the rise of renewable energy, the demand for tellurium continues to grow. However, traditional extraction methods often have problems such as low efficiency and high cost. Therefore, in-depth research on innovative technologies for extracting tellurium from copper tailings will help achieve efficient recycling and utilization of resources and promote the development of green metallurgy. Summary of the invention

[0003] In view of the above-mentioned shortcomings of the prior art, the present invention provides a method for extracting tellurium from copper tailings.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] A method for extracting tellurium from copper tailings comprises the following steps:

[0006] (1) dissolving the copper tailings in an alkaline solution, adding sodium peroxide, and then performing pressure leaching under oxygen pressure, filtering and separating to obtain a leachate and a leach residue;

[0007] (2) Add a reducing agent to the leaching solution for reduction, and filter and separate to obtain tellurium-enriched slag and filtrate.

[0008] The copper tailings are powdered waste slag produced in the copper ore dressing process, which contains a variety of elements such as copper, zinc, lead, iron, aluminum, potassium, calcium, selenium, tellurium, etc., among which copper oxide occupies a large proportion.

[0009] As a preferred embodiment of the present invention, the concentration of the alkaline solution is 150-200 g / L, and the liquid-to-solid ratio of the copper tailings dissolved in the alkaline solution is (2-5) mL:1 g.

[0010] As a preferred embodiment of the present invention, the alkali is one or more of sodium hydroxide, calcium hydroxide and magnesium hydroxide.

[0011] As a preferred embodiment of the present invention, the mass ratio of the sodium peroxide to the copper tailings is 0.1-10:1-100.

[0012] As a preferred embodiment of the present invention, the oxygen pressure is 0.3-0.8 kPa, the pressure leaching temperature is 150-200° C., and the time is 2-5 h.

[0013] As a preferred embodiment of the present invention, the reducing agent is sodium sulfite, ascorbic acid or sodium borohydride.

[0014] As a preferred embodiment of the present invention, the reducing agent is added to the leaching solution at a concentration of 1-10 g / L.

[0015] As a preferred embodiment of the present invention, the reduction temperature is 50-80°C and the time is 0.5-2h.

[0016] Compared with the prior art, the invention has the following beneficial effects: according to the particularity of copper tailings, the invention uses sodium peroxide for pressurized alkaline leaching to promote tellurium leaching, and then cooperates with a directional reduction process to achieve high recovery of tellurium. The method for extracting tellurium from copper tailings of the invention has the advantages of short process flow, high recovery rate, high economic value, etc., and can reduce the waste of secondary resources. DETAILED DESCRIPTION

[0017] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0018] Example 1

[0019] A method for extracting tellurium from copper tailings comprises the following steps:

[0020] Weigh 100g of copper tailings, dissolve in 200mL of 150g / L NaOH solution, then add 5g of sodium peroxide, and leaching under pressure at 0.3kPa oxygen pressure and 180°C for 3h, filter and separate to obtain tellurium leaching solution. Add 1g / L of sodium sulfite to the tellurium leaching solution, reduce at 50°C for 1h, filter and obtain tellurium slag with a mass content of more than 65%, and the recovery rate of tellurium is 93.4%.

[0021] Example 2

[0022] A method for extracting tellurium from copper tailings comprises the following steps:

[0023] Weigh 100g of copper tailings, dissolve in 300mL of 180g / L NaOH solution, then add 10g of sodium peroxide, leaching under pressure of 0.7kPa and temperature of 200℃ for 4h, filter and separate to obtain tellurium leaching solution. Add 8g / L of sodium sulfite to the tellurium leaching solution, reduce at 80℃ for 1h, filter and obtain tellurium slag with a content of more than 70%, and the recovery rate of tellurium is 95%.

[0024] Example 3

[0025] A method for extracting tellurium from copper tailings comprises the following steps:

[0026] Weigh 200g of copper tailings, dissolve in 500mL of 170g / L Ca(OH)2 solution, then add 2.5g of sodium peroxide, leaching under pressure of 0.8kPa and temperature of 150°C for 2h, filter and separate to obtain tellurium leaching solution. Add 6g / L ascorbic acid to the tellurium leaching solution, reduce at 60°C for 2h, filter and obtain tellurium slag with a content of more than 74%, and the recovery rate of tellurium is 96.4%.

[0027] Example 4

[0028] A method for extracting tellurium from copper tailings comprises the following steps:

[0029] Weigh 200g of copper tailings, dissolve in 1000mL 200g / L Mg(OH)2 solution, then add 8g of sodium peroxide, leaching under pressure of 0.5kPa and temperature of 170°C for 5h, filter and separate to obtain tellurium leaching solution. Add 10g / L sodium borohydride to the tellurium leaching solution, reduce at 65°C for 0.5h, filter and obtain tellurium slag with a content of more than 78%, and the recovery rate of tellurium is 95.4%.

[0030] Comparative Example 1

[0031] A method for extracting tellurium from copper tailings comprises the following steps:

[0032] Weigh 100g of copper tailings, dissolve in 200mL of 150g / L NaOH solution, leaching under pressure at 0.3kPa oxygen pressure and 180°C for 3h, filter and separate to obtain tellurium leaching solution. Add 1g / L sodium sulfite to the tellurium leaching solution, reduce at 50°C for 1h, filter and obtain tellurium slag with a content of more than 56.7%, and the tellurium recovery rate is 85.3%.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for extracting tellurium from copper tailings, characterized in that: The steps include: (1) dissolving the copper tailings in an alkaline solution, adding sodium peroxide, and then performing pressure leaching under oxygen pressure, filtering and separating to obtain a leachate and a leach residue; (2) Add a reducing agent to the leaching solution for reduction, and filter and separate to obtain tellurium-enriched slag and filtrate.

2. The method for extracting tellurium from copper tailings according to claim 1, characterized in that: The concentration of the alkaline solution is 150-200 g / L, and the liquid-to-solid ratio of the copper tailings dissolved in the alkaline solution is (2-5) mL:1 g.

3. The method for extracting tellurium from copper tailings according to claim 1, characterized in that: The alkali is one or more of sodium hydroxide, calcium hydroxide and magnesium hydroxide.

4. The method for extracting tellurium from copper tailings according to claim 1, characterized in that: The mass ratio of the sodium peroxide to the copper tailings is 0.1-10:1-100.

5. The method for extracting tellurium from copper tailings according to claim 1, characterized in that: The oxygen pressure is 0.3-0.8 kPa, the pressure leaching temperature is 150-200° C., and the time is 2-5 hours.

6. The method for extracting tellurium from copper tailings according to claim 1, characterized in that: The reducing agent is sodium sulfite, ascorbic acid or sodium borohydride.

7. The method for extracting tellurium from copper tailings according to claim 1, characterized in that: The reducing agent is added to the leaching solution at a concentration of 1-10 g / L.

8. The method for extracting tellurium from copper tailings according to claim 1, characterized in that: The reduction temperature is 50-80°C and the time is 0.5-2h.