A method for preparing sponge copper from copper smelting waste slag

Abstract

The invention relates to the technical field of copper smelting waste slag recovery and treatment, and specifically to a method for preparing sponge copper from copper smelting waste slag. The copper smelting waste slag is crushed and then ground to obtain copper smelting waste slag powder, the copper smelting waste slag powder is added into water and mixed to obtain slurry, a liquid culture medium, thiobacillus ferrooxidans bacterial liquid, alicyclobacillus bacterial liquid, acetylacetone and pentaerythritol are added into the slurry for leaching to obtain a leachate, the leachate is filtered, the filtrate is subjected to qualitative and quantitative element analysis, iron powder is added according to the analysis result, the obtained mixed liquid is subjected to hydrothermal reaction to displace copper, the obtained product is filtered again, washed with water, and then vacuum dried to obtain the sponge copper. The sponge copper prepared by the method of the invention has good morphology, high purity and high recovery rate.

Description

Technical Field

[0001] The invention relates to the technical field of copper smelting waste slag recovery and treatment, in particular to a method for preparing sponge copper from copper smelting waste slag. Background Art

[0002] With the continuous development of the copper smelting industry, copper ore resources have become increasingly exhausted. At present, copper ore containing 0.2%-0.3% copper has been mined and utilized, while the copper content of the slag produced in the copper smelting process after depletion is above 0.5%. Copper smelting waste slag is an important secondary resource of copper. Therefore, it is very important to recycle copper smelting waste slag and improve the recovery rate of copper to promote the sustainable development of the copper smelting industry. Summary of the invention

[0003] Purpose of the invention: In view of the above technical problems, the present invention proposes a method for preparing sponge copper from copper smelting waste slag.

[0004] The technical solutions adopted are as follows:

[0005] A method for preparing sponge copper from copper smelting waste slag, as follows:

[0006] S1: crushing and grinding the copper smelting waste slag to obtain copper smelting waste slag powder, and adding the copper smelting waste slag powder into water and mixing to obtain slurry;

[0007] S2: adding liquid culture medium, Thiobacillus ferrooxidans bacterial solution, Alicyclobacillus subtilis bacterial solution, acetylacetone and pentaerythritol to the slurry for leaching to obtain a leaching solution;

[0008] S3: filtering the leaching solution, performing qualitative and quantitative element analysis on the filtrate, adding iron powder according to the analysis results, and subjecting the obtained mixed solution to hydrothermal reaction to displace copper, filtering the obtained product again, washing it with water, and then vacuum drying it to obtain sponge copper.

[0009] Furthermore, the particle size of the copper smelting waste slag powder in S1 is ≤100 μm.

[0010] Furthermore, the weight ratio of the copper smelting waste slag powder to water in S1 is 1:100-500.

[0011] Furthermore, the concentration of the Thiobacillus ferrooxidans bacterial solution is 10 6 -10 8 cfu / mL;

[0012] The concentration of the alicyclobacillus solution is 10 7 -10 9 cfu / mL.

[0013] Furthermore, the composition and content of the liquid culture medium are as follows:

[0014] FeSO4·7H2O 30-50g / L, (NH4)2SO4 1-5g / L, MgSO4·7H2O 0.5-1g / L, CaCl2·2H2O1-3g / L, K2HPO4 0.5-1g / L, MgSO4·7H2O 0.5-1g / L, KCl 0.1-0.5g / L, elemental sulfur 5-10g, yeast extract 1-3g / L, glucose 3-5g / L.

[0015] Furthermore, the Thiobacillus ferrooxidans and the Alicyclobacillus sp. are both domesticated with copper smelting waste slag powder.

[0016] Furthermore, the volume ratio of the slurry, the liquid culture medium, the bacterial solution of Thiobacillus ferrooxidans and the bacterial solution of Bacillus alicyclobacillus is 8-12:5-10:1:1.

[0017] Furthermore, the amount of acetylacetone is 0.1%-0.5% of the mass of the copper smelting waste slag powder;

[0018] The amount of pentaerythritol used is 1%-10% of the mass of the copper smelting waste slag powder.

[0019] Furthermore, the leaching temperature is 25-30°C, the leaching time is 2-4 days, and the pH of the leaching solution needs to be controlled to be maintained at 1.5-2 during leaching.

[0020] Furthermore, microcurrent treatment is also carried out during leaching, with a current density of 0.5-1 mA / cm 2 .

[0021] Beneficial effects of the present invention:

[0022] The invention provides a method for preparing sponge copper from copper smelting waste slag. At present, there are reports on the leaching of copper ions in copper-containing tailings and electronic printed circuit boards by Thiobacillus ferrooxidans, but it is rare to use alicyclic bacillus and Thiobacillus ferrooxidans to leach copper ions from copper smelting waste slag. The composite bacterial community leaching system composed of alicyclic bacillus and Thiobacillus ferrooxidans has high sulfur oxidation activity, provides sufficient protons for the copper ion leaching process, improves the copper leaching rate, and thus improves the yield of sponge copper. The addition of acetylacetone and pentaerythritol can accelerate the erosion and dissolution of copper smelting waste slag, improves the copper leaching rate, and microcurrent treatment promotes the metabolic substrate Fe 2+ The generation of bacteria is effectively promoted, which is beneficial to the biological leaching of copper. The sponge copper prepared by the method of the present invention has good morphology, high purity and high recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a photo of the sponge copper prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0024] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially. The techniques not mentioned in the present invention are all referenced to the prior art. Unless otherwise specified, the following examples and comparative examples are parallel experiments, using the same processing steps and parameters.

[0025] Embodiment 1:

[0026] A method for preparing sponge copper from copper smelting waste slag:

[0027] S1: 5 kg of copper smelting waste slag with a copper content of 0.52% is crushed and ground to obtain copper smelting waste slag powder with a particle size of 50-100 μm, and the copper smelting waste slag powder is added to 1000 L of water and mixed to obtain a slurry;

[0028] S2: Add 600L of liquid culture medium and 100L of Thiobacillus ferrooxidans bacterial solution (concentration of 10 6 cfu / mL), 100L of Alicyclobacillus solution (concentration of 10 8 cfu / mL), 12.5g acetylacetone and 250g pentaerythritol were leached, the leaching temperature was controlled at 25-30°C, the pH of the leaching solution was controlled to be maintained at 1.5-2 during leaching, and microcurrent treatment was performed at a current density of 0.5mA / cm 2 , after leaching for 4 days, the leachate was obtained;

[0029] Among them, the composition and content of the liquid culture medium are as follows:

[0030] FeSO4·7H2O 40g / L, (NH4)2SO4 3g / L, MgSO4·7H2O 0.5g / L, CaCl2·2H2O 2g / L, K2HPO4 0.5g / L, MgSO4·7H2O 0.5g / L, KCl 0.5g / L, elemental sulfur 8g, yeast extract 2g / L, glucose 5g / L;

[0031] The preparation method of Thiobacillus ferrooxidans bacterial solution is as follows:

[0032] The pH of 9K medium was adjusted to 2 with sulfuric acid, and the activated Acidithiobacillus ferrooxidans was cultured at 30°C and 150 rpm until OD 600 When the value of is 0.5-1.0, the culture is stopped and the seed solution is obtained.

[0033] 9K medium contains the following components:

[0034] (NH4)2SO4 3g / L, KC1 0.1g / L, K2HPO4 0.5g / L, MgSO4·H2O 0.5g / L, Ca(NO3)20.01g / L, FeSO4·H2O 44.2g / L;

[0035] The seed solution was centrifuged at 5000 rpm for 5 min, the supernatant was discarded, the precipitate was resuspended in 9K medium, and then added to 9K medium containing 1% copper smelting waste powder by mass ratio but no ferrous sulfate. The volume ratio of the resuspended solution to the 9K medium was 5:5. The culture was carried out at 25°C and 150 rpm. When the culture solution OD 600 After reaching 0.5-1.0, the strain is transferred to the next 9K culture medium with a concentration gradient of copper smelting waste slag powder at a ratio of 1:10, and domesticated in the order of increasing concentration of copper smelting waste slag powder. After inoculation for 5 times (1%, 3%, 5%, 7% and 10%), the strain is adapted to the copper smelting waste slag powder, and at least 30 generations are passed in the culture system containing 10% copper smelting waste slag powder to complete the domestication of the strain and obtain the domesticated ferrothiobacillus ferrooxidans bacterial solution.

[0036] The preparation method of alicyclobacillus bacterial solution is as follows:

[0037] The pH of the BAM medium was adjusted to 1.5 with sulfuric acid, and the activated Alicyclobacillus was expanded and cultured at 25°C and 150 rpm until the OD 600 When the value of is 0.5-1.0, the culture is stopped and the seed solution is obtained.

[0038] BAM medium contained the following components: (NH4)2SO4 0.5 g / L, K2HPO4 2 g / L, MgSO4·H2O 0.3 g / L, CaCl2·2H2O 0.5 g / L, FeSO4·H2O 50 g / L;

[0039] The seed solution was centrifuged at 5000 rpm for 5 min, the supernatant was discarded, the precipitate was resuspended in BAM medium, and then added to BAM medium containing 1% copper smelting waste powder by mass ratio but no ferrous sulfate. The volume ratio of the resuspended solution to the BAM medium was 5:5. The culture was carried out at 25°C and 150 rpm. When the culture solution OD 600 After reaching 0.5-1.0, the strain was transferred to the next BAM culture medium with a copper smelting waste slag powder concentration gradient at a ratio of 1:10, and domesticated in the order of increasing copper smelting waste slag powder concentration. After inoculation for 5 times (1%, 3%, 5%, 7% and 10%), the strain was adapted to the copper smelting waste slag powder, and at least 30 generations were passed in the culture system containing 10% copper smelting waste slag powder to complete the domestication of the strain and obtain the domesticated Alicyclobacillus subtilis liquid.

[0040] S3: The leachate is filtered, and the filtrate is subjected to qualitative and quantitative element analysis. According to the analysis results, iron powder having the same amount of copper element is added, and the resulting mixed solution is added to a hydrothermal reactor, which is sealed and heated to 120°C for hydrothermal reaction for 18 hours to displace the copper. The product is filtered again, washed with water, and vacuum dried at 80°C for 10 hours to obtain 22.5 g of sponge copper with a yield of 86.5% and a purity of 96.5%.

[0041] Embodiment 2:

[0042] The same as Example 1, except that the current density is 0.8 mA / cm 2 The yield of sponge copper obtained is 87.3% and the purity is 96.1%.

[0043] Embodiment 3:

[0044] The same as Example 1, except that the current density is 1 mA / cm 2 The yield of sponge copper obtained is 83.9% and the purity is 97.0%.

[0045] Comparative Example 1:

[0046] The method is basically the same as Example 1, except that the bacterial solution of Thiobacillus ferrooxidans is used instead of the bacterial solution of Bacillus alicyclicus. The yield of the obtained sponge copper is 74.4% and the purity is 97.3%.

[0047] Comparative Example 2:

[0048] The method is basically the same as Example 1, except that the bacterial solution of Alicyclobacillus subtilis is used instead of the bacterial solution of Thiobacillus ferrooxidans. The yield of the obtained sponge copper is 68.2% and the purity is 94.8%.

[0049] Comparative Example 3:

[0050] The method is basically the same as Example 1, except that no microcurrent treatment is performed during leaching. The yield of the obtained sponge copper is 80.5% and the purity is 95.6%.

[0051] Comparative Example 4:

[0052] The method is basically the same as Example 1, except that acetylacetone is not added, and the yield of the obtained sponge copper is 78.4% and the purity is 90.2%.

[0053] Comparative Example 5:

[0054] The method is basically the same as Example 1, except that pentaerythritol is not added, and the yield of the obtained sponge copper is 75.1% and the purity is 92.5%.

[0055] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing sponge copper from copper smelting waste slag, characterized in that: The details are as follows: S1: crushing and grinding copper smelting waste slag with a copper content of 0.52% to obtain copper smelting waste slag powder, and adding the copper smelting waste slag powder into water and mixing to obtain slurry; S2: adding liquid culture medium, Thiobacillus ferrooxidans bacterial solution, Alicyclobacillus subtilis bacterial solution, acetylacetone and pentaerythritol to the slurry for leaching to obtain a leaching solution; S3: filtering the leachate, performing qualitative and quantitative element analysis on the filtrate, adding iron powder according to the analysis results, and subjecting the obtained mixed solution to hydrothermal reaction to displace copper, filtering the obtained product again, washing with water, and vacuum drying to obtain sponge copper; The particle size of the copper smelting waste slag powder in S1 is ≤100 μm; The weight ratio of copper smelting waste slag powder to water in S1 is 1:100-500; The concentration of the Thiobacillus ferrooxidans bacterial solution is 10 6 -10 8 cfu / mL; The concentration of the alicyclobacillus solution is 10 7 -10 9 cfu / mL; The composition and content of the liquid culture medium are as follows: FeSO4·7H2O 30-50g / L, (NH4)2SO4 1-5g / L, MgSO4·7H2O 0.5-1g / L, CaCl2·2H2O 1-3g / L, K2HPO4 0.5-1g / L, MgSO4·7H2O 0.5-1g / L, KCl 0.1-0.5g / L, elemental sulfur 5-10g, yeast extract 1-3g / L, glucose 3-5g / L; The Thiobacillus ferrooxidans and the Alicyclobacillus sp. are both domesticated with copper smelting waste slag powder; The volume ratio of the slurry, liquid culture medium, Thiobacillus ferrooxidans bacterial solution and Alicyclobacillus bacterial solution is 8-12:5-10:1:1; The amount of acetylacetone used is 0.1%-0.5% of the mass of the copper smelting waste slag powder; The amount of pentaerythritol used is 1%-10% of the mass of the copper smelting waste slag powder; The leaching temperature is 25-30℃, the leaching time is 2-4 days, and the pH of the leaching solution needs to be controlled to be maintained at 1.5-2 during leaching; Microcurrent treatment is also carried out during leaching, with a current density of 0.5-1mA / cm 2 .

Images