Treatment method and application of copper-cobalt slag

Abstract

The invention provides a treatment method and application of copper-cobalt slag, and the treatment method comprises the following steps: mixing copper-cobalt slag, acid liquor and first water, and slurrying to obtain slurry; roasting the slurry at high temperature to obtain roasted slag; in percentage by mass, the content of silicon in the slag is 10%-15%, and the content of iron in the slag is 20%-25%; and after roasting slag is sequentially subjected to high-temperature water leaching and solid-liquid separation, a liquid phase is collected, and copper-cobalt leaching liquid is obtained. According to the method, a sulfuric acid solution roasting method and high-temperature water leaching treatment are cooperated, so that the influence of silica gel and iron gel on the filtering performance of the copper-cobalt leaching solution is effectively avoided, and relatively thorough copper-cobalt extraction is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste recycling and treatment, and particularly relates to a method for treating copper-cobalt slag and application thereof. Background Art

[0002] Cobalt is a key strategic metal widely used in the chemical, electromechanical, aerospace, and defense industries. With the rapid development of new energy vehicles and the growing consumption of various electronic products, demand for cobalt for batteries is increasing annually. my country's cobalt production primarily comes from copper-nickel sulfide ores, with a smaller amount coming from other metal smelting byproducts, such as purified cobalt slag from hydrometallurgical zinc smelting. To achieve sustainable resource development, research into extracting copper and cobalt from tailings is of great significance.

[0003] While there has been relatively extensive research in China on copper and cobalt extraction technologies from copper-cobalt ores, there has been relatively little research on the extraction of copper-cobalt slag from Zambian copper-cobalt ores. The Zambian copper-cobalt ore resources are low-grade, with complex occurrences. Furthermore, Zambian copper-cobalt slag is high in silicon and iron, making resource extraction technology relatively immature. Acid leaching is commonly used to treat this type of slag, resulting in low copper and cobalt leaching rates and the production of silica gel and iron gel. This results in extremely poor filtration performance of the acid leachate, hindering its subsequent resource utilization. Summary of the Invention

[0004] The present invention aims to solve the technical problems in the above-mentioned conventional technology of treating high-silicon and high-iron copper-cobalt slag, such as low copper and cobalt leaching rates, generation of silica gel and iron gel, and extremely poor filtration performance of the acid leaching solution. The present invention provides a method for treating copper-cobalt slag, characterized in that it comprises the steps of: mixing the copper-cobalt slag, an acid solution, and a first water to form a slurry; calcining the slurry at a high temperature to obtain a calcined slag; the silicon content of the slag is 10% to 15%, and the iron content is 20% to 25% by mass;

[0005] The roasted slag is sequentially subjected to high-temperature water leaching and solid-liquid separation, and the liquid phase is collected to obtain a copper-cobalt leaching solution.

[0006] Furthermore, the copper-cobalt slag includes Zambian copper-cobalt slag produced in Zambia.

[0007] Furthermore, the acid solution includes a sulfuric acid solution.

[0008] Furthermore, the mass ratio of the copper-cobalt slag to the acid solution is 1:1-2, and the mass ratio of the first water to the acid solution is 1:1-2.

[0009] Furthermore, the temperature of the high-temperature roasting is 110° C. to 120° C., and the duration of the high-temperature roasting is not less than 20 hours.

[0010] Furthermore, the temperature of the high-temperature water immersion is 40° C. to 50° C., and the duration of the high-temperature water immersion is not less than 1 hour.

[0011] Furthermore, the high-temperature water immersion includes the steps of: mixing the crushed roasted slag with a second water, heating it to 40-50° C. and then keeping it warm for more than 1 hour; the mass volume ratio of the roasted slag to the second water is 1g:5-10ml.

[0012] Furthermore, the leaching rate of copper in the copper-cobalt slag is not less than 95%, and the leaching rate of cobalt is not less than 80%.

[0013] Furthermore, in terms of mass fraction, the copper content in the copper-cobalt slag is 0.55% to 0.60%, and the cobalt content in the copper-cobalt slag is 0.75% to 0.80%.

[0014] The present invention provides an application of the copper-cobalt slag treatment method as described above in copper-cobalt slag treatment.

[0015] Compared with the prior art, the present invention has at least the following advantages:

[0016] The present invention provides a method for treating copper-cobalt slag. This method utilizes an acid roasting process (including mixed slurrying and high-temperature roasting) to specifically treat high-silicon and high-iron copper-cobalt slag with a silicon content of 10% to 15% and an iron content of 20% to 25%. This method converts insoluble oxides into readily soluble sulfuric acid salts, effectively avoiding the effects of silica gel and iron gel on the filtration performance of the copper-cobalt leachate. This method achieves a more thorough copper and cobalt extraction, with a slag copper leaching rate exceeding 95% and a cobalt leaching rate exceeding 80%. In comparison, the acid leaching method used in conventional techniques creates an environment suitable for the formation of silica gel and iron gel, resulting in extremely poor leachate filtration performance.

[0017] Specifically, the present invention pre-treats the copper-cobalt slag (i.e., the process of mixing and slurrying the copper-cobalt slag, acid solution, and first water, the same below), and mixes the copper-cobalt slag, acid solution, and first water to form a slurry, so that the copper-cobalt slag and the acid solution are fully mixed, thereby improving the conversion efficiency between substances.

[0018] The present invention combines pretreatment with high-temperature roasting, roasting the slurry in a high-temperature environment of 110°C to 120°C, so that the oxides or other insoluble compounds in the copper-cobalt slag are more thoroughly converted into soluble sulfuric acid solution salts; in addition, high-temperature roasting changes the structure and particle size distribution of the copper-cobalt mineral particles, making the copper-cobalt mineral particles looser and significantly optimizing the permeability.

[0019] Based on the optimization of the chemical composition and physical properties of copper-cobalt slag particles by the acid roasting method, the present invention subsequently undertakes high-temperature water leaching treatment to maximize the impact of the improved chemical composition and physical properties on the leaching effect of valuable metals, greatly increasing the copper-cobalt leaching rate and improving the filtration performance.

[0020] The main reaction formulas involved in the acid solution roasting + water immersion process of the present invention include:

[0021] 2Co203+8H + →4Co 2+ +O2+4H2O

[0022] CoO2+4H + →Co 2+ +2H2O

[0023] Fe2O3+6H + →Fe 3+ +3H2O

[0024] FeO+2H + →Fe 2+ +H2O

[0025] CuO+2H + →Cu 2+ +H2O BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0027] Figure 1 This is the XRD pattern of the Zambian copper-cobalt slag treated in Example 1 of the present invention. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0029] Moreover, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0030] When numerical ranges are given in the examples, it should be understood that unless otherwise specified herein, both endpoints of each numerical range and any value between the two endpoints may be used. Unless otherwise defined, all technical and scientific terms used herein are consistent with the prior art as understood by those skilled in the art and the description of the present invention. Any prior art methods, devices, and materials similar or equivalent to those in the examples of the present invention may also be used to implement the present invention.

[0031] The grade of copper and cobalt ore resources in Zambia is low, the occurrence of copper and cobalt is complex, and the Zambian copper and cobalt slag is high-silicon and high-iron copper and cobalt slag, and the resource extraction technology is relatively immature.

[0032] Specifically: Zambian copper-cobalt slag is high in silicon and iron. Its complex chemical composition and physical structure make traditional resource extraction technologies ineffective. Currently, acid leaching is one of the most commonly used techniques for treating copper-cobalt slag. However, this traditional acid leaching method has a fatal flaw when treating high-silicon, high-iron copper-cobalt slag. During the acid leaching process, the high silicon and iron content react with the acid in a complex series of chemical reactions, producing silica gel and iron colloid. These silica gel and iron colloid have extremely small particle sizes and large specific surface areas, forming a viscous colloidal substance in the slag system. This colloidal substance adheres to the filter medium in large quantities, rapidly clogging the pores and dramatically increasing the filtration resistance. This severely interferes with subsequent filtration operations, slowing the filtration rate and potentially even completely stopping the filtration process.

[0033] In the commonly used technology, as shown in Comparative Example 8, when treating high-silicon and high-iron copper-cobalt slag with a silicon content of 10% to 15% and an iron content of 20% to 25%, acid leaching treatment is often used, including the steps of: mixing the copper-cobalt slag and 98% sulfuric acid solution water in a ratio of 1:1:10, setting the acid leaching temperature to 80 to 90°C, stirring and acid leaching for 6 hours, filtering solid-liquid separation is extremely difficult, and the copper leaching rate is 65% to 70%, and the cobalt leaching rate is 40% to 45%.

[0034] Therefore, developing a treatment technology specifically for high-silicon, high-iron copper-cobalt slag is crucial and urgent. This new technology must effectively circumvent the generation of silica gel and iron gel during traditional acid leaching, thereby preventing their adverse effects on filtration performance. This innovative treatment technology can significantly improve filtration efficiency and reduce production costs while ensuring the quality and purity of the final product, providing solid technical support for the sustainable development of Zambia's copper-cobalt mining industry.

[0035] Based on the above, in order to solve the technical problems in the above conventional technology of treating high-silicon and high-iron copper-cobalt slag, such as low copper and cobalt leaching rates, the generation of silica gel and iron glue, and extremely poor filtration performance of the acid leaching solution, the present invention provides a method for treating copper-cobalt slag, comprising the steps of:

[0036] S1. The copper-cobalt slag, the acid solution, and the first water are mixed and slurried to obtain a slurry; the slurry is calcined at a high temperature to obtain a calcined slag; the silicon content of the slag is 10% to 15% and the iron content is 20% to 25% by mass.

[0037] In some embodiments of the present invention, the copper content in the copper-cobalt slag is 10% to 15%, and the cobalt content in the copper-cobalt slag is 20% to 25%, calculated by mass fraction.

[0038] In some more specific embodiments of the present invention, the copper-cobalt slag includes Zambian copper-cobalt slag produced in Zambia.

[0039] In some embodiments of the present invention, the acid solution comprises a sulfuric acid solution. Exemplarily, the mass concentration of the sulfuric acid solution may be 95% to 98%; further exemplary, the mass concentration of the sulfuric acid solution may be 98%.

[0040] In some embodiments of the present invention, the mass ratio of copper-cobalt slag to the acid solution may be 1:1-2, and the mass ratio of the first water to the acid solution may be 1:1-2; in some more specific embodiments, the mass ratio of copper-cobalt slag to the acid solution may be 1:1, and the mass ratio of the first water to the acid solution may be 1:1.

[0041] In some embodiments of the present invention, the high temperature roasting temperature may be 110° C. to 120° C., and the high temperature roasting time may be no less than 20 hours. In some more specific embodiments, the high temperature roasting time may be 20 to 24 hours.

[0042] The present invention combines pretreatment with high-temperature roasting, and roasts the slurry in a high-temperature environment of 110°C to 120°C. This can, on the basis of pretreatment, more thoroughly convert the oxides or other insoluble compounds in the copper-cobalt slag into readily soluble sulfuric acid solution salts. In addition, high-temperature roasting changes the structure and particle size distribution of the copper-cobalt mineral particles, making them looser and significantly optimizing their permeability.

[0043] Among them, the main reaction formulas involved in the acid solution roasting + water immersion process of the present invention include:

[0044] 2Co203+8H + →4Co 2+ +O2+4H2O

[0045] CoO2+4H + →Co 2+ +2H2O

[0046] Fe2O3+6H + →Fe 3+ +3H2O

[0047] FeO+2H + →Fe 2+ +H2O

[0048] CuO+2H + →Cu 2+ +H2O

[0049] In the present invention, the first water is added during the pretreatment process to fully mix the sulfuric acid solution and the slag into slurry.

[0050] S2. The calcined slag is sequentially subjected to high-temperature water leaching and solid-liquid separation, and the liquid phase is collected to obtain a copper-cobalt leaching solution.

[0051] In some embodiments of the present invention, the high-temperature water immersion temperature may be 40°C to 50°C, and the high-temperature water immersion duration may be no less than 1 hour. It should be noted that the high-temperature water immersion duration is calculated from the time the temperature reaches 40°C to 50°C. In more specific embodiments, the high-temperature water immersion duration may be 1 to 4 hours.

[0052] In some embodiments of the present invention, the high-temperature water immersion may include the steps of: mixing the crushed roasted slag with a second water, heating it to 40-50°C and keeping it warm for more than 1 hour; the mass ratio of the roasted slag to the second water is 1g:5-10ml.

[0053] In some embodiments of the present invention, high-temperature water immersion can be performed under stirring conditions.

[0054] In some embodiments of the present invention, the leaching rate of copper in the copper-cobalt slag is not less than 95%, and the leaching rate of cobalt is not less than 80%. In some specific embodiments of the present invention, the leaching rate of copper in the copper-cobalt slag is not less than 95%, and the leaching rate of cobalt is not less than 80%. In some more specific embodiments of the present invention, the leaching rate of copper in the copper-cobalt slag is not less than 95%, and the leaching rate of cobalt is not less than 85%.

[0055] The present invention also provides an application of the method for treating copper-cobalt slag as described above in treating copper-cobalt slag.

[0056] In order to facilitate those skilled in the art to further understand the present invention, examples are given below:

[0057] Example 1

[0058] Take 20g of Zambian copper-cobalt slag, add 20g of 98% sulfuric acid solution to the copper-cobalt slag; then add 20g of first water to the mixture, mix and slurry to obtain a slurry; wherein the XRD pattern of the Zambian copper-cobalt slag is as follows Figure 1 As shown in the figure, the composition of Zambian copper-cobalt slag, in terms of mass fraction, includes: Cu 0.56%, Co 0.76%, Fe 23.92%, Si 12.78%, Ca 7.49%, Al 2.33%, K 1.65%, and moisture content 8.1%.

[0059] The slurry was placed in a muffle furnace, set at 115°C, and calcined for 20 hours to obtain calcined slag;

[0060] After the calcined slag is crushed, process water (i.e., second water) is added at a mass volume ratio of 1 g:10 ml, i.e., 200 ml of water is added and stirred for immersion in water; the immersion temperature is set to 45°C and the immersion time is 2 h;

[0061] The leaching solution has excellent filtration performance, with a copper leaching rate of 98.2% and a cobalt leaching rate of 84.2%.

[0062] Example 2

[0063] Take 20 g of the Zambian copper-cobalt slag in Example 1, add 20 g of a 98% sulfuric acid solution to the copper-cobalt slag; then add 10 g of the first water, mix and slurry to obtain a slurry;

[0064] The slurry was placed in a muffle furnace, set at 120°C, and calcined for 22 hours to obtain calcined slag;

[0065] After the calcined slag is crushed, process water (i.e., second water) is added at a mass volume ratio of 1 g:10 ml, i.e., 200 ml of water is added and stirred for immersion in water; the immersion temperature is set to 40°C and the immersion time is 1 hour;

[0066] The leaching solution has excellent filtration performance, with a copper leaching rate of 97.4% and a cobalt leaching rate of 81.1%.

[0067] Example 3

[0068] Take 20 g of the Zambian copper-cobalt slag in Example 1, add 20 g of a 98% sulfuric acid solution to the copper-cobalt slag; then add 20 g of the first water to the mixture, mix and slurry to obtain a slurry;

[0069] The slurry was placed in a muffle furnace, set at 115°C, and calcined for 20 hours to obtain calcined slag;

[0070] After the roasted slag is crushed, process water (i.e., the second water) is added at a solid-liquid ratio of 1g:5ml, i.e., 100ml of water is added and stirred for immersion; the immersion temperature is set to 45°C and the immersion time is 1h;

[0071] The leaching solution has excellent filtration performance, with a copper leaching rate of 95.1% and a cobalt leaching rate of 83.0%.

[0072] Comparative Example 1

[0073] In this comparative example, only the amount of the first water added was adjusted compared to Example 1. 20 g of Zambian copper-cobalt slag was prepared, and 20 g of 98% sulfuric acid solution was added to the slag at a mass ratio of 1:1. The first water was not added to form a slurry, and other conditions remained unchanged.

[0074] In this comparative example, the final copper leaching rate was 78.3%, and the cobalt leaching rate was 51.5%.

[0075] Comparative Example 2

[0076] In this comparative example, compared to Example 1, only the mass ratio of 98% sulfuric acid solution to Zambian copper-cobalt slag was adjusted. To 20 g of Zambian copper-cobalt slag, 98% sulfuric acid solution was added at a mass ratio of 1:2 between 98% sulfuric acid solution and copper-cobalt slag, resulting in a total mass of 10 g of sulfuric acid solution. All other conditions remained unchanged.

[0077] In this comparative example, the final copper leaching rate was 89.1%, and the cobalt leaching rate was 72.7%.

[0078] Comparative Example 3

[0079] In this comparative example, only the mass ratio of the Zambian copper slag to the 98% sulfuric acid solution was adjusted compared to Example 1. 20 g of Zambian copper-cobalt slag was added to the 98% sulfuric acid solution at a mass ratio of 3:4, i.e., the mass of the sulfuric acid solution was 15 g. All other conditions remained unchanged.

[0080] In this comparative example, the final copper leaching rate was 94.9%, and the cobalt leaching rate was 81.4%.

[0081] Comparative Example 4

[0082] Compared with Example 2, the slurry calcination temperature in this comparative example was set to 220° C., and other conditions remained unchanged.

[0083] In this comparative example, the final copper leaching rate was 94.1%, and the cobalt leaching rate was 64.3%.

[0084] Comparative Example 5

[0085] Compared with Example 2, the slurry roasting temperature was set to 300° C., and other conditions remained unchanged. In this comparative example, roasting produced a large amount of white smoke, and the sulfuric acid solution decomposed significantly, resulting in a final copper leaching rate of 80.4% and a cobalt leaching rate of 57.6%.

[0086] Comparative Example 6

[0087] Compared with Example 2, the slurry roasting time in this comparative example was set to 15 h, and other conditions remained unchanged.

[0088] In this comparative example, the final copper leaching rate was 90.0%, and the cobalt leaching rate was 72.9%.

[0089] Comparative Example 7

[0090] Compared with Example 2, the slurry roasting time in this comparative example was set to 10 h, and other conditions remained unchanged.

[0091] In this comparative example, the final copper leaching rate was 46.6%, and the cobalt leaching rate was 68.3%.

[0092] Comparative Example 8

[0093] The copper-cobalt slag of Example 1, 98% sulfuric acid solution, and water were mixed in a mass ratio of 1:1:10 for acid leaching. Specifically, 20 g of 98% sulfuric acid solution was added to 20 g of the Zambian copper-cobalt slag, followed by 200 g of water. The acid leaching temperature was set at 80-90°C, and the mixture was stirred for 6 hours. Solid-liquid separation by filtration was extremely difficult, and the copper leaching rate was 65%-70%, and the cobalt leaching rate was 40%-45%.

[0094] The leaching solution prepared in this comparative example has extremely poor filtration performance, produces silica gel and iron glue, and has a copper leaching rate of 65% to 70% and a cobalt leaching rate of 40% to 45%.

[0095] The above technical solutions of the present invention are only preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention's description and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for treating copper-cobalt slag, characterized in that: The method comprises the following steps: mixing copper-cobalt slag, acid solution and first water to obtain slurry; calcining the slurry at high temperature to obtain calcined slag; wherein the silicon content of the slag is 10% to 15% and the iron content is 20% to 25% by mass; The roasted slag is sequentially subjected to high-temperature water leaching and solid-liquid separation, and the liquid phase is collected to obtain a copper-cobalt leaching solution.

2. The method for treating copper-cobalt slag according to claim 1, wherein: The copper-cobalt slag includes Zambian copper-cobalt slag produced in Zambia.

3. The method for treating copper-cobalt slag according to claim 1, wherein: The acid solution includes a sulfuric acid solution.

4. The method for treating copper-cobalt slag according to claim 1, wherein: The mass ratio of the copper-cobalt slag to the acid solution is 1:1-2, and the mass ratio of the first water to the acid solution is 1:1-2.

5. The method for treating copper-cobalt slag according to claim 1, wherein: The temperature of the high-temperature roasting is 110° C. to 120° C., and the duration of the high-temperature roasting is not less than 20 hours.

6. The method for treating copper-cobalt slag according to claim 1, characterized in that: The temperature of the high-temperature water immersion is 40° C. to 50° C., and the duration of the high-temperature water immersion is not less than 1 hour.

7. The method for treating copper-cobalt slag according to claim 6, characterized in that: The high-temperature water immersion comprises the following steps: mixing the crushed roasted slag with second water, heating to 40° C. to 50° C. and then keeping the temperature for more than 1 hour; the mass volume ratio of the roasted slag to the second water is 1 g: 5 to 10 ml.

8. The method for treating copper-cobalt slag according to claim 1, characterized in that: The leaching rate of copper in the copper-cobalt slag is not less than 95%, and the leaching rate of cobalt is not less than 80%.

9. The method for treating copper-cobalt slag according to claim 1, characterized in that: Calculated by mass fraction, the copper content in the copper-cobalt slag is 0.55% to 0.60%, and the cobalt content in the copper-cobalt slag is 0.75% to 0.80%.

10. Use of the method for treating copper-cobalt slag according to any one of claims 1 to 9 in treating copper-cobalt slag.

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