Leaching Method of Copper and Cobalt in Low-Sulfur and High-Copper Copper-Cobalt Sulfide Concentrate

Abstract

The present invention provides a method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate, comprising: preparing a first pulp by using water to treat high-copper copper-cobalt sulfide concentrate according to a liquid-solid ratio of (1-4):1 to obtain a first pulp; performing a first acid leaching on the first pulp for 1 h to 4 h according to an acid-ore ratio of 150 kg / t to 450 kg / t to obtain a first leachate and a first leaching residue; performing a roasting treatment on the first leaching residue at a temperature of 650 °C to 800 °C to obtain a roasted residue; preparing a second pulp by using water to treat the roasted residue according to a liquid-solid ratio of (6-10):1 to obtain a second pulp; and performing a second acid leaching on the second pulp according to an acid-ore ratio of 650 kg / t to 1800 kg / t to obtain a second leachate. The present invention effectively improves the leaching rates of cobalt and copper elements in high-copper copper-cobalt sulfide concentrate through two-stage acid leaching and reduces the leaching amount of iron elements.

Description

Technical Field

[0001] The present invention relates to the field of hydrometallurgy, and in particular, to a method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate. Background Art

[0002] The Democratic Republic of the Congo is the world's largest copper-cobalt resource mining area, with characteristics such as large reserves of raw ore and high grades. The local copper-cobalt resources are basically divided into two types: copper-cobalt oxide ore and copper-cobalt sulfide ore. The oxidation rate of copper-cobalt oxide ore is extremely high, generally buried relatively shallow, and the burial depth is generally between 0 and 120 m. Copper-cobalt sulfide ore is mostly located in deep ore bodies, requiring underground mining, and the reserves are huge. With the continuous mining of copper-cobalt minerals, the high-grade and easily treatable copper-cobalt oxide ore resources are decreasing day by day, and the refractory copper-cobalt sulfide ore has become a research hotspot. At present, the main smelting processes for copper sulfide concentrate include pyrometallurgical smelting, sulfuric acid roasting - hydrometallurgy, oxidation roasting - hydrometallurgy, pressure acid leaching, etc. Due to the characteristics of low sulfur and high copper in the copper sulfide concentrate in this area, pyrometallurgical smelting requires the addition of ore species containing Fe and S. There is a lack of chalcopyrite or pyrite required for ore blending locally, and the advantages of pyrometallurgical smelting cannot be exerted. At the same time, pyrometallurgical smelting will produce a large amount of sulfur dioxide, with high environmental protection investment and environmental pollution problems, and there are also problems such as low recovery rate of valuable metals; pressure acid leaching is carried out under high temperature and high pressure, with high requirements for operators and equipment. The oxidation roasting - acid leaching process is one of the main technologies for treating copper sulfide concentrate and is more attractive to the Democratic Republic of the Congo.

[0003] Patent CN 110846496 B is a method for sulfuric acid roasting and smelting of sulfur-containing copper-cobalt concentrate. It adopts the methods of roasting and smelting and atmospheric pressure leaching. After ore blending, it is slurried with sodium salt wastewater, fed wet, sulfuric acidated fluidized bed roasting and then leached at atmospheric pressure. The sulfuric acidation rates of cobalt and copper are both > 93%, and the leaching rates of cobalt and copper are both > 96%. Patent CN 114950712 A provides a combined treatment process for comprehensive recovery of copper and cobalt. After roasting the copper sulfide concentrate, it enters the hydrometallurgical leaching process, and the copper oxide concentrate is directly leached by hydrometallurgy. The above two patents mainly introduce the application of the atmospheric pressure leaching process after roasting in copper-cobalt concentrate. However, in the treatment process of both, the iron in the sulfur-containing copper-cobalt concentrate is not removed, so the content of impurity iron is relatively high after the leaching is finally completed. At the same time, the treatment methods provided by the above two patents are complex and costly, and it is difficult to apply them on a large scale.

[0004] Based on this, for copper-cobalt sulfide concentrate with the characteristics of low sulfur and high copper, how to provide a leaching method with a simple process and low cost, and achieve the leaching of cobalt and copper therein with a high leaching rate, while maintaining a low leaching rate of iron, is one of the important technical problems to be solved in this field. Summary of the Invention

[0005] The main object of the present invention is to provide a method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate, so as to solve the problem in the prior art that for copper-cobalt sulfide concentrate with the characteristics of low sulfur and high copper, it is impossible to extract cobalt and copper therein with low cost and high leaching rate while maintaining a low leaching rate of iron.

[0006] To achieve the above object, the present invention provides a method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate, including: Step S1, according to a liquid-solid ratio of (1~4):1, preparing a first pulp with water for high-copper copper-cobalt sulfide concentrate to obtain a first pulp; Step S2, according to an acid-ore ratio of 150 kg / t~450 kg / t, performing a first acid leaching on the first pulp for 1 h~4 h to obtain a first leachate and a first leaching residue; Step S3, performing a roasting treatment on the first leaching residue at a temperature of 650 °C~800 °C to obtain a roasted residue; Step S4, according to a liquid-solid ratio of (6~10):1, preparing a second pulp with water for the roasted residue to obtain a second pulp; Step S5, according to an acid-ore ratio of 650 kg / t~1800 kg / t, performing a second acid leaching on the second pulp to obtain a second leachate.

[0007] Further, by weight, the high-copper copper-cobalt sulfide concentrate includes 40~55 parts of Cu, 0.2~1.0 part of Co, 1.0~8.0 parts of Fe, and 7.0~12.0 parts of S.

[0008] Further, in Step S2, the first acid leaching is microwave acid leaching, and the microwave power used in the microwave acid leaching is 200 W~2000 W.

[0009] Further, in Step S2, the microwave acid leaching is carried out under the conditions of a temperature of 30 °C~50 °C and a stirring speed of 300 r / min~700 r / min.

[0010] Even further, the acid-ore ratio in Step S2 is 200 kg / t~400 kg / t.

[0011] Further, in the first leaching residue, the content of sulfur element is 13 wt%~18 wt%.

[0012] Further, in Step S3, the roasting treatment method is fluidized roasting, and the air linear velocity used in the fluidized roasting is 0.2 m / s~0.8 m / s, and the air-ore ratio is 0.5 m 3 / kg~8.0 m 3 / kg.

[0013] Even further, in Step S3, the fluidized roasting time is 1 h~3 h.

[0014] Further, the acid-to-ore ratio in step S5 is 700 kg / t to 1500 kg / t, and the time for the second acid leaching is 2 h to 4 h.

[0015] Further, in the second leachate, the iron content is 0.05 g / L to 0.11 g / L.

[0016] Applying the technical solution of the present invention, the leaching rates of cobalt and copper elements in high-copper copper-cobalt sulfide concentrate are effectively improved through two-stage acid leaching, and the leaching amount of iron element is reduced. Through the intermediate roasting process, sulfur in the high-copper copper-cobalt sulfide concentrate is pre-enriched, which is beneficial to realizing the self-heating reaction in the roasting process, increasing the sulfur dioxide concentration in the flue gas, providing guarantee for the self-heating roasting in the subsequent roasting process, and creating favorable conditions for the subsequent acid leaching at the same time, making the subsequent metal extraction process more efficient. Specific Embodiments

[0017] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0018] As described in the background art, in the prior art, for copper-cobalt sulfide concentrate with the characteristics of low sulfur and high copper, there are problems that it is impossible to extract cobalt and copper therein with low cost and high leaching rate while maintaining a low leaching rate of iron. To solve the above technical problems, the present invention provides a method for leaching copper and cobalt in high-copper copper-cobalt sulfide concentrate, including: step S1, preparing a first pulp with water for high-copper copper-cobalt sulfide concentrate according to a liquid-solid ratio of (1 to 4):1 to obtain a first pulp; step S2, performing a first acid leaching on the first pulp for 1 h to 4 h according to an acid-to-ore ratio of 150 kg / t to 450 kg / t to obtain a first leachate and a first leach residue; step S3, performing a roasting treatment on the first leach residue at a temperature of 650 °C to 800 °C to obtain a roasted residue; step S4, preparing a second pulp with water for the roasted residue according to a liquid-solid ratio of (6 to 10):1 to obtain a second pulp; step S5, performing a second acid leaching on the second pulp according to an acid-to-ore ratio of 650 kg / t to 1800 kg / t to obtain a second leachate.

[0019] The above leaching method provided by the present invention adopts a combined process of pre-leaching - roasting and atmospheric leaching for special high-copper and low-sulfur copper-cobalt sulfide concentrate. First, the first acid leaching is carried out to preliminarily leach copper and cobalt in the copper-cobalt sulfide concentrate and enrich sulfur in the copper-cobalt sulfide concentrate, which is beneficial to realizing the self-heating reaction in the roasting furnace, increasing the sulfur dioxide concentration in the flue gas, and providing guarantee for the self-heating roasting in the subsequent roasting process. Then, through the roasting process, a large amount of sulfides in the pre-leached residue are removed and converted into cobalt and copper oxides that are easily soluble in sulfuric acid solution. Finally, through the second acid leaching, a leachate with extremely low iron content is obtained.

[0020] In the above process, first, the high-copper copper-cobalt sulfide concentrate is mixed with water at a liquid-solid ratio of (1-4):1 to prepare the first pulp, ensuring that the pulp has sufficient fluidity to provide a good reaction medium for subsequent acid leaching. Then, through the acidic environment in the first acid leaching, the structure of the copper-cobalt sulfide concentrate is destroyed, enabling copper and cobalt to be preliminarily dissolved into the solution, thereby increasing the preliminary leaching rate of the metals. At the same time, sulfur is released from the minerals and enriched in the first leaching residue, creating conditions for the self-heating reaction in subsequent roasting. Optimizing the acid-to-ore ratio and leaching time in the first acid leaching is to control the leaching degree of iron and prevent excessive iron from entering the subsequent processes. Then, the first leaching residue is roasted at a temperature of 650°C - 800°C. The high-temperature roasting within this temperature range promotes the full combustion of sulfur in the first leaching residue, which is converted into sulfur dioxide gas and released. Meanwhile, copper-cobalt oxides are formed, facilitating dissolution in subsequent acid leaching. More importantly, the sulfur enriched in the pre-leaching residue burns to provide part of the heat, contributing to the realization of the self-heating reaction, reducing the use of external heat sources, and thus significantly reducing energy consumption. After that, the roasted residue is mixed with water at a ratio of (6-10):1 to ensure sufficient contact area between the roasted residue and the acid solution, promoting the dissolution of metals, while controlling the concentration of the solution to ensure leaching efficiency. Finally, the conditions of the acid leaching are precisely controlled again to achieve the second acid leaching and produce the second leaching solution. At this time, the oxides converted by roasting are quickly dissolved in the sulfuric acid solution, achieving the efficient leaching of copper and cobalt. Since the leaching of iron has been controlled in the first acid leaching process, and roasting further reduces the possibility of iron dissolution, the iron content in the second leaching solution can be controlled at an extremely low level, reducing various impacts caused by it as an impurity.

[0021] In summary, the above combined leaching method provided by the present invention not only improves the recovery rates of copper and cobalt and optimizes the metal purity, but also realizes simple operation, cost savings, and improvement of environmental protection effects through the combination of the first acid leaching, roasting, and the second acid leaching. It provides an efficient and economical solution for the treatment of high-copper copper-cobalt sulfide concentrate and can be applied on a large scale with lower environmental and condition requirements.

[0022] In several typical embodiments, by weight, the high-copper copper-cobalt sulfide concentrate contains 40-55 parts of Cu, 0.2-1.0 part of Co, 1.0-8.0 parts of Fe, and 7.0-12.0 parts of S. In order to more effectively adapt to the above leaching method and the corresponding parameter conditions, thereby enhancing the efficiency and selectivity of the above leaching process, and ultimately increasing the recovery rates of copper and cobalt, the composition of the high-copper copper-cobalt sulfide concentrate is further precisely optimized as follows: by weight, the high-copper copper-cobalt sulfide concentrate contains 50-55 parts of Cu, 0.2-0.5 part of Co, 3.0-6.0 parts of Fe, and 8.0-11.0 parts of S.

[0023] In several more typical embodiments, for the processing raw material, namely high-copper copper-cobalt sulfide concentrate, preferably calculated based on its weight being 100%, the proportion of high-copper copper-cobalt sulfide concentrate with a particle size less than 0.038 mm is 70% - 90%. This particle size range means that there are more active sites in the high-copper copper-cobalt sulfide concentrate to be processed that can participate in chemical reactions, thereby increasing the leaching rate of cobalt and copper therein. At the same time, the ore raw materials within this particle size range are more easily penetrated, thus accelerating the rate of metal dissolution from the ore. At the same time, during the boiling roasting process after the first leaching, the leaching residue formed by the concentrate with this particle size characteristic can contact the air more evenly, promoting the rapid oxidation of sulfides therein. In short, the inventor has preferably selected the high-copper copper-cobalt sulfide concentrate with the above particle size characteristics through a large number of experiments, which can not only increase the leaching rate of cobalt and copper metals and product quality, but also optimize the process conditions, bringing more significant environmental benefits.

[0024] One of the characteristics of the copper-cobalt sulfide concentrate with high copper and low sulfur processed by the present invention is that the sulfur content is relatively low, and the leaching of sulfides is a key step in releasing copper and cobalt metals. Under such conditions, it is preferred that the first acid leaching in step S2 is microwave acid leaching, and the microwave power used in the microwave acid leaching is 200W - 2000W. This is because microwave acid leaching uses microwave energy to directly act on polar molecules in the ore, inducing the molecules to vibrate rapidly, generating a thermal effect and accelerating the reaction. And this direct heating method can penetrate more effectively into the interior of ore particles compared with the external heating of ordinary acid leaching, and can promote the rapid decomposition of sulfides even at a lower sulfur content, increasing the leaching rate of copper and cobalt. At the same time, for the ore system processed by the present invention, ordinary acid leaching may be inefficient due to the difficult leaching property of copper sulfide, while in microwave acid leaching, the catalytic effect of microwaves can reduce the reaction activation energy, promoting the chemical reaction between copper-cobalt sulfides and acid, and achieving a higher leaching recovery rate of cobalt and copper even at a lower leaching temperature.

[0025] In particular, based on the high-copper copper-cobalt sulfide concentrate with special particle size characteristics preferably selected by the present invention, it is further preferred that the microwave power used in the microwave pre-leaching is 500W - 1000W, which can more effectively prompt the rapid absorption of microwave energy, thereby accelerating the decomposition of copper and cobalt minerals and the enrichment of sulfur elements, and ultimately achieving a higher leaching rate of cobalt and copper elements with lower energy consumption.

[0026] To enable better leaching effect in microwave acid leaching, further enhance the dissolution rates of cobalt and copper in this process, and accelerate the enrichment of sulfur, preferably in step S2, the microwave acid leaching is carried out under the conditions of a temperature of 30°C to 50°C and a stirring speed of 300 r / min to 700 r / min. Further preferably in step S2, the acid-to-ore ratio used in microwave acid leaching is 200 kg / t to 400 kg / t, so as to more effectively dissolve copper and cobalt in the ore, and at the same time control the acid consumption to adapt to the special conditions of microwave acid leaching, reducing problems such as excessive dissolution of iron, environmental pollution or cost increase caused by over-acid leaching.

[0027] In several typical embodiments, after the first acid leaching is completed and the first leaching residue is obtained, the sulfur element content in the obtained first leaching residue is 13 wt% to 18 wt%. That is to say, through the optimization of the first acid leaching method and the optimization of various condition parameters involved in the optimized microwave acid leaching process, the enrichment of sulfur in the original copper-cobalt sulfide concentrate can be particularly effectively achieved, so that it can burn fully and provide heat during the subsequent roasting process, promote the realization of self-heating reaction, reduce the use of external heat sources, and thus more significantly reduce the energy consumption of the overall leaching method.

[0028] For the first leaching residue with a high sulfur content obtained by the first acid leaching, preferably in step S3, the roasting treatment method is fluidized bed roasting, and the air linear velocity used in the fluidized bed roasting is 0.2 m / s to 0.8 m / s, and the air-to-ore ratio is 0.5 m 3 / kg to 8.0 m 3 / kg. Compared with the conventional roasting method without using a fluidized bed roasting furnace, the fluidized bed roasting carried out according to the above parameter settings can, through the generation of strong gas-solid turbulence, make the leaching residue particles fully contact with air, accelerate the oxidation reaction of sulfides therein and form SO2 gas, achieve more complete desulfurization in a shorter time, and improve the desulfurization efficiency. During the fluidized bed roasting process, the heat released by the oxidation reaction of sulfides can maintain or even accelerate the roasting process, thus reducing the consumption of external heat sources and ultimately significantly reducing the energy consumption. In addition, the leaching residue particles can be more evenly surrounded by hot air in the fluidized bed, which is beneficial to the rapid oxidation of sulfides, and at the same time reduces the excessive sintering of metal oxides caused by local overheating, thus affecting their dissolution performance in the subsequent second acid leaching process. In order to more effectively realize the above process, more effectively reduce the energy consumption and increase the total leaching rate of cobalt and copper, further preferably the air linear velocity used in the fluidized bed roasting is 0.3 m / s to 6 m / s, and the air-to-ore ratio is 1.0 m 3 / kg to 5.0 m 3 / kg.

[0029] Moreover, it is worth mentioning that the processed raw materials within the above-mentioned preferred particle size range of the present invention have a particularly suitable size range for the leaching residues obtained after the first acid leaching. They are more easily dispersed in the fluidized bed, thus forming a more uniform temperature field, and can more efficiently remove sulfides during the roasting process, generating oxides that are easy to leach with acid subsequently, and ultimately further improving the leaching rates of cobalt and copper.

[0030] In addition, in order to achieve a more ideal desulfurization effect, improve the recovery rates of cobalt and copper in the subsequent second leaching step, reduce energy consumption and the degree of oxidation of metals, and reduce their losses, it is preferred that in step S3, the fluidized roasting time is 1 h to 3 h. Under the above conditions, the total desulfurization rate during the fluidized roasting process is 75% to 85%, that is, the removal and efficient utilization of sulfur in the low-sulfur and high-copper copper-cobalt sulfide concentrate are effectively realized.

[0031] Furthermore, it is preferred that the acid-to-ore ratio in step S5 is 700 kg / t to 1500 kg / t, and the time for the second acid leaching is 2 h to 4 h, so as to more effectively dissolve the residual copper and cobalt in the roasted slag within this acid-to-ore ratio range and improve their total leaching rates.

[0032] In several typical embodiments, the iron content in the second leaching solution is 0.05 g / L to 0.11 g / L. That is to say, by leaching and treating the high-copper copper-cobalt sulfide concentrate by the above method provided by the present invention, the dissolution of iron in the ore can be effectively reduced, thereby improving the purity of copper and cobalt, and also effectively reducing various influences caused by iron elements as impurities. In particular, if the iron content in the finally obtained leaching solution is relatively high, on the one hand, it will be mixed into the copper and cobalt products during the subsequent purification and recovery processes, affecting the quality of the subsequent products and reducing their purity. On the other hand, the subsequent treatment of the copper-cobalt leaching solution is generally solvent extraction followed by electrodeposition, and iron ions may interfere with the solvent extraction process, reducing the extraction efficiency and affecting the recovery rates of copper and cobalt; at the same time, during the electrodeposition process, the presence of iron ions may cause uneven deposition on the electrode surface, affecting the electrodeposition efficiency and the quality of the subsequent products.

[0033] The following further describes the present application in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present application.

[0034] Unless otherwise defined, all professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention.

[0035] Example 1

[0036] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate:

[0037] Provided is a high-copper copper-cobalt sulfide concentrate, the composition content of which is shown in Table 1, and impurity components such as SiO2 are not shown. In addition, among the high-copper copper-cobalt sulfide concentrates to be processed, the proportion of high-copper copper-cobalt sulfide concentrates with a particle size less than 0.038 mm is 80%.

[0038] Table 1

[0039]

[0040] (1) Take 100 g of the above-mentioned high-copper copper-cobalt sulfide concentrate and water, and prepare a pulp according to a liquid-solid ratio of 2:1 to obtain a first pulp.

[0041] (2) According to an acid-to-ore ratio of 400 kg / t, and under the conditions of a temperature of 35 °C and a stirring speed of 500 r / min, perform a first acid leaching, i.e., microwave acid leaching, on the first pulp. The microwave power of the microwave acid leaching is 1000 W, and microwave pre-leaching is carried out for 2 h under this operating condition. Then, solid-liquid separation is performed on the first pulp after the pre-leaching to obtain a first leachate and a first leach residue. During this process, the pre-leaching residue rate (i.e., the residue rate) is approximately 70.12%, the copper leaching rate is 31.56%, the cobalt leaching rate is 38.97%, the iron leaching rate is 48.23%; and in the obtained first leach residue, the sulfur content is 15.69 wt%.

[0042] (3) Transfer the obtained first leach residue to a fluidized bed furnace (i.e., a boiling furnace) and perform oxidative boiling roasting at 750 °C for 2 h. The air linear velocity used for the boiling roasting is 0.45 m / s, and the air-to-ore ratio is 3.2 m 3 / kg. During this process, the total desulfurization rate is 77.23% (the calculation of the total desulfurization rate follows: (sulfur content before roasting - sulfur content after roasting) / sulfur content before roasting × 100%).

[0043] (4) Take the obtained roasted residue and water, and prepare a pulp according to a liquid-solid ratio of 8:1 to obtain a second pulp.

[0044] (5) According to an acid-to-ore ratio of 800 kg / t, perform a second acid leaching, i.e., atmospheric pressure leaching, on the obtained second pulp, and the leaching time is 120 min to obtain a second leachate, in which the iron content is 0.069 g / L.

[0045] Example 2

[0046] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate:

[0047] (1) Take 100 g of the above-mentioned high-copper copper-cobalt sulfide concentrate and water, and prepare a pulp according to a liquid-solid ratio of 2:1 to obtain a first pulp.

[0048] (2) The first pulp is subjected to the first acid leaching, i.e., microwave acid leaching, according to an acid-to-ore ratio of 200 kg / t, at a temperature of 35 °C and a stirring speed of 500 r / min. The microwave power for the microwave acid leaching is 1000 W, and the pulp is pre-leached by microwave for 2 h under these operating conditions. Then, solid-liquid separation is carried out on the pre-leached first pulp to obtain a first leachate and a first leached residue. During this process, the pre-leached residue rate is approximately 74.26%, the copper leaching rate is 26.92%, the cobalt leaching rate is 30.26%, and the iron leaching rate is 42.79%; and in the obtained first leached residue, the sulfur content is 15.24 wt%.

[0049] (3) - (5) The processing conditions are the same as those in Example 1.

[0050] Example 3

[0051] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0052] (1) Take 100 g of the above-mentioned high-copper copper-cobalt sulfide concentrate and water, and prepare a pulp according to a liquid-to-solid ratio of 2:1 to obtain a first pulp.

[0053] (2) The first pulp is subjected to the first acid leaching, i.e., microwave acid leaching, according to an acid-to-ore ratio of 200 kg / t, at a temperature of 35 °C and a stirring speed of 500 r / min. The microwave power for the microwave acid leaching is 500 W, and the pulp is pre-leached by microwave for 2 h under these operating conditions. Then, solid-liquid separation is carried out on the pre-leached first pulp to obtain a first leachate and a first leached residue. During this process, the pre-leached residue rate is approximately 60.14%, the copper leaching rate is 28.31%, the cobalt leaching rate is 32.42%, and the iron leaching rate is 42.53%; and in the obtained first leached residue, the sulfur content is 13.97 wt%.

[0054] (3) - (5) The processing conditions are the same as those in Example 1.

[0055] Example 4

[0056] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0057] The difference between this example and Example 1 is only that: the liquid-to-solid ratio in the pulp preparation process in step (1) is changed to 4:1.

[0058] Under these conditions, the pre-leached residue rate obtained in step (2) is approximately 70.12%, the copper leaching rate is 30.12%, the cobalt leaching rate is 31.24%, and the iron leaching rate is 39.27%; and in the obtained first leached residue, the sulfur content is 14.38 wt%.

[0059] Example 5

[0060] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0061] The difference between this example and Example 1 is only that: the time of microwave acid leaching in step (2) is changed to 4 h.

[0062] Under these conditions, the pre-leaching residue rate obtained in step (2) is about 70.12%, the copper leaching rate is 32.34%, the cobalt leaching rate is 34.28%, and the iron leaching rate is 47.56%; and in the obtained first leaching residue, the sulfur content is 16.27 wt%.

[0063] Example 6

[0064] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0065] The difference between this example and Example 1 is only that: the temperature of microwave acid leaching in step (2) is changed to 50 °C, and the stirring speed is changed to 300 r / min.

[0066] Under these conditions, the pre-leaching residue rate obtained in step (2) is about 72.31%, the copper leaching rate is 30.24%, the cobalt leaching rate is 38.62%, and the iron leaching rate is 47.23%; and in the obtained first leaching residue, the sulfur content is 15.43 wt%.

[0067] Example 7

[0068] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0069] The difference between this example and Example 1 is only that: the air linear velocity of fluidized roasting in step (3) is changed to 0.6 m / s, and the air-to-ore ratio is changed to 5 m 3 / kg.

[0070] Example 8

[0071] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0072] The difference between this example and Example 1 is only that: the temperature of fluidized roasting in step (3) is changed to 800 °C, and the time is changed to 3 h.

[0073] Example 9

[0074] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0075] The difference between this example and Example 1 is only that: the liquid-to-solid ratio in the pulp preparation process in step (4) is changed to 10:1.

[0076] Example 10

[0077] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0078] The difference between this embodiment and Embodiment 1 is only that: the acid-to-ore ratio of the second acid leaching in step (5) is changed to 1500 kg / t.

[0079] Embodiment 11

[0080] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0081] The difference between this embodiment and Embodiment 1 is only that: the leaching time of the second acid leaching in step (5) is changed to 4 h.

[0082] Embodiment 12

[0083] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0084] The difference between this embodiment and Embodiment 1 is only that: the particle size of the high-copper copper-cobalt sulfide concentrate to be processed is changed so that the proportion of the high-copper copper-cobalt sulfide concentrate with a particle size less than 0.038 mm is 50%.

[0085] Embodiment 13

[0086] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0087] The difference between this embodiment and Embodiment 1 is only that: the microwave power of the microwave acid leaching in step (2) is changed to 200 W.

[0088] Under these conditions, the pre-leaching residue rate obtained in step (2) is about 75.28%, the copper leaching rate is 28.01%, the cobalt leaching rate is 31.23%, the iron leaching rate is 40.24%; and in the obtained first leaching residue, the sulfur content is 17.92 wt%.

[0089] Embodiment 14

[0090] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0091] The difference between this embodiment and Embodiment 1 is only that: the microwave power of the microwave acid leaching in step (2) is changed to 2000 W.

[0092] Under these conditions, the pre-leaching residue rate obtained in step (2) is about 59.23%, the copper leaching rate is 28.51%, the cobalt leaching rate is 32.07%, the iron leaching rate is 45.23%; and in the obtained first leaching residue, the sulfur content is 12.89 wt%.

[0093] Embodiment 15

[0094] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0095] The difference between this embodiment and Embodiment 1 is only that: the microwave power of the microwave acid leaching in step (2) is changed to 0 W, that is, the first acid leaching is carried out under the condition of no microwave.

[0096] Embodiment 16

[0097] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0098] The difference between this embodiment and Embodiment 1 is only that: the acid-to-ore ratio of the microwave acid leaching in step (2) is changed to 150 kg / t.

[0099] Under this condition, the pre-leaching residue rate obtained in step (2) is about 74.34%, the copper leaching rate is 27.72%, the cobalt leaching rate is 30.24%, the iron leaching rate is 40.27%; and in the obtained first leaching residue, the sulfur content is 18.23 wt%.

[0100] Embodiment 17

[0101] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0102] The difference between this embodiment and Embodiment 1 is only that: the acid-to-ore ratio of the microwave acid leaching in step (2) is changed to 450 kg / t.

[0103] Under this condition, the pre-leaching residue rate obtained in step (2) is about 69.95%, the copper leaching rate is 28.46%, the cobalt leaching rate is 31.29%, the iron leaching rate is 42.86%; and in the obtained first leaching residue, the sulfur content is 14.23 wt%.

[0104] Embodiment 18

[0105] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0106] The difference between this embodiment and Embodiment 1 is only that: the air linear velocity of the fluidized bed roasting in step (3) is changed to 0.2 m / s, and the air-to-ore ratio is changed to 0.5 m 3 / kg.

[0107] Embodiment 19

[0108] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0109] The difference between this embodiment and Embodiment 1 is only that: the air linear velocity of the fluidized bed roasting in step (3) is changed to 0.8 m / s, and the air-to-ore ratio is changed to 8.0 m 3 / kg.

[0110] Embodiment 20

[0111] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0112] The difference between this embodiment and Embodiment 1 is only that: the acid-to-ore ratio of the second acid leaching in step (5) is changed to 1800 kg / t.

[0113] During the second acid leaching process of this embodiment, the amount of acid used increases significantly, which will significantly improve the leaching rate of each element. However, the content of impurity iron in the leaching solution will also increase significantly.

[0114] Comparative Example 1

[0115] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0116] The difference between this comparative example and Embodiment 1 is only that: the acid-to-ore ratio of the microwave acid leaching in step (2) is changed to 100 kg / t.

[0117] Under these conditions, the pre-leaching residue rate obtained in step (2) is about 87.34%, the copper leaching rate is 12.57%, the cobalt leaching rate is 18.65%, the iron leaching rate is 23.57%; and in the obtained first leaching residue, the sulfur content is 14.56 wt%.

[0118] Comparative Example 2

[0119] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0120] The difference between this comparative example and Embodiment 1 is only that: the liquid-to-solid ratio in the pulp preparation process of step (1) is changed to 6:1.

[0121] Under these conditions, the pre-leaching residue rate obtained in step (2) is about 82.15%, the copper leaching rate is 26.57%, the cobalt leaching rate is 29.36%, the iron leaching rate is 32.12%; and in the obtained first leaching residue, the sulfur content is 13.38 wt%.

[0122] Comparative Example 3

[0123] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0124] The difference between this comparative example and Embodiment 1 is only that: the time of microwave acid leaching in step (2) is changed to 40 min.

[0125] Under these conditions, the pre-leaching residue rate obtained in step (2) is about 82.56%, the copper leaching rate is 25.52%, the cobalt leaching rate is 28.32%, the iron leaching rate is 31.13%; and in the obtained first leaching residue, the sulfur content is 11.37 wt%.

[0126] Comparative Example 4

[0127] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0128] The difference between this comparative example and Example 1 is only that: in step (3), the temperature of boiling roasting is changed to 600 °C and the time is changed to 1 h.

[0129] Comparative Example 5

[0130] A method for leaching copper and cobalt from high-copper copper-cobalt sulfide concentrate:

[0131] The difference between this comparative example and Example 1 lies only in steps (4) and (5), which are specifically as follows.

[0132] (4) Take the obtained roasted slag and water, and prepare a pulp according to a liquid-solid ratio of 5:1 to obtain a second pulp.

[0133] (5) Carry out a second acid leaching, i.e., atmospheric pressure leaching, on the obtained second pulp according to an acid-to-ore ratio of 600 kg / t, and the leaching time is 90 min to obtain a second leaching solution.

[0134] The total leaching rates of Co element and Cu element in the leaching methods provided by each example and comparative example are shown in Table 2; the total desulfurization rate during the roasting process is also shown in Table 2; the content of Fe element in the finally obtained leaching solution is also shown in Table 2.

[0135] Table 2

[0136]

[0137] From the above description, it can be seen that the above embodiments of the present invention achieve the extraction of cobalt element and copper element from high-copper copper-cobalt sulfide concentrate with a higher leaching rate with lower energy consumption, while ensuring that the content of iron in the finally obtained leaching solution is lower, the subsequent treatment is simpler, and the application value is higher.

[0138] Specifically, for special high-copper and low-sulfur copper-cobalt sulfide concentrate, a combined process of pre-leaching - roasting - atmospheric pressure leaching is adopted. First, the preparation of ore oxygen is carried out, and by controlling the particle size of the ore particles, the leaching rates of copper and cobalt in the subsequent process are improved. Through pre-leaching, by controlling conditions such as acid-to-ore ratio, microwave power, and microwave temperature, copper and cobalt are preliminarily dissolved into the solution, enriching sulfur in the copper-cobalt sulfide concentrate while improving the preliminary leaching rate of metals, which is beneficial to realizing the self-heating reaction of the roasting furnace, increasing the sulfur dioxide concentration in the flue gas, and providing guarantee for the self-heating roasting in the subsequent roasting process. And through boiling roasting, a large amount of sulfides in the pre-leaching slag are removed and transformed into cobalt-copper oxides that are easily soluble in sulfuric acid solution.

[0139] Among them, especially in Examples 14 and 17, the microwave power and acid-to-ore ratio in the microwave acid leaching process were respectively enhanced, exceeding the preferred range of the present invention. In this case, the leaching rates of copper and cobalt will increase, but the iron content in the final leachate will also increase accordingly, which is more unfavorable for the subsequent product treatment compared with Example 1.

[0140] In Example 19, the air linear velocity of the fluidized roasting in step (3) was changed to 0.8 m / s, and the air-to-ore ratio was changed to 8.0 m 3 / kg. Under these conditions, a relatively high leaching rate of copper and cobalt can also be obtained. However, since the increase in process parameters will lead to an increase in the corresponding energy consumption, the overall economic benefit is slightly worse than that of Example 1. That is to say, when optimizing the roasting linear velocity and air-to-ore ratio, although increasing the linear velocity and air-to-ore ratio can enhance the fluidized roasting effect, the benefit of the increased effect is much smaller than the input cost. Therefore, the linear velocity and air-to-ore ratio within the preferred range are selected.

[0141] Finally, through the second acid leaching, the roasting slag and water are in a ratio of (6 - 10):1, so as to ensure that the roasting slag and the acid solution have a sufficient contact area, promote the dissolution of metals, and at the same time control the solution concentration to improve the leaching efficiency.

[0142] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such terms can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those described herein, for example.

[0143] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and changes can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for leaching copper and cobalt from a high-copper sulfide copper-cobalt concentrate, characterized in that: include: Step S1, preparing a first slurry from the high-copper copper-cobalt sulfide concentrate with water according to a liquid-to-solid ratio of (1-4):1 to obtain a first slurry; Taking the weight of the high-copper copper-cobalt sulfide concentrate as 100%, the high-copper copper-cobalt sulfide concentrate having a particle size of less than 0.038 mm accounts for 70% to 90%; Step S2, subjecting the first slurry to a first acid leaching for 1 h to 4 h at an acid-ore ratio of 150 kg / t to 450 kg / t to obtain a first leachate and a first leach residue; The first acid leaching is microwave acid leaching, and the microwave power used in the microwave acid leaching is 500W~1000W; The microwave acid leaching is carried out at a temperature of 30°C to 50°C and a stirring speed of 300r / min to 700r / min; Step S3, calcining the first leached residue at a temperature of 650° C. to 800° C. to obtain calcined residue; Step S4, preparing a second slurry with water on the roasted slag according to a liquid-to-solid ratio of (6-10):1 to obtain a second slurry; Step S5, performing a second acid leaching on the second slurry according to an acid-ore ratio of 650 kg / t to 1800 kg / t to obtain a second leachate.

2. The method for leaching copper and cobalt from high-copper sulfide copper-cobalt concentrate according to claim 1, characterized in that: In parts by weight, the high-copper copper-cobalt sulfide concentrate includes 40-55 parts of Cu, 0.2-1.0 parts of Co, 1.0-8.0 parts of Fe and 7.0-12.0 parts of S.

3. The method for leaching copper and cobalt from a high-copper sulfide copper-cobalt concentrate according to claim 1 or 2, characterized in that: The acid-ore ratio in step S2 is 200kg / t to 400kg / t.

4. The method for leaching copper and cobalt from high-copper sulfide copper-cobalt concentrate according to claim 3, characterized in that: In the first leaching residue, the content of sulfur element is 13wt%~18wt%.

5. The method for leaching copper and cobalt from high-copper sulfide copper-cobalt concentrate according to claim 1 or 2, characterized in that: In step S3, the roasting treatment is performed by fluidized bed roasting, and the air linear velocity used in the fluidized bed roasting is 0.2 m / s to 0.8 m / s, and the air-to-ore ratio is 0.5 m / s. 3 / kg~8.0m 3 / kg.

6. The method for leaching copper and cobalt from high-copper sulfide copper-cobalt concentrate according to claim 5, characterized in that: In step S3, the time of the fluidized bed roasting is 1 h to 3 h.

7. The method for leaching copper and cobalt from high-copper sulfide copper-cobalt concentrate according to claim 1 or 2, characterized in that: The acid-ore ratio in step S5 is 700kg / t to 1500kg / t, and the second acid leaching time is 2h to 4h.

8. The method for leaching copper and cobalt from high-copper sulfide copper-cobalt concentrate according to claim 1 or 2, characterized in that: The iron content in the second leaching solution is 0.05 g / L~0.11 g / L.

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