Leaching method for copper and cobalt in low-sulfur high-copper copper sulfide cobalt concentrate

Abstract

The invention provides a method for leaching copper and cobalt in high-copper copper-cobalt sulfide concentrate, which comprises the following steps of: preparing first ore pulp from the high-copper copper-cobalt sulfide concentrate by using water according to a liquid-solid ratio of (1-4): 1 to obtain first ore pulp; according to the acid-ore ratio of 150 kg / t-450 kg / t, the first ore pulp is subjected to first acid leaching for 1 h-4 h, and first leaching liquid and first leaching residues are obtained; roasting treatment is conducted on the first leaching residues at the temperature of 650-800 DEG C, and roasted residues are obtained; according to the liquid-solid ratio of (6-10): 1, the roasting slag is subjected to second ore pulp preparation with water, and second ore pulp is obtained; according to the acid-ore ratio of 650-1800 kg / t, the second ore pulp is subjected to second acid leaching, and second leaching liquid is obtained. According to the method, through two-stage acid leaching, the leaching rate of cobalt and copper elements in the high-copper copper sulfide cobalt concentrate is effectively increased, and the leaching amount of the iron element is reduced.

Description

Technical Field

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

[0002] The Democratic Republic of the Congo is the world's largest copper-cobalt resource mining area, with large reserves of raw ore and high grade. The local copper-cobalt resources are basically divided into two types: copper-cobalt oxide ore and copper-cobalt sulfide ore: copper-cobalt oxide ore has an extremely high oxidation rate and is generally shallowly buried, with a burial depth of 0-120 m; copper-cobalt sulfide ore is mostly located in deep ore bodies, requiring pit mining, and has huge reserves. With the continuous mining of copper-cobalt minerals, high-grade and easy-to-process copper-cobalt oxide ore resources are decreasing, and difficult-to-process copper-cobalt sulfide ore has become a research hotspot. At present, the main smelting processes of copper sulfide concentrate are pyrometallurgy, sulfuric acid roasting-wet process, oxidation roasting-wet process, pressure acid leaching, etc. Since the copper sulfide concentrate in the region has the characteristics of low sulfur and high copper, the use of pyrometallurgy requires the addition of minerals containing Fe and S. The local area lacks the chalcopyrite or pyrite required for the ore blending, and the advantages of pyrometallurgy cannot be brought into play. In addition, pyrometallurgy will produce a large amount of sulfur dioxide, which will require large environmental protection investments, cause environmental pollution, and also cause problems such as low yield of valuable metals. Pressurized acid leaching is carried out under high temperature and high pressure, which has high requirements for operators and equipment. Oxidative roasting-acid leaching process is one of the main technologies for processing copper sulfide concentrate, which is more attractive to Congo (DRC).

[0003] Patent CN 110846496 B is a method for sulphation roasting and smelting of sulfur-containing copper-cobalt concentrate. It adopts the method of roasting and smelting and atmospheric pressure leaching. After ore preparation, sodium salt wastewater is used for slurry preparation, wet feeding, sulphation boiling roasting and atmospheric pressure leaching, the sulphation rate of cobalt and copper is both >93%, and the leaching rate of cobalt and copper is both >96%. Patent CN 114950712 A provides a combined treatment process for comprehensive recovery of copper and cobalt. After roasting, the sulphide copper concentrate enters the wet leaching process, and the oxide copper concentrate is directly leached by wet method. The above two patents mainly focus on the application of atmospheric pressure leaching process after roasting in copper-cobalt concentrate, but in the treatment process of the two, the iron in the sulfur-containing copper-cobalt concentrate is not removed, so the content of impurity iron after leaching is finally completed is high. At the same time, the treatment methods provided by the above two patents are complex and costly, and difficult to be applied on a large scale.

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

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

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

[0007] Furthermore, 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 in parts by weight.

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

[0009] Furthermore, in step S2, microwave acid leaching is carried out at a temperature of 30°C to 50°C and a stirring speed of 300 r / min to 700 r / min.

[0010] Furthermore, the acid-ore ratio in step S2 is 200kg / t~400kg / t.

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

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

[0013] Furthermore, in step S3, the time of boiling roasting is 1h~3h.

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

[0015] Furthermore, in the second leaching solution, the iron content is 0.05 g / L~0.11 g / L.

[0016] By applying the technical solution of the present invention, the leaching rate of cobalt and copper elements in high-copper sulfide copper-cobalt concentrate is effectively improved through two-stage acid leaching, and the leaching amount of iron elements is reduced. Through the intermediate roasting process, the sulfur in the high-copper sulfide copper-cobalt concentrate is pre-enriched, which is conducive to the self-heating reaction during the roasting process, and the sulfur dioxide concentration in the flue gas is increased, which provides a guarantee for the self-heating roasting in the subsequent roasting process, and also creates favorable conditions for the subsequent acid leaching, making the subsequent metal extraction process more efficient. DETAILED DESCRIPTION

[0017] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0018] As described in the background art, the prior art has the problem that it is impossible to extract cobalt and copper from copper-cobalt sulfide concentrates with the characteristics of low sulfur and high copper at a low cost and high leaching rate while maintaining a low leaching rate of iron. In order to solve the above technical problems, the present invention provides a method for leaching copper and cobalt in a high-copper sulfide copper-cobalt concentrate, comprising: step S1, preparing a first slurry with water according to a liquid-solid ratio of (1-4):1 to obtain a first slurry; step S2, performing a first acid leaching on the first slurry for 1h-4h according to an acid-ore ratio of 150kg / t-450kg / t 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 slag; step S4, preparing a second slurry with water according to a liquid-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 650kg / t-1800kg / t to obtain a second leachate.

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

[0020] In the above process, the high-copper copper-cobalt sulfide concentrate is first mixed with water at a liquid-solid ratio of (1-4):1 to prepare the first slurry to ensure that the slurry has sufficient fluidity and provides a good reaction medium for subsequent acid leaching. Then, the acidic environment in the first acid leaching destroys the structure of the copper-cobalt sulfide concentrate, so that copper and cobalt are initially dissolved into the solution, thereby increasing the initial leaching rate of the metal. At the same time, sulfur is released from the mineral and enriched in the first leaching residue, creating conditions for the subsequent self-heating reaction of roasting. The purpose of optimizing the acid-ore ratio and leaching time in the first acid leaching process is to control the degree of iron leaching and avoid excessive iron from entering the subsequent process. Then, the first leaching residue is roasted at a temperature of 650°C to 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 for release, and copper-cobalt oxide is formed, which is convenient for the subsequent acid leaching dissolution. More importantly, the sulfur enriched in the pre-leaching residue burns to provide part of the heat, which helps to achieve the self-heating reaction, reduce the use of external heat sources, and thus significantly reduce energy consumption. Then, the roasted slag and water are mixed at a ratio of (6-10):1 to ensure that the roasted slag has sufficient contact area with the acid solution, promote the dissolution of the metal, and control the concentration of the solution to ensure the leaching efficiency. Finally, the acid leaching conditions are precisely controlled again to achieve the second acid leaching and produce the second leachate. At this time, the oxides converted by roasting are quickly dissolved in the sulfuric acid solution to achieve efficient leaching of copper and cobalt. Since the leaching of iron has been controlled during the first acid leaching process, and roasting further reduces the possibility of iron dissolution, the iron content in the second leachate can be controlled at an extremely low level, reducing the various effects caused by it as an impurity.

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

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

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

[0024] One of the characteristics of the high-copper and low-sulfur copper-cobalt sulfide concentrate treated 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 this condition, the first acid leaching in step S2 is preferably microwave acid leaching, and the microwave power used in 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 rapid molecular vibration, generating a thermal effect and accelerating the reaction. Compared with the external heating of ordinary acid leaching, this direct heating method can more effectively penetrate the interior of the ore particles, promote the rapid decomposition of sulfides even at a lower sulfur content, and improve the leaching rate of copper and cobalt. At the same time, for the ore system treated by the present invention, ordinary acid leaching may be inefficient due to the difficulty of leaching copper sulfides, while in microwave acid leaching, the catalytic effect of microwaves can reduce the reaction activation energy, promote the chemical reaction between copper, cobalt sulfides and acid, and achieve a higher cobalt and copper leaching recovery rate even at a lower leaching temperature.

[0025] In particular, based on the high-copper copper-cobalt sulfide concentrate with special particle size characteristics selected by the present invention, it is further preferred that the microwave power used in microwave preleaching is 500W~1000W, which can more effectively promote 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] In order to achieve better leaching effect by microwave acid leaching, further improve the dissolution rate of cobalt and copper in the process, and accelerate the enrichment of sulfur, it is preferred that in step S2, 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. And it is further preferred that in step S2, the acid-ore ratio used in microwave acid leaching is 200kg / t to 400kg / t, so as to more effectively dissolve copper and cobalt in the ore, and at the same time, adapt to the special conditions of microwave acid leaching to control the consumption of acid, and reduce the problems of excessive dissolution of iron, environmental pollution or cost increase caused by excessive acid leaching.

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

[0028] For the first leached residue with high sulfur content obtained by the first acid leaching, it is preferred that in step S3, the roasting method is fluidized bed roasting, and the air linear velocity used in the fluidized bed roasting is 0.2m / s~0.8m / s, and the air-ore ratio is 0.5m 3 / kg~8.0m 3 / kg. Compared with the conventional roasting method without the use of a fluidized bed roasting furnace, the fluidized bed roasting performed according to the above parameter settings can generate strong gas-solid turbulence, so that the leached slag particles are fully in contact with the air, accelerate the oxidation reaction of the sulfide 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 the sulfide can maintain or even accelerate the roasting process, thereby reducing the consumption of external heat sources and ultimately significantly reducing energy consumption. In addition, the leached slag particles can be more evenly surrounded by hot air in the fluidized bed, which is conducive to the rapid oxidation of sulfides, while also reducing the excessive sintering of metal oxides caused by local overheating, thereby affecting their solubility in the subsequent second acid leaching process. In order to more effectively realize the above process, more effectively reduce energy consumption and improve the total leaching rate of cobalt and copper, it is further preferred that the air linear velocity used in the fluidized bed roasting is 0.3m / s~6m / s, and the wind-ore ratio is 1.0m 3 / kg~5.0m 3 / kg.

[0029] And, it is worth mentioning that the treated raw materials within the above-mentioned particle size range preferred by the present invention have a particularly suitable size range for the leached residue obtained after the first acid leaching, which is easier to disperse in the fluidized bed, thereby forming a more uniform temperature field. During the roasting process, sulfides can be removed more efficiently to generate oxides that are easy to be subsequently acid leached, and finally the leaching rates of cobalt and copper are further improved.

[0030] And, in order to achieve a more ideal desulfurization effect, improve the recovery rate of cobalt and copper in the subsequent second leaching step, and reduce energy consumption and metal oxidation degree, and reduce its loss, it is preferred that the boiling roasting time in step S3 is 1h~3h. Under the above conditions, the total desulfurization rate during the boiling roasting process is 75%~85%, that is, the sulfur removal and efficient utilization of low-sulfur and high-copper sulfide copper-cobalt concentrate is effectively achieved.

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

[0032] In several typical embodiments, the iron content in the second leachate is 0.05g / L~0.11g / L. That is to say, by leaching the high-copper sulfide copper-cobalt concentrate by the above-mentioned 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 effectively reducing the various effects caused by the iron element as an impurity. In particular, if the iron content in the final obtained leachate is high, on the one hand, it will be mixed into the copper and cobalt products during the subsequent purification and recovery process, affecting the quality of the subsequent products and reducing their purity. On the other hand, the subsequent treatment of the copper-cobalt leachate is generally electroplating after extraction, and iron ions may interfere with the solvent extraction process, reduce the extraction efficiency, and affect the recovery rate of copper and cobalt; at the same time, during the electroplating process, the presence of iron ions may cause uneven deposition on the electrode surface, affecting the electroplating efficiency and the quality of subsequent products.

[0033] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0034] Unless otherwise defined, all professional terms used below have the same meanings as those generally 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 scope of protection of the present invention.

[0035] Example 1

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

[0037] A high-copper copper-cobalt sulfide concentrate is provided, the composition and content of which are shown in Table 1, wherein impurity components such as SiO2 are not shown. And, in the processed high-copper copper-cobalt sulfide concentrate, the proportion of the high-copper copper-cobalt sulfide concentrate with a particle size of less than 0.038 mm is 80%.

[0038] Table 1

[0039]

[0040] (1) 100 g of the above-mentioned high-copper copper-cobalt sulfide concentrate is mixed with water to prepare a slurry at a liquid-to-solid ratio of 2:1 to obtain a first slurry.

[0041] (2) The first slurry was subjected to the first acid leaching, i.e., microwave acid leaching, at an acid-ore ratio of 400 kg / t, a temperature of 35°C, and a stirring speed of 500 r / min. The microwave power of the microwave acid leaching was 1000 W, and the microwave preleaching was carried out for 2 hours under this operating condition. After that, the first slurry that had completed the preleaching was subjected to solid-liquid separation to obtain the first leachate and the first leaching slag. In this process, the preleaching slag rate (i.e., the slag discharge rate) was about 70.12%, the copper leaching rate was 31.56%, the cobalt leaching rate was 38.97%, and the iron leaching rate was 48.23%; and the sulfur content in the obtained first leaching slag was 15.69wt%.

[0042] (3) The first leached residue was transferred to a fluidized bed furnace and subjected to oxidative fluidized bed roasting at 750 °C for 2 h. The air velocity used for fluidized bed roasting was 0.45 m / s and the air-to-ore ratio was 3.2 m / s. 3 / kg. In 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) The roasted slag and water are mixed to prepare a slurry at a liquid-to-solid ratio of 8:1 to obtain a second slurry.

[0044] (5) The second ore pulp was subjected to a second acid leaching, i.e., normal pressure leaching, at an acid-ore ratio of 800 kg / t for 120 min to obtain a second leachate having an iron content of 0.069 g / L.

[0045] Example 2

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

[0047] (1) 100 g of the above-mentioned high-copper copper-cobalt sulfide concentrate is mixed with water to prepare a slurry at a liquid-to-solid ratio of 2:1 to obtain a first slurry.

[0048] (2) The first slurry was subjected to the first acid leaching, i.e., microwave acid leaching, at an acid-ore ratio of 200 kg / t, a temperature of 35°C, and a stirring speed of 500 r / min. The microwave power of the microwave acid leaching was 1000 W, and the microwave preleaching was performed for 2 hours under this operating condition. After that, the first slurry that had completed the preleaching was subjected to solid-liquid separation to obtain the first leachate and the first leaching residue. In this process, the preleaching residue rate was about 74.26%, the copper leaching rate was 26.92%, the cobalt leaching rate was 30.26%, and the iron leaching rate was 42.79%; and the sulfur content in the obtained first leaching residue was 15.24wt%.

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

[0050] Example 3

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

[0052] (1) 100 g of the above-mentioned high-copper copper-cobalt sulfide concentrate is mixed with water to prepare a slurry at a liquid-to-solid ratio of 2:1 to obtain a first slurry.

[0053] (2) The first slurry was subjected to the first acid leaching, i.e., microwave acid leaching, at an acid-ore ratio of 200 kg / t, a temperature of 35°C, and a stirring speed of 500 r / min. The microwave power of the microwave acid leaching was 500 W, and the microwave preleaching was performed for 2 hours under this operating condition. After that, the first slurry that had completed the preleaching was subjected to solid-liquid separation to obtain the first leachate and the first leaching residue. In this process, the preleaching residue rate was about 60.14%, the copper leaching rate was 28.31%, the cobalt leaching rate was 32.42%, and the iron leaching rate was 42.53%; and the sulfur content in the obtained first leaching residue was 13.97wt%.

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

[0055] Example 4

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

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

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

[0059] Example 5

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

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

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

[0063] Example 6

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

[0065] The only difference between this embodiment and embodiment 1 is 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 slag 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 the sulfur content in the obtained first leaching slag is 15.43wt%.

[0067] Example 7

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

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

[0070] Example 8

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

[0072] The only difference between this embodiment and embodiment 1 is that the temperature of the fluidized bed 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 sulfide copper-cobalt concentrate:

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

[0076] Example 10

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

[0078] The only difference between this embodiment and embodiment 1 is that the acid-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 sulfide copper-cobalt concentrate:

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

[0082] Example 12

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

[0084] The only difference between this embodiment and embodiment 1 is that the particle size of the processed high-copper copper-cobalt sulfide concentrate 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 sulfide copper-cobalt concentrate:

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

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

[0089] Embodiment 14

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

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

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

[0093] Embodiment 15

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

[0095] The only difference between this embodiment and embodiment 1 is 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 without microwaves.

[0096] Example 16

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

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

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

[0100] Embodiment 17

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

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

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

[0104] Embodiment 18

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

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

[0107] Embodiment 19

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

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

[0110] Embodiment 20

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

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

[0113] In the second acid leaching process of this embodiment, the amount of acid used is significantly increased, which will significantly improve the leaching rate of each element, but the content of impurity iron in the leachate will also increase significantly.

[0114] Comparative Example 1

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

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

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

[0118] Comparative Example 2

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

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

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

[0122] Comparative Example 3

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

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

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

[0126] Comparative Example 4

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

[0128] The only difference between this comparative example and Example 1 is that the temperature of the fluidized bed roasting in step (3) 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 sulfide copper-cobalt concentrate:

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

[0132] (4) The roasted slag and water are mixed to prepare a slurry at a liquid-to-solid ratio of 5:1 to obtain a second slurry.

[0133] (5) The obtained second ore pulp is subjected to second acid leaching, i.e., normal pressure leaching, at an acid-ore ratio of 600 kg / t for 90 min to obtain a second leachate.

[0134] The total leaching rates of Co and Cu in the leaching methods provided in the embodiments and comparative examples are shown in Table 2; the total desulfurization rate during the roasting process is also shown in Table 2; the content of Fe in the final 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 and copper elements in high-copper sulfide copper-cobalt concentrate at a higher leaching rate with lower energy consumption, while ensuring that the iron content in the final leaching solution is lower, the subsequent treatment is simpler, and the application value is higher.

[0138] Specifically, for the special high-copper, low-sulfur copper-cobalt sulfide concentrate, a pre-leaching-roasting-normal pressure leaching combined process is adopted. First, the mineral oxygen is prepared, and the leaching rate of copper and cobalt in the subsequent process is improved by controlling the particle size of the ore particles. Through pre-leaching, copper and cobalt are initially dissolved into the solution by controlling the acid-ore ratio, microwave power, microwave temperature and other conditions, and the initial leaching rate of the metal is improved while enriching the sulfur in the copper-cobalt sulfide concentrate, which is conducive to the self-heating reaction of the roaster, increasing the sulfur dioxide concentration of the flue gas, and providing a guarantee for the self-heating roasting of the subsequent roasting process. And through boiling roasting, a large amount of sulfide in the pre-leaching slag is removed and converted into cobalt-copper oxide that is easily soluble in sulfuric acid solution.

[0139] In particular, Examples 14 and 17 respectively strengthen the microwave power and acid-ore ratio during microwave acid leaching, which exceed the preferred range of the present invention. In this case, the leaching rates of copper and cobalt will be improved, but the iron content in the final leachate will also increase accordingly, which is more unfavorable for the subsequent product processing than Example 1.

[0140] In Example 19, the air linear velocity of the boiling roasting in step (3) is changed to 0.8 m / s, and the air-to-ore ratio is changed to 8.0 m / s. 3 / kg. Under this condition, a higher 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. In other words, although the roasting line speed and wind-ore ratio are optimized, the increase in line speed and wind-ore ratio can increase the boiling roasting effect, the benefit of the increased effect is far less than the investment cost, so the line speed and wind-ore ratio within the preferred range are preferred.

[0141] Finally, through the second acid leaching, the calcined slag and water are mixed in a ratio of (6~10):1, so that the calcined slag and the acid solution have sufficient contact area, which promotes the dissolution of the metal, while controlling the concentration of the solution and improving the leaching efficiency.

[0142] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, 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 description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in 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; 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; 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 high-copper sulfide copper-cobalt concentrate according to claim 1, characterized in that: In step S2, the first acid leaching is microwave acid leaching, and the microwave power used in the microwave acid leaching is 200W~2000W.

4. The method for leaching copper and cobalt from high-copper sulfide copper-cobalt concentrate according to claim 3, characterized in that: In the step S2, the microwave acid leaching is performed at a temperature of 30° C. to 50° C. and a stirring speed of 300 r / min to 700 r / min.

5. The method for leaching copper and cobalt from a high-copper sulfide copper-cobalt concentrate according to any one of claims 1 to 4, characterized in that: The acid-ore ratio in step S2 is 200kg / t to 400kg / t.

6. The method for leaching copper and cobalt from high-copper sulfide copper-cobalt concentrate according to claim 5, characterized in that: In the first leaching residue, the content of sulfur element is 13wt%~18wt%.

7. The method for leaching copper and cobalt from a high-copper sulfide copper-cobalt concentrate according to any one of claims 1 to 4, 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.

8. The method for leaching copper and cobalt from high-copper sulfide copper-cobalt concentrate according to claim 7, characterized in that: In step S3, the time of the fluidized bed roasting is 1 h to 3 h.

9. The method for leaching copper and cobalt from a high-copper sulfide copper-cobalt concentrate according to any one of claims 1 to 4, 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.

10. The method for leaching copper and cobalt from a high-copper sulfide copper-cobalt concentrate according to any one of claims 1 to 4, characterized in that: The iron content in the second leaching solution is 0.05 g / L~0.11 g / L.

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