Method for leaching copper and cobalt from low-sulfur, highcopper copper-cobalt sulfide concentrate

Abstract

A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate, comprising: preparing a first slurry by mixing a high-copper copper-cobalt sulfide concentrate with water according to a liquid-solid ratio of (1-4):1; subjecting the first slurry to first acid leaching for 1-4 h according to an acid-to-ore ratio of 150-450 kg / t, so as to obtain a first leachate and a first leaching residue; roasting the first leaching residue at 650-800℃ to obtain a roasted residue; preparing a second slurry by mixing the roasted residue with water according to a liquid-solid ratio of (6-10):1; and subjecting the second slurry to second acid leaching according to an acid-to-ore ratio of 650-1800 kg / t, so as to obtain a second leachate. The method can effectively reduce the dissolution of iron from the ore, thereby improving the purity of copper and cobalt.

Description

while maintaining a low leaching rate of iron.

[0007] In order to achieve the above purpose, embodiments of the present disclosure provide a method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate, which includes: in S1, preparing a first ore slurry from the high-copper copper-cobalt sulfide concentrate and water in a liquid-to-solid ratio of 1:1 to 4:1; in S2, performing a first acid leaching for 1 h to 4 h on the first ore slurry in an acid-to-ore ratio of 150 kg / t to 450 kg / t to obtain a first leachate and a first leaching residue; in S3, performing a roasting treatment at a temperature of 650 °C to 800 °C on the first leaching residue to obtain a roasted residue; in S4, preparing a second ore slurry from the roasted residue and water in a liquid-to-solid ratio of 6:1 to 10:1; and in S5, performing a second acid leaching on the second ore slurry in an acid-to-ore ratio of 650 kg / t to 1800 kg / t to obtain a second leachate.

[0008] In some embodiments, by weight, 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.

[0009] In some embodiments, in the S2, the first acid leaching is a microwave acid leaching at a microwave power of 200W to 2000W.

[0010] In some embodiments, in the 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.

[0011] In some embodiments, the acid-to-ore ratio in the S2 is 200 kg / t to 400 kg / t.

[0012] In some embodiments, the first leaching residue has a sulfur content of 13 wt% to 18 wt%.

[0013] In some embodiments, in the S3, the roasting treatment is a fluidized bed roasting at an air linear velocity of 0.2 m / s to 0.8 m / s and an air-to-ore ratio of 0.5 m3 / kg to 8.0 m3 / kg.

[0014] In some embodiments, in the S3, the fluidized bed roasting is performed for 1 h to 3 h.

[0015] In some embodiments, in the S5, the acid-to-ore ratio is 700 kg / t to 1500 kg / t, and the second acid leaching is performed for 2 h to 4 h.

[0016] In some embodiments, the second leachate has an iron content of 0.05 g / L to 0.11 g / L.

[0017] By applying the technical solution provided by embodiments of the present disclosure, the leaching rates of cobalt and copper from the high-copper copper-cobalt sulfide concentrate are effectively improved, and the leaching amount of iron is reduced through two-stage acid leaching. Through the intermediate roasting process, sulfur in the high-copper coppercobalt sulfide concentrate is pre-enriched, which is conducive to the self-heating reaction in the roasting process, increasing the sulfur dioxide concentration in the flue gas, and providing a guarantee for the self-heating roasting in the subsequent roasting process. At the same time, it also creates favorable conditions for the subsequent acid leaching, making the subsequent metal extraction process more efficient. DETAILED DESCRIPTION

[0018] It should be noted that, in the absence of conflict, embodiments and features in embodiments of the present disclosure may be combined with each other. The present disclosure will be described in detail below with reference to embodiments.

[0019] As described in the background, there is the problem in the related art that it is impossible to extract cobalt and copper from a copper-cobalt sulfide concentrate with the features 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 problem, embodiments of the present disclosure provide a method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate, which includes: in S1, preparing a first ore slurry from the high-copper coppercobalt sulfide concentrate and water in a liquid-to-solid ratio of 1:1 to 4:1; in S2, performing a first acid leaching for 1 h to 4 h on the first ore slurry in an acid-to-ore ratio of 150 kg / t to 450 kg / t to obtain a first leachate and a first leaching residue; in S3, performing a roasting treatment at a temperature of 650 °C to 800 °C on the first leaching residue to obtain a roasted residue; in S4, preparing a second ore slurry from the roasted residue and water in a liquid-to-solid ratio of 6:1 to 10:1; and in S5, performing a second acid leaching on the second ore slurry in an acid-to-ore ratio of 650 kg / t to 1800 kg / t to obtain a second leachate.

[0020] The above leaching method provided by embodiments of the present disclosure uses a pre-impregnation-roasting atmospheric pressure leaching combined process for special high-copper, low-sulfur copper-cobalt sulfide concentrate. First, a first acid leaching is performed, copper and cobalt in the copper-cobalt sulfide concentrate are preliminarily leached and sulfur in the copper-cobalt sulfide concentrate is enriched, which are conducive to realizing a self-heating reaction of a roaster, increasing a sulfur dioxide concentration in a flue gas, and providing a guarantee for the self-heating roasting in a subsequent roasting process. Afterwards, through a roasting process, a large amount of sulfides in the pre-leaching residue are removed and cobaltcopper oxides that are easily soluble in a sulfuric acid solution are converted into. Finally, through a second acid leaching, a leaching solution with extremely low iron content is obtained.

[0021] In the above process, the high-copper copper-cobalt sulfide concentrate and water are first mixed in a liquid-to-solid ratio of 1:1 to 4:1 to prepare the first ore slurry to ensure that the ore slurry has sufficient fluidity and provides a good reaction medium for the subsequent acid leaching. Then, an acidic environment in the first acid leaching destroys a structure of the coppercobalt sulfide concentrate, causing copper and cobalt to initially dissolve into the solution, thereby increasing an initial 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 subsequent selfheating reaction of roasting. The purpose of optimizing the acid-to-ore ratio and leaching time in the first acid leaching process is to control a degree of iron leaching and avoid excessive iron entering the subsequent processes. The first leaching residue is then roasted at a temperature of 650 °C to 800 °C. The high temperature roasting within this temperature range causes sulfur in the first leaching residue to be fully burned and converted into sulfur dioxide gas for release, and at the same time, copper-cobalt oxides are formed, which facilitates the dissolution of subsequent acid leaching. More importantly, the combustion of sulfur enriched in the pre-leaching residue provides 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 residue and water are mixed in a ratio of 6:1 to 10:1 to ensure that there is sufficient contact area between the roasted residue and the acid solution to promote the dissolution of the metal, while controlling a concentration of the solution to ensure a leaching efficiency. Finally, acid leaching conditions are precisely controlled again to achieve the second acid leaching and produce the second leachate. At this time, oxides converted by roasting are rapidly dissolved in the sulfuric acid solution, achieving efficient leaching of copper and cobalt. Since the leaching of iron has been controlled in the first acid leaching process and a possibility of iron dissolution is further reduced by roasting, the iron content in the second leachate may be controlled at an extremely low level, reducing various effects caused by it as an impurity.

[0022] In summary, the above combined leaching method provided by embodiments of the present disclosure 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 copper-cobalt sulfide concentrate, which may be applied on a large scale with lower environmental and condition requirements.

[0023] In several implementations as examples, 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 leaching method and corresponding parameter conditions, thereby improving the efficiency and selectivity of the above leaching process and ultimately improving the recovery rate of copper and cobalt, a composition of the high-copper copper-cobalt sulfide concentrate is further accurate as follows: that is, by weight, 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.

[0024] In several implementations as examples, for a treated raw material, i.e., the high- copper copper-cobalt sulfide concentrate, the high-copper copper-cobalt sulfide concentrate with a particle size less than 0.038 mm accounts for 70% to 90% based on 100% by weight of the high-copper copper-cobalt sulfide concentrate. This particle size range means that there are more active sites in the high-copper copper-cobalt sulfide concentrate to be processed that may participate in a chemical reaction, thereby increasing the leaching rate of cobalt and copper therein. At the same time, ore materials within this particle size range are more easily penetrated, thereby accelerating a rate of metal dissolution from the ore. At the same time, during a fluidized bed roasting process after the first leaching, the leaching residue formed by a concentrate with the particle size features may be in contact with the air more evenly, promoting a rapid oxidation of sulfides therein. In summary, the inventors have selected, through a large number of experiments, the high-copper copper-cobalt sulfide concentrate with the above particle size features, which may not only improve the leaching rate of cobalt and copper metals and product quality, but also optimize process conditions and bring more significant environmental benefits.

[0025] One of the features of the high-copper, low-sulfur copper-cobalt sulfide concentrate treated by embodiments of the present disclosure is that a sulfur content is relatively low, and the leaching of sulfides is a key step in releasing the copper and cobalt metals. In some embodiments, under this condition, the first acid leaching in the S2 is a microwave acid leaching at a microwave power of 200 W to 2000 W. This is because the microwave acid leaching uses a microwave energy to directly act on polar molecules in the ore, inducing a rapid vibration of the molecules, generating a thermal effect and thus accelerating a reaction. Compared with external heating of an ordinary acid leaching, this direct heating method may more effectively penetrate an interior of ore particles, may promote a rapid decomposition of sulfides even at a low sulfur content, and increase the leaching rate of copper and cobalt. At the same time, for an ore system treated by embodiments of the present disclosure, the ordinary acid leaching may be inefficient due to a difficulty in leaching of copper sulfide, while in the microwave acid leaching, a catalytic effect of microwaves may reduce a reaction activation energy, promote a chemical reaction between copper, cobalt sulfide and acid, and achieve a higher cobalt-copper leaching recovery rate even at a lower leaching temperature.

[0026] In particular, based on the high-copper copper-cobalt sulfide concentrate with special particle size features selected by embodiments of the present disclosure, it is further selected that a microwave power used in a microwave pre-leaching is 500 W to 1000 W, which may more effectively promote a rapid absorption of a microwave energy, thereby accelerating a decomposition of copper and cobalt minerals and an enrichment of sulfur, and ultimately achieving higher leaching rates of cobalt and copper with a lower energy consumption.

[0027] In order to achieve a better leaching effect by the microwave acid leaching, further improve a dissolution rate of cobalt and copper in this process, and accelerate an enrichment of sulfur, in some implementations, in the 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. In some implementations, in the S2, the acid-to-ore ratio used in the 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 adapt to special conditions of the microwave acid leaching to control an acid consumption, thereby reducing problems of excessive iron dissolution, environmental pollution or cost increase caused by an excessive acid leaching.

[0028] In several implementations as examples, after the first acid leaching is completed and the first leaching residue is obtained, a sulfur content in the obtained first leaching residue is 13 wt% to 18 wt%. That is, by optimizing a first acid leaching method and optimizing various condition parameters involved in the optimized microwave acid leaching process, the enrichment of sulfur of an original copper-cobalt sulfide concentrate may be achieved particularly effectively, so that it may be fully burned and provide heat in the subsequent roasting process, promote a realization of the self-heating reaction, reduce the use of external heat sources, and thus more significantly reduce the energy consumption of the overall leaching method.

[0029] For the first leaching residue with a high sulfur content obtained by the first acid leaching, in some implementations, in the S3, the roasting treatment is a fluidized bed roasting at an air linear velocity of 0.2 m / s to 0.8 m / s, and an air-to-ore ratio of 0.5 m3 / kg to 8.0 m3 / kg. Compared with a conventional roasting method without using a fluidized bed roasting furnace, the fluidized bed roasting performed according to the above parameter settings may generate strong gas-solid turbulence, so that leaching residue particles are fully in contact with the air, accelerating an oxidation reaction of sulfides therein and forming SO2 gas, achieving more complete desulfurization in a shorter time, and improving a desulfurization efficiency. During the fluidized bed roasting process, heat released by the oxidation reaction of sulfides may maintain or even accelerate a roasting process, thereby reducing a consumption of external heat sources and ultimately significantly reducing the energy consumption. In addition, the leaching residue particles may be more evenly surrounded by hot air in a fluidized bed, which is conducive to the rapid oxidation of sulfides and also reduces an 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 the energy consumption and improve total leaching rates of cobalt and copper, in some implementations, used in the fluidized bed roasting, the air linear velocity is 0.3 m / s to 6 m / s, and the air-to-ore ratio is 1.0 m3 / kg to 5.0 m3 / kg.

[0030] Further, it is worth mentioning that the treated raw material within the above particle size range preferred by embodiments of the present disclosure has a particularly suitable size range for the leaching 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 may be removed more efficiently to generate oxides that are easy to be subsequently acid leaching, and finally the leaching rate of cobalt and copper are further improved.

[0031] Further, in order to achieve a more ideal desulfurization effect, improve the recovery rate of cobalt and copper in a subsequent second leaching step, and reduce the energy consumption and a metal oxidation degree and its loss, in some implementations, in the S3, the fluidized bed roasting is performed for 1 h to 3 h. Under the above conditions, a total desulfurization rate during the fluidized bed roasting process is 75% to 85%, which effectively realizes the removal and efficient utilization of sulfur in the low-sulfur, high-copper copper-cobalt sulfide concentrate.

[0032] In some implementations, in the S5, the acid-to-ore ratio is 700 kg / t to 1500 kg / t, and the second acid leaching is performed for 2 h to 4 h, so as to more effectively dissolve residual copper and cobalt in the roasted residue and improve its total leaching rate within this acid-to-ore ratio range.

[0033] In several implementations as examples, the second leachate has an iron content of 0.05 g / L to 0.11 g / L. That is, by leaching the high-copper copper-cobalt sulfide concentrate through the above method provided by embodiments of the present disclosure, the dissolution of iron in the ore may be effectively reduced, thereby improving the purity of copper and cobalt, and also effectively reducing various effects caused by iron as an impurity. In particular, if the iron content in a final obtained leachate is high, on the one hand, it may be mixed into copper-cobalt products during a subsequent purification and recovery process, affecting a quality of subsequent products and reducing their purity. On the other hand, a subsequent treatment of the copper-cobalt leachate is generally extraction followed by electro-deposition, and iron ions may interfere with a solvent extraction process, reduce an extraction efficiency, and affect a recovery rate of copper and cobalt; at the same time, during an electrolysis process, the presence of iron ions may cause uneven deposition on an electrode surface, affecting an electrolysis efficiency and subsequent product quality.

[0034] The present disclosure 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 disclosure.

[0035] Unless otherwise defined, all technical terms used hereinafter have the same meanings as commonly understood by those skilled in the art. The technical 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 disclosure.

[0036]       Example 1

[0037] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0038] The high-copper copper-cobalt sulfide concentrate is provided, the composition and content of which are shown in Table 1, and impurity components, such as SiO2, are not shown. Further, in the high-copper copper-cobalt sulfide concentrate processed, the high-copper coppercobalt sulfide concentrate with a particle size less than 0.038 mm accounts for 80%. Table 1 wt.% Cu Co Fe S high-copper copper-cobalt sulfide concentrate 50.21 0.43 3.78 10.87

[0039] (1) 100 g of the above high-copper copper-cobalt sulfide concentrate was mixed with water to prepare an ore slurry in a liquid-to-solid ratio of 2:1 to obtain a first ore slurry.

[0040] (2) The first ore slurry was subjected to a first acid leaching, i.e., a microwave acid leaching, in an acid-to-ore ratio of 400 kg / t, a temperature of 35 °C, and a stirring speed of 500 r / min. A microwave power of the microwave acid leaching was 1000 W, and a microwave preleaching was performed for 2 h under this operating condition. Then, the first ore slurry that had completed pre-leaching was subjected to a solid-liquid separation to obtain a first leachate and a first leaching residue. During this process, a pre-leaching residue rate (i.e., a residue discharge rate) was about 70.12%, a copper leaching rate was 31.56%, a cobalt leaching rate was 38.97%, and an iron leaching rate was 48.23%; and an obtained first leaching residue had a sulfur content of 15.69 wt%.

[0041] (3) The obtained first leaching residue was transferred to a fluidized bed furnace (i.e., a fluidized bed boiler) and subjected to an oxidative fluidized bed roasting at 750 °C for 2 h. Used in the fluidized bed roasting, an air linear velocity was 0.45 m / s and an air-to-ore ratio was 3.2 m3 / kg. During this process, a total desulfurization rate was 77.23% (the total desulfurization rate was calculated according to: (a sulfur content before roasting - a sulfur content after roasting) / the sulfur content before roasting x 100%).

[0042] (4) An obtained roasted residue and water were mixed to prepare an ore slurry in a liquid-to-solid ratio of 8:1 to obtain a second ore slurry.

[0043] (5) An obtained second ore slurry was subjected to a second acid leaching, i.e., an atmospheric pressure leaching, in an acid-to-ore ratio of 800 kg / t for 120 min to obtain a second leachate having an iron content of 0.069 g / L.

[0044]       Example 2

[0045] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0046] (1) 100 g of the above high-copper copper-cobalt sulfide concentrate was mixed with water to prepare an ore slurry in a liquid-to-solid ratio of 2:1 to obtain a first ore slurry.

[0047] (2) The first ore slurry was subjected to a first acid leaching, i.e., a microwave acid leaching, in an acid-to-ore ratio of 200 kg / t, a temperature of 35 °C, and a stirring speed of 500 r / min. A microwave power of the microwave acid leaching was 1000 W, and a microwave preleaching was performed for 2 h under this operating condition. Then, the first ore slurry that had completed pre-leaching was subjected to a solid-liquid separation to obtain a first leachate and a first leaching residue. During this process, a pre-leaching residue rate was about 74.26%, a copper leaching rate was 26.92%, a cobalt leaching rate was 30.26%, and an iron leaching rate was 42.79%; and an obtained first leaching residue had a sulfur content of 15.24 wt%.

[0048] The processing conditions in (3) to (5) were the same as those in Example 1.

[0049]       Example 3

[0050] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0051] (1) 100 g of the above high-copper copper-cobalt sulfide concentrate was mixed with water to prepare an ore slurry in a liquid-to-solid ratio of 2:1 to obtain a first ore slurry.

[0052] (2) The first ore slurry was subjected to a first acid leaching, i.e., a microwave acid leaching, in an acid-to-ore ratio of 200 kg / t, a temperature of 35 °C, and a stirring speed of 500 r / min. A microwave power of the microwave acid leaching was 500 W, and a microwave preleaching was performed for 2 h under this operating condition. Then, the first ore slurry that had completed pre-leaching was subjected to a solid-liquid separation to obtain a first leachate and a first leaching residue. During this process, a pre-leaching residue rate was about 60.14%, a copper leaching rate was 28.31%, a cobalt leaching rate was 32.42%, and an iron leaching rate was 42.53%; and an obtained first leaching residue had a sulfur content of 13.97 wt%.

[0053] The processing conditions in (3) to (5) were the same as those in Example 1.

[0054]       Example 4

[0055] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0056] The difference between this Example and Example 1 is that a liquid-to-solid ratio in an ore slurry preparation process in step (1) was changed to 4:1.

[0057] Under these conditions, obtained in step (2), a pre-leaching residue rate was about 70.12%, a copper leaching rate was 30.12%, a cobalt leaching rate was 31.24%, and an iron leaching rate was 39.27%; and an obtained first leaching residue had a sulfur content of 14.38 wt%.

[0058] Example 5

[0059] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0060] The difference between this Example and Example 1 is that a time of microwave acid leaching in step (2) was changed to 4 h.

[0061] Under these conditions, obtained in step (2), a pre-leaching residue rate was about 70.12%, a copper leaching rate was 32.34%, a cobalt leaching rate was 34.28%, and an iron leaching rate was 47.56%; and an obtained first leaching residue had a sulfur content of 16.27 wt%.

[0062]       Example 6

[0063] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0064] The difference between this Example and Example 1 is that in step (2), a temperature of a microwave acid leaching was changed to 50° C and a stirring speed of the microwave acid leaching was changed to 300 r / min.

[0065] Under these conditions, obtained in step (2), a pre-leaching residue rate was about 72.31%, a copper leaching rate was 30.24%, a cobalt leaching rate was 38.62%, and an iron leaching rate was 47.23%; and an obtained first leaching residue had a sulfur content of 15.43 wt%.

[0066]       Example 7

[0067] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0068] The difference between this Example and Example 1 is that in step (3), an air linear velocity of a fluidized bed roasting was changed to 0.6 m / s, and an air-to-ore ratio of the fluidized bed roasting was changed to 5 m3 / kg.

[0069]       Example 8

[0070] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0071] The difference between this Example and Example 1 is that in step (3), a temperature of a fluidized bed roasting was changed to 800 °C and a time of the fluidized bed roasting was changed to 3 h.

[0072]       Example 9

[0073] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0074] The difference between this Example and Example 1 is that a liquid-to-solid ratio in an ore slurry preparation process in step (4) was changed to 10:1.

[0075]       Example 10

[0076] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0077] The difference between this Example and Example 1 is that an acid-to-ore ratio of a second acid leaching in step (5) was changed to 1500 kg / t.

[0078]       Example 11

[0079] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0080] The difference between this Example and Example 1 is that a leaching time of a second acid leaching in step (5) was changed to 4 h.

[0081]       Example 12

[0082] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0083] The difference between this Example and Example 1 is that a particle size of the high-copper copper-cobalt sulfide concentrate processed was changed to make the high-copper copper-cobalt sulfide concentrate with a particle size less than 0.038 mm therein account for 50%.

[0084] Example 13

[0085] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0086] The difference between this Example and Example 1 is that a microwave power of a microwave acid leaching in step (2) was changed to 200 W.

[0087] Under these conditions, obtained in step (2), a pre-leaching residue rate was about 75.28%, a copper leaching rate was 28.01%, a cobalt leaching rate was 31.23%, and an iron leaching rate was 40.24%; and an obtained first leaching residue had a sulfur content of 17.92 wt%.

[0088] Example 14

[0089] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0090] The difference between this Example and Example 1 is that a microwave power of a microwave acid leaching in step (2) was changed to 2000 W.

[0091] Under these conditions, obtained in step (2), a pre-leaching residue rate was about 59.23%, a copper leaching rate was 28.51%, a cobalt leaching rate was 32.07%, and an iron leaching rate was 45.23%; and an obtained first leaching residue had a sulfur content of 12.89 wt%.

[0092] Example 15

[0093] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0094] The difference between this Example and Example 1 is that a microwave power of a microwave acid leaching in step (2) was changed to 0 W, that is, a first acid leaching was performed without microwaves.

[0095]       Example 16

[0096] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[0097] The difference between this Example and Example 1 is that an acid-to-ore ratio of a microwave acid leaching in step (2) was changed to 150 kg / t.

[0098] Under these conditions, obtained in step (2), a pre-leaching residue rate was about 74.34%, a copper leaching rate was 27.72%, a cobalt leaching rate was 30.24%, and an iron leaching rate was 40.27%; and an obtained first leaching residue had a sulfur content of 18.23 wt%.

[0099] Example 17

[00100] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[00101] The difference between this Example and Example 1 is that an acid-to-ore ratio of a microwave acid leaching in step (2) was changed to 450 kg / t.

[00102] Under these conditions, obtained in step (2), a pre-leaching residue rate was about 69.95%, a copper leaching rate was 28.46%, a cobalt leaching rate was 31.29%, and an iron leaching rate was 42.86%; and an obtained first leaching residue had a sulfur content of 14.23 wt%.

[00103] Example 18

[00104] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[00105] The difference between this Example and Example 1 is that in step (3), an air linear velocity of a fluidized bed roasting was changed to 0.2 m / s, and an air-to-ore ratio of the fluidized bed roasting was changed to 0.5 m3 / kg.

[00106]      Example 19

[00107] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[00108] The difference between this Example and Example 1 is that in step (3), an air linear velocity of a fluidized bed roasting was changed to 0.8 m / s, and an air-to-ore ratio of the fluidized bed roasting was changed to 8.0 m3 / kg.

[00109]      Example 20

[00110] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[00111] The difference between this Example and Example 1 is that an acid-to-ore ratio of a second acid leaching in step (5) was changed to 1800 kg / t.

[00112] In a second acid leaching process of this example, an amount of acid used was significantly increased, which may significantly improve a leaching rate of each element, but a content of impurity iron in the leachate may also increase substantially.

[00113]      Comparative Example 1

[00114] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[00115] The difference between this Comparative Example and Example 1 is that an acid- to-ore ratio of a microwave acid leaching in step (2) was changed to 100 kg / t.

[00116] Under these conditions, obtained in step (2), a pre-leaching residue rate was about 87.34%, a copper leaching rate was 12.57%, a cobalt leaching rate was 18.65%, and an iron leaching rate was 23.57%; and an obtained first leaching residue had a sulfur content of 14.56 wt%.

[00117] Comparative Example 2

[00118] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[00119] The difference between this Comparative Example and Example 1 is that a liquid- to-solid ratio in an ore slurry preparation process in step (1) was changed to 6:1.

[00120] Under these conditions, obtained in step (2), a pre-leaching residue rate was about 82.15%, a copper leaching rate was 26.57%, a cobalt leaching rate was 29.36%, and an iron leaching rate was 32.12%; and an obtained first leaching residue had a sulfur content of 13.38 wt%.

[00121] Comparative Example 3

[00122] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[00123] The difference between this Comparative Example and Example 1 is that a time of a microwave acid leaching in step (2) was changed to 40 min.

[00124] Under these conditions, obtained in step (2), a pre-leaching residue rate was about 82.56%, a copper leaching rate was 25.52%, a cobalt leaching rate was 28.32%, and an iron leaching rate was 31.13%; and an obtained first leaching residue had a sulfur content of 11.37 wt%.

[00125] Comparative Example 4

[00126] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[00127] The difference between this Comparative Example and Example 1 is that in step (3), a temperature of a fluidized bed roasting was changed to 600 °C and a time of the fluidized bed roasting was changed to 1 h.

[00128]      Comparative Example 5

[00129] A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate was performed as follows.

[00130] The difference between this Comparative Example and Example 1 lie in step (4) and step (5), which are as follows.

[00131] (4) An obtained roasted residue and water were mixed to prepare an ore slurry in a liquid-to-solid ratio of 5:1 to obtain a second ore slurry.

[00132] (5) An obtained second ore slurry was subjected to a second acid leaching, i.e., an atmospheric pressure leaching, in an acid-to-ore ratio of 600 kg / t for 90 min to obtain a second leachate.

[00133] Total leaching rates of Co and Cu in the leaching methods provided by Examples and Comparative Examples are shown in Table 2; total desulfurization rates in the roasting process are also shown in Table 2; and Fe contents in final obtained leachates are also shown in Table 2. Table 2 Total desulfurization rate in a roasting process (%) Fe content in final obtained leachate (g / L) Total leaching rate of Cu (%) Total leaching rate of Co (%) Example 1 77.23 0.069 98.80 99.01 Example 2 78.21 0.073 98.23 98.72 Example 3 75.33 0.072 98.52 98.91 Example 4 78.33 0.084 97.98 98.21 Example 5 77.85 0.085 98.08 98.44 Example 6 77.57 0.071 98.56 98.93 Example 7 80.32 0.071 98.90 99.01 Example 8 80.01 0.059 99.02 99.51 Example 9 77.23 0.082 98.45 98.21 Example 10 77.28 0.062 99.78 99.49 Example 11 77.04 0.062 99.22 99.34 Example 12 75.06 0.090 97.23 98.02 Example 13 75.38 0.085 98.01 96.23 Example 14 77.13 0.092 98.27 99.21 Example 15 74.89 0.098 93.45 94.56 Example 16 75.27 0.089 97.25 97.89 Example 17 77.92 0.094 98.03 98.94 Example 18 77.14 0.084 97.75 98.11 Example 19 77.53 0.081 98.72 99.02 Example 20 78.23 0.110 98.91 99.32 Comparative Example 1 74.34 0.240 91.24 92.31 Comparative Example 2 74.21 0.150 91.82 90.57 Comparative Example 3 72.27 0.130 90.23 91.80 Comparative Example 4 62.17 0.450 90.12 89.23 Comparative Example 5 74.23 0.920 85.33 86.12

[00134] From the above description, it can be seen that the above Examples of the present disclosure achieve the extraction of cobalt and copper from the high-copper copper-cobalt sulfide concentrate at a higher leaching rate with a lower energy consumption, while ensuring that the iron content in the final obtained leachate is lower, a subsequent treatment is simpler, and an application value is higher.

[00135] Specifically, for a special high-copper, low-sulfur copper-cobalt sulfide concentrate, a pre-leaching-roasting-atmospheric pressure leaching combined process is used. First, ore oxygen is prepared, and the leaching rates of copper and cobalt in the subsequent process are improved by controlling a particle size of ore particles. Through pre-leaching, by controlling the acid-to-ore ratio, microwave power, microwave temperature and other conditions, copper and cobalt are initially dissolved into the solution, thereby increasing the initial leaching rate of metals and enriching sulfur in the copper-cobalt sulfide concentrate, which is conducive to the self-heating reaction of the roaster, increasing the sulfur dioxide concentration in the flue gas, and providing a guarantee for the self-heating roasting in the subsequent roasting process. And through the fluidized bed roasting, a large amount of sulfides in the pre-leaching residue are removed and cobalt-copper oxides that are easily soluble in the sulfuric acid solution are converted into.

[00136] In particular, in Examples 14 and 17, the microwave power and the acid-to-ore ratio in the microwave acid leaching process are strengthened respectively, which are beyond the preferred range of embodiments of the present disclosure. In this case, the leaching rates of copper and cobalt may be improved, but the iron content in the final leachate may also increase accordingly, which is more unfavorable for the subsequent product processing compared with Example 1.

[00137] In Example 19, in step (3), the air linear velocity of the fluidized bed roasting is changed to 0.8 m / s, and the air-to-ore ratio of the fluidized bed roasting is changed to 8.0 m3 / kg. Under these conditions, a higher leaching rate of copper and cobalt may also be obtained. However, since the increase in process parameters may lead to an increase in the corresponding energy consumption, the overall economic benefit is slightly worse than that of Example 1. That is, the linear velocity and air-to-ore ratio of roasting are optimized. Although increasing the linear velocity and the air-to-ore ratio may increase a fluidized bed roasting effect, benefits of the increased effect are far less than an investment cost. Therefore, the linear velocity and the air-to-ore ratio are preferably within the range.

[00138] Finally, through the second acid leaching, the roasted residue and water are mixed in a ratio of 6:1 to 10:1, so that the roasted residue and the acid solution have sufficient contact area, which promotes the dissolution of metals, while controlling the concentration of the solution and improving the leaching efficiency.

[00139] It should be noted that terms “first”, “second”, etc. in the description and claims of the present disclosure are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It is to be understood that the terms so used may be interchangeable where appropriate, such that implementations of the present disclosure described herein may, for example, be implemented in an order other than those described herein.

[00140] The above descriptions are only preferred embodiments of the present disclosure and are not intended to limit the present disclosure. For those skilled in the art, the present disclosure may be subject to various modifications and changes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A method for leaching copper and cobalt from a high-copper copper-cobalt sulfide concentrate, comprising:in S1, preparing a first ore slurry from the high-copper copper-cobalt sulfide concentrate and water in a liquid-to-solid ratio of 1:1 to 4:1;in S2, performing a first acid leaching for 1 h to 4 h on the first ore slurry in an acid-to-ore ratio of 150 kg / t to 450 kg / t to obtain a first leachate and a first leaching residue;in S3, performing a roasting treatment at a temperature of 650 °C to 800 °C on the first leaching residue to obtain a roasted residue;in S4, preparing a second ore slurry from the roasted residue and water in a liquid-to-solid ratio of 6:1 to 10:1; andin S5, performing a second acid leaching on the second ore slurry in an acid-to-ore ratio of 650 kg / t to 1800 kg / t to obtain a second leachate.

2. The method for leaching copper and cobalt from the high-copper copper-cobalt sulfide concentrate according to claim 1, wherein, by weight, the high-copper copper-cobalt sulfide concentrate comprises 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.

3. The method for leaching copper and cobalt from the high-copper copper-cobalt sulfide concentrate according to claim 1 or claim 2, wherein in the S2, the first acid leaching is a microwave acid leaching at a microwave power of 200 W to 2000 W.

4. The method for leaching copper and cobalt from the high-copper copper-cobalt sulfide concentrate according to claim 3, wherein in the 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 the high-copper copper-cobalt sulfide concentrate according to any one of claims 1 to 4, wherein the acid-to-ore ratio in the S2 is 200 kg / t to 400 kg / t.

6. The method for leaching copper and cobalt from the high-copper copper-cobalt sulfide concentrate according to any one of claims 1 to 5, wherein the first leaching residue has a sulfur content of 13 wt% to 18 wt%.

7. The method for leaching copper and cobalt from the high-copper copper-cobalt sulfide concentrate according to any one of claims 1 to 6, wherein in the S3, the roasting treatment is a fluidized bed roasting at an air linear velocity of 0.2 m / s to 0.8 m / s and an air-to-ore ratio of 0.5 m3 / kg to 8.0 m3 / kg.

8. The method for leaching copper and cobalt from the high-copper copper-cobalt sulfide concentrate according to claim 7, wherein in the S3, the fluidized bed roasting is performed for 1 h to 3 h.

9. The method for leaching copper and cobalt from the high-copper copper-cobalt sulfide concentrate according to any one of claims 1 to 8, wherein in the S5, the acid-to-ore ratio is 700 kg / t to 1500 kg / t, and the second acid leaching is performed for 2 h to 4 h.

10. The method for leaching copper and cobalt from the high-copper copper-cobalt sulfide concentrate according to any one of claims 1 to 9, wherein the second leachate has an iron content of 0.05 g / L to 0.11 g / L.