Process for extracting nickel and copper from nickel oxide copper ore

Abstract

The invention discloses a process for extracting nickel and copper from nickel oxide copper ore. The process comprises the following steps: S1, adding water or a second-stage leaching solution into nickel oxide copper ore powder for pulping, adding concentrated sulfuric acid for curing reaction, and adding the second-stage leaching solution again for first-stage leaching reaction to form first-stage leaching slurry; s2, thickening the first-section leaching slurry to obtain a thick supernatant and a thick underflow; stirring, grinding and activating the dense underflow, adding concentrated sulfuric acid to carry out a first-stage leaching reaction, and carrying out thickening and filter pressing to obtain a second-stage leaching solution and leaching residues; s3, metal iron is added into the dense supernatant for a replacement reaction, and a replaced solution and sponge copper are obtained; s4, a neutralizer is added into the replaced liquid for jet flow oxidation iron removal, and iron removal liquid and iron removal slag are obtained through filtering; and S5, adding an alkaline solution into the iron removal liquid for precipitation, and filtering to obtain a nickel hydroxide product and a nickel precipitation liquid. The method is short in technological process, low in nickel-copper leaching rate, low in cost and high in ore source adaptability.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical process, and relates to a process for extracting nickel and copper from nickel-copper oxide ore, and in particular to a method for smelting and extracting complex nickel-copper oxide ore. Background Art

[0002] Most of the copper and nickel in weathered or semi-weathered nickel-oxide copper ore are in an oxidized state, but about 40% of the copper is still in the form of sulfide. The ore is a difficult-to-select and difficult-to-smelt ore with a high silicate content, and it is very difficult to select and smelt. Conventional leaching processes are difficult to achieve a good leaching rate. Patent CN114672641B, a combined process for the selection and smelting of difficult-to-select impregnated copper-nickel oxide ore, provides a selection and smelting process for difficult-to-select impregnated copper-nickel oxide ore. The process has a long leaching time and a low copper-nickel leaching rate. Therefore, the market is in urgent need of a nickel-oxide copper ore extraction process that can improve the copper-nickel leaching rate. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art, and to provide a process for extracting nickel and copper from nickel-copper oxide ores in view of the problem that complex nickel-copper oxide ores are difficult to select and smelt. The present invention improves the copper-nickel leaching rate by combining a two-stage countercurrent leaching process with a high-temperature maturation process. However, based on research findings, a large portion of copper and nickel are still difficult to leach after a stage of maturation leaching due to reasons such as the wrapped oxidation state. Therefore, the present invention innovatively designs a stirring mill activation after a stage of maturation leaching, and further activates a stage of leachate, which is conducive to achieving a high leaching rate while shortening the process flow and ensuring efficiency, and solves the problem of economical and efficient smelting of low-grade complex mineral phase nickel-copper oxide ores. The process has the characteristics of high nickel-copper leaching rate, high leaching efficiency, low iron removal process cost, simple process operation, and good comprehensive benefits.

[0004] The purpose of the present invention can be achieved by the following scheme:

[0005] In a first aspect, the present invention provides a method for extracting nickel and copper from nickel-copper oxide ore, comprising the following steps:

[0006] S1, primary leaching: adding the secondary leaching solution to the nickel copper oxide ore powder for slurrying, adding concentrated sulfuric acid for aging reaction, adding the secondary leaching solution again for primary leaching reaction, and forming a primary leaching slurry;

[0007] Water is used for the first beating, and the second-stage leachate is used for subsequent beating;

[0008] S2, second stage leaching: the first stage leaching slurry is thickened to obtain a thick supernatant and a thick underflow; the thick underflow is activated by a stirring mill, and then concentrated sulfuric acid is added to carry out a second stage leaching reaction, and then thickened and filtered to obtain a second stage leaching liquid and a leaching residue;

[0009] S3, replacing copper: adding metallic iron to the concentrated supernatant of step S2 to carry out a replacement reaction to obtain a replaced liquid and sponge copper;

[0010] S4, jet iron removal: adding a neutralizing agent to the replaced liquid in step S3 to perform jet oxidation iron removal, and filtering to obtain iron removal liquid and iron removal slag;

[0011] S5, nickel precipitation: adding alkaline solution to the iron removal solution in step S4 for precipitation, filtering to obtain a nickel hydroxide product and a nickel precipitation solution.

[0012] As an embodiment of the present invention, in step S1, the method for preparing the nickel copper oxide ore powder comprises: dry grinding the nickel copper oxide ore to obtain the nickel copper oxide ore powder; the nickel copper oxide ore powder has a fineness of 180-210 mesh accounting for more than 80wt.%.

[0013] Furthermore, the nickel copper oxide ore includes the following components in weight percentage: 0.4-0.8% nickel, 0.7-1.5% copper, 0.5-3% aluminum, 5-15% magnesium, 10-20% silicon, and the rest are impurities, including oxygen and sulfur.

[0014] The present invention adopts a two-stage countercurrent leaching process, and the second-stage leaching solution used in step S1 is the second-stage leaching solution produced in step S2.

[0015] As an embodiment of the present invention, in step S1, the mass ratio of the second-stage leaching solution to the nickel copper oxide ore powder is 0.2-0.8:1, preferably 0.5:1.

[0016] As an embodiment of the present invention, in step S1, the mass ratio of the concentrated sulfuric acid to the nickel copper oxide ore powder is 0.3-0.5: 1. In some embodiments, the mass percentage of the concentrated sulfuric acid is 98%.

[0017] As an embodiment of the present invention, in step S1, the temperature of the aging reaction is 110-120° C., and the time is 0.5-1.5 h. The aging temperature is preferably 110° C. 98% concentrated sulfuric acid is preferred to increase the aging temperature. If the aging temperature is too low, the leaching rate will be reduced.

[0018] As an embodiment of the present invention, in step S1, the mass ratio of the second-stage leaching solution added again to the nickel copper oxide ore powder is 3-4:1; the temperature of the first-stage leaching reaction is 60-80°C, and the time is 1-2 hours. Preferably, it is 3.5:1.

[0019] The present invention achieves a nickel leaching rate of more than 80% and a copper leaching rate of more than 85% through a one-stage ripening leaching.

[0020] In some embodiments, thickening is performed in a thickener.

[0021] As an embodiment of the present invention, in step S2, the solid content of the dense underflow is 35-50%.

[0022] As an embodiment of the present invention, in step S2, the stirring mill activation time is 0.3 to 1 hour. The use of the stirring mill is based on the difficult leaching properties of the copper-nickel oxide ore and the process requirements of the two-stage countercurrent leaching. Further activation of the first-stage leachate is conducive to achieving a high leaching rate while shortening the process flow and ensuring efficiency. If the stirring mill activation is performed before the first-stage maturation leaching, the leaching rate cannot be significantly improved.

[0023] As an embodiment of the present invention, in step S2, the volume ratio of the thickened underflow to concentrated sulfuric acid is 0.05-0.2:1; the temperature of the second-stage leaching reaction is 60-80°C, and the time is 1-2h. In step S2 of the present invention, after the second-stage leaching reaction, the thickening is performed to obtain a second-stage leaching solution and a second-stage leaching underflow; and the second-stage leaching underflow is then filtered to obtain a second-stage leaching solution and leaching residue.

[0024] As an embodiment of the present invention, in step S3, the mass ratio of the metallic iron to the copper in the concentrated supernatant is 1-1.5:0.8-1.0, preferably 1.2:1. The metallic iron includes iron powder or iron plate.

[0025] As an embodiment of the present invention, in step S3, the replacement reaction time is 0.6 to 1 h.

[0026] As an embodiment of the present invention, in step S4, the neutralizing agent includes any one of lime powder and slaked lime, and the neutralizing agent is added to a pH of 3.0-4.0.

[0027] As an embodiment of the present invention, in step S4, the jet oxidation deironing is carried out in air; the temperature of the jet oxidation deironing is 75-90°C, and the time is 4-5.5h.

[0028] As an embodiment of the present invention, in step S5, the alkaline solution includes a sodium hydroxide solution.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The present invention utilizes concentrated sulfuric acid to perform high-temperature aging in the first stage of leaching to dissociate the difficult-to-leach nickel and copper, thereby realizing efficient leaching of nickel and copper in the difficult-to-leach ore phase; further based on research findings, a large portion of copper and nickel in the first stage of leaching solution after aging leaching is still difficult to leach due to reasons such as the wrapped oxidation state, so the present invention innovatively designs a stirring mill activation after the first stage of aging leaching to further activate the first stage of leaching solution, which is beneficial to achieving a high leaching rate under the premise of shortening the process flow and ensuring efficiency, so that the full-process leaching rate of nickel in the second stage countercurrent leaching is greater than 95%, and the full-process leaching rate of copper is greater than 97%.

[0031] 2. The present invention adopts a two-stage countercurrent leaching process, which controls the supernatant of the first leaching by the second-stage countercurrent leaching, and can effectively reduce the leaching of impurities such as impurity iron. The process operation is simple, the leaching efficiency is high, and it is suitable for industrial large-scale production.

[0032] 3. The present invention adopts air jet oxidation iron removal technology to achieve efficient mixing of gas, liquid and solid three phases through an ejector, thereby improving the contact reaction efficiency of gas, liquid and solid, thereby achieving the purpose of improving oxygen utilization, shortening oxidation time, and achieving rapid and low-cost iron removal and energy saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0034] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0035] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The following examples are implemented on the premise of the technical solution of the present invention, provide detailed implementation methods and specific operation processes, and will help those skilled in the art to further understand the present invention. It should be pointed out that the protection scope of the present invention is not limited to the following embodiments, and several adjustments and improvements made under the premise of the concept of the present invention all belong to the protection scope of the present invention.

[0036] Example 1

[0037] refer to Figure 1 The process flow shown in the figure, this embodiment provides a process for extracting nickel and copper from nickel-copper oxide ore, comprising the following steps:

[0038] (1) Grinding: The raw ore with nickel content of 0.56%, copper content of 1.01%, aluminum content of 2.1%, silicon content of 15.3%, and the rest of oxygen and sulfur impurities is ground into a fineness of -200 mesh and 80wt.% ore powder.

[0039] (2) Primary leaching: 10 kg of the obtained mineral powder was put into a primary reaction tank, 5 kg of the secondary leaching solution was added at a liquid-solid ratio of 0.5:1 for slurrying, and then 3 kg of 98% concentrated sulfuric acid was added at an acid-ore ratio of 0.3:1, stirred and aged at 115°C for 1 hour, and then 35 kg of the secondary leaching solution was added at a liquid-solid ratio of 3.5:1 for a second time, and the stirring reaction was continued for 1.1 hours; water was used for the first slurrying, and the secondary leaching solution was used for the subsequent slurrying;

[0040] (3) Stirred mill activation, second-stage leaching and filter press: The first-stage leaching slurry is pumped into a thickener for thickening, and the thick underflow (solid content is 40%) is discharged into the stirred mill for grinding and activation for 0.4 hours and then discharged into the second-stage leaching tank. Concentrated sulfuric acid is added at an underflow volume ratio of 0.1:1 for second-stage leaching. The reaction is stirred at 65°C for 1 hour. After the second-stage leaching is completed, it is pumped into a thickener for thickening. The thick supernatant is the second-stage leaching liquid. The thick underflow is filtered, and the filter press residue is sold for external treatment;

[0041] (4) Copper replacement: the concentrated supernatant of the first leaching slurry is added with iron powder or iron plate at a ratio of 1.2:1 to copper and subjected to replacement reaction for 0.6 h to obtain sponge copper;

[0042] (5) Jet deironing: Use an ejector to jet oxidize the replaced liquid with air for deironing. The reaction temperature is controlled at 80°C and the reaction time is 4.8 hours. Lime powder is added as a neutralizer to control the pH to 3.5. The iron content of the liquid after deironing is 0.5 g / L. After deironing, filter to obtain deironing liquid and deironing slag.

[0043] (6) nickel precipitation: adding the iron removal liquid to a 1.5 mol / L sodium hydroxide solution at a pH of 8.0 to precipitate nickel, and filtering to obtain a nickel hydroxide product and a nickel precipitation liquid;

[0044] The final copper leaching rate is 97.5%, and a sponge copper with a grade of 98.26% can be obtained; the nickel leaching rate is 95.4%, and a nickel hydroxide grade of 21.46% can be obtained.

[0045] Example 2

[0046] A process for extracting nickel and copper from nickel-copper oxide ore comprises the following steps:

[0047] (1) Grinding: Grind the raw ore with nickel content of 0.75%, copper content of 1.2%, aluminum content of 2.0%, silicon content of 15.1%, and the rest of oxygen and sulfur impurities to a fineness of -200 mesh and 80% of the ore powder.

[0048] (2) Primary leaching: 10 kg of the obtained mineral powder was put into the primary reaction tank, 5 kg of the secondary leaching solution was added at a liquid-solid ratio of 0.5:1 for slurrying, and then 5 kg of concentrated sulfuric acid was added at an acid-ore ratio of 0.5:1 at 110°C for stirring and aging for 1.4 h, and then 35 kg of the secondary leaching solution was added for a second time at a liquid-solid ratio of 3.5:1 and continued to stir and react for 1.5 h; water was used for the first slurrying, and the secondary leaching solution was used for the subsequent slurrying;

[0049] (3) Stirred mill activation, second-stage leaching and filter press: The first-stage leaching slurry is pumped into a thickener for thickening, and the thick underflow (solid content is 40%) is discharged into the stirred mill for grinding and activation for 1 hour and then discharged into the second-stage leaching tank. Sulfuric acid is added at an underflow volume ratio of 0.2:1 for second-stage leaching, and the reaction is controlled at 75°C for stirring for 2 hours. After the second-stage leaching is completed, it is pumped into a thickener for thickening. The thick supernatant is the second-stage leaching liquid, and the thick underflow is filtered, and the filter press residue is sold for external treatment;

[0050] (4) Copper replacement: the concentrated supernatant of the first leaching slurry is added with iron powder or iron plate at a ratio of 1.2:1 to copper and the replacement reaction is carried out for 0.8 h to obtain sponge copper;

[0051] (5) Jet deironing: Use an ejector to jet oxidize the replaced liquid with air to remove iron. The reaction temperature is controlled to 85°C and the reaction time is 4 hours. Lime powder is added as a neutralizer to control the pH to 4.0. The iron content of the liquid after deironing is 0.4 g / L. After deironing, filter to obtain deironing liquid and deironing slag.

[0052] (6) nickel precipitation: adding the iron removal liquid to a 2.5 mol / L sodium hydroxide solution at a pH of 8.5 to precipitate nickel, and filtering to obtain a nickel hydroxide product and a nickel precipitation liquid;

[0053] The final copper leaching rate is 98.0%, and a sponge copper with a grade of 98.86% can be obtained; the nickel leaching rate is 96.2%, and a nickel hydroxide grade of 22.35% can be obtained.

[0054] Example 3

[0055] A process for extracting nickel and copper from nickel-copper oxide ore comprises the following steps:

[0056] (1) Grinding: The raw ore with nickel content of 0.51%, copper content of 0.96%, aluminum content of 2.4%, silicon content of 15.2%, and the rest of oxygen and sulfur impurities is ground to a fineness of -200 mesh and 80% of the ore powder.

[0057] (2) Primary leaching: 10 kg of the obtained mineral powder was put into the primary reaction tank, 5 kg of the secondary leaching solution was added at a liquid-solid ratio of 0.5:1 for slurrying, and then 4 kg of concentrated sulfuric acid was added at an acid-ore ratio of 0.4:1, stirred and aged at 120°C for 0.6 h, and then 35 kg of the secondary leaching solution was added for a second time at a liquid-solid ratio of 3.5:1 and continued to stir and react for 1.2 h; water was used for the first slurrying, and the secondary leaching solution was used for the subsequent slurrying;

[0058] (3) Stirred mill activation, second-stage leaching and filter press: The first-stage leaching slurry is pumped into a thickener for thickening, and the thick underflow (solid content is 40%) is discharged into the stirred mill for grinding and activation for 1 hour and then discharged into the second-stage leaching tank. Sulfuric acid is added at an underflow volume ratio of 0.06:1 for second-stage leaching, and the reaction is stirred at 80°C for 1 hour. After the second-stage leaching is completed, it is pumped into a thickener for thickening. The thick supernatant is the second-stage leaching liquid, and the thick underflow is filtered, and the filter press residue is sold for external treatment;

[0059] (4) Copper replacement: the concentrated supernatant of the first leaching slurry is added with iron powder or iron plate at a ratio of 1.2:1 to copper and subjected to replacement reaction for 0.1 h to obtain sponge copper;

[0060] (5) Jet deironing: Use an ejector to jet oxidize the replaced liquid with air for deironing. The reaction temperature is controlled at 90°C for 3 hours. Lime powder is added as a neutralizer to control the pH to 3.0. The iron content of the liquid after deironing is 0.8 g / L. After deironing, filter to obtain deironing liquid and deironing slag.

[0061] (6) nickel precipitation: adding the iron removal liquid to a 3.0 mol / L sodium hydroxide solution at a pH of 8.9 to precipitate nickel, and filtering to obtain a nickel hydroxide product and a nickel precipitation liquid;

[0062] The final copper leaching rate is 97.65%, and a sponge copper with a grade of 98.16% can be obtained; the nickel leaching rate is 95.82%, and a nickel hydroxide grade of 22.63% can be obtained.

[0063] Comparative Example 1

[0064] The method of this comparative example is basically the same as that of Example 1, except that the grinding and activation step is omitted in step (3), as follows:

[0065] (3) The first-stage leaching slurry is pumped into a thickener for thickening, and concentrated sulfuric acid is added to the thick underflow (solid content is 40%) at an underflow volume ratio of 0.1:1 for second-stage leaching. The reaction is controlled at 65° C. and stirred for 1 hour. After the second-stage leaching is completed, it is pumped into a thickener for thickening. The thick supernatant is the second-stage leaching liquid. The thick underflow is filtered, and the filter residue is sold for external treatment;

[0066] The final copper leaching rate is 89.05%, and a sponge copper with a grade of 98.01% can be obtained; the nickel leaching rate is 87.21%, and a nickel hydroxide grade of 21.67% can be obtained.

[0067] Comparative Example 2

[0068] The method of this comparative example is basically the same as that of Example 1, except that a stirring mill activation is performed before the first stage of ripening and leaching, as follows:

[0069] (2) 10 kg of the obtained mineral powder was put into a first-stage reaction tank, 5 kg of the second-stage leaching solution was added at a liquid-solid ratio of 0.5:1 for slurrying, and then discharged into a stirred mill for grinding and activation for 0.4 h, and then 3 kg of 98% concentrated sulfuric acid was added at an acid-ore ratio of 0.3:1 and stirred and aged at 115°C for 1 h, and then 35 kg of the second-stage leaching solution was added for a second time at a liquid-solid ratio of 3.5:1 and continued to stir and react for 1.1 h; water was used for the first slurrying, and the second-stage leaching solution was used for subsequent slurrying;

[0070] (3) The first-stage leaching slurry is pumped into a thickener for thickening, and concentrated sulfuric acid is added to the thick underflow (solid content is 40%) at an underflow volume ratio of 0.1:1 for second-stage leaching. The reaction is controlled at 65° C. and stirred for 1 hour. After the second-stage leaching is completed, it is pumped into a thickener for thickening. The thick supernatant is the second-stage leaching liquid. The thick underflow is filtered, and the filter residue is sold for external treatment;

[0071] The final copper leaching rate is 90.53%, and a sponge copper with a grade of 97.89% can be obtained; the nickel leaching rate is 88.45%, and a nickel hydroxide grade of 21.87% can be obtained.

[0072] Comparative Example 3

[0073] The method of this comparative example is basically the same as that of Example 1, except that the aging temperature in step (3) is 100° C., as follows:

[0074] (2) 10 kg of the obtained mineral powder was put into a first-stage reaction tank, 5 kg of the second-stage leaching solution was added at a liquid-solid ratio of 0.5:1 for slurrying, and then 3 kg of 98% concentrated sulfuric acid was added at an acid-ore ratio of 0.3:1, stirred and aged at 100°C for 1 hour, and then 35 kg of the second-stage leaching solution was added for a second time at a liquid-solid ratio of 3.5:1 and continued to stir and react for 1.1 hours; water was used for the first slurrying, and the second-stage leaching solution was used for subsequent slurrying;

[0075] The final copper leaching rate is 85%, and a sponge copper with a grade of 98.15% can be obtained; the nickel leaching rate is 83.33%, and a nickel hydroxide grade of 21.92% can be obtained.

[0076] In summary, according to Example 1 and Comparative Examples 1-2, it can be seen that the stirred mill activation can activate the encapsulated oxidized copper and nickel that are difficult to leach in the first leachate, and significantly improve the copper and nickel leaching rate; and the copper and nickel leaching rate improvement effect of the stirred mill activation before the first stage of maturation leaching is not obvious. According to Example 1 and Comparative Example 3, it can be seen that the maturation temperature is too low to achieve efficient leaching of nickel and copper in the difficult-to-leach ore phase, thereby reducing the leaching rate.

[0077] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for extracting nickel and copper from nickel-copper oxide ore, characterized in that: The following steps are involved: S1, primary leaching: adding water or the second-stage leaching solution to the nickel copper oxide ore powder for slurrying, adding concentrated sulfuric acid for aging reaction, and adding the second-stage leaching solution again for primary leaching reaction to form a primary leaching slurry; Water is used for the first beating, and the second-stage leachate is used for subsequent beating; S2, second stage leaching: the first stage leaching slurry is thickened to obtain a thick supernatant and a thick underflow; the thick underflow is activated by a stirring mill, and then concentrated sulfuric acid is added to carry out a second stage leaching reaction, and then thickened and filtered to obtain a second stage leaching liquid and a leaching residue; S3, replacing copper: adding metallic iron to the concentrated supernatant of step S2 to carry out a replacement reaction to obtain a replaced liquid and sponge copper; S4, jet iron removal: adding a neutralizing agent to the replaced liquid in step S3 to perform jet oxidation iron removal, and filtering to obtain iron removal liquid and iron removal slag; S5, nickel precipitation: adding alkaline solution to the iron removal solution in step S4 for precipitation, filtering to obtain a nickel hydroxide product and a nickel precipitation solution.

2. The method according to claim 1, characterized in that In step S1, the method for preparing the nickel copper oxide ore powder comprises: dry grinding the nickel copper oxide ore to obtain the nickel copper oxide ore powder; the nickel copper oxide ore powder has a fineness of 180-210 mesh accounting for more than 80wt.%.

3. The method according to claim 1, characterized in that In step S1, the mass ratio of the second-stage leaching solution to the nickel copper oxide powder is 0.2-0.8:1; the mass ratio of the concentrated sulfuric acid to the nickel copper oxide powder is 0.3-0.5:1; the mass ratio of the second-stage leaching solution added again to the nickel copper oxide powder is 3-4:1; the temperature of the first-stage leaching reaction is 60-80°C, and the time is 1-2h.

4. The method according to claim 1, characterized in that: In step S1, the aging reaction temperature is 110-120° C. and the time is 0.5-1.5 h.

5. The method according to claim 1, characterized in that: In step S2, the stirring mill activation time is 0.3 to 1 hour.

6. The method according to claim 1, characterized in that In step S2, the volume ratio of the dense underflow to concentrated sulfuric acid is 0.05-0.2:1; the temperature of the second-stage leaching reaction is 60-80°C, and the time is 1-2 hours.

7. The method according to claim 1, characterized in that In step S3, the mass ratio of the metallic iron to the copper in the concentrated supernatant is 1-1.5:0.8-1.0; and the replacement reaction time is 0.6 to 1 h.

8. The method according to claim 1, characterized in that In step S4, the neutralizing agent includes any one of lime powder and slaked lime.

9. The method according to claim 1, characterized in that: In step S4, the jet oxidation deironing is carried out in air; the temperature of the jet oxidation deironing is 75-90° C., and the time is 4-5.5 hours.

10. The method according to claim 1, characterized in that In step S5, the alkaline solution includes a sodium hydroxide solution.

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