Method for reducing silicon content in copper cobalt oxide ore leaching solution

Abstract

The invention belongs to the technical field of hydrometallurgy, and particularly relates to a method for reducing silicon content in copper cobalt oxide ore leachate, and the specific technical scheme is as follows: adding cobalt precipitation post-liquid into a last-stage leaching tank of a copper cobalt oxide ore agitation leaching process, and uniformly mixing the cobalt precipitation post-liquid with leached ore pulp; adding a coagulant into the leached ore pulp to form silica gel particles in the leached ore pulp; adding a flocculating agent into the leached ore pulp; finally, leached ore pulp enters a leaching thickener to be subjected to dense separation, and overflow leached liquid and underflow leached slag pulp are obtained; the overflow leaching liquid serves as high-copper feed liquid to enter a high-copper extraction procedure; and after underflow leaching slag slurry is subjected to CCD countercurrent washing, low-copper feed liquid is produced and enters a low-copper extraction procedure. According to the method, the cobalt precipitation post-liquid wastewater produced by a copper-cobalt hydrometallurgy plant is used as a medicament source of calcium and magnesium ions required by a coagulation reaction, and silicon is removed by a method of firstly adding a coagulant and then adding a flocculating agent in a strongly acidic ore pulp environment, so that the production requirements of a subsequent extraction process can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a method for reducing silicon content in a copper-cobalt oxide ore leaching solution. Background Art

[0002] Most of the copper-cobalt oxide ores in a certain area contain acid-soluble silicon. During the acid leaching process of the ore, silicon enters the solution along with copper-cobalt metal ions. The silicon content in the leachate can reach 200-1000 mg / L, which increases the viscosity of the leachate. When the silicon content of the leachate is higher than 100 mg / L, it is not conducive to the separation of the aqueous phase and the organic phase after entering the extraction process, especially bringing great difficulties to the regulation and control of the phase continuity state of the extraction mixing chamber. In the extraction process, when the aqueous phase outlet level of the raffinate or copper-rich liquid is aqueous phase continuous, the entrainment of the organic phase can be reduced. However, due to the high silicon content in the leachate, its viscosity increases, and when the aqueous phase is continuous, it is not conducive to the separation of the organic phase from the aqueous phase, resulting in a prolonged phase separation time and more organic phase entrainment in the aqueous phase. Therefore, most of the aqueous phase outlet levels of the extraction process of the hydrometallurgical smelter of copper-cobalt oxide ores in a certain area have to be produced in an organic phase continuous manner.

[0003] Silicon exists in the solution in the form of molecular, ionic and colloidal silica. Existing methods for removing silica from solutions, such as the patent "A method for removing silica from manganese sulfate solution" (patent application number: 202111428199.4) and the patent "A method for deep silicon removal from nickel-cobalt leaching solution" (patent application number: 202011094666.X), etc., mostly adjust the pH value of the solution to weak acidity or alkalinity, and then add a silicon removal agent to remove silica and separate the solid and liquid to obtain a desiliconized liquid and silicon-containing slag. This is because silicate is unstable in alkaline solutions and is prone to intramolecular polymerization to form polysilicic acid, which further forms silicate precipitates with metal cations to achieve the purpose of silicon removal.

[0004] The above method is not applicable to acidic solutions. Currently, there are few studies and reports on direct silicon removal methods for acidic solutions. Existing methods for direct silicon removal from acidic solutions, such as the patent "A method for removing silicon from acidic solutions" (patent application number: 202110378310.7), the patent "A method for purifying and removing silicon from nickel-cobalt solutions" (patent application number: 202011078830.8), etc., mostly add reagents such as γ-A12O3 and zirconium hydroxide to the acidic solution to adsorb and remove silicon in the solution, and then recover and regenerate the reagents after adsorbing silicon for recycling.

[0005] After the oxidized copper-cobalt ore is acid leached (leaching pH is 1.5-2.0), the leached pulp is first subjected to leaching concentration for solid-liquid separation to produce overflow high-copper-cobalt content liquid and bottom-flow leaching slag pulp. The bottom-flow leaching slag pulp is then subjected to CCD countercurrent washing to produce overflow low-copper-cobalt content liquid and bottom-flow tailings pulp. The tailings are discharged into the acid tailings pond, and the high-copper-cobalt content liquid and the low-copper-cobalt content liquid enter the extraction process. For the oxidized copper-cobalt ore leachate, it is impossible to increase the pH value and add a silicon remover, because it will cause the neutralization and precipitation of copper and cobalt metal ions and affect the production of subsequent extraction processes; at the same time, it is also impossible to use the method of directly adding a silicon adsorbent, because the silicon adsorbent will mix with the leaching slurry and cannot be separated and discharged into the tailings pond, resulting in silicon adsorbent consumption and loss, and silicon adsorbents are often expensive. Summary of the invention

[0006] The purpose of the present invention is to provide a method for reducing the silicon content in the leaching solution of copper-cobalt oxide ore to solve the problems raised by the background technology.

[0007] The above technical objectives of the present invention are achieved through the following technical solutions:

[0008] The present invention provides a method for reducing the silicon content in a copper-cobalt oxide ore leachate, comprising the following steps:

[0009] Step S1, adding the cobalt precipitation solution: adding the cobalt precipitation solution to the final leaching tank of the copper-cobalt oxide ore stirring leaching process, and mixing it evenly with the leaching slurry;

[0010] Step S2, adding a coagulant: adding a coagulant to the leached slurry to form silica gel particles in the leached slurry;

[0011] Step S3, adding flocculant: adding flocculant to the leached slurry

[0012] Step S4, thickening separation: the leached slurry is fed into a leaching thickener for thickening separation to obtain overflow leachate and underflow leachate slurry; the overflow leachate is used as a high-copper feed liquid and enters the high-copper extraction process; the underflow leachate slurry is subjected to CCD countercurrent washing to produce a low-copper feed liquid and enters the low-copper extraction process.

[0013] Furthermore, the cobalt precipitation liquid in step S1 is the low-copper raffinate obtained by copper-cobalt hydrometallurgy, which is the waste liquid produced after the steps of iron removal with lime and cobalt precipitation with magnesium oxide.

[0014] Furthermore, in step S2, a coagulant is added to the leached slurry to form silica gel particles in the mixed solution, including: overflowing the leached slurry from the final leaching tank to the transfer pump pool, and adding a coagulant to the transfer pump pool.

[0015] Furthermore, in step S3, flocculants are added to the leached slurry, including: adding flocculants to the external mixing tank and the central feed pipe of the leaching thickener step by step and mixing them with the leached slurry uniformly.

[0016] Furthermore, in the cobalt precipitation solution of step S1, the magnesium ion content is 5-15 g / L, and the calcium ion content is 100-500 mg / L.

[0017] Furthermore, after the cobalt precipitation liquid in step S1 is added to the leaching pulp, the total content of calcium and magnesium ions is 0.1 to 2.0 times the silicon content in the leaching pulp.

[0018] Furthermore, the amount of the coagulant added in step S2 is 0.001% to 0.01% of the dry ore weight in the leached slurry.

[0019] Furthermore, the flocculant is one or more of polyethyleneimine, polyacrylamide, sodium polyacrylate, polyaluminum chloride, polyferric sulfate, ferric chloride, aluminum sulfate, sodium dodecyl sulfate, polyferric phosphorus chloride or wood sulfonate.

[0020] Furthermore, the amount of the flocculant added is 0.005% to 0.01% of the dry ore weight in the leached slurry.

[0021] In summary, the present invention has the following beneficial effects:

[0022] By the method provided by the present invention, the wastewater after cobalt precipitation produced by the copper-cobalt hydrometallurgical plant is used as the reagent source of calcium and magnesium ions required for the coagulation reaction. In a strongly acidic ore pulp environment, silicon is removed by first adding a new coagulant and then adding a flocculant. The silicon removal rate in the final leaching solution is 85% to 95%, and the silicon content is 20 to 50 mg / L, which can meet the production requirements of the subsequent extraction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention provides a schematic process flow diagram of a method for reducing silicon content in a copper-cobalt oxide ore leachate. DETAILED DESCRIPTION

[0024] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, a method for reducing the silicon content in the leaching solution of copper-cobalt oxide ore proposed by the present invention, its specific implementation method, characteristics and effects are described in detail as follows.

[0025] The present specific embodiment provides a method for reducing the silicon content in a copper-cobalt oxide ore leachate, comprising the following steps:

[0026] S1, adding the cobalt precipitation liquid into the final leaching tank of the copper-cobalt oxide ore stirring leaching process and mixing evenly;

[0027] S2, adding a coagulant to the leached slurry to form silica gel particles in the leached slurry;

[0028] S3, adding flocculant to the leached slurry;

[0029] S4, the leached slurry enters the leaching thickener for thickening and separation to obtain overflow leaching liquid and underflow leaching slurry;

[0030] S5, the overflow leaching solution enters the high copper extraction process as the high copper feed solution;

[0031] S6. The bottom flow leaching slurry is washed by CCD countercurrent to produce low copper liquid which enters the low copper extraction process.

[0032] It can be understood that the method provided in this specific embodiment promotes the formation and separation of silica gel particles by introducing cobalt precipitation liquid, coagulant and flocculant into the copper-cobalt oxide ore leachate, thereby effectively reducing the silicon content in the solution and ensuring the phase continuity and stability of the subsequent extraction process.

[0033] In some preferred embodiments, the cobalt precipitation liquid is a low-copper raffinate obtained from copper-cobalt hydrometallurgy, which is a waste liquid produced after the steps of iron removal by lime and cobalt precipitation by magnesium oxide.

[0034] It is understandable that the waste liquid provided by this specific embodiment has certain chemical activity, and contains relatively high calcium and magnesium ions, and the calcium and magnesium ions in the solution can promote the polymerization of silicic acid and colloidal silica, which can enhance the sedimentation effect of silica gel particles in the leachate, further reduce the silicon content, improve the liquid-solid separation efficiency, and provide a purer feed liquid for subsequent high-copper and low-copper extraction processes. In addition, this method improves the separation and recovery efficiency of copper and cobalt by strengthening the purification effect of the leachate, optimizes the process flow, and improves the overall economy and environmental friendliness.

[0035] In some preferred embodiments, a coagulant is added to the leached slurry to form silica gel particles in the leached slurry, comprising:

[0036] The leached slurry overflows from the final leaching tank to the transfer pump pool, and coagulant is added to the transfer pump pool.

[0037] It can be understood that the coagulant is added to the transfer pump pool so that the leached slurry is evenly mixed with the coagulant before entering the leaching thickener, and a coagulation reaction occurs during the pipeline transportation process, at which time the silica gel in the solution becomes unstable and polymerizes to form silica gel particles.

[0038] In some preferred embodiments, adding a flocculant to the leached slurry comprises: adding the flocculant to the external mixing tank and the central feed pipe of the leaching thickener step by step and mixing the mixed liquid uniformly.

[0039] It can be understood that flocculants are added to the external mixing tank and the central feed pipe of the leaching thickener step by step and mixed evenly with the leaching slurry, so that the silica gel particles formed by the instability and polymerization of silica gel in the slurry undergo flocculation and bridging reactions, and further agglomerate into larger particles and settle.

[0040] In some preferred embodiments, the magnesium ion content in the solution after cobalt precipitation is 5-15 g / L, and the calcium ion content is 100-500 mg / L.

[0041] In some preferred embodiments, after the cobalt precipitation solution is added to the leaching pulp, the total content of calcium and magnesium ions is 0.1 to 2.0 times the silicon content in the leaching pulp.

[0042] It is understandable that if the total content of calcium and magnesium ions in the liquid after cobalt precipitation is lower than 0.1 times the silicon content in the leaching slurry, it may lead to insufficient formation of silica gel particles, making it impossible for silicon to effectively precipitate in the solution, reducing the liquid-solid separation efficiency, and thus causing the silicon content in the solution to be too high, affecting the efficiency of subsequent extraction processes and even reducing the recovery rate of copper and cobalt.

[0043] If the total content of calcium and magnesium ions exceeds 2.0 times the silicon content, it may generate unnecessary by-products (such as gypsum), which will have a negative impact on the purity of the liquid and the operation of the equipment, and will also increase the cost of raw materials and waste liquid treatment. Therefore, only by controlling the total content of calcium and magnesium ions within the range of 0.1 to 2.0 times the silicon content can silicon be effectively removed and good liquid purity and equipment operation be maintained.

[0044] In some preferred embodiments, the amount of coagulant added is 0.001% to 0.01% of the dry ore weight in the leached slurry.

[0045] In some preferred embodiments, the flocculant is one or more of polyethyleneimine, polyacrylamide, sodium polyacrylate, polyaluminum chloride, polyferric sulfate, ferric chloride, aluminum sulfate, sodium dodecyl sulfate, polyferric phosphorus chloride or wood sulfonate.

[0046] In some preferred embodiments, the amount of flocculant added is 0.005% to 0.01% of the dry ore weight in the leached slurry.

[0047] In some preferred embodiments, a method for reducing silicon content in a copper-cobalt oxide ore leachate comprises the following steps:

[0048] S 1. Add the cobalt precipitation liquid: The cobalt precipitation liquid is the waste liquid produced by the processes of lime iron removal and magnesium oxide cobalt precipitation of the low copper raffinate of the copper-cobalt hydrometallurgical plant. It contains high calcium and magnesium ions, and the calcium and magnesium ions in the solution can promote the polymerization of silicic acid and colloidal silica. The cobalt precipitation liquid is added to the final leaching tank of the stirring leaching process of the copper-cobalt oxide ore, so that the calcium and magnesium ions in the cobalt precipitation liquid are evenly mixed with the leached ore pulp under the mechanical stirring of the final leaching tank.

[0049] S2. Adding coagulant: The leached slurry overflows from the final leaching tank to the transfer pump pool, and then is pumped to the leaching thickener for solid-liquid separation. Coagulant is added to the transfer pump pool so that the leached slurry is evenly mixed with the coagulant before entering the leaching thickener, and a coagulation reaction occurs during the pipeline transportation process. At this time, the silica gel in the solution is unstable and polymerized to form silica gel particles.

[0050] S3. Adding flocculant: Add flocculant step by step to the external mixing tank of the leaching thickener and the central feed pipe and mix them with the leaching slurry evenly, so that the silica gel particles formed by the instability and polymerization of silica gel in the slurry will undergo flocculation and bridging reaction, further agglomerate into larger particles and settle.

[0051] S4, thickening separation: the leached slurry enters the central cylinder of the leaching thickener, and after flocculation and sedimentation, overflow leaching liquid and underflow leaching slurry are obtained. The overflow leaching liquid enters the high-copper extraction process as the high-copper liquid, and the underflow leaching slurry is washed by CCD countercurrent to produce low-copper liquid and enter the low-copper extraction process.

[0052] It can be understood that the method provided in this specific embodiment achieves efficient reduction of silicon content in the leachate of copper-cobalt oxide ore through the synergistic effect of calcium and magnesium ions, coagulants and flocculants. Specifically, calcium and magnesium ions rich in the solution after cobalt precipitation react with silicic acid and colloidal silica in the final leaching tank of the leached slurry, promoting the polymerization of silicic acid and colloidal silica, causing them to become unstable and initially forming silica gel particles.

[0053] Next, a coagulant is added to the transfer pump pool to mix the coagulant and the leached slurry evenly and cause a coagulation reaction in the delivery pipeline. At this time, the silica gel in the solution is further destabilized and aggregates to form more silica gel particles, which improves the removal efficiency of silicon.

[0054] Subsequently, flocculants are added in stages to the external mixing tank and central feed pipe of the leaching thickener and mixed with the slurry. The flocculants further aggregate the silica gel particles to form larger flocs through bridging and agglomeration reactions, thereby significantly increasing the sedimentation rate of the particles. This multi-stage flocculation reaction not only accelerates the sedimentation of silica gel particles, but also ensures that the silicon content in the underflow leaching slurry is further reduced.

[0055] Finally, through the solid-liquid separation process in the leaching thickener, the silica gel particles settle with the underflow slurry, reducing the silicon content in the overflow leachate. The overflow liquid enters the high-copper extraction process as a high-copper solution, and the underflow slurry is washed by CCD to produce a low-copper solution and enter the low-copper extraction process, thereby achieving effective removal of silicon and ensuring the efficiency and stability of subsequent extraction processes. The compound use of calcium and magnesium ions, coagulants and flocculants complement each other, and through the action mechanism at different stages, the efficient removal of silicon in the leachate is successfully achieved.

[0056] The present invention is further described below in conjunction with specific embodiments. It should be pointed out that this embodiment is a small-scale experiment simulating a production process in a laboratory, and the focus is on demonstrating that the method of the present invention can effectively remove silicon. The stirring tank and thickener mentioned above are the implementation methods for carrying out the reaction in actual production, which is equivalent to the enlargement of the small-scale experiment.

[0057] Example 1

[0058] In this example, 1000 mL of leached pulp from a copper-cobalt oxide ore was taken into a beaker. The solid content of the leached pulp was 31%, and the ore density was 2.75 g / cm 3 The pH value of the slurry is 1.58, the silicon content in the slurry solution is 450 mg / L, and the magnesium ion content of the cobalt precipitation liquid produced by the cobalt precipitation workshop is 8.32 g / L and the calcium ion content is 158 mg / L.

[0059] S1. Add 42 mL of cobalt precipitation solution to the leached slurry, and stir and mix for 2 min to obtain a mixed solution;

[0060] S2, add 15.45 mg of coagulant to the mixed solution and stir for 2 minutes;

[0061] S3, add 23.17 mg of polyacrylamide to the beaker, stir and mix for 2 minutes, then stop stirring to obtain a slurry mixture;

[0062] S4. Settle the slurry mixture, and after the slurry solids have settled, take the supernatant for testing and analysis.

[0063] The analysis results show that the silicon content of the supernatant is 42 mg / L and the silicon removal rate is 90.67%.

[0064] Comparative Example 1

[0065] Take 1000mL of leaching pulp of a copper-cobalt oxide ore in a beaker. The solid content of the leaching pulp is 31% and the ore density is 2.75g / cm 3 , the pH value of the slurry is 1.58, and the silicon content in the slurry solution is 450 mg / L.

[0066] S1. Add 16.22 mg of coagulant to the leached slurry and stir for 2 min to obtain a mixed solution;

[0067] S2, adding 23.94 mg of polyacrylamide to the mixed solution, stirring for 2 minutes and then stopping stirring to obtain a slurry mixed solution;

[0068] S3, let the slurry mixture settle, and after the slurry solids settle, take the supernatant for detection and analysis.

[0069] The analysis results show that the silicon content of the supernatant is 105 mg / L and the silicon removal rate is 76.67%.

[0070] Comparative Example 2

[0071] Take 1000mL of leaching pulp of a copper-cobalt oxide ore in a beaker. The solid content of the leaching pulp is 31% and the ore density is 2.75g / cm 3 , the pH value of the slurry is 1.58, and the silicon content in the slurry solution is 450 mg / L.

[0072] S1. Add 25.96 mg of polyacrylamide to the leached slurry, stir and mix for 2 minutes, then stop stirring to obtain a slurry mixture;

[0073] S2. Settle the slurry mixture, and after the slurry solids have settled, take the supernatant for testing and analysis.

[0074] The analysis results show that the silicon content in the supernatant is 312 mg / L and the silicon removal rate is 30.67%.

[0075] Comparative Example 3

[0076] Take 1000mL of leaching pulp of a copper-cobalt oxide ore in a beaker. The solid content of the leaching pulp is 31% and the ore density is 2.75g / cm 3 , the pH value of the slurry is 1.58, and the silicon content in the slurry solution is 450 mg / L.

[0077] S1. Add 42 mL of cobalt precipitation solution to the leached slurry, and stir and mix for 2 min to obtain a mixed solution;

[0078] S2, add 15.45 mg of coagulant to the mixed solution and stir for 2 minutes;

[0079] S3, let the slurry mixture settle, and after the slurry solids settle, take the supernatant for detection and analysis.

[0080] The analysis results show that the silicon content of the supernatant is 136 mg / L and the silicon removal rate is 69.78%.

[0081] Comparative Example 4

[0082] Take 1000mL of leaching pulp of a copper-cobalt oxide ore in a beaker. The solid content of the leaching pulp is 31% and the ore density is 2.75g / cm 3 , the pH value of the slurry is 1.58, and the silicon content in the slurry solution is 450 mg / L.

[0083] S1. Add 42 mL of cobalt precipitation solution to the leached slurry, and stir and mix for 2 min to obtain a mixed solution;

[0084] S2. Add 23.17 mg of polyacrylamide to the beaker, stir for 2 minutes and then stop stirring to obtain a slurry mixture;

[0085] S3, let the slurry mixture settle, and after the slurry solids settle, take the supernatant for detection and analysis.

[0086] The analysis results show that the silicon content of the supernatant is 353 mg / L and the silicon removal rate is 21.56%.

[0087] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been presented as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A method for reducing silicon content in a copper-cobalt oxide ore leachate, characterized in that: The steps include: Step S1, adding the cobalt precipitation solution: adding the cobalt precipitation solution to the final leaching tank of the copper-cobalt oxide ore stirring leaching process, and mixing it evenly with the leaching slurry; Step S2, adding a coagulant: adding a coagulant to the leached slurry to form silica gel particles in the leached slurry; Step S3, adding flocculant: adding flocculant to the leached slurry Step S4, thickening separation: the leached slurry is fed into a leaching thickener for thickening separation to obtain overflow leachate and underflow leachate slurry; the overflow leachate is used as a high-copper feed liquid and enters the high-copper extraction process; the underflow leachate slurry is subjected to CCD countercurrent washing to produce a low-copper feed liquid and enters the low-copper extraction process.

2. The method for reducing silicon content in a copper-cobalt oxide ore leachate according to claim 1, characterized in that: The cobalt precipitation liquid in step S1 is the low-copper raffinate obtained by copper-cobalt hydrometallurgy, which is the waste liquid produced after the steps of iron removal by lime and cobalt precipitation by magnesium oxide.

3. The method for reducing silicon content in a copper-cobalt oxide ore leachate according to claim 1, characterized in that: In step S2, a coagulant is added to the leached slurry to form silica gel particles in the mixed solution, including: The leached slurry overflows from the final leaching tank to the transfer pump pool, and coagulant is added to the transfer pump pool.

4. The method for reducing silicon content in a copper-cobalt oxide ore leachate according to claim 1, characterized in that: In step S3, flocculants are added to the leached slurry, including: adding flocculants to the external mixing tank and the central feed pipe of the leaching thickener step by step and mixing them with the leached slurry evenly.

5. The method for reducing silicon content in a copper-cobalt oxide ore leachate according to claim 1, characterized in that: In the cobalt precipitation solution of step S1, the magnesium ion content is 5-15 g / L, and the calcium ion content is 100-500 mg / L.

6. The method for reducing silicon content in a copper-cobalt oxide ore leachate according to claim 1, characterized in that: After the cobalt precipitation solution in step S1 is added to the leaching pulp, the total content of calcium and magnesium ions is 0.1 to 2.0 times the silicon content in the leaching pulp.

7. The method for reducing silicon content in a copper-cobalt oxide ore leachate according to claim 1, characterized in that: The amount of the coagulant added in step S2 is 0.001% to 0.01% of the dry ore weight in the leached slurry.

8. The method for reducing silicon content in a copper-cobalt oxide ore leachate according to claim 1, characterized in that: The flocculant is one or more of polyethyleneimine, polyacrylamide, sodium polyacrylate, polyaluminium chloride, polyferric sulfate, ferric chloride, aluminium sulfate, sodium dodecyl sulfate, polyferric phosphorus chloride or wood sulfonate.

9. The method for reducing silicon content in a copper-cobalt oxide ore leachate according to claim 1, characterized in that: The added amount of the flocculant is n.005% to 0.01% of the dry ore weight in the leached slurry.

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