Neutralizing treatment method for wet smelting of low-grade copper oxide ore

Abstract

The invention relates to a low-grade copper oxide ore wet smelting neutralizing treatment method which comprises the following steps: step 1, carrying out crushing and ore grinding treatment on low-grade copper oxide ore, proportioning, and then carrying out magnetic separation operation on the low-grade copper oxide ore to obtain high-grade enriched copper ore and magnetic separation tailings; 2, water is added into the enriched copper ore obtained in the step 1 to adjust the enriched copper ore into homogeneous ore pulp, concentrated sulfuric acid is added for acid leaching, solid-liquid separation is carried out on leaching reaction materials, copper-containing leaching pregnant solution and leaching residues are obtained, 3, the leaching residues obtained in the step 2 are washed, underflow obtained after solid-liquid separation is washed is dehydrated, dehydrated leaching residues are obtained, and the copper-containing leaching pregnant solution is obtained. And 4, the magnetic separation tailings obtained in the step 1 and the dehydrated leaching residues obtained in the step 3 are mixed, alkaline auxiliary materials are added for neutralization, and neutralized waste residues are obtained. According to the technological process, the three technical problems of large leaching residue amount, high neutralization cost and low copper recovery rate in wet smelting of the low-grade copper oxide ore are solved at the same time.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology for copper ore, specifically to a method for neutralizing and treating low-grade oxidized copper ore during hydrometallurgical processes. Background Technology

[0002] In the hydrometallurgical process of copper ore, neutralization treatment is required to ensure that the discharged waste meets environmental standards. Currently, the hydrometallurgical copper smelting process, centered on leaching-extraction-electrowinning, has been widely applied globally. However, this process still faces significant challenges in industrial practice, mainly in two aspects: First, the currently exploitable copper oxide ores generally have low grades, resulting in excessive acid consumption and poor copper leaching recovery rates; second, when treating leaching residue, neutralization often uses a single alkaline auxiliary material, leading to a large consumption of alkaline auxiliary materials and resource waste. Therefore, we propose a method for neutralization and treatment of low-grade copper oxide ores during hydrometallurgical processes. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method for neutralizing and treating low-grade copper oxide ore during hydrometallurgical processes.

[0004] This invention is implemented by including the following steps: Step 1: Magnetic separation of raw ore: Low-grade copper oxide ore is crushed and ground, then batched and subjected to magnetic separation to obtain higher-grade enriched copper ore and magnetic tailings. Step 2: Leaching of enriched copper ore: The enriched copper ore obtained in Step 1 is adjusted with water to form a homogeneous slurry with a mass concentration of 25%, and then acidic leaching is carried out with sulfuric acid of a mass concentration of 98% to obtain leaching reaction material. The leaching reaction material is then subjected to solid-liquid separation to obtain copper-containing leaching solution and leaching residue. Step 3: Dewatering and washing of leaching residue: The leaching residue obtained in step 2 is washed in stages 1-3. The underflow after solid-liquid separation is dewatered to obtain dewatered leaching residue. Step 4: Neutralization of magnetic separation tailings: Mix the magnetic separation tailings obtained in Step 1 with the dewatered leaching residue obtained in Step 3, add alkaline auxiliary materials for neutralization, and obtain neutralized waste residue. After meeting environmental protection requirements, it is discharged into the environmental protection waste storage.

[0005] Preferably, in step 1, the copper grade of the copper oxide ore is 0.5%-2%, and the particle size of the raw material after grinding is -74μm or more, accounting for more than 70%.

[0006] Preferably, in step 1, the magnetic field strength of the magnetic separation is 1.2-1.7T, and the pulsation frequency is 100-200 times / min.

[0007] Preferably, in step 1, the copper grade in the enriched copper ore obtained by magnetic separation is 2-3 times that of the original ore, and the tailings from magnetic separation account for 1 / 2-2 / 3 of the raw ore.

[0008] Preferably, in step 2, when acid leaching the slurry with sulfuric acid, the leaching conditions are pH 1.5-2.0, acid consumption t(H2SO4) / t(Cu) 2.0-3.0, and leaching time 4-6h.

[0009] Preferably, in step 2, the copper leaching rate during acid leaching is >95%, the copper content in the leaching residue is <0.3%, and the water content in the leaching residue is 45%-55%.

[0010] Preferably, in step 3, the moisture content of the dehydrated leaching residue is 15%-25%.

[0011] Preferably, in step 4, the alkaline auxiliary material used to neutralize the dehydrated leaching residue is one or more of quicklime, limestone, or sodium carbonate.

[0012] Preferably, in step 4, the pH of the neutralized waste residue is 6.0-7.0.

[0013] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention adopts a combined hydrometallurgical process for low-grade oxidized copper ore, consisting of "magnetic separation-leaching-magnetic tailings neutralization". In the magnetic separation stage, pre-selection and waste disposal are performed on the raw ore to obtain high-grade enriched copper ore for leaching. This stage effectively separates and removes a large amount of tailings, significantly reducing the amount of ore entering the subsequent leaching process, thereby reducing the amount of leaching residue generated at the source. Subsequently, acid leaching is performed on the high-grade enriched copper ore, achieving a high copper recovery rate under conditions of low acid consumption. Finally, the tailings generated during magnetic separation are used as a neutralizing agent and recycled for the neutralization treatment of the leaching residue, effectively reducing the amount of additional neutralization auxiliary materials used and further reducing neutralization disposal costs. This process simultaneously solves the three major technical problems existing in the hydrometallurgical smelting of low-grade oxidized copper ore: large leaching residue volume, high neutralization cost, and low copper recovery rate, and has significant economic and environmental benefits. Attached Figure Description

[0014] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0015] The present invention will be further explained below with reference to specific implementation schemes, but this is not intended to limit the scope of protection of the present invention.

[0016] Example 1 A method for neutralizing and treating low-grade copper oxide ore during hydrometallurgical processes, comprising the following steps: Step 1: Magnetic separation of raw ore: The copper oxide ore with a copper grade of 0.73% is crushed and ground, and then batched. After grinding, the weight of the raw material with a particle size of -74μm accounts for more than 70% of the total weight. Magnetic separation is carried out under the conditions of magnetic field strength of 1.2T and pulse frequency of 150 times / min to obtain high-grade enriched copper ore with a copper grade of 1.95% and magnetic separation tailings, with a tailings rejection rate of 65%.

[0017] Step 2: Leaching of enriched copper ore: The high-grade enriched copper ore obtained in Step 1 is adjusted with water to form a homogeneous slurry with a mass concentration of 25%. 98% sulfuric acid is then added for acid leaching to obtain the leaching reaction material. The leaching conditions are: pH 1.8, acid consumption t(H₂SO₄) / t(Cu) 3.0, and leaching time 6 h. The leaching reaction material is then subjected to solid-liquid separation to obtain a copper-containing leaching solution and leaching residue. The copper leaching rate is 96%, the leaching residue contains 0.078% copper, and the leaching residue has a water content of 50%. Step 3: Dewatering and washing of leaching residue: The leaching residue obtained in step 2 is subjected to three-stage washing. The underflow after solid-liquid separation is dewatered to obtain dewatered leaching residue with a water content of 15%. Step 4: Neutralization of magnetic separation tailings: Mix the magnetic separation tailings obtained in Step 1 with the dewatered leaching residue obtained in Step 3, add quicklime for neutralization, and obtain neutralized waste residue with pH 6.5. After meeting environmental protection requirements, it is discharged into the environmental slag storage.

[0018] Example 2 A method for neutralizing and treating low-grade copper oxide ore during hydrometallurgical processes, comprising the following steps: Step 1: Magnetic separation of raw ore: The copper oxide ore with a copper grade of 1.21% is crushed and ground, and then batched. After grinding, the weight of the raw material with a particle size of -74μm accounts for more than 70% of the total weight. Magnetic separation is carried out under the conditions of magnetic field strength of 1.5T and pulse frequency of 100 times / min to obtain high-grade enriched copper ore with a copper grade of 2.59% and magnetic separation tailings, with a tailings rejection rate of 60%.

[0019] Step 2: Leaching of enriched copper ore. The high-grade enriched copper ore obtained in Step 1 is adjusted with water to form a homogeneous slurry with a mass concentration of 25%. Concentrated sulfuric acid with a mass concentration of 98% is added for acid leaching to obtain the leaching reaction material. The leaching conditions are: pH 1.5, acid consumption t(H2SO4) / t(Cu) 2.0, and leaching time 4 h. The leaching reaction material is then subjected to solid-liquid separation to obtain a copper-containing leaching solution and leaching residue. The copper leaching rate is 98%, the leaching residue contains 0.104% copper, and the leaching residue has a water content of 45%. Step 3: Dewatering and washing of leaching residue: The leaching residue obtained in step 2 is subjected to three-stage washing. The underflow after solid-liquid separation is dewatered to obtain dewatered leaching residue with a water content of 18%. Step 4: Neutralization of magnetic separation tailings: Mix the magnetic separation tailings obtained in Step 1 with the dewatered leaching residue obtained in Step 3, add quicklime for neutralization, and obtain neutralized waste residue with pH 7.0. After meeting environmental protection requirements, it is discharged into the environmental protection waste storage.

[0020] Example 3 A method for neutralizing and treating low-grade copper oxide ore during hydrometallurgical processes, comprising the following steps: Step 1: Magnetic separation of raw ore: The copper oxide ore with a copper grade of 1.87% is crushed and ground, and then batched. After grinding, the weight of the raw material with a particle size of -74μm accounts for more than 70% of the total weight. Magnetic separation is carried out under the conditions of magnetic field strength of 1.7T and pulse frequency of 200 times / min to obtain high-grade enriched copper ore with a copper grade of 4.11% and magnetic separation tailings, with a tailings rejection rate of 56%.

[0021] Step 2: Leaching of enriched copper ore. The high-grade enriched copper ore obtained in Step 1 is adjusted with water to form a homogeneous slurry with a mass concentration of 25%. Concentrated sulfuric acid with a mass concentration of 98% is added for acid leaching to obtain the leaching reaction material. The leaching conditions are: pH 2.0, acid consumption t(H2SO4) / t(Cu) 1.5, and leaching time 5 h. The leaching reaction material is then subjected to solid-liquid separation to obtain a copper-containing leaching solution and leaching residue. The copper leaching rate is 97%, the leaching residue contains 0.123% copper, and the leaching residue has a water content of 55%. Step 3: Dewatering and washing of leaching residue: The leaching residue obtained in step 2 is subjected to primary washing. The underflow after solid-liquid separation is dewatered to obtain dewatered leaching residue with a water content of 25%. Step 4: Neutralization of magnetic separation tailings: Mix the magnetic separation tailings obtained in Step 1 with the dewatered leaching residue obtained in Step 3, add quicklime for neutralization, and obtain neutralized waste residue with pH 6.0. After meeting environmental protection requirements, it is discharged into the environmental slag storage.

[0022] Example 4 A method for neutralizing and treating low-grade copper oxide ore through hydrometallurgical processes differs from the technical solution in Example 1 in that it directly employs an acid leaching process on the raw copper oxide ore. The acid consumption (t(H₂SO₄) / t(Cu)) is 3.8, the copper leaching rate is 87%, and the quicklime consumption is 4.3 times that of the method in Example 1. This demonstrates that compared to direct leaching of low-grade copper oxide ore, leaching of high-grade ore after magnetic separation can reduce acid consumption and improve copper recovery rate.

[0023] Example 5 A method for neutralizing and treating low-grade copper oxide ore by hydrometallurgical processes differs from the technical solution in Example 2 in that the magnetic separation tailings obtained in step 1 are not used in the neutralization process but are directly discharged to the tailings pond. Quicklime is added for neutralization. After neutralization treatment with the same amount of limestone as in Example 2, tailings with a pH of 5.2 are obtained. Thus, it can be seen that magnetic separation tailings can be used as a neutralizing agent for leaching residue.

[0024] Example 6 A method for neutralizing and treating low-grade copper oxide ore through hydrometallurgical processes differs from the technical solution in Example 3 in that the magnetic separation tailings obtained in step 1 are not used in the neutralization process but are directly discharged into the tailings pond. Quicklime is added for neutralization, and the leaching residue is neutralized to a pH of 6.0, consistent with that in Example 3. The amount of limestone consumed is 2.5 times that in Example 3. Therefore, it can be seen that when magnetic separation tailings are used as a neutralizing agent for leaching residue, the consumption of neutralization auxiliary materials can be reduced.

Claims

1. A method for neutralizing and treating low-grade copper oxide ore during hydrometallurgical processes, characterized in that, Includes the following steps: Step 1: Magnetic separation of raw ore: Low-grade copper oxide ore is crushed and ground, then batched and subjected to magnetic separation to obtain higher-grade enriched copper ore and magnetic tailings. Step 2: Leaching of enriched copper ore: The enriched copper ore obtained in Step 1 is adjusted with water to form a homogeneous slurry with a mass concentration of 25%, and then acidic leaching is carried out with sulfuric acid of a mass concentration of 98% to obtain leaching reaction material. The leaching reaction material is then subjected to solid-liquid separation to obtain copper-containing leaching solution and leaching residue. Step 3: Dewatering and washing of leaching residue: The leaching residue obtained in step 2 is washed in stages 1-3. The underflow after solid-liquid separation is dewatered to obtain dewatered leaching residue. Step 4: Neutralization of magnetic separation tailings: Mix the magnetic separation tailings obtained in Step 1 with the dewatered leaching residue obtained in Step 3, add alkaline auxiliary materials for neutralization, and obtain neutralized waste residue. After meeting environmental protection requirements, it is discharged into the environmental protection waste storage.

2. The method for neutralizing and treating low-grade oxidized copper ore during hydrometallurgical processing according to claim 1, characterized in that: In step 1, the copper grade of the copper oxide ore is 0.5%-2%, and the particle size of the raw material after grinding is more than 70% -74μm.

3. The method for neutralizing and treating low-grade copper oxide ore during hydrometallurgical processing according to claim 1, characterized in that: In step 1, the magnetic field strength of the magnetic separation is 1.2-1.7T, and the pulse frequency is 100-200 times / min.

4. The method for neutralizing and treating low-grade oxidized copper ore during hydrometallurgical processing according to claim 1, characterized in that: In step 1, the copper grade in the enriched copper ore obtained by magnetic separation is 2-3 times that of the original ore, and the tailings from magnetic separation account for 1 / 2-2 / 3 of the raw ore.

5. The method for neutralizing and treating low-grade oxidized copper ore during hydrometallurgical processing according to claim 1, characterized in that: In step 2, when acid leaching the slurry with sulfuric acid, the leaching conditions are pH 1.5-2.0, acid consumption t(H2SO4) / t(Cu) 2.0-3.0, and leaching time 4-6h.

6. The method for neutralizing and treating low-grade oxidized copper ore during hydrometallurgical processing according to claim 1, characterized in that: In step 2, the copper leaching rate during acid leaching is >95%, the copper content in the leaching residue is <0.3%, and the water content in the leaching residue is 45%-55%.

7. The method for neutralizing and treating low-grade copper oxide ore during hydrometallurgical processing according to claim 1, characterized in that: In step 3, the moisture content of the dehydrated leaching residue is 15%-25%.

8. The method for neutralizing and treating low-grade oxidized copper ore during hydrometallurgical processing according to claim 1, characterized in that: In step 4, the alkaline auxiliary material used to neutralize the dehydrated leaching residue is one or more of quicklime, limestone, or sodium carbonate.

9. The method for neutralizing and treating low-grade copper oxide ore during hydrometallurgical processing according to claim 1, characterized in that: In step 4, the pH of the neutralized waste residue obtained is 6.0-7.0.

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