Process for extracting pure copper from copper oxide ore

Abstract

The invention relates to the technical field of mineral processing, and particularly discloses a process for extracting pure copper from copper oxide ore. According to the technology, the agitation leaching method is adopted, the polycarboxylate superplasticizer with lignin groups is added, agglomeration of the argillaceous minerals is hindered, the dispersion effect of the argillaceous minerals is improved, hindering of the argillaceous minerals on dissolution of copper is reduced, and therefore the high copper leaching rate is obtained with the argillaceous minerals as the raw material. According to the process disclosed by the invention, the extraction of copper can be thoroughly realized, so that the waste of copper resources is reduced, the production cost is favorably reduced, the copper content of wastes generated in the whole process is also reduced, and the pollution of the copper-containing wastes to the environment is favorably reduced.

Description

Technical Field

[0001] The present invention relates to the field of mineral processing technology, and more particularly, to a process for extracting and purifying copper from copper oxide ore. Background Art

[0002] Copper is a widely distributed metal with a range of excellent properties, making it a widely used metal. Pure copper is an excellent conductor of electricity, second only to silver but far exceeding that of other metals. The extraction and purification of copper resources has long been a key research area in the field of mineral processing. With the development of the global economy and technological advancements, the demand for copper, a key industrial raw material, continues to increase. In this context, improving copper extraction efficiency has significant economic and environmental implications.

[0003] Copper oxide ore is a significant component of my country's copper resources, with relatively abundant reserves. Most sulfide deposits in my country have an oxidation zone above them. Oxide copper ore generally exhibits low grade, high oxidation rate, high binding rate, and sludge formation, making it difficult to achieve satisfactory technical and economic performance using conventional metallurgical processes. Currently, heap leaching is the primary method for extracting copper from copper oxide ore.

[0004] Regarding the above-mentioned related technologies, the inventors believe that although the currently used methods can extract copper from copper oxide ores, for copper oxide ores accompanied by primary ore mud, mud minerals such as kaolin, talc, and goethite will hinder the dissolution of copper, resulting in a low final copper leaching rate, which not only causes a waste of copper ore resources but also increases the production cost of copper. Summary of the Invention

[0005] For copper oxide ores associated with primary ore slimes, the argillaceous minerals hinder copper dissolution during acid leaching, resulting in a low final copper leaching rate. This not only wastes copper resources but also increases copper production costs. To address this shortcoming, the present application provides a process for extracting and purifying copper from copper oxide ores.

[0006] The present application provides a process for extracting and purifying copper from copper oxide ore, which adopts the following technical solution: A process for extracting and purifying copper from copper oxide ore comprises the following steps: (1) Crushing the copper oxide ore, washing and classifying it to obtain lump ore and mud ore; (2) heap leaching the bulk ore to obtain a first leachate; mixing the muddy ore and the anti-clay composition and adding them to an acid leaching solution for stirring and leaching to obtain a second leachate; in this step, the anti-clay composition comprises a polycarboxylate water reducer having lignin groups grafted into its molecules, and the amount of the polycarboxylate water reducer is 0.3-0.6% of the total weight of the muddy ore; (3) extracting the mixture of the first leachate and the second leachate with an organic extractant, and then back-extracting the organic phase with sulfuric acid to obtain a copper-rich solution, and electrolytically processing the copper-rich solution to obtain a cathode copper product.

[0007] By adopting the above technical solution, the present application first preliminarily screened the copper oxide ore by crushing and washing classification to obtain bulk ore and muddy ore, and directly heap leached the bulk ore. For the muddy ore, the present application added a polycarboxylate water-reducing agent with a lignin group grafted into the molecule, and limited the amount of the polycarboxylate water-reducing agent. The polycarboxylate water-reducing agent itself has a certain steric hindrance effect, and the lignin group has a more complex spatial structure, which can make the steric hindrance effect of the polycarboxylate water-reducing agent more fully exerted. At the same time, lignin can also adjust the hydrophilic and hydrophobic properties of the polycarboxylate water-reducing agent, which is beneficial to the combination of the polycarboxylate water-reducing agent and the muddy mineral. The polycarboxylate water-reducing agent can be adsorbed with the mud minerals doped in the copper oxide ore. Under the action of steric hindrance, the polycarboxylate water-reducing agent can hinder the agglomeration of the mud minerals, improve the dispersion effect of the mud minerals, and reduce the obstruction caused by the mud minerals to the dissolution of copper. In addition, the stirring leaching method also helps to fully dissolve the copper. Therefore, the process of the present application can more thoroughly achieve the extraction of copper, reduce the waste of copper resources, and help reduce production costs. In addition, since the copper extraction is more thorough, the copper content of the waste generated in the entire process will also decrease, which helps to reduce the pollution caused by copper-containing waste to the environment.

[0008] Preferably, the polycarboxylate water reducer is prepared according to the following method: (1) adding an acrylic acid monomer and ascorbic acid to water and mixing to obtain liquid A; adding an initiator and mercaptoethanol to water and mixing to obtain liquid B; (2) Add unsaturated ester of lignin and alkenyl polyoxyethylene ether into water and mix, add sodium lauryl sulfate after heating, and then add solution A and solution B dropwise in sequence. After the addition is completed, continue to keep warm and react. After the reaction is completed, use sodium hydroxide to adjust the pH value. After the product is dialyzed and intercepted and rotary evaporated to obtain a polycarboxylic acid water reducer.

[0009] By adopting the above technical solution, the present application uses acrylic acid monomers, unsaturated esters of lignin, and alkenyl polyoxyethylene ether as main monomers, and carries out a polymerization reaction under the action of an initiator to obtain a polycarboxylic acid water reducer containing a lignin group.

[0010] Preferably, the unsaturated ester of lignin is prepared according to the following method: Alkali lignin is added to DMSO and dissolved to obtain a lignin solution; the lignin solution is placed in an ice-water bath in a nitrogen atmosphere, and then triethylamine and acryloyl chloride are added to the lignin solution in sequence. After heat preservation and reaction, the product is precipitated and separated using a saturated sodium bicarbonate solution, and then filtered and the filter cake is washed to obtain an unsaturated ester of lignin.

[0011] By adopting the above technical solution, the present invention first dissolves alkali lignin in DMSO, then reacts acryloyl chloride with the alkali lignin in the presence of an acid-binding agent, triethylamine, to obtain an unsaturated lignin ester with carbon-carbon double bonds. Subsequently, the unsaturated lignin ester is extracted by adding a saturated sodium bicarbonate solution for precipitation, washing, and drying.

[0012] Preferably, the weight of the unsaturated lignin ester is 1.5-3.5% of the weight of the alkenyl polyoxyethylene ether.

[0013] By adopting the above technical solution, the present application optimizes the dosage of the unsaturated ester of lignin, enhances the steric hindrance effect of the polycarboxylic acid water reducer, and helps to fully reduce the obstruction of the dissolution of copper caused by muddy minerals.

[0014] Preferably, the anti-clay composition further comprises sodium gluconate.

[0015] By adopting the above technical solution, sodium gluconate has a smaller molecule and has a similar adsorption mechanism to polycarboxylate water-reducing agent. Therefore, while sodium gluconate occupies a portion of the adsorption sites on the surface of the argillaceous mineral particles, it also reduces the excessive aggregation of the polycarboxylate water-reducing agent on the surface of the argillaceous mineral, improves the dispersion effect of the polycarboxylate water-reducing agent, and helps to fully reduce the obstruction of the argillaceous minerals to the dissolution of copper.

[0016] Preferably, the anti-clay composition further comprises sodium lignin sulfonate.

[0017] By adopting the above technical solution, sodium lignin sulfonate and the polycarboxylate water-reducing agent of the present application contain similar lignin groups, and there is a synergistic effect between the two, which helps to fully reduce the obstacles caused by muddy minerals to the dissolution of copper.

[0018] Preferably, the amount of sodium lignin sulfonate used is 3-5% by weight of the polycarboxylate water reducer.

[0019] By adopting the above technical solution, the present application optimizes the dosage of sodium lignin sulfonate, which helps to fully reduce the obstacles caused by muddy minerals to the dissolution of copper.

[0020] Preferably, in step (2) of the process, the sulfuric acid concentration of the pickling solution is 1.8-2.2 mol / L.

[0021] By adopting the above technical solution, the present application optimizes the sulfuric acid concentration of the acid leaching solution. With the assistance of the polycarboxylate water reducer, the acid leaching solution selected within this concentration range helps to fully achieve the leaching of copper.

[0022] Preferably, in step (2) of the process, the weight ratio of the acid leaching solution to the muddy ore is (3.5-4.2):1.

[0023] By adopting the above technical solution, the present application optimizes the weight ratio range of the acid leaching solution to the muddy ore. With the assistance of the polycarboxylate water reducer, the stirring leaching process implemented within this ratio range helps to fully achieve the leaching of copper.

[0024] Preferably, in step (2) of the process, the stirring rate during stirring and leaching is 240-320 r / min.

[0025] By adopting the above technical solution, the present application optimizes the stirring rate when stirring and leaching the muddy ore. The stirring and leaching process implemented within this range helps to fully achieve the leaching of copper.

[0026] In summary, this application has the following beneficial effects: 1. This application separately screens out the muddy ore from the copper oxide ore, then adds a polycarboxylate superplasticizer with lignin groups grafted into the molecule, and limits the amount of the polycarboxylate superplasticizer. The polycarboxylate superplasticizer can hinder the agglomeration of muddy minerals, improve the dispersion of muddy minerals, and reduce the obstruction caused by muddy minerals to the dissolution of copper. In addition, the stirring leaching method also facilitates the full dissolution of copper. Therefore, the process of this application can achieve more thorough copper extraction, reduce the waste of copper resources, and help reduce production costs.

[0027] 2. In the process of the present application, since copper is extracted more thoroughly, the copper content of the waste generated in the entire process will also decrease, which helps to reduce the pollution caused by copper-containing waste to the environment.

[0028] 3. The present application preferably uses sodium gluconate and sodium lignin sulfonate as components of the anti-clay composition. The two can fully reduce the obstruction of copper dissolution caused by muddy minerals through synergistic effect with the polycarboxylate water reducer. DETAILED DESCRIPTION

[0029] The present application is further described in detail below with reference to the Examples, Preparation Examples and Comparative Examples. The raw materials involved in the present application can all be obtained commercially.

[0030] Preparation example of polycarboxylate water reducer The following is an explanation using Preparation Example 1.

[0031] Preparation Example 1 The unsaturated ester of lignin used in this preparation example was prepared as follows: Alkali lignin, triethylamine, and acryloyl chloride were weighed in a weight ratio of 5:0.7:2.8, and the alkali lignin was added to DMSO and dissolved to obtain a lignin solution; the lignin solution was placed in an ice-water bath under a nitrogen atmosphere, and then triethylamine and acryloyl chloride were added to the lignin solution in sequence. After the reaction was kept at 40°C for 5 hours, the product was precipitated and separated using a saturated sodium bicarbonate solution, and then filtered and the filter cake was washed. After drying at 50°C to constant weight, an unsaturated ester of lignin was obtained.

[0032] In this preparation example, the acrylic acid monomer is acrylic acid, and the alkenyl polyoxyethylene ether is isopentenyl polyoxyethylene ether (M w =2400), the molar ratio of alkenyl polyoxyethylene ether to acrylic acid is 1:3.3, the weight of the unsaturated lignin ester is 1% of the weight of the alkenyl polyoxyethylene ether; the masses of sodium lauryl sulfate, initiator APS, ascorbic acid, and mercaptoethanol are 1%, 2%, 0.2%, and 0.5% of the total weight of the monomers (i.e., the total weight of the unsaturated lignin ester and acrylic acid), respectively.

[0033] In this preparation example, the polycarboxylate water-reducing agent was prepared according to the following method: (1) Adding acrylic acid monomer and ascorbic acid into water and mixing to obtain liquid A; adding initiator ASP and mercaptoethanol into water and mixing to obtain liquid B; In this step, acrylic acid monomer, (2) The unsaturated ester of lignin and isopentenyl polyoxyethylene ether were added to water and mixed, and then sodium lauryl sulfate was added after heating to 80°C, and then solution A and solution B were added dropwise in sequence. After the addition was completed, the reaction was continued by keeping warm for 1 hour. After the reaction was completed, the pH value was adjusted to 7.0 using 30wt% sodium hydroxide, and the product was dialyzed (with a molecular weight cutoff of 1000 and a dialysis cutoff time of one week) and rotary evaporation to obtain a polycarboxylic acid water reducer.

[0034] Preparation Example 2 The difference between this preparation example and preparation example 1 is that the weight of the unsaturated lignin ester is 1.5% of the weight of the alkenyl polyoxyethylene ether.

[0035] Preparation Example 3 The difference between this preparation example and preparation example 1 is that the weight of the unsaturated ester of lignin is 2.5% of the weight of the alkenyl polyoxyethylene ether.

[0036] Preparation Example 4 The difference between this preparation example and preparation example 1 is that the weight of the unsaturated lignin ester is 3.5% of the weight of the alkenyl polyoxyethylene ether.

[0037] Examples 1-5 The following description will be made using Example 1 as an example.

[0038] Example 1 The copper oxide ore used in this embodiment has a copper content of 1.46 wt %, an initial particle size distribution between 5.6 and 25 mm, and the weight of the lump ore accounts for 48.3% of the total weight of the copper oxide ore.

[0039] This embodiment provides a process for extracting and purifying copper from copper oxide ore, comprising the following steps: (1) crushing the copper oxide ore, washing and classifying it to obtain lump ore and mud ore; in this step, the particle size boundary between the lump ore and the mud ore is 0.074 μm; (2) According to 60L / m 2 h, spraying an acid leaching solution into the bulk ore, heap leaching the bulk ore for 60 days to obtain a first leachate; mixing the muddy ore and the anti-clay composition and adding them to the acid leaching solution, stirring and leaching at 60° C. for 3 hours to obtain a second leachate; in this step, the anti-clay composition includes a polycarboxylate water reducer, which is prepared according to the method of Preparation Example 1, and the amount of the polycarboxylate water reducer is 0.3% of the total weight of the muddy ore; the acid leaching solution is a sulfuric acid solution, the sulfuric acid concentration of the acid leaching solution is 1.5 mol / L, the weight ratio of the acid leaching solution to the muddy ore is 3.2:1, and the stirring rate during stirring leaching is 200 r / min; (3) The mixture of the first leachate and the second leachate was extracted with an organic extractant for 10 min, and then the organic phase was back-extracted with sulfuric acid at a concentration of 280 g / L to obtain a copper-rich solution. 2 The copper-rich solution was electrolytically processed at a current density of 1.0 h and a cell voltage of 2.1 V to obtain a cathode copper product; in this step, the organic extractant was LIX984N and kerosene (mixed in a volume ratio of 1:1).

[0040] As shown in Table 1, the main difference between Examples 1-5 is that the percentage of the amount of polycarboxylic acid water reducer to the total weight of the muddy ore (referred to as the water reducer ratio) is different.

[0041] Table 1 Water reducing agent proportion sample Example 1 Example 2 Example 3 Example 4 Example 5 Water reducing agent proportion / % 0.3 0.4 0.45 0.5 0.6 Example 6 The difference between this embodiment and embodiment 5 is that the anti-clay composition further includes sodium gluconate, and the weight ratio of sodium gluconate to polycarboxylate water reducer is 1:5.

[0042] Example 7 The difference between this embodiment and embodiment 6 is that the anti-clay composition further comprises sodium lignin sulfonate, and the amount of sodium lignin sulfonate used is 1.5% by weight of the polycarboxylate water-reducing agent.

[0043] As shown in Table 2, the difference between Examples 7-10 is that the percentage of sodium lignin sulfonate used in the weight of the polycarboxylate water-reducing agent is different (abbreviated as LS percentage).

[0044] Table 2 LS proportion sample LS proportion / % Example 7 1.5 Example 8 3 Example 9 4 Example 10 5 As shown in Table 3, the difference between Examples 10-13 is that the concentration of sulfuric acid in the acid leaching solution used in step (2) is different.

[0045] Table 3 Sulfuric acid concentration sample Sulfuric acid concentration / (mol / L) Example 10 1.5 Example 11 1.8 Example 12 2.0 Example 13 2.2 As shown in Table 4, the difference between Examples 13-16 is that the weight ratio of the acid leaching solution to the muddy ore (abbreviated as acid-ore ratio) used in step (2) is different.

[0046] Table 4 Acid-ore ratio sample Acid-ore ratio Example 13 3.2:1 Example 14 3.5:1 Example 15 3.9:1 Example 16 4.2:1 As shown in Table 5, the difference between Examples 16-19 is that in step (2), the stirring rates during stirring and leaching are different.

[0047] Table 5 Stirring rate sample Stirring speed / (r / min) Example 16 200 Example 17 240 Example 18 280 Example 19 320 Comparative Example Comparative Example 1 The difference between this comparative example and Example 1 is that no polycarboxylate water-reducing agent is added during the stirring leaching in step (2).

[0048] Comparative Example 2 The difference between this comparative example and Example 1 is that, during the stirring and leaching in step (2), the polycarboxylate water-reducing agent added does not contain lignin groups.

[0049] Comparative Example 3 The difference between this comparative example and Example 1 is that in step (2), the muddy ore and the polycarboxylate water reducer (prepared according to the method of Preparation Example 1) equivalent to 0.3% of the total weight of the muddy ore are mixed and piled into a pile, and then the mixture is heated at 75 L / m 2 The acid leaching solution was sprayed into the muddy ore at a spraying intensity of 1.5 h, and the lump ore was heap leached for 60 days to obtain the second leachate.

[0050] Performance testing methods The copper leaching rate was calculated based on the copper content of the second leachate and the total copper content in the muddy ore. Then, based on the leaching rate of Comparative Example 1, the ratio between the leaching rate of each embodiment and the comparative example and the leaching rate of Comparative Example 1 was calculated. The ratio was recorded as the relative leaching rate. The results are shown in Table 6.

[0051] Table 6 Relative leaching rate Combining Examples 1-5 and Comparative Examples 1-3 and Table 6, it can be seen that the relative leaching rates measured in Examples 1-5 are significantly higher than those in Comparative Examples 1-3, indicating that after adding the polycarboxylate water-reducing agent with a lignin group in the stirring leaching process, the copper dissolution effect can be more fully improved. This is because the polycarboxylate water-reducing agent can be adsorbed with the mud minerals doped in the copper oxide ore. Under the action of steric hindrance, the polycarboxylate water-reducing agent can hinder the agglomeration of the mud minerals, improve the dispersion effect of the mud minerals, reduce the obstruction of the mud minerals to the dissolution of copper, and the stirring leaching method itself also contributes to the sufficient dissolution of copper.

[0052] Combining Example 1 and Comparative Example 1 with Table 6, it can be seen that when the polycarboxylate water-reducing agent is missing, it is still difficult to fully improve the dissolution effect of copper by stirring leaching alone.

[0053] Combining Example 1 and Comparative Example 2 with Table 6, it can be seen that when the polycarboxylate water-reducing agent lacks lignin groups, the copper dissolution effect can only be slightly improved, but it is still difficult to reach the level of Example 1.

[0054] Combining Example 1 and Comparative Example 3 with Table 6, it can be seen that when the muddy ore is leached by heap leaching, even if a polycarboxylate water-reducing agent with a lignin group is added, the copper leaching rate is still relatively limited, significantly lower than the leaching rate measured by stirring leaching.

[0055] Combining Example 5 and Example 6 with Table 6, it can be seen that the relative leaching rate measured in Example 6 is higher. This is because the sodium gluconate molecule is smaller and has a similar adsorption mechanism to the polycarboxylate water-reducer. Therefore, while sodium gluconate occupies a portion of the adsorption sites on the surface of the argillaceous mineral particles, it also reduces the excessive aggregation of the polycarboxylate water-reducer on the surface of the argillaceous mineral, improves the dispersion effect of the polycarboxylate water-reducer, and fully reduces the obstruction of the argillaceous mineral to the dissolution of copper.

[0056] Combining Example 6 and Example 7 with Table 6, it can be seen that the relative leaching rate measured in Example 7 is higher. This is because sodium lignin sulfonate and the polycarboxylate water-reducing agent of the present application contain similar lignin groups, and there is a synergistic effect between the two, thereby fully reducing the obstruction of the dissolution of copper caused by muddy minerals.

[0057] Combining Examples 7, 8-10 and Table 6, it can be seen that when the amount of sodium lignin sulfonate is 3-5% by weight of the polycarboxylate water-reducing agent, it helps to fully reduce the obstruction of copper dissolution caused by muddy minerals.

[0058] It can be seen from Example 10, Examples 11-13 and Table 6 that in step (2) of the process, when the sulfuric acid concentration of the acid leaching solution is 1.8-2.2 mol / L, it is helpful to fully achieve the leaching of copper.

[0059] It can be seen from Example 13, Examples 14-16 and Table 6 that in step (2) of the process, when the weight ratio of the acid leaching solution to the muddy ore is (3.5-4.2):1, it is helpful to fully achieve the leaching of copper.

[0060] It can be seen from Example 16, Examples 17-19 and Table 6 that in step (2) of the process, when the stirring rate during stirring leaching is 240-320 r / min, it is helpful to fully achieve the leaching of copper.

[0061] The above embodiments are merely explanations of the present application and are not limitations of the present application. After reading this specification, those skilled in the art may make modifications to the embodiments of the present application as needed without any creative contribution. However, as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A process for extracting and purifying copper from copper oxide ore, characterized in that: The following steps are involved: (1) Crushing the copper oxide ore, washing and classifying it to obtain lump ore and mud ore; (2) Heap leaching the bulk ore to obtain a first leachate; mixing the muddy ore and the anti-clay composition, adding the mixture to an acid leaching solution, stirring and leaching, to obtain a second leachate; in this step, the anti-clay composition comprises a polycarboxylate water reducer having lignin groups grafted into its molecules, and the amount of the polycarboxylate water reducer is 0.3-0.6% of the total weight of the muddy ore; (3) Using an organic extractant to extract the mixture of the first leachate and the second leachate, and then using sulfuric acid to back-extract the organic phase to obtain a copper-rich solution, and then electrolytically processing the copper-rich solution to obtain a cathode copper product.

2. The process for extracting and purifying copper from copper oxide ore according to claim 1, characterized in that: The polycarboxylate water reducer is prepared according to the following method: (1) Add acrylic acid monomer and ascorbic acid into water and mix to obtain liquid A; add initiator and mercaptoethanol into water and mix to obtain liquid B; (2) Add unsaturated ester of lignin and alkenyl polyoxyethylene ether into water and mix them. After heating, add sodium lauryl sulfate, and then dropwise add liquid A and liquid B. After the addition is completed, continue to keep warm and react. After the reaction is completed, use sodium hydroxide to adjust the pH value. After the product is dialyzed and intercepted and rotary evaporated to obtain a polycarboxylic acid water reducer.

3. The process for extracting and purifying copper from copper oxide ore according to claim 2, characterized in that: The unsaturated ester of lignin is prepared according to the following method: Alkali lignin is added to DMSO and dissolved to obtain a lignin solution; the lignin solution is placed in an ice-water bath in a nitrogen atmosphere, and then triethylamine and acryloyl chloride are added to the lignin solution in sequence. After heat preservation and reaction, the product is precipitated and separated using a saturated sodium bicarbonate solution, and then filtered and the filter cake is washed to obtain an unsaturated ester of lignin.

4. The process for extracting and purifying copper from copper oxide ore according to claim 3, characterized in that: The weight of the unsaturated lignin ester is 1.5-3.5% of the weight of the alkenyl polyoxyethylene ether.

5. The process for extracting and purifying copper from copper oxide ore according to claim 2, characterized in that: The anti-clay composition also includes sodium gluconate as a component.

6. The process for extracting and purifying copper from copper oxide ore according to claim 2, characterized in that: The anti-clay composition also includes sodium lignin sulfonate as a component.

7. The process for extracting and purifying copper from copper oxide ore according to claim 6, characterized in that: The amount of sodium lignin sulfonate used is 3-5% by weight of the polycarboxylate water reducer.

8. The process for extracting and purifying copper from copper oxide ore according to claim 1, characterized in that: In step (2) of the process, the sulfuric acid concentration of the pickling solution is 1.8-2.2 mol / L.

9. The process for extracting and purifying copper from copper oxide ore according to claim 8, characterized in that: In step (2) of the process, the weight ratio of the acid leaching solution to the muddy ore is (3.5-4.2):

1.

10. The process for extracting and purifying copper from copper oxide ore according to claim 9, characterized in that: In step (2) of the process, the stirring rate during stirring and leaching is 240-320 r / min.

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