Biological leaching purification process for ore difficult to treat

Abstract

The bioleaching purification process comprises the following steps: culturing and domesticating microorganisms: adding the microorganisms into a 9K culture medium, culturing by taking ferrous sulfate and elemental sulfur as metabolic energy sources, and performing acclimatization on acid resistance, copper ion concentration and chalcopyrite pulp concentration to obtain acclimatized microorganisms; the microorganisms are moderate thermophilic bacteria, and carrying out biological leaching and extraction: extracting copper from the leaching liquid in the rich liquid pool. According to the method, the biological leaching rate and leaching rate of the copper ore can be increased.

Description

Technical Field

[0001] The invention relates to the technical field of ore resource hydrometallurgy, and in particular to a bioleaching and purification process for difficult-to-treat ores. Background Art

[0002] At present, my country's copper mines are mainly sulfide ores, and sulfide copper ores are mainly chalcopyrite. With the continuous exploitation of mineral resources, the ore has gradually tended to be poor and mixed, the ore grade is low, and the co-existence relationship is complex. It is urgent to accelerate the improvement of low-grade ore resource development capabilities, achieve economical and efficient development, and ensure the safety of ore resources.

[0003] Bioleaching is a hydrometallurgical technology developed in recent years. It refers to the process of using leaching microorganisms (bacteria, archaea and fungi) to dissolve valuable metal ions in ore into the leachate. It can effectively treat various low-grade copper ores and has the characteristics of low production cost, low environmental pollution and simple operation. In today's world, where high-grade copper resources are becoming increasingly scarce, bioleaching has shown great advantages. However, copper ores are mainly secondary sulfide ores and oxide ores. As a primary sulfide ore, chalcopyrite has a lattice energy much higher than any other copper sulfide ore. Therefore, its bioleaching rate and leaching rate are not ideal. This is mainly because chalcopyrite is prone to passivation on the surface during bioleaching, and an obvious elemental sulfur-iron-vanadium passivation layer appears, which will affect the bioleaching rate and leaching rate of copper ore, thereby further affecting the extraction of copper. Summary of the invention

[0004] The object of the present invention is to provide a bioleaching purification process for difficult-to-treat ores, which can improve the bioleaching rate and leaching speed of copper ore.

[0005] To achieve the above-mentioned object, the present invention provides the following technical scheme: A bioleaching and purification process for difficult-to-treat ores, comprising the following steps: microbial culture and domestication: adding microorganisms to 9K culture medium, culturing with ferrous sulfate and elemental sulfur as metabolic energy sources, and domesticating the microorganisms to acid resistance, copper ion concentration and chalcopyrite slurry concentration, wherein the microorganisms are moderately thermophilic bacteria;

[0006] Bioleaching: Bioleaching is carried out by heap leaching. A ventilation pipe is set at the bottom of the chalcopyrite pile. The liquid distribution system is a sprinkler. The initial leaching temperature is room temperature. The initial pH value of leaching is 1.4. Acid is continuously added to maintain the balance between acid consumption and acid production in the system. Acid addition is stopped. When the copper concentration in the leaching solution reaches a predetermined value, it is extracted to the rich liquid pool for copper extraction.

[0007] Extraction: Extract copper from the leaching solution in the rich liquid pool.

[0008] As a preferred embodiment of the present technical solution, the components and concentrations of the 9K culture medium are: (NH4)2S04 3.0 g / L, Na2S04 2.1 g / L, MgS04·7H20 0.5 g / L, K2HP04 0.05 g / L, KCL 0.1 g / L and Ca(N03)2 0.01 g / L.

[0009] As a preferred embodiment of the present technical solution, the temperature of the microorganism culture is 45-48°C, the pH value is 2.0, and the culture is shaken on a shaker at 180-200 r / min.

[0010] As a preferred embodiment of the present technical solution, yeast powder or peptone is added during the microbial culture.

[0011] As a preferred embodiment of the present technical solution, the microorganism culture time is 7 days.

[0012] As a preferred embodiment of the present technical solution, the extraction is performed by extraction and electrowinning in a biological leaching solution to obtain a copper product.

[0013] Compared with the prior art, the present invention adopts moderate thermophilic bacteria for cultivation and domestication. The moderate thermophilic bacteria can effectively dissolve the elemental sulfur produced during the oxidation of chalcopyrite, reduce the sulfur mold accumulated on the surface of the mineral, and improve the leaching rate. The moderate thermophilic bacteria are acid-resistant domesticated so that they grow well under acidic conditions, thereby being able to better dissolve jarosite precipitates, which is beneficial to the elimination or reduction of jarosite passivation films during the biological leaching process, and improving the biological leaching rate and leaching rate. DETAILED DESCRIPTION

[0014] The technical solution will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased on the market.

[0015] Example 1: The bioleaching and purification process for difficult-to-treat ores of the present invention comprises the following steps: microbial culture and domestication, bioleaching and extraction, wherein moderately thermophilic microorganisms are collected from acidic mine water of various open-pit copper-sulfur mines, mixed, and enriched using 9K culture medium, wherein the components and concentrations of the 9K culture medium are: (NH4)2S04 3.0 g / L, Na2S04 2.1 g / L, MgS04·7H20 0.5 g / L, K2HP04 0.05 g / L, KCL 0.1 g / L and Ca(N03)2 0.01 g / L, and cultured for 7 days. During acclimatization, the moderately thermophilic enrichment in the logarithmic growth phase was inoculated into 9K medium at a 10% inoculum amount, and 10 g / L of ferrous sulfate, 3 g / L of elemental sulfur and 5 g / L of chalcopyrite were added. The culture temperature was 48°C, and the pH value was adjusted to 2.0 with sulfuric acid. The culture was shaken on a shaker at 180 r / min. The pH value dropped to 1.6 and the bacterial concentration exceeded 10 8 / mL, filter out the slag, collect the leaching solution, and carry out the second and third acclimatization. Each time the amount of ferrous sulfate and elemental sulfur gradually decreases, and the amount of chalcopyrite gradually increases, until the maximum strain concentration can be reached within 10 days under the condition that only chalcopyrite is used as an energy substance.

[0016] The composition of the chalcopyrite sample in this example is Cu 0.6%, Fe 3.14%, S1.01%, SiO2

[0017] 62.3%, Al2O3 10.8%, CaO 3.38%, MgO 3.02%, K2O 4.26%, Na2O 0.89%. The particle size of the ore in the ore pile is 5mm, the height of the ore pile is 5m, the aeration pipeline is aerated 4 times a day, each time for 1 hour, the aeration intensity is 360L / min, and the dilute acid solution is used for pre-leaching at the beginning of leaching. After stabilization, the strain is inoculated. When the copper ion concentration in the leachate is 8g / L, the leachate is extracted into the rich liquid pool, and the copper product is extracted by extraction and electrowinning. This embodiment is tested, and the leaching concentration of copper is 14.3g / L, and the leaching rate is 64.6%.

[0018] Example 2: The bioleaching and purification process for difficult-to-treat ores of the present invention comprises the following steps: microbial culture and domestication, bioleaching and extraction, wherein moderately thermophilic microorganisms are collected from acidic mine water of various open-pit copper-sulfur mines, mixed, and enriched using 9K culture medium, wherein the components and concentrations of the 9K culture medium are: (NH4)2S04 3.0 g / L, Na2S04 2.1 g / L, MgS04·7H20 0.5 g / L, K2HP04 0.05 g / L, KCL 0.1 g / L and Ca(N03)2 0.01 g / L, and cultured for 7 days. During acclimatization, the moderately thermophilic enrichment in the logarithmic growth phase was inoculated into 9K medium at a 10% inoculum amount, and 10 g / L of ferrous sulfate, 3 g / L of elemental sulfur and 5 g / L of chalcopyrite were added. The culture temperature was 45°C, the pH value was adjusted to 2.0 with sulfuric acid, and the culture was shaken on a shaker at 200 r / min. The pH value dropped to 1.6 and the bacterial concentration exceeded 10 8 / mL, filter out the slag, collect the leaching solution, and carry out the second and third acclimatization. Each time the amount of ferrous sulfate and elemental sulfur gradually decreases, and the amount of chalcopyrite gradually increases, until the maximum strain concentration can be reached within 10 days under the condition that only chalcopyrite is used as an energy substance.

[0019] In this embodiment, the composition of the chalcopyrite sample is Cu 0.4%, Fe 3.25%, S1.1%, SiO2 64.5%, Al2O314.8%, CaO 3.38%, MgO 4.12%, K2O 4.46%, Na2O 0.85%. The particle size of the ore in the ore pile is 6mm, the height of the ore pile is 3m, the aeration pipeline is aerated 4 times a day, each time for 1 hour, the aeration intensity is 360L / min, and the dilute acid solution is used for pre-leaching at the beginning of leaching, and after stabilization, the strain is inoculated. When the copper ion concentration in the leachate is 9g / L, the leachate is extracted into the rich liquid pool, and the copper product is extracted by extraction and electrowinning. This embodiment is tested, and the leaching concentration of copper is 15.5g / L, and the leaching rate is 68.3%.

[0020] Embodiment 3: The bioleaching and purification process for difficult-to-treat ores of the present invention comprises the following steps: microbial culture and domestication, bioleaching and extraction, wherein moderately thermophilic microorganisms are collected from acidic mine water of various open-pit copper-sulfur mines, mixed, and enriched using 9K culture medium, wherein the components and concentrations of the 9K culture medium are: (NH4)2S04 3.0 g / L, Na2S04 2.1 g / L, MgS04·7H20 0.5 g / L, K2HP04 0.05 g / L, KCL 0.1 g / L and Ca(N03)2 0.01 g / L, and cultured for 7 days, during which 0.4 g / L yeast powder or peptone is added. During acclimatization, the moderately thermophilic enrichment in the logarithmic growth phase was inoculated into 9K medium at a 10% inoculum amount, and 10 g / L of ferrous sulfate, 3 g / L of elemental sulfur and 5 g / L of chalcopyrite were added. The culture temperature was 46°C, and the pH value was adjusted to 2.0 with sulfuric acid. The culture was shaken on a shaker at 190 r / min. The pH value dropped to 1.6 and the bacterial concentration exceeded 10 8 / mL, filter out the slag, collect the leaching solution, and carry out the second and third acclimatization. Each time the amount of ferrous sulfate and elemental sulfur gradually decreases, and the amount of chalcopyrite gradually increases, until the maximum strain concentration can be reached within 10 days under the condition that only chalcopyrite is used as an energy substance.

[0021] In this embodiment, the composition of the chalcopyrite sample is Cu 0.5%, Fe 3.15%, S2.1%, SiO2 62.5%, Al2O311.8%, CaO 4.18%, MgO 5.12%, K2O 4.16%, Na2O 0.65%. The particle size of the ore in the ore pile is 4mm, the height of the ore pile is 4m, the aeration pipeline is aerated 4 times a day, each time for 1 hour, the aeration intensity is 360L / min, and the dilute acid solution is used for pre-leaching at the beginning of leaching, and after stabilization, the strain is inoculated. When the copper ion concentration of 10g / L is measured in the leachate, the leachate is extracted into the rich liquid pool, and the copper product is extracted by extraction and electrowinning. This embodiment is tested, and the leaching concentration of copper is 11.g / L, and the leaching rate is 52.8%.

Claims

1. A bioleaching purification process for difficult-to-treat ores, It is characterized in that The following steps are involved: Microbial cultivation and domestication: adding microorganisms to 9K culture medium, cultivating them with ferrous sulfate and elemental sulfur as metabolic energy, and domesticating them to acid resistance, copper ion concentration and chalcopyrite slurry concentration, wherein the microorganisms are moderately thermophilic bacteria; Bioleaching: Bioleaching is carried out by heap leaching. A ventilation pipe is set at the bottom of the chalcopyrite pile. The liquid distribution system is a sprinkler. The initial leaching temperature is room temperature. The initial pH value of leaching is 1.

4. Acid is continuously added to maintain the balance between acid consumption and acid production in the system. Acid addition is stopped. When the copper concentration in the leaching solution reaches a predetermined value, it is extracted to the rich liquid pool for copper extraction. Extraction: Extract copper from the leaching solution in the rich liquid pool.

2. The bioleaching purification process according to claim 1, Features: The components and concentrations of the 9K medium are: (NH 4 ) 2 S0 4 3.0g / L, Na 2 S0 4 2.1g / L,MgS0 4 7H 2 0 0.5 g / L, K 2 HP0 4 0.05g / L, KCL 0.1g / L and Ca(N0 3 ) 2 0.01g / L.

3. The bioleaching purification process according to claim 2, Features: The temperature of the microorganism culture is 45-48°C, the pH value is 2.0, and the culture is shaken on a shaker at 180-200 r / min.

4. The bioleaching purification process according to claim 1, Features: Yeast powder or peptone is added during microbial culture.

5. The bioleaching purification process according to claim 2, Features: The microbial culture time is 7 days.

6. The bioleaching purification process according to claim 1, Features: The extraction is to extract and electrolyze in the biological leaching solution to obtain the copper product.