Ferrous oxide microbial complex microbial inoculant and application thereof in treatment of refined copper slag

Abstract

The invention relates to a ferrous oxide composite microbial inoculant and application thereof. The complex microbial inoculants comprise thiobacillus ferrooxidans microorganisms and leptospirillum ferrooxidans microorganisms. The composite microbial inoculant has the advantages of environmental friendliness, high tolerance, high adaptability and the like. The microbial complex microbial inoculant can normally grow in a 9K culture medium with the refined copper slag concentration of 22 g / L. Therefore, the composite microbial inoculant is suitable for copper metal leaching of the refined copper slag under different conditions. The microbial complex microbial inoculant contributes to secondary utilization and cyclic utilization of copper metal resources in the refined copper slag and effective protection of the ecological environment of a mining area, achieves the win-win situation of obtaining economic benefits and being environmentally friendly, is green and pollution-free, does not cause secondary pollution after copper metal is leached, and has a good application prospect. Therefore, the compound microbial inoculant is an ideal and efficient compound microbial inoculant in the aspect of biological metallurgy, and can be widely applied to the field of biological metallurgy.

Description

Technical Field

[0001] The present invention belongs to the field of bioleaching, and particularly relates to a ferrous oxide microbial composite bacterium agent and its use in the treatment of refined copper slag. Background Art

[0002] At present, there are mainly four treatment technologies for recovering metals from electronic waste at home and abroad, namely mechanical treatment technology, heat treatment technology, hydrometallurgy technology and biotechnology. These technologies have achieved certain effects to a certain extent. However, the first three methods generally have a low metal recovery rate, cannot completely separate metals, and are prone to cause secondary pollution to the environment. The biosorption method has many advantages such as high efficiency, low cost, low energy consumption, and no secondary pollution in recovering precious metals from electronic waste, making it one of the most promising technologies. Taking copper metal as an example, the most abundant chalcopyrite usually has a low grade, and the high cost of conventional high-temperature smelting makes it difficult to realize its economic value. However, its composition is complex and its crystal structure is dense, and there are also problems such as long leaching cycle and low efficiency in the biological leaching process. At the same time, the waste slag produced after the refined copper process itself contains 0.25%-1% of copper elements, which cannot be extracted for a long time due to the limitations of flotation agents and flotation technologies. Therefore, it is imperative to recover metals such as copper from refined copper slag and realize the secondary utilization of metals. Biological leaching is a biochemical process in which microorganisms and metals react with each other, and its main functional microorganism is acidophilic iron-oxidizing bacteria. In the leaching of refined copper slag, acidophilic iron-oxidizing bacteria can oxidize ferrous in the leaching system to produce ferric ions, which act as oxidants to attack the elemental copper in the refined copper slag, releasing ferrous ions and copper ions. Therefore, the growth of such microorganisms during the leaching process is very important. At present, the common drawbacks of the strains used in biological leaching are: short leaching time limit. As time goes by, the leaching efficiency gradually decreases and finally stops, and the overall efficiency is low. And due to the continuous fluctuation of chemical parameters during the leaching process, the proportion of the strains also continuously changes during the whole leaching process. How to better balance the microbial proportion of iron-oxidizing strains at different stages so that they can play the greatest efficiency during the leaching process requires intervening and regulating the leaching process of such functional microorganisms by means of external sources according to the growth of microorganisms and the changes of chemical parameters during the leaching process. In the process of extracting copper metal from lean ore by leaching method, biological bacterium agents have been widely used and have a certain leaching effect. However, in the treatment of refined copper slag, due to the insufficient tolerance of the strains to flotation agents and their own oxidizability, the biological leaching method has not been applicable to further extract copper metal. Therefore, it is very meaningful to study an easily obtainable microbial composite bacterium agent for leaching and recovering copper metal from refined copper slag, and it is imperative to invent a high-efficiency, low-consumption and easily obtainable microbial composite bacterium agent.

[0003] Therefore, it is of great significance to further explore methods to enhance the leaching of copper metal from refined copper slag based on microbial growth and chemical regulation, starting from improving the microbial efficiency of iron-oxidizing bacteria, improving the growth of microorganisms and the activity of iron metabolism in the bioleaching process, and ultimately enhancing the leaching efficiency of refined copper slag.

[0004] Note: Refined copper slag, also known as copper tailings slag, is one of the main waste residues in pyrometallurgical copper production. It is the residue remaining after the flotation process of copper ore, mainly composed of iron tetroxide and silicon dioxide. Depending on the flotation process, it contains 0.25%-1% copper and trace amounts of associated metals such as nickel, gold, and silver. Currently, there is no effective disposal method in China, and it is mainly stacked (i.e., the so-called tailings pond). Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides an iron-oxidizing microbial complex bactericide and its application. A biological treatment method for leaching different metals in refined copper slag through the mixed action of two ore-leaching microorganisms, which is applicable to the leaching of metals in refined copper slag. It can effectively protect the ecological environment and make efficient use of resources. The microbial bactericide of the present invention has the advantages of being conducive to the recovery and utilization of metal resources, environmental protection, long-lasting leaching effect, high tolerance rate to refined copper slag, high leaching efficiency, and strong stability of the microbial bactericide.

[0006] The technical solution of the present invention to solve the above technical problems is as follows: An iron-oxidizing microbial complex bactericide, comprising Thiobacillus ferrooxidans microorganisms and Leptospirillum ferrooxidans microorganisms.

[0007] The beneficial effects of the present invention are: The present invention provides a biological treatment method for leaching copper metal in refined copper slag through the mixed action of two ore-leaching microorganisms, which is applicable to the leaching of metals in refined copper slag. It can effectively protect the ecological environment and make efficient use of resources. The microbial bactericide of the present invention has the advantages of being conducive to the recovery and utilization of metal resources, environmental protection, long-lasting leaching effect, high tolerance rate to refined copper slag, high leaching efficiency, and strong stability of the microbial bactericide.

[0008] On the basis of the above technical solution, the present invention can also be improved as follows.

[0009] Furthermore, the Acidithiobacillus ferrooxidans microorganisms are selected from one or more of the following 44 microorganisms with preservation numbers; the 44 microorganisms with preservation numbers are respectively: CCTCC AB206199, CCTCC AB206200, CCTCC AB206201, CCTCC AB206202, CCTCC AB206203, CCTCC AB206204, CCTCC AB206205, CCTCC AB206206, CCTCC AB206207, CCTCC AB206208, CCTCC AB207053, CCTCC AB207054, CCTCC AB207055, CCTCC AB207056, CCTCC AB207057, CCTCC AB207058; ATCC13598D, ATCC53987, ATCC23270, ATCC53982, ATCC53983, ATCC14119, ATCC19859, ATCC33020, ATCC21834, ATCC13728, ATCC13661; DSM-2390, DSM-1931, DSM-14882, DSM-1928, DSM-1929, DSM-2389, DSM-700, DSM-2613, DSM-29444, DSM-9464, DSM-11477, DSM-24419, DSM-9465, DSM-1927, DSM-584, DSM-583, DSM-585. The beneficial effects of adopting the above solution are: The microorganisms with the above preservation numbers are beneficial to further improving the leaching efficiency, the tolerance rate to refined copper slag, the high leaching efficiency and the stability of the microbial agent.

[0010] Furthermore, the Leptospirillum ferrooxidans microorganisms are selected from one or more of the following 20 microorganisms with preservation numbers; the 20 microorganisms with preservation numbers are respectively: CCTCC AB206158, CCTCC AB206159, CCTCC AB206160, CCTCC AB206161, CCTCC AB206162, CCTCC AB206163, CCTCC AB206164, CCTCC AB207036, CCTCC AB207037, CCTCC AB207038; ATCC53992, ATCC29047, ATCC49879, ATCC49880, ATCC53993; DSM-2391, DSM-2705, DSM-1937, DSM-1929, DSM-1928. The beneficial effects of adopting the above scheme are as follows: The microorganism with the above preservation number is beneficial to further improve the leaching efficiency, the tolerance rate to refined copper slag, the high leaching efficiency and the stability of the microbial agent.

[0011] Furthermore, the cell number ratio of Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans is (1 - 3):(3 - 1).

[0012] The beneficial effects of adopting the above scheme are as follows: Adopting the above ratio is beneficial to further improve the leaching efficiency, the tolerance rate to refined copper slag, the high leaching efficiency and the stability of the microbial agent.

[0013] Furthermore, the cell number ratio of Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans is 1:1 or 1:2 or 1:3 or 2:1 or 3:1.

[0014] The beneficial effects of adopting the above scheme are as follows: Adopting the above ratio is beneficial to further improve the leaching efficiency, the tolerance rate to refined copper slag, the high leaching efficiency and the stability of the microbial agent.

[0015] The present invention provides the application of the above Acidithiobacillus ferrooxidans microbial complex agent in metal leaching. It is particularly suitable for leaching metals in refined copper slag.

[0016] The beneficial effects of adopting the above scheme are as follows: The microbial complex agent provided by the present invention can be applied in metal leaching. It is particularly suitable for leaching metals in refined copper slag, which is convenient for recycling and secondary utilization, and solves the problem of serious metal pollution caused by refined copper slag. It can also be further widely applied in environmental protection. For example, in the specific implementation process, Fe3+ obtained by oxidizing Fe2+ oxidizes H2S waste gas, thus realizing the treatment of H2S waste gas. The microbial complex agent of the present invention can be widely applied in the fields of environmental protection and metal leaching from refined copper slag, etc. It has the advantages of being conducive to metal recycling, environmental protection, high metal leaching rate, high tolerance rate to refined copper slag, etc. The microbial complex agent provided by the present invention can grow normally in an environment with a refined copper slag concentration of 22 g / L.

[0017] The present invention also provides a method for leaching metals using the above Acidithiobacillus ferrooxidans microbial complex agent, including the following steps: inoculating the above Acidithiobacillus ferrooxidans microbial complex agent in 9K medium, adding refined copper slag to the 9K medium, and performing fermentation culture.

[0018] The beneficial effects of adopting the above scheme are as follows: Adopting the above method for leaching metals has the advantages of being conducive to metal resource recycling, environmental protection, long-lasting leaching efficiency, high tolerance rate to refined copper slag, high leaching efficiency, and strong stability of the microbial agent.

[0019] Furthermore, during fermentation culture, the culture temperature is 35 - 45 °C.

[0020] The beneficial effects of adopting the above solution are as follows: The above-mentioned culture temperature is conducive to the growth of the bacterial cells. If the temperature is too low, it will lead to the problem of slow or no growth of the bacterial cells. If the temperature is too high, it will also lead to the problem of slow or even no growth of the bacterial cells.

[0021] Furthermore, in the 9K culture medium, the initial concentration of Fe2+ is 10 - 30 g / L.

[0022] The beneficial effects of adopting the above solution are as follows: An appropriate concentration of Fe2+ is conducive to the growth of the bacterial cells. If the concentration of Fe2+ is too low, it is likely to cause the problem of slow growth of the bacterial cells. If the concentration of Fe2+ is too high, it is also likely to cause the problem of slow growth of the bacterial cells.

[0023] Furthermore, the initial pH value of the culture medium is 2.0 - 3.0, the fermentation culture time is 10 - 30 days, and the shaking speed of the shaker during fermentation culture is 120 - 180 rpm.

[0024] The beneficial effects of adopting the above solution are as follows: The above-mentioned culture conditions are conducive to the growth of the bacterial cells. If the pH value is too low, it is likely to cause the problem of slow or no growth of the bacterial cells. If the pH value is too high, it is likely to cause the problem of slow growth of the bacterial cells.

[0025] Specifically, the biological leaching recovery method of refined copper slag using the described leaching microbial complex agent may include the following steps: (1) Pretreatment of refined copper slag The refined copper slag to be used for leaching is pretreated to remove the residual flotation agent attached to the surface. Generally, methods such as washing with water and drying in the sun can be used.

[0026] (2) Preparation of the microbial complex agent This microbial complex agent is composed of a Thiobacillus ferrooxidans microorganism and a Leptospirillum ferrooxidans microorganism. The optimal ratio of the cell numbers of the Thiobacillus ferrooxidans microorganism and the Leptospirillum ferrooxidans microorganism is preferably 1:1 or 1:2 or 1:3 or 2:1 or 3:1.

[0027] (3) Metal leaching of refined copper slag The refined copper slag is added to the 9K culture medium containing the microbial complex agent and placed in a shaker for cultivation. The cultivation conditions are as follows: the pH value is 2.0 - 3.0, the cultivation temperature is 35 - 45 °C, the cultivation time is 20 - 30 days, the initial concentration of Fe2+ is 10 - 30 g / L, and the shaking speed of the shaker is 180 rpm.

[0028] (4) Measure the leaching solution obtained in the above steps. Before measurement, shake well, let it stand, and then take 0.1 mL of the leaching solution and dilute it to 60 mL with distilled water. Use a test kit (Guangdong Kaiwei Microbial Technology Co., Ltd.) to measure the concentrations of copper ions and nickel ions (if present).

[0029] In the refined copper slag treatment method described in step (1), in the present invention, the refined copper slag can also be directly used for leaching. However, the flotation agent is generally an organic reagent and there are differences in the reagents used in different flotation methods. To avoid the influence of uncertain factors on the bacterial agent, it should be removed as much as possible.

[0030] The microbial composite bacterial agent described in step (2) has the following advantages in such preparation: it has high iron oxidation activity, and avoids the problems of repulsion between strains and low efficiency. This microbial composite bacterial agent can be used as a whole, with the advantages of high stability, strong environmental adaptability, high leaching efficiency, and simple preparation. It can effectively and low-consumedly leach the metals in the refined copper slag, which is convenient for recovery and secondary utilization.

[0031] In the method described in step (3), the microbial composite bacterial agent uses CO2 as a carbon source during the leaching process, oxidizes Fe2+ in the leaching solution to Fe3+, and the metal ions are converted from a fixed state to a free ionic state. The ionic state of the metal can be extracted and recovered by displacement reaction.

[0032] In the leaching process described in steps (1), (2), (3), and (4), the concentration of the refined copper slag added does not exceed 22 g / L.

[0033] A 9K medium with a specific Fe2+ concentration can be prepared according to the following ratio. For example, to prepare a 9K medium with an Fe2+ concentration of 30 g / L, the formula can be: 0.3 g (NH4)2SO4, 0.1 g KCl, 0.5 g K2HPO4, 0.5 g MgSO4·7H2O, 0.01 g Ca(NO3)2, 30 g FeSO4·7H2O, and 1000 mL of distilled water. Finally, adjust the pH value to 1.5 - 2.0 with 0.5 mol / L H2SO4 to obtain the 9K medium. Detailed implementation mode The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0035] Unless otherwise defined, all professional terms used hereinafter in the technical solution of the present invention have the same meaning as commonly understood by those skilled in the art.

[0036] The technical terms used in this article are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention. Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment, etc. used in the present invention can be obtained through market purchase or can be prepared by existing methods. It is not limited to the specific embodiments listed below, but also includes any combination between specific embodiments.

[0037] The present invention provides an iron-oxidizing microbial composite bacterium agent and its use for leaching metals from refined copper slag, which relates to an iron-oxidizing microbial composite bacterium agent and its use for leaching metals from refined copper slag. At present, the single-strain and composite-strain microorganisms used in the research of biological leaching, whether single-strain or composite-strain, have the disadvantage of short leaching time limit. From the beginning of the leaching process, as time goes by, the leaching ability of the strains gradually decreases, and few strains can maintain their leaching activity after continuous leaching for 28 days.

[0038] However, the iron-oxidizing microbial composite bacterium agent provided in this application can still maintain an Fe2+ oxidation rate of more than 70% after 35 days of leaching. When the leaching time is 28 days, the Fe2+ oxidation rate is the highest, reaching 97.78%.

[0039] The Acidithiobacillus ferrooxidans mentioned above is one or more of 44 strains with deposit numbers of CCTCC AB206199, CCTCC AB206200, CCTCC AB206201, CCTCC AB206202, CCTCC AB206203, CCTCC AB206204, CCTCC AB206205, CCTCC AB206206, CCTCC AB206207, CCTCC AB206208, CCTCC AB207053, CCTCC AB207054, CCTCC AB207055, CCTCC AB207056, CCTCC AB207057, CCTCC AB207058; ATCC13598D, ATCC53987, ATCC23270, ATCC53982, ATCC53983, ATCC14119, ATCC19859, ATCC33020, ATCC21834, ATCC13728, ATCC13661; DSM-2390, DSM-1931, DSM-14882, DSM-1928, DSM-1929, DSM-2389, DSM-700, DSM-2613, DSM-29444, DSM-9464, DSM-11477, DSM-24419, DSM-9465, DSM-1927, DSM-584, DSM-583, DSM-585; the Leptospirillum ferrooxidans mentioned above is one or more of 20 strains with deposit numbers of CCTCC AB206158, CCTCC AB206159, CCTCC AB206160, CCTCC AB206161, CCTCC AB206162, CCTCC AB206163, CCTCC AB206164, CCTCC AB207036, CCTCC AB207037, CCTCC AB207038; ATCC53992, ATCC29047, ATCC49879, ATCC49880, ATCC53993; DSM-2391, DSM-2705, DSM-1937, DSM-1929, DSM-1928. The above-mentioned bacterial strains are named as: Acidithiobacillus ferrooxidans CSU206059 (abbreviated as A.f) with deposit number CCTCC AB206199 Acidithiobacillus ferrooxidans CSU206060 (abbreviated as A.f) with deposit number CCTCC AB206200 CCTCC AB206201 Acidithiobacillus ferrooxidans CSU206062 (abbreviation: A.f) CCTCC AB206202 Acidithiobacillus ferrooxidans CSU206064 (abbreviation: A.f) CCTCC AB206203 Acidithiobacillus ferrooxidans CSU206065 (abbreviation: A.f) CCTCC AB206204 Acidithiobacillus ferrooxidans CSU206066 (abbreviation: A.f) CCTCC AB206205 Acidithiobacillus ferrooxidans CSU206068 (abbreviation: A.f) CCTCC AB206206 Acidithiobacillus ferrooxidans CSU206069 (abbreviation: A.f) CCTCC AB206207 Acidithiobacillus ferrooxidans CSU206071 (abbreviation: A.f) CCTCC AB206208 Acidithiobacillus ferrooxidans CSU206073 (abbreviation: A.f) CCTCC AB207053 Acidithiobacillus ferrooxidans CSU206061 (abbreviation: A.f) CCTCC AB207054 Acidithiobacillus ferrooxidans CSU206063 (abbreviation: A.f) CCTCC AB207055 Acidithiobacillus ferrooxidans CSU206067 (abbreviation: A.f) CCTCC AB207056 Acidithiobacillus ferrooxidans CSU206070 (abbreviation: A.f) CCTCC AB207057 Acidithiobacillus ferrooxidans CSU206072 (abbreviation: A.f) CCTCC AB207058 Acidithiobacillus ferrooxidans (referred to as A.f), Acidithiobacillus ferrooxidans CSU206074 ATCC 13598D Acidithiobacillus ferrooxidans (Temple and Colmer) Kelly and Wood ATCC 131598D (referred to as A.f) ATCC 53987 Acidithiobacillus ferrooxidans (Temple and Colmer) Kelly and Wood ATCC 53987 (referred to as A.f) ATCC 23270 Acidithiobacillus ferrooxidans (Temple and Colmer) Kelly and Wood ATCC 23270 (referred to as A.f) ATCC 53982 Acidithiobacillus ferrooxidans (Temple and Colmer) Kelly and Wood ATCC 53982 (referred to as A.f) ATCC 53983 Acidithiobacillus ferrooxidans (Temple and Colmer) Kelly and Wood ATCC 53983 (referred to as A.f) ATCC 14119 Acidithiobacillus ferrooxidans (Temple and Colmer) Kelly and Wood ATCC 14119 (referred to as A.f) ATCC 19859 Acidithiobacillus ferrooxidans (Temple and Colmer) Kelly and Wood ATCC 19859 (referred to as A.f) ATCC 33020 Acidithiobacillus ferrooxidans (Temple and Colmer) Kelly and Wood ATCC 33020 (referred to as A.f) ATCC 21834 Acidithiobacillus ferrooxidans (Temple and Colmer) Kelly and Wood ATCC 21834 (referred to as A.f) ATCC 13728 Acidithiobacillus ferrooxidans (Temple and Colmer) Kelly and Wood ATCC 13728 (abbreviation: A.f) ATCC 13661 Acidithiobacillus ferrooxidans (Temple and Colmer) Kelly and Wood ATCC 13661 (abbreviation: A.f) DSM-2613 Acidithiobacillus ferrooxidans (abbreviation: A.f) DSM-29444 Acidithiobacillus ferrooxidans (abbreviation: A.f) DSM-9464 Acidithiobacillus ferrooxidans (abbreviation: A.f) DSM-11477 Acidithiobacillus ferrooxidans (abbreviation: A.f) DSM-24419 Acidithiobacillus ferrooxidans (abbreviation: A.f) DSM-9465 Acidithiobacillus ferrooxidans (abbreviation: A.f) DSM-1927 Acidithiobacillus ferrooxidans (abbreviation: A.f) DSM-584 Acidithiobacillus ferrooxidans (abbreviation: A.f) DSM-583 Acidithiobacillus ferrooxidans (abbreviation: A.f) DSM-585 Acidithiobacillus ferrooxidans (abbreviation: A.f) DSM-14882 Acidithiobacillus ferrooxidans (abbreviation: A.f) DSM-2390 Acidithiobacillus ferrooxidans (abbreviation: A.f) DSM-1931 Acidithiobacillus ferrooxidans (abbreviation: A.f) DSM-1928 Acidithiobacillus ferrooxidans (abbreviation: A.f) DSM-1929 Acidithiobacillus ferrooxidans (referred to as A.f) DSM-2389 Acidithiobacillus ferrooxidans (referred to as A.f) DSM-700 Acidithiobacillus ferrooxidans (referred to as A.f) CCTCC AB206158 Leptospirillum ferrooxidans CSU206002 (referred to as L.f) CCTCC AB206159 Leptospirillum ferrooxidans CSU206003 (referred to as L.f) CCTCC AB206160 Leptospirillum ferrooxidans CSU206004 (referred to as L.f) CCTCC AB206161 Leptospirillum ferrooxidans CSU206005 (referred to as L.f) CCTCC AB206162 Leptospirillum ferrooxidans CSU206006 (referred to as L.f) CCTCC AB206163 Leptospirillum ferrooxidans CSU206008 (referred to as L.f) CCTCC AB206164 Leptospirillum ferrooxidans CSU206009 (referred to as L.f) CCTCC AB207036 Leptospirillum ferrooxidans CSU206001 (referred to as L.f) ATCC53992 Leptospirillum ferrooxidans (Temple and Colmer) Kelly and Wood ATCC53992 (referred to as L.f) ATCC29047 Leptospirillum ferrooxidans (Temple and Colmer) Kelly and Wood ATCC29047 (referred to as L.f) ATCC 49879 Leptospirillum ferrooxidans (Temple and Colmer) Kelly and Wood ATCC 49879 (abbreviation: L.f) ATCC 49880 Leptospirillum ferrooxidans (Temple and Colmer) Kelly and Wood ATCC 49880 (abbreviation: L.f) ATCC 53993 Leptospirillum ferrooxidans (Temple and Colmer) Kelly and Wood ATCC 53993 (abbreviation: L.f) DSM-2705 Leptospirillum ferrooxidans (abbreviation: L.f) DSM-2391 Leptospirillum ferrooxidans (abbreviation: L.f) DSM-1931 Leptospirillum ferrooxidans (abbreviation: L.f) DSM-1929 Leptospirillum ferrooxidans (abbreviation: L.f) DSM-1928 Leptospirillum ferrooxidans (abbreviation: L.f) Verified by the inventors' experiments, under the following experimental conditions: the initial Fe2+ concentration of the medium is 20 g / L, the pH value is 2.25, the fermentation time is 28 days, the culture temperature is 35 °C, the refined copper slag concentration is 22 g / L, the cell number ratio of Thiobacillus ferrooxidans microorganisms and Leptospirillum ferrooxidans microorganisms is 1:2, and the fermentation time is 28 days. Using the strains with the above preservation numbers for formulation, the Fe2+ oxidation rate is over 97%, the copper leaching rate is 78%-84%, and the nickel leaching rate is 60%-64%.

[0040] The advantages of this microbial complex agent are as follows: artificially formulated, using one kind of Thiobacillus ferrooxidans microorganism and one kind of Leptospirillum ferrooxidans microorganism. These two microorganisms complement each other, there is no exclusion and competition, good stability, simple to obtain, high leaching efficiency, long leaching time limit, and can effectively and low-consumingly leach metals in refined copper slag. Therefore, it can be used for environmental protection and metal leaching.

[0041] According to non-patent literature 1. Liu Jin-yan, Tao Xiu-xiang, Cai Pei, et al. Study of formation of jarosite mediated by thiobacillus ferrooxidans in 9K medium[J]. Procedia Earth and Planetary Science(2009), 706–712; and non-patent literature 2. Qiao Xingxing, Liu Guanlan, Zhou Lixiang, et al. Influence of density of thiobacillus ferrooxidans and nutrient supply on biological oxidation of pyrite[J]. Acta Scientiae Circumstantiae, 2018, (2). etc. reports show that the oxidation rate of Fe2+ can be used as an index to judge the growth of iron-oxidizing bacteria, so the present invention uses the oxidation rate of Fe2+ as the basis for the growth of this microbial complex agent.

[0042] The strains with the above preservation numbers are all commercially available strains. The public can purchase them from the China Center for Type Culture Collection (CCTCC), the American Type Culture Collection (ATCC), and the German Collection of Microorganisms and Cell Cultures (DSMZ).

[0043] Specific Embodiment 1: This microbial complex agent contains a thiobacillus ferrooxidans microorganism and a leptospirillum ferrooxidans microorganism, and the cell number ratio of the thiobacillus ferrooxidans microorganism to the leptospirillum ferrooxidans microorganism is 1:1 or 1:2 or 1:3 or 2:1 or 3:1.

[0044] This microbial complex agent of ferrooxidizing microorganisms in this embodiment is inoculated in 9K medium for cultivation. The 9K medium is obtained by adding 0.3 g of (NH4)2SO4, 0.1 g of KCl, 0.5 g of K2HPO4, 0.5 g of MgSO4·7H2O, 0.01 g of Ca(NO3)2, 10 - 30 g of FeSO4·7H2O, 1000 mL of distilled water, and finally adjusting the pH value to 2.0 - 3.0 with 0.5 mol / L H2SO4. The microbial complex agent of ferrooxidizing microorganisms is inoculated in 9K medium at an inoculation amount of 10% (v / v), and cultured for 20 - 30 days under the conditions that the initial Fe2+ concentration is 10 - 30 g / L, the culture temperature is 30 - 45 °C, and the shaker speed is 180 rpm.

[0045] Experimental results: The suitable culture temperature for the microbial complex agent of the present invention is 30 - 40 °C, and the optimal culture temperature is 35 °C.

[0046] The specific experimental results are shown in Table 1 (experimental conditions: the initial Fe2+ concentration of the medium is 20 g / L, the pH value is 2.25, the fermentation time is 28 days, the refined copper slag concentration is 22 g / L, the cell number ratio of Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans is 1:2, and the strains used are Acidithiobacillus ferrooxidans with the preservation number of ATCC23270 and Leptospirillum ferrooxidans with the preservation number of ATCC29047).

[0047]

[0048] Specific Embodiment 2: The difference between this embodiment and Specific Embodiment 1 is that the culture temperature is 35 °C, and other steps and parameters are the same as those in Embodiment 1.

[0049] Experimental results: The suitable fermentation time of the microbial complex agent of the present invention is 20 - 30 days, and the optimal fermentation time is 28 days. The specific experimental results are shown in Table 2 (experimental conditions: the initial Fe2+ concentration of the medium is 20 g / L, the pH value is 2.25, the fermentation time is 28 days, the culture temperature is 35 °C, the refined copper slag concentration is 22 g / L, the cell number ratio of Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans is 1:2, and the strains used are Acidithiobacillus ferrooxidans with the preservation number of ATCC23270 and Leptospirillum ferrooxidans with the preservation number of ATCC29047).

[0050]

[0051] Specific Embodiment 3: The difference between this embodiment and Specific Embodiment 2 is that the culture time is 28 days, and other steps and parameters are the same as those in Embodiment 2.

[0052] Experimental results: The suitable growth Fe2+ concentration of the microbial complex agent of the present invention is 10 - 30 g / L, and the optimal growth Fe2+ concentration is 20 g / L. The specific experimental results are shown in Table 3 (experimental conditions: the pH value of the medium is 2.25, the fermentation time is 28 days, the culture temperature is 35 °C, the refined copper slag concentration is 22 g / L, the cell number ratio of Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans is 1:2, and the strains used are Acidithiobacillus ferrooxidans with the preservation number of ATCC23270 and Leptospirillum ferrooxidans with the preservation number of ATCC29047).

[0053]

[0054] Specific Embodiment 4: The difference between this embodiment and Embodiment 3 is that the initial Fe2+ concentration of the 9K medium is 20 g / L, and other parameters are the same as those in Embodiment 3.

[0055] Experimental results: The suitable fermentation pH value of the microbial composite bacterium agent of the present invention is 2.0 - 3.0, and the optimal fermentation pH value is 2.25. The specific experimental results are shown in Table 4 (the test conditions are: the initial Fe2+ concentration of the culture medium is 20 g / L, the fermentation time is 28 days, the culture temperature is 35 °C, the refined copper slag concentration is 22 g / L, the cell number ratio of Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans is 1:2, and the used strains are Acidithiobacillus ferrooxidans with the preservation number of ATCC23270 and Leptospirillum ferrooxidans with the preservation number of ATCC29047).

[0056]

[0057] The technical solution of the present invention will be introduced below through specific examples.

[0058] In Examples 1 to 6, the 9K culture medium was prepared in the following proportion: 0.3 g of (NH4)2SO4, 0.1 g of KCl, 0.5 g of K2HPO4, 0.5 g of MgSO4·7H2O, 0.01 g of Ca(NO3)2, 20 g of FeSO4·7H2O, and 1000 mL of distilled water. Finally, the pH value was adjusted to 2.25 with 0.5 mol / L H2SO4 to obtain the 9K culture medium.

[0059] Example 1 The Acidithiobacillus ferrooxidans microbial composite bacterium agent is composed of one Acidithiobacillus ferrooxidans and one Leptospirillum ferrooxidans. The cell number ratio of Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans is 1:2, and the used strains are Acidithiobacillus ferrooxidans with the preservation number of ATCC23270 and Leptospirillum ferrooxidans with the preservation number of ATCC29047).

[0060] The Acidithiobacillus ferrooxidans microbial composite bacterium agent was inoculated into the 9K culture medium at an inoculation amount of 10% (v / v), and refined copper slag was added to the 9K culture medium. Fermentation culture was carried out for 100 hours under the conditions of a culture temperature of 35 °C, a shaker speed of 180 rpm, an initial Fe2+ concentration of 20 g / L, and a pH value of 2.25.

[0061] The added refined copper slag concentrations were 1 g / L, 5 g / L, 10 g / L, 15 g / L, 20 g / L, 22 g / L, 30 g / L, 35 g / L, and 45 g / L respectively.

[0062] It was found that the microbial complex agent of the present invention could still grow normally in the 9K medium with refined copper slag added at a concentration of 22 g / L. However, when the concentration of refined copper slag exceeded 22 g / L, this microbial complex agent of ferrous oxide could not grow. It shows that the tolerance rate of this microbial complex agent to refined copper slag can reach 22 g / L.

[0063] Example 2 The microbial complex agent of ferrous oxide is composed of a Thiobacillus ferrooxidans microorganism and a Leptospirillum ferrooxidans microorganism. The strains used are the Thiobacillus ferrooxidans microorganism with the preservation number of ATCC23270 and the Leptospirillum ferrooxidans microorganism with the preservation number of ATCC29047. The cell number ratio of the Thiobacillus ferrooxidans microorganism to the Leptospirillum ferrooxidans microorganism is 1:1.

[0064] The microbial complex agent of ferrous oxide was inoculated into the 9K medium at an inoculation amount of 10% (v / v), and refined copper slag with a concentration of 10 g / L was added to the 9K medium. Leaching was carried out for 28 days under the conditions of a culture temperature of 35 °C, a shaker speed of 180 rpm, an initial Fe2+ concentration of 20 g / L, and a pH value of 2.25. Then, the conical flask was taken out, shaken to mix the precipitate evenly, and left to stand. After the precipitate was stable, 0.1 mL of the leaching solution was taken and diluted to 60 mL with distilled water. A kit (Guangdong Kai Microbial Technology Co., Ltd.) was used to measure the copper ions and nickel ions in the leaching solution.

[0065] Measurement results: The leaching rate of copper was 78.31%. The leaching rate of nickel was 60.22%.

[0066] Example 3 The microbial complex agent of ferrous oxide is composed of a Thiobacillus ferrooxidans microorganism and a Leptospirillum ferrooxidans microorganism. The strains used are the Thiobacillus ferrooxidans microorganism with the preservation number of ATCC23270 and the Leptospirillum ferrooxidans microorganism with the preservation number of ATCC29047. The cell number ratio of the Thiobacillus ferrooxidans microorganism to the Leptospirillum ferrooxidans microorganism is 1:2.

[0067] The microbial complex agent of ferrous oxide was inoculated into the 9K medium at an inoculation amount of 10% (v / v), and refined copper slag with a concentration of 10 g / L was added to the 9K medium. Leaching was carried out for 28 days under the conditions of a culture temperature of 35 °C, a shaker speed of 180 rpm, an initial Fe2+ concentration of 20 g / L, and a pH value of 2.25. Then, the conical flask was taken out, shaken to mix the precipitate evenly, and left to stand until the precipitate was stable. 0.1 mL of the leaching solution was taken and diluted to 60 mL with distilled water. A kit (Guangdong Kai Microbial Technology Co., Ltd.) was used to measure the copper ions and nickel ions in the leaching solution.

[0068] Determination results: The leaching rate of copper reached 80.64%. The leaching rate of nickel was 62.34%.

[0069] Example 3 The ferrous oxide microbial complex agent is composed of a Thiobacillus ferrooxidans microorganism and a Leptospirillum ferrooxidans microorganism. The strains used are the Thiobacillus ferrooxidans microorganism with the preservation number of ATCC23270 and the Leptospirillum ferrooxidans microorganism with the preservation number of ATCC29047. The cell number ratio of the Thiobacillus ferrooxidans microorganism to the Leptospirillum ferrooxidans microorganism is 1:2.

[0070] The ferrous oxide microbial complex agent was inoculated into the 9K medium at an inoculation amount of 10% (v / v), and refined copper slag with a concentration of 10 g / L was added to the 9K medium. Leaching was carried out for 28 days under the conditions of a culture temperature of 35 °C, a shaker speed of 180 rpm, an initial Fe2+ concentration of 20 g / L, and a pH value of 2.25. Then, the conical flask was taken out, shaken to mix the precipitate evenly, and after the precipitate was settled and stabilized, 0.1 mL of the leaching solution was diluted to 60 mL with distilled water, and a kit (Guangdong Kai Microbial Technology Co., Ltd.) was used to determine the copper ions and nickel ions in the leaching solution.

[0071] Determination results: The leaching rate of copper reached 80.64%. The leaching rate of nickel was 62.34%.

[0072] Example 4 The ferrous oxide microbial complex agent is composed of a Thiobacillus ferrooxidans microorganism and a Leptospirillum ferrooxidans microorganism. The strains used are the Thiobacillus ferrooxidans microorganism with the preservation number of ATCC23270 and the Leptospirillum ferrooxidans microorganism with the preservation number of ATCC29047. The cell number ratio of the Thiobacillus ferrooxidans microorganism to the Leptospirillum ferrooxidans microorganism is 1:3.

[0073] The ferrous oxide microbial complex agent was inoculated into the 9K medium at an inoculation amount of 10% (v / v), and refined copper slag with a concentration of 10 g / L was added to the 9K medium. Leaching was carried out for 28 days under the conditions of a culture temperature of 35 °C, a shaker speed of 180 rpm, an initial Fe2+ concentration of 20 g / L, and a pH value of 2.25. Then, the conical flask was taken out, shaken to mix the precipitate evenly, and after the precipitate was settled and stabilized, 0.1 mL of the leaching solution was diluted to 60 mL with distilled water, and a kit (Guangdong Kai Microbial Technology Co., Ltd.) was used to determine the copper ions and nickel ions in the leaching solution.

[0074] Determination results: The leaching rate of copper was 83.96%. The leaching rate of nickel was 63.81%.

[0075] Example 5 The ferrous oxide microbial composite agent is composed of a Thiobacillus ferrooxidans microorganism and a Leptospirillum ferrooxidans microorganism. The strains used are the Thiobacillus ferrooxidans microorganism with the preservation number of ATCC23270 and the Leptospirillum ferrooxidans microorganism with the preservation number of ATCC29047. The cell number ratio of the Thiobacillus ferrooxidans microorganism to the Leptospirillum ferrooxidans microorganism is 2:1.

[0076] The ferrous oxide microbial composite agent was inoculated into the 9K medium at an inoculation amount of 10% (v / v), and refined copper slag with a concentration of 10 g / L was added to the 9K medium. Leaching was carried out for 28 days under the conditions of a culture temperature of 35 °C, a shaker speed of 180 rpm, an initial Fe2+ concentration of 20 g / L, and a pH value of 2.25. Then, the conical flask was taken out, shaken to mix the precipitate evenly, and after the precipitate was settled and stabilized, 0.1 mL of the leaching solution was diluted to 60 mL with distilled water, and a test kit (Guangdong Kai Microbial Technology Co., Ltd.) was used to measure the copper ions and nickel ions in the leaching solution.

[0077] Measurement results: The leaching rate of copper was 78.97%. The leaching rate of nickel was 61.13%.

[0078] Example 6 The ferrous oxide microbial composite agent is composed of a Thiobacillus ferrooxidans microorganism and a Leptospirillum ferrooxidans microorganism. The strains used are the Thiobacillus ferrooxidans microorganism with the preservation number of ATCC23270 and the Leptospirillum ferrooxidans microorganism with the preservation number of ATCC29047. The cell number ratio of the Thiobacillus ferrooxidans microorganism containing the Leptospirillum ferrooxidans microorganism is 3:1.

[0079] The ferrous oxide microbial composite agent was inoculated into the 9K medium at an inoculation amount of 10% (v / v), and refined copper slag with a concentration of 10 g / L was added to the 9K medium. Leaching was carried out for 28 days under the conditions of a culture temperature of 35 °C, a shaker speed of 180 rpm, an initial Fe2+ concentration of 20 g / L, and a pH value of 2.25. Then, the conical flask was taken out, shaken to mix the precipitate evenly, and after the precipitate was settled and stabilized, 0.1 mL of the leaching solution was diluted to 60 mL with distilled water, and a test kit (Guangdong Kai Microbial Technology Co., Ltd.) was used to measure the copper ions and nickel ions in the leaching solution.

[0080] Measurement results: The leaching rate of copper was 79.53%. The leaching rate of nickel was 62.82%.

[0081] To better demonstrate this microbial composite agent and its uses, a comparative example was specifically added to highlight the effectiveness of the formulation of this microbial composite agent.

[0082] Comparative Example 1 The agent only contains one kind of Thiobacillus ferrooxidans microorganism.

[0083] 9K medium: 0.3 g of (NH4)2SO4, 0.1 g of KCl, 0.5 g of K2HPO4, 0.5 g of MgSO4·7H2O, 0.01 g of Ca(NO3)2, 30 g of FeSO4·7H2O, and 1000 mL of distilled water. Finally, adjust the pH value to 2.25 with 0.5 mol / L H2SO4.

[0084] Inoculate Thiobacillus ferrooxidans microorganisms (the strain used is Thiobacillus ferrooxidans with the preservation number of ATCC23270) into the 9K medium at an inoculation amount of 10% (v / v), and add refined copper slag to the 9K medium. Cultivate for 100 hours under the conditions of a cultivation temperature of 35°C, a shaker speed of 180 rpm, an initial Fe2+ concentration of 20 g / L, and a pH value of 2.25.

[0085] The concentrations of the added refined copper slag are 1 g / L, 5 g / L, 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, and 45 g / L respectively.

[0086] It was found that the microbial agent containing only one kind of Thiobacillus ferrooxidans microorganisms could still grow normally in the 9K medium with the concentration of added refined copper slag ranging from 0 to 20 g / L. However, when the concentration of refined copper slag exceeded 20 g / L, this iron-oxidizing microorganism could not grow. It shows that the tolerance rate of this microorganism to refined copper slag is 20 g / L.

[0087] Comparative Example 2 The microbial agent contains only one kind of Leptospirillum ferrooxidans microorganisms.

[0088] 9K medium: 0.3 g of (NH4)2SO4, 0.1 g of KCl, 0.5 g of K2HPO4, 0.5 g of MgSO4·7H2O, 0.01 g of Ca(NO3)2, 30 g of FeSO4·7H2O, and 1000 mL of distilled water. Finally, adjust the pH value to 2.25 with 0.5 mol / L H2SO4.

[0089] Inoculate Leptospirillum ferrooxidans microorganisms (the strain used is Leptospirillum ferrooxidans with the preservation number of ATCC29047) into the 9K medium at an inoculation amount of 10% (v / v), and add refined copper slag to the 9K medium. Cultivate for 100 hours under the conditions of a cultivation temperature of 35°C, a shaker speed of 180 rpm, an initial Fe2+ concentration of 20 g / L, and a pH value of 2.25.

[0090] The concentrations of the added refined copper slag are 1 g / L, 5 g / L, 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, and 45 g / L respectively.

[0091] It was found that the bacterial agent in this comparative example could still grow normally in the 9K medium with the concentration of refined copper slag added being 0 - 20 g / L. However, when the concentration of refined copper slag exceeded 20 g / L, this ferrous-iron-oxidizing microorganism could not grow. It shows that the tolerance rate of this microorganism to refined copper slag is 20 g / L.

[0092] Comparative Example 3 The bacterial agent only contains one type of Thiobacillus ferrooxidans microorganism.

[0093] 9K medium: 0.3 g of (NH4)2SO4, 0.1 g of KCl, 0.5 g of K2HPO4, 0.5 g of MgSO4·7H2O, 0.01 g of Ca(NO3)2, 20 g of FeSO4·7H2O, and 1000 mL of distilled water. Finally, adjust the pH value to 2.25 with 0.5 mol / L H2SO4.

[0094] Inoculate the bacterial agent (the strain used is Thiobacillus ferrooxidans microorganism with the preservation number of ATCC23270) into the 9K medium at an inoculation amount of 10% (v / v), and add refined copper slag with a concentration of 10 g / L to the 9K medium. Leach for 28 days under the conditions of a culture temperature of 35 °C, a shaker speed of 180 rpm, an initial Fe2+ concentration of 20 g / L, and a pH value of 2.25. Then take out the conical flask, shake it to mix the precipitate evenly, and after standing for the precipitate to be stable, take 0.1 mL of the leaching solution and dilute it to 60 mL with distilled water. Use a test kit (Guangdong Kai Microbial Technology Co., Ltd.) to measure the copper ions and nickel ions in the leaching solution.

[0095] The measured leaching rate of copper is 71.23%. The leaching rate of nickel is 54.44%.

[0096] Comparative Example 4 The bacterial agent only contains one type of Leptospirillum ferrooxidans microorganism.

[0097] 9K medium: 0.3 g of (NH4)2SO4, 0.1 g of KCl, 0.5 g of K2HPO4, 0.5 g of MgSO4·7H2O, 0.01 g of Ca(NO3)2, 20 g of FeSO4·7H2O, and 1000 mL of distilled water. Finally, adjust the pH value to 2.25 with 0.5 mol / L H2SO4.

[0098] The inoculum (the strain used is Leptospirillum ferrooxidans with the preservation number of ATCC29047) was inoculated into 9K medium at an inoculation amount of 10% (v / v), and refined copper slag with a concentration of 10 g / L was added to the 9K medium. The leaching was carried out for 28 days under the conditions of a culture temperature of 35 °C, a shaker speed of 180 rpm, an initial Fe2+ concentration of 20 g / L, and a pH value of 2.25. Then, the conical flask was taken out, shaken to mix the precipitate evenly, and after the precipitate was stabilized by standing, 0.1 mL of the leaching solution was diluted to 60 mL with distilled water, and a test kit (Guangdong Kai Microbial Technology Co., Ltd.) was used to measure the copper ions and nickel ions in the leaching solution.

[0099] Measurement results: The leaching rate of copper was 68.17%. The leaching rate of nickel was 59.89%.

[0100] Comparative Example 5 The Leptospirillum ferrooxidans in Example 2 was replaced with Leptospirillum ferrooxidans with the preservation number of CCTCC NO:M2017687 (a commercially available strain that can be purchased by the public from the China Center for Type Culture Collection (CCTCC)). The rest were the same as in Example 2.

[0101] Measurement results: The leaching rate of copper was 66.54%. The leaching rate of nickel was 57.83%.

[0102] Comparative Example 6 The Leptospirillum ferrooxidans in Example 2 was replaced with Leptospirillum ferrooxidans with the preservation number of CCTCC NO:M2014195, which is a commercially available strain that can be purchased by the public from the China Center for Type Culture Collection (CCTCC). The rest were the same as in Example 2.

[0103] Measurement results: The leaching rate of copper was 65.33%. The leaching rate of nickel was 54.27%.

[0104] Combining Example 1 with Comparative Example 1 and Comparative Example 2, it can be seen that the tolerance of this composite bacterium to refined copper slag has been significantly improved; combining Examples 2-6 with Comparative Example 3 and Comparative Example 4, it can be seen that the metal leaching effect of this microbial composite inoculum on refined copper slag has been significantly improved.

[0105] From the results of Comparative Example 5, Comparative Example 6 and Example 2, it can be seen that the composite inoculum prepared from the strain with a suitable preservation number selected in this application can further improve the metal leaching effect of refined copper slag.

[0106] The microbial complex bacterium agent described in the present invention has the advantages of environmental friendliness, strong tolerance, high adaptability, etc. The microbial complex bacterium agent described in the present invention can grow normally in a 9K medium with a refined copper slag concentration of 22 g / L. Therefore, the microbial complex bacterium agent of the present invention is applicable to the metal leaching of refined copper slag under different conditions. It contributes to the secondary utilization and recycling of refined copper slag metal resources and effectively protects the ecological environment of mining areas. At the same time, it achieves a win-win situation of obtaining economic benefits and environmental friendliness. Moreover, the microbial complex bacterium agent of the present invention is green and pollution-free and will not cause secondary pollution after leaching metals from refined copper slag. Therefore, the present invention is an ideal and efficient microbial complex bacterium agent in bio-metallurgy and can be widely applied to the field of bio-metallurgy.

[0107] In summary, the above are only the preferred embodiments of the present invention and do not impose any form of limitation on the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention and based on the technical essence of the present invention, any simple modification, equivalent replacement, and improvement made to the above embodiments shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A microbial composite agent of ferrous oxide, characterized in that, It includes Thiobacillus ferrooxidans microorganisms and Leptospirillum ferrooxidans microorganisms.

2. The microbial composite bactericide of ferrous oxide according to claim 1, wherein The Thiobacillus ferrooxidans microorganisms are selected from one or more of the following 44 microorganisms with deposit numbers; the 44 microorganisms with deposit numbers are respectively: CCTCC AB206199, CCTCC AB206200, CCTCC AB206201, CCTCC AB206202, CCTCC AB206203, CCTCC AB206204, CCTCC AB206205, CCTCC AB206206, CCTCC AB206207, CCTCC AB206208, CCTCC AB207053, CCTCC AB207054, CCTCC AB207055, CCTCC AB207056, CCTCC AB207057, CCTCC AB207058; ATCC13598D, ATCC53987, ATCC23270, ATCC53982, ATCC53983, ATCC14119, ATCC19859, ATCC33020, ATCC21834, ATCC13728, ATCC13661; DSM-2390, DSM-1931, DSM-14882, DSM-1928, DSM-1929, DSM-2389, DSM-700, DSM-2613, DSM-29444, DSM-9464, DSM-11477, DSM-24419, DSM-9465, DSM-1927, DSM-584, DSM-583, DSM-585.

3. The microbial complex bactericide of ferrous oxide according to claim 1, wherein The Leptospirillum ferrooxidans microorganisms are selected from one or more of the following 20 microorganisms with deposit numbers; the 20 microorganisms with deposit numbers are respectively: CCTCC AB206158, CCTCC AB206159, CCTCC AB206160, CCTCC AB206161, CCTCC AB206162, CCTCC AB206163, CCTCC AB206164, CCTCC AB207036, CCTCC AB207037, CCTCC AB207038; ATCC53992, ATCC29047, ATCC49879, ATCC49880, ATCC53993; DSM-2391, DSM-2705, DSM-1937, DSM-1929, DSM-1928.

4. The microbial composite agent of ferrous oxide according to any one of claims 1-3, characterized in that, The cell number ratio of Thiobacillus ferrooxidans microorganisms to Leptospirillum ferrooxidans microorganisms is (1 - 3):(3 - 1).

5. The microbial composite bactericide of ferrous oxide according to claim 4, wherein The cell number ratio of Thiobacillus ferrooxidans microorganisms to Leptospirillum ferrooxidans microorganisms is 1:1 or 1:2 or 1:3 or 2:1 or 3:

1.

6. Use of the ferrous oxide microbial complex agent according to any one of claims 1 - 5 in leaching metals.

7. A method for leaching metals using the ferrous oxide microbial complex bactericide according to any one of claims 1-5, characterized in that, It includes the following steps: inoculating the ferrous oxide microbial complex bactericide described in any one of claims 1-5 into a 9K medium, adding refined copper slag into the 9K medium, and performing fermentation culture.

8. The leaching method for metals according to claim 7, characterized in that, During the fermentation culture, the culture temperature is 35-45°C.

9. The method for leaching metal according to claim 7, characterized in that, In the 9K medium, the initial Fe2+ concentration is 10-30 g / L.

10. The metal leaching method according to any one of claims 7-9, characterized in that, The initial pH value of the medium is 2.0-3.0, the fermentation culture time is 20-30 days, and the shaker speed during the fermentation culture is 180 rpm.

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