CN112899184A

CN112899184A - Microbial agent for extracting copper from high-salt vulcanized electroplating sludge and extraction method

Info

Publication number: CN112899184A
Application number: CN202110053842.3A
Authority: CN
Inventors: 周洪波; 王玉光; 孙见行; 周文博
Original assignee: China Ocean Mineral Resources R & D Association (china's Ocean Affairs Administration); Central South University
Current assignee: China Ocean Mineral Resources R & D Association (china's Ocean Affairs Administration); Central South University
Priority date: 2021-01-15
Filing date: 2021-01-15
Publication date: 2021-06-04
Anticipated expiration: 2041-01-15
Also published as: CN112899184B

Abstract

The invention relates to a microbial agent for extracting copper from high-salt vulcanized electroplating sludge and an extraction method, wherein the microbial agent comprises bacillus Sulfobacillus acidophilus with a preservation number of CCTCC No: m2010203; sulfolobus metalens, with a collection number of JCM 9184; sulfobacillus thermosulfidobacterium thermophiles with the accession number of ATCC 19377; leptospirillum ferriphilum with a deposit number ATCC 29047. The invention not only solves the problem that the leaching microorganisms from the freshwater environment cannot tolerate sodium chloride, but also improves the growth speed and leaching rate of acidophilic microorganisms from the freshwater environment in the saline environment.

Description

Microbial agent for extracting copper from high-salt vulcanized electroplating sludge and extraction method

Technical Field

The invention belongs to the field of bioleaching and recycling of solid wastes, and particularly relates to a microbial agent for extracting copper from high-salt vulcanized electroplating sludge and an extraction method.

Background

The electroplating sludge refers to heavy metal-containing sludge waste generated after electroplating wastewater treatment in the electroplating wastewater treatment industry. Although the "final state substance" for the treatment of the electroplating wastewater is much smaller in quantity than the wastewater, the "final state substance" is classified as a seventeenth type of hazardous waste in the national hazardous waste list because various heavy metals such as Cu, Ni, Zn, etc. in the wastewater are transferred to sludge and the components thereof are very complicated. More than 1500 million tons of various types of electroplating sludge are newly added in China every year, and if the sludge with great harmfulness is not treated, the damage to the ecological environment is self-evident. On the other hand, since it is rich in various valuable metals and has a grade far higher than that of most natural minerals, the electroplating sludge is also called an unavailable and cheap renewable nonferrous metal resource. According to statistics, if valuable metal resources with extremely high grade in the electroplating sludge are not recycled, huge waste of about 10 ten thousand tons of metal resources is generated every year. Wherein the high-salt vulcanized electroplating sludge is a type of electroplating sludge which is difficult to treat, and is characterized in that sodium sulfide (Na) is added in the electroplating wastewater treatment process₂S) the electroplating sludge formed by settling various metal ions is difficult to be subjected to low-cost resource treatment due to the characteristics of high salt and high sulfide heavy metal.

The efficient leaching strategy is the first step for realizing resource recovery of high-content valuable metals in the electroplating sludge. The disposal of solid waste containing heavy metals by chemical methods (such as sulfuric acid, hydrochloric acid, ammonia water, etc.) and pyrogenic methods (calcination) is a common technical means in the past, but in recent years, due to the pressure of environmental protection and high cost input, these traditional means have been gradually not adopted or popularized. The biological wet leaching refers to that the biological characteristics of acidproof, heavy metal resistant, various metabolites produced and ferrous iron or/and sulfur oxidation ability of acidophilic microorganism are utilized, and the biological wet leaching is widely applied to the fields of metal leaching and recovery of low-grade ores and metal-containing solid wastes. Compared with the traditional chemical leaching, pyrogenic extraction and other methods, the biological method has the characteristics of low investment cost, less equipment requirement, good environmental benefit, high extraction efficiency and the like, and is widely applied to the field of low-grade mineral leaching. Meanwhile, a new resource recovery idea is provided for resource treatment of solid wastes which are difficult to treat, but unfortunately, although the traditional acidophilic micro ferrous iron or sulfur oxidizing microorganisms have good bioleaching effects on ores, partial types of solid wastes and the like, the traditional acidophilic micro ferrous iron or sulfur oxidizing microorganisms cannot easily exert the bioleaching function in a salt-containing environment, particularly a high-salt environment due to the fact that the traditional acidophilic micro ferrous iron or sulfur oxidizing microorganisms do not have the biological characteristics of salt tolerance. Therefore, no effective bioleaching method can be applied to bioleaching and resource recovery of high-salt vulcanized electroplating sludge at present.

Disclosure of Invention

The technical problem to be solved by the invention is to provide the microbial agent for extracting copper from the high-salt vulcanized electroplating sludge and the extraction method, so that the copper leaching rate is improved, the heavy metal content in leaching residues is reduced, and the toxicity of the heavy metal is reduced.

The invention relates to a microbial agent for extracting copper from high-salt vulcanized electroplating sludge, which comprises the following components,

the bacillus thioacidophilus Sulfobacillus acidophilus has a preservation number of CCTCC No: m2010203, with strain number TPY;

sulfolobus metalaxyl, accession number JCM 9184; JCM is short for the Japanese Collection of microorganisms.

Sulfobacillus thermosulfidobacterium thermophiles, with the accession number ATCC19377 and the strain number YN 22.

The end-tropic spirochete Leptospirillum ferriphilum has a deposit number of ATCC 29047 and a strain number of YSK.

The four bacteria are all deposited strains, can be purchased by corresponding depositing organizations, and do not need to be preserved again.

Preferably, the number ratio of the acidophilic thiobacillus, the metal sulfolobus, the thermotolerant thiobacillus and the siderophore spirillum is (1-4): 1-2): 1-3.

The invention provides a method for extracting copper from high-salt vulcanized electroplating sludge, which comprises the following steps,

culturing the above microbial agent to obtain bacteria with concentration of 1 × 10⁸cell/mL or more, and the oxidation-reduction potential is higher than 500 mV;

mixing the high-salt vulcanized electroplating sludge and the microorganism mixed bacteria liquid, controlling the pH value to be less than 3, stirring and leaching, carrying out solid-liquid separation to obtain a leaching solution, and recovering the metal copper in the leaching solution.

Preferably, the weight content of the high-salt vulcanized electroplating sludge in the reaction system after the high-salt vulcanized electroplating sludge is mixed with the microorganism mixed bacteria liquid is 15-25%.

Preferably, the pH is controlled to be 1.8 to 2.2.

Preferably, the stirring speed of the agitation leaching is 300-400 r/min, the temperature is 40-50 ℃, and preferably 50 ℃.

Preferably, the culture medium for culturing the microbial agent comprises, by weight, 2-5 parts of ammonium sulfate, 0.3-0.7 part of magnesium sulfate, 0.3-0.8 part of dipotassium hydrogen phosphate, 0.05-0.13 part of potassium chloride, 0.01-0.02 part of calcium nitrate, 15-25 parts of ferrous sulfate, 3-8 parts of elemental sulfur, 2-7 parts of sodium chloride and 1000 parts of water.

Preferably, the culture temperature for culturing the microbial agent is 38-50 ℃.

The method has the beneficial effects that salt-tolerant acidophilic microorganisms from a marine source and acidophilic iron/sulfur oxidizing microorganisms from a freshwater source are mixed to construct a flora containing the salt-tolerant acidophilic microorganisms from the marine source, and bacterial liquid of the flora is utilized to carry out bioleaching on the high-salt vulcanized electroplating sludge, so that a simple bioleaching technology capable of efficiently leaching the high-salt vulcanized electroplating sludge is provided, and resource utilization of the high-salt vulcanized electroplating sludge difficult to treat is realized.

The invention constructs a mixed flora by utilizing marine-derived Sulfobacillus acidophilus TPY, freshwater-derived Sulfolobus metllicus JCM 9184, Sulfobacillus thermolela YN22 and Leptospirillum ferriphilum YSK, and microorganisms from different sources of the flora can jointly grow in the same system, thereby realizing good compatibility.

In a flora co-culture system, the existence of salt-tolerant acidophilic microorganisms from marine sources can obviously improve the survival capability and activity of common acidophilic microorganisms in a high-salt environment, and improve the salt tolerance of the whole flora.

In a flora co-culture system containing acidophilic microorganisms from marine sources, the acidophilic microorganism flora can better exert the oxidizing capability of ferrous iron and sulfur in a salt-containing environment, and the bioleaching function of the whole flora is improved.

When the biological flora bacterial liquid is used as a leaching agent of the high-salt vulcanized electroplating sludge, the metal copper in the high-salt vulcanized electroplating sludge can be rapidly leached, and the copper leaching rate of the high-salt vulcanized electroplating sludge is improved.

The salt-tolerant acidophilic microbial flora bacteria liquid containing marine sources is used as a leaching agent, and compared with common (free of salt-tolerant bacteria) flora, the leaching effect of copper in high-salt vulcanized electroplated sludge is better.

Compared with a chemical leaching method, the method for leaching the electroplating sludge by using the microbial community bacterial liquid can obviously reduce the acid addition amount in the leaching process, reduce the generation of acid wastewater and reduce the wastewater treatment cost and the whole process cost.

The substrate of the invention is high-salt vulcanized electroplating sludge, the salt content is very high, generally, microorganisms from freshwater cannot grow well in the high-salt vulcanized electroplating sludge, and the invention selects and mixes acidophilic vulcanized bacillus and microorganisms from other freshwater to improve the biomass of other bacteria in a salt-containing culture system.

The leaching object of the invention is high-salt vulcanized electroplating sludge, and compared with common solid wastes, the electroplating sludge not only has very high salt content, but also has very high proportion (more than 85%) of sulfide metals. Therefore, acidophilic microorganisms of pure freshwater origin cannot grow and exert their bioleaching functions in such a high-salt environment. According to the invention, salt-tolerant acidophilic vulcanized bacillus from marine sources and efficient ferrous/sulfur-oxidized acidophilic microorganisms are selected and mixed and cultured according to the proportion in the range, and the obtained mixed biological flora improves the salt tolerance of the acidophilic microorganisms from fresh water sources and the activity of the acidophilic microorganisms in a high-salt environment on one hand, and the constructed biological flora can rapidly grow in the high-salt environment and keeps a stable microorganism proportion on the other hand, so that the ferrous/sulfur oxidization capability of the flora is better exerted, and the leaching effect on the high-salt vulcanized electroplating sludge is improved.

In the high-salt culture system, the biomass of non-salt-tolerant microbes in the salt-containing culture system can be increased in the presence of salt-tolerant acidophilic microbes from marine sources compared with the flora without salt-tolerant acidophilic microbes from marine sources.

By adopting the method, 95.3-99.92% of copper can be extracted from the copper-containing electroplating sludge which is difficult to treat and takes high-salt sulfide as a main component, the residual amount of copper in the leached dry slag is 64.31-185.1 mg/Kg, and the aims of efficiently treating the high-salt sulfide electroplating sludge and recovering metal resources are achieved.

By adopting the method, copper in the copper-containing electroplating sludge which is difficult to treat and takes high-salt sulfide as a main component can be efficiently recovered, the leaching residues can pass a toxicity leaching test, and the leaching residues cannot cause secondary pollution to the environment.

Compared with the traditional sulfuric acid leaching method, the utilization of the flora bacterial liquid as the leaching agent can not only obviously improve the effect of simultaneous feeding and discharging of the vulcanized electroplated sludge, but also enable the leached residues to pass a toxicity leaching test.

Drawings

FIG. 1 shows the growth of the bacteria with/without halotolerant bacteria in a saline medium.

FIG. 2 is the community composition of a population of halotolerant microbes of marine origin in a halotolerant medium.

Fig. 3 is a technical roadmap of the present invention.

FIG. 4 is a graph of the leached residues of the examples of the present invention (from left to right, as-leached residues of examples 1, 2 and 3, respectively).

FIG. 5 is a graph of comparative example leach residue according to the present invention (from left to right, as-is and comparative examples 1, 2, and 3, respectively).

FIG. 6 is a graph showing the comparison of the leaching effects of the comparative examples and examples of the present invention.

Detailed Description

In order to facilitate an understanding of the invention, the invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of the invention is not limited to the specific embodiments below.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

Example 1

High-salt vulcanized electroplating sludge produced in certain electroplating plant is used as raw material, and the biological flora constructed by the method is used for extracting metal copper. The method comprises the following steps:

1. the high-salt vulcanized electroplating sludge raw material is subjected to related measurement, the water content is 55.34%, the total copper content is 12.97%, the existing forms of copper are copper oxide, copper sulfide and copper sulfate, wherein more than 85% of copper exists in a sulfide form. As shown in table 1.

TABLE 1

2. Weighing 450g of natural base raw materials, adding the microbial flora enrichment constructed by the invention which meets the leaching requirement to ensure that the total leaching system reaches 2L, adjusting the pH value to be about 2.0 by using sulfuric acid, and stirring and leaching for 4 hours at the stirring speed of 350r/min at the temperature of 50 ℃.

The culture method of the microbial flora enrichment comprises the following steps of: sulfolobus metalllicusJCM 9184: sulfobacillus thermolora YN 22: the method is characterized in that a biological flora is constructed according to the proportion of 4:1.5:2:2.5 to carry out mixed culture, the culture medium is a basic salt culture medium added with an energy substrate and sodium chloride, and the components of the culture medium are as follows: ammonium sulfate: 3 Kg; magnesium sulfate: 0.4 Kg; dipotassium hydrogen phosphate: 0.45 Kg; potassium chloride: 0.08 Kg; calcium nitrate: 0.01Kg, ferrous sulfate: 20 Kg; elemental sulfur: 5 Kg; sodium chloride: 5 Kg; water; 1000L. Controlling the temperature of the culture system to be 45 ℃ and carrying out aeration culture. Until the microbial concentration of the constructed mixed flora reaches 1x10⁸The oxidation-reduction potential of the culture system is higher than 500mV, which can meet the leaching use requirement. The community composition of the obtained flora containing marine-derived halotolerant microorganisms in a salt-containing medium is shown in fig. 2.

3. And (3) carrying out solid-liquid separation on the leached materials in the step (2) by adopting a suction filtration mode to obtain leachate and leaching residues.

4. And (3) collecting the filter residue obtained in the step (3), adding 1.2L of clear water, stirring and washing at the normal temperature at a stirring speed of 300-350 r/min for 1h, performing solid-liquid separation in a suction filtration mode, and repeating the step for 1 time to obtain a washing liquid and washing residues.

5. And (3) drying a proper amount of washing slag generated in the step (4) in an oven at 105 ℃ to constant weight, determining that the copper residual quantity of the washing slag is 0.011 percent, the copper leaching rate of the electroplating sludge reaches more than 99.92 percent, and the washing slag passes a leaching toxicity test through inspection.

The above steps are shown in fig. 3.

Example 2

High-salt copper-containing vulcanized electroplating sludge generated by certain electroplating plants is used as a raw material, and the biological flora constructed by the method is adopted to extract metal copper.

1. The raw material is subjected to metal content measurement, and the main metal element is copper, and the copper content is 10.60%.

2. Weighing 50g of wet base raw materials, adding biological flora bacterial liquid meeting the leaching requirement to ensure that the total leaching system reaches 200mL, adjusting the pH to 2.0 by utilizing sulfuric acid, and stirring and leaching for 2h at the temperature of 40 ℃ at the stirring speed of 300 r/min. The enriched microbial population was cultured in the same manner as in example 1.

4. And (3) collecting the filter residue obtained in the step (3), adding 120mL of clear water, stirring and washing at a stirring speed of 300-350 r/min for 1h at normal temperature, performing solid-liquid separation in a suction filtration mode, and repeating the step for 1 time to obtain a washing liquid and washing residue.

5. And (3) drying a proper amount of washing slag generated in the step (4) in an oven at 105 ℃ to constant weight, and determining that the copper leaching rate of the electroplating sludge reaches 95.30%.

Example 3

1. The raw material was subjected to metal content measurement, and it was found that the main metal element was copper, and the copper content was 11.60%.

2. Weighing 25Kg of wet base raw material, adding the biological flora bacterial liquid meeting the leaching requirement to ensure that the total leaching system reaches 100L, adjusting the pH to 2.0, and stirring and leaching for 4 hours at the temperature of 45 ℃ at 300 r/min.

3. And (3) performing solid-liquid separation on the leached materials in the step (2) by using a filter press to obtain leachate and leaching residues.

4. And (3) collecting the filter residue obtained in the step (3), adding 70L of clear water, stirring and washing at the stirring speed of 300r/min for 1h at the temperature of 50 ℃, carrying out solid-liquid separation, and repeating the step for 1 time.

5. And (3) taking a proper amount of washing slag generated in the step (4) for metal residue measurement, measuring that the copper leaching rate of the electroplating sludge reaches 97.61%, and testing that the leaching slag passes a leaching toxicity test.

The copper residue in the leached residue in different examples is shown in Table 2.

TABLE 2 residual copper content in leached residues in different examples

As can be seen from the data in Table 2, the agitation leaching temperature of the present application has a very large influence on the residual amount of copper in the leached slag, the higher the temperature, the smaller the residual amount of copper.

Comparing the bioleaching method of the present application with the leaching effect of sulfuric acid leaching, it can be found that the bioleaching method of the present invention is significantly superior to sulfuric acid leaching in effect.

TABLE 3 comparison of heavy metal leaching toxicity test of leaching residues of different leaching methods

Comparative example 1

44.78g of copper produced by a certain electroplating plant was weighed out and extracted by the bioleaching method. The pH of the high-salt vulcanized plated sludge having a water content of 55.34% and a copper content of 12.97% was adjusted to about 2.0 with sulfuric acid, and a medium containing no microorganism was added thereto, the medium composition being the same as in example 1. Stirring and leaching for 4 hours at 50 ℃ and 350r/min, and carrying out solid-liquid separation. Other reaction conditions were the same as in example 1. And adding 1.2L of clear water into the filter residue, stirring and washing. The solid-liquid separation gave a copper leaching rate of 51.35%, which was significantly lower than that of example 1. The results not only indicate that the copper in the sulfide electroplating sludge is difficult to leach by the traditional dilute acid leaching (pH is 2.0), but also indicate that the invention can achieve better leaching effect which is the effect exerted by biological flora, but not the effect exerted by adding sodium chloride into the culture medium.

Comparative example 2

44.78g of copper produced by a certain electroplating plant was weighed out and extracted by the bioleaching method. Adjusting the pH of high-salt vulcanized electroplating sludge with water content of 55.34% and copper content of 12.97% to about 2.0 by using sulfuric acid, adding a bacterial liquid of iron/sulfur oxidation functional flora which does not contain Sulfobacillus acidophilus TPY, only consists of Sulfobacillus metallicus, Sulfobacillus thermoleanans YN22 and Leptospirillum ferophilum (the culture method of the enriched microbial flora is the same as that of example 1, but sodium chloride is not contained in the culture medium components), stirring and leaching at 50 ℃ for 4 hours at 350r/min, carrying out solid-liquid separation, and adding 1.2L of clear water into filter residues for stirring and washing. And (4) solid-liquid separation. Other reaction conditions were the same as in example 1. The copper leaching rate was 75.64%. The non-salt-tolerant microbial community which can not tolerate the high-salt environment can not achieve a good leaching effect on the high-salt vulcanized electroplating sludge. The reason is that after the non-salt-tolerant microbial community bacterial liquid is added into the leaching system containing the high-salt vulcanized electroplating sludge, the osmotic pressure inside and outside cells is imbalanced quickly due to no salt tolerance, so that a large amount of microorganisms die, the biological leaching function cannot be exerted, and a good leaching effect cannot be achieved.

Comparative example 3

44.78g of copper produced by a certain electroplating plant was weighed out and extracted by the bioleaching method. Adjusting the pH of high-salt vulcanized electroplating sludge with water content of 55.34% and copper content of 12.97% to about 2.0 by using sulfuric acid, only adding bacillus thioacidophilus Sulfobacillus acidophilus TPY bacterial liquid to 2L, stirring and leaching at 50 ℃ for 4h at 350r/min, carrying out solid-liquid separation, and adding 1.2L of clear water into filter residues. Washing the leached residue for 2 times, and performing solid-liquid separation. Other reaction conditions were the same as in example 1. The residual copper content was found to be 1.53%, and the copper leaching rate was found to be 88.20%. The result shows that the single salt-tolerant functional microbial liquid cannot efficiently leach the metal in the electroplating sludge. This is because although bacillus acidophilus has excellent salt tolerance and can grow in a high-salt environment, its ferrous/sulfur oxidizing ability (or bioleaching function) is difficult to compare with a mixed flora (generally, the function of a single bacterium is inferior to that of a flora of the same species), and thus a bioleaching effect as good as that of a mixed flora cannot be obtained.

Comparative example 4

44.78g of copper produced by a certain electroplating plant was weighed out and extracted by the bioleaching method. Adjusting the pH of high-salt vulcanized electroplating sludge with water content of 55.34% and copper content of 12.97% to about 2.0 by using sulfuric acid, adding a bacterial liquid of an iron/sulfur oxidation functional flora which does not contain Sulfobacillus metalllicis, only consists of Sulfobacillus acidophilus TPY, Sulfobacillus thermolerans YN22 and Leptospirillum ferriphilum YSK, stirring and leaching for 4 hours at 50 ℃ at 350r/min, and carrying out solid-liquid separation. Other reaction conditions were the same as in example 1. And adding 1.2L of clear water into the filter residue, stirring and washing. The solid-liquid separation was carried out, and the copper leaching rate was found to be 85.37%. It is shown that the non-salt-tolerant microbial flora cannot achieve a good leaching effect in a high-salt environment.

Comparing the leaching residue of examples 1 to 3 and comparative examples 1 to 3, as shown in FIGS. 4 to 5, FIG. 4 is a photograph taken after drying a sample, and FIG. 5 is a photograph taken without drying. The deeper the color, the higher the residual metal content, i.e., the poorer the treatment effect. The color of fig. 4 is lighter than that of fig. 5, indicating that the example is more effective than the comparative example.

Experimental example 1

The culture of halotolerant acidophilic bacteria flora with or without marine sources in a culture medium containing 0.5% of salt (NaCl) shows that compared with a halotolerant bacteria flora culture system (namely the microbial flora enrichment without acidophilic vulcanized bacillus in a comparative example 2), the growth condition of the flora in the salt-containing culture medium is shown in figure 1, and the growth condition of the microbial agent is better.

Claims

1. A microbial agent for extracting copper from high-salt vulcanized electroplating sludge is characterized by comprising,

the bacillus thioacidophilus Sulfobacillus acidophilus has a preservation number of CCTCC No: m2010203;

sulfolobus metalaxyl, accession number JCM 9184;

sulfobacillus thermosulfidobacterium thermophiles with the accession number of ATCC 19377;

leptospirillum ferriphilum with a deposit number ATCC 29047.

2. The microbial agent for extracting copper from high-salt vulcanized electroplating sludge as claimed in claim 1, wherein the ratio of the number of the bacillus acidophilus, the metal sulfolobus, the heat-resistant bacillus thiofidus and the leptospira ferrugineus is (1-4): 1-2): 1-3.

3. A method for extracting copper from high-salt vulcanized electroplating sludge is characterized by comprising the following steps,

culturing the microbial agent of claim 1 or 2 to a microbial concentration of1x10⁸cell/mL or more, and the oxidation-reduction potential is higher than 500 mV;

4. The method according to claim 3, wherein the weight content of the high-salt vulcanized electroplated sludge in the reaction system after the high-salt vulcanized electroplated sludge is mixed with the mixed microorganism bacteria is 15-25%.

5. The extraction process as claimed in claim 3, wherein the pH is controlled to 1.8-2.2.

6. The extraction process as claimed in claim 3, wherein the agitation speed of agitation leaching is 300 to 400r/min and the temperature is 40 to 50 ℃.

7. The method according to any one of claims 3 to 6, wherein the culture medium for culturing the microbial inoculum comprises, by weight, 2 to 5 parts of ammonium sulfate, 0.3 to 0.7 part of magnesium sulfate, 0.3 to 0.8 part of dipotassium hydrogen phosphate, 0.05 to 0.13 part of potassium chloride, 0.01 to 0.02 part of calcium nitrate, 15 to 25 parts of ferrous sulfate, 3 to 8 parts of elemental sulfur, 2 to 7 parts of sodium chloride, and 1000 parts of water.

8. The method according to any one of claims 3 to 6, wherein the culture temperature for culturing the microbial agent is 38 to 50 ℃.