Rare earth extracting agent and application thereof

Abstract

The invention relates to the technical field of processing and utilization of microorganisms and mineral resources, in particular to a rare earth extracting agent and application thereof. The rare earth extracting agent provided by the invention comprises silicon-decomposing microorganisms, acid-producing microorganisms or fermentation products thereof which are screened from rare earth mines and rare earth wastes and have good symbiotic effect, high compatibility and high activity, so that the silicon-decomposing and acid-producing efficiency is further improved, and the rare earth element extracting efficiency is high. The rare earth leaching agent provided by the invention is simple and safe in component, and solves the problems of large chemical reagent dosage, high production cost, serious environmental pollution and the like in the rare earth waste chemical leaching process. The method is suitable for popularization.

Description

Technical Field

[0001] The invention relates to the technical field of microorganism and mineral resource processing and utilization, and in particular to a rare earth leaching agent and application thereof. Background Art

[0002] Rare earth elements include fifteen lanthanide elements and two metallic elements, scandium and yttrium. As an important strategic resource, they are widely used in cutting-edge research and high-tech industries and are known as "industrial gold". However, due to their uneven distribution and limited reserves, with the widespread application of rare earth elements in permanent magnetic materials, industrial catalysis and other fields, it has become necessary to extract rare earths from such secondary rare earth resources.

[0003] Traditional methods for recovering REEs from urban minerals mainly use physical and chemical leaching methods using strong acids and organic solvents. However, these methods are complex, energy-intensive, and cause significant environmental pollution. Therefore, there is an urgent need to develop a new clean and efficient leaching technology to ensure the leaching rate of rare earth elements while minimizing environmental pollution.

[0004] Bioleaching using microorganisms is an environmentally friendly alternative. This method mainly dissolves rare earth elements from solid matrices through organic acids (such as citric acid and lactic acid) or silicon-dissolving proteins, rare earth binding proteins, etc. produced by heterotrophic bacteria or fungi. However, commercial microorganisms such as yeast and Gluconobacter oxydans are inefficient and time-consuming to recover rare earth elements from discarded FCC catalysts. This is mainly because such microorganisms have poor tolerance to high concentrations of rare earth ions. In addition, the principles of promoting the dissolution of rare earth ions by various microorganisms are different. Some are carried out through organic acids or small molecules with rare earth binding functions, and some are carried out through the expression of silicon-dissolving proteins and rare earth binding proteins. Therefore, it is crucial to screen and cultivate powerful microorganisms from the microbial flora associated with rare earth mines and rare earth wastes, and to make them work together through a cocktail process to improve the bioenrichment efficiency of rare earth elements. However, there are few reports on bioleaching based on such microorganisms. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a rare earth leaching agent and its application. The present invention provides a rare earth leaching agent suitable for leaching rare earth elements by a cocktail method, which has simple ingredients, is safe, low cost and has high leaching efficiency.

[0006] The present invention provides a rare earth leaching agent, comprising:

[0007] Silicon-degrading microorganisms and / or fermentation broths thereof; and

[0008] The acidic reagent comprises at least one of an acid-producing microorganism, a fermentation liquid of the acid-producing microorganism and an organic acid.

[0009] Compared with the prior art, the silicon-degrading microorganisms and the acid-producing microorganisms provided by the present invention are selected from microbial flora that have good symbiotic effects with rare earth mines and rare earth wastes, have high compatibility and strong activity, and further improve the efficiency of silicon degrading and acid production, thereby obtaining more accurate technical effects.

[0010] In some embodiments, the silicon-decomposing microorganism includes Burkholderia cepacia with a deposit number of CGMCC NO.30396 and / or Priesteria gigantea with a deposit number of CGMCC NO.30398.

[0011] In some embodiments, the acid-producing microorganisms include Burkholderia cepacia and / or Aspergillus niger with a deposit number of CGMCC NO.30396;

[0012] The organic acids include pyruvic acid, lactic acid, acetic acid, formic acid, oxaloacetic acid, citric acid, gluconic acid, isocitric acid, α-ketoglutaric acid, succinic acid, succinyl coenzyme A, fumaric acid, malic acid, propionic acid, butyric acid, oxalic acid, tartaric acid, benzoic acid, azelaic acid, glycine, malonic acid, linoleic acid, stearic acid, palmitic acid, oleic acid, myristic acid, creatine, glutamic acid, aspartic acid, malic acid galactose, adipic acid, pimelic acid, carbolic acid, palmitoleic acid, sorbic acid, piperic acid, caffeic acid, ferulic acid, coniferous acid, phytic acid, gallic acid, nonanoic acid, caprylic acid, capric acid, undecanoic acid, dodecanoic acid, tetradecanoic acid, cyclopropanecarboxylic acid, taurine, color At least one of amino acid, phenylalanine, thiocyanic acid, palmitamide acid, linolenic acid, erucic acid, ursolic acid, lupine acid, arabinonic acid, gentisic acid, cysisic acid, punicic acid, carnosic acid, isovaleric acid, stearamide acid, edolic acid, maleic acid, cis-aconitic acid, hexafluoro acid, propargyl acid, celery acid, syringic acid, malva acid, azelaic acid, taranic acid, Cistanche acid, saponin acid, artemisinic acid, cynicic acid, saponin acid, oxalis acid, oxalis acid, typhaceous acid, poliporic acid, crab acid, pine acid, ambergris acid, cerotic acid, asarum acid, corn acid, hyacinth acid, rice germ acid, alkaloid acid, leopard skin acid, longan acid, salicylic acid and shikimic acid.

[0013] In some specific embodiments, the silicon-decomposing microorganism is Priesteria gigantea with a deposit number of CGMCC NO.30398;

[0014] The acid-producing microorganism is Aspergillus niger.

[0015] In other specific embodiments, the acid-producing microorganisms are Aspergillus niger and Burkholderia cepacia with a preservation number of CGMCC NO.30396.

[0016] It has been verified through experiments that the above-mentioned silicon-degrading microorganisms and acid-producing microorganisms have the best symbiotic effect with rare earth mines and rare earth wastes, the highest compatibility, and the strongest activity, and further achieve the highest efficiency of silicon degrading and acid production, thereby obtaining the most accurate technical effect.

[0017] In some embodiments, the organic acids include citric acid and gluconic acid.

[0018] In some embodiments, the method for preparing the fermentation broth of the silicon-degrading microorganism and the fermentation broth of the acid-producing microorganism comprises:

[0019] The silicon-dissolving microorganism or the acid-producing microorganism is obtained after activation culture, fermentation culture and centrifugation.

[0020] In some embodiments, the temperature of the activation culture is 25 to 35° C., the rotation speed of the activation culture is 180 to 220 rpm, and the time of the activation culture is 16 to 24 hours;

[0021] The fermentation culture comprises taking the activated cultured bacterial solution and the fermentation culture medium in a volume ratio of (0.5-2):100 and mixing them to a logarithmic phase, and the OD of the activated cultured bacterial solution is 600 The value is 0.8-1, the fermentation temperature is 25-35°C, and the fermentation speed is 180-220rpm;

[0022] The centrifugation includes centrifugation at 3000-9000 rpm for 0.5-60 min.

[0023] In some specific embodiments, the temperature of the activation culture is 30° C., the rotation speed of the activation culture is 200 rpm, and the time of the activation culture is 24 h;

[0024] The fermentation culture comprises taking the bacterial solution after the activation culture and the medium of the fermentation culture at a volume ratio of 1:100 and mixing and culturing them to the logarithmic phase, and the OD of the bacterial solution after the activation culture is 600 The value is 0.8 to 1, the fermentation temperature is 30°C, and the fermentation speed is 200 rpm;

[0025] The centrifugation includes centrifugation at 8000 rpm for 5 min.

[0026] In some embodiments, the acidic reagent is a fermentation broth of the acid-producing microorganism.

[0027] In some specific embodiments, the fermentation broth of the acid-producing microorganism is diluted before use, and the dilution comprises 2 vol% to 100 vol% of the fermentation broth of the acid-producing microorganism.

[0028] The invention provides application of the rare earth leaching agent in leaching rare earth elements.

[0029] The invention provides a method for extracting rare earth elements, which is obtained by mixing and leaching the rare earth leaching agent with rare earth ore.

[0030] In some embodiments, the steps include:

[0031] Step 1, taking the silicon-decomposing microorganism and / or its fermentation liquid and the rare earth mineral material, mixing and culturing, co-incubating, and centrifuging to obtain silicon-decomposing leaching liquid and the first leaching rare earth mineral material;

[0032] Step 2, taking the rare earth ore leached for the first time in step 1 and the acidic reagent, mixing and leaching to obtain an acid-generating leaching solution and a rare earth ore leached for the second time;

[0033] Step 3, combining the silicon-degrading leaching solution and the acid-generating leaching solution to obtain the rare earth element leaching solution;

[0034] Step 2 is performed once or repeated multiple times.

[0035] In some embodiments, in step 1,

[0036] The rare earth mineral material is waste FCC catalyst waste, the waste FCC catalyst waste includes 80wt% to 99.5wt% of faujasite and 0.1wt% to 10wt% of rare earth elements, and the OD of the silicon-decomposing microorganism is 600 The value is 0.6 to 1;

[0037] The culture medium of the mixed culture is LB liquid culture medium containing 60 g / L glucose, the volume ratio of the silicon-degrading microorganism to the culture medium is (0.1-10):100, and the mass volume ratio of the waste FCC catalyst waste to the culture medium is 1 g:(1-500) mL;

[0038] The co-incubation temperature is 25-35° C., the co-incubation speed is 120-280 rpm, the co-incubation time is 0.5-40 days, and the centrifugation includes centrifugation at 3000-9000 rpm for 0.5-60 min.

[0039] In some specific embodiments, in step 1,

[0040] The volume ratio of the silicon-decomposing microorganism to the culture medium is 1:100, and the mass volume ratio of the spent FCC catalyst waste to the culture medium is 1 g:50 mL;

[0041] The co-incubation temperature is 30° C., the co-incubation speed is 200 rpm, the co-incubation time is 2 to 4 days, and the centrifugation includes centrifugation at 8000 rpm for 5 minutes.

[0042] In some embodiments, in step 2,

[0043] The acidic reagent is a solution containing 1 vol% to 100 vol% of the fermentation liquid of the acid-producing microorganism;

[0044] The mass volume ratio of the rare earth ore leached for the first time to the acidic reagent is 1g: (1-500)mL;

[0045] The leaching temperature is 20-60° C., the leaching speed is 120-280 rpm, the leaching time is 0.5-40 days, and the centrifugation includes centrifugation at 3000-9000 rpm for 0.5-60 min.

[0046] In other embodiments, the fermentation broth of the acid-producing microorganism is concentrated once to obtain a concentrated solution, and the acidic reagent is a solution containing 0.05 vol% to 100 vol% of the concentrated solution.

[0047] In some specific embodiments, the acidic reagent is a solution containing 50 vol% of the fermentation broth of the acid-producing microorganism;

[0048] The acidic reagent is a solution containing 1 vol% to 100 vol% of the fermentation liquid of the acid-producing microorganism;

[0049] The mass volume ratio of the rare earth ore leached for the first time to the acidic reagent is 1g:50mL;

[0050] The leaching temperature is 30° C., the leaching speed is 200 rpm, the leaching time is 7 days, and the centrifugation includes centrifugation at 8000 rpm for 5 minutes.

[0051] In some specific embodiments, step 2 is performed twice, the acid-producing microorganism used in step 2 for the first time is Aspergillus niger, and the acid-producing microorganism used in step 2 for the second time is Burkholderia cepacia with a preservation number of CGMCC NO.30396.

[0052] Compared with the prior art, the beneficial effects of the present invention include:

[0053] 1. The rare earth leaching agent provided by the present invention includes silicon-decomposing microorganisms, acid-producing microorganisms or their fermentation products with good symbiotic effects selected from rare earth mines and rare earth wastes. Due to their good symbiotic effects with rare earth minerals, high compatibility and strong activity, the efficiency of silicon decomposition and acid production is further improved, and the efficiency of leaching rare earth elements is high;

[0054] 2. The rare earth leaching agent provided by the present invention has simple ingredients and is safe, and solves the problems of large amount of chemical reagents, high production cost, serious environmental pollution, etc. in the process of chemical leaching of rare earth waste. It is suitable for promotion and application.

[0055] Biological Deposit Description

[0056] Biomaterial: AHA-5, classification name: Burkholderia contaminans, deposited on April 22, 2024 at the General Microbiological Center of China Microbiological Culture Collection Administration, the address of the collection center is: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, the collection number is CGMCC No.30396;

[0057] Biological material: MER-2, classification name: Priestia megaterium, deposited on April 22, 2024 in the General Microbiology Center of China Culture Collection Administration. The address of the collection center is: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the collection number is CGMCC No.30398. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 The figure shows the theoretical leaching rate and the actual leaching rate predicted by the microorganisms based on the culture pH in Example 5;

[0059] Figure 2 A bar graph showing the leaching amount of rare earth elements in the spent FCC catalyst by the cocktail method in Example 7;

[0060] Figure 3 The leaching rate statistical results of Comparative Example 1 are shown. DETAILED DESCRIPTION

[0061] The present invention provides rare earth leaching agents and applications thereof. Those skilled in the art can refer to the contents of this article and appropriately improve the process parameters to achieve the same. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications of this article without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0062] The present invention adopts the following technical solution:

[0063] (1) Screening of silicon-degrading strains: The strains were screened using silicon-degrading culture medium solid plates and low-sugar leaching of FCC waste. Strains that can produce obvious silicon-degrading transparent rings on silicon-degrading culture medium solid plates were selected for subsequent screening. By culturing the above microorganisms in low-sugar culture medium, strains with better leaching effects than the predicted effects based on pH (marked with dotted lines) were selected for subsequent research, such as Burkholderia contaminans AHA-5 (CGMCC NO.30396), Priestia megaterium MER-2 (CGMCC NO.30398), etc.

[0064] (2) Screening of acid-producing strains: The strains were screened using solid plates of calcium carbonate culture medium. Burkholderia contaminans AHA-5 and Aspergillus niger, which can produce an obvious acid-producing transparent ring on solid plates of calcium carbonate culture medium, were selected for subsequent research.

[0065] (3) Screening of culture medium for microorganisms: The microorganisms were cultured in Luria-Bertani (LB) liquid medium, Potato Dextrose Broth (PDB) medium, and Tryptic Soy Broth (TSB) medium supplemented with 60 g / L glucose at 30°C and 200 rpm for 2-4 days. The culture fluid was extracted and the most suitable culture medium was screened using the screening methods in (1) and (2). Finally, Aspergillus niger was cultured in PDB medium, and AHA-5 and MER-2 were cultured in LB medium supplemented with 60 g / L glucose.

[0066] (4) Cultivation of microorganisms: AHA-5, MER-2, and Aspergillus niger were cultured using corresponding culture media at 30° C. and 200 rpm for 2-4 days.

[0067] (5) Disintegration of the silicon-oxygen structure of the spent FCC catalyst (the main component is 80 wt% to 99.5 wt% of faujasite zeolite, which contains 0.1-10% of rare earth elements) to promote the release of rare earth elements: Use microorganisms with silicon-degrading properties, such as AHA-5, MER-2, and the spent FCC catalyst for co-incubation at a solid-liquid ratio of 1:1-1:500 (the supernatant of the silicon-degrading microorganism culture can also be used for leaching, the steps are the same as the following step (6)), and culture at 30°C, 200 rpm for 0.5-40 days.

[0068] (6) Preparation of the extract: Use the bacterial suspension of the microorganism with acid-producing ability, such as AHA-5 or Aspergillus niger, prepared in step (2), centrifuge at 8000 rpm for 5 min, and collect the supernatant.

[0069] (7) Leaching the waste FCC catalyst treated with silicon-degrading microorganisms with the supernatant: After diluting the supernatant of the leachate in step (6) with ultrapure water (minimum supernatant content 2%), the original solution or the diluted solution is mixed with the waste FCC catalyst treated with silicon-degrading microorganisms in step (5) at a solid-liquid ratio of 1:1-1:500, and leaching is carried out at 30° C. and 200 rpm. After 0.5-40 days, a rare earth leachate is obtained. This process is repeated until the rare earth elements in the waste FCC catalyst are completely leached.

[0070] Leaching capacity detection: The rare earth element content and type in steps (5) and (7) were detected by ICP-OES and ICP-MS, and the leaching capacity of each step in the cocktail leaching was identified, and the total leaching rate was calculated.

[0071] The test materials used in the present invention are all common commercial products and can be purchased on the market.

[0072] Aspergillus niger ATCC16888 was purchased from Henan Industrial Microbial Engineering Technology Research Center;

[0073] Gluconobacter oxydans ATCC 19357 was purchased from Henan Industrial Microbial Engineering Technology Research Center

[0074] The present invention will be further described below in conjunction with the embodiments.

[0075] Example 1 Screening of microorganisms that dissolve poorly soluble silicates

[0076] Pick up a purified single microbial colony from the solid culture medium and place it in 4 mL LB liquid culture medium. Culture it overnight in a constant temperature shaking incubator at 30°C and 200 rpm. Take 2 μL of the bacterial liquid and drop it on a solid culture plate of silica-dissolving culture medium. After ten days of culture, observe and record the results. The appearance of a transparent ring is recorded as positive, indicating that the strain has the ability to dissolve insoluble silicates.

[0077] The results showed that 18 strains had good ability to dissolve insoluble silicates and were named Burkholderia, Priestia, Acetobacter 1-3, Burkholderia 1-2, Paraburkholderia1-5, Rhizobium and other 1-5 according to the genus.

[0078] Example 2 Screening of acid-producing microorganisms

[0079] Pick a purified single microbial colony from the solid culture medium and add it to 4 mL LB liquid culture medium. Culture it overnight in a constant temperature shaking incubator at 30°C and 200 rpm. Take 2 μL of the bacterial liquid and drop it on a solid culture plate of calcium carbonate culture medium. After ten days of culture, observe and record the results. The appearance of a transparent ring is recorded as positive, indicating that the strain has the ability to metabolize and produce acidic substances.

[0080] The results showed that Aspergillus niger and Burkholderia contaminans AHA-5 had good ability to dissolve insoluble carbonates.

[0081] Example 3 Screening of microbial culture medium

[0082] Pick the purified microbial colony from the solid culture medium and add it to 4mL liquid culture medium. The culture medium types include Luria-Bertani (LB) liquid culture medium, Potato Dextrose Broth (PDB) culture medium, and Tryptic Soy Broth (TSB) culture medium with 60g / L glucose added. Culture overnight in a constant temperature shaking shaker at 30℃ and 200rpm. Take 2μL of bacterial liquid and 2μL of culture supernatant and add them to the solid culture plates of silicon-dissolving culture medium and calcium carbonate culture medium respectively. After incubation for ten days, observe and record the results. Characterize the effect of culture medium type on microbial performance based on the radius of the transparent ring.

[0083] The results showed that Aspergillus niger was suitable for cultivation in PDB medium, while Burkholderiacontaminans AHA-5 and Priestia megaterium MER-2 were suitable for cultivation in LB medium supplemented with 60 g / L glucose.

[0084] Example 4: Disintegration of silicon-oxygen structure of spent FCC catalyst to promote release of rare earth elements

[0085] Pick a single colony of silicate-dissolving microorganisms from the solid culture medium into 4 mL LB liquid culture medium, and culture it overnight at 30°C and 200 rpm in a constant temperature shaking incubator as a seed liquid. Take a 1% volume ratio of seed liquid (OD600 value is 0.6-1) and inoculate it into LB liquid culture medium containing 60 g / L of glucose, which contains a waste FCC catalyst with a solid-liquid ratio of 1:50 (the main component is 80 wt% to 99.5 wt% of faujasite, which contains 0.1-10% of rare earth elements). Leach and culture for 7 days at 30°C and 200 rpm in a constant temperature shaking incubator. Centrifuge at 8000 rpm for 5 minutes, and collect the first leachate and precipitate respectively. Filter the supernatant with a 0.22 μm needle filter membrane and collect the filtrate. Use a nitric acid-perchloric acid (10:1) mixed acid system to digest on a 210 degree hot plate. After the solution becomes clear and transparent, it is diluted to a fixed volume until the target element content is 1ppb-10ppm, and the rare earth elements therein are quantitatively analyzed by ICP-OES and ICP-MS to obtain the first leaching rate.

[0086] The method for determining the content of rare earth elements in waste FCC catalysts includes: weighing a certain amount of waste FCC powder, and using a nitric acid-perchloric acid (10:1) mixed acid system to digest it on a 210-degree hot plate. After the solution becomes clear and transparent, dilute it to a fixed volume until the target element content is 1ppb-10ppm, and use ICP-OES and ICP-MS to perform quantitative analysis of the rare earth elements therein. The results show that the catalyst in this embodiment contains 0.82% La element and 0.72% Ce element. The content of rare earth elements in the waste FCC catalyst in this application is not limited to the elements and their contents provided in this embodiment. The rare earth leaching agent of this application has a good leaching effect on a variety of rare earth elements in other concentration ranges, but due to the large amount of experiments, they are not provided one by one for the time being.

[0087] Example 5 Study on the predictive leaching efficiency of microorganisms based on pH

[0088] The strains screened in Example 1 and Gluconobacter oxidans were cultured in the culture method of Example 4. After culture, the remaining catalyst was collected by centrifugation at 8000 rpm for 5 minutes, and digested on a 210°C hot plate using a nitric acid-perchloric acid (10:1) mixed acid system. The test results were compared with the original content to calculate the actual leaching rate. The theoretical leaching rate (after removing outliers, all data were regressed using the exponential method, that is, leaching rate = A*e^ (B*pH) +C). The data of theoretical leaching rate and actual leaching rate are statistically analyzed. The results are as follows Figure 1 And as shown in Table 1.

[0089] Table 1

[0090] Strain name pH Leaching rate Burkholderia 3.98 42.46393533 Priestia 5.5 31.88 Acetobacter-1 5.25 3.43 Acetobacter-2 3.57 34.9 Acetobacter-3 3.63 24.7 Burkholderia-1 3.94 37.79490459 Burkholderia-2 3.97 40.26912299 Gluconobacter 3.33 49.67065 Paraburkholderia-1 5.98 1.98 Paraburkholderia-2 5.71 0.08 Paraburkholderia-3 4.6 0.98 Paraburkholderia-4 3.99 9.53 Paraburkholderia-5 3.91 9.5 Rhizobium-1 4.84 4.254649893 Other-1 3.72 27.92 Other-2 4.35 3.74 Other-3 4.8 1.76 Other-4 4.71 2.662933166 Other-5 5.83 1.67

[0091] like Figure 1 As shown in Table 1, strain leaching effect screening, where the predicted leaching effect based on pH is marked with a dotted line, Priestia strains and Burkholderia strains have unexpectedly good leaching effects (wherein the theoretical value of Burkholderia is about 12.64%, the actual value is 40.18%, and the theoretical value of Priestia is about 1.02%, the actual value is 31.88%). In Example 2, it was also found that the Burkholderia strain has a good ability to dissolve carbonate.

[0092] The above two strains were deposited in the General Microbiology Center of China Microbiological Culture Collection Administration on April 22, 2024. The address of the collection center is: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The strain names and collection numbers are Burkholderia contaminans AHA-5 (CGMCC NO.30396) and Priestia megaterium MER-2 (CGMCC NO.30398), respectively.

[0093] Example 6 Preparation of Acidogenic Microbial Extract

[0094] Pick a single colony of the acid-producing microorganism from the solid culture medium and add it to 4 mL of the liquid culture medium corresponding to the microorganism, and culture it overnight in a constant temperature shaking incubator at 30°C and 200 rpm as the seed liquid. Take 1% of the seed liquid by volume and inoculate it into the liquid culture medium corresponding to the microorganism, and culture it in a constant temperature shaking incubator at 30°C and 200 rpm until the logarithmic phase. Centrifuge at 8000 rpm for 5 minutes to collect the supernatant.

[0095] Example 7: Supernatant Extraction of Rare Earth Elements from Spent FCC Catalyst Treated with Silicon-Degrading Microorganisms

[0096] The microbial culture supernatant solution or dilution (diluted with ultrapure water to a supernatant content of 50%) in Example 6 was added to the waste FCC catalyst precipitate in Experimental Example 4 (the rare earth element content in the waste FCC catalyst precipitate was determined by the rare earth element determination method in Example 4), mixed at a solid-liquid ratio of 1:50, and placed in a constant temperature shaking shaker at 30° C. and 200 rpm. After 2 days, a second leachate and a waste FCC catalyst precipitate were obtained, and the second leaching rate of rare earth elements in the second leachate was measured by the quantitative analysis method in Example 4.

[0097] The microbial culture supernatant solution or the diluted solution is again added to the waste FCC catalyst precipitate obtained in this example (the rare earth element determination method in Example 4 is used to determine the rare earth element content in the waste FCC catalyst precipitate), and the extraction is repeated once to obtain a third leachate, and the third leaching rate of rare earth elements in the third leachate is measured by the quantitative analysis method in Example 4.

[0098] The measurement results of Example 4 and Example 7 are as follows Figure 2 And as shown in Table 2.

[0099] The results showed that the total leaching efficiency of rare earth elements from spent FCC catalysts by the cocktail method was as high as 98.68% (MER-2 mixed with Aspergillus niger), which was higher than the total leaching efficiency of single strains of 79.96% (MER-2) and 79.26% (AHA-5).

[0100] Table 2

[0101] Silicon-dissolving strains Acid-producing strains First leaching rate Second leaching rate The third leaching rate Cumulative leaching rate AHA-5 Aspergillus niger 51.11 30.57 14.12 95.8 AHA-5 AHA-5 51.11 16.42 11.73 79.26 AHA-5 MER-2 51.11 12.49 11.4 75 MER-2 Aspergillus niger 46.92 35.89 15.88 98.68 MER-2 AHA-5 46.92 23.8 13.7 84.42 MER-2 MER-2 46.92 18.44 14.6 79.96

[0102] Example 8 Detection of the leaching ability of Aspergillus niger by ICP-MS

[0103] The microbial culture supernatant stock solution or dilution (diluted with ultrapure water to a supernatant content of 50%) in Example 5 was prepared using Aspergillus niger as the acid-producing strain, and 6 groups of experiments were set up, including:

[0104] Group 1, citric acid-gluconic acid mixed acid (mass ratio of citric acid to gluconic acid 1:3, the same below) was used as organic acid, and its addition amount was 3.5 g / L, which was equivalent to 50% of the acid content of the microbial culture fluid in Group 4 (the microbial culture fluid was quantitatively analyzed for organic acid using HClP);

[0105] Group 2, using citric acid-glucose acid mixture as organic acid, the addition amount was 7 g / L, which was equivalent to 100% of the acid content of the microbial culture solution in Group 4;

[0106] Group 3, using citric acid-glucose acid mixture as organic acid, the addition amount was 14 g / L, equivalent to 200% of the acid content of the microbial culture solution in Group 4;

[0107] Group 4, Example 5 microbial supernatant original fermentation broth concentration;

[0108] Group 5, Example 5 microbial supernatant and citric acid-glucose acid mixture 7 g / L as organic acid;

[0109] Group 6, 2 times the concentration of the microbial supernatant of Example 5;

[0110] Groups 1 to 6 were added to the waste FCC catalyst precipitate in Experimental Example 4, mixed at a solid-liquid ratio of 1:50, and placed in a constant temperature shaking table at 30°C and 200 rpm. After 2 days, a leachate was obtained, and the leaching rate is shown in Table 3.

[0111] Table 3

[0112] Grouping Leaching rate (%) 50% microbial acid production <![CDATA[19.326428 d ]]> 100% microbial acid production <![CDATA[27.686528 c ]]> 200% microbial acid production <![CDATA[41.630644 ab ]]> Microbial culture medium <![CDATA[36.577428 b ]]> Microbial culture fluid + 100% microbial acid production <![CDATA[46.827176 a ]]> 200% microbial culture fluid <![CDATA[49.651032 a ]]>

[0113] The results showed that the addition of additional organic acid to the microbial supernatant could improve the rare earth leaching performance of the microbial culture fluid, but at the same acid content, the total leaching rate was higher when the supernatant of acid-producing microorganisms was used.

[0114] Example 9: Supernatant added with complexing agent to compare leaching of rare earth elements in spent FCC catalyst treated with silicon-degrading microorganisms

[0115] In this example, the effect of the complexing agent on the leaching effect of rare earth elements was investigated, and the following groups (1) to (5) were set, specifically:

[0116] Group (1) and Group 2 in Example 8 added with 0.1 mM ligand (e.g., EDTA);

[0117] Group (2), Group 2 in Example 8 with the addition of 1 mM ligand (e.g., EDTA);

[0118] Group (3), Group 2 in Example 8, with the addition of 10 mM ligand (e.g., EDTA);

[0119] Group (4), Group 4 in Example 8;

[0120] Group (5), Group 4 in Example 8, added with 10 mM ligand (such as EDTA).

[0121] The above groups (1) to (5) were added to the waste FCC catalyst precipitate in Experimental Example 4, mixed at a solid-liquid ratio of 1:50, placed in a constant temperature shaking shaker at 30°C and 200rpm, and the leaching solution was obtained after 2 days. An artificially prepared organic acid solution with a concentration corresponding to that of the microbial culture solution was added with a complexing agent as a control, and the leaching rate is shown in Table 4.

[0122] Table 4

[0123] Grouping Leaching rate (%) 0.1mM EDTA <![CDATA[19.130032 c ]]> 1mM EDTA <![CDATA[28.042164 b ]]> 10mM EDTA <![CDATA[36.513732 a ]]> Microbial culture medium <![CDATA[36.577428 a ]]> Microbial culture medium + 10mM EDTA <![CDATA[36.211176 ab ]]>

[0124] The results show that the addition of additional ligands has no significant effect on the improvement of rare earth elements by microbial leaching, but has a significant effect on the leaching of rare earth elements by organic acids. The reason may be that substances with similar functions to ligands can be produced during the microbial fermentation process.

[0125] Example 10 Multiple rounds of supernatant leaching of rare earth elements from spent FCC catalyst treated with silicon-degrading microorganisms

[0126] MER-2 was used as the silicon-degrading strain for the first leaching, Aspergillus niger was used as the acid-producing strain for the second leaching, and AHA-5 was used as the strain for the third leaching (the third round of leaching experimental method was the same as in Example 7). The rare earth elements in the spent FCC catalyst treated with silicon-degrading microorganisms were leached using the method in Example 7. The leaching rates of the three rounds of leaching were calculated, and the first leaching rate was 46.92%, the second leaching rate was 35.89%, the third leaching rate was 17.18%, and the total leaching rate was 99.99%.

[0127] The results showed that over multiple cycles, the microorganisms were ultimately able to achieve a rare earth element leaching rate of more than 99.99%.

[0128] Embodiment 11

[0129] MER-2 was used as the silicon-degrading strain, and relevant research was conducted on the leaching culture time in Example 4. The leaching culture time was set to 1 to 40 days, and the first leaching rates were statistically shown in Table 5 below.

[0130] Table 5 Leaching effect at different times

[0131] Leaching culture time (days) First leaching rate (%) 1 14.11 2 30.43 3 33.32 4 35.57 5 37.21 6 41.72 7 46.92 14 47.55 28 47.69 40 48.32

[0132] The results showed that the first leaching rate showed an increasing trend with the extension of leaching time, but the growth trend slowed down after 7 days of leaching culture. For time considerations, setting the leaching culture time to 7 days was the best.

[0133] Example 12

[0134] MER-2 was used as the silicon-degrading strain, and relevant research was conducted on the solid-liquid ratio in Example 4. The solid-liquid ratio was set at 1:1 to 1:500, and the first leaching rates were statistically shown in Table 6 below.

[0135] Table 6 Leaching effect of different liquid-solid ratios

[0136] Liquid-to-solid ratio (liquid / solid, w / w) First leaching rate (%) 1 4.92 2 8.39 5 18.05 10 24.15 20 34.04 50 46.18 100 46.92 500 47.2

[0137] The results show that the first leaching rate increases with the increase of the volume proportion of the leaching solution, but the growth trend slows down after the solid-liquid ratio reaches 1:50. For cost considerations, setting the solid-liquid ratio to 1:50 is the best.

[0138] Embodiment 13

[0139] MER-2 was used as the silicon-dissolving strain and Aspergillus niger was used as the acid-producing strain. A related study was conducted on the dilution multiple of the microbial culture supernatant in Example 7. The microbial culture stock solution accounted for 1% to 100%, and the second leaching rates were statistically shown in Table 7 below.

[0140] Table 7 Leaching effect of different dilution multiples

[0141] Microbial culture stock solution ratio Second leaching rate (%) 1％ 36.38 5％ 53.33 10％ 78.98 20％ 87.21 50％ 94.24 100％ 97.03

[0142] The results show that the second leaching rate shows an increasing trend with the increase of the proportion of microbial culture solution, but the growth trend slows down after the proportion of microbial culture solution reaches 50%. For cost considerations, setting the proportion of microbial culture solution to 50% is the best.

[0143] Comparative Example 1

[0144] The use of existing industrial acid-producing microorganisms (such as Aspergillus niger and Gluconobacter oxydans) is less effective than the microorganisms mentioned in this study. Aspergillus niger, Gluconobacter oxydans, Burkholderia contaminans AHA-5, and Priestia megaterium MER-2 were cultured according to the culture method in Example 4. After culture, the remaining catalyst was collected by centrifugation at 8000 rpm for 5 minutes and digested using a nitric acid-perchloric acid (10:1) mixed acid system on a 210-degree hot plate. The test results were compared with the original content to calculate the leaching rate, which is shown in Figure 3 .

[0145] The results show that, compared with Aspergillus niger (extraction rate 35.42%), Gluconobacter oxydans (extraction rate 44.21%) and the microorganisms AHA-5 (extraction rate 68.46%) and MER-2 (extraction rate 65.08%) mentioned in this study, the strain provided by the present invention has higher single extraction efficiency and better effect.

[0146] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A rare earth leaching agent, characterized in that: include: Silicon-degrading microorganisms and / or fermentation broths thereof; and The acidic reagent comprises at least one of an acid-producing microorganism, a fermentation liquid of the acid-producing microorganism and an organic acid.

2. The rare earth leaching agent according to claim 1, characterized in that The silicon-degrading microorganisms include Burkholderia cepacia with a preservation number of CGMCC NO.30396 and / or Priesteria gigantea with a preservation number of CGMCC NO.30398.

3. The rare earth leaching agent according to claim 1 or 2, characterized in that The acid-producing microorganisms include Burkholderia cepacia with a deposit number of CGMCC NO.30396 and / or Aspergillus niger; The organic acids include pyruvic acid, lactic acid, acetic acid, formic acid, oxaloacetic acid, citric acid, gluconic acid, isocitric acid, α-ketoglutaric acid, succinic acid, succinyl coenzyme A, fumaric acid, malic acid, propionic acid, butyric acid, oxalic acid, tartaric acid, benzoic acid, azelaic acid, glycine, malonic acid, linoleic acid, stearic acid, palmitic acid, oleic acid, myristic acid, creatine, glutamic acid, aspartic acid, malic acid galactose, adipic acid, pimelic acid, carbolic acid, palmitoleic acid, sorbic acid, piperic acid, caffeic acid, ferulic acid, coniferous acid, phytic acid, gallic acid, nonanoic acid, caprylic acid, capric acid, undecanoic acid, dodecanoic acid, tetradecanoic acid, cyclopropanecarboxylic acid, taurine, color At least one of amino acid, phenylalanine, thiocyanic acid, palmitamide acid, linolenic acid, erucic acid, ursolic acid, lupine acid, arabinonic acid, gentisic acid, cysisic acid, punicic acid, carnosic acid, isovaleric acid, stearamide acid, edolic acid, maleic acid, cis-aconitic acid, hexafluoro acid, propargyl acid, celery acid, syringic acid, malva acid, azelaic acid, taranic acid, Cistanche acid, saponin acid, artemisinic acid, cynicic acid, saponin acid, oxalis acid, oxalis acid, typhaceous acid, poliporic acid, crab acid, pine acid, ambergris acid, cerotic acid, asarum acid, corn acid, hyacinth acid, rice germ acid, alkaloid acid, leopard skin acid, longan acid, salicylic acid and shikimic acid.

4. The rare earth leaching agent according to any one of claims 1 to 3, characterized in that The method for preparing the fermentation broth of the silicon-degrading microorganism and the fermentation broth of the acid-producing microorganism comprises: The silicon-dissolving microorganism or the acid-producing microorganism is obtained after activation culture, fermentation culture and centrifugation.

5. The rare earth leaching agent according to claim 4, characterized in that The temperature of the activation culture is 25 to 35° C., the rotation speed of the activation culture is 180 to 220 rpm, and the time of the activation culture is 16 to 24 hours; The fermentation culture comprises taking the activated cultured bacterial solution and the fermentation culture medium in a volume ratio of (0.5-2):100 and mixing them to a logarithmic phase, and the OD of the activated cultured bacterial solution is 600 The value is 0.8-1, the fermentation temperature is 25-35°C, and the fermentation speed is 180-220rpm; The centrifugation includes centrifugation at 3000-9000 rpm for 0.5-60 min.

6. Use of the rare earth leaching agent according to any one of claims 1 to 5 in leaching rare earth elements.

7. A method for extracting rare earth elements, characterized in that: The rare earth leaching agent according to any one of claims 1 to 5 is mixed with rare earth ore and leached to obtain the rare earth leaching agent.

8. The extraction method according to claim 7, characterized in that The steps include: Step 1, taking the silicon-decomposing microorganism and / or its fermentation liquid and the rare earth mineral material, mixing and culturing, co-incubating, and centrifuging to obtain silicon-decomposing leaching liquid and the first leaching rare earth mineral material; Step 2, taking the rare earth ore leached for the first time in step 1 and the acidic reagent, mixing and leaching to obtain an acid-generating leaching solution and a rare earth ore leached for the second time; Step 3, combining the silicon-degrading leaching solution and the acid-generating leaching solution to obtain the rare earth element leaching solution; Step 2 is performed once or repeated multiple times.

9. The extraction method according to claim 8, characterized in that In the step 1, The rare earth mineral material is waste FCC catalyst waste, the waste FCC catalyst waste includes 80wt% to 99.5wt% of faujasite and 0.1wt% to 10wt% of rare earth elements, and the OD of the silicon-decomposing microorganism is 600 The value is 0.6 to 1; The culture medium of the mixed culture is LB liquid culture medium containing 60 g / L glucose, the volume ratio of the silicon-degrading microorganism to the culture medium is (0.1-10):100, and the mass volume ratio of the waste FCC catalyst waste to the culture medium is 1 g:(1-500) mL; The co-incubation temperature is 25-35° C., the co-incubation speed is 120-280 rpm, the co-incubation time is 0.5-40 days, and the centrifugation includes centrifugation at 3000-9000 rpm for 0.5-60 min.

10. The extraction method according to claim 8 or 9, characterized in that In the step 2, The acidic reagent is a solution containing 1 vol% to 100 vol% of the fermentation liquid of the acid-producing microorganism; The mass volume ratio of the rare earth ore leached for the first time to the acidic reagent is 1g: (1-500)mL; The leaching temperature is 20-60° C., the leaching speed is 120-280 rpm, the leaching time is 0.5-40 days, and the centrifugation includes centrifugation at 3000-9000 rpm for 0.5-60 min.

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