Rare earth leaching agent and its application

Abstract

The present application relates to the technical field of microbial and mineral resource processing and utilization, in particular to a rare earth leaching agent and application thereof.The rare earth leaching agent provided by the present application comprises a silicon-removing microorganism, an acid-producing microorganism or a fermentation product thereof, which are screened from rare earth mines and rare earth waste materials and have a good symbiotic effect, are highly compatible, and have strong activity, thereby further improving the efficiency of silicon removal and acid production and the efficiency of leaching of rare earth elements.The rare earth leaching agent provided by the present application has simple components and is safe, and solves the problems of a large amount of chemical reagents, high production cost and serious environmental pollution in the chemical leaching process of rare earth waste materials, and is suitable for popularization and application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microbial and mineral resource processing and utilization, and particularly relates to a rare earth leaching agent and application thereof. BACKGROUND

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

[0003] The traditional method for recovering REEs from urban ores mainly uses physical and chemical leaching methods of strong acid and organic solvent. However, these methods are complex, high in energy consumption, and can cause significant environmental pollution. Therefore, it is urgent to develop a new clean and efficient ore leaching technology to ensure the leaching rate of rare earth elements while minimizing environmental pollution.

[0004] The bioleaching method using microorganisms is an environmentally friendly alternative. This method mainly dissolves rare earth elements from solid matrix through organic acids (such as citric acid and lactic acid) or silicate-lysing proteins, rare earth-binding proteins produced by heterotrophic bacteria or fungi. However, the efficiency of commercial microorganisms such as yeast and Gluconobacter oxydans in recovering rare earth elements from waste FCC catalysts is low and time-consuming. This is mainly because such microorganisms have poor tolerance to high concentrations of rare earth ions. In addition, the principles of each microorganism promoting the dissolution of rare earth ions are not the same, some through organic acids or small molecules with rare earth binding function, and some through the expression of silicate-lysing proteins and rare earth-binding proteins. Therefore, it is essential to screen and cultivate powerful microorganisms from the microbial flora associated with rare earth mines and rare earth waste, 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

[0005] Therefore, the technical problem to be solved by the present application is to provide a rare earth leaching agent and application thereof. The present application provides a rare earth leaching agent suitable for cocktail method leaching of rare earth elements, which is simple in composition, safe, low in cost and high in leaching efficiency.

[0006] The present application provides a rare earth leaching agent, which comprises:

[0007] silicate-lysing microorganisms and / or fermentation liquor thereof; and

[0008] an acidic agent, wherein the acidic agent comprises at least one of acid-producing microorganisms, fermentation liquor of the acid-producing microorganisms and organic acids.

[0009] Compared with the prior art, the desilication microorganism and the acid-producing microorganism are screened from a microbial flora that has a good symbiotic effect with rare earth mines and rare earth waste, have high compatibility and strong activity, and further improve the desilication and acid production efficiency, so that more accurate technical effects are obtained.

[0010] In some embodiments, the desilication microorganism includes Burkholderia cenocepacia with a preservation number of CGMCC NO. 30396 and / or Pristina megalli with a preservation number of CGMCC NO. 30398.

[0011] In some embodiments, the acid-producing microorganism includes Burkholderia cenocepacia with a preservation number of CGMCC NO. 30396 and / or Aspergillus niger.

[0012] The organic acid includes at least one of pyruvic acid, lactic acid, acetic acid, formic acid, oxalacetic acid, citric acid, gluconic acid, isocitric acid, alpha-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, galactaric acid, adipic acid, pimelic acid, anthracene acid, palmitoleic acid, sorbic acid, piperinic acid, caffeic acid, ferulic acid, coniferic acid, phytic acid, gallic acid, nonanoic acid, octanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tetradecanoic acid, cyclopropane carboxylic acid, taurine, tryptophan, phenylalanine, thiocyanic acid, palmitamide acid, linolenic acid, erucic acid, ursolic acid, lupinic acid, arabinic acid, gentisic acid, genipic acid, punicic acid, rosmarinic acid, taraxinic acid, gypsogenic acid, helianthic acid, echinocystic acid, eriocystic acid, sapindic acid, picrorhizic acid, typholic acid, polypodinic acid, chondrillidic acid, and at least one of salicylic acid and shikimic acid.

[0013] In some specific embodiments, the desilication microorganism is Pristina megalli with a preservation number of CGMCC NO. 30398.

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

[0015] In some specific embodiments, the acid-producing microorganism is Aspergillus niger and Burkholderia cenocepacia with a preservation number of CGMCC NO. 30396.

[0016] It is verified by experiments that the above-mentioned desiliconization microorganism and acid-producing microorganism have the best symbiotic effect, the highest compatibility and the strongest activity with rare earth mines and rare earth waste, and further obtain the highest desiliconization and acid production efficiency, so as to obtain the most accurate technical effect.

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

[0018] In some embodiments, the preparation method of the fermentation liquor of the desiliconization microorganism and the fermentation liquor of the acid-producing microorganism comprises:

[0019] The desiliconization 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 25-35℃, the rotation speed of the activation culture is 180-220rpm, and the time of the activation culture is 16-24h.

[0021] The fermentation culture comprises mixing the bacterial liquid after the activation culture and the culture medium for fermentation culture at a volume ratio of (0.5-2):100 to culture to the logarithmic phase, the OD value of the bacterial liquid after the activation culture is 0.8-1, the fermentation culture temperature is 25-35℃, and the rotation speed of the fermentation culture is 180-220rpm. 600

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

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

[0024] The fermentation culture comprises mixing the bacterial liquid after the activation culture and the culture medium for fermentation culture at a volume ratio of 1:100 to culture to the logarithmic phase, the OD value of the bacterial liquid after the activation culture is 0.8-1, the fermentation culture temperature is 30℃, and the rotation speed of the fermentation culture is 200rpm. 600

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

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

[0027] In some specific embodiments, the fermentation liquor of the acid-producing microorganism is used after dilution, and the dilution liquid comprises 2vol%-100vol% of the fermentation liquor of the acid-producing microorganism.

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

[0029] The application provides a rare earth element extraction method, which comprises the following steps: mixing and leaching of the rare earth leaching agent and rare earth ore materials.

[0030] In some embodiments, the method comprises the following steps:

[0031] Step 1: mixing and culturing the silicate-removing microorganism and / or fermentation liquor thereof with the rare earth ore materials, co-incubating, centrifuging to obtain a silicate-removing leaching liquor and first leached rare earth ore materials;

[0032] Step 2: mixing and leaching the first leached rare earth ore materials with the acid reagent to obtain an acid-producing leaching liquor and second leached rare earth ore materials;

[0033] Step 3: combining the silicate-removing leaching liquor and the acid-producing leaching liquor to obtain a rare earth element leaching liquor.

[0034] Step 2 is performed once or repeatedly.

[0035] In some embodiments, in step 1,

[0036] The rare earth ore materials are waste FCC catalyst waste materials, the waste FCC catalyst waste materials comprise 80wt%-99.5wt% of faujasite and 0.1wt%-10wt% of rare earth elements, and the OD 600 value of the silicate-removing microorganism is 0.6-1.

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

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

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

[0040] The volume ratio of the silicate-removing microorganism to the culture medium is 1:100, and the mass / volume ratio of the waste FCC catalyst waste materials to the culture medium is 1g:50mL.

[0041] The temperature of the co-incubation is 30℃, the rotation speed of the co-incubation is 200rpm, the time of the co-incubation is 2-4 days, and the centrifugation includes centrifugation at 8000rpm for 5min.

[0042] In some embodiments, the step 2 is performed twice, the acid-producing microorganism used in the first time of the step 2 is Aspergillus niger, and the acid-producing microorganism used in the second time of the step 2 is Burkholderia cenocepacia with the preservation number of CGMCC NO.30396.

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

[0044] The mass-volume ratio of the rare earth ore material to the acid reagent in the first leaching is 1g:(1-500)mL;

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

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

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

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

[0049] The mass-volume ratio of the rare earth ore material to the acid reagent in the first leaching is 1g:50mL;

[0050] The temperature of the leaching is 30℃, the rotation speed of the leaching is 200rpm, the time of the leaching is 7 days, and the centrifugation includes centrifugation at 8000rpm for 5min.

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

[0052] Compared with the prior art, the present application has the following beneficial effects:

[0053] 1. The rare earth leaching agent provided by the present application comprises a silicon-removing microorganism, an acid-producing microorganism or a fermentation product thereof, which is screened from rare earth mines and rare earth waste materials and has a good symbiotic effect, high compatibility and strong activity, thereby further improving the efficiency of silicon removal and acid production and the efficiency of leaching of rare earth elements.

[0054] 2. The rare earth leaching agent provided by the application has simple components and is safe, and solves problems such as large amount of chemical reagent, high production cost and serious environmental pollution in the chemical leaching process of rare earth waste materials, and is suitable for popularization and application.

[0055] BIOLOGICAL DEPOSIT DESCRIPTION

[0056] Biological material: AHA-5, classified as Burkholderia contaminans, preserved in the China General Microbiological Culture Collection Center on April 22, 2024, the address of the preservation center is No. 1, Beichen West Road, Yard 3, Institute of Microbiology, Chinese Academy of Sciences, Beijing Chaoyang District, and the preservation number is CGMCC No. 30396;

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

[0058] Figure 1 Theoretical leaching rate and actual leaching rate of microorganisms in Example 5 based on culture pH prediction result graph;

[0059] Figure 2 Column chart of leaching amount of rare earth elements in waste FCC catalyst in the cocktail method in Example 7;

[0060] Figure 3 Statistical results of leaching rate of Comparative Example 1. DETAILED DESCRIPTION

[0061] The present application provides a rare earth leaching agent and its application, and those skilled in the art can refer to the content herein to appropriately improve the process parameters. It should be particularly pointed out that all similar substitutions and changes are obvious to those skilled in the art, and they are all considered to be included in the present application. The method and application of the present application have been described by preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the method and application herein without departing from the content, spirit and scope of the present application, to realize and apply the present application technology.

[0062] The present application adopts the following technical solutions:

[0063] (1) Screening of silicate-dissolving strains: The strains were screened by using silicate-dissolving medium solid plate and low-sugar leaching of FCC waste. Strains that produced obvious silicate-dissolving transparent rings on silicate-dissolving medium solid plates were selected for subsequent screening. The above microorganisms were cultured in low-sugar medium, and strains with better leaching effect than the predicted effect based on pH (marked by a dashed line) were selected, such as Burkholderia contaminans AHA-5 (CGMCC NO. 30396), Priestia megaterium MER-2 (CGMCC NO. 30398), and the like for subsequent research.

[0064] (2) Screening of acid-producing strains: The strains were screened by using calcium carbonate medium solid plate. Burkholderia contaminans AHA-5, Aspergillus niger, and the like that produced obvious acid-producing transparent rings on calcium carbonate medium solid culture plates were selected for subsequent research.

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

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

[0067] (5) Dissolution of waste FCC catalyst (main component: 80wt%-99.5wt% of faujasite zeolite, containing 0.1-10% of rare earth elements) to promote the release of rare earth elements: Microorganisms with silicate-dissolving properties, such as AHA-5 and MER-2, were used to co-incubate with waste FCC catalyst at a solid-liquid ratio of 1:1-1:500 (or the supernatant of silicate-dissolving microbial culture was used for leaching, with the same steps as the following step (6)), and cultured at 30°C and 200 rpm for 0.5-40 days.

[0068] (6) Preparation of leaching solution: The supernatant of the bacterial suspension of microorganisms with acid-producing properties, such as AHA-5 and Aspergillus niger, was collected by centrifugation at 8000 rpm for 5 min.

[0069] (7) Leaching the spent FCC catalyst treated with silicon-degrading microorganisms using the supernatant: The supernatant of the leachate from step (6) is diluted with ultrapure water (minimum supernatant content 2%), and the original solution or the diluted solution is mixed with the spent FCC catalyst treated with silicon-degrading microorganisms in step (5) at a solid-liquid ratio of 1:1 to 1:500. The mixture is then leached at 30°C and 200 rpm to obtain a rare earth leachate after 0.5 to 40 days. This process is repeated until the rare earth elements in the spent 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 with reference to the embodiments.

[0075] Example 1 Screening of Microorganisms for Dissolving Insoluble Silicates

[0076] Pick a single colony of purified microorganisms from the solid culture medium and transfer it to 4 mL of 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 onto a solid culture plate of silica-dissolving 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] The purified single colony of microorganism was picked from the solid medium and inoculated into 4 mL liquid medium, including Luria-Bertani (LB) liquid medium with 60 g / L glucose, Potato Dextrose Broth (PDB) medium, and Tryptic Soy Broth (TSB) medium. The inoculum was incubated at 30 °C, 200 rpm overnight. 2 μL of the inoculum and 2 μL of the supernatant were dropped onto the solid medium of the dissolution medium and the calcium carbonate medium, respectively. After incubation for ten days, the results were observed and recorded. The presence of transparent ring indicated that the strain had the ability to metabolically produce acidic substances.

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

[0081] Example 3 Screening of microbial medium

[0082] The purified single colony of microorganism was picked from the solid medium and inoculated into 4 mL liquid medium, including Luria-Bertani (LB) liquid medium with 60 g / L glucose, Potato Dextrose Broth (PDB) medium, and Tryptic Soy Broth (TSB) medium. The inoculum was incubated at 30 °C, 200 rpm overnight. 2 μL of the inoculum and 2 μL of the supernatant were dropped onto the solid medium of the dissolution medium and the calcium carbonate medium, respectively. After incubation for ten days, the results were observed and recorded. The presence of transparent ring indicated that the strain had the ability to metabolically produce acidic substances.

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

[0084] Example 4 Dissolution of the silicon-oxygen structure of waste FCC catalyst to promote the release of rare earth elements

[0085] A single colony of the microorganism that dissolves the poorly soluble silicate was picked from the solid culture medium into 4 mL of LB liquid medium and incubated overnight at 30°C with 200 rpm constant temperature shaking in a shaking bed as a seed liquid. 1% of the seed liquid (OD600 value of 0.6-1) was inoculated into LB liquid medium containing 60 g / L of glucose, and the medium contained waste FCC catalyst (main component: 80 wt% to 99.5 wt% of zeolite with 0.1-10% of rare earth elements) at a solid-liquid ratio of 1:50. The leaching culture was carried out at 30°C with 200 rpm constant temperature shaking in a shaking bed for 7 days. 8000 rpm centrifugation was performed for 5 min, and the first leaching liquid and the precipitate were collected. The supernatant was filtered using a 0.22 μm needle filter, and the filtrate was collected. Digestion was performed using a nitric acid-perchloric acid (10:1) mixed acid system on a 210 degree heating plate. After the solution was clear and transparent, it was diluted to a constant volume, to a target element content of 1 ppb-10 ppm, so that the rare earth elements in ICP-OES and ICP-MS were quantitatively analyzed, and the first leaching rate was obtained.

[0086] The method for determining the content of rare earth elements in the waste FCC catalyst includes: weighing a quantitative waste FCC powder, and using a nitric acid-perchloric acid (10:1) mixed acid system to digest on a 210 degree heating plate. After the solution is clear and transparent, it is diluted to a constant volume, to a target element content of 1 ppb-10 ppm, so that the rare earth elements in ICP-OES and ICP-MS are quantitatively analyzed. The results show that the catalyst in this embodiment contains 0.82% of La element and 0.72% of 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 in this application has good leaching effect on a plurality of rare earth elements in other concentration ranges, but the experimental amount is too large, so it is not provided one by one.

[0087] Example 5 Microbial pH-based predicted leaching efficiency exploration

[0088] The strain screened in Example 1, i.e., Gluconobacter oxydans, was cultured according to the culture method of Example 4. After the culture, the remaining catalyst was collected by 8000 rpm centrifugation for 5 min, and digestion was performed using a nitric acid-perchloric acid (10:1) mixed acid system on a 210 degree heating plate. The actual leaching rate was calculated by comparing the test results with the original content. The theoretical leaching rate (after removing outliers, all data were regressed using the exponential method, i.e., leaching rate = A*e (B*pH) +C). The data of the theoretical leaching rate and the actual leaching rate are shown in Figure 1 and 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] As Figure 1 As shown in Table 1, strains were screened for leaching effect, with the predicted leaching effect based on pH marked with dotted lines, and the strains of the genus Priestia had unexpectedly good leaching effect (with the theoretical value of the genus Burkholderia being about 12.64%, and the actual value being 40.18%, and the theoretical value of the genus Priestia being about 1.02%, and the actual value being 31.88%). It was also found in Example 2 that the strain of the genus Burkholderia had good ability to dissolve carbonate.

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

[0093] Example 6 Preparation of leaching solution of acid-producing microorganism

[0094] Single colonies of acid-producing microorganisms were picked from solid culture medium into 4 mL of liquid medium corresponding to the microorganism, and incubated overnight at 30°C, 200 rpm in a constant temperature shaking incubator as seed liquid. 1% of the seed liquid by volume was inoculated into the liquid medium corresponding to the microorganism, and incubated at 30°C, 200 rpm in a constant temperature shaking incubator to the logarithmic phase. The supernatant was collected by centrifugation at 8000 rpm for 5 min.

[0095] Example 7 Rare earth elements in waste FCC catalyst treated by supernatant leaching of silicon-dissolving microorganisms

[0096] The supernatant of the microorganism culture in Example 6 was added to the waste FCC catalyst precipitate in Experimental Example 4 (the content of rare earth elements in the waste FCC catalyst precipitate was determined by the method for determining rare earth elements in Example 4), and mixed at a solid-liquid ratio of 1:50, and placed in a constant temperature shaking incubator at 30°C, 200 rpm. After 2 days, a second leaching solution and a waste FCC catalyst precipitate were obtained, and the second leaching rate of rare earth elements in the second leaching solution was measured by the quantitative analysis method of Example 4.

[0097] The supernatant of the microbial culture or the diluted supernatant was added to the waste FCC catalyst precipitate (the content of rare earth elements in the waste FCC catalyst precipitate was determined by the method for determining rare earth elements in Example 4) obtained in the embodiment again, and the third leaching liquid was obtained by repeating the extraction once. The third leaching rate of the rare earth elements in the third leaching liquid was measured by the quantitative analysis method in Example 4.

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

[0099] The results show that the total leaching efficiency of the rare earth elements in the waste FCC catalyst by the cocktail method is as high as 98.68% (MER-2 mixed with Aspergillus niger), which is higher than the total leaching of 79.96% (MER-2) and 79.26% (AHA-5) by a single strain.

[0100] Table 2

[0101] Silica leaching strain Acid producing strain First leaching rate Second leaching rate 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 capacity of Aspergillus niger by ICP-MS

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

[0104] Group 1: citric acid-glucuronic acid mixed acid (citric acid and glucuronic acid in a mass ratio of 1:3, the same below) was used as the organic acid, and the addition amount was 3.5 g / L, which was equivalent to 50% of the acid content of the microbial culture liquid in group 4 (the organic acid was quantitatively analyzed by Hclp);

[0105] Group 2: citric acid-glucuronic acid mixed acid was used as the organic acid, and the addition amount was 7 g / L, which was equivalent to 100% of the acid content of the microbial culture liquid in group 4;

[0106] Group 3: citric acid-glucuronic acid mixed acid was used as the organic acid, and the addition amount was 14 g / L, which was equivalent to 200% of the acid content of the microbial culture liquid in group 4;

[0107] Group 4: the original fermentation liquid of the microbial supernatant in Example 5;

[0108] Group 5: the microbial supernatant in Example 5 and citric acid-glucuronic acid mixed acid 7 g / L as the organic acid;

[0109] Group 6: twice the concentration of the microbial supernatant in Example 5;

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

[0111] Table 3

[0112] Group Leaching rate (%) 50% microbial acid production 19.326428 d ]]> 100% microbial acid production 27.686528 c ]]> 200% microbial acid production 41.630644 ab ]]> Microbial broth 36.577428 b ]]> Microbial broth + 100% microbial acid production 46.827176 a ]]> 200% microbial broth 49.65 10 32 a ]]

[0113] The results show that the addition of additional organic acids in the microbial supernatant can improve the leaching performance of rare earth elements in the microbial culture solution, but under the same acid content, the total leaching rate of the acid-producing microbial supernatant is higher.

[0114] Example 9 Effect of supernatant adding complexing agent on leaching of rare earth elements in waste FCC catalyst treated by desiliconization microorganisms

[0115] In this embodiment, the effect of complexing agent on the leaching of rare earth elements is explored, and the following groups (1)-(5) are set:

[0116] Group (1), 0.1 mM complexing agent (such as EDTA) is added to group 2 in Example 8;

[0117] Group (2), 1 mM complexing agent (such as EDTA) is added to group 2 in Example 8;

[0118] Group (3), 10 mM complexing agent (such as EDTA) is added to group 2 in Example 8;

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

[0120] Group (5), 10 mM complexing agent (such as EDTA) is added to group 4 in Example 8.

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

[0122] Table 4

[0123] Group Leaching rate (%) 0.1 mM EDTA 19.130032 c ]]> 1 mM EDTA 28.042164 b ]]> 10 mM EDTA 36.513732 a ]]> Microbial broth 36.577428 a ]]> Microbial broth + 10 mM EDTA 36.211176 ab ]]>

[0124] The results show that the addition of additional complexing agent has no significant effect on the leaching of rare earth elements by microorganisms, but has a significant effect on the leaching of rare earth elements by organic acids, and the reason may be that the microorganisms can produce substances similar to complexing agents during fermentation.

[0125] Example 10 Multiple rounds of supernatant leaching of rare earth elements in waste FCC catalyst treated by desiliconization microorganisms

[0126] The rare earth elements in the FCC catalyst treated by the silicon-removing microorganism in Example 7 were leached by using MER-2 as the first leaching strain, Aspergillus niger as the second leaching strain, and AHA-5 as the third leaching strain (the third leaching experiment was performed in the same manner as in Example 7). The leaching rates of the three leaching rounds were counted, respectively. 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 show that the microorganism can ultimately achieve a rare earth element leaching rate of more than 99.99% in multiple cycles.

[0128] Example 11

[0129] MER-2 was used as the silicon-removing strain, and a related study was conducted on the leaching culture time in Example 4. The leaching culture time was set to 1-40 days, and the first leaching rates were counted as shown in Table 5.

[0130] Table 5 Leaching effects 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 show that the first leaching rate shows a growth trend with the extension of the leaching time, but the growth trend slows down after the leaching culture for 7 days. Therefore, the leaching culture time of 7 days is the best.

[0133] Example 12

[0134] MER-2 was used as the silicon-removing strain, and a related study was conducted on the solid-liquid ratio in Example 4. The solid-liquid ratio was set to 1:1-1:500, and the first leaching rates were counted as shown in Table 6.

[0135] Table 6 Leaching effects at different liquid-solid ratios

[0136] Liquid-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 shows a growth trend with the increase of the leaching liquid volume ratio, but the growth trend slows down after the solid-liquid ratio is 1:50. Therefore, the solid-liquid ratio of 1:50 is the best.

[0138] Example 13

[0139] MER-2 was used as the silicon-removing 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%-100%, and the second leaching rates were counted as shown in Table 7.

[0140] Table 7 leaching effect of different dilution multiples

[0141] Microbial broth proportion 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 increases with the increase of the proportion of microbial culture stock solution, but the growth trend slows down after the proportion of microbial culture stock solution is 50%. Considering the cost, the proportion of microbial culture stock solution is set to 50% which is the best.

[0143] Comparative example 1

[0144] Using existing industrial acid-producing microorganisms (such as Aspergillus niger, Gluconobacter oxydans), compared with the microorganisms mentioned in this study, the effect is poor. Using Aspergillus niger, Gluconobacter oxydans and Burkholderia contaminans AHA-5, Priestia megaterium MER-2, according to the culture method in Example 4, after culture, centrifuge at 8000 rpm for 5 minutes to collect the remaining catalyst, use nitric acid-perchloric acid (10:1) mixed acid system on the heating plate at 210 degrees for digestion. Using the test results to compare the original content, the leaching rate is calculated and shown in Figure 3 .

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

[0146] The above is only a preferred embodiment of the present application, it should be noted that for ordinary skilled in the art, without departing from the principles of the present application, can make a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A rare earth leaching agent, characterized in that: include: Silicon-degrading microorganisms and / or fermentation broths thereof, wherein 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; and An acidic reagent, comprising: Fermentation broth of acid-producing microorganisms; or Fermentation broths of acid-producing microorganisms and organic acids; The acid-producing microorganisms include Burkholderia cepacia and / or Aspergillus niger ( Aspergillus niger ); The method for extracting rare earth elements using the rare earth leaching agent comprises the following steps: Step 1: Mixing the silicon-decomposing microorganism and / or its fermentation liquid with rare earth minerals, incubating them together, and centrifuging them to obtain silicon-decomposing leaching liquid and first leaching rare earth minerals; Step 2: taking the rare earth ore leached for the first time in step 1 and mixing with the acidic reagent, and leaching to obtain an acid-generating leachate and a rare earth ore leached for the second time; Step 3: combining the silicon-removing leachate and the acid-generating leachate to obtain the rare earth element leachate; Step 2 is performed once or repeated multiple times; The rare earth mineral material is waste FCC catalyst waste, the waste FCC catalyst waste includes 80wt%~99.5wt% of faujasite and 0.1wt%~10wt% of rare earth elements, the OD of the silicon-decomposing microorganism 600 The value is 0.6~1; The culture medium for the mixed culture is LB liquid culture medium containing 60 g / L glucose, the volume ratio of the silicon-decomposing microorganism to the culture medium is (0.1-10):100, and the mass volume ratio of the spent FCC catalyst waste to the culture medium is 1 g: (1-500) mL.

2. The rare earth leaching agent according to claim 1, characterized in that 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 CoA, 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, phenolic acid, palmitoleic acid, sorbic acid, piperic acid, caffeic acid, ferulic acid, coniferous acid, phytic acid, gallic acid, nonanoic acid, octanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tetradecanoic acid, cyclopropylcarboxylic acid, taurine, chromanoic acid, At least one of amino acid, phenylalanine, thiocyanic acid, palmitamide acid, linolenic acid, erucic acid, ursolic acid, lupine acid, arabinonic acid, gentisic acid, cytisic acid, punicic acid, carnosic acid, isovaleric acid, stearamide acid, edolic acid, maleic acid, cis-aconitic acid, hexafluoro acid, propargyl acid, celery acid, syringic acid, malvaceae acid, azelaic acid, taraxacic acid, rosticic acid, saponin acid, artemisinic acid, echinoic acid, saponin acid, oxalicylic acid, oxalicylic acid, typhaceous acid, poliporic acid, crab carboxylic acid, pinic acid, ambrosialic acid, cerotic acid, asarum acid, zeatic acid, hyacinthic acid, rice germ acid, alkaloid acid, leucophyllic acid, longan acid, salicylic acid and shikimic acid.

3. The rare earth leaching agent according to claim 1 or 2, characterized in that The preparation method of the fermentation broth of the silicon-decomposing microorganism and the fermentation broth of the acid-producing microorganism comprises: The silicon-decomposing microorganism or the acid-producing microorganism is obtained after activation culture, fermentation culture and centrifugation.

4. The rare earth leaching agent according to claim 3, characterized in that The activation culture temperature is 25-35° C., the activation culture speed is 180-220 rpm, and the activation culture time is 16-24 h. The fermentation culture comprises taking the activated cultured bacterial solution and the fermentation culture medium at a volume ratio of (0.5-2):100 and mixing them to the 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 180-220 rpm; The centrifugation includes centrifugation at 3000-9000 rpm for 0.5-60 min.

5. Use of the rare earth leaching agent according to any one of claims 1 to 4 in leaching rare earth elements.

6. A method for extracting rare earth elements, characterized in that: The rare earth leaching agent according to any one of claims 1 to 4 is mixed with rare earth ore and leached to obtain the product; The extraction method comprises the following steps: Step 1: Mixing the silicon-decomposing microorganism and / or its fermentation liquid with the rare earth mineral, culturing and co-incubating the mixture, and centrifuging the mixture to obtain a silicon-decomposing leaching liquid and a first leaching rare earth mineral; Step 2: taking the rare earth ore leached for the first time in step 1 and mixing with the acidic reagent, and leaching to obtain an acid-generating leachate and a rare earth ore leached for the second time; Step 3: combining the silicon-removing leachate and the acid-generating leachate to obtain the rare earth element leachate; Step 2 is performed once or repeated multiple times.

7. The extraction method according to claim 6, characterized in that In the step 1, The rare earth mineral material is waste FCC catalyst waste, the waste FCC catalyst waste includes 80wt%~99.5wt% of faujasite and 0.1wt%~10wt% of rare earth elements, the OD of the silicon-decomposing microorganism 600 The value is 0.6~1; The mixed culture medium is LB liquid medium containing 60 g / L glucose, the volume ratio of the silicon-decomposing microorganism to the medium is (0.1-10):100, and the mass volume ratio of the spent FCC catalyst waste to the 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.

8. The extraction method according to claim 6 or 7, characterized in that In the step 2, The acidic reagent is a solution containing 1 vol% to 100 vol% of the fermentation broth 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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