Penicillium, composite ore leaching agent based on penicillium and ore leaching method of weathering crust elution-deposited rare earth ore

Abstract

The invention provides penicillium, a composite ore leaching agent based on the penicillium and an ore leaching method of weathering crust elution-deposited rare earth ore. The penicillium XT-1 is preserved in the China Center for Type Culture Collection (CCTCC), the preservation number is CCTCC NO: M20242845, the preservation number is CCTCC NO: M20242845, the preservation number is CCTCC NO: M20242845, and the preservation number is CCTCC NO: M20242845. The composite mineral leaching agent comprises a microbial metabolite of Penicillium sp. XT-1, ammonium sulfate and hydrochloric acid. In the rare earth leaching process, efficient selective extraction of rare earth elements is achieved through the biological-chemical synergistic effect, the problems that a traditional chemical leaching method is large in pollution and large in chemical reagent and energy consumption are solved, and the common problems that the mineral utilization rate is low and leaching is difficult in biological hydrometallurgy are solved.

Description

Technical Field

[0001] This invention relates to the field of mineral mining and processing technology, specifically to a Penicillium mold, a composite leaching agent based thereon, and a leaching method for weathered crust leached rare earth ores. Background Technology

[0002] Weathering crust leaching-type rare earth deposits (ion-adsorption rare earth deposits) were first discovered in Jiangxi Province, China, and are mainly distributed in eight provinces (Jiangxi, Guangdong, Fujian, Guangxi, Hainan, Hunan, Yunnan, and Zhejiang). These deposits are rich in medium and heavy rare earth elements, primarily adsorbed in kaolinite within the weathering layer. The rare earth elements occur mainly in aqueous solutions, ion-exchange states, iron-manganese oxide states, carbonate-bound states, strongly organic-bound states, and residual states. 50%–90% of the rare earth elements in these deposits exist in the ion-exchange state. They are characterized by large reserves, easy leaching, high quality, and low radioactivity, making them highly valuable economically. my country's medium and heavy rare earth reserves rank among the world's largest, and the optimization of its development and utilization technologies plays a crucial role in the global development of rare earth resources.

[0003] Currently, the main industrial method for extracting rare earth elements (REEs) is inorganic salt chemical leaching (ion exchange). Ammonium sulfate and magnesium sulfate are widely used as traditional and efficient leaching agents for the extraction of rare earth elements (REEs), but this has also brought serious ecological problems.

[0004] Microbial leaching technology mainly involves the physical or chemical reaction between microorganisms or their metabolites and rare earth minerals or secondary rare earth resources to leach rare earth elements. The microbial fermentation broth contains a variety of organic acids, which are more economical and resource-saving than purchasing industrial organic acids for leaching when directly applied to rare earth mining. This technology can achieve multiple goals such as saving resources, reducing energy consumption, and reducing environmental pollution, without causing secondary pollution to the environment. It is considered a potential technology for the development and utilization of rare earth resources.

[0005] Existing methods for bioleaching rare earth elements include one-step, two-step, and waste culture medium methods. Of these three methods, the one-step and two-step methods do not filter the microbial strains, allowing them to interact directly with the rare earth ore. The waste culture medium method involves the microbial strains interacting with the rare earth ore after producing sufficient metabolites. The one-step and two-step methods are contact bioleaching, while the waste culture medium method is non-contact bioleaching. In contact bioleaching, the growth and metabolic activities of microorganisms may be hindered due to the toxicity of rare earth ore or other toxic compounds, resulting in relatively poor stability. Non-contact bioleaching allows for the separate optimization of the production of the microbial leaching agent and the leaching steps, without considering the toxicity of certain elements to the microorganisms; however, the leaching rate of most microbial metabolites for rare earth elements is relatively low. Summary of the Invention

[0006] To address the problems existing in the background technology, the present invention provides a Penicillium mold, a composite leaching agent based on it, and a leaching method for weathered crust leached rare earth minerals. The metabolites of the Penicillium mold can selectively leach heavy rare earth elements (HREEs), the composite leaching agent has a high leaching rate, and can also reduce the amount of chemical reagents used and environmental pollution. It has many advantages such as simple process, low production cost, and environmental friendliness. The technical solution of the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, the present invention provides a Penicillium fungus, which is a Penicillium fungus ( Penicillium sp. XT-1, deposited at the China Center for Type Culture Collection, accession number: CCTCCNO:M20242845.

[0007] Secondly, the present invention provides a composite leaching agent comprising microbial metabolites and ammonium sulfate, wherein the microbial metabolites are the aforementioned Penicillium (…). Penicillium sp. ) XT-1 fermentation culture extract or its metabolites.

[0008] According to the above scheme, the pH value of the composite leaching agent is 4~5.

[0009] According to the above scheme, based on a 2% ammonium sulfate solution, the volume ratio of the microbial metabolites to the ammonium sulfate solution is 5:2 to 5:4.

[0010] According to the above scheme, the preparation method of the microbial metabolites is as follows: Penicillium (… Penicillium sp. XT-1 was cultured in a culture medium for 3-5 days, then filtered to obtain the microbial metabolites.

[0011] According to the above plan, Penicillium ( Penicillium sp. The culture medium for XT-1 was 1 / 5 LB medium, and the culture conditions were: temperature 28℃~32℃, rotation speed 150rpm~200rpm.

[0012] Secondly, the present invention provides the application of the above-mentioned composite leaching agent in the mining of weathered crust leaching rare earth deposits.

[0013] Thirdly, the present invention provides a leaching method for weathered crust leaching rare earth ore, using the above-mentioned composite leaching agent for leaching.

[0014] According to the above scheme, the composite leaching agent is directly mixed evenly with the weathered crust leaching rare earth ore powder for leaching.

[0015] According to the above scheme, the solid-liquid ratio of the weathered crust leaching rare earth ore to the composite leaching agent is 1:2 to 1:5, and the leaching time is 2 to 8 hours.

[0016] The principle of this invention is as follows: This invention uses Penicillium (…Penicillium sp. XT-1 metabolites, combined with chemical leaching agents ammonium sulfate and hydrochloric acid, were used to leach rare earth elements from weathered crust leached rare earth ores. Among these, Penicillium (… Penicillium sp. The metabolites of XT-1 are mainly benzene compounds, lipids and lipid molecules, and organic acids. These metabolites can leach ion-exchangeable rare earth elements into the solution. Combined with the ion exchange effect of ammonium sulfate, this reduces the amount of ammonium sulfate used in the rare earth leaching process and preferentially leaches heavy rare earth elements, improving the selectivity of rare earth resource separation. For the more difficult-to-dissolve iron-manganese oxide rare earth elements, chloride ions in hydrochloric acid can complex with these oxides, promoting their dissolution. Furthermore, the rare earth chlorides obtained from hydrochloric acid leaching are relatively chemically stable in solution and readily react with extractants and other chemical reagents, facilitating further separation and purification of rare earth elements.

[0017] The beneficial effects of this invention are: 1) This invention screened and obtained Penicillium ( Penicillium sp. XT-1, whose metabolites can leach rare earth elements, is used for leaching weathered crust leached rare earth ores; furthermore, its metabolites can selectively enrich heavy rare earth elements, increasing the LREEs / HREEs ratio from 35.26% to 39.37% after leaching. 2) Microbial metabolites are mixed with chemical reagents hydrochloric acid and ammonium sulfate as leaching agents for weathered crust leaching rare earth ores. Through bio-chemical synergy, the rare earth elements are extracted efficiently, resulting in high leaching efficiency. The microbial metabolites used can selectively leach heavy rare earth elements, and the hydrochloric acid used can leach iron and manganese oxide rare earth elements that are difficult to dissolve, which can further improve the rare earth leaching rate and the utilization rate of rare earth ores. 3) The microbial metabolites used have advantages such as low pollution and low cost. The raw materials used to cultivate microorganisms are green and environmentally friendly, which is conducive to the restoration and improvement of the ecological environment. It not only solves the problems of high pollution and large consumption of chemical reagents and energy in traditional chemical leaching methods, but also overcomes the problems of low mineral utilization and difficult extraction that are common in biohydrometallurgy. 4) The bio-chemical synergistic leaching method for weathered crust eluting rare earth ore prepared by the present invention has the advantages of simple equipment, easy operation and short cycle, which is conducive to industrial application. Attached Figure Description

[0018] Figure 1 Example 1 of the present invention is Penicillium ( Penicillium sp. Growth curve of XT-1 cultured in 1 / 5LB medium; Figure 2 Example 1 of the present invention is Penicillium ( Penicillium sp.) pH change of XT-1 cultured in 1 / 5LB medium; Figure 3 This invention relates to Penicillium ( ) under different pH conditions. Penicillium sp. )The leaching effect of XT-1 metabolites; Figure 4 This invention relates to Penicillium ( ) under different solid-liquid ratio conditions. Penicillium sp. )The leaching effect of XT-1 metabolites; Figure 5 The Penicillium of this invention ( Penicillium sp. The leaching effect of XT-1 metabolites and 2% ammonium sulfate under different ratios is shown in the figure. Figure 6 The Penicillium of this invention ( ) XT-1 metabolites and composite leaching agent leaching effect diagram at different leaching times; Penicillium sp. Penicillium ( Figure 7 )The leaching effect of XT-1 metabolites and composite leaching agent at different culture times; Penicillium sp. The leaching effect diagrams are shown when the composite leaching agents with different ratios are adjusted to different pH values. [[ID=并21]]Figure 8 The leaching effects of different leaching agents are shown in the diagram. Figure 9 For rare earth minerals in Penicillium ( Figure 10 The ratio of light and heavy rare earth elements before and after leaching of XT-1 metabolites. Detailed Implementation

[0019] The principles and features of the present invention are described below with reference to the accompanying drawings and specific embodiments. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0020] In this invention, the unit of liquid-solid ratio is mL / g, and grade represents the mass fraction of rare earth elements.

[0021] The experimental methods used in the following examples are as follows: (1) Isolation and screening of bacteria The target bacterial strain was screened from soil using a dilution-spreading method. First, multiple 10g samples of biocrusted soil were weighed and added to 250mL Erlenmeyer flasks containing 50mL, 100mL, and 200mL of sterile water, respectively. The mixtures were stirred with a glass rod, and the flasks were placed in a shaker and shaken at 180 rpm for 30 minutes. After standing, the sample mixtures were obtained. Next, the sample mixtures were diluted to 10... -1 10 -2 10 -3 10 -4 10-5 Five gradients were applied. Then, 100 μL of the liquid was pipetted onto the corresponding selective medium (beef extract peptone medium, Martin's medium, or modified Gao's No. 1 medium) and spread. The medium was incubated at 30°C, with three replicates for each gradient. Finally, strains with different morphologies were selected for three-zone streak culture to obtain purified strains. The composition or formulation of the selective medium is as follows: The formulation of beef extract peptone medium is as follows: beef extract 10 g / L, NaCl 5 g / L, peptone 10 g / L, agar 15 g / L; the formulation of Martin's medium is as follows: glucose 10.0 g / L, MgSO4·7H2O 0.5 g / L, peptone 5.0 g / L, K2HPO4 1 g / L, agar 20 g / L, with 3 ml of 1% streptomycin solution and 3.3 mL of 1% Bengal red solution added per liter of medium; the formulation of the modified Gao's No. 1 medium is as follows: soluble starch 20 g / L, KNO3 1 g / L, K2HPO4 0.5 g / L, MgSO4·7H2O 0.5 g / L, NaCl 0.05 g / L, FeSO4·7H2O 0.01 g / L, agar 20 g / L, with 3.3 mL of 3% potassium dichromate solution added per liter of medium, pH 7.2-7.4.

[0022] (2) Cultivation of rare earth mineral microbial strains The growth curves and pH changes of all isolated indigenous microorganisms were measured using 1 / 5 LB medium. First, an appropriate amount of 1 / 5 LB liquid medium was added to a 100 ml Erlenmeyer flask sterilized by autoclaving. A small amount of bacterial pellets was picked up with an inoculation loop and added to the 1 / 5 LB liquid medium for shake-induction culture. After two activations, 2% of the culture was added to a new sterile 100 ml Erlenmeyer flask, and 1 / 5 LB liquid medium and bacterial suspension were added to a final volume of 50 mL. The growth curves and pH changes were then measured under shake-induction conditions of 30℃ and 150 rpm. For bacteria and actinomycetes, the absorbance method was used. Every 2-4 hours, a small amount of bacterial suspension was taken and the OD600 nm value and pH value were measured using a spectrophotometer and pH meter, respectively. For fungi, the wet weight method was used. Multiple bottles of bacterial suspension were inoculated with equal amounts of the suspension. Every day, one bottle of suspension was taken, and the bacterial pellets were filtered through sterile gauze and weighed. Finally, after measuring the growth curves of different target strains, the strains were recultured at a 2% inoculum to reach the stationary phase, and microbial metabolites were obtained. The 1 / 5 LB medium consisted of 2 g / L tryptone, 1 g / L yeast extract, 2 g / L NaCl, and 20 g / L agar.

[0023] (3) Crude extraction of microbial metabolites from rare earth minerals The bacterial suspension in (1) above was crudely extracted to obtain microbial metabolites. The uniform bacterial solution was filtered to obtain microbial metabolites using a 0.22 μm needle filter membrane and a disposable sterile syringe. The bacterial solution that had grown into bacterial balls was filtered to obtain microbial metabolites after being folded into 4 layers of sterile degreased gauze.

[0024] (4) Treatment of weathered crust leaching type rare earth ore After sieving the weathered crust leaching rare earth ore at room temperature through a 20-mesh sieve, pile it into a small mound and divide it into four equal parts. Take one part for each experiment.

[0025] (5) Preparation of leaching agent Microbial metabolites: The crude microbial metabolites extracted in step (2) were quantified using 1 / 5LB medium with different pH values.

[0026] 2% Ammonium Sulfate: Dissolve solid ammonium sulfate in pure water and measure to 20 g / L.

[0027] 1:1 hydrochloric acid: Dilute concentrated hydrochloric acid with pure water at a ratio of 1:1.

[0028] (6) Leaching ore Weigh the weathered rare earth minerals and microbial metabolites from Longnan City, Jiangxi Province, processed in step (3), add them to a 100mL conical flask in different proportions, mix them evenly, and then place them in a constant temperature shaker at 30℃ and 150r / min for leaching. Then, take 0.75ml of the supernatant after leaching for 1h, 2h, 4h, 8h, and 24h into a centrifuge tube, centrifuge at 12000r / min for 1min, and take 0.5ml of the supernatant for titration.

[0029] (7) Titration EDTA and REE 3+ Since the stoichiometric ratio in the chemical reaction is 1:1, the rare earth content in the leachate can be analyzed by EDTA titration.

[0030] Prepare the following solutions respectively: Sulfosalicylic acid solution (100g / L): Add 5g of sulfosalicylic acid solid to a 50ml beaker, add a small amount of distilled water and stir to dissolve. Slowly transfer the solution to a 50mL volumetric flask, dilute to volume with distilled water, and shake well.

[0031] Hexamethylenetetramine buffer solution: Add 50g of solid hexamethylenetetramine to a 500mL beaker, dissolve it in 50mL of distilled water, then add 17.5mL of hydrochloric acid (1:1, i.e., a 1:1 volume ratio of concentrated hydrochloric acid to distilled water), and dilute to 250mL with distilled water.

[0032] Xylenol orange indicator (1g / L): Weigh 0.05g of xylenol orange into a 50mL beaker, dissolve it with a small amount of distilled water, transfer it to a 50mL volumetric flask, make up to volume with distilled water, shake well, and then transfer it to a brown indicator bottle.

[0033] Disodium ethylenediaminetetraacetate (relative molecular mass 372.24 g) (dilute EDTA: 0.0008 mol / L): Weigh 0.3 g of disodium ethylenediaminetetraacetate (EDTA) that has been dried at 80 °C for 2 hours into a 250 mL beaker using an electronic analytical balance. Dissolve the EDTA by heating and stirring with a small amount of water. After cooling, transfer the solution to a 1 L volumetric flask and dilute to volume with distilled water. Shake well.

[0034] In the preparation of the titrant, first add 10 mL of pure water and 0.5 mL of supernatant to a 100 mL conical flask. Then add a level spoonful of ascorbic acid and 2 mL of sulfosalicylic acid to mask impurity ions such as iron and aluminum. Adjust the pH of the solution to 5.0-5.5 with HCl and NH3·H2O. Then add 5 mL of hexamethylenetetramine as a buffer, add 2 drops of xylenol orange indicator, and titrate with 0.0008 mol / L EDTA standard solution until the solution changes from purple-red to bright yellow, which is the endpoint (one drop at a time with shaking). The final rare earth leaching efficiency is analyzed based on the rare earth content of 0.07% in the rare earth mine of Longnan City. The formula for the rare earth leaching rate is: REERecovery=(C EDTA *V EDTA ) / V0*MRE2O3*V m / M / 0.0007*100, where C EDTA EDTA concentration (mol / L), V EDTA V represents the volume of EDTA added (L), V0 represents the volume of the supernatant (mL), i.e., 0.5 mL, MRE2O3 is 137.56 g / mol, and V m M represents the total volume of metabolites (mL) and M represents the weight of rare earth minerals added during leaching (g).

[0035] The following multiple embodiments were carried out under different conditions in accordance with the above method.

[0036] Example 1: Isolation, screening and identification of microbial strains for rare earth ore leaching First, under conditions where a bacterial suspension was prepared by mixing rare earth biocrusts and sterile water at ratios of 1:5, 1:10, and 1:20, 16 morphologically and structurally distinct bacterial strains were isolated from rare earth biocrusts using three different culture media (beef extract peptone medium, Martin's medium, and a modified version of Gao's No. 1 medium). These strains were named according to the type of selective culture medium used and the pH value of the rare earth biocrusts. Next, after culturing the target strains to the stationary phase in 1 / 5 LB medium, metabolites were extracted for shake-flask leaching and EDTA titration experiments. 3g of rare earth mineral powder was weighed and added to a 100mL Erlenmeyer flask, along with 15ml of the target strain's metabolite. After mixing thoroughly, the mixture was placed in a constant-temperature shaker at 30℃ and 150r / min for leaching. Then, 0.75ml of the supernatant after 4 hours of leaching was transferred to a centrifuge tube and centrifuged at 12000r / min for 1 minute. 0.5ml of the supernatant was then used for EDTA titration, and the rare earth leaching rate of the leaching agent was calculated using the formula. Finally, by comparing the rare earth leaching rates of 16 strains under the same leaching conditions, it was found that fungus XT-1 had the highest leaching efficiency. XT-1 was identified as Penicillium (…). Penicillium sp. XT-1 was deposited on December 18, 2024, at the China Center for Type Culture Collection (address: Wuhan University, Luojia Mountain, Wuchang, Wuhan, Hubei Province), with accession number CCTCC NO:M 20242845.

[0037] Its growth curve and pH changes under 1 / 5 LB medium are as follows: Penicillium sp. and Figure 1 As shown.

[0038] Example 2 Penicillium ( Figure 2 Optimization of leaching conditions for XT-1 metabolites (1) Penicillium ( Penicillium sp. Leaching experiments of XT-1 metabolites under different pH conditions First, Penicillium ( Penicillium sp. After XT-1 culture reached the stationary phase (3 days), Penicillium was filtered out using sterile, defatted cotton gauze folded into 4 layers. Penicillium sp. XT-1 metabolites were detected by a pH meter as Penicillium ( The initial pH of XT-1 was 7.5 ± 0.2. Next, the pH of the metabolites was adjusted to 4, 4.5, 5, and 6 using HCl (1:1). Then, 10g of rare earth mineral powder was weighed and added to a 100mL Erlenmeyer flask along with 20ml of Penicillium mold. Penicillium sp.The XT-1 metabolites were mixed thoroughly and then placed in a constant-temperature shaker at 30℃ and 150 r / min for leaching. 0.75 ml of the supernatant after 4 hours of leaching was transferred to a centrifuge tube and centrifuged at 12000 r / min for 1 min. 0.5 ml of the supernatant was then used for EDTA titration. Finally, the rare earth leaching rate of the leaching agent was calculated using a formula. Penicillium sp. It can be seen that when the solid-liquid ratio is 1:2 and the bacterial weight is 1g, Penicillium ( Penicillium sp. The XT-1 metabolite showed the highest leaching efficiency, reaching 21.59%, at pH 4.5.

[0039] (2) Penicillium ( Figure 3 Leaching experiments of XT-1 metabolites under different solid-liquid ratios First, Penicillium ( Penicillium sp. After XT-1 culture reached the stationary phase (3 days), Penicillium was filtered out using sterile, defatted cotton gauze folded into 4 layers. Penicillium sp. XT-1 metabolites. Next, the pH of the metabolites was adjusted to 4.5 with HCl (1:1). Then, according to solid-liquid ratios of 1:1, 1:2, 1:3, 1:4, and 1:5, the corresponding weights of rare earth mineral powder were weighed and added to 100mL Erlenmeyer flasks, along with the corresponding volumes of Penicillium ( ). Penicillium sp. The XT-1 metabolites were mixed thoroughly and then placed in a constant-temperature shaker at 30℃ and 150 r / min for leaching. 0.75 ml of the supernatant after 4 hours of leaching was transferred to a centrifuge tube and centrifuged at 12000 r / min for 1 min. 0.5 ml of the supernatant was then used for EDTA titration. Finally, the rare earth leaching rate of the leaching agent was calculated using a formula. Penicillium sp. It can be seen that at pH 4.5 and a cell weight of 1g, Penicillium ( Penicillium sp. The XT-1 metabolite showed the highest leaching efficiency, reaching 30.18%, when the solid-liquid ratio was 1:4.

[0040] Example 2: Leaching Experiment with Composite Leaching Agent Penicillium ( Figure 4 The metabolites of XT-1 were mixed with ammonium sulfate to form a composite leaching agent for leaching experiments. (1) Effect of the ratio of composite leaching agent on leaching Penicillium ( Penicillium sp. Leaching experiments of XT-1 metabolites with 2% ammonium sulfate under different ratios. First, Penicillium ( Penicillium sp. After XT-1 culture reached the stationary phase (3 days), Penicillium was filtered out using sterile, defatted cotton gauze folded into 4 layers. Penicillium sp. XT-1 metabolites. Next, the pH of the metabolites was adjusted to 4.5 with HCl (1:1). Then, according to the Penicillium (Penicillium sp. XT-1 metabolites were used to prepare composite leaching agents with 2% ammonium sulfate solution in ratios of 5:1, 5:2, 5:3, 5:4, and 5:5. 5g of rare earth ore powder was weighed and added to a 100mL conical flask, followed by 20mL of the composite leaching agent. After mixing thoroughly, the mixture was placed in a constant-temperature shaker at 30℃ and 150r / min for leaching. 0.75ml of the supernatant after 4 hours of leaching was transferred to a centrifuge tube and centrifuged at 12000r / min for 1 minute. 0.5ml of the supernatant was then used for EDTA titration. Finally, the rare earth leaching rate of the leaching agent was calculated using a formula. Penicillium sp. It can be seen that at pH 4.5, a cell weight of 1g, and a solid-liquid ratio of 1:4, Penicillium (… Penicillium sp. The optimal leaching effect of XT-1 metabolite: 2% ammonium sulfate solution at a ratio of 5:4 is 94.75%, which can improve the leaching effect and reduce the amount of ammonium sulfate used.

[0041] (2) Effect of leaching time on leaching First, Penicillium ( Figure 5 After XT-1 culture reached the stationary phase (3 days), Penicillium was filtered out using sterile, defatted cotton gauze folded into 4 layers. [[ID=并48]]Penicillium sp. XT-1 metabolites were then used. Next, the pH of the metabolites was adjusted to 4.5 with HCl (1:1). A portion was used directly in the leaching experiment, and another portion was mixed with 2% ammonium sulfate at a ratio of 5:4 before further leaching. Then, 5g of rare earth ore powder was weighed and added to a 100mL conical flask along with 20mL of leaching agent. After mixing thoroughly, the flask was placed in a constant temperature shaker at 30℃ and 150r / min for leaching. For leaching times of 2h, 4h, and 8h, 0.75ml of the supernatant was transferred to a centrifuge tube and centrifuged at 12000r / min for 1min. 0.5ml of the supernatant was then used for EDTA titration. Finally, the rare earth leaching rate of the leaching agent was calculated using a formula. Penicillium sp. It can be seen that at pH 4.5, a cell weight of 1g, a solid-liquid ratio of 1:4, and the optimal concentration of Penicillium (…), the *Penicillium* species… Penicillium sp. XT-1 metabolites: The optimal leaching effect is achieved with a 2% ammonium sulfate solution at a ratio of 5:4 and a leaching time of 4 hours, with a pH of 4.5 for Penicillium ( Figure 6 The leaching efficiency of XT-1 metabolites can reach 32.45%, and the leaching efficiency of composite leaching agents can reach 94.08%.

[0042] (3) Effects of fungal metabolites and compound leaching agents on leaching effect under different culture times Penicillium ( Penicillium sp. Leaching experiments were conducted on the metabolites of XT-1 and the compound leaching agent at different culture times. First, Penicillium mold ( ) cultured for 1d, 2d, 3d, 4d, and 5d was used. Penicillium sp.The XT-1 metabolites were filtered out using sterile, degreased cotton gauze. Next, the pH of the metabolites was adjusted to 4.5 with HCl (1:1). A portion was used directly in the leaching experiment, and the remaining portion was mixed with 2% ammonium sulfate at a ratio of 5:4 before further leaching. Then, 5g of rare earth ore powder was weighed and added to a 100mL conical flask along with 20mL of leaching agent. After mixing thoroughly, the mixture was placed in a constant-temperature shaker at 30℃ and 150r / min for 4 hours. 0.75ml of the supernatant was transferred to a centrifuge tube and centrifuged at 12000r / min for 1 minute. 0.5ml of the supernatant was then used for EDTA titration. Finally, the rare earth leaching rate of the leaching agent was calculated using a formula. Penicillium sp. It can be seen that at pH 4.5, a cell weight of 1g, a solid-liquid ratio of 1:4, and the optimal concentration of Penicillium (…), the *Penicillium* species… Penicillium sp. XT-1 metabolites: 2% ammonium sulfate solution at a ratio of 5:4, leaching time of 4 hours, Penicillium ( Figure 7 XT-1 showed the best leaching efficiency after 3 days of cultivation, with metabolites reaching 30.18%, and the leaching efficiency of the composite leaching agent reached 94.75%.

[0043] (4) Effect of different pH values ​​on the leaching effect of composite leaching agent Different ratios of Penicillium ( Penicillium sp. Leaching experiments were conducted using XT-1 metabolites mixed with 2% ammonium sulfate and adjusted to different pH values. First, Penicillium (… Penicillium sp. After XT-1 culture reached the stationary phase (3 days), Penicillium was filtered out using sterile, defatted cotton gauze folded into 4 layers. Penicillium sp. XT-1 metabolites were then collected. Next, the metabolites were mixed with 2% ammonium sulfate in ratios of 5:1, 5:2, 5:3, 5:4, and 5:5 to prepare a composite solution. The pH of the composite solution was then adjusted to 4, 4.5, and 5 using HCl (1:1). Then, 5g of rare earth mineral powder was weighed and added to a 100mL conical flask along with 20mL of leaching agent. After mixing thoroughly, the flask was placed in a constant temperature shaker at 30℃ and 150r / min for 4 hours. 0.75ml of the supernatant was transferred to a centrifuge tube and centrifuged at 12000r / min for 1 minute. 0.5ml of the supernatant was then used for EDTA titration. Finally, the rare earth leaching rate of the leaching agent was calculated using the formula, and the results are as follows: Penicillium sp. As shown. Comparison Penicillium sp. , Figure 8 , Figure 3 , Figure 4It can be seen that there is no significant difference in leaching efficiency whether the pH of the metabolites is adjusted first before mixing with 2% ammonium sulfate, or the metabolites are mixed with 2% ammonium sulfate first and then the pH is adjusted. Considering cost, adjusting the pH of the metabolites first before mixing with 2% ammonium sulfate requires less HCl. Therefore, subsequent experiments will choose to adjust the pH of the metabolites first before mixing with 2% ammonium sulfate.

[0044] (5) Comparison of leaching effects of different leaching agents Penicillium under optimal leaching conditions ( Figure 5 A comparative experiment of XT-1 metabolites and compound leaching solutions with other leaching agents. First, Penicillium ( Figure 8 After XT-1 culture reached the stationary phase (3 days), Penicillium was filtered out using sterile, defatted cotton gauze folded into 4 layers. Penicillium sp. XT-1 metabolites. Next, the pH of the metabolites and 1 / 5 LB medium was adjusted to 4.5 with HCl (1:1). A portion of the metabolites and 1 / 5 LB medium was measured and mixed with 2% ammonium sulfate in a 5:4 ratio, and with 2% ammonium sulfate in a 1 / 5 LB medium, respectively, to prepare composite solutions. Then, 5g of rare earth ore powder was weighed and added to a 100mL conical flask along with 20mL of leaching agent. After mixing thoroughly, the flask was placed in a constant temperature shaker at 30℃ and 150r / min for 4 hours. 0.75ml of the supernatant was transferred to a centrifuge tube and centrifuged at 12000r / min for 1 minute. 0.5ml of the supernatant was then used for EDTA titration. Finally, the rare earth leaching rate of different leaching agents was calculated using a formula. Penicillium sp. It can be seen that at pH 4.5, a cell weight of 1g, a solid-liquid ratio of 1:4, and the optimal concentration of Penicillium (…), the *Penicillium* species… Penicillium sp. XT-1 metabolites: 2% ammonium sulfate solution at a ratio of 5:4, leaching time of 4 hours, Penicillium ( Figure 9 When XT-1 was cultured for 3 days, the leaching efficiency of metabolites was 32.45%, the leaching efficiency of the composite leaching agent of metabolites was 94.08%, the leaching efficiency of 1 / 5 LB medium solution at pH 4.5 was 9.56%, the leaching efficiency of the composite leaching solution in 1 / 5 LB medium was 76.73%, and the leaching efficiency of 2% ammonium sulfate was 92.57%. A comparison was made between 1 / 5 LB medium and Penicillium (…). Penicillium sp. The leaching efficiency of XT-1 metabolites indicates that Penicillium was cultured in 1 / 5 LB medium ( Penicillium sp. XT-1, Penicillium ( Penicillium sp. XT-1's metabolites do indeed contain substances that can improve rare earth leaching efficiency. (Compared to Penicillium...) Penicillium sp. The leaching efficiency of the composite leaching agent containing XT-1 metabolites and 2% ammonium sulfate shows that Penicillium ( Penicillium sp.The leaching efficiency of the composite leaching agent containing XT-1 metabolites is slightly higher than that of 2% ammonium sulfate, and the volume of 2% ammonium sulfate in the composite leaching agent is reduced by more than 50%, making it more environmentally friendly.

[0045] (6) Distribution of light and heavy rare earth elements in rare earth ore before and after leaching The proportions of light and heavy rare earth elements (LREEs / HREEs) in the rare earth slag were determined before and after leaching using the metabolites of XT-1. The rare earth ore was divided into two portions, one for leaching and the other for subsequent experiments. Before leaching (GZ-5): The rare earth ore was digested into a solution using a hot plate digestion experiment. Then, the content of each rare earth element in the solution was detected using ICP-MS, and the value of light rare earth element content divided by heavy rare earth element content (LREEs / HREEs) was calculated. After leaching (XT-1 metabolites): Rare earth ore was leached with XT-1 metabolites for 4 hours and then left to air dry outdoors. Next, a hot plate digestion experiment was used to digest the rare earth ore into a solution. Then, ICP-MS was used to detect the content of each rare earth element in the solution, and the ratio of the light rare earth element content to the heavy rare earth element content (LREEs / HREEs) was calculated. Compare the LREEs / HREEs ratios in rare earth ores before and after leaching with the metabolites of XT-1. Penicillium sp. Penicillium sp. Figure 10 It should be noted that there seems to be a duplicate "Figure 8" translation as "并21Figure 8" and "并48Penicillium sp." which might be errors in the original text or during the input process. You may want to check and correct if necessary. It can be seen that the LREEs / HREEs ratio in the rare earth ore before leaching is 35.26%, and the LREEs / HREEs ratio in the rare earth ore after leaching is 39.37%, indicating that the metabolites of XT-1 can selectively enrich heavy rare earth elements.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A Penicillium fungus, characterized in that, Penicillium ( Penicillium sp. XT-1, deposited at the China Center for Type Culture Collection, accession number: CCTCCNO:M20242845.

2. A composite lixivium characterized in that, comprising a microbial metabolite, ammonium sulfate and hydrochloric acid, the microbial metabolite being Penicillium sp. of claim 1 Penicillium sp. XT-1 extractive solution after fermentation culture or its metabolite.

3. The composite lixivium of claim 2, wherein, The pH value of the composite leaching agent is 4-5.

4. The composite lixivium of claim 2, wherein, The volume ratio of the microbial metabolite to the 2% ammonium sulfate solution is 5:2-5:

4.

5. The composite lixivium of claim 2, wherein, The method for preparing the microbial metabolite comprises the following steps: culturing Penicillium sp. Penicillium sp. XT-1 in a culture medium for 3-5 days, filtering, and obtaining the microbial metabolite.

6. The composite lixivium of claim 5, wherein, Penicillium ( Penicillium sp. The culture medium for XT-1 was 1 / 5 LB medium, and the culture conditions were: temperature 28℃~32℃, rotation speed 150rpm~200rpm.

7. The composite leaching agent according to any one of claims 1-6 is applied in the exploitation of weathering crust eluvium type rare earth ore.

8. A method for leaching a weathered crust-depositional rare earth ore, characterized by, The composite leaching agent according to any one of claims 1-6 is used for leaching.

9. The in-situ mining method of claim 8, wherein, The composite leaching agent is directly mixed with weathering crust eluvium type rare earth ore powder and leached.

10. The in-situ mining method of claim 9, wherein, The solid-liquid ratio of the weathering crust eluvium type rare earth ore to the composite leaching agent is 1:2-1:5, and the leaching time is 2-8 hours.

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