Thermophilic Thiobacilli Suitable for Ni and V Leaching

Abstract

The present invention relates to the field of environmental protection, and discloses Thermophilic Thiobacillus (Acidithiobacillus caldus) suitable for Ni and V leaching, wherein the preservation number of the Thermophilic Thiobacillus is CCTCC No: M2021708. The Thermophilic Thiobacillus (Acidithiobacillus caldus) described in the present invention can tolerate high doses of FCC spent catalysts and has a significant removal effect on metals (especially Ni and V) in FCC spent catalysts, and is suitable for biological leaching treatment of FCC spent catalysts.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection, and specifically relates to a thermophilic thiobacillus (Acidithiobacillus caldus), a bacterial agent, their applications in bio-metallurgy and bioleaching for removing metals from waste, and a method for bioleaching to remove metals from waste. Background Art

[0002] Catalytic fluidized catalytic cracking (FCC) catalysts are currently the most consumed refinery catalysts, accounting for 70% of the total usage of refinery catalysts. During the use of FCC catalysts, they will lose activity due to the deposition of coke and metal components such as nickel and vanadium in the feedstock oil, and the catalysts can no longer be used, becoming waste catalysts. Since FCC waste catalysts contain metal components with relatively high risks such as Ni, V, and Sb, they have always been considered to have a high environmental risk. Given the harmfulness of FCC waste catalysts, it is extremely important to carry out de-metallization and harmless treatment and disposal on them. Currently, the widely used methods for waste catalyst disposal and precious metal recovery are mainly two processes: pyrometallurgy and hydrometallurgy. However, both of these treatment methods have problems such as high energy consumption and serious secondary pollution.

[0003] Bioleaching technology is based on the metabolic activities of various bacteria to achieve the purpose of removing metals. Compared with traditional wet and pyrometallurgical processes, bioleaching has the advantages of environmental protection, low cost, simple operation and maintenance, mild treatment conditions required, and no hazardous waste discharge. However, the current attention and research on using bioleaching to treat FCC waste catalysts are very limited, and the leaching efficiency of metals is relatively low, which greatly limits the popularization and application of this technology. Moreover, since FCC waste catalysts are rich in various metal components with relatively high toxicity, the existing bioleaching bacterial strains have poor tolerance to FCC waste catalysts with relatively high concentrations. Generally, they can only produce a removal effect on 1%-5% of the waste catalysts, which greatly limits the application of bioleaching technology. It is hoped to screen microorganisms with high tolerance and high removal rate to improve the bioleaching efficiency of FCC waste catalysts. Summary of the Invention

[0004] The object of the present invention is to provide a thermophilic thiobacillus (Acidithiobacillus caldus), a bacterial agent, their applications in bio-metallurgy and bioleaching for removing metals from waste, and a method for bioleaching to remove metals from waste. This strain can tolerate high doses of FCC waste catalysts, significantly higher than the current 1%-5% addition amount of waste catalysts in strains, and has a significant removal effect on the metals in FCC waste catalysts with a 20% by weight addition amount.

[0005] To achieve the above object, on the one hand, the present invention provides a strain of Acidithiobacillus caldus, and the preservation number of the Acidithiobacillus caldus is CCTCC No: M 2021708.

[0006] On the second aspect of the present invention, a bacterial agent is provided, and the bacterial agent contains the above-mentioned Acidithiobacillus caldus.

[0007] On the third aspect of the present invention, the application of the above-mentioned Acidithiobacillus caldus and / or the above-mentioned bacterial agent in bioleaching is provided.

[0008] On the fourth aspect of the present invention, the application of the above-mentioned Acidithiobacillus caldus and / or the above-mentioned bacterial agent in bioleaching for removing metals from waste is provided.

[0009] On the fifth aspect of the present invention, a method for bioleaching to remove metals from waste is provided, and the method includes: contacting the above-mentioned Acidithiobacillus caldus and / or the above-mentioned bacterial agent with the waste.

[0010] The Acidithiobacillus caldus provided by the present invention can tolerate high doses (up to 40% by weight) of FCC waste catalyst, which is significantly higher than the addition amount of 1%-5% waste catalyst of the current strains, and has a significant removal effect on the metals in the FCC waste catalyst with an addition amount of 20% by weight.

[0011] The present invention provides an available strain for bioleaching to remove metals (especially Ni and V) from FCC waste catalyst, and it is expected to realize the industrial application of bioleaching to treat FCC waste catalyst.

[0012] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation part.

[0013] Biological preservation

[0014] The strain of the present invention is Acidithiobacillus caldus, and it was preserved in the China Center for Type Culture Collection (address: Luojia Mountain, Wuchang, Wuhan University, postal code: 430072) (the abbreviation of the preservation unit is CCTCC) on June 9, 2021, and the preservation number is CCTCC No: M 2021708. Specific implementation mode

[0015] The endpoints and any values disclosed in this text for ranges are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this text.

[0016] The first aspect of the present invention provides a strain of Acidithiobacillus caldus, and the preservation number of this Acidithiobacillus caldus is CCTCC No: M 2021708.

[0017] The above-mentioned Acidithiobacillus caldus was preserved in the China Center for Type Culture Collection on June 9, 2021 (address: Luojia Mountain, Wuchang, Wuhan University, postal code: 430072) (the abbreviation of the preservation unit is CCTCC), and the preservation number is CCTCC No: M 2021708.

[0018] The second aspect of the present invention provides a bacterial agent, and this bacterial agent contains the above-mentioned Acidithiobacillus caldus.

[0019] In the present invention, in the bacterial agent, the concentration of the above-mentioned Acidithiobacillus caldus is not particularly limited and can be specifically selected according to specific circumstances. For example, it can be 10 8 cfu / g or more.

[0020] In addition, according to different intended uses, the bacterial agent provided by the present invention can be prepared into different dosage forms and is added with corresponding excipients and other components that will not affect the activity of the above-mentioned Acidithiobacillus caldus. Specific selections are well-known to those skilled in the art, and the present invention will not elaborate in detail here.

[0021] The bacterial agent is preferably a liquid bacterial agent.

[0022] The preparation method of the bacterial agent can be a conventional preparation method in the art, such as that described in the fifth aspect.

[0023] The third aspect of the present invention provides the application of the above-mentioned Acidithiobacillus caldus and / or the above-mentioned bacterial agent in bioleaching.

[0024] The fourth aspect of the present invention provides the application of the above-mentioned Acidithiobacillus caldus and / or the above-mentioned bacterial agent in bioleaching for removing metals from waste materials.

[0025] The waste material is preferably a FCC waste catalyst.

[0026] The fifth aspect of the present invention provides a method for biolixiviating and removing metals from waste, and the method includes: contacting the thermophilic Thiobacillus described above and / or the bacterial agent described above with the waste.

[0027] Preferably, the thermophilic Thiobacillus contacts the waste in the form of a bacterial agent.

[0028] Preferably, the preparation method of the bacterial agent includes: inoculating the thermophilic Thiobacillus into a biolixiviation medium for amplification culture to obtain a seed liquid, and then inoculating the seed liquid into the biolixiviation medium for fermentation to obtain the bacterial agent.

[0029] In the present invention, the biolixiviation medium can be a medium conventionally used in the art. Preferably, the biolixiviation medium contains: (NH4)2SO4 2 - 3 g / L, KH2PO4 2 - 4 g / L, MgSO4·7H2O 0.3 - 0.7 g / L, CaCl2 0.2 - 0.3 g / L, FeSO4 0.005 - 0.02 g / L, and sulfur powder 8 - 15 g / L; the pH of the biolixiviation medium is 2.5 - 3.5.

[0030] Preferably, the conditions for the amplification culture include: the temperature is 40 - 45 °C, and the time is 48 - 96 h.

[0031] When the amplification culture is carried out in a shake flask, the rotation speed can be controlled at 100 - 150 rpm, preferably 120 - 135 rpm.

[0032] Preferably, the viable count of the thermophilic Thiobacillus in the seed liquid is 1×10 8 cfu / mL or more.

[0033] Preferably, the inoculation amount of the seed liquid is 1 - 10% by volume.

[0034] Preferably, the conditions for the fermentation include: the temperature is 40 - 45 °C, the time is 24 - 120 h; the ventilation rate is 0.05 - 0.2 vvm. The stirring rotation speed during the fermentation process is determined according to the volume of the fermenter, and those skilled in the art can adjust it according to the actual situation.

[0035] Preferably, the viable count of the thermophilic Thiobacillus in the bacterial agent is 10 8 cfu / mL or more.

[0036] In the present invention, the waste can be any waste containing metals, preferably FCC spent catalyst.

[0037] The addition amount of the FCC spent catalyst can be selected within a relatively wide range. Preferably, compared with 1 L of the fermentation broth, the addition amount of the FCC spent catalyst is 150 - 200 g.

[0038] Preferably, the conditions for the contact include: a temperature of 40-45 °C and a time of 5-7 days.

[0039] The present invention will be described in detail below through examples.

[0040] In the following examples, unless otherwise specified, the reagents and materials used are all commercially available.

[0041] Preparation method of biological leaching medium: Each 1000 mL of distilled water contains 2 g of (NH4)2SO4, 3 g of KH2PO4, 0.5 g of MgSO4·7H2O, 0.01 g of FeSO4·7H2O, 0.25 g of CaCl2·2H2O. The pH is adjusted to 3.0 with 2 mol·L -1 sulfuric acid solution, autoclaved at 115 °C for 30 min, and then 10 g of sulfur powder sterilized by atmospheric steaming for 2 h is added.

[0042] Preparation method of solid medium: Prepared by mixing three liquids A, B, and C. Solution A: Each 100 mL of distilled water contains 0.6 g of (NH4)2SO4, 0.6 g of KH2PO4, 0.1 g of MgSO4·7H2O, 0.05 g of CaCl2·2H2O, autoclaved at 115 °C for 30 min; Solution B: 2 g of agar powder is added to 100 mL of distilled water, autoclaved at 115 °C for 30 min; Solution C: Each 10 mL of distilled water contains 2 g of Na2S2O3, 0.006 g of FeSO4·7H2O, and filtered and sterilized. When Solution A and Solution B are cooled to 80 °C, they are mixed, then Solution C is added and mixed evenly, poured into a petri dish, and made into a solid medium after cooling.

[0043] The FCC waste catalyst is taken from Sinopec Qingdao Refining & Chemical Company.

[0044] The metal contents before and after biological leaching treatment are determined according to the determination method in "Determination of 22 Metal Elements in Solid Waste - Inductively Coupled Plasma Emission Spectrometry (HJ 781-2016)".

[0045] Example 1

[0046] This example is used to illustrate the screening of Thiobacillus thermophilus described in the present invention.

[0047] (1) Screening of Thiobacillus thermophilus, which is obtained by the following method:

[0048] The selected starting strain is Thiobacillus thermophilus ( Acidithiobacillus caldus ).

[0049] Take 5 mL of the starting strain bacterial solution and place it in an irradiation dish. Use ultraviolet lamps with intensities of 1000 lux, 1500 lux, and 2000 lux to irradiate the irradiation dish for 2 min - 10 min respectively. Among them, the concentration of the starting strain bacterial solution is 10 5 CFU / mL.

[0050] Prepare a biological leaching liquid medium, and add 80 mL of the biological leaching liquid medium and 20 g of FCC waste catalyst to a 250 mL Erlenmeyer flask to prepare a directional screening medium for high-concentration FCC waste catalyst. Add the above ultraviolet-mutated strain to the directional screening medium and continuously culture it for 7 - 10 days at 45 °C and 130 rpm.

[0051] Take the irradiated bacterial solution, dilute it 10 4 -10 6 times, and then take 100 μL of the diluted solution and spread it on a solid medium plate. Incubate it upside down at 37 °C for 2 - 3 days until colonies appear on the plate.

[0052] Pick the colonies into the biological leaching liquid medium, culture them for 3 - 5 days, and then through dilution, spreading on the solid medium, culturing, and picking colonies for culture, a strain with pure culture is obtained.

[0053] The mutagenized UVS10 was deposited at the China Center for Type Culture Collection (CCTCC) on June 9, 2021, with the deposit number CCTCC No: M 2021708.

[0054] Example 2

[0055] This example is used to illustrate the performance evaluation of the thermophilic Thiobacillus described in the present invention.

[0056] Prepare a biological leaching medium, and then inoculate the starting strain and UVS10 into the biological leaching medium respectively for shake flask culture and fermenter culture in sequence. The shake flask culture conditions are 45 °C and 130 rpm for 72 h. The fermenter culture conditions are 40 - 45 °C, the aeration rate is 0.1 vvm, and after continuous culture for 96 h, a biological leaching agent is obtained for treating FCC waste catalyst. The viable count of the biological leaching agent corresponding to each strain reaches 10 8 CFU / mL.

[0057] Add 20 g of FCC waste catalyst and 80 mL of bacterial solution to a 250 mL Erlenmeyer flask respectively, and culture at 45 °C and 130 rpm. After continuous culture for 7 days, take the leached FCC waste catalyst, wash and dry it, and then measure the metal content.

[0058] After measurement, the removal of metals in the FCC waste catalyst after treatment with different strains is shown in Table 1.

[0059] Table 1

[0060] <![CDATA[Metal content (mg·g -1 )]]> Ni V Sb La Ce Content in FCC spent catalyst 3.28 5.25 1.67 12.75 5.38 Content after treatment of starting strain 2.98(9.1％) 4.09(22.1％) 1.35(19.1％) 9.56(25.0％) 4.86(9.7％) Content after treatment with UVS10 1.38(58.0％) 1.97(62.5％) 0.35(79.1％) 3.58(71.9％) 1.99(63.0％)

[0061] Note: The metal removal rate is shown in brackets.

[0062] Compared with the starting strain, the strain UVS10 (deposit number: CCTCC No: M 2021708) described in the present invention has a significantly improved efficiency in the bioleaching treatment of metals in FCC waste catalysts.

[0063] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. An Acidithiobacillus caldus, characterized in that, The preservation number of the Acidithiobacillus caldus is CCTCC No: M 2021708.

2. A bacterial agent, characterized in that, The bacterial agent contains the Acidithiobacillus caldus as described in claim 1.

3. The microbial agent according to claim 2, wherein, The bacterial agent is a liquid bacterial agent.

4. Use of the Acidithiobacillus caldus as described in claim 1 and / or the bacterial agent as described in claim 2 or 3 in bioleaching.

5. Use of the Acidithiobacillus caldus as described in claim 1 and / or the bacterial agent as described in claim 2 or 3 in bioleaching for removing metals from waste.

6. A method for removing metals from waste by biological leaching, characterized in that, The method includes: contacting the Acidithiobacillus caldus as described in claim 1 and / or the bacterial agent as described in claim 2 or 3 with the waste.

7. The method according to claim 6, wherein The Acidithiobacillus caldus contacts the waste in the form of a bacterial agent, and the preparation method of the bacterial agent includes: inoculating the Acidithiobacillus caldus into a bioleaching medium for enrichment culture to obtain a seed liquid, and then inoculating the seed liquid into the bioleaching medium for fermentation to obtain the bacterial agent.

8. The method according to claim 7, wherein, The bioleaching medium contains: (NH4)2SO4 2 - 3 g / L, KH2PO4 2 - 4 g / L, MgSO4·7H2O 0.3 - 0.7 g / L, CaCl2 0.2 - 0.3 g / L, FeSO4 0.005 - 0.02 g / L, and sulfur powder 8 - 15 g / L; the pH of the bioleaching medium is 2.5 - 3.

5.

9. The method according to claim 7, wherein The conditions for the enrichment culture include: temperature of 40 - 45 °C and time of 48 - 96 h; The conditions for the fermentation include: temperature of 40 - 45 °C, time of 24 - 120 h; aeration rate of 0.05 - 0.2 vvm.

10. The method according to claim 7, wherein, The viable count of Thiobacillus thermophilus in the microbial agent is 10 8 cfu / mL or more.

11. The method according to claim 6 or 7, wherein, The waste is FCC spent catalyst.

12. The method according to claim 11, wherein, Compared with 1 L of the bacterial agent, the addition amount of the FCC spent catalyst is 150 - 200 g.

13. The method according to claim 12, wherein, The conditions for the contact include: temperature of 40 - 45 °C and time of 5 - 7 days.