Thiobacillus ferrooxidans flow culture device and method under low iron concentration condition

Abstract

The invention relates to the technical field of microorganism in-situ leaching uranium mining, and particularly discloses a device and a method for flow culture of thiobacillus ferrooxidans under the condition of low iron concentration. The device comprises a culture medium tank, an oxidation tank module and a liquid injection tank, the culture medium tank is arranged at the leftmost end of the device, and the top is provided with a lower injection pipeline and a concentrated sulfuric acid pipeline; a first oxidation tank, a second oxidation tank, a third oxidation tank, a fourth oxidation tank, a fifth oxidation tank, a sixth oxidation tank, a seventh oxidation tank and an eighth oxidation tank of the oxidation tank module are sequentially connected in series through oxidation tank pipelines; the first oxidation tank and the eighth oxidation tank are connected through a mature bacterial liquid return pipe; the first oxidation tank and the fourth oxidation tank are respectively matched with a glasses tube and a culture medium tank; and a liquid injection tank is arranged at the right end of the oxidation tank module and is connected with an eighth oxidation tank through a connecting pump. The device improves the living environment of the thiobacillus ferrooxidans, increases the activity of the thiobacillus ferrooxidans, shortens the adjustment period and logarithmic phase in the growth cycle of bacteria, and improves the production quantity of bacteria liquid.

Description

Technical Field

[0001] The present invention belongs to the technical field of microbial in-situ uranium leaching, and particularly relates to an apparatus and method for the flowing culture of Acidithiobacillus ferrooxidans under low iron concentration conditions. Background Art

[0002] Microbial ore leaching is a hydrometallurgical process in which certain microorganisms are used to catalyze the dissolution of metals in ores. It is particularly suitable for the heap leaching and in-situ leaching of lean ores, waste ores, off-specification ores, and refractory, difficult-to-separate, and difficult-to-smelt ores. It has the advantages of simple equipment, convenient operation, low cost, and less pollution, and is conducive to comprehensive utilization and environmental protection. Therefore, the research progress and application of microbial ore leaching technology have attracted more and more extensive attention. In the late 1970s, the Beijing Research Institute of Chemical Engineering and Metallurgy conducted research on the continuous oxidation of ferrous iron by bacteria and carried out an enlarged test of countercurrent leaching of four columns in series by bacteria at room temperature in the Benxi uranium mine. Subsequently, semi-industrial tests and heap leaching tests were successively carried out in the Fuzhou uranium mine in 1995 and 2000. Although good test results were obtained, due to the high operating cost, it has not been able to be put into industrial application.

[0003] At present, the leaching method in in-situ leaching mines in China is mainly acid leaching. With the advancement of large-scale industrialized mining, the volume of the head orebody decreases year by year, the proportion of lean ore and wing orebody is relatively large, the original uranium concentration in the solution is also decreasing continuously, and many other factors will inevitably lead to an annual increase in the production cost of in-situ leaching. Using bacterial leaching can effectively increase the oxidation-reduction potential, increase the original uranium concentration in the solution or alleviate its downward trend, thereby reducing the production cost. However, the permeability of the wing orebody is relatively poor. When a bacterial solution with a high iron concentration is applied to this orebody, Fe 3+ is likely to precipitate underground, block the ore-bearing aquifer, and affect in-situ leaching production; in addition, through analysis and research, Fe 3+ ions have a certain influence on the process of resin adsorption of uranium. When the concentration of Fe 3+ increases, the adsorption breakthrough volume decreases, the saturation volume increases, and the saturated uranium concentration of the resin decreases; secondly, the addition of ferrous sulfate undoubtedly increases the production cost and affects the economic benefits of the enterprise, which greatly restricts the industrial application of microbial in-situ uranium leaching. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an apparatus and method for the flowing culture of Acidithiobacillus ferrooxidans under low iron concentration conditions to solve the problem of culturing Acidithiobacillus ferrooxidans that can be used for uranium extraction by microorganisms in view of the above deficiencies in the prior art.

[0005] To solve the above problems, the technical solution of the present invention is as follows: A Thiobacillus ferrooxidans flow culture device under low iron concentration conditions, the device includes a culture medium tank, an oxidation tank module, and a liquid injection tank; the culture medium tank is placed at the leftmost end of the device, and a lower liquid injection pipe and a concentrated sulfuric acid pipe are provided at the top. The lower liquid injection pipe is used to input tail liquid into the culture medium tank, and the concentrated sulfuric acid pipe is used to input concentrated sulfuric acid into the culture medium tank; the oxidation tank module includes a first oxidation tank, a second oxidation tank, a third oxidation tank, a fourth oxidation tank, a fifth oxidation tank, a sixth oxidation tank, a seventh oxidation tank, and an eighth oxidation tank; the first oxidation tank, the second oxidation tank, the third oxidation tank, the fourth oxidation tank, the fifth oxidation tank, the sixth oxidation tank, the seventh oxidation tank, and the eighth oxidation tank are sequentially connected in series through oxidation tank pipes; a mature bacterial liquid reflux pipe is connected between the first oxidation tank and the eighth oxidation tank to realize the addition of mature bacterial liquid to the first oxidation tank at the head end; the first oxidation tank and the fourth oxidation tank are respectively connected to the culture medium tank through distribution pipes to obtain culture medium liquid; the right end of the oxidation tank module is a liquid injection tank, and the liquid injection tank is connected to the eighth oxidation tank through a connection pump to obtain mature bacterial liquid.

[0006] The top of the liquid injection tank is provided with a main liquid pipe for outputting the bacterial liquid in the liquid injection tank.

[0007] The top of the liquid injection tank is provided with a mature bacterial liquid pipe for the third oxidation tank, which is used to transfer the bacterial liquid in the liquid injection tank to the mature bacterial liquid pipe for the third oxidation tank.

[0008] The top of the liquid injection tank is connected with a concentrated sulfuric acid pipe for transmitting concentrated sulfuric acid into the liquid injection tank to adjust the pH value of the liquid injection tank.

[0009] The top of the liquid injection tank is connected with a lower liquid injection pipe for transmitting tail liquid into the liquid injection tank.

[0010] The volume of the oxidation tank is 45m 3 , and a net-like membrane is hung in the tank.

[0011] A method for culturing Thiobacillus ferrooxidans under low iron concentration conditions, the method includes the following operating steps:

[0012] Step 1: Adjust the pH of the solution in the culture medium tank to form a culture medium

[0013] Inject the tail liquid into the culture medium tank through the lower liquid injection pipe, and add concentrated sulfuric acid to the culture medium tank through the concentrated sulfuric acid pipe to form a culture medium;

[0014] Step 2: Culture the bacterial liquid in the oxidation tank module

[0015] Transport the culture medium to the series-connected oxidation tanks through a pump, control the flow rate at 15m 3 / h, control the aeration volume, so that Thiobacillus ferrooxidans grows and reproduces between the oxidation tank groups, and a mature bacterial liquid with higher activity is formed in the eighth oxidation tank;

[0016] Step 3: pH adjustment of the liquid injection tank

[0017] The mature bacterial liquid flowing out of the eighth oxidation tank is transported to the liquid injection tank by a pump. After adding concentrated sulfuric acid to the liquid injection tank through the concentrated sulfuric acid pipeline to adjust the pH, it is output through the liquid injection pipe;

[0018] Step 4: Supplementary addition of mature bacterial liquid in the first oxidation tank

[0019] The mature bacterial liquid produced in the eighth oxidation tank is transported to the first oxidation tank by a pump for supplementary addition of mature bacterial liquid, increasing the density of Acidithiobacillus ferrooxidans in the culture medium, improving the bacterial activity, forming a reflux continuous culture, and increasing the production of bacterial liquid.

[0020] In Step 1, the pH value range of the culture medium is.

[0021] The remarkable effect of the present invention is that a flowing culture device and method for Acidithiobacillus ferrooxidans under low iron concentration conditions of the present invention include the following beneficial effects:

[0022] (1) By domesticating the bacterial strain, Acidithiobacillus ferrooxidans can reproduce and survive under the condition of a relatively low liquid temperature (14 °C), and a microbial strain under low temperature conditions is obtained.

[0023] (2) Using the adsorbed tail liquid as the culture medium, Acidithiobacillus ferrooxidans is cultured without adding an external iron source. Acidithiobacillus ferrooxidans can completely survive, divide and reproduce, and 30 m of bacterial liquid can be produced per hour in a 45 m oxidation tank within a unit time, and the contact oxidation time is increased by 1.4 times compared with the iron concentration of 3.0 g / l, and the production efficiency of the bacterial liquid is significantly improved. 3 The oxidation tank can produce 30 m of bacterial liquid 3 / h, and the contact oxidation time is increased by 1.4 times compared with the iron concentration of 3.0 g / l, and the production efficiency of the bacterial liquid is significantly improved.

[0024] (3) The flowing culture mode of Acidithiobacillus ferrooxidans, compared with the fixed culture with a constant volume, due to the continuous addition of the culture medium, improves the living environment of Acidithiobacillus ferrooxidans, increases its activity, shortens the adjustment period and logarithmic period in the bacterial growth cycle, and increases the production of bacterial liquid. Description of the drawings

[0025] Figure 1 It is a schematic structural diagram of a flowing culture device for Acidithiobacillus ferrooxidans under low iron concentration conditions of the present invention;

[0026] In the figure: 1. Culture medium tank; 2. First oxidation tank; 3. Second oxidation tank; 4. Third oxidation tank; 5. Fourth oxidation tank; 6. Fifth oxidation tank; 7. Sixth oxidation tank; 8. Seventh oxidation tank; 9. Eighth oxidation tank; 10. Liquid injection tank; 11. Lower liquid injection pipeline; 12. Concentrated sulfuric acid pipeline; 13. Liquid injection pipe; 14. Mature bacterial liquid reflux pipe; 15. Mature bacterial liquid pipe of the third oxidation tank. Detailed implementation mode

[0027] The following will clearly and completely describe the technical solutions in the present invention in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative work belong to the scope of the present invention.

[0028] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper" is based on the orientation or positional relationship shown in the accompanying drawings. It is only for convenience and simplified description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention.

[0029] In the description of the present invention, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, terms such as "connection", "setting", "installation", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] As Figure 1 shown, a Thiobacillus ferrooxidans flow culture device under low iron concentration conditions, the device includes a culture medium tank 1, an oxidation tank module, and a liquid injection tank 10; the culture medium tank 1 is placed at the leftmost end of the device, and a lower liquid injection pipeline 11 and a concentrated sulfuric acid pipeline 12 are provided at the top. The lower liquid injection pipeline 11 is used to input tail liquid into the culture medium tank 1, and the concentrated sulfuric acid pipeline 12 is used to input concentrated sulfuric acid into the culture medium tank 1;

[0032] The oxidation tank module includes a first oxidation tank 2, a second oxidation tank 3, a third oxidation tank 4, a fourth oxidation tank 5, a fifth oxidation tank 6, a sixth oxidation tank 7, a seventh oxidation tank 8, and an eighth oxidation tank 9; the first oxidation tank 2, the second oxidation tank 3, the third oxidation tank 4, the fourth oxidation tank 5, the fifth oxidation tank 6, the sixth oxidation tank 7, the seventh oxidation tank 8, and the eighth oxidation tank 9 are sequentially connected in series through oxidation tank pipelines; the first oxidation tank 2 and the eighth oxidation tank 9 are connected through a mature bacterial liquid reflux pipe 14 to realize the supplementation of mature bacterial liquid in the first oxidation tank at the head end; the first oxidation tank 2 and the fourth oxidation tank 5 are respectively connected to the culture medium tank 1 through a distribution pipe to obtain culture medium liquid;

[0033] The right end of the oxidation tank module is a liquid injection tank 10, and the liquid injection tank 10 is connected to the eighth oxidation tank 9 through a connection pump to obtain mature bacterial liquid;

[0034] As an embodiment, a main liquid pipe 13 is provided at the top of the liquid injection tank 10 for outputting the bacterial liquid in the liquid injection tank 10;

[0035] As an embodiment, a mature bacterial liquid pipe 15 of the third oxidation tank is provided at the top of the liquid injection tank 10 for transmitting the bacterial liquid in the liquid injection tank 10 to the mature bacterial liquid pipe 15 of the third oxidation tank;

[0036] As an embodiment, a concentrated sulfuric acid pipe 12 is connected to the top of the liquid injection tank 10 for transmitting concentrated sulfuric acid into the liquid injection tank 10 to adjust the pH value of the liquid injection tank 10;

[0037] As an embodiment, a lower liquid injection pipeline 11 is connected to the top of the liquid injection tank 10 for transmitting tail liquid into the liquid injection tank 10;

[0038] As an embodiment, the volume of the oxidation tank is 45m 3 , and a net-like membrane is hung in the tank;

[0039] A method for flowing culture of Thiobacillus ferrooxidans under low iron concentration conditions, the method comprising the following operating steps:

[0040] Step 1, pH adjustment of the solution in the culture medium tank 1 to form a culture medium

[0041] Inject the tail liquid into the culture medium tank 1 through the lower liquid injection pipeline 11, and add concentrated sulfuric acid to the culture medium tank 1 through the concentrated sulfuric acid pipeline 12 to form a culture medium.

[0042] Step 2, culturing the bacterial liquid in the oxidation tank module

[0043] Transport the culture medium to the series-connected oxidation tanks through a pump, control the flow rate at 15m 3 / h, control the aeration volume, so that Thiobacillus ferrooxidans grows and reproduces among the oxidation tank groups, and a mature bacterial liquid with higher activity is formed in the eighth oxidation tank 9.

[0044] Step 3, pH adjustment of the liquid injection tank 10

[0045] The mature bacterial liquid flowing out of the eighth oxidation tank 9 is transported to the liquid injection tank 10 through a pump, concentrated sulfuric acid is added to the liquid injection tank 10 through the concentrated sulfuric acid pipeline 12 to adjust the pH, and then it is output through the liquid injection pipe 13.

[0046] Step 4, supplementing the mature bacterial liquid in the first oxidation tank 2

[0047] The mature bacterial liquid produced in the eighth oxidation tank 9 is pumped to the first oxidation tank 2 for supplementing the mature bacterial liquid, increasing the density of Acidithiobacillus ferrooxidans in the culture medium, enhancing the bacterial activity, forming a reflux continuous culture, and increasing the production of the bacterial liquid.

[0048] In step 1, the pH value range of the culture medium is (1.6, 1.8).

[0049] (1) Acidithiobacillus ferrooxidans belongs to aerobic acidophilic bacteria. The oxygen content in the air can meet the growth requirements of the microorganisms. In the flowing culture medium, a moderate aeration volume should be controlled, and the pH should be controlled at 1.60 - 1.80.

[0050] (2) In the flowing culture medium, when oxygen is introduced, CO2 is added to supplement the carbon source required for the bacterial production activities by using CO2.

[0051] (3) The energy source for the growth of Acidithiobacillus ferrooxidans is Fe 2+ , and the tail liquid contains a certain concentration of Fe 2+ . To prepare the culture medium and rationally utilize the principle of bacterial metabolism, to reduce the death of bacteria due to lack of energy during the flowing culture process, control the flow rate of the culture medium so that Fe 2+ is just completely oxidized in the last oxidation tank of the flowing culture to ensure the density and activity of the bacteria.

[0052] (4) The volume of a single oxidation tank is 45 m 3 . A net-like membrane is hung in the tank to provide conditions for the attachment of Acidithiobacillus ferrooxidans. The flowing culture of the bacterial liquid is carried out in two groups. Oxidation tanks 1 - 4 are connected in series as one group, and oxidation tanks 5 - 8 are connected in series as one group.

[0053] (5) The mature bacterial liquid formed by connecting oxidation tanks 1 - 4 in series is pumped to the injection tank, and the mature bacterial liquid formed by connecting oxidation tanks 5 - 8 in series flows into the injection tank through a gravity flow pipe. The flow rate of the series group is controlled at 15 m 3 / h.

[0054] (6) The mature bacterial liquid with stronger activity in the 5 - 8 series group is pumped to oxidation tanks 1 and 5 to complete the supplementation of the mature bacterial liquid, increasing the density of Acidithiobacillus ferrooxidans in the culture medium.

[0055] (1) Acidithiobacillus ferrooxidans belongs to aerobic acidophilic bacteria, and its growth conditions are required as follows:

[0056] ① Sufficient oxygen. The oxygen content in the air can meet the growth requirements of the microorganisms. In the flowing culture, to increase the bacterial film attachment effect and improve the oxidation rate, a moderate aeration volume should be controlled.

[0057] ② Energy - The source is Fe 2+ , rationally utilize the principle of bacterial metabolism, and oxidize all the Fe 2+ in the leaching solution into Fe3+ , resource leaching is carried out. To reduce the death of bacteria due to lack of energy during the flowing culture process, by controlling the flow rate of the culture medium, Fe 2+ is just completely oxidized in the last oxidation tank of the flowing culture to ensure the density and activity of the bacteria.

[0058] ③ pH. Since this bacterium is an acidophilic bacterium, the pH of the culture medium should be controlled at 1.60 - 1.80;

[0059] ④ Carbon source. CO2 is soluble in water. While providing oxygen, CO2 is used to supplement the carbon source required for the bacterial production activities.

[0060] ⑵ The requirements for the selection of the culture medium are as follows:

[0061] The adsorption tail liquid (pH value is about 1.70, ∑Fe concentration is about 1.4 g / L, Fe 2+ concentration is about 1.0 g / L) after the acid leaching solution is treated by resin adsorption is directly input into the culture medium tank for culturing Thiobacillus ferrooxidans. Without adding external iron source and acid, Fe in the tail liquid is directly used 2+ as a nutrient to maintain the growth of bacteria. The flowing culture method is adopted. During the growth of bacteria, the flow rate of the culture medium (including the reflux of mature bacterial liquid, the shunt of the culture medium, and the culture process of the bacterial liquid, etc.) is continuously adjusted to improve the production efficiency of the bacteria.

[0062] Enlightened by the ideal embodiments of the present invention as described above, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A Thiobacillus ferrooxidans flow culture device under low iron concentration conditions, characterized in that: The device includes a culture medium tank (1), an oxidation tank module, and a liquid injection tank (10); the culture medium tank (1) is placed at the leftmost end of the device, and a lower liquid injection pipe (11) and a concentrated sulfuric acid pipe (12) are provided at the top. The lower liquid injection pipe (11) is used to input tail liquid into the culture medium tank (1), and the concentrated sulfuric acid pipe (12) is used to input concentrated sulfuric acid into the culture medium tank (1); the oxidation tank module includes a first oxidation tank (2), a second oxidation tank (3), a third oxidation tank (4), a fourth oxidation tank (5), a fifth oxidation tank (6), a sixth oxidation tank (7), a seventh oxidation tank (8), and an eighth oxidation tank (9); the first oxidation tank (2), the second oxidation tank (3), the third oxidation tank (4), the fourth oxidation tank (5), the fifth oxidation tank (6), the sixth oxidation tank (7), the seventh oxidation tank (8), and the eighth oxidation tank (9) are sequentially connected in series through oxidation tank pipes; the first oxidation tank (2) and the eighth oxidation tank (9) are connected through a mature bacterial liquid reflux pipe (14) to achieve the supplementation of mature bacterial liquid in the first oxidation tank at the head end; the first oxidation tank (2) and the fourth oxidation tank (5) are respectively connected to the culture medium tank (1) through distribution pipes to obtain culture medium liquid; the right end of the oxidation tank module is a liquid injection tank (10), and the liquid injection tank (10) is connected to the eighth oxidation tank (9) through a connection pump to obtain mature bacterial liquid.

2. The flow cultivation device for Acidithiobacillus ferrooxidans under the condition of low iron concentration according to claim 1, wherein: A main liquid pipe (13) is provided at the top of the liquid injection tank (10) for outputting the bacterial liquid in the liquid injection tank (10).

3. A Thiobacillus ferrooxidans flow culture device under low iron concentration conditions according to claim 1, characterized in that: A mature bacterial liquid pipe (15) of the third oxidation tank is provided at the top of the liquid injection tank (10) for transporting the bacterial liquid in the liquid injection tank (10) to the mature bacterial liquid pipe (15) of the third oxidation tank.

4. The flow cultivation device for Acidithiobacillus ferrooxidans under the condition of low iron concentration according to claim 1, wherein: A concentrated sulfuric acid pipe (12) is connected to the top of the liquid injection tank (10) for transporting concentrated sulfuric acid into the liquid injection tank (10) to adjust the pH value of the liquid injection tank (10).

5. A Thiobacillus ferrooxidans flow culture device under low iron concentration conditions according to claim 1, characterized in that: A lower liquid injection pipe (11) is connected to the top of the liquid injection tank (10) for transporting tail liquid into the liquid injection tank (10).

6. A Thiobacillus ferrooxidans flow culture device under low iron concentration conditions according to claim 1, characterized in that: The volume of the oxidation tank is 45 m 3 , and a net-shaped membrane is hung in the tank.

7. A method for the flow cultivation of Acidithiobacillus ferrooxidans under low iron concentration conditions, characterized in that: The method includes the following operating steps: Step 1: Adjust the pH of the solution in the culture medium tank (1) to form a culture medium Inject the tail liquid into the culture medium tank (1) through the lower liquid injection pipe (11), and add concentrated sulfuric acid to the culture medium tank (1) through the concentrated sulfuric acid pipe (12) to form a culture medium; Step 2: Cultivate the bacterial liquid in the oxidation tank module The culture medium is pumped into the series-connected oxidation tanks, and the flow rate is controlled at 15 m 3 / h. The aeration volume is controlled to enable the growth and reproduction of Thiobacillus ferrooxidans between the oxidation tank groups, and a mature bacterial solution with relatively high activity is formed in the eighth oxidation tank (9). Step 3: Adjust the pH of the liquid injection tank (10) The mature bacterial liquid flowing out of the eighth oxidation tank (9) is transported to the liquid injection tank (10) by a pump. After adding concentrated sulfuric acid to the liquid injection tank (10) through the concentrated sulfuric acid pipe (12) to adjust the pH, it is output through the liquid injection pipe (13); Step 4: Supplement the mature bacterial liquid in the first oxidation tank (2) The mature bacterial liquid generated by the eighth oxidation tank (9) is transported to the first oxidation tank (2) by a pump for supplementing the mature bacterial liquid, increasing the density of ferrous sulfate-oxidizing bacteria in the culture medium, improving the bacterial activity, forming a reflux continuous culture, and increasing the production of bacterial liquid.

8. A method for the flow cultivation of Thiobacillus ferrooxidans under low ferrous iron concentration conditions according to claim 7, characterized in that: In Step 1, the pH value range of the culture medium is (1.6, 1.8).

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