A bioheap leaching process for hard rock type uranium ores
By constructing an integrated bio-heap leaching device and precisely controlling key parameters, the problems of low leaching efficiency and high cost of hard rock low-grade uranium ore have been solved, achieving efficient, economical and environmentally friendly uranium ore recovery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANCHANG CAMPUS OF EAST CHINA UNIV OF TECH
- Filing Date
- 2026-02-12
- Publication Date
- 2026-06-12
AI Technical Summary
Existing technologies for processing low-grade uranium ore in hard rock have problems such as low leaching efficiency, high cost, and significant environmental impact. In particular, traditional acid heap leaching processes have high acid consumption, low leaching rates, and are environmentally unfriendly. Bio-heap leaching technology has failed to achieve effective coupling and refined control in the industrial application of complex hard rock uranium ore.
A step-by-step, sequential integrated bio-heap leaching method is adopted. By constructing a device that includes a leaching column, an acidizing solution storage tank, and a bio-bacterial solution storage tank, key parameters of the acidizing pretreatment and bioleaching stages, such as the flow rate, acidity, liquid-to-solid ratio, and concentration of the acidizing solution and leaching solution, are precisely controlled to achieve closed-loop circulation leaching of uranium ore.
It significantly improves uranium leaching efficiency and economics, increasing the leaching rate from approximately 65% to 92.9%, reducing production costs by 30%-50%, shortening the leaching cycle by nearly 10 times, and reducing pollutant generation, thus meeting the requirements of green mining.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of bioleaching technology, and more particularly to a bioleaching method for hard rock uranium deposits. Background Technology
[0002] Uranium resources are a core mineral related to energy self-sufficiency and strategic security. With the increasing scarcity of high-grade, easily processed uranium ore resources, low-grade, difficult-to-leach uranium ore has become the main focus of future mining. Therefore, the development of efficient and low-cost green leaching technologies is of urgent practical significance.
[0003] Currently, the industrial treatment of such ores mainly relies on the traditional acid heap leaching process. However, this method faces significant challenges in practical applications: its processing cost is high due to the huge consumption of acid (up to 2.5%-4.0% of the ore weight); at the same time, the leaching efficiency is low, with a cycle of several months and a leaching rate of only about 65%; in addition, it is accompanied by severe environmental pressure, as the large amount of high-salinity wastewater generated by high acid consumption increases the difficulty of subsequent treatment and environmental risks.
[0004] Bioleaching technology utilizes the catalytic oxidation of microorganisms, providing a new approach to green metallurgy. Compared with traditional acid leaching, this technology theoretically has potential advantages such as low acid consumption, no need for external chemical oxidants, and environmental friendliness. However, its industrial application in complex hard-rock uranium ores still faces key bottlenecks. On the one hand, existing processes lack sufficient ore pretreatment; acid-consuming minerals in the ore cause drastic fluctuations in the pH of the leaching system, severely inhibiting the activity of leaching microorganisms. On the other hand, existing technical parameter systems are coarse, failing to systematically decouple and finely coordinate the acid pretreatment and bioleaching stages, resulting in leaching rates and final recovery rates that are difficult to meet the requirements of efficient industrial production.
[0005] Therefore, a complete solution is needed that can effectively couple chemical pretreatment and bioleaching, and achieve precise and coordinated control of key parameters throughout the process. Summary of the Invention
[0006] This invention aims to overcome the above-mentioned defects and proposes an innovative, step-by-step, sequential, and parameter-optimized integrated bio-heap leaching method, which realizes efficient, economical, and green recovery of hard rock-type low-grade uranium ore.
[0007] This invention provides a bioleaching method for hard-rock uranium ore, the specific steps of which include: S1. Construct a bio-heap leaching device comprising a leaching column, an acidification solution storage tank, a biological bacterial solution storage tank, an acidification solution circulation pump, and a leaching solution circulation pump; wherein, the leaching column adopts a bottom-in, top-out operation mode: the leaching column has an inlet at the bottom and an outlet at the top, and a permeation layer is laid at the bottom of the column, with uranium ore filled on the permeation layer; when the device is running, the liquid in the storage tank is pumped into the leaching column from the bottom by the circulation pump, and finally flows back to the corresponding storage tank from the top outlet; S2. Prepare acidifying solution in acidifying solution storage tank, and pump the acidifying solution into leaching column containing uranium ore through circulation pump. Set the rising flow rate of acidifying solution in leaching column and acidification reaction time to perform closed-loop circulation leaching of uranium ore; wherein, the acidifying solution comes from the adsorption tailings of CNNC Shaoguan Jinyuan Uranium Industry Hydrometallurgical Plant. S3. In the biological bacterial solution storage tank, the leaching bacterial solution is prepared based on the adsorption tailings of Jinyuan Uranium Industry Hydrometallurgical Plant. The leaching bacterial solution is pumped into the leaching column that has completed acidification pretreatment by a circulation pump. The upward flow rate of the leaching bacterial solution and the leaching time are set to perform closed-loop circulation leaching of the acidified uranium ore. The key process parameters of the leaching bacterial solution include the iron concentration of the bacterial solution, the acidity of the bacterial solution, and the liquid-solid ratio of the bacterial solution to the uranium ore.
[0008] Furthermore, the acidity of the acidification solution in step S2 is 4-39 g / L.
[0009] Preferably, the acidity of the acidification solution in step S2 is 10 g / L.
[0010] Furthermore, the upward flow rate of the acidified liquid in step S2 is 0.13-0.76 m / h.
[0011] Preferably, the upward flow rate of the acidified liquid in step S2 is 0.38 m / h.
[0012] Furthermore, the acidification reaction time in step S2 is 2-4 h.
[0013] Furthermore, the biological bacterial solution mentioned in step S3 is obtained by using the adsorption tailings from the hydrometallurgical plant of CNNC Shaoguan Jinyuan Uranium Industry as a culture medium and through long-term domestication of functional bacterial groups. The main dominant bacteria in the biological bacterial solution are acidophilic ferrooxidizing thiobacillus, iron-oxidizing Leptospira, and acidophilic thiooxidizing thiobacillus.
[0014] Furthermore, in step S3, the liquid-to-solid ratio of the leaching solution to the uranium ore is 1-6:1 L / kg.
[0015] Preferably, the liquid-to-solid ratio of the leaching solution to the uranium ore in step S3 is 2:1 L / kg.
[0016] Furthermore, the acidity of the leaching solution in step S3 is 4-9 g / L.
[0017] Preferably, the acidity of the leaching solution in step S3 is 4 g / L.
[0018] Furthermore, the concentration of ferric iron in the leaching solution in step S3 is 0.6-5.6 g / L.
[0019] Preferably, the concentration of ferric iron in the leaching solution in step S3 is 1.0 g / L.
[0020] Furthermore, the upward flow rate of the leaching solution in step S3 is 0.13-0.76 m / h.
[0021] Preferably, the upward flow rate of the leaching solution in step S3 is 0.38 m / hm / h.
[0022] Furthermore, the leaching reaction time in step S3 is 48-316 h.
[0023] This invention provides a bioleaching method for hard-rock uranium deposits. By precisely controlling a series of key parameters in the two stages of "acidification pretreatment" and "bioleaching," it achieves significant improvements in technical, economic, and environmental benefits. Compared with existing technologies, this invention has the following advantages: 1) Significant breakthroughs have been achieved in leaching efficiency and cycle. Under optimized parameters, the bacterial leaching system achieves a uranium leaching rate of 92.9% within 316 hours, significantly reducing the efficient leaching cycle from the traditional approximately 100 days to approximately 13 days, improving efficiency by nearly 10 times.
[0024] 2) Production costs and resource consumption are effectively reduced. By optimizing process parameters, the overall acid consumption is reduced by 30%-50% compared with the traditional acid method. An economical bacterial liquid iron concentration (1.6 g / L) and liquid-solid ratio (2:1) have been established. At the same time, the dependence on high-priced chemical oxidants is reduced by utilizing the regenerative oxidation capacity of microorganisms themselves.
[0025] 3) The synergy and environmental friendliness of the process have been significantly enhanced. Through systematic experiments, an intrinsic synergistic process system containing six core optimal parameters was constructed, thereby reducing the generation of pollutants from the source and fully meeting the requirements of green mining. Attached Figure Description
[0026] Figure 1 A flowchart illustrating the steps of a bio-heap leaching method for hard rock uranium ore provided in this embodiment of the invention.
[0027] Figure 2 This shows the uranium concentration under different acidity conditions during the acidification stage.
[0028] Figure 3 This shows the changes in acidity under different acidity conditions during the acidification stage.
[0029] Figure 4 The variation of uranium concentration under different upflow velocities during the acidification stage.
[0030] Figure 5 This shows the acidity changes under different upward flow rates during the acidification stage.
[0031] Figure 6 This shows the changes in uranium concentration under different liquid-to-solid ratios during the bactericidal immersion stage.
[0032] Figure 7 The acidity changes under different liquid-to-solid ratios during the bacterial immersion stage.
[0033] Figure 8 Fe under different liquid-solid ratios during the bacterial immersion stage 3+ Total consumption.
[0034] Figure 9 This shows the changes in uranium concentration under different acidity conditions during the bacterial immersion stage.
[0035] Figure 10 This shows the changes in acidity under different acidity conditions during the bacterial immersion stage.
[0036] Figure 11 Fe under different acidity conditions during the bacterial immersion stage 3+ Concentration changes.
[0037] Figure 12 This shows the changes in uranium concentration under different ferric iron concentrations during the bactericidal leaching stage.
[0038] Figure 13 The acidity changes under different ferric concentrations during the bacterial immersion stage.
[0039] Figure 14 Fe under different ferric iron concentrations during the bacterial immersion stage 3+ Concentration changes.
[0040] Figure 15 This shows the changes in uranium concentration under different upward flow rates during the bactericidal immersion stage.
[0041] Figure 16 Fe under different upward flow rates during the bacterial immersion stage 3+ Concentration changes.
[0042] Figure 17 This is a graph showing the variation of uranium concentration in each leaching stage of the bacterial solution leaching system and the tail liquid leaching system. Detailed Implementation
[0043] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification.
[0044] Please see Figure 1 , Figure 1 A flowchart illustrating the steps of a bioleaching method for hard-rock uranium ore provided in this embodiment of the invention includes: S1. Construct a bio-heap leaching device comprising a leaching column, an acidification solution storage tank, a biological bacterial solution storage tank, an acidification solution circulation pump, and a leaching solution circulation pump; wherein, the leaching column adopts a bottom-in, top-out operation mode: the leaching column has an inlet at the bottom and an outlet at the top, and a permeation layer is laid at the bottom of the column, with uranium ore filled on the permeation layer; when the device is running, the liquid in the storage tank is pumped into the leaching column from the bottom by the circulation pump, and finally flows back to the corresponding storage tank from the top outlet; S2. Prepare acidifying solution in acidifying solution storage tank, and pump the acidifying solution into leaching column containing uranium ore through circulation pump. Set the rising flow rate of acidifying solution in leaching column and acidification reaction time to perform closed-loop circulation leaching of uranium ore; wherein, the acidifying solution comes from the adsorption tailings of CNNC Shaoguan Jinyuan Uranium Industry Hydrometallurgical Plant. S3. In the biological bacterial solution storage tank, the leaching bacterial solution is prepared based on the adsorption tailings of Jinyuan Uranium Industry Hydrometallurgical Plant. The leaching bacterial solution is pumped into the leaching column that has completed acidification pretreatment by a circulation pump. The upward flow rate of the leaching bacterial solution and the leaching time are set to perform closed-loop circulation leaching of the acidified uranium ore. The key process parameters of the leaching bacterial solution include the iron concentration of the bacterial solution, the acidity of the bacterial solution, and the liquid-solid ratio of the bacterial solution to the uranium ore.
[0045] This invention uses the adsorption tailings from the hydrometallurgical plant of CNNC Shaoguan Jinyuan Uranium Industry as the culture medium and a mixed bacterial flora from the laboratory as the bacterial source. Through long-term domestication of the functional bacterial flora, an experimental bacterial solution was obtained. The mixed bacteria in the bacterial solution are dominated by *Acidithibacillus ferrooxidans*, *Leptospirillum ferrooxidans*, and *Acidithibacillus thiooxidans*. Furthermore, the acidification leachate and the bioleaching bacterial solution were prepared using the adsorption tailings from the hydrometallurgical plant of CNNC Shaoguan Jinyuan Uranium Industry.
[0046] To clearly illustrate the technical solution, specific parameters, and technical effects of this invention, detailed descriptions are provided below with reference to specific embodiments. The optimal reaction parameters for the technical solution were determined through a small-scale column leaching test with 1 kg of ore, as detailed in Examples 1 to 36. Specific parameter settings for each example are shown in Table 1. Optimized conditions (acidification upflow rate, acidity of the acidification leaching solution, volume of the biological bacteria solution to the ore liquid-to-solid ratio, and Fe leaching by bacteria) were optimized. 3+ Further large-scale tests were conducted with 120 kg of ore under different concentrations, leaching solution acidity, and leaching solution upward flow rate. The bacterial solution leaching system was compared with the tailings leaching system to further analyze and verify the scheme. See Examples 37 and 38 for details.
[0047] Table 1 Control conditions for small-scale column leaching tests of ore Example 1 Acid leaching experiment of 1 kg uranium ore Step 1: Construct the experimental setup The experimental setup consists of an acrylic column (h=40cm, Φ=7cm, φ=6cm), a Lange BT100-3J peristaltic pump, silicone pump tubing, PVC tubing, and a polyethylene tank. The acrylic column has an inlet at the bottom and an outlet at the top. A permeate layer (approximately 2cm thick) is laid at the bottom of the column, filled with 1kg of uranium ore. The leaching solution operates in a bottom-in, top-out manner. The prepared acidified leaching solution is placed in the polyethylene tank (storage tank). The PVC tubing connecting the peristaltic pump is positioned below the water surface in the polyethylene tank (ensuring continuous inflow). After being pumped by the peristaltic pump, the solution enters through the inlet at the bottom of the acrylic column and finally flows back into the polyethylene tank through the outlet at the top.
[0048] Step 2: Uranium ore leaching Acid leaching solution was prepared in a polyethylene tank. First, a certain amount of adsorption tailings from the adsorption tower was added to the tank, and the acidity of the adsorption tailings was adjusted to 10 g / L. The acid leaching solution in the polyethylene tank was pumped from the bottom into an plexiglass column using a peristaltic pump. The speed of the peristaltic pump was adjusted to control the upward flow rate of the acid leaching solution in the plexiglass column at 0.38 m / h. 1 kg of uranium ore was subjected to acid leaching, and the leaching operation time was 2 hours. During the acid leaching operation, the acidity and uranium concentration in the polyethylene tank were measured periodically at initial, 15 min, 30 min, 45 min, 60 min, 90 min, and 120 min intervals.
[0049] Example 2 The difference from Example 1 is that in step 2, "adjusting the acidity of the adsorption tail liquid to 10 g / L with sulfuric acid" is changed to "adjusting the acidity of the adsorption tail liquid to 4 g / L with sulfuric acid". The other steps and conditions are the same as in Example 1.
[0050] Example 3 The difference from Example 1 is that in step 2, "adjusting the acidity of the adsorption tail liquid to 10 g / L with sulfuric acid" is changed to "adjusting the acidity of the adsorption tail liquid to 18 g / L with sulfuric acid". The other steps and conditions are the same as in Example 1.
[0051] Example 4 The difference from Example 1 is that in step 2, "adjusting the acidity of the adsorption tail liquid to 10 g / L with sulfuric acid" is changed to "adjusting the acidity of the adsorption tail liquid to 26 g / L with sulfuric acid". The other steps and conditions are the same as in Example 1.
[0052] Example 5 The difference from Example 1 is that in step 2, "adjusting the acidity of the adsorption tail liquid to 10 g / L with sulfuric acid" is changed to "adjusting the acidity of the adsorption tail liquid to 32 g / L with sulfuric acid". The other steps and conditions are the same as in Example 1.
[0053] Example 6 The difference from Example 1 is that in step 2, "adjusting the acidity of the adsorption tail liquid to 10 g / L with sulfuric acid" is changed to "adjusting the acidity of the adsorption tail liquid to 39 g / L with sulfuric acid". The other steps and conditions are the same as in Example 1.
[0054] Comparing Examples 1 to 6, the effect of different acidities on the acid leaching of uranium ore was analyzed to determine the optimal acidity. The changes in uranium concentration in the storage tank under different acidity conditions are shown below. Figure 2 As shown, the acidity changes are as follows: Figure 3 As shown.
[0055] Figure 2 and Figure 3 Experimental results show significant stage-specific characteristics in both uranium leaching and acid consumption processes. In uranium leaching, the initial acidity of 10 g / L exhibits optimal performance, with a significant secondary increase occurring in the later stages of the reaction (60-120 minutes), reaching a final uranium concentration of 0.60 g / L, the highest value throughout the entire experimental period. When the acidity increases to 26 g / L or higher, the final concentration increase plateaus (approximately 0.55 g / L), indicating an acidity threshold effect, suggesting that blindly increasing the acidity has no significant effect on improving the leaching rate. Regarding acid consumption, the decay patterns of different initial acidities further confirm the aforementioned acidity threshold effect. For example, the high acidity group (e.g., 39 g / L) still had a large amount of residual acid (32 g / L) after the reaction, indicating serious ineffective consumption and waste; while the acid consumption in the medium- and low acidity groups was more thorough.
[0056] A lower suitable acidity helps reduce the treatment load and environmental risks of subsequent waste liquid from the source. Taking into account leaching efficiency and economic cost, an acidity of 10 g / L is the optimal acidification acidity.
[0057] Example 7 The difference from Example 1 is that in step 2, "adjusting the speed of the peristaltic pump to control the upward flow rate of the acid leachate in the plexiglass column at 0.38 m / h" is changed to "adjusting the speed of the peristaltic pump to control the upward flow rate of the acid leachate in the plexiglass column at 0.13 m / h". The other steps and conditions are the same as in Example 1.
[0058] Example 8 The difference from Example 1 is that in step 2, "adjusting the speed of the peristaltic pump to control the upward flow rate of the acid leachate in the plexiglass column at 0.38 m / h" is changed to "adjusting the speed of the peristaltic pump to control the upward flow rate of the acid leachate in the plexiglass column at 0.25 m / h". The other steps and conditions are the same as in Example 1.
[0059] Example 9 The steps and conditions are the same as in Example 1.
[0060] Example 10 The difference from Example 1 is that in step 2, "adjusting the speed of the peristaltic pump to control the upward flow rate of the acid leachate in the plexiglass column at 0.38 m / h" is changed to "adjusting the speed of the peristaltic pump to control the upward flow rate of the acid leachate in the plexiglass column at 0.51 m / h". The other steps and conditions are the same as in Example 1.
[0061] Example 11 The difference from Example 1 is that in step 2, "adjusting the speed of the peristaltic pump to control the upward flow rate of the acid leachate in the plexiglass column at 0.38 m / h" is changed to "adjusting the speed of the peristaltic pump to control the upward flow rate of the acid leachate in the plexiglass column at 0.64 m / h". The other steps and conditions are the same as in Example 1.
[0062] Example 12 The difference from Example 1 is that in step 2, "adjusting the speed of the peristaltic pump to control the upward flow rate of the acid leachate in the plexiglass column at 0.38 m / h" is changed to "adjusting the speed of the peristaltic pump to control the upward flow rate of the acid leachate in the plexiglass column at 0.76 m / h". The other steps and conditions are the same as in Example 1.
[0063] Comparing Examples 7-12, the effect of different upward flow velocities of the leaching solution in the plexiglass column on the acid leaching of uranium ore was analyzed to determine the optimal acidity. The changes in uranium concentration in the storage tank under different upward flow velocities of the leaching solution are shown below. Figure 4 As shown, the acidity changes are as follows: Figure 5 As shown.
[0064] Figure 4 and Figure 5Experimental results show that the upflow velocity has a significant regulatory effect on both uranium leaching and acid consumption. For example... Figure 4 As shown, in terms of uranium leaching, increasing the upflow rate can simultaneously accelerate the leaching rate and increase the final leaching concentration. At the end of the reaction, the final uranium concentration of the higher flow rate group (≥0.38 m / h) stabilizes in a higher range (0.32-0.375 g / L).
[0065] like Figure 5 As shown, in terms of acid consumption, increasing the flow rate significantly enhances the mass transfer process, resulting in a faster and more thorough decrease in acidity. Ultimately, the steady-state acidity is negatively correlated with the flow rate. However, when the flow rate increases to 0.64 m / h and 0.76 m / h, the two acidity curves tend to overlap in the later stages of the reaction, indicating that at excessively high flow rates, mass transfer is no longer the limiting factor, and the reaction rate is instead limited by the chemical kinetics of the solid-liquid interface itself.
[0066] When the flow rate is higher than 0.38 m / h (e.g., above 0.64 m / h), the leaching effect is not significantly improved. When the flow rate is lower than 0.38 m / h, neither the leaching rate nor the final concentration is optimal. Considering both the leaching effect and reagent efficiency, 0.38 m / h is selected as the optimal acidification rising flow rate.
[0067] Example 13 Bioleaching experiment of 1 kg uranium ore Step 1: Construct the experimental setup The experimental setup consists of an acrylic column (h=40cm, Φ=7cm, φ=6cm), a Lange BT100-3J peristaltic pump, silicone pump tubing, PVC tubing, and a polyethylene tank. The acrylic column has an inlet at the bottom and an outlet at the top. A permeate layer (approximately 2cm thick) is laid at the bottom of the column, filled with 1kg of uranium ore. The leaching solution operates in a bottom-in, top-out manner. The prepared biological leaching solution is placed in the polyethylene tank (storage tank). The PVC tubing connecting the peristaltic pump is positioned below the water surface in the polyethylene tank (ensuring continuous inflow). Driven by the peristaltic pump, the solution enters through the inlet at the bottom of the acrylic column and finally flows back into the polyethylene tank through the outlet at the top.
[0068] Step 2: Uranium ore leaching Using the adsorption tail liquid from the adsorption tower as the base solution, a bioleaching bacterial solution was prepared in a polyethylene tank. Specific parameters were set as follows: bacterial solution dosage 2L, ferric iron concentration 1.0g / L, and acidity 5g / L. A peristaltic pump was used to pump the bioleaching bacterial solution from the bottom of the polyethylene tank into an plexiglass column. The pump speed was adjusted to control the upward flow velocity of the bioleaching bacterial solution in the plexiglass column at 0.64m / h. 1kg of uranium ore was subjected to bioleaching for 48 hours. During the bioleaching process, the acidity, uranium concentration, and ferrous iron concentrations in the polyethylene tank were periodically measured at initial, 1h, 2h, 4h, 8h, 12h, 24h, 36h, and 48h intervals.
[0069] Example 14 The difference from Example 13 is that in step 2, "2L of bacterial solution added" is changed to "1L of bacterial solution added", while the other steps and conditions are the same as in Example 13.
[0070] Example 15 The difference from Example 13 is that in step 2, "2L of bacterial solution added" is changed to "3L of bacterial solution added", while the other steps and conditions are the same as in Example 13.
[0071] Example 16 The difference from Example 13 is that in step 2, "2L of bacterial solution added" is changed to "4L of bacterial solution added", while the other steps and conditions are the same as in Example 13.
[0072] Example 17 The difference from Example 13 is that in step 2, "2L of bacterial solution added" is changed to "5L of bacterial solution added", while the other steps and conditions are the same as in Example 13.
[0073] Example 18 The difference from Example 13 is that in step 2, "2L of bacterial solution added" is changed to "6L of bacterial solution added", while the other steps and conditions are the same as in Example 13.
[0074] Comparing Examples 13-18, the effect of different liquid-to-solid ratios of bacterial solution and uranium ore on the bioleaching of uranium ore was analyzed to determine the optimal liquid-to-solid ratio. The changes in uranium concentration in the storage tank under different liquid-to-solid ratios are shown below. Figure 6 As shown, the acidity changes are as follows: Figure 7 As shown, Fe 3+ Total consumption as Figure 8 As shown.
[0075] like Figure 6As shown, the uranium leaching process exhibits three stages under different solid-liquid ratio systems: rapid enrichment (0-10 h), slow growth (10-30 h), and dynamic equilibrium (30-50 h). The liquid-solid ratio significantly affects the leaching rate and the final uranium leaching concentration. At a liquid-solid ratio of 1:1, the leaching kinetics are the fastest, with the uranium concentration rapidly increasing to 0.35 g / L within 10 hours, while the 1:6 system only increases to 0.08 g / L, a difference of 4.4 times. At equilibrium, the concentration in the 1:1 system stabilizes at 0.55 g / L, which is 3.67 times that of the 1:6 system. These data indicate that increasing the solid phase ratio (i.e., decreasing the liquid-solid ratio) can significantly accelerate the uranium leaching process.
[0076] like Figure 7 As shown, regarding acidity maintenance, by monitoring the evolution of acidity over time (0-48 h) in systems with different solid-liquid ratios (1:1 to 1:6), a selective threshold effect was found in the influence of the solid-liquid ratio on acidity: when the liquid-solid ratio ≥ 2:1, the acidity of the system remained stably maintained within a narrow range of 5.0-5.2 g / L with minimal fluctuations (RSD < 3%). Only the system with a liquid-solid ratio of 1:1 exhibited different low-acid steady-state characteristics (stable around 4.8 g / L), and showed statistically significant differences compared to other systems. This also indicates that within the experimental parameter range, the regulatory effect of the solid-liquid ratio on acidity only shows significant differences when the solid phase accounts for more than 50%.
[0077] like Figure 8 As shown, in terms of oxidant utilization, Fe³ + The consumption pattern is synergistic with uranium leaching. In systems with a liquid-to-solid ratio of 2:1 to 6:1, Fe³⁺ + Consumption increased steadily over time, reaching 1.18-1.32 g / L after 48 hours. The Fe³⁺ content in the 1:1 liquid-to-solid ratio system was... + The consumption kinetics are significantly lagging, with its consumption rate constant being only 58% of that of other systems, and the final consumption is also low, indicating that an excessively high solid phase ratio may inhibit the efficiency of interfacial mass transfer and oxidation reaction.
[0078] Since the uranium concentration in the leaching solution cannot accurately reflect the leaching effect of uranium ore due to different liquid-solid ratios, the total amount of uranium leached during the reaction process was recorded for different liquid-solid ratios. The initial total amount of uranium under all liquid-solid ratio conditions was 0.02 g. The total amount of uranium leached under different liquid-solid ratios is shown in Table 2.
[0079] Table 2 Total uranium leached under different liquid-solid ratios As shown in Table 2, the total amount of uranium leached at each liquid-solid ratio increases significantly with time. After 48 hours of reaction, the total uranium leached at liquid-solid ratios 1-6 are 0.49 g, 0.58 g, 0.60 g, 0.64 g, 0.65 g, and 0.66 g, respectively. The total amount of leached uranium gradually increases with the increase of the liquid-solid ratio, indicating a higher leaching efficiency. This is because a higher liquid-solid ratio provides more liquid to contact and extract uranium from the solid, thus improving leaching efficiency. However, blindly increasing the liquid-solid ratio does not improve uranium ore leaching efficiency; instead, it increases the amount of liquid required for subsequent processing, increasing operating costs. Considering factors such as cost, equipment requirements, and ease of operation, liquid-solid ratio 2 is selected as the optimal leaching liquid-solid ratio.
[0080] Example 19 The difference from Example 13 is that in step 2, "the acidity of the leaching solution is 5 g / L" is changed to "the acidity of the leaching solution is 4 g / L", while the other steps and conditions are the same as in Example 13.
[0081] Example 20 The steps and conditions are the same as in Example 13.
[0082] Example 21 The difference from Example 13 is that in step 2, "the acidity of the leaching solution is 5 g / L" is changed to "the acidity of the leaching solution is 6 g / L", while the other steps and conditions are the same as in Example 13.
[0083] Example 22 The difference from Example 13 is that in step 2, "the acidity of the leaching solution is 5 g / L" is changed to "the acidity of the leaching solution is 7 g / L", while the other steps and conditions are the same as in Example 13.
[0084] Example 23 The difference from Example 13 is that in step 2, "the acidity of the leaching solution is 5 g / L" is changed to "the acidity of the leaching solution is 8 g / L", while the other steps and conditions are the same as in Example 13.
[0085] Example 24 The difference from Example 13 is that in step 2, "the acidity of the leaching solution is 5 g / L" is changed to "the acidity of the leaching solution is 9 g / L", while the other steps and conditions are the same as in Example 13.
[0086] Comparing Examples 19-24, the effect of leaching bacterial solution acidity on the bioleaching of uranium ore was analyzed to determine the optimal leaching bacterial solution acidity. The changes in uranium concentration in the storage tank under different acidity conditions of the leaching bacterial solution are shown below. Figure 9 As shown, the acidity changes are as follows: Figure 10 As shown, Fe 3+ Total consumption asFigure 11 As shown.
[0087] like Figure 9 As shown, the uranium concentration increase exhibits a typical two-stage kinetic characteristic. In the initial reaction stage (0-10 h), the uranium concentration rises rapidly, with an average growth rate of 0.04 g / (L·h). After entering the intermediate reaction stage (10-50 h), the growth rate slows significantly to 0.008 g / (L·h), presumably related to the decrease in effective reactant concentration and diffusion limitation effect. Although the system with higher initial acidity generally has higher absolute uranium concentrations at all time points, the final leaching concentrations under different acidity conditions differ very little (difference <0.12 g / L). This also indicates that there is a significant threshold effect of acidity on uranium leaching efficiency; when the acidity meets the basic requirements, further increases in acidity have limited effect on improving the final uranium leaching rate.
[0088] like Figure 10 As shown, each system exhibits extremely strong buffering capacity in terms of acidity stability. During the leaching process lasting up to 48 hours, the fluctuation range of all tested acidities was strictly controlled within ±0.2 g / L, which also indicates that the initial acidity setting directly determines the stable acidity value of the system and that the process has good controllability.
[0089] like Figure 11 As shown, in terms of oxidant utilization, Fe³ + The consumption pattern of Fe³⁺ is closely related to acidity. The higher the acidity, the more Fe³⁺ is consumed. + The faster the consumption rate, the lower the final residual concentration, indicating that increasing acidity effectively promotes the consumption of Fe³⁺. + The kinetics of uranium dissolution reaction with oxidant. However, combined with uranium leaching data, it can be seen that excessively high Fe³⁺... + The consumption rate did not lead to a linear increase in the leaching rate.
[0090] After comprehensively comparing leaching effects, reagent consumption, and process stability, an acidity of 4 g / L in the bacterial solution was selected as the optimal condition for the bioleaching stage. At this acidity, the reaction system can maintain sufficient H₂O. + Concentration to prevent Fe³ + Hydrolysis and precipitation ensure microbial activity and achieve efficient uranium oxidative leaching, with a final leaching rate comparable to that under higher acidity (9 g / L) conditions. Further increasing the acidity, while slightly accelerating the initial kinetics, significantly increases unnecessary acid consumption and contributes little to improving the final total leaching yield.
[0091] Example 25 The difference from Example 19 is that in step 2, "the concentration of ferric iron in the bacterial solution is 1.0 g / L" is changed to "the concentration of ferric iron in the bacterial solution is 0.6 g / L", while the other steps and conditions are the same as in Example 19.
[0092] Example 26 The difference from Example 19 is that in step 2, "the concentration of ferric iron in the bacterial solution is 1.0 g / L" is changed to "the concentration of ferric iron in the bacterial solution is 1.6 g / L", while the other steps and conditions are the same as in Example 19.
[0093] Example 27 The difference from Example 19 is that in step 2, "the concentration of ferric iron in the bacterial solution is 1.0 g / L" is changed to "the concentration of ferric iron in the bacterial solution is 2.6 g / L", while the other steps and conditions are the same as in Example 19.
[0094] Example 28 The difference from Example 19 is that in step 2, "the concentration of ferric iron in the bacterial solution is 1.0 g / L" is changed to "the concentration of ferric iron in the bacterial solution is 3.6 g / L", while the other steps and conditions are the same as in Example 19.
[0095] Example 29 The difference from Example 19 is that in step 2, "the concentration of ferric iron in the bacterial solution is 1.0 g / L" is changed to "the concentration of ferric iron in the bacterial solution is 4.6 g / L". The other steps and conditions are the same as in Example 19.
[0096] Example 30 The difference from Example 19 is that in step 2, "the concentration of ferric iron in the bacterial solution is 1.0 g / L" is changed to "the concentration of ferric iron in the bacterial solution is 5.6 g / L". The other steps and conditions are the same as in Example 19.
[0097] Comparing Examples 25-30, the effect of ferric iron concentration in the leaching bacterial solution on the bioleaching of uranium ore was analyzed to determine the optimal ferric iron concentration. The changes in uranium concentration in the storage tank under different ferric iron concentrations in the leaching bacterial solution are shown below. Figure 12 As shown, the acidity changes are as follows: Figure 13 As shown, Fe 3+ Total consumption as Figure 14 As shown.
[0098] like Figure 12 As shown, Fe³ + The effect of concentration on uranium leaching kinetics becomes more pronounced over time. In the initial stage of the reaction (0-10 h), the leaching rates at different concentrations are similar; after 10 hours, the differences widen significantly, with the initial Fe³⁺ concentration showing a greater impact. + The higher the concentration in the experimental group, the faster the uranium concentration increased, and the significantly higher the final concentration value was reached. These results indicate that Fe³⁺ + The initial supply is a crucial factor affecting the kinetics of the later stages of leaching and the final upper limit of uranium concentration leaching.
[0099] like Figure 13 As shown, increasing Fe³ +Concentration affects the acid-base balance and self-consumption of the system. At lower ferric concentrations (0.6 g / L and 1.6 g / L), the acidity decreases relatively slowly, and the curve is relatively flat. As the ferric concentration increases (2.6 g / L, 3.6 g / L, 4.6 g / L, and 5.6 g / L), the rate of acidity decrease gradually accelerates, and the curve becomes steeper. This indicates that Fe³⁺… + The higher the concentration, the faster the acidity of the system decreases, and the lower the final acidity value. This is related to Fe³⁺. + Hydrolysis consumes H + It is related to the complex reactions that produce acid from the oxidation of sulfide minerals.
[0100] like Figure 14 As shown, when the concentrations of ferric iron (Fe³⁺) were 0.6 g / L, 1.6 g / L, and 2.6 g / L, the overall decreasing trend of Fe³⁺ concentration was relatively stable. When the concentrations were 3.6 g / L, 4.6 g / L, and 5.6 g / L, the initial decreasing rate of Fe³⁺ concentration was faster, followed by a gradual plateau. The curves showed a rapid decrease in concentration from 0 to 10 hours, especially the curves with high initial concentrations (e.g., 5.6 g / L and 4.6 g / L), where the decrease was significant. The decreasing rate slowed from 10 to 30 hours, but still maintained a certain decreasing trend. From 30 to 48 hours, the decreasing trend further slowed, gradually becoming flat, indicating a decrease in reaction rate and approaching equilibrium. These results collectively demonstrate that providing sufficient Fe³⁺... + It is the basis for maintaining continuous oxidative leaching capacity.
[0101] Based on the above analysis, improving Fe 3+ Concentration helps increase uranium leaching concentration, but when Fe... 3+ When the concentration is too high (e.g., >2.6 g / L), acid consumption increases significantly, leading to higher operating costs and a slower rate of increase in uranium leaching rate (marginal benefit). Based on the reaction equation UO2 + Fe2(SO4)3 → UO2SO4 + 2FeSO4, the amount of ferric iron consumed, and the amount of uranium ore leached, when the ferric iron concentration is 1.6 g / L, the ferric iron consumption after the reaction is 0.82 g / L, and the uranium ore leaching amount is 0.26 g / L. This calculates to approximately 0.398 g of tetravalent uranium consumed during the reaction. Considering the tetravalent uranium content and iron consumption, a ferric iron concentration of 1.0 g / L ensures a high uranium leaching rate while avoiding excessive iron ions that lead to ineffective acid consumption and increased costs. Therefore, 1.0 g / L is the optimal concentration for the leaching stage. 3+ concentration.
[0102] Example 31 The difference from Example 19 is that in step 2, "adjusting the speed of the peristaltic pump to control the upward flow rate of the bioleaching solution in the plexiglass column at 0.64 m / h" is changed to "adjusting the speed of the peristaltic pump to control the upward flow rate of the bioleaching solution in the plexiglass column at 0.13 m / h". The other steps and conditions are the same as in Example 19.
[0103] Example 32 The difference from Example 19 is that in step 2, "adjusting the speed of the peristaltic pump to control the upward flow rate of the bioleaching solution in the plexiglass column at 0.64 m / h" is changed to "adjusting the speed of the peristaltic pump to control the upward flow rate of the bioleaching solution in the plexiglass column at 0.25 m / h". The other steps and conditions are the same as in Example 19.
[0104] Example 33 The difference from Example 19 is that in step 2, "adjusting the speed of the peristaltic pump to control the upward flow rate of the bioleaching solution in the plexiglass column at 0.64 m / h" is changed to "adjusting the speed of the peristaltic pump to control the upward flow rate of the bioleaching solution in the plexiglass column at 0.38 m / h". The other steps and conditions are the same as in Example 19.
[0105] Example 34 The difference from Example 19 is that in step 2, "adjusting the speed of the peristaltic pump to control the upward flow rate of the bioleaching solution in the plexiglass column at 0.64 m / h" is changed to "adjusting the speed of the peristaltic pump to control the upward flow rate of the bioleaching solution in the plexiglass column at 0.51 m / h". The other steps and conditions are the same as in Example 19.
[0106] Example 35 The steps and conditions are the same as in Example 19.
[0107] Example 36 The difference from Example 19 is that in step 2, "adjusting the speed of the peristaltic pump to control the upward flow rate of the bioleaching solution in the plexiglass column at 0.64 m / h" is changed to "adjusting the speed of the peristaltic pump to control the upward flow rate of the bioleaching solution in the plexiglass column at 0.76 m / h". The other steps and conditions are the same as in Example 19.
[0108] Comparing Examples 31-36, the effect of the upward flow velocity of the leaching bacterial solution on the bioleaching of uranium ore was analyzed to determine the optimal upward flow velocity. The changes in uranium concentration in the storage tank under different upward flow velocities of the leaching bacterial solution are shown below. Figure 15 Fe shown 3+ Total consumption as Figure 16 As shown.
[0109] like Figure 15As shown, the upward flow rate is a key parameter controlling the uranium leaching rate and the final leaching concentration. The flow rate is significantly positively correlated with the leaching efficiency: at lower flow rates (≤0.25 m / h), the uranium concentration increases slowly; when the flow rate increases to 0.38 m / h and above, the leaching rate accelerates significantly, and the final uranium concentration increases with increasing flow rate. These results indicate that increasing the flow rate enhances the mass transfer process between the leaching solution and ore particles, accelerating the dissolution and elution of uranium.
[0110] like Figure 16 As shown, the upward flow velocity significantly affects Fe³ + Consumption of (primary oxidant). At lower upflow rates (0.13 m / h), the Fe³⁺ concentration decreased from approximately 2.25 g / L at 0 hours to 1.5 g / L at 48 hours, with the Fe³⁺ concentration higher at the same time points compared to other flow rates; as the upflow rate increased (from 0.25 m / h to 0.76 m / h), the Fe³⁺ concentration decreased. + The faster the concentration decreases, the lower the remaining Fe³⁺ concentration at the end of the reaction. This is because a higher flow rate promotes the Fe³⁺ concentration by enhancing fluid turbulence and renewing the solid-liquid interface. + Transport to the ore surface and its consumption efficiency in oxidation reactions.
[0111] Combined changes in uranium concentration and Fe 3+ Regarding total consumption, when the flow rate reaches 0.38 m / h, it can effectively overcome the internal diffusion resistance of the solid product layer, ensuring the smooth progress of the core reaction steps. At this point, the uranium leaching rate is close to the high-stability range. Furthermore, further significantly increasing the flow rate (e.g., to 0.76 m / h) has limited effect on improving the final leaching effect, but it will increase the energy consumption and operating costs of the circulation system. Therefore, 0.38 m / h is the optimal flow rate for achieving both leaching efficiency and operating costs.
[0112] Example 37 Biological leaching experiment of 120kg uranium ore Step 1: Construct the experimental setup The experimental setup mainly includes a polyethylene (PE) box, a polyethylene (PE) cylinder, a peristaltic pump, silicone pump tubing, and PVC tubing. The PE box, measuring 60*60*60cm, serves as the uranium ore leaching container. A percolation layer (pebbles, 3-7cm in diameter, with an 8.3% slope) is laid at the bottom of the box, upon which 120kg of uranium ore is placed. A liquid exchange port is located on the outer side of the bottom of the box. A polyethylene (PE) cylinder (d=15cm) with openings at both ends stands near the box wall, penetrating both the percolation layer and the uranium ore layer. Square strips (5cm high, 2cm wide) are evenly distributed on the bottom wall of the cylinder as percolation openings. Under gravity, the liquid in the box enters the cylinder through these square openings. The liquid in the cylinder is then transported by the peristaltic pump to the ore surface for gravity-driven percolation, forming a circulation loop. The entire circulation loop is constructed of PVC tubing (the peristaltic pump tubing uses silicone tubing).
[0113] Step 2, Acidification Stage After the apparatus was filled with ore, the acidifying solution was prepared based on the optimal operating parameters for a leaching experiment with 1 kg of uranium ore. The acidification solution had an acidity of 10 g / L and an upward flow rate of 200 r / min. The prepared acidifying solution was slowly added from the top of the cylindrical chamber, ensuring that it reached the surface of the ore layer from the bottom of the cylinder, through the bottom of the chamber, and over the ore layer. When the leaching solution completely submerged the ore and there was a gap between the liquid level and the top of the cylinder, the amount of leaching solution added was recorded. The pre-set peristaltic pumps (two pumps per chamber, each set to 100 r / min) were then turned on to begin the acidification experiment. After 4 hours of continuous operation, the acidification experiment ended, and samples of the original acidifying solution and the effluent after 4 hours were taken for analysis.
[0114] Step 3, Bacterial Immersion Stage The leaching solution was prepared based on the optimal operating parameters for a 1kg uranium ore leaching experiment. The acidity of the leaching solution was 4g / L, the ferric iron concentration was 1.6g / L, and the leaching flow rate was 200r / min. The prepared leaching solution was added to the tank according to the acidification procedure. When the leaching solution completely submerged the ore and the liquid level was slightly below the top of the cylinder, the amount of leaching solution added was recorded. The pre-set peristaltic pumps (two pumps per tank, each set to 100r / min) were then turned on to begin the leaching experiment. During the leaching process, samples were taken from the top of the cylinder at intervals of 0h, 4h, 8h, 12h, 24h, 36h, and 48h. After 48h, the solution was replaced (using the same leaching solution as the initial solution). When the uranium concentration change was less than 0.1g / L after 48h, the solution replacement interval was adjusted to 24h, with samples taken at intervals of 0h, 4h, 8h, and 12h during this period. The leaching experiment ended when the change in uranium concentration over 24 hours was less than 0.01 g / L. The volume of liquid exchange and the leached uranium concentration at each stage of the leaching system are shown in Table 3.
[0115] Table 3. Uranium leaching in the bacterial leaching system Example 38 Leaching experiment of 120kg uranium ore adsorption tailings The steps are the same as those in Example 38, specifically steps 1 and 2.
[0116] Step 3, Bacterial Immersion Stage The adsorption tailings solution was prepared based on the optimal operating parameters for a leaching experiment using 1 kg of uranium ore. The acidity of the adsorption tailings solution was 4 g / L, and the upward flow rate was 200 r / min. The prepared leaching solution was added to the tank according to the acidification procedure. When the leaching solution completely submerged the ore and the liquid level was slightly below the top of the cylinder, the amount of leaching solution added was recorded. The pre-set peristaltic pumps (two pumps per tank, each set to 100 r / min) were then turned on to begin the adsorption tailings leaching experiment. During the leaching process, samples were taken from the top of the cylinder at intervals of 0 h, 4 h, 8 h, 12 h, 24 h, 36 h, and 48 h. After 48 h, the solution was replaced (using the same leaching solution as the initial solution). When the change in uranium concentration after 48 h was less than 0.1 g / L, the replacement interval was adjusted to 24 h, with samples taken at intervals of 0 h, 4 h, 8 h, and 12 h during this period. The leaching experiment of the adsorption tail liquid ended when the change in uranium concentration over 24 hours was less than 0.01 g / L. The volume of liquid exchange and the leached uranium concentration at each stage in the adsorption tail liquid leaching system are shown in Table 4.
[0117] Table 4. Leaching status of the adsorption tail liquid leaching system Comparing Examples 37 and 38, the changes in uranium concentration during the bacterial leaching stage and the tailings leaching stage were compared to analyze the leaching effect of the bacterial leaching system on uranium ore. The changes in uranium concentration in the bacterial leaching system and the tailings leaching system are as follows: Figure 17 As shown.
[0118] from Figure 17As can be seen, during the bacterial leaching process, the uranium concentration in the initial bacterial solution rapidly increased from 0 g / L to approximately 0.75 g / L; the uranium concentration in the tailings solution increased from 0 g / L to approximately 0.5 g / L. In the mid-leaching stage, the uranium concentration in the bacterial solution reached a plateau after 64 hours, decreased slightly after 128 hours, and then increased again; the uranium concentration in the tailings solution continued to increase after 64 hours, reaching approximately 0.25 g / L after 128 hours, and then remained relatively stable. In the late-leaching stage, the uranium concentration in the bacterial solution began to decrease after 192 hours, eventually approaching 0 g / L; the uranium concentration in the tailings solution also decreased slightly after 192 hours, eventually stabilizing at approximately 0.1 g / L. Throughout the process, the uranium concentration generally increased first and then decreased, indicating that uranium generation and consumption differed significantly at different stages.
[0119] The uranium concentration leached in the bacterial leaching system changed as follows from stage one to stage nine: 1.26 g / L, 0.76 g / L, 0.74 g / L, 0.49 g / L, 0.54 g / L, 0.41 g / L, 0.27 g / L, 0.28 g / L, and 0.37 g / L, with a total uranium leaching concentration of 5.12 g / L. The uranium concentration leached in the tailings leaching system changed as follows from stage one to stage nine: 0.46 g / L, 0.48 g / L, 0.74 g / L, 0.10 g / L, 0.36 g / L, 0.44 g / L, 0.11 g / L, 0.13 g / L, and -0.2 g / L, with a total uranium leaching concentration of 2.62 g / L. In the absence of an oxidant, the total uranium concentration leached in the tailings leaching system was 2.50 g / L less than that in the bacterial leaching system. Throughout the leaching process, the uranium concentration in the bacterial solution remained higher than that in the tailings solution. This is related to the higher activity of the microorganisms in the bacterial solution, allowing for faster uranium leaching. The changes in uranium concentration at different stages may reflect variations in microbial metabolic activity and environmental conditions at different stages of the leaching process.
[0120] Table 5 shows the solid-liquid uranium equilibrium state in the tailings leaching system, and Table 6 shows the ore grade of the ore and the raw ore after the reaction of the bacterial leaching system and the tailings leaching system.
[0121] Table 5 Solid-liquid uranium equilibrium state in the tailings leaching system Table 6. Ore grades after leaching using the bacterial leaching system and the tailings leaching system. As shown in Table 5, in the tail liquid leaching system, the solid phase uranium grade and liquid phase uranium concentration gradually decrease with increasing stage, indicating that uranium is more easily transferred from the solid phase to the liquid phase in the initial stage. The stage equilibrium increases with increasing stage, indicating that over time, the residual amount of uranium in the solid phase gradually decreases, and the concentration of uranium in the liquid phase reaches saturation.
[0122] As shown in Table 6, the ore grade statistics for different ores indicate that the leaching rate of the integrated bacterial-liquid bioleaching method reaches 92.9% after 316 hours, and the leaching rate of the tailings integrated bioleaching method reaches 85.2% after 316 hours. Compared with the traditional acid spraying method that takes about 100 days, this technology improves the production efficiency by nearly 10 times.
[0123] The reason why bacterial leaching systems can improve uranium leaching rates is that they contain highly active microorganisms (such as *Thiobacillus ferrooxidans*), which effectively oxidize sulfides in the ore, generating sulfate and ferrous ions, thereby promoting uranium dissolution. In contrast, the microbial activity in tailings leaching systems is lower, resulting in a slower sulfide oxidation rate and affecting uranium leaching efficiency. The microorganisms in the bacterial solution, after selection and domestication, can maintain high activity under high fluoride, low temperature, and high acidity environments, continuously providing strong oxidants. These oxidants can dissolve poorly soluble uranium... 4+ Oxidized into easily soluble U 6+ This allows the bacterial leaching system to maintain high leaching efficiency under various environmental conditions. However, the tailings leaching system lacks an effective oxidant, resulting in lower uranium leaching efficiency.
[0124] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.
Claims
1. A bioleaching method for hard-rock uranium deposits, characterized in that, include: S1. Construct a bio-heap leaching device comprising a leaching column, an acidification solution storage tank, a biological bacterial solution storage tank, an acidification solution circulation pump, and a leaching solution circulation pump; wherein, the leaching column adopts a bottom-in, top-out operation mode: the leaching column has an inlet at the bottom and an outlet at the top, and a permeation layer is laid at the bottom of the column, with uranium ore filled on the permeation layer; when the device is running, the liquid in the storage tank is pumped into the leaching column from the bottom by the circulation pump, and finally flows back to the corresponding storage tank from the top outlet; S2. Prepare acidifying solution in acidifying solution storage tank, and pump the acidifying solution into leaching column containing uranium ore through circulation pump. Set the rising flow rate of acidifying solution in leaching column and acidification reaction time to perform closed-loop circulation leaching of uranium ore; wherein, the acidifying solution comes from the adsorption tailings of CNNC Shaoguan Jinyuan Uranium Industry Hydrometallurgical Plant. S3. In the biological bacterial solution storage tank, the leaching bacterial solution is prepared based on the adsorption tailings of Jinyuan Uranium Industry Hydrometallurgical Plant. The leaching bacterial solution is pumped into the leaching column that has completed acidification pretreatment by a circulation pump. The upward flow rate of the leaching bacterial solution and the leaching time are set to perform closed-loop circulation leaching of the acidified uranium ore. The key process parameters of the leaching bacterial solution include the iron concentration of the bacterial solution, the acidity of the bacterial solution, and the liquid-solid ratio of the bacterial solution to the uranium ore.
2. The method according to claim 1, characterized in that, The acidity of the acidification solution in step S2 is 4-39 g / L.
3. The method according to claim 1, characterized in that, The upward flow rate of the acidified liquid in step S2 is 0.13-0.76 m / h.
4. The method according to claim 1, characterized in that, The acidification reaction time in step S2 is 2-4 h.
5. The method according to claim 1, characterized in that, The biological bacterial solution mentioned in step S3 is obtained by using the adsorption tailings from the hydrometallurgical plant of CNNC Shaoguan Jinyuan Uranium Industry as a culture medium and through long-term domestication of functional bacterial groups. The main dominant bacteria in the biological bacterial solution are acidophilic ferrooxidizing thiobacillus, iron-oxidizing Leptospira, and acidophilic thiooxidizing thiobacillus.
6. The method according to claim 1, characterized in that, In step S3, the liquid-to-solid ratio of the leaching solution to the uranium ore is 1-6:1 L / kg.
7. The method according to claim 1, characterized in that, The acidity of the leaching solution in step S3 is 4-9 g / L.
8. The method according to claim 1, characterized in that, The concentration of ferric iron in the leaching solution in step S3 is 0.6-5.6 g / L.
9. The method according to claim 1, characterized in that, The upward flow rate of the leaching solution in step S3 is 0.13-0.76 m / h.
10. The method according to claim 1, characterized in that, The leaching reaction time in step S3 is 48-316 h.