A separate acidification process for weakly confined mining areas in acid in-situ leaching mines

Abstract

The present invention belongs to the acidification process, and particularly relates to a separate acidification process for a weakly confined mining area in an acid-in-situ leaching mine. A separate acidification process for a weakly confined mining area in an acid-in-situ leaching mine, which includes the following steps: the first step: pumping and injecting clear water in a cycle; the second step: low-acid acidification; the third step: high-acid acidification; the fourth step: integrally connecting to the production system. The remarkable effects of the present invention are as follows: (1) During the acidification of a single mining area, the acidity of the leaching agent in the mining area can be flexibly adjusted. (2) Filtration of the extracted liquid during the acidification cycle stage is achieved, reducing the probability of secondary blockage caused by clay impurities entering the ore layer. (3) By adding clear water, the injection volume of the acidification leaching agent is increased, while the acidification intensity is enhanced and the groundwater level in the weakly confined mining area is raised. (4) When the uranium concentration in the extracted liquid of a single well reaches the design index, it can be connected to the production system at any time, and other pumping and injection units continue to cycle and acidify.

Description

Technical Field

[0001] The invention belongs to the acidification process, and particularly relates to a separate acidification process for a weak confined mining area in an acid leaching uranium mine. Background Art

[0002] During the in-situ leaching uranium production process, it is necessary to acidify the mining area and connect it to the production system when the remaining acid reaches the design index. In the previous acidification process before the mining area is put into operation, direct acidification and advanced acidification are mainly used. The advantage of direct acidification is that it can ensure the pumping and injection balance during the acidification period or the injection flow rate is slightly greater than the pumping flow rate at the initial stage; the disadvantage is that in the initial stage of acidification, the water pumped out from the pumping holes is mainly the original groundwater, and its uranium concentration is low, which does not meet the requirements of the hydrometallurgy process. The advantage of advanced acidification is that the acidification time is short, the acid consumption can be saved, and the uranium concentration in the leachate will quickly reach the industrial required concentration; the disadvantage is that precipitates may be generated during the sufficient reaction between minerals and high acid, which is not conducive to leaching, and it is not suitable for low-permeability ore deposits. Summary of the Invention

[0003] Aiming at the defects of the prior art, the invention provides a separate acidification process for a weak confined mining area in an acid leaching uranium mine.

[0004] The invention is realized as follows: A separate acidification process for a weak confined mining area in an acid leaching uranium mine, which includes the following steps:

[0005] The first step: Circulate the pumping and injection of clear water,

[0006] The second step: Acidify with low acid,

[0007] The third step: Acidify with high acid,

[0008] The fourth step: Integrally connect to the production system.

[0009] For the separate acidification process for a weak confined mining area in an acid leaching uranium mine as described above, the first step includes adding clear water through a buffer tank during this period, and replacing the filter bag when the filter pressure is close to the pipeline design pressure until the pumped-out liquid is basically clarified.

[0010] For the separate acidification process for a weak confined mining area in an acid leaching uranium mine as described above, the second step includes controlling the sulfuric acid addition amount through an electric control valve, continuously adding clear water through the clear water addition pipeline during maintaining the acidity of the injected liquid, and replacing the filter bag when the filter pressure is close to the pipeline design pressure.

[0011] For the separate acidification process for a weak confined mining area in an acid leaching uranium mine as described above, the second step includes maintaining the acidity of the injected liquid between 4 and 5 g / L.

[0012] An individual acidification process for a weakly confined mining area in an acid in-situ leaching mine as described above, wherein the condition for replacing the filter bag is that the pH of the extracted liquid from each pumping hole is ≤ 3.

[0013] An individual acidification process for a weakly confined mining area in an acid in-situ leaching mine as described above, wherein the third step includes controlling the sulfuric acid addition amount through an electric control valve to maintain the acidity of the injected liquid between 7 and 8 g / L. During this period, continue to add clear water through the clear water addition pipeline. When the pressure of the filter approaches the designed pipeline pressure, replace the filter bag. When the uranium concentration in a single hole meets the requirements for entering the production system, switch to the production system through a valve until the residual acid in the extracted liquid from 80% of the pumping holes is ≥ 2.5 g / L.

[0014] An individual acidification process for a weakly confined mining area in an acid in-situ leaching mine as described above, wherein the fourth step includes closing the individual acid mixing circulation system, stopping the addition of clear water, and integrating into the production system as a whole.

[0015] The remarkable effects of the present invention are as follows: (1) Realize the flexible adjustment of the acidity of the leaching agent in the mining area during the acidification of a single mining area. (2) Realize the filtration of the extracted liquid during the acidification circulation stage, reducing the probability of secondary blockage caused by muddy impurities entering the ore layer. (3) By adding clear water, increase the injection amount of the acidification leaching agent, while enhancing the acidification intensity, raise the groundwater level in the weakly confined mining area. (4) When the uranium concentration in the extracted liquid from a single hole reaches the designed index, it can be connected to the production system at any time, and other pumping and injection units continue to circulate for acidification. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 : Schematic structural diagram of the equipment for the individual acidification process in a weakly confined mining area of an acid in-situ leaching mine;

[0017] Figure 2 : Process flow of the individual acidification in a weakly confined mining area of an acid in-situ leaching mine

[0018] In the figure: 1. Main injection pipeline; 2. Injection pipeline pump; 3. Injection hole; 4. Liquid extraction collection pipeline for entering the production system; 5. Liquid extraction hole; 6. Main liquid extraction pipeline; 7. Filter; 8. Sulfuric acid delivery pipeline; 9. Dilute acid delivery pipeline; 10. Electric control valve; 11. Acid injection pump; 12. Sulfuric acid flowmeter; 13. Clear water addition pipeline; 14. Acid tank; 15. Heat release tank; 16. Buffer tank. DETAILED DESCRIPTION OF THE INVENTION

[0019] As Figure 1As shown in the figure, a heat release tank and a buffer tank are set up and connected to a sulfuric acid storage tank through a PE pipeline. An electric control valve is installed on the pipeline connecting the acid tank and the heat release tank to achieve remote automatic adjustment of the sulfuric acid flow rate. An acid injection pump is installed on the pipeline connecting the heat release tank and the buffer tank, and ball valves are installed at the front end and the rear end. Each pumping and injection hole in the mining area and the buffer tank are connected through a steel-plastic pipe or a 316L stainless steel pipe to form a circulation loop. A liquid pumping and collecting pipeline connected to the production system is laid and connected to each pumping hole to achieve flexible access of single-hole liquid pumping to the production system.

[0020] A separate acidification process for a weakly confined mining area in an acid leaching mine

[0021] Step 1: Clear water pumping and injection circulation. During this period, clear water is replenished through the buffer tank. When the pressure of the filter approaches the designed pipeline pressure, the filter bag is replaced until the pumped liquid is basically clarified.

[0022] Step 2: Low-acid acidification. The sulfuric acid addition amount is controlled through the electric control valve to maintain the acidity of the injected liquid during downward injection between 4 and 5 g / L. During this period, clear water is continuously replenished through the clear water addition pipeline. When the pressure of the filter approaches the designed pipeline pressure, the filter bag is replaced until the pH of the pumped liquid from each pumping hole is ≤ 3.

[0023] Step 3: High-acid acidification. The sulfuric acid addition amount is controlled through the electric control valve to maintain the acidity of the injected liquid during downward injection between 7 and 8 g / L. During this period, clear water is continuously replenished through the clear water addition pipeline. When the pressure of the filter approaches the designed pipeline pressure, the filter bag is replaced. When the uranium concentration of a single hole meets the requirements for entering the production system, it enters the production system through valve switching until the residual acid of the pumped liquid from 80% of the pumping holes is ≥ 2.5 g / L.

[0024] Step 4: Integrally connect to the production system. Shut down the separate acid preparation circulation system, stop replenishing clear water, and integrally connect to the production system.

Claims

1. An independent acidification process for a weakly confined mining area in an acid in-situ leaching mine, characterized in that, It includes the following steps: The first step: pumping and circulating clear water The second step: low-acid acidification The third step: high-acid acidification The fourth step: integrally connecting to the production system; The said first step includes adding clear water through a buffer tank during the process. When the pressure of the filter approaches the designed pipeline pressure, replace the filter bag until the extracted liquid is basically clear; The said second step includes controlling the dosage of sulfuric acid added through an electric control valve, continuously adding clear water through the clear water addition pipeline during maintaining the acidity of the injected liquid downward, and replacing the filter bag when the pressure of the filter approaches the designed pipeline pressure; The said second step includes maintaining the acidity of the injected liquid downward between 4 and 5 g / L; The condition for replacing the filter bag is that the pH of the extracted liquid from each extraction hole ≤ 3; The said third step includes controlling the dosage of sulfuric acid added through an electric control valve, maintaining the acidity of the injected liquid downward between 7 and 8 g / L, continuously adding clear water through the clear water addition pipeline during the process, replacing the filter bag when the pressure of the filter approaches the designed pipeline pressure, and switching to the production system through a valve when the uranium concentration of a single hole meets the requirements for entering the production system until the residual acid of the extracted liquid from 80% of the extraction holes ≥ 2.5 g / L; The said fourth step includes closing the separate acid addition circulation system, stopping adding clear water, and integrally connecting to the production system.

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