CN-117778770-B - Mineral seam dredging method in-situ leaching uranium mining process

Abstract

The invention relates to the technical field of uranium ore on-site leaching, in particular to a method for dredging a mineral seam in the uranium leaching process. The method comprises the steps of carrying out statistical analysis on uranium leaching rate, acid consumption and characteristic ion leaching performance according to ore properties, determining an acid consumption step, stopping pumping and injecting liquid when the pumping hole liquid extraction amount is reduced to be less than 20% of the acceptance water amount, injecting sulfuric acid solution into the pumping hole, wherein the sulfuric acid concentration corresponds to the acid concentration of the ith stage of the acid consumption step, closing the pumping hole after the sulfuric acid solution is stopped being injected, starting pumping and injecting liquid circulation, ending the dredging operation, and returning to execute the second step when the pumping hole liquid extraction amount is reduced to be less than 20% of the acceptance water amount again, and increasing the sulfuric acid solution concentration to the acid concentration corresponding to the (i+1) th stage of the acid consumption step when the next acid injection dredging operation is carried out. The invention ensures that the flow direction of the dredging agent is opposite to that of the leaching solution, achieves the purposes of dissolving and dredging the blocked mineral layer and recovering the liquid extraction and injection amount, and has wide application range without introducing other ions.

Inventors

• CHENG WEI
• HUO JIANDANG
• QUE WEIMIN
• CHEN XI
• LI PO
• ZHAO LIXIN

Assignees

• 核工业北京化工冶金研究院

Dates

Publication Date

20260512

Application Date

20220921

Claims (6)

1. 1. The mineral seam dredging method in the process of in-situ leaching uranium mining is characterized by comprising the following steps of: According to the property of the ore, carrying out statistical analysis on the uranium leaching rate, acid consumption and characteristic ion leaching performance of the ore to obtain a leaching agent acid concentration-uranium leaching rate-ore acid consumption relation curve, and determining an acid consumption step from the curve, wherein the leaching agent is sulfuric acid, and the acid concentration of the acid consumption step is gradually increased; stopping pumping and injecting liquid when the pumping amount of the pumping hole is reduced to below 20% of the water yield, and injecting sulfuric acid solution into the pumping hole, wherein the concentration of the sulfuric acid solution corresponds to the acid concentration of the ith stage of the acid consumption step; Step three, after stopping injecting the sulfuric acid solution, performing hole sealing operation on the hole; Step four, starting a liquid pumping and injecting cycle, and ending the dredging operation; If the extraction amount of the extraction hole is reduced to be below 20% of the acceptance water amount again, returning to execute the second step, and increasing the concentration of the sulfuric acid solution to the acid concentration corresponding to the (i+1) th stage acid consumption step when the acid injection dredging operation is carried out for the next time; i is an integer of 1 to 5; the second step further comprises the following steps: In the acid process in-situ leaching process, the ore layer is fully leached after acidification, the change of the pumping volume of the pumping hole is continuously monitored under the basically constant pumping capacity and power of the submersible pump, and when the pumping volume of the pumping hole is found to be reduced to below 20% of the acceptance water volume, the operation of the second step is carried out.
2. 2. The method for dredging mineral seam in the uranium leaching process according to claim 1, wherein in the second step, sulfuric acid solution is injected into the pumping hole according to a flow rate of 3-4 square/hour.
3. 3. The method for dredging mineral seam in the uranium leaching process according to claim 2, wherein in the second step, a sulfuric acid solution is continuously injected for 3-8 days according to permeability and sulfate ion migration rate.
4. 4. The method for dredging mineral seam in the uranium leaching process according to claim 1, wherein in the third step, the time for hole-closing operation is 20-30 hours.
5. 5. The method for dredging mineral seam in the process of in-situ leaching uranium mining according to claim 1, wherein the concentration of sulfuric acid solution injected at the last time is higher than that of sulfuric acid solution injected at the previous time.
6. 6. The method for dredging mineral seam in the process of in-situ leaching uranium mining according to claim 1, wherein when the acid concentration of the leaching agent is less than or equal to 10.1 g/L, three near-step rapid acid consumption steps exist in the ore, and the steps are as follows: step I, namely leaching the ore with acid consumption of 1.3-1.9 kg/t when the acid concentration is 1.5-2.3 g/L; Step II, leaching the ore with acid consumption of 6.2-8.8 kg/t when the acid concentration is 3.2-7.6 g/L; Step III, leaching the ore with acid consumption of 14.3-15.2 kg/t when the acid concentration is 8.0-10.1 g/L; Above the step III, the acid consumption is more than 15.2kg/t ore when the concentration of leached acid is more than 10.1 g/L.

Description

Mineral seam dredging method in-situ leaching uranium mining process Technical Field The invention relates to the technical field of uranium ore on-site leaching, in particular to a mineral seam dredging method in the uranium leaching process. Background In the acid process in-situ leaching process, sulfuric acid and ore react chemically, ions such as iron, aluminum, calcium and uranium migrate into the solution, sulfuric acid is continuously consumed in the solution migration process, the pH value of the solution changes, and partial metal ions are hydrolyzed and precipitated. These precipitates separate from the liquid phase and adhere to the surface of the rock in the seam, causing chemical blockages. At the same time, some fine fraction solid particles such as rock fines reduce the permeability of the seam. Aiming at the problem of the reduction of the liquid extraction and injection amount caused by the blockage of a mineral deposit in the uranium mining process by an acid method, the method generally adopted at present comprises the means of air well flushing, piston well flushing, chemical well flushing and the like for dredging the mineral deposit. The air well flushing comprises air compressor well flushing, air compression well flushing and the like, and refers to a well flushing method taking compressed air provided by an air compressor as well flushing medium, which is one of the most common well flushing methods in the prior art, and is generally applicable to drilling in various well depths, water volumes and construction processes or production. The piston well flushing structure adopts the single-acting and double-acting iron piston structures so far, the wooden piston is basically eliminated in the current market, and the rubber of the piston is a coal mine conveyer belt. If the pistons are connected by a drill rod, the outer diameter of the rubber is larger than the inner diameter of the well pipe is 3-5 mm. For acid process in-situ leaching mines, chemical well washing generally adopts hydrochloric acid, hydrofluoric acid or compound acid for well washing. The cleaning range is large relative to the air compressor and the piston, and the micro-pickling hole is a hole cleaning method that hydrochloric acid injected into a plugged drilling hole is used for carrying out chemical reaction with bare limestone or other plugs in the drilling hole, and soluble CaCl 2 is changed into a solution, CO 2 escapes in a gaseous state, so that carbonate rock is dissolved by the hydrochloric acid, and water guide cracks and pores in a limestone stratum are corroded and expanded, so that a water-bearing layer waterway is smooth. The dilute hydrochloric acid can erode the blockage and the chlorine radical can not form new sediment, so that the method is suitable for blocking the formation of alkaline or weak acid sediment. The hydrofluoric acid is generally used for flushing the well, sulfuric acid and ammonium bifluoride are added into a to-be-cleaned drilling hole, after the hole is closed for 3-5 days, the flushing liquid is washed out by an air compressor, so that the blocked mineral seam is dredged. The strong corrosion of hydrofluoric acid generated by the reaction of the two is practically utilized for blocking objects. In other acid-based chemical well flushing methods, well flushing agents are injected into a borehole, wherein the well flushing agents comprise mineral water and other ions with low concentration or not contained in leachable agents, such as F -、Cl-、SiO2, on one hand, the washed well flushing water cannot directly enter a hydrometallurgy system, so that metal loss is caused, on the other hand, the residual other ions in the stratum reduce the resin adsorption efficiency, even poisoning is caused, and the like. The acidification is carried out before the acid process in-situ leaching new mining area is put into production, and the acidification mode is direct acidification or advanced acidification. The direct acidification is to inject the leaching agent into the injection well and extract the leaching solution from the extraction well, at the moment, the extraction and injection balance in the acidification period can be ensured, but the concentration of the leaching solution in the initial acidification stage can not reach the industrial requirement concentration, the advanced acidification is to inject the leaching agent into the formulated extraction well, the injection well does not work, and when the leaching agent fills half of the ore well gap, the leaching agent is injected from the injection well and extract the leaching solution from the extraction well, and the uranium concentration of the leaching solution can reach the industrial requirement concentration. In the technology, the air and piston well washing cleaning range is mainly used for drilling and mining layers near the drilling, for deep mining layers with the depth exceeding 600 meters, the load of an air compress