Method and system for inhibiting calcium carbonate precipitation in neutral in-situ leaching mine leaching process

Abstract

The invention belongs to inhibition methods and systems, and particularly relates to a method and a system for inhibiting calcium carbonate precipitation in a neutral in-situ leaching mine leaching process. The system for inhibiting calcium carbonate precipitation in the neutral in-situ leaching mine leaching process comprises a preparation tank, and the preparation tank is arranged beside a main pipeline and communicated with the leaching main pipeline through a pipeline. The method has the remarkable effects that the experiment of adding the inhibitor into the liquid injection hole is carried out in a certain uranium deposit in Xinjiang, the total number of the drilled holes is five, high-pressure intermittent well washing work is carried out before each test drilled hole is carried out, the average water quantity of the drilled holes after well washing is 3.4 m < 3 > / h, and the average flow rate increase is 34%. After the inhibitor is added, the average hold time of the drilling flow is prolonged to 67 days from 52 days, and the average increase rate is 28.8%.

Description

Technical Field

[0001] The present invention belongs to a suppression method and system, and particularly relates to a method and system for suppressing calcium carbonate precipitation in a neutral in-situ leaching mine leaching process. Background Art

[0002] Research has been conducted on various blockages generated after the operation of the mining area and solutions have been proposed. The main methods include air compressor well washing, high-pressure gas piston well washing, high-pressure gas piston chemical combined well washing, micro-acid air compressor well washing, dilute hydrochloric acid plug removal process, etc. The above well washing methods can remove different blockages and temporarily solve the problem of the decrease in the pumping and injection liquid volume caused by the blockage problem. In recent years, due to the high well washing intensity, the increase in well washing cost and the long-term complicated work, the well washing work has become the most important factor restricting the production operation of in-situ leaching mines. Summary of the Invention

[0003] In view of the defects of the prior art, the present invention provides a method for suppressing calcium carbonate precipitation in a neutral in-situ leaching mine leaching process.

[0004] The present invention is implemented as follows: A system for suppressing calcium carbonate precipitation in a neutral in-situ leaching mine leaching process, wherein, it includes a preparation tank, the preparation tank is arranged beside the main pipeline, and the preparation tank is connected to the main pipeline of the leaching through a pipeline.

[0005] For a system for suppressing calcium carbonate precipitation in a neutral in-situ leaching mine leaching process as described above, an electromagnetic metering pump is arranged on the preparation tank.

[0006] For a system for suppressing calcium carbonate precipitation in a neutral in-situ leaching mine leaching process as described above, a control valve is arranged on the pipeline connecting the preparation tank and the main pipeline.

[0007] A method for suppressing calcium carbonate precipitation in a neutral in-situ leaching mine leaching process, wherein, it includes the following steps:

[0008] Step 1: Selection of inhibitor

[0009] Select anhydrous sodium pyrophosphate as the inhibitor;

[0010] Step 2: Preparation of inhibitor

[0011] Dissolve solid anhydrous sodium pyrophosphate with clean water,

[0012] Step 3: Addition of inhibitor

[0013] Add the inhibitor prepared in Step 2 to the leaching solution;

[0014] Step 4: pH value adjustment

[0015] Adjust the pH value of the leaching solution by adding an acid-base solution to the leaching solution with the inhibitor added.

[0016] A method for inhibiting calcium carbonate precipitation in a neutral in-situ leaching process of a mine, wherein, in the second step, the concentration range of the dissolved sodium pyrophosphate anhydrous solution is 1-5 mg / L.

[0017] A method for inhibiting calcium carbonate precipitation in a neutral in-situ leaching process of a mine, wherein the preferred value of the concentration of the sodium pyrophosphate anhydrous solution in the second step is 3 mg / L.

[0018] A method for inhibiting calcium carbonate precipitation in a neutral in-situ leaching process of a mine, wherein, in the third step, the dosing rate range is 0.35-1.75 L / h.

[0019] A method for inhibiting calcium carbonate precipitation in a neutral in-situ leaching process of a mine, wherein, in the fourth step, the pH value of the leaching solution is in the range of 6.4-6.6.

[0020] The remarkable effect of the present invention is that an experiment on adding an inhibitor to the injection holes was carried out in a certain uranium deposit. A total of 5 boreholes were drilled. Before each test borehole was carried out, high-pressure intermittent well washing work was carried out. After well washing, the average water volume of the borehole was 3.4 m 3 / h, and the average flow rate increase was 34%. After adding the inhibitor, the average maintenance time of the borehole flow rate was increased from 52 d to 67 d, and the average increase rate was 28.8%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of on-site preparation of sodium pyrophosphate anhydrous

[0022] In the figure: 1. Preparation tank, 2. Electromagnetic metering pump, 3. Control valve, 4. PE injection pipe, 5. Injection hole DETAILED DESCRIPTION OF THE INVENTION

[0023] A method for inhibiting calcium carbonate precipitation in a neutral in-situ leaching process of a mine, comprising the following steps:

[0024] Step 1: Selection of inhibitor

[0025] In order to inhibit the formation of calcium carbonate, an inhibition test for inhibiting the formation of calcium carbonate was carried out in the laboratory. Finally, sodium pyrophosphate anhydrous was selected as the inhibitor. When the dosage is 1-5 mg / L, its inhibitory effect on calcium carbonate is strong and it has no influence on the leaching and adsorption of uranium.

[0026] Step 2: Calculation of dosing parameters

[0027] Step 2.1: Calculation of dosing amount

[0028] Dosing formula: (sodium pyrophosphate anhydrous / volume of preparation tank) / instantaneous injection volume = 1-5 mg / L.

[0029] Current injection volume: 3 - 5 m 3 / h;

[0030] Configuration concentration: 1 - 5 mg / L;

[0031] Current pH value of the leaching agent: 6.5 - 6.6.

[0032] Through calculation, to increase the concentration of sodium pyrophosphate anhydrous in the leaching agent to 3 mg / L, 1.8 - 9.0 kg of sodium pyrophosphate anhydrous needs to be dissolved in a 25 - L configuration tank, and added into a single injection hole at a rate of 0.35 - 1.75 L per hour using an electromagnetic metering pump.

[0033] Step 2.2: pH control measures

[0034] Control the pH value of the leaching agent at around 6.4 - 6.6 to avoid the generation of ore layer precipitation.

[0035] Step Three: Addition method

[0036] Place the configuration tank beside the target drilling hole in the centralized control room. The volume of the configuration tank is 25 L. There is an electromagnetic metering pump on the configuration tank. Put 1.8 - 9.0 kg of sodium pyrophosphate anhydrous into the configuration tank and dissolve it with clean water. The dissolved sodium pyrophosphate solution is added into a single injection hole at a rate of 0.35 - 1.75 L per hour.

[0037] Step Four: Prerequisites for addition work

[0038] The prerequisites include the following three points: (1) Lift the test hole to 3 - 5 m 3 / h through hole flushing. (2) Take the configuration clear water, tail liquid, and leaching liquid from the pumping holes around the target hole for chemical analysis, focusing on analyzing phosphorus, sodium, calcium, magnesium, uranium, and iron, and save this data as the base sample. (3) Install a transportation pipeline on the target hole.

[0039] As Figure 1 shown, place the configuration tank beside the target injection hole in the centralized control room. There is an electromagnetic metering pump on the configuration tank. Put 1.8 - 9.0 kg of sodium pyrophosphate anhydrous into the configuration tank and dissolve it with clean water. Open the control valve between the configuration transportation pipe and the PE injection pipe, set the electromagnetic metering pump to add 0.35 - 1.75 L per hour into a single injection hole, and adjust the injection pH value to 6.4 - 6.6 during the addition process to avoid the generation of calcium carbonate precipitation in the ore layer.

[0040] A specific example is given below.

[0041] An experiment on adding inhibitors to injection holes to inhibit calcium carbonate was carried out in a certain uranium deposit. A total of 5 boreholes were drilled. Before each test borehole was started, high-pressure intermittent well washing work was carried out. After well washing, the average water volume of the boreholes was 3.4 m 3 / h, and the average flow rate increase was 34%. After adding the inhibitor, the average maintenance time of the borehole flow rate increased from 52 d to 67 d, and the average increase rate of the maintenance time was 28.8%. By collecting the Ca 2+ concentration of the pumping holes near the test boreholes, it was found that compared with before adding, the Ca 2+ concentration started to rise slowly after 13 d, and the average increase was more than 23%; the Ca 2+ concentration started to decline slowly after 36 d and dropped to the concentration before adding after 9 d. During this period, the injection volume showed a slow downward trend and recovered to the flow rate before well washing after 67 d. This shows that after adding the inhibitor, it can indeed slow down the decline of the injection volume.

Claims

1. A system for inhibiting calcium carbonate precipitation in the leaching process of a neutral in-situ leaching mine, characterized in that: It includes a preparation tank (1), the preparation tank (1) is arranged beside the main pipeline, and the preparation tank (1) is communicated with the main pipeline of leaching through a pipeline.

2. The system for inhibiting calcium carbonate precipitation in the leaching process of a neutral in-situ leaching mine according to claim 1, characterized in that: An electromagnetic metering pump (2) is arranged on the preparation tank (1).

3. The system for inhibiting calcium carbonate precipitation in the leaching process of a neutral in-situ leaching mine according to claim 2, characterized in that: A control valve is arranged on the pipeline where the preparation tank (1) is communicated with the main pipeline.

4. A method for inhibiting calcium carbonate precipitation in the leaching process of a neutral in-situ leaching mine, characterized in that, It includes the following steps: Step 1: Inhibitor selection Select anhydrous sodium pyrophosphate as the inhibitor; Step 2: Prepare the inhibitor Dissolve solid anhydrous sodium pyrophosphate with clear water, Step 3: Add the inhibitor Add the inhibitor prepared in Step 2 to the leaching solution; Step 4: pH value adjustment Adjust the pH value of the leaching solution by adding acid-base solution to the leaching solution added with the inhibitor.

5. The method for inhibiting calcium carbonate precipitation in the leaching process of a neutral in-situ leaching mine according to claim 4, characterized in that: In Step 2, the concentration range of the dissolved anhydrous sodium pyrophosphate solution is 1 - 5 mg / L.

6. The method for inhibiting calcium carbonate precipitation in the leaching process of a neutral in-situ leaching mine according to claim 5, characterized in that: The preferred value of the concentration of the anhydrous sodium pyrophosphate solution in Step 2 is 3 mg / L.

7. The method for inhibiting calcium carbonate precipitation in the leaching process of a neutral in-situ leaching mine according to claim 6, characterized in that: In Step 3, the addition rate range is 0.35 - 1.75 L / h.

8. The method for inhibiting calcium carbonate precipitation in the leaching process of a neutral in-situ leaching mine according to claim 7, characterized in that: In Step 4, the pH value of the leaching solution is in the range of 6.4 - 6.6.

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