Leachate leached by uranium ore acid method and method

Abstract

The invention provides a leaching solution and method for uranium ore acid leaching, and particularly relates to the technical field of hydrometallurgy, and the leaching solution comprises an acid compound, an oxidizing agent, a fluorine salt compound and water. And leaching the uranium ore by adopting the leaching solution. During acid leaching, an oxidizing agent provides high oxidation potential to oxidize tetravalent uranium ores into hexavalent uranium ores, and hexavalent uranium ions and sulfate radicals are complexed and dissolved out; the fluorine ions react with S to release tetravalent uranium, the contact probability of the tetravalent uranium and the oxide is increased, the uranium leaching effect is enhanced, and the leaching rate is remarkably improved compared with an existing acid leaching method.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a leaching solution and a method for acid leaching of uranium ore. Background Art

[0002] The in-situ uranium leaching process is to inject a leaching agent prepared in a certain proportion into the ore layer through a borehole drilled from the surface to the ore-bearing layer. The injected leaching agent comes into contact with the useful components in the ore, undergoes a chemical reaction, and generates soluble compounds that leave the chemical reaction zone under the action of diffusion and convection and enter the solution flow that infiltrates and migrates along the ore layer.

[0003] The leaching of difficult-to-leach uranium ores is mainly achieved by changing the composition of the leaching agent, such as sulfuric acid in-situ leaching, carbonate in-situ leaching and neutral in-situ leaching, or adding various oxidants to convert tetravalent uranium into easily soluble hexavalent uranium. The second is to use external field enhancement methods to improve the uranium leaching rate, such as magnetic field magnetization to increase the activity of the leaching agent, micro-nano bubbles to increase dissolved CO2 and O2, and microwave assisted high-voltage pulse treatment of the leaching solution. The above-mentioned enhanced leaching methods have their own advantages and disadvantages, but they all have a common disadvantage, that is, the leaching rate of typical difficult-to-leach uranium ores is low. Summary of the invention

[0004] The object of the present invention is to provide a leachate and a method for acid leaching of uranium ore to improve the above problems. In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] The present application provides a leachate for acid leaching of uranium ore, the components of which include: an acid compound, an oxidant, a fluorine salt compound and water.

[0006] Optionally, the acid compound includes at least one of sulfuric acid, hydrochloric acid or nitric acid.

[0007] Optionally, the concentration of the acid compound in the leachate is 0.1-15 g / L.

[0008] Optionally, the oxidant includes at least one of hydrogen peroxide, potassium permanganate, sodium persulfate and sodium hypochlorite.

[0009] Optionally, the concentration of the oxidant in the leachate is 0.1-2.0 g / L.

[0010] Optionally, the fluorine salt compound includes at least one of sodium fluoride, ammonium fluoride, sodium borofluoride, ammonium borofluoride, manganese fluoride or magnesium fluoride.

[0011] Optionally, the concentration of the fluorine salt compound in the leachate is 0.1-10.0 g / L.

[0012] Based on the same inventive concept, the present application also provides a uranium ore acid leaching method, comprising:

[0013] The uranium ore is leached using the above leaching solution.

[0014] Optionally, the volume ratio of the uranium ore to the leaching solution is 1:(4.5-7).

[0015] Optionally, the uranium ore is leached for 12 hours to 72 hours.

[0016] The beneficial effects of the present invention are:

[0017] The present invention adopts an acid compound, an oxidant, and a fluorine salt compound to prepare a leaching agent. During acid leaching, the oxidant provides a high oxidation potential to oxidize the tetravalent uranium mineral into a hexavalent uranium mineral. The hexavalent uranium ions are complexed and dissolved with sulfate radicals, and the fluorine ions react with SiO2 to release tetravalent uranium, thereby increasing the contact probability between the tetravalent uranium and the oxide, strengthening the leaching effect, and effectively improving the leaching rate of uranium.

[0018] Other features and advantages of the present invention will be set forth in the following description, and in part will become apparent from the description, or may be understood by practicing embodiments of the present invention. DETAILED DESCRIPTION

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0020] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0021] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0022] Uranium resources exist in minerals in the form of tetravalent uranium and hexavalent uranium. The ratio of hexavalent uranium to tetravalent uranium in ordinary sandstone uranium ore is about 1:1. Generally, conventional acid leaching and CO2+O2 neutral leaching methods can easily achieve a higher uranium leaching rate.

[0023] However, the ratio of hexavalent uranium to tetravalent uranium in difficult-to-leach uranium ore is about 1:8. The ability of tetravalent uranium to be dissolved by acid is poor, and ordinary acid leaching only leaches hexavalent uranium with good solubility. It is usually necessary to further add an oxidant to the acid solution to oxidize the tetravalent uranium into hexavalent uranium for leaching.

[0024] The existing technology proposes to use external field enhancement methods to improve the uranium leaching rate, such as magnetic field magnetization leaching agent to improve the activity of leaching agent, micro-nano bubbles to improve dissolved CO2 and O2, using microwaves and high-voltage pulses to treat the leaching solution in the air with dielectric barrier discharge to improve the uranium leaching rate, gas-liquid phase pulse spark discharge device to atomize the leaching agent, etc., but these methods are still low for typical difficult-to-leach uranium ores. Especially for in-situ leaching of sandstone uranium ores, it can only be carried out at room temperature, and mining, crushing, and heating leaching cannot be carried out; and some sandstone uranium ores have a very low grade, with a uranium content of less than 0.05%, which makes the leaching of sandstone uranium ores more difficult and has a low leaching rate.

[0025] In order to solve the problems in the prior art, the present application provides a leaching solution for acid leaching of uranium ore, the components of which include: an acid compound, an oxidant, a fluorine salt compound and water.

[0026] The uranium leaching mechanism of the leaching solution of this application is mainly:

[0027] During acid leaching, the oxidant provides a high oxidation potential to oxidize the tetravalent uranium mineral into hexavalent uranium. The hexavalent uranium ions are complexed with sulfate and dissolved. The chemical mechanism is shown in chemical reaction formulas (1) and (2).

[0028] UO2+oxidant+2H + →H2O+UO2 2+ (1)

[0029] UO2 2+ +2SO4 2- →UO2(SO4)2 2- (2)

[0030] Fluoride ions react with SiO2 to release tetravalent uranium, increasing the contact probability between tetravalent uranium and oxides and enhancing the leaching of uranium. The chemical mechanism is shown in chemical reaction equations (3), (1) and (2).

[0031] 4H + +UO2.S iO2+4F - =UO2(s)+2H2O+SiF4(g) (3)

[0032] As an optional embodiment, the acid compound includes at least one of sulfuric acid, hydrochloric acid or nitric acid.

[0033] As an optional embodiment, the concentration of the acid compound in the leachate is 0.1-15 g / L.

[0034] Optionally, the oxidant includes at least one of hydrogen peroxide, potassium permanganate, sodium persulfate and sodium hypochlorite.

[0035] As an optional implementation manner, the concentration of the oxidant in the leachate is 0.1-2.0 g / L.

[0036] As an optional embodiment, the fluorine salt compound includes at least one of sodium fluoride, ammonium fluoride, sodium borofluoride, ammonium borofluoride, manganese fluoride or magnesium fluoride.

[0037] Since uranium ore contains a large amount of calcium carbonate, calcium fluoride precipitate will be preferentially generated when using a highly acidic fluorine salt compound, and a large amount of fluorine ions are consumed, which loses the function of reacting with SiO2 to release tetravalent uranium. At the same time, calcium fluoride precipitate is easily wrapped on the surface of uranium minerals, hindering the effective contact of the leaching solution with it, thereby reducing the uranium leaching rate; therefore, the fluorine salt compound in this application is preferably a non-acidic compound.

[0038] As an optional implementation manner, the concentration of the fluorine salt compound in the leaching solution is 0.1-10.0 g / L, and the higher the concentration, the better the leaching effect.

[0039] Based on the same inventive concept, the present application also provides a uranium ore acid leaching method, comprising:

[0040] The uranium ore is leached using the above leaching solution. The leaching solution is simply injected into the ore layer without heating. This method has excellent leaching effect on low-grade (<0.05%) difficult-to-leach uranium ore.

[0041] As an optional implementation manner, the volume ratio of the uranium ore to the leaching solution is 1:(4.5-7).

[0042] As an optional implementation manner, the uranium ore is leached for 12 hours to 72 hours.

[0043] The above-mentioned volume ratio of uranium ore to leaching solution and leaching time can be used as a reference for the amount of leaching solution and leaching time at the in-situ leaching site; it can also be used as a reference for the leaching process after mining.

[0044] The following embodiments of the present invention are described by specific examples. The following examples and comparative examples are all based on the Telaobao sandstone uranium ore as a sample. A certain amount of the sample is taken to carry out a leaching test in the laboratory. The grade of the sample uranium ore is 0.0276%. The analysis results of the main components of the ore are shown in Table 1. The water used to prepare the leaching solution in the leaching test is the ore layer water, and its main composition is shown in Table 2. The ore particle size composition distribution is shown in Table 3.

[0045] Table 1 Main components of the original ore of Telaobao sandstone uranium mine test

[0046]

[0047] Table 2 Main components of the ore layer water used in the test of Telaobao sandstone uranium mine

[0048]

[0049]

[0050] Table 3 Grain size distribution results of Telaobao sandstone uranium ore

[0051] Particle size range (mm) Weight(g) Mass distribution (%) Uranium grade (μg / g) Uranium distribution (%) >0.9 52.81 5.25 296 5.03 0.9-0.5 234.7 23.33 236 17.81 0.5-0.3 294.71 29.30 242 22.93 0.3-0.125 280.12 27.85 289 26.03 0.125-0.076 42 4.18 310 4.19 <0.076 101.5 10.09 736 24.02

[0052] Example 1

[0053] A method for acid leaching of uranium ore, comprising:

[0054] Prepare the leaching agent according to the concentration of sulfuric acid of 10g / L, hydrogen peroxide of 0.1g / L, and sodium fluoride of 10.0g / L;

[0055] The uranium ore was leached according to the volume ratio of leaching agent to uranium ore of 5:1. After leaching for 24 hours, the leaching results are shown in Table 4; the U content of the leaching solution is 42.0 mg / L, the slag grade is U0.006%, and the liquid leaching rate is 83.4%.

[0056] Table 4 Experimental results of Example 1

[0057]

[0058] Example 2

[0059] A method for acid leaching of uranium ore, comprising:

[0060] Prepare the leaching agent according to the concentration of hydrochloric acid 15g / L, potassium permanganate oxidant concentration 1.0g / L, and manganese fluoride concentration 1.0g / L;

[0061] The uranium ore was leached at a volume ratio of 6:1 between the leaching agent and the uranium ore. After leaching for 30 hours, the leaching results are shown in Table 5; the U content of the leaching solution was 42.2 mg / L, the slag grade was U0.00474%, and the liquid leaching rate was 76.3%.

[0062] Table 5 Experimental results of Example 2

[0063]

[0064]

[0065] Example 3

[0066] A method for acid leaching of uranium ore, comprising:

[0067] Prepare the leaching agent according to the concentration of nitric acid 3g / L, sodium hypochlorite oxidant 0.5g / L, and sodium borofluoride concentration 0.5g / L;

[0068] The uranium ore was leached according to the volume ratio of leaching agent to uranium ore of 5:1. After leaching for 20 hours, the leaching results are shown in Table 6; the U content of the leaching solution is 33.3 mg / L, the slag grade is U0.00888%, and the liquid leaching rate is 60.1%.

[0069] Table 6 Experimental results of Example 3

[0070]

[0071] Example 4

[0072] A method for acid leaching of uranium ore, comprising:

[0073] Prepare the leaching agent according to the concentration of nitric acid 8g / L, sodium persulfate oxidant 2g / L, and ammonium fluoride concentration 10g / L;

[0074] The uranium ore was leached according to the volume ratio of leaching agent to uranium ore of 4.5:1. After leaching for 72 hours, the leaching results are shown in Table 7; the U content of the leaching solution is 37.1 mg / L, the slag grade is U0.00563%, and the liquid leaching rate is 60.1%.

[0075] Table 7 Experimental results of Example 4

[0076]

[0077] Example 5

[0078] A method for acid leaching of uranium ore, comprising:

[0079] Prepare the leaching agent according to the concentration of sulfuric acid 12g / L, hydrogen peroxide oxidizing agent 1.5g / L, and magnesium fluoride concentration 5g / L;

[0080] The uranium ore was leached according to the volume ratio of leaching agent to uranium ore of 5.5:1. After leaching for 35 hours, the leaching results are shown in Table 8; the U content of the leaching solution is 44.6 mg / L, the slag grade is U0.00492%, and the liquid leaching rate is 60.1%.

[0081] Table 8 Experimental results of Example 5

[0082]

[0083] Comparative Example 1

[0084] Prepare the leaching agent according to the concentration of sulfuric acid 10g / L and hydrogen peroxide oxidizing agent 0.1g / L;

[0085] The uranium ore was leached according to the volume ratio of leaching agent to uranium ore of 5:1. After leaching for 24 hours, the leaching results are shown in Table 9; the U content of the leaching solution is 9.44 mg / L, the slag grade is U0.0224%, and the liquid leaching rate is 17.1%.

[0086] Table 9 Comparative Example 1 Test Results

[0087]

[0088] Comparative Example 2

[0089] Prepare the leaching agent according to the concentration of hydrochloric acid 15g / L and potassium permanganate oxidant 1.0g / L;

[0090] The uranium ore was leached according to the volume ratio of leaching agent to uranium ore of 6:1. After leaching for 30 hours, the leaching results are shown in Table 10; the leaching solution contained U37.9 mg / L, the slag grade was U0.0119%, and the liquid leaching rate was 68.6%.

[0091] Table 10 Comparative Example 2 Test Results

[0092]

[0093] Comparative Example 3

[0094] Prepare the leaching agent according to the concentration of 3g / L nitric acid and 0.5g / L sodium hypochlorite oxidant;

[0095] According to the volume ratio of leaching agent to uranium ore of 5:1, after leaching for 20 hours, the leaching results are shown in Table 11; the U content of the leachate is 24.9 mg / L, the slag grade is U0.0165%, and the liquid leaching rate is 40.22%.

[0096] Table 11 Comparative Example 3 Test Results

[0097]

[0098] It can be seen from the test results of Example 1 and Comparative Example 1 that after adding a large amount of sodium fluoride in Example 1, the uranium leaching rate is increased by 387% compared with that without adding sodium fluoride.

[0099] It can be seen from the test results of Example 2 and Comparative Example 2 that after adding sodium fluoride in Example 2, the uranium leaching rate is increased by 11.2% compared with the case without adding manganese fluoride.

[0100] It can be seen from the test results of Example 3 and Comparative Example 3 that after adding sodium fluoride in Example 3, the uranium leaching rate is increased by 49.4% compared with the case without adding sodium borofluoride.

[0101] It can be seen that the present application uses fluorine salt compounds and oxidants to jointly leach uranium ore, which can greatly improve the uranium leaching rate, and the more fluorine salt compounds are added, the better the effect of improving the leaching rate.

[0102] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A leachate from uranium ore acid leaching, characterized in that: The components of the leaching solution include: an acid compound, an oxidant, a fluorine salt compound and water.

2. The leachate of uranium ore acid leaching according to claim 1, characterized in that: The acid compound includes at least one of sulfuric acid, hydrochloric acid or nitric acid.

3. The leachate of uranium ore acid leaching according to claim 1, characterized in that: The concentration of the acid compound in the leachate is 0.1-15 g / L.

4. The leachate of uranium ore acid leaching according to claim 1, characterized in that: The oxidant includes at least one of hydrogen peroxide, potassium permanganate, sodium persulfate and sodium hypochlorite.

5. The leachate of uranium ore acid leaching according to claim 1, characterized in that: The concentration of the oxidant in the leachate is 0.1-2.0 g / L.

6. The leachate of uranium ore acid leaching according to claim 1, characterized in that: The fluorine salt compound includes at least one of sodium fluoride, ammonium fluoride, sodium borofluoride, ammonium borofluoride, manganese fluoride or magnesium fluoride.

7. The leachate of uranium ore acid leaching according to claim 1, characterized in that: The concentration of the fluorine salt compound in the leachate is 0.1-10.0 g / L.

8. A method for acid leaching of uranium ore, characterized in that: include: The uranium ore is leached using the leaching solution as described in any one of claims 1 to 7.

9. A method for acid leaching of uranium ore according to claim 8, characterized in that: The volume ratio of the uranium ore to the leaching solution is 1:(4.5-7).

10. The method for acid leaching of deuranium ore according to claim 1, characterized in that: The uranium ore is leached for 12 hours to 72 hours.

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