Leaching method of uranium ore with high acid consumption

Abstract

The invention relates to the technical field of production for extracting uranium from uranium ore, and discloses a leaching method for uranium ore with high acid consumption. The high-acid-consumption uranium ore leaching method comprises the following steps: preparing leaching ore pulp; and adding high-valence iron salt into the leached ore pulp and stirring. And an oxidizing agent is added into the leached ore pulp, and oxidized leached ore pulp is obtained. And concentrated sulfuric acid is added into the oxidation leaching ore pulp, stirring is conducted for 1 min to 2 min, and first-stage uranium leaching is conducted. Carrying out thickening treatment on ore pulp obtained by leaching uranium in the first section to obtain thick supernate and thick ore pulp; and a sulfuric acid solution is added into the dense ore pulp, stirring is conducted for 3 min to 30 min, and second-stage uranium leaching is conducted. And carrying out solid-liquid separation treatment on ore pulp obtained by the second-stage uranium leaching to obtain separated clear liquid and leaching residues. According to the method, the acid consumption and the production cost are reduced and the uranium leaching rate is improved by adding the high-valence ferric salt and the oxidizing agent as leaching aids and adopting a segmented acid adding mode of short-time contact of the concentrated sulfuric acid and long-time contact of the sulfuric acid solution.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of uranium extraction from uranium ore, and particularly relates to a leaching method for high-acid-consumption uranium ore. BACKGROUND

[0002] The uranium ore leaching process mainly includes in-situ leaching, heap leaching and agitation leaching. Since the mineral composition of the uranium ore contains carbonate minerals, the acid consumption is increased when the uranium is leached by using the acid leaching process. In particular, for some ores with low uranium grade and high carbonate mineral content, the high acid consumption leads to high production cost, which is economically unfeasible.

[0003] The sandy mudstone uranium ore is rich in carbonate minerals and gypsum minerals, and the reagent consumption is high no matter whether the acid leaching or the alkali leaching is adopted. In particular, when the acid leaching is adopted, the acid consumption is as high as 25%, leading to high production cost. SUMMARY

[0004] The application aims to at least solve one of the technical problems in the related art.

[0005] Therefore, the application provides a leaching method for high-acid-consumption uranium ore, which comprises the following steps: preparing a leaching ore slurry; adding a high-valence iron salt to the leaching ore slurry and stirring; adding an oxidizing agent to the leaching ore slurry to which the high-valence iron salt has been added, to obtain an oxidized leaching ore slurry; adding concentrated sulfuric acid to the oxidized leaching ore slurry and stirring for 1 min to 2 min, to perform first-stage uranium leaching; performing thickening treatment on the ore slurry obtained by the first-stage uranium leaching, to obtain thickening supernatant and thickening ore slurry; adding a sulfuric acid solution to the thickening ore slurry and stirring for 3 min to 30 min, to perform second-stage uranium leaching; and performing solid-liquid separation treatment on the ore slurry obtained by the second-stage uranium leaching, to obtain a separation supernatant and a leaching residue.

[0006] In one possible implementation, in the step of adding the high-valence iron salt to the leaching ore slurry and stirring, the mass of the high-valence iron salt is 0.1% to 2.0% of the mass of the ore in the leaching ore slurry; and the stirring is performed at a stirring speed of 100 r / min to 500 r / min for 1 min to 20 min.

[0007] In one possible implementation, the high-valence iron salt comprises iron sulfate or iron chloride; and the oxidizing agent comprises MnO2.

[0008] In a possible implementation, the step of adding an oxidizing agent to the leaching ore slurry to which the high-valence iron salt has been added to obtain an oxidized leaching ore slurry comprises: adding the oxidizing agent to the leaching ore slurry to which the high-valence iron salt has been added, the mass of the oxidizing agent being 0.2% to 3% of the mass of the ore in the leaching ore slurry; and stirring for 1 minute to 20 minutes at a stirring speed of 100 r / min to 500 r / min to obtain the oxidized leaching ore slurry.

[0009] In a possible implementation, in the step of adding concentrated sulfuric acid to the oxidized leaching ore slurry, the mass concentration of the concentrated sulfuric acid is 98%, the concentrated sulfuric acid is added in a continuous dropwise manner, and the mass of the added sulfuric acid is 3% to 15% of the mass of the ore in the leaching ore slurry.

[0010] In a possible implementation, the step of adding a sulfuric acid solution to the thickened ore slurry and stirring for 3 minutes to 30 minutes to perform two-stage leaching of uranium comprises: adding the sulfuric acid solution to the thickened ore slurry, the mass concentration of the sulfuric acid solution being 2% to 10%, the mass of the added sulfuric acid being 2% to 8% of the mass of the ore in the leaching ore slurry, and stirring for 3 minutes to 30 minutes at a stirring speed of 50 r / min to 500 r / min to perform two-stage leaching of uranium.

[0011] In a possible implementation, the method further comprises: determining the mass of the sulfuric acid in the thickened supernatant; and adding a sulfuric acid solution to the thickened supernatant, so that the mass of the sulfuric acid in the thickened supernatant is 2% to 8% of the mass of the ore in the leaching ore slurry.

[0012] In a possible implementation, the step of preparing the leaching ore slurry comprises: mixing the ore with water in a mass ratio of 1:1 to 1:5 and stirring to obtain an ore slurry; screening and grading the ore slurry to obtain coarse-grained ore and fine-grained ore; grinding the coarse-grained ore to obtain a ground ore slurry; and mixing the fine-grained ore with the ground ore slurry to obtain the leaching ore slurry.

[0013] In a possible implementation, the step of screening and grading the ore slurry to obtain coarse-grained ore and fine-grained ore comprises: screening and grading the ore slurry by using a sieve with a mesh size of 0.05 mm to 0.25 mm to obtain the coarse-grained ore and the fine-grained ore.

[0014] In a possible implementation, in the step of grinding the coarse-grained ore, the coarse-grained ore is ground to a particle size of less than 0.25 mm.

[0015] The method for leaching high-acid-consumption uranium ore provided in the application can at least achieve the following technical effects:

[0016] In the present application, the leaching slurry is prepared to provide a basic slurry for the subsequent full contact between the ore and the chemical reagent. The high-valence iron salt is added to the leaching slurry and stirred to provide an ionic environment for the leaching of uranium. The oxidizing agent (MnO2) is further added to the leaching slurry to create a high-potential oxidizing environment, which efficiently oxidizes the low-valence uranium (tetravalent uranium) that is difficult to leach into the high-valence uranium (hexavalent uranium) that is easy to leach, converts the uranium from the insoluble state into the soluble state, and further improves the leaching rate of uranium to reduce the acid consumption in the subsequent first-stage leaching of uranium. The concentrated sulfuric acid is added to the oxidized leaching slurry and stirred for 1 min to 2 min, i.e., the concentrated sulfuric acid is in short-time contact with the ore, which can not only make the uranium in the adsorbed state of the ore leach quickly, but also reduce the acid consumption and achieve the retention of as much residual acid as possible for the recycling of the acid in the subsequent processing to further reduce the acid consumption. The sulfuric acid solution is added to the thickened slurry and stirred for 3 min to 30 min, i.e., the sulfuric acid is in long-time contact with the ore to make the uranium leach fully to improve the uranium leaching rate.

[0017] The foregoing general description and the following description are only exemplary and explanatory, and are not used to limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0018] One or more embodiments are illustrated by way of example in the drawings and are not intended to be limiting of the embodiments. Identical reference numbers in the figures indicate the same elements. The drawings are not to scale and are intended for use only in conjunction with the description below, wherein:

[0019] Figure 1 The flow chart of the leaching method provided for one embodiment of the present disclosure;

[0020] Figure 2 The process flow chart of the leaching method provided for another embodiment of the present disclosure. DETAILED DESCRIPTION

[0021] In order to enable a more detailed understanding of the features and technical content of the embodiments of the present disclosure, the implementation of the embodiments of the present disclosure is described in detail below in conjunction with the drawings, which are only used for reference and do not limit the embodiments of the present disclosure. In the following technical description, a plurality of details are provided for the purpose of facilitating explanation, so as to provide a full understanding of the disclosed embodiments. However, one or more embodiments can still be implemented without these details. In other cases, well-known structures and devices can be simplified for the purpose of simplifying the drawings.

[0022] It should be noted that the embodiments in the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0023] It should be noted that in the embodiment described in the present application, the mass of sulfuric acid can refer to the mass of sulfuric acid solute, which will not be described below.

[0024] In combination Figure 1 As shown in the present application, a leaching method of high-acid-consuming uranium ore is provided, comprising the following steps:

[0025] S11, preparing a leaching ore slurry.

[0026] In the present embodiment, by preparing a leaching ore slurry, a basic ore slurry is provided for subsequent sufficient contact between the ore and chemical reagents.

[0027] In some embodiments, the step of preparing a leaching ore slurry comprises: mixing and stirring the ore and water in a mass ratio of 1:1 to 1:5 to obtain an ore slurry. The ore slurry is classified by screening to obtain coarse-grained ore and fine-grained ore. The coarse-grained ore is ground to obtain a ground ore slurry. The fine-grained ore and the ground ore slurry are mixed to obtain a leaching ore slurry.

[0028] In the present embodiment, by classifying the ore slurry, the ore slurry is divided into fine-grained ore that has reached the target particle size and coarse-grained ore that needs further processing, improving the efficiency of subsequent grinding. By grinding, the specific surface area of the reaction is increased, so that the target uranium minerals are fully exposed and effectively contacted with oxidizing agents, sulfuric acid, etc., thereby improving the leaching rate. By mixing the fine-grained ore and the ground ore slurry, the particle size distribution of the leaching ore slurry is uniform, the mineral composition is stable, and the consistency of the entire leaching system is achieved.

[0029] By adjusting the solid-liquid ratio of the leaching ore slurry, such as adjusting the solid-liquid ratio of the leaching ore slurry to 1:1 to 1:3, the viscosity, diffusion rate and mass transfer efficiency of the reaction system are controlled, which is conducive to the uniform distribution of acid and the efficient leaching of uranium.

[0030] In some embodiments, the step of classifying the ore slurry to obtain coarse-grained ore and fine-grained ore comprises: using a sieve with a mesh size of 0.05mm to 0.25mm to classify the ore slurry to obtain coarse-grained ore and fine-grained ore.

[0031] In the present embodiment, the acid-consuming minerals (such as carbonates) and uranium-containing minerals in the ore may not be evenly distributed in different particle sizes. By using a specific sieve aperture of 0.05mm to 0.25mm, the fine-grained minerals that have been monomer dissociated (which may contain a large amount of fine-grained carbonate that is easy to consume acid and part of the dissociated uranium minerals) can be efficiently separated from the coarse-grained minerals that need to be re-ground, improving the efficiency of subsequent grinding.

[0032] In one possible implementation, the mesh size is 0.05mm, 0.10mm, 0.15mm, 0.25mm or other values between 0.05mm and 0.25mm.

[0033] In some embodiments, the step of grinding the coarse fraction of the ore is performed to a particle size of less than 0.25 mm.

[0034] In this embodiment, after the coarse fraction of the ore is ground to a particle size of less than 0.25 mm, the ground coarse fraction is mixed with the fine fraction to obtain a leaching slurry with a relatively concentrated and uniform particle size distribution. This uniformity means that the reaction rate is consistent: the particle surface area is similar, the acid and oxidizing agent react with the particles at a more synchronized rate, thereby making the reaction time more consistent and shortening the leaching period. Reducing acid consumption: uniform particles make the acid consumption per unit of ore more stable, facilitating accurate control of the amount of acid added in stages, achieving reduced acid consumption and improved uranium leaching rate.

[0035] A specific application example is provided to illustrate the process of preparing the leaching slurry. The ore is mixed with water in a ratio of 1:1 to 1:5 by mass, placed in a stirrer, and dispersed with a stirring paddle to obtain a slurry. A sieve with a mesh size of 0.05 mm to 0.25 mm is used to screen and classify the dispersed slurry to obtain a coarse fraction and a fine fraction. The coarse fraction is ground to a particle size of less than 0.25 mm. The fine fraction is mixed with the ground slurry to obtain a leaching slurry. The concentration of the leaching slurry is adjusted to a solid-liquid ratio of 1:1 to 1:3.

[0036] S12, adding a high-valent iron salt to the leaching slurry and stirring.

[0037] In this embodiment, by adding a high-valent iron salt to the leaching slurry, an ionic environment is provided for the leaching of uranium.

[0038] In one possible implementation, the stirring speed is 100 r / min, 200 r / min, 300 r / min, 400 r / min, 500 r / min, or other values between 100 r / min and 500 r / min.

[0039] In some embodiments, the high-valent iron salt includes iron sulfate or iron chloride, which can act together with the subsequent leaching agent, sulfuric acid, through oxidation-reduction reaction and complexation to improve the leaching efficiency and effect of uranium.

[0040] In some embodiments, in the step of adding a high-valent iron salt to the leaching slurry and stirring, the mass of the high-valent iron salt is 0.1% to 2.0% of the mass of the ore in the leaching slurry. The stirring speed is 100 r / min to 500 r / min, and the stirring time is 1 min to 20 min.

[0041] In the embodiment, the mass of the high-valence iron salt is 0.1% to 2.0% of the mass of the ore in the leaching slurry, so as to achieve a better balance between the oxidation effect and the control of the reagent cost. For example, if the addition amount is too small, it is insufficient to create a sufficient oxidation environment, which affects the leaching rate. If the addition amount is too large, it will cause waste of reagents, increase the cost, and possibly introduce too many impurity ions.

[0042] In the embodiment, the high-valence iron salt is added to the leaching slurry, the mass of the high-valence iron salt is 0.1% to 2.0% of the mass of the ore in the leaching slurry, and a stirrer is used for stirring at a stirring speed of 100 r / min to 500 r / min for 1 min to 20 min, so as to uniformly disperse the high-valence iron salt.

[0043] S13. An oxidizing agent is added to the leaching slurry to which the high-valence iron salt has been added, to obtain an oxidized leaching slurry.

[0044] By adding the oxidizing agent, a high-potential oxidizing environment is created and maintained. The low-valence uranium (tetravalent uranium) that is difficult to leach is efficiently oxidized to high-valence uranium (hexavalent uranium) that is easy to leach, the uranium is converted from a difficult-to-dissolve state to a soluble state, and the leaching rate of the uranium is improved to reduce the acid consumption in the subsequent first-stage leaching of the uranium, and the uranium leaching rate is also improved.

[0045] In some embodiments, the oxidizing agent includes MnO2.

[0046] By using iron sulfate as a co-leaching agent, redox and complexation effects are exerted in the leaching process. The low-valence uranium is oxidized to high-valence uranium that is easy to leach by MnO2, and the leaching rate of the uranium is improved. Through the synergistic effect of iron sulfate and MnO2, the leaching time of the uranium can be reduced, the leaching rate of the uranium can be improved, the acid consumption in the leaching process can be effectively reduced, and the cost can be reduced.

[0047] In some embodiments, the step of adding an oxidizing agent to the leaching slurry to which the high-valence iron salt has been added to obtain an oxidized leaching slurry includes: adding an oxidizing agent to the leaching slurry to which the high-valence iron salt has been added. The mass of the oxidizing agent is 0.2% to 3% of the mass of the ore in the leaching slurry. The leaching slurry is stirred at a stirring speed of 100 r / min to 500 r / min for 1 min to 20 min to obtain the oxidized leaching slurry.

[0048] Specifically, the oxidizing agent MnO2 is added to the leaching slurry to which the high-valence iron salt has been added, the mass of the oxidizing agent is 0.2% to 3% of the mass of the ore in the leaching slurry, and the leaching slurry is stirred at a stirring speed of 100 r / min to 500 r / min for 1 min to 20 min by using a stirrer. That is, by setting the amount of the oxidizing agent and the reaction conditions, efficient and economical oxidation and activation of the high-adsorption uranium ore is achieved, so as to reduce the acid consumption and improve the uranium leaching rate.

[0049] S14, concentrated sulfuric acid is added to the oxidized leaching ore slurry, and stirred for 1-2 minutes to leach uranium in the first stage.

[0050] In this embodiment, concentrated sulfuric acid is added to the oxidized leaching ore slurry to provide an acidic environment. Stirring for 1-2 minutes, that is, short-time contact of concentrated sulfuric acid with the ore, can not only quickly leach the uranium in the adsorbed state in the ore, but also reduce acid consumption, retain as much residual acid as possible for recycling in subsequent processing, and further reduce acid consumption.

[0051] That is, the present embodiment not only efficiently dissolves the activated uranium with acid, but also forcibly terminates the ineffective reaction of concentrated sulfuric acid with acid-consuming minerals, effectively reducing acid consumption and achieving low acid consumption and high efficiency.

[0052] Further, more than 90% of the uranium in sandy mudstone uranium ore exists in an adsorbed state. By taking advantage of the leaching time difference between acid-consuming substances and uranium in the ore, high-valent iron salt and oxidizing agent are used as leaching aids to adjust the form of uranium, and then concentrated sulfuric acid is added for short-time stirring to achieve fast leaching and further reduce acid consumption.

[0053] In some embodiments, in the step of adding concentrated sulfuric acid to the oxidized leaching ore slurry, the mass concentration of the concentrated sulfuric acid is 98%, the concentrated sulfuric acid is added in a continuous dropwise manner, and the mass of the sulfuric acid is 3%-15% of the mass of the ore in the leaching ore slurry.

[0054] By continuously adding concentrated sulfuric acid with a mass concentration of 98% to the oxidized leaching ore slurry, the mass of the sulfuric acid is 3%-15% of the mass of the ore in the leaching ore slurry, which can reduce the probability of violent reaction of concentrated sulfuric acid with acid-consuming minerals (such as carbonates), reduce ineffective acid consumption, and improve the utilization efficiency of acid. Also, while reducing acid consumption, effective leaching of uranium can be achieved. The present embodiment is suitable for uranium ore mainly in adsorbed state, and can improve the leaching rate and leaching rate of uranium.

[0055] S15, the ore slurry obtained by leaching uranium in the first stage is subjected to thickening treatment to obtain thickening supernatant and thickening ore slurry.

[0056] In this embodiment, the liquid phase (containing soluble uranium and residual acid) that has completed most of the reaction is separated from the solid phase containing unreacted uranium minerals and acid-consuming substances by thickening treatment, effectively locking the stage leaching results and recycling the residual acid.

[0057] S16, sulfuric acid solution is added to the thickening ore slurry, and stirred for 3-30 minutes to leach uranium in the second stage.

[0058] In the embodiment, the sulfuric acid solution is added to the thickened ore slurry under the premise of low acid consumption, and stirred for 3 minutes to 30 minutes, that is, by targeted acid supplementing and prolonging the reaction time, the uranium remaining in the first-stage leaching is deeply extracted, and the total recovery rate of uranium is improved.

[0059] In some embodiments, the step of adding the sulfuric acid solution to the thickened ore slurry and stirring for 3 minutes to 30 minutes to perform the second-stage uranium leaching includes: adding the sulfuric acid solution to the thickened ore slurry, the mass concentration of the sulfuric acid solution being 2% to 10%, the mass of the added sulfuric acid being 2% to 8% of the mass of the ore in the leaching ore slurry, and stirring for 3 minutes to 30 minutes under the condition that the stirring speed is 50 r / min to 500 r / min to perform the second-stage uranium leaching.

[0060] Specifically, the sulfuric acid solution with a mass concentration of 2% to 10% is added to the thickened ore slurry, the mass of the sulfuric acid being 2% to 8% of the mass of the ore in the leaching ore slurry, and the stirring is performed by the stirrer under the condition that the stirring speed is 50 r / min to 500 r / min for 3 minutes to 30 minutes.

[0061] In the embodiment, by adding the low-concentration sulfuric acid solution (with a mass concentration of 2% to 10%), the uranium minerals in the form of bitumen uranium ore and the like in the ore are further fully reacted with the acid.

[0062] S17, performing solid-liquid separation treatment on the ore slurry obtained by the second-stage uranium leaching to obtain separated clear liquid and leaching residue.

[0063] In the embodiment, by performing the solid-liquid separation treatment on the ore slurry obtained by the second-stage uranium leaching, the separation of the clear liquid and the solid waste (leaching residue) is completed, and the uranium recovery rate is improved.

[0064] In some embodiments, the leaching method further includes: determining the mass of the sulfuric acid in the thickened supernatant. The sulfuric acid solution is added to the thickened supernatant so that the mass of the sulfuric acid in the thickened supernatant is 2% to 8% of the mass of the ore in the leaching ore slurry.

[0065] Through accurate quantitative analysis and control, the leaching agent is provided for the subsequent uranium leaching process, the residual acid in the first-stage leaching liquid is recycled in the subsequent process, and the purpose of significantly reducing the total acid consumption is achieved.

[0066] For example, the mass of the sulfuric acid in the thickened supernatant is determined, the sulfuric acid solution is added to the thickened supernatant so that the mass of the sulfuric acid in the thickened supernatant is 2% to 8% of the mass of the ore in the leaching ore slurry, and the sulfuric acid solution is used as the leaching agent in the step of the second-stage uranium leaching.

[0067] In combination with Figure 2 As shown in the drawings, the present disclosure also provides a leaching method for high-acid-consumption uranium ore, including the following steps:

[0068] Prepare the raw ore. The raw ore includes uranium ore.

[0069] Stir and disperse. For example, mix the ore and water in a mass ratio of 1:1 to 1:5, put them into a stirrer, and disperse them with a stirring paddle to obtain an ore slurry.

[0070] Classify. For example, use a sieve with a mesh size of 0.15 mm to screen and classify the ore slurry to obtain fine-grained ore (i.e., -0.15 mm size fraction) that passes through the sieve and coarse-grained ore (i.e., +0.15 mm size fraction) that does not pass through the sieve.

[0071] Grind the ore. For example, grind the coarse-grained ore to a particle size of less than 0.15 mm (i.e., to achieve a -0.15 mm size fraction) to obtain a ground ore slurry.

[0072] Mix the fine-grained ore with the ground ore slurry to obtain a leaching ore slurry.

[0073] Add ferric sulfate. For example, add ferric sulfate to the leaching ore slurry and stir. The mass of the ferric sulfate is 1.5% of the mass of the ore in the leaching ore slurry. The stirring can be performed at a stirring speed of 100 r / min to 500 r / min for 1 min to 20 min.

[0074] Add manganese dioxide. For example, add manganese dioxide (MnO2) to the leaching ore slurry to which the ferric sulfate has been added to obtain an oxidized leaching ore slurry. The mass of the manganese dioxide is 0.8% of the mass of the ore in the leaching ore slurry.

[0075] Add concentrated sulfuric acid to perform first-stage uranium leaching. Specifically, add concentrated sulfuric acid to the oxidized leaching ore slurry and stir for 1 min to 2 min to perform first-stage uranium leaching. The mass concentration of the concentrated sulfuric acid is 98%, and the mass of the sulfuric acid is 11% of the mass of the ore in the leaching ore slurry.

[0076] Thickening treatment. Specifically, perform thickening treatment on the ore slurry obtained by first-stage uranium leaching to obtain thickening supernatant and thickening ore slurry.

[0077] Add a sulfuric acid solution to the thickening ore slurry to perform second-stage uranium leaching. Specifically, add a sulfuric acid solution to the thickening ore slurry and stir for 3 min to 30 min to perform second-stage uranium leaching. The mass concentration of the sulfuric acid solution is 2% to 10%, and the mass of the sulfuric acid is 7% of the mass of the ore in the leaching ore slurry.

[0078] Perform filtration to obtain separated supernatant and leaching residue. Specifically, perform solid-liquid separation treatment (which can be filtration) on the ore slurry obtained by second-stage uranium leaching to obtain separated supernatant and leaching residue.

[0079] For the thickened supernatant, a sulfuric acid solution is added to obtain a secondary leaching agent. For example, the mass of sulfuric acid in the thickened supernatant is determined. The sulfuric acid solution is added to the thickened supernatant so that the mass of sulfuric acid in the thickened supernatant is 2% to 8% of the mass of the ore in the leaching slurry, and is used as a leaching agent (sulfuric acid solution) in the secondary uranium leaching step, to further reduce acid consumption.

[0080] Next, by way of example, the leaching of a sandy mudstone type uranium ore is described in Examples 1 to 5 and Comparative Examples 1 and 2. In the uranium ore, more than 90% of the uranium is present in an adsorbed state, and a very small amount is present in the form of the independent mineral pitchblende. The acid-consuming substance content in the uranium ore is high, the CO2 content is 9.75%, and the uranium content is 0.083%.

[0081] Example 1

[0082] A method for leaching a high-acid-consuming uranium ore includes the following steps:

[0083] The ore and water are mixed in a mass ratio of 1:3, and are placed in a stirrer and dispersed with a stirring paddle to obtain a slurry.

[0084] The slurry is classified using a sieve with a mesh size of 0.20 mm to obtain +0.2 mm coarse-grained ore and -0.20 mm fine-grained ore.

[0085] The +0.20 mm coarse-grained ore is ground to a particle size of <0.20 mm to obtain a ground slurry.

[0086] The ground slurry and the fine-grained ore are combined to obtain a leaching slurry.

[0087] The concentration of the leaching slurry is adjusted to a solid-liquid ratio of 1:2.5.

[0088] Iron sulfate is added to the leaching slurry. The mass of the iron sulfate is 1% of the mass of the ore in the leaching slurry, and the stirring speed is 150 r / min for 5 min.

[0089] An oxidizing agent MnO2 is added to the leaching slurry to which the iron sulfate has been added to obtain an oxidized leaching slurry. The mass of the oxidizing agent is 0.5% of the mass of the ore in the leaching slurry, and the stirring speed is 150 r / min for 5 min.

[0090] A mass-concentration of 98% concentrated sulfuric acid is continuously added to the oxidized leaching slurry in a dropwise manner, the mass of the sulfuric acid is 12% of the mass of the ore in the leaching slurry, and the stirring speed is 150 r / min for 1 min to perform a first-stage uranium leaching.

[0091] The slurry obtained by the first-stage uranium leaching is thickened to obtain a thickened supernatant and a thickened slurry.

[0092] A 4% sulfuric acid solution was added to the thick slurry, with the mass of the sulfuric acid being 5% of the mass of the ore in the leaching slurry. The mixture was stirred for 10 minutes at a stirring speed of 150 r / min to carry out the second stage of uranium leaching.

[0093] The slurry obtained from the second stage of uranium leaching was subjected to solid-liquid separation treatment to obtain a clear separation liquid and leaching residue.

[0094] As shown in Table 1, in Example 1, the mass of sulfuric acid used was 17% of the ore mass in the leaching slurry, a relatively low amount. Specifically, in the first stage of uranium leaching, the mass of sulfuric acid was 12% of the ore mass in the leaching slurry, and in the second stage, it was 5%. It is evident that the uranium ore leaching method provided in Example 1 can reduce acid consumption. Furthermore, the uranium grade of the leaching residue obtained in Example 1 was 0.016%, and the uranium leaching rate was 80.72%, achieving a high uranium leaching rate while reducing acid consumption.

[0095] Comparative Example 1

[0096] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 omits the thickening treatment after the first stage of uranium leaching, the second stage of uranium leaching, and the solid-liquid separation process. During the first stage of uranium leaching, the mass of sulfuric acid is 20% of the ore mass in the leaching slurry, and the concentrated sulfuric acid is added to the oxidative leaching slurry all at once. After the first stage of uranium leaching, the resulting slurry is directly filtered to obtain a clear liquid and leaching residue.

[0097] The remaining steps of uranium leaching in Comparative Example 1, as well as the steps preceding uranium leaching, are the same as in Example 1.

[0098] As shown in Table 1, in Comparative Example 1, the mass of sulfuric acid used was 20% of the ore mass in the leaching slurry, which is a relatively high amount. The uranium grade of the leaching residue obtained in Comparative Example 1 was 0.025%, and the uranium leaching rate was 69.88%. It can be seen that Comparative Example 1 had high acid consumption and low uranium leaching rate.

[0099] Comparative Example 2

[0100] The difference between Comparative Example 2 and Example 1 is that ferric sulfate was not added to the leaching slurry.

[0101] The remaining steps of Comparative Example 2 are the same as those of Example 1.

[0102] As shown in Table 1, in Comparative Example 2, the mass of sulfuric acid used was 17% of the ore mass in the leaching slurry. Specifically, during the first stage of uranium leaching, the mass of sulfuric acid was 12% of the ore mass in the leaching slurry, and during the second stage, it was 5% of the ore mass. The uranium grade of the leaching residue obtained in Comparative Example 2 was 0.019%, and the uranium leaching rate was 77.11% (below 80%). It is evident that while Comparative Example 2 reduced acid consumption, it resulted in a low uranium leaching rate.

[0103] Example 2

[0104] A leaching method for high acid-consuming uranium ore includes the following steps:

[0105] The ore and water are mixed in a mass ratio of 1:3, and then placed in a mixer and stirred with a paddle to obtain a slurry.

[0106] The above slurry was graded using a sieve with a mesh size of 0.15 mm, separating it into coarse-grained ore of +0.15 mm and fine-grained ore of -0.15 mm.

[0107] The sieved +0.15mm coarse-grained ore is ground to a particle size <0.15mm to obtain a ground slurry.

[0108] The ground slurry is combined with the screened fine-grained ore to obtain the leaching slurry.

[0109] Adjust the concentration of the leaching slurry to a solid-liquid ratio of 1:2.

[0110] Ferric sulfate was added to the leaching slurry. The mass of ferric sulfate was 1.5% of the mass of the ore in the leaching slurry. The mixture was stirred for 8 minutes at a stirring speed of 200 r / min.

[0111] Oxidant MnO2 was added to the leaching slurry containing ferric sulfate to obtain an oxidized leaching slurry. The mass of the oxidant was 1.0% of the mass of the ore in the leaching slurry. The mixture was stirred for 8 minutes at a stirring speed of 200 r / min.

[0112] Concentrated sulfuric acid with a mass concentration of 98% was added to the oxidative leaching slurry using a continuous dripping method. The mass of sulfuric acid was 13% of the mass of the ore in the leaching slurry, and the mixture was stirred for 2 minutes to carry out a first stage of uranium leaching.

[0113] The slurry obtained from uranium leaching is thickened to obtain a thickened supernatant and a thickened slurry.

[0114] A 5% sulfuric acid solution was added to the thick slurry, with the mass of the sulfuric acid being 6% of the mass of the ore in the leaching slurry. The mixture was stirred for 8 minutes at a stirring speed of 200 r / min to carry out the second stage of uranium leaching.

[0115] The slurry obtained from the second stage of uranium leaching was subjected to solid-liquid separation treatment to obtain a clear separation liquid and leaching residue.

[0116] As shown in Table 1, in Example 2, the mass of sulfuric acid used was 19% of the ore mass in the leaching slurry, a relatively low amount. Specifically, in the first stage of uranium leaching, the mass of sulfuric acid was 13% of the ore mass in the leaching slurry, and in the second stage, it was 6%. It is evident that the uranium ore leaching method provided in Example 2 can reduce acid consumption. Furthermore, the uranium grade of the leaching residue obtained in Example 2 was 0.013%, and the uranium leaching rate was 84.34%, achieving a high uranium leaching rate while reducing acid consumption.

[0117] Table 1. Leaching conditions and results of uranium ore

[0118]

[0119] Example 3

[0120] The difference between Example 3 and Example 2 is that the mass of ferric sulfate is 2% of the mass of the ore in the leaching pulp. When concentrated sulfuric acid with a mass concentration of 98% is added to the oxidative leaching pulp, the mass of the sulfuric acid is 12% of the mass of the ore in the leaching pulp.

[0121] The remaining steps of Example 3 are the same as those of Example 2.

[0122] As shown in Table 1, in Example 3, the mass of sulfuric acid used was 18% of the ore mass in the leaching slurry, a relatively low amount. Specifically, in the first stage of uranium leaching, the mass of sulfuric acid was 12% of the ore mass in the leaching slurry, and in the second stage, it was 6%. It is evident that the uranium ore leaching method provided in Example 3 can reduce acid consumption. Furthermore, the uranium grade of the leaching residue obtained in Example 3 was 0.012%, and the uranium leaching rate was 85.54%, achieving a high uranium leaching rate while reducing acid consumption.

[0123] Example 4

[0124] A leaching method for high acid-consuming uranium ore includes the following steps:

[0125] The ore and water are mixed in a mass ratio of 1:2.5, and then placed in a mixer and stirred with a paddle to obtain a slurry.

[0126] The above slurry was graded using a sieve with a mesh size of 0.1 mm, separating it into coarse-grained ore of +0.1 mm and fine-grained ore of -0.1 mm.

[0127] The sieved +0.1mm coarse-grained ore is ground to a particle size <0.1mm to obtain a ground slurry.

[0128] The ground slurry is combined with the screened fine-grained ore to obtain the leaching slurry.

[0129] Adjust the concentration of the leaching slurry to a solid-liquid ratio of 1:2.

[0130] Ferric sulfate was added to the leaching slurry. The mass of ferric sulfate was 1.5% of the mass of the ore in the leaching slurry. The mixture was stirred for 15 minutes at a stirring speed of 250 r / min.

[0131] Oxidant MnO2 was added to the leaching slurry containing ferric sulfate to obtain an oxidized leaching slurry. The mass of the oxidant was 0.8% of the ore mass in the leaching slurry. The mixture was stirred for 15 minutes at a stirring speed of 250 r / min.

[0132] Concentrated sulfuric acid with a mass concentration of 98% was added to the oxidative leaching slurry using a continuous dripping method. The mass of sulfuric acid was 11% of the mass of the ore in the leaching slurry. The mixture was stirred for 1.5 minutes to carry out a first stage of uranium leaching.

[0133] The slurry obtained from uranium leaching is thickened to obtain a thickened supernatant and a thickened slurry.

[0134] A 4% sulfuric acid solution was added to the thick slurry, with the mass of the sulfuric acid being 7% of the mass of the ore in the leaching slurry. The mixture was stirred for 12 minutes at a stirring speed of 250 r / min to carry out the second stage of uranium leaching.

[0135] The slurry obtained from the second stage of uranium leaching was subjected to solid-liquid separation treatment to obtain a clear separation liquid and leaching residue.

[0136] The mass of sulfuric acid in the concentrated supernatant was determined, and the mass of sulfuric acid was 2% of the mass of ore in the leaching slurry. Sulfuric acid solution was added to the concentrated supernatant, and the mass of added sulfuric acid was 5% of the mass of ore in the leaching slurry, so that the mass of sulfuric acid was 7% of the mass of ore in the leaching slurry. It can be used as a leaching agent in subsequent two-stage leaching processes, for example, in Example 5 below.

[0137] As shown in Table 1, in Example 4, the mass of sulfuric acid used was 18% of the ore mass in the leaching slurry, a relatively low amount. Specifically, in the first stage of uranium leaching, the mass of sulfuric acid was 11% of the ore mass in the leaching slurry, and in the second stage, it was 7%. It is evident that the uranium ore leaching method provided in Example 4 can reduce acid consumption. Furthermore, the uranium grade of the leaching residue obtained in Example 4 was 0.0125%, and the uranium leaching rate was 84.84%, achieving a high uranium leaching rate while reducing acid consumption.

[0138] Example 5

[0139] The difference between Example 5 and Example 4 is that the sulfuric acid solution added to the concentrated slurry is the same as that added to the concentrated supernatant in Example 4. In other words, based on the concentrated supernatant obtained in Example 4, only 5% of the ore mass in the leaching slurry needs to be added to the concentrated supernatant to achieve a total sulfuric acid content of 7% of the ore mass in the leaching slurry.

[0140] As shown in Table 1, in Example 5, the mass of sulfuric acid used was 16% of the ore mass in the leaching slurry, a very low amount. Specifically, during the first stage of uranium leaching, the mass of sulfuric acid was 11% of the ore mass in the leaching slurry, and during the second stage, the added sulfuric acid was 5% of the ore mass in the leaching slurry. It is evident that the uranium ore leaching method provided in Example 5 can reduce acid consumption. Furthermore, the uranium grade of the leaching residue obtained in Example 5 was 0.012%, and the uranium leaching rate was 85.54%, achieving a high uranium leaching rate while reducing acid consumption.

[0141] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A leaching method for high acid-consuming uranium ore, characterized in that, Includes the following steps: Preparation of leaching pulp; High-valent iron salts were added to the leaching slurry and stirred. An oxidant is added to the leaching slurry to which the high-valent iron salt has been added to obtain an oxidized leaching slurry; Concentrated sulfuric acid was added to the oxidative leaching slurry and stirred for 1 to 2 minutes to carry out a first-stage uranium leaching. The slurry obtained from the uranium leaching process is thickened to obtain a thickened supernatant and a thickened slurry. Add sulfuric acid solution to the thick slurry and stir for 3 to 30 minutes to carry out two-stage uranium leaching; The slurry obtained from the two-stage uranium leaching process is subjected to solid-liquid separation treatment to obtain a clear separation liquid and leaching residue.

2. The leaching method according to claim 1, characterized in that, In the step of adding high-valent iron salts to the leaching slurry and stirring... The mass of the high-valence iron salt is 0.1% to 2.0% of the mass of the ore in the leaching pulp; Stir for 1 to 20 minutes at a stirring speed of 100 to 500 r / min.

3. The leaching method according to claim 1, characterized in that, The high-valent iron salts include ferric sulfate or ferric chloride; The oxidant includes MnO2.

4. The leaching method according to claim 1, characterized in that, The step of adding an oxidant to the leaching slurry containing the high-valent iron salt to obtain an oxidized leaching slurry includes: An oxidant is added to the leaching slurry containing the high-valent iron salt, wherein the mass of the oxidant is 0.2% to 3% of the mass of the ore in the leaching slurry; The oxidative leaching slurry is obtained by stirring at a speed of 100 r / min to 500 r / min for 1 min to 20 min.

5. The leaching method according to claim 1, characterized in that, In the step of adding concentrated sulfuric acid to the oxidative leaching slurry, The concentrated sulfuric acid has a mass concentration of 98%, and is added continuously dropwise. The mass of the added sulfuric acid is 3% to 15% of the mass of the ore in the leaching slurry.

6. The leaching method according to claim 1, characterized in that, Adding sulfuric acid solution to the thick slurry and stirring for 3 to 30 minutes to perform a two-stage uranium leaching step includes: A sulfuric acid solution with a mass concentration of 2% to 10% is added to the thick slurry. The mass of the added sulfuric acid is 2% to 8% of the mass of the ore in the leaching slurry. The mixture is stirred for 3 to 30 minutes at a stirring speed of 50 to 500 r / min to carry out a two-stage uranium leaching process.

7. The leaching method according to claim 1, characterized in that, Also includes: Determine the mass of sulfuric acid in the concentrated supernatant; A sulfuric acid solution is added to the concentrated supernatant so that the mass of sulfuric acid in the concentrated supernatant is 2% to 8% of the mass of the ore in the leaching pulp.

8. The leaching method according to any one of claims 1 to 7, characterized in that, The steps for preparing leaching pulp include: The ore and water are mixed and stirred at a mass ratio of 1:1 to 1:5 to obtain a slurry. The slurry is screened and classified to obtain coarse-grained ore and fine-grained ore; The coarse-grained ore is ground to obtain a ground slurry; The fine-grained ore is mixed with the ground slurry to obtain the leaching slurry.

9. The leaching method according to claim 8, characterized in that, The step of screening and classifying the slurry to obtain coarse-grained ore and fine-grained ore includes: The slurry is screened and classified using a sieve with a mesh size of 0.05 mm to 0.25 mm to obtain coarse-grained ore and fine-grained ore.

10. The leaching method according to claim 8, characterized in that, In the step of grinding the coarse-grained ore, the coarse-grained ore is ground to a particle size of less than 0.25 mm.

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