Method for treating easily-argillized wrapped uranium-containing native gel sulfur-molybdenum ore

Abstract

The invention belongs to the field of mineral metallurgy, and particularly relates to a method for treating easily-argillization wrapped uranium-containing raw rubber sulfur-molybdenum ore, which comprises the following steps: carrying out coarse crushing and fine crushing on the easily-argillization wrapped uranium-containing raw rubber sulfur-molybdenum ore, then carrying out first-stage grading to obtain first-stage fine silt and a first-stage material, carrying out coarse grinding treatment on the first-stage material, and then carrying out second-stage grading to obtain second-stage fine silt; performing fine grinding treatment on the second-section material to obtain a fine grinding material; the first-stage fine silt, the second-stage fine silt and the fine grinding material obtained in the step (1) are placed in alkali liquor, pressurization and positive-pressure alkaline leaching treatment are conducted by adopting an oxygen-containing atmosphere, the alkali liquor is an aqueous solution of alkali metal element hydroxide, the pH value of the positive-pressure alkaline leaching stage is controlled to be 10 or above, then solid-liquid separation is conducted, and molybdenum-rich leaching liquor and uranium-rich leaching residues are obtained; and the uranium-rich leaching residues obtained in the step (2) are subjected to acid leaching treatment, and uranium-rich leaching liquid is obtained. According to the method, efficient extraction of molybdenum and uranium can be achieved, and in addition, high-selectivity separation of molybdenum and uranium can be synchronously achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry and hydrometallurgy, and in particular relates to a method for treating a sludge-encapsulated uranium-containing primary colloidal sulfide-molybdenum ore. Background Art

[0002] In recent years, the inclusion type uranium-containing primary colloidal sulfide-molybdenum ore has been a hot research topic in the metallurgical industry. For example, many researchers have carried out a lot of research on the inclusion type uranium-molybdenum ore in the Hebei-Inner Mongolia mineralization belt in my country. The research of Ma Jia et al. (Study on the Occurrence State of Molybdenum in Oxidation Zone Ore of a Uranium Deposit, Uranium Mining and Metallurgy, Issue 3, 2018) shows that this type of uranium-molybdenum ore is strongly altered, with hydromicitization and chloritization being particularly developed, high clay content, easy to mud, and uneven grinding particles, which is not conducive to solid-liquid separation; the ore contains water-soluble molybdenum, and the mineral particle size is fine and scattered, which is not suitable for mineral processing. The research of Liu Kang et al. (Study on the occurrence state and leaching performance of a certain uranium-molybdenum associated ore, Uranium Mining and Metallurgy, Issue 2, 2017) shows that the lithology of uranium and molybdenum ores is mainly secondary rhyolite porphyry (light gray-blue gray-gray black, porphyritic structure, massive structure, strong silicification and hydromicitization, local limonite mineralization, and high organic matter and mud content. Yang Jianfei et al. (Recovery of molybdenum from a low-grade difficult-to-select uranium-containing molybdenum ore by heap leaching, Nonferrous Metals (Smelting Part), 2023 The research of the 2nd phase shows that about 80% of the molybdenum element is distributed in the fine particles of -100 mesh. There is no crystalline mineral in the molybdenum mineral. The embedded particle size is fine and it is mainly wrapped by limonite in the form of fine veins, which makes the separation and leaching of the ore difficult. In general, the properties of this type of ore are very complex. The target minerals are extremely finely embedded, mainly in the form of inclusion colloidal minerals, and the amorphous minerals have poor flotation properties. They cannot be dissociated by coarse grinding, and are easy to be muddy by fine grinding.

[0003] In summary, there are three difficulties in the treatment of the complex uranium-containing primary colloidal sulfide molybdenum ore: first, how to reduce the content of fine mud and improve the efficiency of solid-liquid separation on the basis of achieving the dissociation of mineral monomers; second, how to achieve the cracking, oxidation and leaching of the inclusion colloidal sulfide molybdenum ore; third, how to achieve the separation of uranium and molybdenum. Around the development of this type of complex uranium-molybdenum ore, since the conventional acid stirring leaching process has a molybdenum leaching rate as low as 40%, for this reason, the Chinese patent document with publication number CN106834674A proposes a direct oxygen pressure leaching process for the original ore, which uses oxygen or oxygen in the air to efficiently oxidize the colloidal sulfide molybdenum ore in the complex molybdenum ore at a certain temperature, effectively realizing the enhanced leaching of molybdenum, and the molybdenum leaching rate can be increased from 40% of the conventional process to more than 90%. In practice, due to the extremely fine distribution of molybdenum-containing minerals, according to the technical scheme disclosed in the prior art, the ore needs to be finely ground to -200 mesh, accounting for more than 60%, in order to achieve a molybdenum leaching rate of >80%. At the same time, this type of molybdenum ore is severely slimy, and fine grinding further exacerbates the difficulty of liquid-solid separation of the ore slurry after leaching, resulting in the need to add alkaline substances for neutralization before filtration, which leads to increased reagent consumption and metal loss.

[0004] It can be seen that the prior art has adopted the following methods for treating complex uranium-containing primary colloidal molybdenum ore: First, in order to achieve the monomer dissociation of the mineral, direct fine grinding to -100 mesh or even -200 mesh is adopted, which causes the easy-to-grind minerals to be over-crushed and produces a large amount of extremely fine mud, resulting in the clogging of the filter cloth by the fine mud and difficulty in solid-liquid separation; second, in order to achieve the leaching of molybdenum in the inclusion colloidal molybdenum ore, oxygen pressure acid leaching enhanced leaching method is adopted, and the leaching of difficult-to-leach molybdenum is achieved through high temperature, high pressure, high acid and high oxidation; third, in terms of uranium-molybdenum separation, the route of leaching first and then separation is adopted. Due to the complex composition of the leachate, especially after the oxygen pressure acid leaching enhanced process is adopted, the concentration of impurity ions in the leachate is greatly increased, resulting in various problems such as increased reagent consumption, increased three-phase substances, and difficulty in phase separation during the uranium-molybdenum extraction, separation and recovery process.

[0005] It can be seen that the existing technology still has many shortcomings in the treatment of easily muddy uranium-containing primary colloidal sulfide-molybdenum ore, especially in the grinding pretreatment technology and uranium-molybdenum separation method, which need further innovation. Summary of the invention

[0006] Aiming at the treatment of easily muddy encapsulated uranium-containing primary colloidal sulfide-molybdenum ore, a new pretreatment method and uranium-molybdenum separation method are provided, so as to realize the efficient treatment of this type of ore.

[0007] The easily muddy encapsulated uranium-containing primary colloidal sulfide molybdenum ore contains a large amount of clay minerals that are cemented or finely ground. At the same time, molybdenum mainly exists in the form of primary encapsulated colloidal sulfide molybdenum ore, which will affect the extraction rate of molybdenum and uranium and the extraction and separation selectivity of molybdenum and uranium. In view of the problem of unsatisfactory extraction rate and extraction selectivity of molybdenum and uranium caused by the characteristics of the mineral, the present invention provides the following technical solutions:

[0008] A method for treating easily muddy encapsulated uranium-containing primary colloidal sulfide-molybdenum ore, comprising the following steps:

[0009] Step (1): Multi-level classification

[0010] The easily muddy encapsulated uranium-containing primary colloidal sulfide molybdenum ore is coarsely crushed and finely crushed, and then the first stage classification is performed to obtain a first stage of fine mud and a first stage of material, the first stage of material is coarsely ground and then the second stage of classification is performed to obtain a second stage of fine mud and a second stage of material, and the second stage of material is finely ground to obtain a finely ground material;

[0011] Step (2): Selective Molybdenum Extraction

[0012] The first-stage fine mud, the second-stage fine mud and the fine abrasive obtained in step (1) are placed in an alkali solution and pressurized with an oxygen-containing atmosphere to perform a positive pressure alkali leaching treatment, wherein the alkali solution is an aqueous solution of an alkali metal hydroxide, and the pH value of the positive pressure alkali leaching stage is controlled to be above 10, followed by solid-liquid separation to obtain a molybdenum-rich leaching solution and a uranium-rich leaching residue;

[0013] Step (3): Selective uranium extraction

[0014] The uranium-enriched leaching residue obtained in step (2) is subjected to acid leaching to obtain a uranium-enriched leaching solution.

[0015] In view of the problem of unsatisfactory molybdenum-uranium extraction rate and extraction selectivity caused by the easy-to-mudify encapsulated uranium-containing primary colloidal sulfur-molybdenum mineralization characteristics, the present invention innovatively performs two-stage classification on the easy-to-mudify encapsulated uranium-containing primary colloidal sulfur-molybdenum ore, and further cooperates with the subsequent positive pressure alkali leaching treatment, so that unexpected synergy can be achieved, and the easy-to-mudify encapsulated uranium-containing primary colloidal sulfur-molybdenum mineralization characteristics can be adapted to achieve efficient extraction of molybdenum and uranium, and in addition, high-selective separation of molybdenum and uranium can be achieved simultaneously. The process of the present invention is simple, easy to implement, and has low components and few three waste products.

[0016] In the present invention, the content of clay minerals (kaolinite, hydromica, potassium feldspar, chlorite, etc.) in the uranium-containing primary colloidal sulfide molybdenum ore is relatively high, which can reach 5-15%, the Mo grade is 0.5-5% (further can be 0.6-1%), and the U grade is 0.05-0.5% (further can be 0.08-0.15%).

[0017] In the present invention, the combination of the multi-stage classification and the subsequent positive pressure alkaline leaching can synergistically adapt the physicochemical characteristics of the mineral of the present invention, and unexpectedly improve the extraction rate and extraction selectivity of molybdenum and uranium.

[0018] In step (1), the powder is crushed to a particle size of less than -1 to -3 mm.

[0019] Preferably, the first stage classification is carried out by wet screening or spiral classification.

[0020] Preferably, the first-stage fine mud refers to fine mud with particles of -100 mesh.

[0021] Preferably, the coarse grinding time is 5 to 20 minutes.

[0022] Preferably, the second-stage fine mud refers to fine mud with particles of -100 mesh.

[0023] Preferably, the fine grinding time is 30 to 60 minutes.

[0024] Preferably, the proportion of particles finely ground to a particle size of -100 mesh is more than 90%.

[0025] In the present invention, the alkali metal hydroxide is sodium hydroxide and / or potassium hydroxide.

[0026] Preferably, the concentration of the alkali metal hydroxide in the alkali solution is 0.5-1.0M.

[0027] Preferably, the alkali metal hydroxide in the alkali solution in the positive pressure alkali leaching stage is 5% to 10% of the mass of the ore.

[0028] In the present invention, the oxygen-containing atmosphere is oxygen and / or air.

[0029] Preferably, the temperature of the positive pressure alkali leaching treatment is 70 to 95° C., the oxygen partial pressure is 0.1 to 0.2 MPa, and the leaching time is 2 to 6 hours.

[0030] In the present invention, molybdenum can be extracted from the molybdenum-rich leachate based on conventional means. For example, the molybdenum-rich leachate can be subjected to extraction and stripping treatment to extract the molybdenum therein.

[0031] In the present invention, uranium can be extracted from the uranium-rich leaching residue based on conventional means. For example, an optional solution of the present invention is to use an acid leaching process to extract the uranium.

[0032] For example, in step (3), the acid solution used in the acid leaching stage is a sulfuric acid solution.

[0033] Preferably, the mass of sulfuric acid and uranium-rich leaching residue is 10-15%.

[0034] In the present invention, in step (3), the temperature of the acid leaching stage is 50-70° C. and the time is 1-4 hours.

[0035] In step (3), the acid leaching stage also allows the addition of an oxidant.

[0036] Preferably, the oxidant comprises at least one of oxygen, hydrogen peroxide or potassium permanganate;

[0037] Preferably, the amount of oxygen introduced is 2-8% of the mass of the uranium-enriched leaching slag, the amount of hydrogen peroxide added is 2-8% of the mass of the uranium-enriched leaching slag, and the amount of potassium permanganate added is 0.2-0.8% of the mass of the uranium-enriched leaching slag.

[0038] In the present invention, uranium can be recovered from the uranium-rich leaching solution based on conventional means, for example, the uranium-rich leaching solution is subjected to extraction or ion exchange treatment to extract the uranium therein.

[0039] Beneficial Effects

[0040] (1) Through the refined pretreatment method of "coarse crushing-fine crushing and classification-first stage coarse grinding and classification-second stage fine grinding and dissociation", further combined with positive pressure alkaline leaching treatment, the contradiction between the fine grinding and mudification of clay minerals and the difficulty in dissociation of inclusions can be effectively resolved, which not only realizes the physical separation of inclusions, but also minimizes the problem of over-grinding and mudification of materials. It can synergistically realize the efficient extraction of uranium and molybdenum in minerals with the above-mentioned physical and chemical characteristics, and can achieve selective separation.

[0041] (2) The present invention has strong practicability, high recovery rate of uranium and molybdenum resources, low overall processing cost, simple and feasible operation, and is easy for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0043] The present invention is further described below with reference to the embodiments, but the contents of the present invention are not limited to the described scope.

[0044] The present invention provides an optional method for treating easily muddy encapsulated uranium-containing primary colloidal sulfide molybdenum ore, the steps comprising:

[0045] (1) Ore fine pretreatment: First, the ore is coarsely crushed, then finely crushed, and the fine mud is separated and then enters the first stage of coarse grinding, and then the fine mud is further separated and enters the second stage of fine grinding.

[0046] (2) Leaching of molybdenum: The fine mud separated twice in step (1) and the final finely ground product are put into the molybdenum leaching process together, and the molybdenum is leached by sodium hydroxide + oxygen micro-pressure alkali method, and the molybdenum leachate is obtained by filtration and washing, and the filter cake is sent to the next step of treatment;

[0047] (3) Uranium leaching: The filter cake obtained in step (2) is subjected to a sulfuric acid + oxidant atmospheric pressure acid method to leach uranium, and the uranium leaching solution is obtained by filtering and washing, and the filter cake tail is discarded.

[0048] (4) Recovery of molybdenum: extracting molybdenum from the molybdenum leaching solution obtained in step (2) to obtain a qualified molybdenum solution.

[0049] (5) Uranium recovery: The uranium leaching solution obtained in step (3) is subjected to extraction or ion exchange to recover uranium to obtain a qualified uranium solution.

[0050] The step (1) is specifically as follows: the uranium-containing primary colloidal sulfide molybdenum ore is firstly coarsely crushed by a jaw crusher, and then finely crushed by a roller to a particle size of less than -1 to -3 mm. The finely crushed material is subjected to wet screening or spiral classification, and the fine mud of -100 mesh is separated for standby use. The coarse particle material enters the first stage of coarse grinding, and the coarse grinding time is 5 to 20 minutes. The material after the first stage of coarse grinding is subjected to wet screening or spiral classification, and the fine mud of -100 mesh is further separated for standby use. The coarse particle material enters the second stage of fine grinding, and the fine grinding time is 30 to 60 minutes, until the discharge particle size is -100 mesh, accounting for more than 90%.

[0051] Due to the particularity of the mineral composition of this type of uranium-containing primary colloidal sulfide molybdenum ore, there are a large number of clay minerals and molybdenum mineral inclusions. Under the existing grinding method, short-term coarse grinding cannot achieve inclusion dissociation and affect the leaching effect, and long-term fine grinding is prone to excessive mudification of clay minerals and affect the solid-liquid separation effect. For this reason, the present invention first adopts the two-stage classification process, which can significantly solve the mudification phenomenon and facilitate the monomer dissociation of minerals, laying the foundation for the leaching of molybdenum in inclusions. The ore refinement pretreatment method of the present invention can effectively solve the contradiction between the fine grinding mudification of clay minerals and the difficulty of dissociation of inclusions.

[0052] The step (2) specifically comprises: leaching molybdenum from the -100 mesh slurry obtained in step (1) by alkaline method, with a leaching liquid-solid ratio of (2-4):1, the leaching agent can be sodium hydroxide, the addition amount is 5%-10% of the mass of the ore, the leaching temperature is 70-95°C, the oxidant is oxygen, the oxygen partial pressure is 0.1-0.2MPa, leaching for 2-6h, then filtering, and washing twice with clean water with a liquid-solid ratio of 2:1.

[0053] In the present invention, under the combination of the above-mentioned graded treatment and pressurized alkaline leaching process, the existing uranium-molybdenum ore treatment process is to leach uranium and molybdenum into the solution at the same time, and then separate uranium and molybdenum from the uranium-molybdenum-containing solution. Different from this, the present invention can completely realize the separation of uranium and molybdenum in the leaching stage. First, sodium hydroxide is used as a leaching agent to strengthen the leaching of molybdenum by a micro-pressure enhanced alkaline method. Under the premise of fine pretreatment in step (1), assisted by appropriate leaching process conditions, a very high molybdenum leaching rate can be achieved. The main chemical reaction of the leaching process is as follows: MoS2+6NaOH+9 / 2O2=Na2MoO4+2Na2SO4+3H2O, and the separation of uranium and molybdenum can be completely realized in the leaching stage, avoiding various difficulties in the subsequent solution uranium and molybdenum separation in the existing method.

[0054] The step (3) specifically comprises: performing acid leaching of uranium from the filter cake obtained in step (2), wherein the leaching agent is sulfuric acid, and the addition amount is 10-15% of the mass of the ore; the oxidant is one of oxygen, hydrogen peroxide or potassium permanganate, wherein the oxygen introduction amount is 2-8% of the mass of the ore, the hydrogen peroxide addition amount is 2-8% of the mass of the ore, and the potassium permanganate addition amount is 0.2-0.8% of the mass of the ore; the leaching liquid-solid ratio is (1-3):1, the leaching temperature is 50-70°C, filtering after leaching for 1-4 hours, and washing twice with clean water with a liquid-solid ratio of 2:1.

[0055] The step (4) specifically comprises: recovering molybdenum from the molybdenum leaching solution obtained in step (2), and the recovery method is a common extraction process, which will not be described in detail here.

[0056] The step (5) specifically comprises: recovering molybdenum from the uranium leaching solution obtained in step (3). The recovery method is a common extraction or ion exchange process, which will not be described in detail here.

[0057] Example 1

[0058] The ore lithology of a certain inclusion-type uranium-bearing primary colloidal sulfur-molybdenum mine is mainly secondary rhyolite porphyry, followed by rhyolitic tuff and a small amount of cryptoexplosive hornblende; the ore is strongly altered, and most of the feldspar phenocrysts are altered to hydromica, kaolinite and chlorite; the matrix is ​​seriously viscous, silicified and hydromicatized, and contains carbon; the target minerals are extremely finely embedded, mainly colloidal minerals, amorphous minerals, poor flotation, cannot be dissociated by coarse grinding, and are easy to be muddy by fine grinding. The results of its complete chemical analysis are shown in Table 1.

[0059] Table 1 Analysis results of main chemical elements of a certain uranium-containing primary colloidal sulfide-molybdenum ore

[0060] Components U Mo <![CDATA[SiO2]]> Al Fe Ca As Mg S content / % 0.108 0.938 69.65 6.32 3.58 0.238 0.156 0.038 4.25

[0061] The method of the present invention for treating the easily sludged encapsulated uranium-containing primary colloidal sulfide-molybdenum ore comprises the following process steps:

[0062] (1) Ore fine pretreatment: The uranium-containing primary colloidal sulfide molybdenum ore is first crushed to -5 mm by a jaw crusher, and then crushed to a particle size of less than -1 mm by a roller. The crushed material is wet-screened to separate the -100 mesh fine mud (first stage fine mud) for use (first classification). The coarse particles enter the first stage of coarse grinding for 10 minutes. The materials after the first stage of coarse grinding are wet-screened (second classification), and the -100 mesh fine mud (second stage fine mud) is further separated for use. The coarse particles enter the second stage of fine grinding for 45 minutes. The particle size of the second stage fine grinding output is -100 mesh, accounting for 92.8% (fine grinding material).

[0063] (2) Leaching molybdenum: The -100 mesh particles (first stage fine mud, second stage fine mud and fine abrasive) obtained in step (1) are slurried to obtain a slurry, an aqueous sodium hydroxide solution is added to the slurry, and oxygen is introduced for pressurized leaching, wherein the leaching liquid-solid ratio is 2:1, the concentration of the aqueous sodium hydroxide solution can be 0.5-1M, the amount of sodium hydroxide added is 8% of the mass of the ore, the leaching temperature is 90°C, the oxygen partial pressure is 0.1 MPa, and the leaching is performed for 4 hours before filtering. The pH value of the leaching solution is 10.9, and the leaching solution is washed twice with clean water with a liquid-solid ratio of 2:1 to obtain a molybdenum leaching solution and U slag.

[0064] (3) Leaching uranium: The filter cake (U slag) obtained in step (2) is subjected to acid oxidation to leach uranium. The leaching agent is sulfuric acid, and the addition amount is 12% of the mass of the ore. The oxidant is hydrogen peroxide, and the addition amount is 3% of the mass of the ore. The leaching liquid-solid ratio is 1:1, and the leaching temperature is 50°C. After leaching for 2 hours, the mixture is filtered and washed twice with clean water at a liquid-solid ratio of 2:1 to obtain U leaching solution and tailings.

[0065] Final effect: In step 2, the leaching recovery rate of Mo (the leaching recovery rate refers to the percentage of molybdenum leached in step 2 to the total molybdenum) is 93.82%, the grade of Mo in the U slag is 0.058%, and the leaching rate of U is less than 0.5%;

[0066] In step 3, the uranium grade of the tailings is 0.009%, and the total uranium leaching recovery rate (referring to the percentage of U leached in step 3 to the total U) is 91.67%.

[0067] It can be seen that in the present invention, the highly efficient separation and extraction and recovery of Mo and U can be achieved through the process.

[0068] Comparative Example 1

[0069] Compared with Example 1, the only difference is that the ore fine pretreatment of step (1) is not carried out, and the uranium-molybdenum separation route of first alkali leaching of molybdenum and then acid leaching of uranium in steps (2) and (3) is not carried out. Instead, the ore is directly ground to a particle size of -100 mesh in one step, and then oxygen pressure acid leaching is carried out under the conditions of an initial sulfuric acid concentration of 30 g / L, a leaching temperature of 160°C, an oxygen partial pressure of 0.3 MPa, and a leaching time of 1 h. The leached slurry is difficult to filter, so carbide slag is added in the filtration stage to assist in filtration.

[0070] The results show that under the high temperature oxygen pressure leaching, the leaching effects of U and Mo are 90.74% and 90.94% respectively, which are not as good as the present invention. More importantly, it is impossible to achieve efficient selective separation of U and Mo in the leaching stage, and the process of separating uranium and molybdenum in the leaching solution stage is complicated and the production cost is high.

[0071] Comparative Example 2

[0072] Compared with Example 1, the only difference is that in step 1, the first stage separation and the second stage separation are omitted, and coarse crushing, fine crushing, coarse grinding and fine grinding are directly performed to obtain fine abrasives with a -100 mesh accounting for more than 90%, and other uranium and molybdenum leaching conditions are the same as in Example 1.

[0073] The results are as follows: the filtration efficiency in the leaching stage is low, the leaching rate of Mo in step 2 is 88.17%, and the recovery rate of U in step 3 is 89.81%. The leaching efficiency and element recovery effect are not as good as those of the present application.

[0074] Comparative Example 3

[0075] Compared with Example 1, the only difference is that the uranium-molybdenum separation route of first alkali leaching of molybdenum and then acid leaching of uranium in steps (2) and (3) is not carried out, but the fine material (first stage fine mud, second stage fine mud and fine abrasive) after multi-stage classification in step 1 is subjected to oxygen pressure acid leaching under the conditions of initial sulfuric acid concentration of 30 g / L, leaching temperature of 160°C, oxygen partial pressure of 0.3 MPa and leaching time of 1 h.

[0076] The materials after the classification treatment were subjected to oxygen pressure leaching treatment, and the leaching effects of U and Mo were 90.87% and 91.74% respectively, which were inferior to the present invention. More importantly, it was not possible to achieve efficient selective separation of U and Mo in the leaching stage.

[0077] Comparative Example 4

[0078] Compared with Example 1, the only difference is that the sodium hydroxide micro-pressure oxidation leaching in step (2) is not performed, and a normal pressure alkali stirring leaching process is adopted, that is, in step 2, the leaching stage is carried out under oxygen and the pressure is atmospheric pressure.

[0079] The study showed that in step 2, the leaching rate of Mo dropped to 76.01%, and the recovery rate of U in step 3 was also disturbed, dropping to 90.87%.

[0080] Comparative Example 5

[0081] Compared with Example 1, the only difference is that step (2) does not use sodium hydroxide micro-pressure oxidation leaching, that is, sodium carbonate is used to replace the sodium hydroxide, and the pH and other operations and parameters of the leaching stage are the same as those of Example 1.

[0082] The results show that in step 2, the leaching rate of Mo dropped to 91.56%, and the leaching rate of U reached 87.03%.

[0083] Comparative Example 6

[0084] Compared with Example 1, the only difference is that in step (2), the pH value in the leaching stage and the leaching end point is controlled to be 9, and the other operations and parameters are the same as those in Example 1.

[0085] The study showed that in step 2, the leaching rate of Mo dropped to 88.17%, and the leaching rate of U reached 4.78%, and efficient selective separation of U and Mo was not achieved.

[0086] Example 2

[0087] The ore lithology of a certain uranium-molybdenum mine is located in volcanic rocks, mainly composed of quartz, containing a small amount of illite and potassium feldspar and other minerals. The target minerals are mainly molybdenite / molybdenite and pitchblende, and there are a small amount of other metal minerals such as pyrite, sphalerite, hematite, galena, etc. The total content of clay minerals such as hydromica, kaolinite and chlorite is 8% of the ore mass. The molybdenum mineral has poor flotation properties, cannot be dissociated by coarse grinding, and is easy to be muddy by fine grinding. The results of its complete chemical analysis are shown in Table 3.

[0088] Table 3 Analysis results of main chemical elements of a uranium-molybdenum ore

[0089] Components U Mo <![CDATA[SiO2]]> Al Fe Ca As Mg S content / % 0.088 0.715 71.5 7.32 3.24 0.338 0.176 0.138 4.77

[0090] The method of the present invention for treating the easily sludged uranium-containing primary colloidal sulfide-molybdenum ore comprises the following process steps:

[0091] (1) Ore fine pretreatment: The uranium-containing primary colloidal sulfide molybdenum ore is first crushed to -8 mm by a jaw crusher, and then crushed to a particle size of less than -1 mm by a roller. The crushed material is wet-screened to separate the -100 mesh fine mud for later use (first classification). The coarse particles enter the first stage of coarse grinding for 12 minutes. The materials after the first stage of coarse grinding are wet-screened (second classification) to continue to separate the -100 mesh fine mud for later use. The coarse particles enter the second stage of fine grinding for 40 minutes. The particle size of the second stage of fine grinding is -100 mesh, accounting for 91.5%.

[0092] (2) Leaching molybdenum: The slurry of -100 mesh particles (fine mud and fine abrasive) obtained in step (1) was subjected to alkaline leaching of molybdenum, the liquid-to-solid ratio of the leaching was 2:1, the leaching agent was sodium hydroxide, the addition amount was 6% of the mass of the ore, the leaching temperature was 95°C, the oxidant was air, and the leaching was filtered after 18 hours. The pH value of the leaching solution was 10.7, and the leaching solution was washed twice with clean water with a liquid-to-solid ratio of 2:1 to obtain Mo leaching solution and U slag.

[0093] (3) Leaching uranium: The filter cake obtained in step (2) is subjected to acid leaching of uranium, wherein the leaching agent is sulfuric acid, the addition amount of which is 10% of the mass of the ore, the oxidant is potassium permanganate, the addition amount of which is 0.2% of the mass of the ore, the leaching liquid-solid ratio is 1:1, the leaching temperature is 60°C, and after leaching for 4 hours, the mixture is filtered and washed twice with clean water at a liquid-solid ratio of 2:1 to obtain U leaching solution and tailings.

[0094] Final effect: In step 2, the molybdenum grade in the U slag is 0.049%, the molybdenum leaching rate is 93.15%, and the U leaching rate is less than 0.5%. In step 3, the uranium grade of the tailings is 0.006%, and the uranium leaching rate is 93.18%.

[0095] The present invention provides a method for treating uranium-containing primary colloidal sulfide-molybdenum ore that is easily muddied and encapsulated. The method first adopts a refined pretreatment method of "coarse crushing-fine crushing and classification-first stage coarse grinding and classification-second stage fine grinding and dissociation", which effectively solves the contradiction between the fine grinding and muddiing of clay minerals and the difficulty of dissociation of inclusions, and greatly improves the efficiency of subsequent solid-liquid separation of leached ore slurry; then, a step-by-step leaching process of first leaching molybdenum with sodium hydroxide micro-pressure oxidation and then leaching uranium with sulfuric acid is adopted to obtain molybdenum-containing and uranium-containing solutions respectively, and innovatively realizes the separation of uranium and molybdenum in the leaching stage, avoiding various difficulties encountered in the existing technology for separating uranium and molybdenum in the leaching solution. The present invention is highly practical and can effectively treat this type of complex uranium-containing primary colloidal sulfide-molybdenum ore of different grades, with a high extraction rate of uranium and molybdenum, avoiding the problems of difficult solid-liquid separation, high production cost or low recovery rate in other processes, with low overall production cost, feasible operation, and easy industrial production.

Claims

1. A method for treating easily sludged encapsulated uranium-containing primary colloidal sulfide molybdenum ore, characterized in that the steps include: Step (1): Multi-level classification The easily muddy encapsulated uranium-containing primary colloidal sulfide molybdenum ore is coarsely crushed and finely crushed, and then the first stage classification is performed to obtain a first stage of fine mud and a first stage of material, the first stage of material is coarsely ground and then the second stage of classification is performed to obtain a second stage of fine mud and a second stage of material, and the second stage of material is finely ground to obtain a finely ground material; Step (2): Selective Molybdenum Extraction The first-stage fine mud, the second-stage fine mud and the fine abrasive obtained in step (1) are placed in an alkali solution and pressurized with an oxygen-containing atmosphere to perform a positive pressure alkali leaching treatment, wherein the alkali solution is an aqueous solution of an alkali metal hydroxide, and the pH value of the positive pressure alkali leaching stage is controlled to be above 10, followed by solid-liquid separation to obtain a molybdenum-rich leaching solution and a uranium-rich leaching residue; Step (3): Selective uranium extraction The uranium-enriched leaching residue obtained in step (2) is subjected to acid leaching to obtain a uranium-enriched leaching solution.

2. The method for treating the easily sludged encapsulated uranium-containing primary colloidal sulfide-molybdenum ore according to claim 1, characterized in that: The clay mineral content in uranium-containing primary colloid-sulfide molybdenum ore is 5-15%, the Mo grade is 0.5-5%, and the U grade is 0.05-0.5%.

3. The method for treating the easily sludged encapsulated uranium-containing primary colloidal sulfide-molybdenum ore according to claim 1, characterized in that: In step (1), the powder is crushed to a particle size of less than -1 to -3 mm; Preferably, the first stage classification is performed by wet screening or spiral classification; Preferably, the first stage fine mud refers to fine mud with particles of -100 mesh; Preferably, the coarse grinding time is 5 to 20 minutes; Preferably, the second-stage fine mud refers to fine mud with particles of -100 mesh; Preferably, the fine grinding time is 30 to 60 minutes; Preferably, the proportion of particles finely ground to a particle size of -100 mesh is more than 90%.

4. The method for treating the easily sludged encapsulated uranium-containing primary colloidal sulfide-molybdenum ore according to claim 1, characterized in that: The alkali metal hydroxide is sodium hydroxide and / or potassium hydroxide; Preferably, the concentration of the alkali metal hydroxide in the alkali solution is 0.5 to 1.0 M; Preferably, the alkali metal hydroxide in the alkali solution in the positive pressure alkali leaching stage is 5% to 10% of the mass of the ore.

5. The method for treating the easily sludged encapsulated uranium-containing primary colloidal sulfide-molybdenum ore according to claim 1, characterized in that: The oxygen-containing atmosphere is oxygen and / or air; Preferably, the temperature of the positive pressure alkali leaching treatment is 70 to 95° C., the oxygen partial pressure is 0.1 to 0.2 MPa, and the leaching time is 2 to 6 hours.

6. The method for treating the easily sludged encapsulated uranium-containing primary colloidal sulfide-molybdenum ore according to claim 1, characterized in that: The molybdenum-rich leaching solution is subjected to extraction and stripping treatment to extract the molybdenum therein.

7. The method for treating the easily sludged encapsulated uranium-containing primary colloidal sulfide-molybdenum ore according to claim 1, characterized in that: In step (3), the acid solution used in the acid leaching stage is a sulfuric acid solution; Preferably, the mass of sulfuric acid and uranium-rich leaching residue is 10-15%.

8. The method for treating the easily sludged encapsulated uranium-containing primary colloidal sulfide-molybdenum ore according to claim 1, characterized in that: In step (3), the temperature of the acid leaching stage is 50-70° C. and the time is 1-4 hours.

9. The method for treating the easily sludged encapsulated uranium-containing primary colloidal sulfide-molybdenum ore according to claim 1, 7 or 8, characterized in that: In step (3), an oxidant is also added during the acid leaching stage; Preferably, the oxidant comprises at least one of oxygen, hydrogen peroxide or potassium permanganate; Preferably, the amount of oxygen introduced is 2-8% of the mass of the uranium-enriched leaching slag, the amount of hydrogen peroxide added is 2-8% of the mass of the uranium-enriched leaching slag, and the amount of potassium permanganate added is 0.2-0.8% of the mass of the uranium-enriched leaching slag.

10. The method for treating the easily sludged encapsulated uranium-containing primary colloidal sulfide-molybdenum ore according to claim 1, characterized in that: The uranium-rich leaching solution is subjected to extraction or ion exchange treatment to extract the uranium therein.

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