Method for judging feasibility of micro-particle uranium mineral nelson centrifugal gravity separation and separation method
By assessing the feasibility of Nelson centrifugal gravity separation for fine-grained uranium minerals and combining it with the Nelson centrifugal separation-shaking table separation-gravity tailings flotation process, the problems of high separation difficulty and low recovery rate of uranium minerals were solved, and a significant improvement in the U recovery rate of uranium concentrate was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NORTHEASTERN UNIV CHINA
- Filing Date
- 2022-12-19
- Publication Date
- 2026-06-26
AI Technical Summary
In processing uranium minerals in the Wengquangou area of Liaoning Province, existing technologies often encounter fine-grained uranium minerals that are closely associated with other minerals, making separation difficult and resulting in low uranium recovery rates. Existing processes, such as hydrocyclone classification followed by shaking table beneficiation, achieve a uranium concentrate U recovery rate of only about 35%.
The feasibility assessment method of Nelson centrifugal gravity separation for fine-grained uranium minerals was adopted. Through three Nelson centrifugal separation processes and shaking table separation-gravity tailings flotation, including parameter settings of the Nelson centrifugal separator and the use of flotation reagents, the preliminary enrichment and efficient recovery of uranium minerals were achieved.
It increased the U recovery rate of uranium concentrate to 62-65%, significantly improved the recovery efficiency of uranium resources, and solved the problem of sorting fine-grained uranium minerals.
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Figure CN116099646B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of mineral separation technology, specifically to a method for determining the feasibility of Nelson centrifugal gravity separation of fine-grained uranium minerals and a separation method, particularly to a method for determining the feasibility of Nelson centrifugal gravity separation of fine-grained uranium minerals, and a method for obtaining uranium concentrate through Nelson centrifugal beneficiation—shaking table beneficiation—gravity separation tailings flotation. Background Technology
[0002] Uranium ore is an important strategic resource and energy mineral in my country, and a fundamental raw material for the development of my country's nuclear industry. The development of the nuclear energy industry is inseparable from uranium resources. As of 2015, my country's uranium reserves were 199,100 tons, accounting for 3.37% of the world's reserves. my country's uranium resources remain scarce, and it is essential to rationally develop and utilize existing uranium mines. Currently, uranium mining in my country mainly uses acid leaching, alkaline leaching, and microbial leaching. However, for some low-grade and fine-grained uranium minerals, direct leaching is too costly. Before leaching, physical sorting methods can be used to enrich uranium elements, which can reduce subsequent leaching costs.
[0003] The uranium-boron-iron deposit in the Wengquangou area of Liaoning Province is a sedimentary metamorphic deposit with multiple associated elements. The main useful minerals in the ore are magnetite, boromagnesite, and uranium crystalline minerals. The Wengquangou boron-iron deposit has iron ore reserves of 218 million tons, accounting for 1% of the national iron ore reserves; B2O3 reserves of 21.84 million tons, accounting for 58.0% of the national total boron reserves; and uranium resources are roughly estimated at 13,585 tons. The associated relationships of iron, boron, and uranium minerals in this deposit are complex, making beneficiation difficult. The raw ore has a TFe grade of 30.65%, a B2O3 grade of 7.23%, and a U grade of 0.0048%. When processing this type of ore, the concentrator uses a two-stage grinding and four-stage magnetic separation process to obtain iron concentrate. The tailings from the second-stage magnetic separation are classified by hydrocyclones, and the overflow is boron concentrate. The tailings from the coarse magnetic separation, the first magnetic tailings, and the second magnetic tailings are classified by hydrocyclones. The classified sediment is then processed by shaking table beneficiation to obtain uranium concentrate. The uranium grade in the obtained uranium concentrate is 0.1-0.2%, and the uranium recovery rate is about 35%. Improving the uranium grade and uranium recovery rate in the uranium concentrate is an urgent problem to be solved.
[0004] Centrifugal concentrators are enhanced gravity separation equipment based on the centrifugal principle. In a highly enhanced gravity field, the gravity difference between different particles is greatly increased, which is conducive to the separation between light and heavy particles and achieves a better separation effect than in a natural gravity field.
[0005] The uranium minerals in the Wengquangou area of Liaoning Province have complex structures and fine particle sizes, generally ranging from 0.02 to 0.045 mm. They are closely associated with magnetite and borosilicate, making separation difficult. Currently, the concentrator uses a hydrocyclone classification-shaking table process, resulting in low uranium recovery rates in the uranium concentrate. At the beneficiation site, the -0.074 mm content in the second-stage grinding is 78-81%, and the -0.074 mm content in the second-stage magnetic separation tailings is 83-86%. Particle size analysis shows that uranium is mainly distributed in the -0.074 mm particle size range in the second-stage magnetic separation tailings and scavenging tailings. When entering the hydrocyclone classification, some fine uranium minerals enter the overflow, causing uranium loss and reducing uranium recovery. Summary of the Invention
[0006] Given the current situation where uranium minerals in uranium-boron iron ore are finely distributed, have complex associated relationships, and have low U grades, the current concentrators use hydrocyclone classification followed by shaking table beneficiation to obtain uranium concentrate from iron tailings, resulting in a U recovery rate of approximately 35%, leading to significant uranium resource loss. Based on ore characteristics and the specific gravity differences between fine-grained uranium minerals and other minerals, this invention aims to provide a method for assessing the feasibility of Nelson centrifugal gravity separation of fine-grained uranium minerals. Furthermore, it describes a method for obtaining uranium concentrate through a Nelson centrifugal beneficiation-shaking table beneficiation-gravity separation tailings flotation process. This simple process effectively assesses the feasibility of Nelson centrifugal gravity separation of fine-grained uranium minerals and improves the U recovery rate in uranium concentrate, providing guidance for existing uranium mineral beneficiation processes and achieving efficient uranium resource recovery.
[0007] The technical means employed in this invention are as follows:
[0008] The feasibility assessment method for Nelson centrifugal gravity separation of fine-grained uranium minerals includes:
[0009] Step 1: Take a representative fine-grained uranium ore sample, in which the content of -0.074mm is greater than 80%; the sample taken is 100-200g.
[0010] Step 2: Adjust the ore sample to a slurry concentration of 15-25% by solids mass, and separate it using a Nelson centrifugal concentrator with a centrifugal strength of 60-120G, a backwash water flow rate of 2-6L / min, and a feed rate of 30-60g / min to obtain Nelson concentrate I and Nelson tailings I.
[0011] Step 3: Nielsen tailings I are separated using a Nielsen centrifugal concentrator with a centrifugal strength of 60-120G, a backwash water flow rate of 2-6L / min, and a feed rate of 20-40g / min to obtain Nielsen concentrate II and Nielsen tailings II.
[0012] Step 4: Nielsen tailings II are separated using a Nielsen centrifugal concentrator with a centrifugal strength of 60-120G, a backwash water flow rate of 2-6L / min, and a feed rate of 10-30g / min to obtain Nielsen concentrate III and Nielsen tailings III.
[0013] Step 5: Determine the feasibility of Nelson centrifugal gravity separation for fine-grained uranium minerals:
[0014] If the uranium recovery rate in Nelson concentrate I is ≥60%, and the uranium enrichment ratio in Nelson concentrate I is ≥1.5 relative to the raw ore, the uranium enrichment ratio in Nelson concentrate II is ≥1.0, and the uranium enrichment ratio in Nelson concentrate III is <1.0, then it is determined that the fine-grained uranium mineral is suitable for roughing by Nelson centrifugal beneficiation to achieve the effect of preliminary enrichment of uranium resources.
[0015] If the uranium recovery rate in Nelson concentrate I is less than 60%, or the enrichment ratio of uranium in Nelson concentrate I, Nelson concentrate II, and Nelson concentrate III does not meet the above conditions, then it is determined that the fine-grained uranium mineral is not suitable for Nelson centrifugal beneficiation and cannot be initially enriched.
[0016] In the above steps, the Nelson centrifugal concentrator is the KC-MD3 Nelson centrifugal concentrator.
[0017] When determining whether fine-grained uranium minerals are suitable for Nelson centrifugal gravity separation to achieve preliminary enrichment of uranium resources, this invention also provides a method for separating fine-grained uranium minerals, comprising the following steps:
[0018] Step A: Take a fine-grained uranium ore sample with a -0.074mm content greater than 80%. Use a KC-MD3 Nelson centrifugal concentrator for separation. The pulp concentration is 15-25% solids by mass, the centrifugal force is 60-120G, the backwash water flow rate is 2-6L / min, and the feed rate is 30-60g / min. This yields Nelson concentrate I and Nelson tailings I. Alternatively, use a KC-CVD6 Nelson centrifugal concentrator with a feed concentration of 3-5%, a feed rate of 80-120kg / h, a centrifugal force of 60-90G, a backwash water flow rate of 15-25L / min, a pinch valve closing time of 4-6s, and a pinch valve opening time of 280-380ms. This yields Nelson concentrate I and Nelson tailings I.
[0019] Step B involves separating Nelson concentrate I using a shaking table. The shaking table feed concentration is 10-20%, the transverse slope is 0.5-1°, the stroke is 9-12 mm, the stroke rate is 280-360 times / minute, and the transverse water flow rate is 3-5 L / min. This process yields uranium concentrate I, shaking table middlings I, and shaking table tailings I.
[0020] Step C: Using Nelson tailings I and shaking table tailings I as flotation feed, uranium flotation is performed using one roughing and three cleaning stages. The solid mass percentage of the slurry in the first roughing stage is 20-30%. The slurry is stirred in the flotation machine for 5-10 minutes, then 400-1000 g / t of activator lead nitrate is added and stirred for 5-10 minutes. Then, 1200-2400 g / t of collector benzoyl hydroxamic acid is added and stirred for 5-10 minutes. Sodium hydroxide is added to adjust the pH to 8-10 and stirred for 5-10 minutes. Finally, 30-100 g / t of frother No. 2 oil is added and stirred for 3-5 minutes. Aeration flotation is then performed to obtain uranium roughing concentrate I and roughing tailings I. The rougher concentrate I is subjected to three cleaning processes. No flotation reagents are added during the cleaning stages. Before each cleaning process, the slurry is stirred for 3-5 minutes and then aerated flotation is performed to obtain uranium concentrate II, middlings I, middlings II and middlings III. The rougher tailings I, middlings I, middlings II and middlings III are combined into flotation tailings, and uranium concentrate I and uranium concentrate II are combined into uranium concentrate.
[0021] Compared with the prior art, the present invention has the following advantages:
[0022] 1. The feasibility of Nelson centrifugal gravity separation for fine-grained uranium minerals was determined by a three-stage Nelson centrifugal separation method. If the U recovery rate in Nelson concentrate I is ≥60%, and the U enrichment ratio in Nelson concentrate I is ≥1.5, the U enrichment ratio in Nelson concentrate II is ≥1.0, and the U enrichment ratio in Nelson concentrate III is <1.0, then it can be determined that the fine-grained uranium minerals are suitable for roughing using Nelson centrifugal separation. This method is simple, easy to implement, and convenient to operate.
[0023] 2. Fine-grained uranium minerals are initially enriched by Nelson centrifugal separation, and then gravity-separated uranium concentrate is obtained by shaking table cleaning. This process is simple, can effectively enrich uranium minerals, and achieve efficient recovery of uranium resources.
[0024] 3. By using a flotation process consisting of one rougher and three cleaners, fine-grained uranium minerals that cannot be recovered by gravity separation can be recovered from Nelson tailings and shaking table tailings to obtain flotation uranium concentrate, thereby improving the U recovery rate of uranium concentrate.
[0025] Based on the above reasons, this invention can be widely applied in fields such as mineral sorting. Attached Figure Description
[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0027] Figure 1This is a flowchart illustrating the feasibility assessment method for Nelson centrifugal reseparation of fine-grained uranium minerals in a specific embodiment of the present invention.
[0028] Figure 2 This is a flowchart illustrating the sorting method for fine-grained uranium minerals in a specific embodiment of the present invention. Detailed Implementation
[0029] It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this invention can be combined with each other. The invention will now be described in detail with reference to the accompanying drawings and embodiments. To make the objectives, technical solutions, and advantages of the embodiments of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0030] Example 1
[0031] This specific embodiment describes the feasibility of centrifugal gravity separation of fine-grained uranium minerals using the three-stage Nelson centrifugal separation method (steps 1-5, see appendix). Figure 1 Then, uranium concentrate is obtained through a Nelson centrifugal separation-shaking table separation-gravity tailings flotation process (steps A to C, see appendix). Figure 2 The fine-grained uranium ore sample was taken from the tailings of the second magnetic tailings scavenging plant. The fineness was -0.074 mm and the content was 83.65%. The U grade in the sample was 0.0088%.
[0032] The specific implementation steps for assessing the feasibility of the Nelson centrifugal gravity separation method for fine-grained uranium minerals are as follows:
[0033] Step 1: Take 100g of representative uranium ore sample from the tailings of the second magnetic tailings scavenging of the concentrator.
[0034] Step 2: Adjust the ore sample from Step 1 to a slurry concentration of 20% by mass of solids, and use a KC-MD3 Nelson centrifugal concentrator for separation. The centrifugation intensity is 90G, the backwash water flow rate is 2L / min, and the feed rate is 30g / min. This yields Nelson concentrate I and Nelson tailings I. The U grade in Nelson concentrate I is 0.0138%, and the U recovery rate is 79.60%.
[0035] Step 3: Take Nelson tailings I from Step 2 and separate them using a KC-MD3 Nelson centrifugal concentrator. The centrifugal strength is 90G, the backwash water flow rate is 2L / min, and the feed rate is 20g / min to obtain Nelson concentrate II and Nelson tailings II. The U grade in Nelson concentrate II is 0.0092%.
[0036] Step 4: Take the Nelson tailings II from Step 3 and separate them using a KC-MD3 Nelson centrifugal concentrator. The centrifugal strength is 90G, the backwash water flow rate is 2L / min, and the feed rate is 20g / min to obtain Nelson concentrate III and Nelson tailings III. The U grade in Nelson concentrate III is 0.0058%, and the U grade in Nelson tailings III is 0.0017%.
[0037] Step 5: Determine the feasibility of Nelson centrifugal gravity separation for fine-grained uranium minerals. The U recovery rate in Nelson concentrate I is 79.60%, and the U enrichment ratio in Nelson concentrate I is 1.57, the U enrichment ratio in Nelson concentrate II is 1.05, and the U enrichment ratio in Nelson concentrate III is 0.66, which indicates that the fine-grained uranium minerals are suitable for roughing with Nelson centrifugal separation to achieve the effect of preliminary enrichment of uranium resources. Then proceed to steps A to C.
[0038] A method for sorting fine-grained uranium minerals includes:
[0039] Step A: Take a representative sample of tailings from the two magnetic tailings scavenging processes and separate it using a KC-MD3 Nelson centrifugal concentrator. The sample fineness is -0.074mm and the content is 83.65%. Adjust the slurry concentration to 20% solids by mass, centrifuge intensity to 90G, backwash water flow rate to 2L / min, and feed rate to 30g / min to obtain Nelson concentrate I and Nelson tailings I. The U grade in Nelson concentrate I is 0.0138%, and the U recovery rate is 79.60%.
[0040] Step B involves using a LYN-1100×500 laboratory-grade slime shaking table to separate the Nelson concentrate I from Step A. The shaking table feed concentration is 15%, the transverse slope is 0.5°, the stroke is 10 mm, the stroke rate is 300 times / minute, and the transverse water flow rate is 3.8 L / min. This separation yields uranium concentrate I, shaking table middlings I, and shaking table tailings I. The uranium grade in uranium concentrate I is 0.2563%, and the uranium recovery rate is 38.96%.
[0041] Step C: Using Nelson tailings I and shaking table tailings I as flotation feed, uranium flotation is performed using a single roughing and three cleaning stages. The activator is lead nitrate, the collector is benzoyl hydroxamic acid, the modifier is sodium hydroxide, and the frother is No. 2 oil. The solids mass percentage of the primary roughing pulp is 20%. The mixture is stirred for 5 minutes in a laboratory flotation machine, then 500 g / t of lead nitrate is added and stirred for another 5 minutes. Then, 2000 g / t of benzoyl hydroxamic acid is added and stirred for another 5 minutes. Sodium hydroxide is added to adjust the pH to 9.0, and the mixture is stirred for another 5 minutes. Finally, 50 g / t of No. 2 oil is added and stirred for 3 minutes. Aeration flotation is then performed to obtain uranium roughing concentrate I and roughing tailings I. The rougher concentrate I was subjected to three cleaning stages, without the addition of flotation reagents. Before each cleaning stage, the slurry was stirred for 3 minutes for aerated flotation, yielding uranium concentrate II, middlings I, middlings II, and middlings III. The uranium grade in uranium concentrate II was 0.0793%, with a uranium recovery rate of 25.32%. The rougher tailings I, middlings I, middlings II, and middlings III were combined into flotation tailings, and uranium concentrate I and uranium concentrate II were combined into uranium concentrate. The uranium concentrate had a uranium grade of 0.1364%, with a uranium recovery rate of 64.28%.
[0042] In this invention example, the feasibility of Nelson centrifugal gravity separation for fine-grained uranium minerals is first determined. The U recovery rate in Nelson concentrate I is 79.60%, and relative to the raw ore, the U enrichment ratio in Nelson concentrate I is 1.57, in Nelson concentrate II it is 1.05, and in Nelson concentrate III it is 0.66. This indicates that the fine-grained uranium minerals are suitable for roughing using Nelson centrifugal concentrators, thereby achieving preliminary enrichment of uranium resources. Next, the uranium concentrate obtained using the Nelson centrifugal concentrator-shaking table concentrator-gravity tailings flotation process has a U grade of 0.1364% and a U recovery rate of 64.28%. The feasibility assessment method for Nelson centrifugal gravity separation of uranium minerals is described below. Figure 1 The uranium mineral sorting process flow is shown below. Figure 2 The results of the feasibility assessment of the Nilsson centrifugal gravity separation method for uranium minerals are shown in Table 1, and the results of the uranium mineral separation process flow are shown in Table 2.
[0043] Table 1. Results of the Nelson centrifugal recombination feasibility assessment method for uranium minerals in Example 1.
[0044] Serial Number name Yield / % U grade / % U recovery rate / % (1) raw ore 100.00 0.0088 100.00 (2) Nelson Concentrate I 50.76 0.0138 79.60 (3) Nelson Concentrate II 9.86 0.0092 10.31 (4) Nelson Concentrate III 5.13 0.0058 3.38 (5) Nelson Tailings III 34.25 0.0017 6.71
[0045] Table 2. Results of uranium mineral sorting process in Example 1
[0046] Serial Number name Yield / % U grade / % U recovery rate / % (1) raw ore 100.00 0.0088 100.00 (2) Nelson Concentrate I 50.76 0.0138 79.60 (3) Nelson Tailings I 49.24 0.0036 20.40 (4) Uranium Concentrate I 1.34 0.2563 38.96 (5) Shaking table ore I 3.59 0.0216 8.81 (6) Shaking table tailings I 45.83 0.0061 31.83 (7) Flotation feed 95.07 0.0048 52.23 (8) Uranium Concentrate II 2.81 0.0793 25.32 (9) flotation tailings 92.26 0.0026 26.91 (10) Uranium concentrate 4.15 0.1364 64.28
[0047] Example 2
[0048] This specific embodiment describes the feasibility of centrifugal gravity separation of fine-grained uranium minerals using the three-stage Nelson centrifugal separation method (steps 1-5, see appendix). Figure 1Then, uranium concentrate is obtained through a Nelson centrifugal separation-shaking table separation-gravity tailings flotation process (steps A to C, see appendix). Figure 2 The fine-grained uranium ore samples were taken from the tailings of the second magnetic tailings scavenging process at the concentrator. The uranium grade in the feed sample from the KC-MD3 Nelson centrifugal concentrator was 0.0088%, and the fineness was -0.074 mm with a content of 83.65%, which was the same as the sample in Example 1. The uranium grade in the feed sample from the KC-CVD6 Nelson centrifugal concentrator was 0.0056%, and the fineness was -0.074 mm with a content of 85.40%.
[0049] The specific implementation steps for assessing the feasibility of the Nelson centrifugal gravity separation method for fine-grained uranium minerals are as follows:
[0050] Step 1: Take 100g of representative uranium ore sample from the tailings of the second magnetic tailings scavenging of the concentrator.
[0051] Step 2: Adjust the ore sample from Step 1 to a slurry concentration of 20% by mass of solids, and use a KC-MD3 Nelson centrifugal concentrator for separation. The centrifugal force is 60G, the backwash water flow rate is 5L / min, and the feed rate is 30g / min. This yields Nelson concentrate I and Nelson tailings I. The U grade in Nelson concentrate I is 0.0174%, and the U recovery rate is 66.65%.
[0052] Step 3: Take Nelson tailings I from Step 2 and separate them using a KC-MD3 Nelson centrifugal concentrator. The centrifugal strength is 60G, the backwash water flow rate is 5L / min, and the feed rate is 20g / min to obtain Nelson concentrate II and Nelson tailings II. The U grade in Nelson concentrate II is 0.0101%.
[0053] Step 4: Take the Nelson tailings II from Step 3 and separate them using a KC-MD3 Nelson centrifugal concentrator. The centrifugal strength is 60G, the backwash water flow rate is 5L / min, and the feed rate is 20g / min to obtain Nelson concentrate III and Nelson tailings III. The U grade in Nelson concentrate III is 0.0063%, and the U grade in Nelson tailings III is 0.0026%.
[0054] Step 5: Determine the feasibility of Nelson centrifugal gravity separation for fine-grained uranium minerals. The U recovery rate in Nelson concentrate I is 66.65%, and the U enrichment ratio in Nelson concentrate I is 1.98, the U enrichment ratio in Nelson concentrate II is 1.15, and the U enrichment ratio in Nelson concentrate III is 0.72, which indicates that the fine-grained uranium minerals are suitable for roughing by Nelson centrifugal separation, thereby achieving the effect of preliminary enrichment of uranium resources. Then proceed to steps A to C.
[0055] A method for sorting fine-grained uranium minerals includes:
[0056] Step A: Take a representative fine-grained uranium ore sample and separate it using a KC-CVD6 Nelson centrifugal concentrator. The sample fineness is -0.074mm and the content is 85.40%. The feed concentration is 3.53%, the feed rate is 82.67kg / h, the centrifugal strength is 80G, the backwash water flow rate is 15L / min, the clamp valve closing time is 4s, and the clamp valve opening time is 360ms. Nelson concentrate I and Nelson tailings I are obtained. The uranium grade in the Nelson concentrate is 0.0088%, and the uranium recovery rate is 61.90%.
[0057] Step B involves using a LYN-1100×500 laboratory-grade slime shaking table to perform shaking separation of the Nelson concentrate from Step A. The shaking table feed concentration is 15%, the transverse slope is 0.5°, the stroke is 10 mm, the stroke rate is 300 times / minute, and the transverse water flow rate is 4.2 L / min. This separation yields uranium concentrate I, shaking table middlings I, and shaking table tailings I. The uranium grade in uranium concentrate I is 0.1876%, and the uranium recovery rate is 34.20%.
[0058] Step C: Using Nelson tailings I and shaking table tailings I as flotation feed, uranium flotation is performed using a single roughing and three cleaning stages. The activator is lead nitrate, the collector is benzoyl hydroxamic acid, the modifier is sodium hydroxide, and the frother is No. 2 oil. The solids mass percentage of the primary roughing pulp is 20%. The mixture is stirred for 5 minutes in a laboratory flotation machine, then 500 g / t of lead nitrate is added and stirred for another 5 minutes. Then, 2000 g / t of benzoyl hydroxamic acid is added and stirred for another 5 minutes. Sodium hydroxide is added to adjust the pH to 9.0, and the mixture is stirred for another 5 minutes. Finally, 50 g / t of No. 2 oil is added and stirred for 3 minutes. Aeration flotation is then performed to obtain uranium roughing concentrate I and roughing tailings I. The rougher concentrate I was subjected to three cleaning stages, without the addition of flotation reagents. Before each cleaning stage, the slurry was stirred for 3 minutes for aerated flotation, yielding uranium concentrate II, middlings I, middlings II, and middlings III. The uranium grade in uranium concentrate II was 0.0624%, with a uranium recovery rate of 28.04%. The rougher tailings I, middlings I, middlings II, and middlings III were combined into flotation tailings, and uranium concentrate I and uranium concentrate II were combined into uranium concentrate. The uranium concentrate had a uranium grade of 0.1315%, with a uranium recovery rate of 62.64%.
[0059] In this invention example, the feasibility of Nelson centrifugal gravity separation for fine-grained uranium minerals is first determined. The U recovery rate in Nelson concentrate I is 66.65%, and relative to the raw ore, the U enrichment ratio in Nelson concentrate I is 1.98, in Nelson concentrate II it is 1.15, and in Nelson concentrate III it is 0.72. This indicates that the fine-grained uranium minerals are suitable for roughing using Nelson centrifugal beneficiation, thereby achieving preliminary enrichment of uranium resources. Next, the uranium concentrate obtained using the Nelson centrifugal beneficiation-shaking table beneficiation-gravity tailings flotation process has a U grade of 0.1315% and a U recovery rate of 62.64%. The feasibility assessment method for Nelson centrifugal gravity separation of uranium minerals is described below. Figure 1 The uranium mineral sorting process flow is shown below. Figure 2 The results of the feasibility assessment of the Nelson centrifugal gravity separation method for uranium minerals are shown in Table 3, and the results of the uranium mineral separation process flow are shown in Table 4.
[0060] Table 3. Results of the feasibility assessment method for uranium mineral Nelson centrifugal recombination in Example 2.
[0061] Serial Number name Yield / % U grade / % U recovery rate / % (1) raw ore 100.00 0.0088 100.00 (2) Nelson Concentrate I 33.71 0.0174 66.65 (3) Nelson Concentrate II 12.46 0.0101 14.30 (4) Nelson Concentrate III 7.63 0.0063 5.47 (5) Nelson Tailings III 46.20 0.0026 13.58
[0062] Table 4. Results of uranium mineral sorting process in Example 2
[0063]
[0064]
[0065] The present invention describes a method for determining the feasibility of centrifugal gravity separation of fine-grained uranium minerals through three Nelson centrifugal separation processes, and then obtaining uranium concentrate through a Nelson centrifugal separation-shaking table separation-gravity separation tailings flotation process. The uranium concentrate obtained has a U grade of 0.13-0.14% and a U recovery rate of 62-65%, which is higher than the 35% observed on-site.
[0066] Compared with existing technologies, this invention assesses the feasibility of Nelson centrifugal gravity separation for fine-grained uranium minerals. The process involves Nelson centrifugal concentrator-shaking table concentrate-gravity tailings flotation to obtain uranium concentrate. The assessment demonstrates that the Nelson centrifugal concentrator can initially enrich and recover fine-grained uranium minerals from the concentrator, resulting in a final uranium concentrate with a U grade of 0.13–0.14% and a U recovery rate of 62–65%. This invention combines Nelson centrifugal concentrator, shaking table, and flotation methods, considering the density, particle size, and surface characteristics of the minerals, to obtain a uranium concentrate with a higher U grade, improving the U recovery rate. It provides a new method for the effective separation of fine-grained uranium minerals and can guide existing fine-grained uranium mineral beneficiation processes.
[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for sorting fine-grained uranium minerals, characterized in that, include: Step 1: Take a representative fine-grained uranium ore sample, in which the content of -0.074 mm is greater than 80%; Step 2: Adjust the ore sample to a slurry concentration of 15-25% by solids mass, and separate it using a Nelson centrifugal concentrator with a centrifugal strength of 60-120 G, a backwash water flow rate of 2-6 L / min, and a feed rate of 30-60 g / min to obtain Nelson concentrate I and Nelson tailings I. Step 3: Nielsen tailings I are separated using a Nielsen centrifugal concentrator with a centrifugal strength of 60-120 G, a backwash water flow rate of 2-6 L / min, and a feed rate of 20-40 g / min to obtain Nielsen concentrate II and Nielsen tailings II. Step 4: Nielsen tailings II are separated using a Nielsen centrifugal concentrator with a centrifugal strength of 60-120 G, a backwash water flow rate of 2-6 L / min, and a feed rate of 10-30 g / min to obtain Nielsen concentrate III and Nielsen tailings III. Step 5: Determine the feasibility of Nelson centrifugal gravity separation for fine-grained uranium minerals: If the uranium recovery rate in Nelson concentrate I is ≥60%, and the uranium enrichment ratio in Nelson concentrate I is ≥1.5 relative to the raw ore, the uranium enrichment ratio in Nelson concentrate II is ≥1.0, and the uranium enrichment ratio in Nelson concentrate III is <1.0, then it is determined that the fine-grained uranium mineral is suitable for roughing by Nelson centrifugal beneficiation to achieve the effect of preliminary enrichment of uranium resources. If the uranium recovery rate in Nelson concentrate I is less than 60%, or the enrichment ratio of uranium in Nelson concentrate I, Nelson concentrate II, and Nelson concentrate III does not meet the above conditions, then it is determined that the fine-grained uranium mineral is not suitable for Nelson centrifugal beneficiation and cannot be initially enriched. When the Nelson centrifugal gravity separation feasibility assessment method determines that fine-grained uranium minerals are suitable for roughing using Nelson centrifugal beneficiation to achieve preliminary enrichment of uranium resources, the following separation method shall be adopted: Step A: Take a fine-grained uranium ore sample. The content of -0.074 mm in the fine-grained uranium ore sample is greater than 80%. Use a Nelson centrifugal separator to separate the ore and obtain Nelson concentrate I and Nelson tailings I. Step B involves using a shaking table to separate Nelson concentrate I into uranium concentrate I, shaking table middlings I, and shaking table tailings I. Step C: Using Nelson tailings I and shaking table tailings I as flotation feed, uranium flotation is performed using one roughing and three cleaning processes. During the first roughing process, lead nitrate activator is added at a rate of 400-1000 g / t; benzoic acid collector is added at a rate of 1200-2400 g / t; sodium hydroxide is added to adjust the pH to 8-10; and frother No. 2 oil is added at a rate of 30-100 g / t. The first roughing process yields uranium roughing concentrate I and roughing tailings I. The three cleaning processes yield uranium concentrate II, middlings I, middlings II, and middlings III. Roughing tailings I, middlings I, middlings II, and middlings III are combined into flotation tailings, and uranium concentrate I and uranium concentrate II are combined into uranium concentrate.
2. The method for sorting fine-grained uranium minerals according to claim 1, characterized in that, In step 1, the mineral sample taken is 100~200 g.
3. The method for sorting fine-grained uranium minerals according to claim 1, characterized in that, The model of the Nelson centrifugal concentrator is KC-MD3.
4. The method for sorting fine-grained uranium minerals according to claim 1, characterized in that, In step A, a KC-MD3 Nelson centrifugal concentrator is used for separation. The solid mass concentration of the slurry is 15-25%, the centrifugal strength is 60-120 G, the backwash water flow rate is 2-6 L / min, and the feed rate is 30-60 g / min, to obtain Nelson concentrate I and Nelson tailings I.
5. The method for sorting fine-grained uranium minerals according to claim 1, characterized in that, In step A, a KC-CVD6 type Nelson centrifugal concentrator is used for separation. The feed concentration is 3~5%, the feed rate is 80~120 kg / h, the centrifugal intensity is 60~90 G, the backwash water flow rate is 15~25 L / min, the pinch valve closing time is 4~6s, and the pinch valve opening time is 280~380ms, to obtain Nelson concentrate I and Nelson tailings I.
6. The method for sorting fine-grained uranium minerals according to claim 1, characterized in that, In step B, the feed concentration of the shaking table is 10-20%, the transverse slope is 0.5-1°, the stroke is 9-12 mm, the stroke rate is 280-360 times / minute, and the transverse water flow rate is 3-5 L / min. The separation yields uranium concentrate I, shaking table middlings I, and shaking table tailings I.