A processing method for lithium-gallium-rich coal gangue
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA UNIV OF MINING & TECH
- Filing Date
- 2024-10-29
- Publication Date
- 2026-06-23
Smart Images
Figure CN119216090B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of coal-based solid waste resource utilization technology, and particularly relates to a method for treating lithium gallium-rich coal gangue. Background Technology
[0002] my country has abundant coal reserves, and a large amount of coal-related solid waste is generated during the mining and sorting process. Coal gangue is the most abundant type of coal gangue. If it is not treated in time, it will not only cause huge pollution to the environment, but also waste the potential value contained in coal gangue.
[0003] The main uses of coal gangue include: direct backfilling, combustion for power generation, use as building material, use as chemical raw material, and extraction of valuable elements.
[0004] However, existing utilization processes are relatively crude in treating coal gangue, resulting in a low resource utilization rate of coal gangue. Summary of the Invention
[0005] Based on the above analysis, the present invention aims to provide a method for processing lithium gallium-rich coal gangue, in order to solve the problem of low resource utilization rate of coal gangue in the prior art.
[0006] The objective of this invention is mainly achieved through the following technical solutions.
[0007] This invention provides a method for processing lithium gallium-rich coal gangue, comprising the following steps:
[0008] Step 1: Screen the coal gangue raw material to obtain oversize gangue and undersize gangue;
[0009] Step 2: Pre-sort the gangue on the screen to obtain lithium-gallium-rich concentrate and iron-rich tailings;
[0010] Step 3: Crush the undersize gangue and sorted concentrate to obtain a crushed mixture;
[0011] Step 4: Magnetic roasting of the crushed mixture to obtain the roasted product;
[0012] Step 5: Perform magnetic separation on the roasting products to obtain magnetic tailings and iron-rich magnetic concentrate;
[0013] Step 6: Mix the magnetic separation tailings with the roasting aid and then perform activation roasting, acid leaching and filtration in sequence to obtain leaching residue and lithium gallium leaching solution;
[0014] Step 7: Separate and purify the lithium gallium leaching solution to obtain metallic lithium and metallic gallium, thus completing the treatment of lithium gallium-rich coal gangue.
[0015] Furthermore, step 3 includes the following steps:
[0016] Step 31: Use a crusher to crush the undersize gangue and the sorted concentrate to obtain crushed particles;
[0017] Step 32: Grind and dissociate the particles after primary crushing using a grinding mill to obtain a crushed mixture.
[0018] Furthermore, in step 31, the particle size of the crushed particles is less than 0.5 mm.
[0019] Furthermore, in the crushed mixture, particles with a size range of -0.074 mm account for more than 90%.
[0020] Furthermore, in step 4, the magnetic calcination temperature is 450–550℃, the magnetic calcination time is 15–45 min, and the magnetic calcination atmosphere is air or nitrogen.
[0021] Furthermore, in step 5, the magnetic sorting intensity is 200–400 mT.
[0022] Furthermore, in step 6, the activation roasting temperature is 600–800℃, and the activation roasting time is 1–2 hours.
[0023] Furthermore, in step 6, the roasting aid includes one or two of NaCl, CaCl2, Na2CO3, CaO, CaF2, and NH4Cl in any proportion, and the mass ratio of the roasting aid to the magnetic separation tailings is 0.5 to 1:1.
[0024] Furthermore, in step 6, nitric acid, hydrochloric acid, sulfuric acid, citric acid, or oxalic acid are used as the acid leaching solution. The concentration of the acid leaching solution is 2-5 mol / L, the liquid-to-solid ratio is 1:5-10, the leaching time is 1-3 hours, and the leaching temperature is 60-80℃.
[0025] Furthermore, the iron-rich tailings obtained in step 2 and the iron-rich magnetic concentrate obtained in step 5 are used as raw materials for ironmaking; and / or, the leaching residue obtained in step 6 is used as a raw material for the preparation of water glass.
[0026] Compared with the prior art, the present invention can achieve at least the following beneficial effects:
[0027] A) The method for processing lithium gallium-rich coal gangue provided by this invention can achieve efficient utilization of coal gangue and has the characteristics of simple process, wide adaptability, high practicality and low cost.
[0028] B) The method for processing lithium-gallium-rich coal gangue provided by this invention, on the one hand, pre-sorts the gangue with larger particle size on the screen, pre-removing a portion of the iron-rich tailings, which not only achieves pre-enrichment of lithium-gallium but also reduces the processing volume of subsequent processes; on the other hand, through magnetization roasting, weakly magnetic pyrite is transformed into strongly magnetic pyrrhotite, further separating the iron-rich magnetic concentrate, thereby reducing the adverse effects of iron in subsequent leaching processes; furthermore, the magnetic tailings are activated and roasted, which effectively improves the leaching activity and efficiency of the magnetic tailings; finally, acid leaching is used to extract lithium-gallium from the magnetic tailings, a simple process that effectively improves extraction efficiency and ensures the efficient and high-value utilization of coal gangue.
[0029] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained through the embodiments described and the accompanying drawings, which are particularly pointed out. Attached Figure Description
[0030] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.
[0031] Figure 1 A flowchart of a method for processing lithium gallium-rich coal gangue provided by the present invention;
[0032] Figure 2 This is a schematic diagram of the processing system in the method for processing lithium gallium-rich coal gangue provided by the present invention;
[0033] Figure 3 This is a schematic diagram of the dust removal process in the method for treating lithium gallium-rich coal gangue provided by the present invention.
[0034] Figure 4 XRD patterns of coal gangue raw material and coal gangue before and after magnetization roasting in Examples 1-3.
[0035] Figure label:
[0036] 1-Screening unit; 2-Pre-sorting unit; 3-Crusher; 4-Grinding mill; 5-Magnetic roasting unit; 6-Magnetic sorting unit; 7-Activation roasting unit; 8-Acid leaching unit; 9-Mounting rod; 10-Reciprocating guide rail; 11-Reciprocating sliding filter screen; 12-Mounting sleeve. Detailed Implementation
[0037] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.
[0038] This invention provides a method for processing lithium-gallium-rich coal gangue, see [link to relevant documentation]. Figure 1 It includes the following steps:
[0039] Step 1: Use a grading screen (e.g., a 30mm grading screen) to screen the coal gangue raw material to obtain oversize gangue and undersize gangue;
[0040] Step 2: Based on the differences in the X-ray fluorescence spectra of the oversize gangue, an X-ray fluorescence separator (i.e., an XRF separator) is used to pre-sort the oversize gangue (large particles) to obtain lithium gallium-rich concentrate and iron-rich tailings.
[0041] Step 3: Crush the undersize gangue and sorted concentrate to obtain a crushed mixture;
[0042] Step 4: The crushed mixture is magnetically roasted in a tube furnace to obtain the roasted product;
[0043] Step 5: Utilizing the differences in magnetic strength between different minerals, a magnetic separator is used to perform magnetic separation on the roasting products to obtain magnetic tailings and iron-rich magnetic concentrate;
[0044] Step 6: Mix the magnetic separation tailings with the roasting aid and then perform activation roasting, acid leaching and filtration in sequence to obtain leaching residue and lithium gallium leaching solution;
[0045] Step 7: Separate and purify the lithium gallium leaching solution to obtain metallic lithium and metallic gallium, thus completing the treatment of lithium gallium-rich coal gangue.
[0046] Compared with the prior art, the processing method for lithium gallium-rich coal gangue provided by the present invention can achieve efficient utilization of coal gangue and has the characteristics of simple process, wide adaptability, high practicality and low cost.
[0047] Specifically, on the one hand, pre-sorting of the larger-sized oversize gangue removes a portion of the iron-rich tailings, enabling pre-enrichment of lithium and gallium and reducing the processing volume in subsequent processes. On the other hand, magnetization roasting transforms weakly magnetic pyrite into strongly magnetic pyrrhotite, further separating iron-rich magnetic concentrate and reducing the adverse effects of iron in subsequent leaching. Furthermore, activation roasting of the magnetic tailings effectively improves their leaching activity and efficiency. Finally, acid leaching is used to extract lithium and gallium from the magnetic tailings; this simple process effectively improves extraction efficiency, ensuring the efficient and high-value utilization of coal gangue.
[0048] In order to further utilize the tailings obtained, the iron-rich sorted tailings obtained in step 2 and the iron-rich magnetic concentrate obtained in step 5 are used as raw materials for ironmaking.
[0049] In order to further utilize the obtained leaching residue, the leaching residue obtained in step 6 above is mainly composed of SiO2, which can be used as a raw material for the preparation of water glass.
[0050] To ensure sufficient subsequent roasting and leaching, step 3 above includes the following steps:
[0051] Step 31: Use a crusher (e.g., a roller crusher) to crush the undersize gangue and the sorting concentrate to obtain crushed particles with a particle size of less than 0.5 mm.
[0052] Step 32: Grind and dissociate the particles after primary crushing using a grinding mill (e.g., a rod mill) to obtain a crushed mixture.
[0053] Using the above method to crush and grind undersize gangue and sorted concentrate can ensure the full dissociation of undersize gangue and sorted concentrate, promote full reaction during subsequent roasting and leaching, improve roasting efficiency, sorting effect and leaching efficiency, and further improve the resource utilization rate of coal gangue.
[0054] It should be noted that after crushing and grinding, the proportion of the crushed mixture with a particle size range of -0.074mm is over 90%.
[0055] It is worth noting that by controlling the roasting conditions, the weakly magnetic pyrite remaining in the crushed mixture can be transformed into strongly magnetic pyrrhotite. For example, in step 4 above, the magnetic roasting temperature is 450-550℃, the magnetic roasting time is 15-45 min, and the magnetic roasting atmosphere is air or nitrogen.
[0056] In order to achieve sufficient magnetic separation of the calcined products, for example, in step 5 above, the magnetic separation intensity is 200 to 400 mT.
[0057] Considering that the activation calcination conditions will affect the activation efficiency and activation effect, for example, in step 6 above, the activation calcination temperature is 600-800℃ and the activation calcination time is 1-2h.
[0058] To ensure the effectiveness of activation roasting, for example, in step 6 above, the roasting aid includes one or two of NaCl, CaCl2, Na2CO3, CaO, CaF2, and NH4Cl in any proportion, and the mass ratio of the roasting aid to the magnetic separation tailings is 0.5 to 1:1.
[0059] To ensure the full leaching of lithium and gallium, in step 6 above, nitric acid, hydrochloric acid, sulfuric acid, citric acid, or oxalic acid are used as the acid leaching solution. The concentration of the acid leaching solution is 2-5 mol / L, the liquid-to-solid ratio is 1:5-10, the leaching time is 1-3 hours, and the leaching temperature is 60-80℃.
[0060] For example, the above-described method for processing lithium-gallium-rich coal gangue employs a processing system with the following structure, see [link to relevant documentation]. Figure 2 The system includes a screening unit 1 (e.g., a grading screen), a pre-sorting unit 2 (e.g., an X-ray fluorescence separator), a crushing unit (including a crusher 3 and a grinder 4 connected in sequence), a magnetic roasting unit 5 (e.g., a tube furnace), a magnetic separation unit 6 (e.g., a magnetic separator), an activation roasting unit 7 (e.g., a tube furnace), an acid leaching unit 8 (e.g., an acid leaching tank), and a filtration unit. The oversize outlet of the screening unit 1 is connected to the inlet of the pre-sorting unit 2. The sorted concentrate outlet of the pre-sorting unit 2 and the undersize outlet of the screening unit 1 are both connected to the inlet of the crushing unit. The outlet of the crushing unit is connected to the inlet of the magnetic roasting unit 5. The outlet of the magnetic roasting unit 5 is connected to the inlet of the magnetic separation unit 6. The tailings outlet of the magnetic separation unit 6 is connected to the inlet of the activation roasting unit 7. The outlet of the activation roasting unit 7 is connected to the inlet of the acid leaching unit 8. The leachate outlet of the acid leaching unit 8 is connected to the filtration unit.
[0061] Considering that the magnetic calcination unit 5 will generate a large amount of dust-containing exhaust gas when crushing and mixing the material, the above-mentioned treatment system also includes an exhaust gas treatment unit in order to treat the exhaust gas. Specifically, the exhaust gas treatment unit includes a heat exchanger, a cooler and a dust collector connected in sequence to the exhaust gas outlet of the magnetic calcination unit 5.
[0062] Dust removal is a crucial step in exhaust gas treatment. To improve dust removal effect and efficiency, the dust collector described above, for example, includes a dust removal chamber connected to the exhaust gas outlet of the cooler, and a water spray nozzle, a reciprocating sliding filter 11, and an axial flow fan arranged sequentially in the dust removal chamber along the exhaust gas flow direction. The spray direction of the water spray nozzle is along the exhaust gas direction and towards the reciprocating sliding filter 11, which forms a water film on the reciprocating sliding filter 11. The reciprocating sliding filter 11 reciprocates along the exhaust gas flow direction.
[0063] Regarding the driving method of the reciprocating sliding filter 11, the dust collector also includes a reciprocating drive assembly, a mounting rod 9, and a reciprocating guide rail 10. The reciprocating sliding filter 11 is provided with a mounting sleeve 12, which has a through hole along the axial direction. The cross-sectional shape of the through hole is elongated. One end of the mounting rod 9 is inserted into the through hole, and there is a gap between the mounting rod 9 and the hole wall in the vertical direction. The reciprocating guide rail 10 is located in the dust removal chamber and can rotate in the horizontal direction. The cross-sectional shape of the reciprocating guide rail 10 parallel to the direction of movement of the reciprocating sliding filter 11 is triangular.
[0064] During implementation, the initial position of the reciprocating sliding filter 11 is the lowest point of the reciprocating guide rail 10 (i.e., the end furthest from the spray nozzle, with a height of 0). During the reciprocating motion of the reciprocating sliding filter 11, it gradually moves upwards along the reciprocating guide rail 10. Simultaneously, the end of the mounting sleeve 12 moves upwards within the through hole, accommodating the vertical displacement of the reciprocating sliding filter 11 through the gap between the through hole and the mounting sleeve 12. When the reciprocating sliding filter 11 reaches the highest point of the reciprocating guide rail 10 and continues to move, it suddenly detaches from the reciprocating guide rail 10, falls vertically, and vibrates. This vibration causes the liquid film to immediately detach from the reciprocating sliding filter 11, and the droplets sprayed from the spray nozzle form a new liquid film on the reciprocating sliding filter 11. Simultaneously, the reciprocating guide rail 10 rotates 180°, repeating the above motion process. See [link to relevant documentation]. Figure 3 .
[0065] The processing method of the present invention will be described in detail below with reference to Examples 1 to 3:
[0066] Examples 1-3 describe the treatment of coal gangue in Shuozhou, Shanxi Province. The specific treatment steps are as follows:
[0067] Lithium- and gallium-rich coal gangue is fed into a 30mm classifying screen to separate the raw material into oversize and undersize gangue. The oversize gangue is then fed into an XRF separator, where XRF spectra are obtained using X-rays. The differences in XRF spectra between different oversize gangue are used to separate it into lithium- and gallium-rich concentrate and iron-rich tailings. The undersize gangue, along with the XRF concentrate, is fed into a roller crusher for further crushing. The resulting particles have a diameter of less than 0.5mm. The tailings, used as iron-rich gangue, can be used as raw material for ironmaking. The crushed particles are then fed into a rod mill for further grinding and dissociation to ensure sufficient reaction during subsequent activation roasting and acid leaching. The resulting crushed mixture (particle size range) is then processed. The pyrite with a circumference of -0.074 mm (more than 90%) is placed in a tube furnace for magnetization roasting, which transforms the weakly magnetic pyrite remaining in the crushed mixture into strongly magnetic pyrrhotite. The roasting product is then fed into a magnetic separator for magnetic separation. Utilizing the difference in magnetic strength between different roasting products, they are separated into magnetic tailings and iron-rich magnetic concentrate. The iron-rich magnetic concentrate is used as raw material for ironmaking. The magnetic tailings are mixed with roasting aids and then placed in a tube furnace for activation roasting. The activated roasted magnetic tailings are leached with an acid solution, and finally separated by filtration to obtain lithium-gallium leaching solution and leaching residue. The lithium-gallium leaching solution is further separated and purified to obtain lithium and gallium that meet product requirements, and the leaching residue is used as raw material for preparing water glass.
[0068] The process parameters for each step above are shown in Table 1.
[0069] Table 1. Process parameters for Examples 1-3
[0070]
[0071] The data on the utilization effect of the above treatment method on coal gangue are shown in Table 2.
[0072] Table 2. Data on the utilization effect of coal gangue in Examples 1-3
[0073] Magnetic concentrate % Concentrate grade % Lithium leaching rate % Gallium leaching rate % Example 1 8.34 47.96 97.11 94.67 Example 2 11.19 40.06 90.97 86.61 Example 3 10.87 40.19 93.56 90.43
[0074] As shown in Table 2, the method of this invention for processing lithium-gallium-rich coal gangue can effectively separate approximately 10% of the iron-rich raw material (8.34–11.19%), with grades exceeding 40% (40.06–47.96%). After further processing, it can be used as raw material for iron smelting. Magnetic separation removes the iron-rich gangue from the original sample, significantly reducing the iron content in the subsequent leachate, which is highly beneficial for the subsequent separation and purification of gallium. The magnetic separation tailings, after activation, undergo leaching, achieving high leaching efficiencies. The lithium leaching rate is above 90% (90.97–97.11%), and the gallium leaching rate is above 86% (86.61–94.67%), effectively recovering and utilizing the lithium and gallium elements from the coal gangue.
[0075] right Figure 4 It can be seen that after magnetization roasting of coal gangue, the weakly magnetic pyrite in the original sample is transformed into strongly magnetic pyrrhotite, and magnetic separation can effectively separate the iron-rich gangue from the rest. However, due to the short magnetization roasting time, the kaolinite structure in the coal gangue cannot be completely destroyed, and the lithium and gallium elements in the gangue cannot be effectively leached. Therefore, a secondary activation roasting is required to completely destroy the kaolinite structure in the coal gangue and effectively realize the recovery and utilization of lithium and gallium elements in the coal gangue.
[0076] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for processing lithium-gallium-rich coal gangue, characterized in that, Includes the following steps: Step 1: Screen the coal gangue raw material to obtain oversize gangue and undersize gangue; Step 2: Pre-sort the gangue on the screen to obtain lithium-gallium-rich concentrate and iron-rich tailings; Step 3: Crush the undersize gangue and sorted concentrate to obtain a crushed mixture; Step 4: Magnetic roasting of the crushed mixture to obtain the roasted product; Step 5: Perform magnetic separation on the roasting products to obtain magnetic tailings and iron-rich magnetic concentrate; Step 6: Mix the magnetic separation tailings with the roasting aid and then perform activation roasting, acid leaching and filtration in sequence to obtain leaching residue and lithium gallium leaching solution; Step 7: Separate and purify the lithium gallium leaching solution to obtain metallic lithium and metallic gallium, thus completing the treatment of lithium gallium-rich coal gangue.
2. The method for processing lithium-gallium-rich coal gangue according to claim 1, characterized in that, Step 3 includes the following steps: Step 31: Use a crusher to crush the undersize gangue and the sorted concentrate to obtain crushed particles; Step 32: Grind and dissociate the particles after primary crushing using a grinding mill to obtain a crushed mixture.
3. The method for processing lithium-gallium-rich coal gangue according to claim 2, characterized in that, In step 31, the particle size of the crushed particles is less than 0.5 mm.
4. The method for processing lithium-gallium-rich coal gangue according to claim 2, characterized in that, In the crushed mixture, particles with a size range of -0.074 mm account for more than 90%.
5. The method for processing lithium-gallium-rich coal gangue according to claim 1, characterized in that, In step 4, the magnetic calcination temperature is 450–550°C, the magnetic calcination time is 15–45 min, and the magnetic calcination atmosphere is air or nitrogen.
6. The method for processing lithium-gallium-rich coal gangue according to claim 1, characterized in that, In step 5, the magnetic sorting intensity is 200-400 mT.
7. The method for processing lithium-gallium-rich coal gangue according to claim 1, characterized in that, In step 6, the activation calcination temperature is 600-800℃, and the activation calcination time is 1-2 hours.
8. The method for processing lithium-gallium-rich coal gangue according to claim 1, characterized in that, In step 6, the roasting aid includes one or two of NaCl, CaCl2, Na2CO3, CaO, CaF2, and NH4Cl in any proportion, and the mass ratio of the roasting aid to the magnetic separation tailings is 0.5 to 1:
1.
9. The method for processing lithium-gallium-rich coal gangue according to claim 1, characterized in that, In step 6, nitric acid, hydrochloric acid, sulfuric acid, citric acid or oxalic acid are used as the acid leaching solution. The concentration of the acid leaching solution is 2-5 mol / L, the liquid-to-solid ratio is 1:5-10, the leaching time is 1-3 hours, and the leaching temperature is 60-80℃.
10. The method for processing lithium-gallium-rich coal gangue according to claim 1, characterized in that, The iron-rich tailings obtained in step 2 and the iron-rich magnetic concentrate obtained in step 5 are used as raw materials for ironmaking. And / or, the leaching residue obtained in step 6 is used as a raw material for the preparation of water glass.