Rare earth tailing activated coal gangue, preparation method and application thereof

Abstract

The application provides a rare earth tailing activated coal gangue, a preparation method and application thereof, and relates to the technical field of coal-based solid waste treatment.The application provides a preparation method of the rare earth tailing activated coal gangue, which comprises the following steps: mixing coal gangue powder and rare earth tailing powder, and then carrying out roasting activation to obtain the rare earth tailing activated coal gangue; the rare earth tailing powder contains fluorides and chlorides; the temperature of the roasting activation is less than or equal to 850 DEG C; and air is introduced during the roasting activation process.The fluorides and chlorides in the rare earth tailing and the rare earth elements are utilized, the activation energy is greatly reduced, the energy consumption is reduced, the fixed carbon of the coal gangue is reused, a large amount of heat energy is provided by combustion, and a gas-cracking stable silicate and aluminate mineral phase structure is generated; the rare earth tailing is extracted in stages, and no hazardous waste is generated.Further, the mineral phase of the rare earth tailing is highly similar to the mineral phase of the coal gangue, and after catalytic activation, the taste of the final product is not affected, and high-grade minerals can be obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal-based solid waste treatment, and particularly relates to rare earth tailing activated coal gangue and a preparation method and application thereof. BACKGROUND

[0002] Coal gangue is a byproduct in the process of coal mining and washing, and mainly contains silicate and a small amount of carbon. Large amount of coal gangue is prone to cause problems such as spontaneous combustion, dust emission and soil acidification. Activation of coal gangue is helpful to extract carbon, nepheline, kaolinite, illite and montmorillonite in coal gangue, and realize resource utilization of coal gangue. Existing activation methods mainly include alkali leaching activation and high temperature and high pressure activation, but have problems such as high energy consumption and generation of new waste liquid. Therefore, it is urgent to provide an activation method of coal gangue with low energy consumption and less waste liquid. SUMMARY

[0003] Therefore, the present application provides a rare earth tailing activated coal gangue and a preparation method and application thereof. The preparation method provided by the present application has low energy consumption for activation of coal gangue and does not generate new waste liquid.

[0004] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions.

[0005] The present application provides a preparation method of a rare earth tailing activated coal gangue, comprising the following steps:

[0006] Mixing coal gangue powder and rare earth tailing powder to obtain a precursor raw material; the rare earth tailing powder contains fluoride and chloride;

[0007] Carrying out roasting activation on the precursor raw material to obtain a rare earth tailing activated coal gangue; the temperature of the roasting activation is ≤850℃, and air is introduced during the roasting activation.

[0008] Preferably, the particle size of the coal gangue powder and the rare earth tailing powder is independently 38-150 μm.

[0009] Preferably, the mass ratio of the coal gangue powder and the rare earth tailing powder is 100:1-3.

[0010] Preferably, the precursor raw material is first laid before roasting activation, and the thickness of the laying is 3-8 cm.

[0011] Preferably, the roasting activation includes one-stage roasting activation, two-stage roasting activation or three-stage roasting activation.

[0012] Preferably, the first roasting activation comprises: heating at a rate of 20-50℃ / min to 500-550℃, heating at a rate of 5-15℃ / min to 750-850℃ and holding for 30-60min; or, heating at a rate of 20-50℃ / min to 500-550℃, heating at a rate of 10-20℃ / min to 600-700℃, heating at a rate of 5-15℃ / min to 750-850℃ and holding for 30-60min.

[0013] The second roasting activation comprises: heating at a rate of 20-50℃ / min to 500-550℃ and holding for 3-5min, heating at a rate of 5-15℃ / min to 750-850℃ and holding for 30-60min; or, heating at a rate of 20-50℃ / min to 500-550℃ and holding for 3-5min, heating at a rate of 10-20℃ / min to 600-700℃, heating at a rate of 5-15℃ / min to 750-850℃ and holding for 30-60min.

[0014] The third roasting activation comprises: heating at a rate of 20-50℃ / min to 500-550℃ and holding for 3-5min, heating at a rate of 10-20℃ / min to 600-700℃ and holding for 5-15min, heating at a rate of 5-15℃ / min to 750-850℃ and holding for 30-60min.

[0015] The application also provides the rare earth tailing activated coal gangue prepared by the preparation method.

[0016] The application also provides the application of the rare earth tailing activated coal gangue in separating one or more of carbon, nepheline, kaolinite, illite, montmorillonite, iron ore and valuable elements.

[0017] Preferably, the valuable elements comprise one or more of Si, Fe, Al and Ca.

[0018] Preferably, the separation comprises physical separation and / or chemical separation.

[0019] The physical separation comprises one or more of magnetic separation, screening, cyclone and chute.

[0020] The chemical separation comprises one or more of acid dissolution, alkali dissolution and precipitation.

[0021] The raw materials, rare earth tailings and coal gangue used in the application both belong to solid waste, the mineral phase of the two has high similarity, and both have porous structure, which provides the possibility for the synergistic effect of various components to generate activation reaction. The rare earth tailings contain a large amount of fluorides and chlorides, which can significantly improve the chemical activity of the stable mineral phase in the coal gangue, and provide support for the subsequent efficient extraction of carbon, nepheline, kaolinite, illite, montmorillonite and other valuable elements such as Si, Fe, Al and Ca in the coal gangue; the application can reduce the activation temperature of the coal gangue to below 850 DEG C by using the rare earth tailings to activate the coal gangue, and the activation temperature of the coal gangue is low, so the energy consumption is low; the rare earth elements such as cerium elements in the rare earth tailings continuously release and store oxygen elements in the activation process, further catalyze the activation reaction, and further reduce the activation energy. The application greatly reduces the activation energy of the coal gangue by using fluorides, chlorides and rare earth elements in the rare earth tailings, reduces the energy consumption, and has the advantage of low energy consumption; the fixed carbon in the coal gangue is reused to provide a large amount of heat energy, and the gas cracking stable silicate mineral phase structure is generated; the Si, Fe, Al, Ca and other elements in the rare earth tailings activated coal gangue can be obtained by extracting in the gradient pH value range, and no hazardous waste is generated. Moreover, the mineral phase of the rare earth tailings has high similarity with the mineral phase of the coal gangue, and after catalytic activation, it will not affect the taste of the final product, which helps to obtain high-grade minerals. The application uses the carbon associated with the coal gangue as part of the energy, reduces the energy required for activation, and greatly reduces the cost. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is the process flow chart of the rare earth tailings activated coal gangue in the application;

[0023] Figure 2 It is the physical picture of the rare earth tailings activated coal gangue in example 1;

[0024] Figure 3 It is the physical picture of the rare earth tailings activated coal gangue in comparative example 1;

[0025] Figure 4 It is the physical picture of the rare earth tailings activated coal gangue in example 2;

[0026] Figure 5 It is the physical picture of the rare earth tailings activated coal gangue in example 3;

[0027] Figure 6 It is the physical picture of the rare earth tailings activated coal gangue in example 4;

[0028] Figure 7 It is the mineral phase dissociation schematic diagram of the coal gangue activated by the rare earth tailings in example 3;

[0029] Figure 8 It is the process mineralogy analysis diagram of the coal gangue;

[0030] Figure 9 Figure 1 is a process mineralogy analysis chart of the rare earth tailings. DETAILED DESCRIPTION

[0031] The present application provides a preparation method of rare earth tailings activated coal gangue, comprising the following steps:

[0032] The coal gangue powder and the rare earth tailings powder are mixed to obtain a precursor raw material; the rare earth tailings powder contains fluorides and chlorides;

[0033] The precursor raw material is calcined and activated to obtain the rare earth tailings activated coal gangue; the temperature of the calcination and activation is ≤850℃, and air is introduced during the calcination and activation process.

[0034] Unless otherwise specified, the materials and equipment used in the present application are commercially available in the art.

[0035] The present application mixes the coal gangue powder and the rare earth tailings powder to obtain a precursor raw material; the rare earth tailings powder contains fluorides and chlorides.

[0036] In the present application, the coal gangue powder is obtained by crushing, grinding and sieving the coal gangue. In the present application, the mesh size of the sieve is preferably 100 mesh; the sieve preferably includes a vibrating sieve. In the present application, the particle size of the coal gangue powder is preferably 38-150 μm. The present application uses the associated carbon in the coal gangue as part of the energy, reducing the energy required for activation and significantly reducing the cost.

[0037] In the present application, the rare earth tailings powder is obtained by crushing, grinding and sieving the rare earth tailings. In the present application, the mesh size of the sieve is preferably 100 mesh; the sieve preferably includes a vibrating sieve. In the present application, the particle size of the rare earth tailings powder is preferably 38-150 μm. The rare earth tailings contain a large amount of fluorides and chlorides, which can significantly improve the chemical activity of the stable mineral phases in the coal gangue, providing support for the subsequent efficient extraction of carbon, nepheline, kaolinite, illite, montmorillonite, etc. in the coal gangue, as well as valuable elements such as Si, Fe, Al, Ca, etc. The present application uses rare earth tailings to activate coal gangue, which can reduce the activation temperature of the coal gangue to below 850℃, and the activation temperature of the coal gangue is low, which reduces the energy consumption. The rare earth elements such as cerium elements in the rare earth tailings continuously release and store oxygen elements during the activation process, further catalyzing the activation reaction, and further reducing the activation energy. Moreover, the mineral phases of the rare earth tailings and the coal gangue have high similarity, and after catalytic activation, they do not affect the quality of the final product, which helps to obtain high-grade minerals.

[0038] The present application can increase the total surface area, reduce particle agglomeration, and make the coal gangue and rare earth activator (rare earth tailings) have sufficient reaction area, so that the subsequent roasting reaction time can be significantly reduced, and the subsequent physical separation and chemical purification are also beneficial.

[0039] In the present application, the mass ratio of the coal gangue powder and the rare earth tailings powder is preferably 100:1-3, and can be specifically 100:1, 100:1.5, 100:2, 100:2.5 or 100:3. The proportion of bastnaesite and parisite in the rare earth tailings is ≥7%, and cerium element has good oxygen storage and release capacity, and also achieves catalytic effect; fluorine element has strong oxidizing property and electronegativity, and is easy to chemically react with silicon element, so that the stable chemical structure of silicate and silico-aluminate is destroyed to achieve dissociation effect. In the present application, the mass ratio of the coal gangue powder and the rare earth tailings powder is controlled within the above range, and the active elements (including cerium, lanthanum and neodymium) in the rare earth tailings can provide sufficient reaction active sites, and fluorine element opens the mineral phase structure of the coal gangue to provide more reaction conditions, so that the stable silicate and silico-aluminate minerals in the coal gangue are finally dissociated and activated, and the coal gangue mineral phase not only dissociates but also changes in phase, which lays a foundation for subsequent separation.

[0040] After obtaining the precursor raw material, the present application roasts and activates the precursor raw material to obtain rare earth tailings activated coal gangue; the roasting and activation temperature is ≤850℃, and air is introduced during the roasting and activation process.

[0041] In the present application, the precursor raw material is preferably first layered before roasting and activation; the thickness of the layering is preferably 3-8cm, and can be specifically 3cm, 4cm, 5cm, 6cm, 7cm or 8cm.

[0042] In the present application, the roasting and activation preferably includes one-stage roasting and activation, two-stage roasting and activation or three-stage roasting and activation.

[0043] In the present application, the first-stage calcination activation preferably comprises: heating to 500-550℃ (which can be specifically 500℃, 510℃, 520℃, 530℃, 540℃ or 550℃) at a rate of 20-50℃ / min (which can be specifically 20℃ / min, 25℃ / min, 30℃ / min, 35℃ / min, 40℃ / min, 45℃ / min or 50℃ / min), heating to 750-850℃ (which can be specifically 750℃, 760℃, 770℃, 780℃, 790℃, 800℃, 810℃, 820℃, 830℃, 840℃ or 850℃) at a rate of 5-15℃ / min (which can be specifically 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min or 15℃ / min) and then holding for 30-60min (which can be specifically 30min, 35min, 40min, 45min, 50min, 55min or 60min).

[0044] In the present application, the first-stage calcination activation preferably comprises: heating to 500-550℃ (which can be specifically 500℃, 510℃, 520℃, 530℃, 540℃ or 550℃) at a rate of 20-50℃ / min (which can be specifically 20℃ / min, 25℃ / min, 30℃ / min, 35℃ / min, 40℃ / min, 45℃ / min or 50℃ / min), heating to 600-700℃ (which can be specifically 600℃, 610℃, 620℃, 630℃, 640℃, 650℃, 660℃, 670℃, 680℃, 690℃ or 7000℃) at a rate of 10-20℃ / min (which is referred to as the third heating rate), heating to 750-850℃ (which can be specifically 750℃, 760℃, 770℃, 780℃, 790℃, 800℃, 810℃, 820℃, 830℃, 840℃ or 850℃) at a rate of 5-15℃ / min (which can be specifically 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min or 15℃ / min) and then holding for 30-60min (which can be specifically 30min, 35min, 40min, 45min, 50min, 55min or 60min).

[0045] In the present application, the two-stage calcination activation preferably comprises: heating to 500-550°C (which can be specifically 500°C, 510°C, 520°C, 530°C, 540°C or 550°C) at a rate of 20-50°C / min (which can be specifically 20°C / min, 25°C / min, 30°C / min, 35°C / min, 40°C / min, 45°C / min or 50°C / min) and then holding for 3-5 min (which can be specifically 3 min, 3.5 min, 4 min, 4.5 min or 5 min), and then heating to 750-850°C (which can be specifically 750°C, 760°C, 770°C, 780°C, 790°C, 800°C, 810°C, 820°C, 830°C, 840°C or 850°C) at a rate of 5-15°C / min (which can be specifically 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, 11°C / min, 12°C / min, 13°C / min, 14°C / min or 15°C / min) and then holding for 30-60 min (which can be specifically 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 60 min).

[0046] In the present application, the two-stage calcination activation preferably further comprises: heating to 500-550°C (may be specifically 500°C, 510°C, 520°C, 530°C, 540°C or 550°C) at a rate of 20-50°C / min (may be specifically 20°C / min, 25°C / min, 30°C / min, 35°C / min, 40°C / min, 45°C / min or 50°C / min), holding for 3-5 min (may be specifically 3 min, 3.5 min, 4 min, 4.5 min or 5 min), heating to 600-700°C (may be specifically 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C, 680°C, 690°C or 7000°C) at a rate of 10-20°C / min (may be specifically 10°C / min, 11°C / min, 12°C / min, 13°C / min, 14°C / min, 15°C / min, 16°C / min, 17°C / min, 18°C / min, 19°C / min or 20°C / min), and holding for 30-60 min (may be specifically 30 min, 35 min, 40 min, 45 min, 50 min, 55 min or 60 min) after heating to 750-850°C (may be specifically 750°C, 760°C, 770°C, 780°C, 790°C, 800°C, 810°C, 820°C, 830°C, 840°C or 850°C) at a rate of 5-15°C / min (may be specifically 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, 11°C / min, 12°C / min, 13°C / min, 14°C / min or 15°C / min). In the present application, the difference between the two-stage calcination and the one-stage calcination is that the two-stage calcination needs to be held for 3-5 min after heating to 500-550°C.

[0047] In the present application, the three-stage roasting activation preferably comprises: heating to 500-550℃ (which can be specifically 500℃, 510℃, 520℃, 530℃, 540℃ or 550℃) at a rate of 20-50℃ / min (which can be specifically 20℃ / min, 25℃ / min, 30℃ / min, 35℃ / min, 40℃ / min, 45℃ / min or 50℃ / min) and then holding for 3-5min (which can be specifically 3min, 3.5min, 4min, 4.5min or 5min), heating to 600-700℃ (which can be specifically 600℃, 610℃, 620℃, 630℃, 640℃, 650℃, 660℃, 670℃, 680℃, 690℃ or 7000℃) at a rate of 10-20℃ / min (which can be specifically 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min, 15℃ / min, 16℃ / min, 17℃ / min, 18℃ / min, 19℃ / min or 20℃ / min) and then holding for 5-15min (which can be specifically 5min, 6min, 7min, 8min, 9min, 10min, 11min, 12min, 13min, 14min or 15min), heating to 750-850℃ (which can be specifically 750℃, 760℃, 770℃, 780℃, 790℃, 800℃, 810℃, 820℃, 830℃, 840℃ or 850℃) at a rate of 5-15℃ / min (which can be specifically 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min or 15℃ / min) and then holding for 30-60min (which can be specifically 30min, 35min, 40min, 45min, 50min, 55min or 60min). In the present application, the difference between the three-stage roasting and the two-stage roasting lies in that the temperature is held for 5-15min after heating to 600-700℃.

[0048] In the present application, air is introduced during the roasting activation; the roasting activation is preferably carried out in a trolley furnace. Introducing oxygen during the roasting activation will cause the fixed carbon in the coal gangue to burn violently, the local temperature to rise, sintering and coking to occur, and the fluorides in the rare earth tailings to decompose and flow away rapidly, which cannot achieve the purpose of activating and dissociating the mineral phase. In the present application, air is introduced, which can achieve good roasting activation and retain the fluoride components in the rare earth tailings.

[0049] In the low-temperature stage (first temperature rising and low-temperature calcination activation), the equipment and the material are rapidly heated, and short holding time makes the internal and external temperatures of the material consistent, so that the carbon particles in the material are ignited and heat is provided; in the high-temperature stage (second temperature rising and high-temperature calcination activation), the heat generated by carbon combustion increases the temperature, and the heat provided by the equipment is greatly reduced, which protects the equipment, prolongs the service life of the equipment and reduces energy consumption; carbon combustion produces carbon dioxide and sulfur dioxide gas, which can be introduced into the subsequent chemical separation process to produce corresponding alkali pool absorption (calcium carbonate and calcium sulfate can be obtained), and no pollution to the environment is caused, energy saving and environmental protection are achieved.

[0050] The raw materials, rare earth tailings and coal gangue used in the present application both belong to solid waste, and the mineral phases of the two have high similarity and both have porous structures, which provide the possibility for the activation reaction of the synergistic effect of various components. The present application utilizes the fluorides, chlorides and rare earth elements in the rare earth tailings to greatly reduce the activation energy of the coal gangue and reduce energy consumption, and has the advantage of low energy consumption; the fixed carbon in the coal gangue is burned to provide a large amount of heat energy, and a gas-cracked stable silicate mineral phase structure is produced; step-by-step extraction, no hazardous waste is produced.

[0051] The present application also provides the rare earth tailings activated coal gangue obtained by the method of the above technical solution.

[0052] The present application also provides the application of the rare earth tailings activated coal gangue of the above technical solution in separating one or more of carbon, nepheline, kaolinite, illite, montmorillonite, iron ore and valuable elements.

[0053] In the present application, the valuable elements preferably include one or more of Si, Fe, Al and Ca.

[0054] In the present application, the separation preferably includes physical separation and / or chemical separation.

[0055] In the present application, the physical separation preferably includes one or more of magnetic separation, screening, cyclone and chute.

[0056] In the present application, the magnetic field strength of the magnetic separation is preferably 120-240 kA / m, which can be specifically 120 kA / m, 140 kA / m, 160 kA / m, 180 kA / m, 200 kA / m, 220 kA / m or 240 kA / m. In the present application, the screening preferably can obtain iron ore.

[0057] In the present application, the screen size of the screening is preferably 100-400 meshes, which can be specifically 100 meshes, 200 meshes, 300 meshes or 400 meshes. The present application adopts 100-400 mesh standard screens for screening, which can grade the raw materials and accelerate the process of subsequent chemical separation.

[0058] In the present application, the mass concentration of the feed ore of the cyclone is preferably 30-40%, and can be specifically 30%, 32%, 35%, 38% or 40%.

[0059] In the present application, the mass concentration of the feed ore of the chute is preferably 40-60%, and can be specifically 40%, 45%, 50%, 55% or 60%.

[0060] In the present application, one or more of nepheline, kaolinite, illite and montmorillonite can be obtained through the cyclone and / or the chute.

[0061] In the present application, the chemical separation preferably comprises one or more of acid dissolution, alkali dissolution and precipitation.

[0062] In the present application, the acid used in the acid dissolution preferably comprises one or more of hydrochloric acid, nitric acid and sulfuric acid; the present application is not particularly limited in the conditions for the acid dissolution, and the acid dissolution conditions well known to those skilled in the art can be adopted. In the present application, the purpose of the acid dissolution is to convert the metal substances in the raw material into ionic form and exist in the water system.

[0063] In the present application, the alkali used in the alkali dissolution preferably comprises alkali metal hydroxide, and can be specifically sodium hydroxide and / or potassium hydroxide; the present application is not particularly limited in the conditions for the alkali dissolution, and the alkali dissolution conditions well known to those skilled in the art can be adopted. In the present application, the purpose of the alkali dissolution is to make the alkali-soluble substances (for example, aluminum) in the raw material exist in the water system through alkali dissolution.

[0064] In the present application, the precipitation is preferably carried out by adjusting the pH value, and the valuable element precipitate obtained by the precipitation of the present application preferably comprises one or more of metal hydroxide, orthosilicic acid and silica gel, and the metal hydroxide can specifically comprise one or more of iron hydroxide, aluminum hydroxide and calcium hydroxide. The present application does not have special limitations on the conditions for the precipitation by adjusting the pH value, which can be determined according to the precipitation kinetics of each ion. The present application uses the precipitation kinetics of each ion to prepare the valuable element precipitate by precipitating at a step difference in the pH value, for example, the pH value for the precipitation of iron element is preferably 2.7-3.7, and can be specifically 2.7, 3, 3.2, 3.4, 3.5 or 3.7, the iron element can be precipitated at pH≥2.7, and the precipitation is complete at pH=3.7; the pH value for the precipitation of aluminum element is preferably 5.5-8, and can be specifically 5.5, 6, 6.5, 7, 7.5 or 8, the aluminum element starts to precipitate at pH=5.5, the precipitation is complete at pH=8, and the aluminum element starts to dissolve in the alkaline water system again at pH=8.5; the pH value for the precipitation of calcium element is preferably 12.4-13.4, and can be specifically 12.4, 12.6, 12.8, 13, 13.2 or 13.4, the calcium element starts to precipitate at pH=12.4, and the precipitation is complete at pH=13.4; the pH value for the precipitation of silicon element is preferably 6-7, and can be specifically 6, 6.2, 6.4, 6.6, 6.8 or 7, the silicon element exists in the form of silicic acid, and precipitates in the form of orthosilicic acid or silica gel at pH=6-7. The present application uses the different pH value ranges for the precipitation of Si, Fe, Al and Ca elements in the aqueous phase, combines ksp and HSC analysis, calculates the precipitation pH value, and performs step extraction at different pH values, so that the corresponding products can be obtained.

[0065] After the precipitation, the present application preferably further comprises solid-liquid separation of the precipitation system, washing and drying the obtained solid component to obtain the valuable element precipitate.

[0066] In order to further illustrate the present application, the rare earth tailings activated coal gangue provided by the present application, the preparation method and application thereof are described in detail below, but they should not be understood as limitations on the protection scope of the present application.

[0067] In the following examples and comparative examples, the coal gangue produced by a certain coal mine in Ordos and the rare earth tailings produced by a certain rare earth mine in Baotou are used as raw materials to study the mineral structure and distribution, element composition and other information, and the mineral composition of the rare earth tailings and the coal gangue is shown in Tables 1-2.

[0068] Table 1 Composition of rare earth tailings and coal gangue (wt%)

[0069]

[0070] Table 2 Composition of rare earth tailings and coal gangue (wt%)

[0071]

[0072] Example 1

[0073] According to the process flow chart shown in FIG. 1, coal gangue is activated. Figure 1

[0074] S1: The coal gangue and the rare earth tailings are respectively crushed, ground, and passed through a 100-mesh vibrating screen, to obtain coal gangue powder and rare earth tailings powder, both having a particle size of 38-150 μm.

[0075] S2: Then the coal gangue powder and the rare earth tailings powder are mixed uniformly in a mass ratio of 100:1, to obtain a precursor raw material.

[0076] S3: The precursor raw material is laid flat on a car bottom furnace for one-stage roasting and activation, to obtain rare earth tailings activated coal gangue. In the one-stage roasting and activation, the temperature is raised to 550°C at a rate of 30°C / min, and then raised to 830°C at a rate of 10°C / min, and held for 30 min; the thickness of the laid precursor raw material is 3 cm; and air is introduced during the roasting and activation.

[0077] S4: The rare earth tailings activated coal gangue is subjected to physical and chemical separation and purification, to obtain high-grade minerals and products.

[0078] A physical picture of the rare earth tailings activated coal gangue prepared in this example is shown in FIG. 2. Figure 2 As can be seen, the coal gangue material is completely activated, but the yield is low.

[0079] Comparative Example 1

[0080] The difference from Example 1 is that air is not introduced during the one-stage roasting and activation.

[0081] A physical picture of the rare earth tailings activated coal gangue prepared in this comparative example is shown in FIG. 3. Figure 3 As can be seen, the coal gangue is not completely activated, and there is some unactivated coal gangue at the bottom and center.

[0082] Example 2

[0083] The difference from Example 1 is that the mass ratio of the coal gangue powder to the rare earth tailings powder is 500:1.

[0084] A physical picture of the rare earth tailings activated coal gangue prepared in this example is shown in FIG. 4. Figure 4 As can be seen, with a reduced proportion of rare earth tailings, there is a clear division after activation, and some rare earths are not activated.

[0085] Example 3

[0086] ​The difference from example 1 is only that two-stage roasting activation is adopted: after being heated to 500 DEG C at a rate of 30 DEG C / min and being kept for 10 min, being heated to 650 DEG C at a rate of 20 DEG C / min, and being heated to 830 DEG C at a rate of 10 DEG C / min and being kept for 30 min.

[0087] The rare earth tailings activated coal gangue prepared in the example is shown in the physical picture Figure 5 It can be seen that the coal gangue material is completely activated.

[0088] Example 4

[0089] The difference from example 1 is only that three-stage roasting activation is adopted: after being heated to 500 DEG C at a rate of 30 DEG C / min and being kept for 10 min, being heated to 650 DEG C at a rate of 20 DEG C / min and being kept for 10 min, and being heated to 830 DEG C at a rate of 10 DEG C / min and being kept for 30 min.

[0090] The rare earth tailings activated coal gangue prepared in the example is shown in the physical picture Figure 6 It can be seen that the coal gangue material is completely activated.

[0091] It can be seen from examples 3-4 that the segmented roasting activation is beneficial to the efficient heat transfer to the center of the material, so that the material is fully activated, but there is no obvious difference between the three-stage roasting activation and the two-stage roasting activation on the material activation, and the two-stage roasting can better utilize the heat and reduce the energy loss.

[0092] Under the condition of field emission scanning electron microscope, the mineral dissociation diagram of the coal gangue activated by the rare earth tailings in example 3 is analyzed by using process mineralogy software BPMA, and is shown in Figure 7 , Figure 7 The left is the mineral state before activation, and the right is the mineral state after activation, and it can be seen that the original inclusion of the coal gangue is dissociated, and each single mineral (without inclusion) is generated, which indicates that the coal gangue activated by the method provided by the application is dissociated into smaller single minerals, has a good activation effect, and creates conditions for subsequent separation.

[0093] Under the condition of field emission scanning electron microscope, the mineral composition and mineral phase structure of the coal gangue are analyzed by using process mineralogy software, and the results are shown in Figure 8 It can be seen that the coal gangue has inclusion, and it is difficult to directly process, and needs to be dissociated and activated.

[0094] Under the condition of field emission scanning electron microscope, the mineral phase structure and mineral composition of the rare earth tailings are analyzed by using process mineralogy software, and the results are shown in Figure 9 It can be seen that the rare earth tailings have highly similar mineral composition and structure with the coal gangue, and in addition, the rare earth tailings contain a large amount of cerium fluoride and rare earth elements, and can be combined with the coal gangue for processing and activating the coal gangue.

[0095] The above merely describes the preferred embodiments of the present application, and it should be pointed out that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the protection scope of the present application.

Claims

1. A method for preparing rare earth tailings activated coal gangue, comprising the following steps: mixing coal gangue powder and rare earth tailings powder to obtain a precursor raw material; the rare earth tailings powder contains fluoride and chloride; calcining and activating the precursor raw material to obtain rare earth tailings activated coal gangue; the calcining and activating temperature is ≤ 850 ℃, and air is introduced during the calcining and activating process to achieve the dissociation of the coal gangue and lay a foundation for subsequent separation. The particle size of the coal gangue powder and the rare earth tailings powder is independently 38-150 μm. The mass ratio of the coal gangue powder to the rare earth tailings powder is 100: 1-3.

2. The production method according to claim 1, characterized by, The precursor raw material is first layered before calcining and activating, and the thickness of the layering is 3-8 cm.

3. The preparation method according to claim 1, characterized in that, The calcining and activating includes one-stage calcining and activating, two-stage calcining and activating, or three-stage calcining and activating.

4. The production method according to claim 1, characterized by, The one-stage calcining and activating includes: increasing the temperature to 500-550 ℃ at a rate of 20-50 ℃ / min, increasing the temperature to 750-850 ℃ at a rate of 5-15 ℃ / min and maintaining for 30-60 min; or increasing the temperature to 500-550 ℃ at a rate of 20-50 ℃ / min, increasing the temperature to 600-700 ℃ at a rate of 10-20 ℃ / min, increasing the temperature to 750-850 ℃ at a rate of 5-15 ℃ / min and maintaining for 30-60 min.

5. The method of any one of claims 1 to 4, wherein the method further comprises the step of: The two-stage calcining and activating includes: increasing the temperature to 500-550 ℃ at a rate of 20-50 ℃ / min and maintaining for 3-5 min, increasing the temperature to 750-850 ℃ at a rate of 5-15 ℃ / min and maintaining for 30-60 min; or increasing the temperature to 500-550 ℃ at a rate of 20-50 ℃ / min and maintaining for 3-5 min, increasing the temperature to 600-700 ℃ at a rate of 10-20 ℃ / min, increasing the temperature to 750-850 ℃ at a rate of 5-15 ℃ / min and maintaining for 30-60 min.

6. The production method according to claim 5, wherein The three-stage calcining and activating includes: increasing the temperature to 500-550 ℃ at a rate of 20-50 ℃ / min and maintaining for 3-5 min, increasing the temperature to 600-700 ℃ at a rate of 10-20 ℃ / min and maintaining for 5-15 min, increasing the temperature to 750-850 ℃ at a rate of 5-15 ℃ / min and maintaining for 30-60 min. 7.The rare earth tailings activated coal gangue obtained by the method according to any one of claims 1-6. 8.The use of the method according to any one of claims 1-6 in the separation of one or more of carbon, nepheline, kaolinite, illite, montmorillonite, iron ore and valuable elements in the rare earth tailings activated coal gangue. The valuable elements include one or more of Si, Fe, Al and Ca. The separation includes physical separation and / or chemical separation.

9. Use according to claim 8, characterized in that, The physical separation includes one or more of magnetic separation, screening, cyclone and chute.

10. Use according to claim 8 or 9, characterized in that, The chemical separation includes one or more of acid dissolution, alkali dissolution and precipitation. ​ ​

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