A coal gangue-based white wear-resistant medium material modified based on rare earth elements and a preparation method thereof

Abstract

The application provides a coal gangue-based white wear-resistant medium material modified based on rare earth elements and a preparation method thereof, and the material comprises pretreated coal gangue powder, a composite additive, an auxiliary additive and a binder, wherein the mass ratio of the pretreated coal gangue powder, the composite additive and the auxiliary additive is 100:(0.01-20):(0.05-5), the ratio of the adding amount of the binder to the total mass of the pretreated coal gangue powder, the composite additive and the auxiliary additive is (3-60):100, and the composite additive comprises an additive A and an additive B with a mass ratio of 1:(0.5-4). The application uses coal gangue as raw material, solves the problems of environmental pollution and safety hazards caused by coal gangue storage, has simple preparation process and is easy to implement, improves the utilization rate of coal gangue, can be used in the field of ceramic wear-resistant medium and the like, and realizes the collaborative preparation of solid waste resource utilization and high-performance ceramic materials.

Description

Technical Field

[0001] This invention belongs to the field of comprehensive utilization of industrial solid waste, and in particular relates to a white wear-resistant media material based on rare earth element modification of coal gangue and its preparation method. Background Technology

[0002] Coal gangue is a solid waste generated during coal mining, extraction, and washing. my country has a massive accumulation of coal gangue, and its long-term accumulation and discharge pose significant hazards. Open-air stockpiles encroach on large amounts of arable land and forest land; stockpiled coal gangue is prone to collapse and landslides, causing environmental disasters such as soil and water pollution; and the resulting solid dust pollutes the atmosphere. In recent years, coal gangue waste has shown great potential for application in chemical, building materials, metallurgy, and light industries as a recyclable resource, but its utilization volume is limited. Therefore, improving the comprehensive utilization rate of coal gangue, using inexpensive waste raw materials to produce products with economic value, and achieving the goals of turning waste into treasure, energy conservation, and environmental protection, has significant economic and social value.

[0003] The main chemical components of coal gangue are alumina and silicon dioxide, which are also commonly used raw materials for ceramic production. While alumina ceramics, as a grinding media, have wide applications in building and sanitary ceramics, industrial ceramics, refractory materials, and special cements, traditional high-alumina wear-resistant media still face some problems, such as defects like spots, blistering, adhesion, and wind crystal formation during production. The addition of rare earth materials can significantly improve the sintering activity and densification of ceramic materials through mechanisms such as grain refinement and liquid-phase regulation. Through component optimization design, a dual innovative model of solid waste resource utilization and performance enhancement is proposed, providing a new technical path for building a green resource system. Summary of the Invention

[0004] In view of this, the present invention aims to overcome the defects in the prior art and proposes a white wear-resistant media material based on rare earth element modification of coal gangue and its preparation method.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] In a first aspect, the present invention provides a white wear-resistant media material based on rare earth element modification of coal gangue, comprising pretreated coal gangue powder, composite additives, auxiliary additives and binder, wherein the mass ratio of pretreated coal gangue powder, composite additives and auxiliary additives is 100:(0.01~20):(0.05~5), the amount of binder added is in the ratio of the total mass of the three components of pretreated coal gangue powder, composite additives and auxiliary additives to (3~60):100, and the composite additives include additive A and additive B in a mass ratio of 1:(0.5-4).

[0007] Preferably, the auxiliary agent A is a lanthanum / yttrium complex, which is prepared by mixing a lanthanum source compound and a yttrium source compound.

[0008] Preferably, the lanthanum source compound includes, but is not limited to, one or both of lanthanum oxalate and lanthanum zirconate.

[0009] Preferably, the yttrium source compound includes, but is not limited to, one or more of yttrium oxide, yttrium aluminate, yttrium hydroxide, yttrium carbonate, and yttrium fluoride.

[0010] Preferably, the mass ratio of the lanthanum source compound to the yttrium source compound is 1:10 to 10:1.

[0011] Preferably, the additive B includes, but is not limited to, one or more of zircon sol, zircon sand, and zirconium oxide.

[0012] Preferably, the auxiliary additives include, but are not limited to, one or more of magnesium fluoride, spodumene, aluminum fluoride, and boron oxide. These auxiliary additives, acting as fluxes, promote the sintering densification process and lower the firing temperature by lowering the melting point and forming a liquid phase.

[0013] Preferably, the aluminum-silicon ratio in the pretreated coal gangue powder is between 0.5 and 1.8, wherein the total percentage content of calcium oxide and magnesium oxide is not greater than 1 wt%, the percentage content of iron oxide is not greater than 1 wt%, and the total percentage content of potassium and sodium is not greater than 1 wt%.

[0014] Preferably, the preparation method of the pretreated coal gangue powder is as follows: the coal gangue raw material is crushed, dried, magnetically separated, treated and washed with 20% volume concentration hydrochloric acid, and finally the washed coal gangue is placed in a drying oven for drying and high-energy ball milling.

[0015] The crushed coal gangue is dried in a drying oven at 105-120℃ for 2-4 hours; magnetic separation is performed 1-3 times to remove magnetic minerals; hydrochloric acid treatment is carried out at 60-80℃ for 2-4 hours to remove carbonate minerals from the coal gangue, reduce the generation of decomposition gases during subsequent high-temperature treatment, dissolve impurities on the surface of the coal gangue, and activate the surface; finally, the washed coal gangue is placed in a drying oven for further drying.

[0016] Preferably, the particle size of the pretreated coal gangue powder is 3-120µm.

[0017] Preferably, the binder includes, but is not limited to, one or more of the following: water, a 4.35 wt% water glass solution, a 5 wt% aluminum dihydrogen phosphate solution, an 20 wt%-25 wt% aluminum sol, and a 5 wt%-50 wt% silica sol.

[0018] Secondly, the present invention also provides a method for preparing the above-mentioned rare earth element modified coal gangue-based white wear-resistant media material, comprising the following steps:

[0019] Composite additives and auxiliary additives are mixed with pretreated coal gangue powder in one step to obtain a precursor material. A binder is added to the precursor material for pelletizing, aging, and sintering. Finally, the material is cooled to room temperature in the furnace to obtain a white wear-resistant medium material based on rare earth element modification of coal gangue.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) Compared with traditional technologies, this invention uses coal gangue as raw material, which solves the environmental pollution and safety hazards caused by coal gangue stockpiling. The preparation process is simple and easy to implement, which improves the utilization rate of coal gangue and realizes the synergistic preparation of solid waste resource utilization and high-performance ceramic materials.

[0022] (2) The additive A in the rare earth element modified coal gangue-based white wear-resistant media material of the present invention is a lanthanum / yttrium composite. During the high-temperature reaction, it refines the crystal lattice and inhibits abnormal grain growth. During sintering, it generates a liquid phase, accelerating the densification process. Furthermore, during sintering, because lanthanum and yttrium have different affinities for different types and states of coloring ions, their combined use can more comprehensively suppress coloring impurities in the coal gangue raw material. Simultaneously, during the densification process, it reduces porosity, thus improving… By refining the microstructure, light scattering loss can be reduced, achieving a whitening effect and improving the whiteness of the wear-resistant media material. In addition, there is a synergistic effect between additive A and additive B. The liquid phase environment generated by additive A can promote the uniform dispersion of additive B in the coal gangue matrix, making the two more firmly bonded. The high-density matrix created by additive A through grain refinement provides support for fully exerting the reinforcing effect of additive B. The grain refinement strengthening of additive A and the phase transformation toughening of additive B jointly improve the wear resistance of the coal gangue-based white wear-resistant media material. Attached Figure Description

[0023] Figure 1 The image shows the microstructure of the rare earth element-modified coal gangue-based white wear-resistant media material prepared in Example 1.

[0024] Figure 2 The image shows the microstructure of the rare earth element-modified coal gangue-based white wear-resistant media material prepared in Comparative Example 4. Detailed Implementation

[0025] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0026] In this document, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0027] In this document, when values ​​are described as ranges, it should be understood that such disclosure includes disclosure of all possible subranges within that range, as well as the specific numerical values ​​falling within that range, regardless of whether the specific numerical value or specific subrange is explicitly specified.

[0028] In this article, the terms "multiple" or "more than" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0029] In this document, the terms "preferred" and "more preferred" are used only to describe implementation methods or embodiments with better effects, and should be understood as not constituting a limitation on the scope of protection of this invention.

[0030] In this document, terms such as "further" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this invention.

[0031] In this article, the term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0032] In this document, the term "about" means a specified value of + / - 10%, preferably + / - 5%, and more preferably + / - 1%.

[0033] In this article, the terms “include,” “including,” “have,” “contain,” etc., are all open-ended terms, meaning that they include but are not limited to.

[0034] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0035] The present invention will be described in detail below with reference to embodiments.

[0036] Example 1

[0037] A method for preparing a rare earth element-modified coal gangue-based white wear-resistant media material includes the following steps:

[0038] (1) Select coal gangue raw material, crush it, place the crushed coal gangue in a drying oven at 105℃ for 4 hours, use a magnetic separator to perform three magnetic separations to remove magnetic minerals, treat the coal gangue powder after preliminary iron removal with hydrochloric acid with a volume concentration of 20% at 80℃ for 2 hours to remove carbonate minerals in the coal gangue, reduce the generation of decomposition gas during subsequent high-temperature treatment, dissolve impurities on the surface of the coal gangue, activate the surface, and finally place the washed coal gangue in a drying oven for drying.

[0039] (2) After carbon removal treatment, the mass percentage of each component of coal gangue powder is as follows: alumina ≤ 47.3%, silicon dioxide ≤ 52.4%, calcium oxide + magnesium oxide ≤ 0.5%, iron oxide ≤ 1%, potassium + sodium ≤ 1%, and the aluminum-silicon ratio of coal gangue powder is 0.9. After high-energy ball milling, the coal gangue powder is further refined to improve the uniformity of the powder and make its particle size 20µm.

[0040] (3) Lanthanum oxalate and yttrium oxide are mixed at a mass ratio of 1:2 to obtain additive A. Additive A is mixed with zirconium sol at a mass ratio of 1:3 to obtain composite additive. Composite additive and magnesium fluoride are directly mixed with coal gangue powder after high-energy ball milling at a mass ratio of 2:0.5:100 in one step to obtain precursor material. Then, 30% of the total mass of the precursor material is added to neutral water for pelletizing, aging and sintering. Finally, the material is cooled to room temperature with furnace air to obtain coal gangue-based white wear-resistant media material modified by rare earth elements.

[0041] Example 2

[0042] A method for preparing a rare earth element-modified coal gangue-based white wear-resistant media material includes the following steps:

[0043] (1) Select coal gangue raw material, crush it, put the crushed coal gangue in a 120℃ drying oven for 2 hours, use a magnetic separator to perform three magnetic separations to remove magnetic minerals, treat the coal gangue powder after preliminary iron removal with 20% hydrochloric acid at 60℃ for 4 hours to remove carbonate minerals in the coal gangue, reduce the generation of decomposition gas during subsequent high-temperature treatment, dissolve impurities on the surface of the coal gangue, activate the surface, and finally put the washed coal gangue in a drying oven for drying.

[0044] (2) The mass percentage of each component of the coal gangue powder after carbon removal treatment: alumina ≤ 47.3%, silicon dioxide ≤ 52.4%, calcium oxide + magnesium oxide ≤ 0.5%, iron oxide ≤ 1%, potassium + sodium ≤ 1%; Quartz sand was added to adjust the composition, and the aluminum-silicon ratio of the coal gangue powder was adjusted to 0.8. The coal gangue powder with the adjusted aluminum-silicon ratio was further refined by high-energy ball milling to improve the uniformity of the powder and make its particle size 10µm.

[0045] (3) Lanthanum oxalate and yttrium carbonate are mixed at a mass ratio of 10:1 to obtain additive A. Additive A is mixed with zircon sand at a mass ratio of 1:1 to obtain composite additive. The composite additive and aluminum fluoride are directly mixed with coal gangue powder after high-energy ball milling at a mass ratio of 0.01:0.05:100 in one step to obtain precursor material. Then, 60% of the total mass of the precursor material is added to neutral water for pelletizing, aging and sintering. Finally, the mixture is cooled to room temperature with furnace air to obtain coal gangue-based white wear-resistant media material modified by rare earth elements.

[0046] Example 3

[0047] A method for preparing a rare earth element-modified coal gangue-based white wear-resistant media material includes the following steps:

[0048] (1) Select coal gangue raw material, crush it, put the crushed coal gangue in a 110℃ drying oven for 3 hours, use a magnetic separator to perform one magnetic separation to remove magnetic minerals, treat the coal gangue powder after preliminary iron removal with 20% hydrochloric acid at 70℃ for 4 hours to remove carbonate minerals in the coal gangue, reduce the generation of decomposition gas during subsequent high temperature treatment, dissolve impurities on the surface of the coal gangue, activate the surface, and finally put the washed coal gangue in a drying oven for drying.

[0049] (2) The mass percentage of each component of the coal gangue powder after carbon removal treatment: alumina ≤ 47.3%, silicon dioxide ≤ 52.4%, calcium oxide + magnesium oxide ≤ 0.5%, iron oxide ≤ 1%, potassium + sodium ≤ 1%; silicon dioxide was added to adjust the composition, and the aluminum-silicon ratio of the coal gangue powder was adjusted to 0.7. The coal gangue powder with the adjusted aluminum-silicon ratio was further refined by high-energy ball milling to improve the uniformity of the powder and make its particle size 5µm.

[0050] (3) Lanthanum zirconate and yttrium hydroxide are mixed at a mass ratio of 1:10 to obtain additive A. Additive A is mixed with zirconium oxide at a mass ratio of 1:4 to obtain composite additive. Composite additive and boron oxide are directly mixed with coal gangue powder after high-energy ball milling at a mass ratio of 20:5:100 in one step and thoroughly mixed to obtain precursor material. Then, 20% of the total mass of the precursor material is added to aluminum dihydrogen phosphate solution, wherein the concentration of aluminum dihydrogen phosphate solution is 5wt%. Then, pelleting, aging and sintering are carried out. Finally, the mixture is cooled to room temperature with furnace air to obtain coal gangue-based white wear-resistant media material modified by rare earth elements.

[0051] Example 4

[0052] A method for preparing a rare earth element-modified coal gangue-based white wear-resistant media material includes the following steps:

[0053] (1) Select coal gangue raw material, crush it, place the crushed coal gangue in a 100℃ drying oven for 4 hours, use a magnetic separator to perform 3 magnetic separations to remove magnetic minerals, treat the coal gangue powder after preliminary iron removal with 20% hydrochloric acid at 80℃ for 3 hours to remove carbonate minerals in the coal gangue, reduce the generation of decomposition gas during subsequent high-temperature treatment, dissolve impurities on the surface of the coal gangue, activate the surface, and finally place the washed coal gangue in a drying oven for drying.

[0054] (2) The mass percentage of each component of the coal gangue powder after carbon removal treatment: alumina ≤ 47.3%, silicon dioxide ≤ 52.4%, calcium oxide + magnesium oxide ≤ 0.5%, iron oxide ≤ 1%, potassium + sodium ≤ 1%; Alumina was added to adjust the composition, and the aluminum-silicon ratio of the coal gangue powder was adjusted to 1.0. The coal gangue powder with the adjusted aluminum-silicon ratio was further refined by high-energy ball milling to improve the uniformity of the powder and make its particle size 50µm.

[0055] (3) Lanthanum zirconate and yttrium fluoride are mixed at a mass ratio of 3:2 to obtain additive A. Additive A is mixed with zirconium oxide at a mass ratio of 1:0.5 to obtain composite additive. Composite additive and boron oxide are directly mixed with coal gangue powder after high-energy ball milling at a mass ratio of 4:1:100 in one step and thoroughly mixed to obtain precursor material. Then, 45% of the total mass of precursor material is added to water glass solution, wherein the concentration of water glass solution is 4.35wt%. Then, pelletizing, aging and sintering are carried out. Finally, the mixture is cooled to room temperature with furnace air to obtain coal gangue-based white wear-resistant media material modified by rare earth elements.

[0056] Comparative Example 1

[0057] A method for preparing a white wear-resistant media material based on rare earth element modification of coal gangue, which differs from Example 1 in that only additive A is added, and additive B is not added.

[0058] Comparative Example 2

[0059] A method for preparing a white wear-resistant media material based on rare earth element modification of coal gangue, which differs from Example 1 in that only additive B is added, and additive A is not added.

[0060] Comparative Example 3

[0061] A method for preparing a white wear-resistant media material based on rare earth element modification of coal gangue, which differs from Example 1 in that: additive A is lanthanum oxalate.

[0062] Comparative Example 4

[0063] A method for preparing a white wear-resistant media material based on rare earth element modification of coal gangue, which differs from Example 1 in that: additive A is yttrium oxide.

[0064] Comparative Example 5

[0065] A method for preparing a white wear-resistant media material based on rare earth element modification of coal gangue, which differs from Example 1 in that only magnesium fluoride is added as an auxiliary additive.

[0066] Comparative Example 6

[0067] A method for preparing a white wear-resistant media material based on rare earth element modification of coal gangue, which differs from Example 1 in that only coal gangue powder is added.

[0068] The sintering temperature, bulk density, wear resistance coefficient and whiteness of the coal gangue-based white wear-resistant media materials modified with rare earth elements prepared in Examples 1-4 and Comparative Examples 1-6 were tested. The test results are shown in Table 1.

[0069] The sintering temperature test method is as follows: after aging, the material is loaded into a muffle furnace and heated from room temperature to 200℃ at a rate of 5℃-10℃ / min. After holding at 200℃ for 15-30 minutes, the temperature is increased to the target temperature at a rate of 5℃-10℃ / min and held for 2-4 hours. Then, the material is air-cooled to room temperature at a rate of 5℃ / min to obtain a white wear-resistant media material based on rare earth element modification of coal gangue.

[0070] The bulk density test method is as follows: Clean the wear-resistant medium thoroughly, then measure the dry weight of each sample, recorded as m1, accurate to 0.001g; place the dried sample into the container of the apparent porosity bulk density tester, start the vacuum pump, and maintain the sample under the set vacuum for 15 minutes. Then, slowly inject the liquid (neutral water) for the sample to absorb within 1 minute until the liquid completely submerges the sample, with the liquid level at least 20mm above the sample. Keep the sample standing and soaking for 40 minutes. Place the soaked saturated sample into a basket filled with soaking solution (distilled water), and weigh the suspended mass of the saturated sample in the soaking solution, recorded as m2, accurate to 0.001g; remove the sample from the soaking solution, wipe off the liquid adhering to the sample surface with a towel soaked in the soaking solution, and weigh the mass of the saturated sample in the air within 30 seconds, recorded as m3, accurate to 0.001g. When using distilled water as the soaking solution, the density is taken as 1.000g / cm³. 3 .

[0071] The wear resistance coefficient test method is as follows: Weigh the mass m1´ of the wear-resistant medium before the wear resistance test, in g. Weigh 1 kg of wear-resistant medium, 500 g of quartz sand (between 40-60 mesh) and 1 kg of neutral water and put them into a ball mill jar. The quartz sand is added to better simulate the working conditions. The ball mill is run at 80 rpm for 24 h. Take the sample out of the ball mill jar, wash it with water, dry it and weigh it, and record it as m2´.

[0072] The whiteness test method is as follows: The whiteness of the wear-resistant media sample described in this invention is measured by a photoelectric whiteness meter that conforms to the standard. The wear-resistant media sample is crushed and ground into fine powder, sieved, dried at 110℃ for 1 hour, and then pressed into shape. This step is intended to eliminate surface errors. Subsequently, the prepared powder tablet sample is placed on the test bench and the measurement is started. Each sample needs to be measured 3 times and the average value is taken. The average whiteness value is recorded.

[0073] Table 1 Performance Data Sheet

[0074]

[0075] As can be seen from the table above, Example 3 has the best performance. The results show that compared with adding a single rare earth element, adding a rare earth lanthanum / yttrium composite has higher bulk density, wear resistance and whiteness than the single component. Furthermore, the modified rare earth coal gangue wear-resistant media has better performance than the pure coal gangue component.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A white wear-resistant media material based on rare earth element modification of coal gangue, characterized in that: The mixture includes pretreated coal gangue powder, composite additives, auxiliary additives, and binders. The mass ratio of the pretreated coal gangue powder, composite additives, and auxiliary additives is 100:(0.01~20):(0.05~5). The ratio of the amount of binder added to the total mass of the three components (pretreated coal gangue powder, composite additives, and auxiliary additives) is (3~60):

100. The composite additives include additive A and additive B with a mass ratio of 1:(0.5-4). The auxiliary agent A is a lanthanum / yttrium complex, which is prepared by mixing a lanthanum source compound and a yttrium source compound. The mass ratio of the lanthanum source compound to the yttrium source compound is 1:10 to 10:1; The additive B includes one or more of zircon sol, zircon sand, and zirconium oxide.

2. The coal gangue-based white wear-resistant media material modified with rare earth elements according to claim 1, characterized in that: The lanthanum source compound includes one or both of lanthanum oxalate and lanthanum zirconate, and the yttrium source compound includes one or more of yttrium oxide, yttrium aluminate, yttrium hydroxide, yttrium carbonate, and yttrium fluoride.

3. The coal gangue-based white wear-resistant media material modified with rare earth elements according to claim 1, characterized in that: The auxiliary additives include one or more of magnesium fluoride, spodumene, aluminum fluoride, and boron oxide.

4. The coal gangue-based white wear-resistant media material modified with rare earth elements according to claim 1, characterized in that: The aluminum-silicon ratio in the pretreated coal gangue powder is between 0.5 and 1.8, wherein the total percentage content of calcium oxide and magnesium oxide is not greater than 1 wt%, the percentage content of iron oxide is not greater than 1 wt%, and the total percentage content of potassium and sodium is not greater than 1 wt%.

5. The coal gangue-based white wear-resistant media material modified with rare earth elements according to claim 1, characterized in that: The preparation method of the pretreated coal gangue powder is as follows: the coal gangue raw material is crushed, dried, magnetically separated, treated and washed with 20% volume concentration hydrochloric acid, and finally the washed coal gangue is placed in a drying oven for drying and high-energy ball milling.

6. The coal gangue-based white wear-resistant media material modified with rare earth elements according to claim 1, characterized in that: The pretreated coal gangue powder has a particle size of 3-120µm.

7. The method for preparing the rare earth element-modified coal gangue-based white wear-resistant media material according to any one of claims 1-6, characterized in that: Includes the following steps: Composite additives and auxiliary additives are mixed with pretreated coal gangue powder in one step to obtain a precursor material. A binder is added to the precursor material for pelletizing, aging, and sintering. Finally, the material is cooled to room temperature in the furnace to obtain a white wear-resistant medium material based on rare earth element modification of coal gangue.

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