Coal gangue-based white wear-resistant medium material based on rare earth element modification and preparation method thereof

Abstract

The invention provides a coal gangue-based white wear-resistant dielectric material based on rare earth element modification and a preparation method thereof, the material comprises pretreated coal gangue powder, a compound additive, an auxiliary additive and a binder, the mass ratio of the pretreated coal gangue powder to the compound additive to the auxiliary additive is 100: (0.01-20): (0.05-5), the ratio of the addition amount of the binder to the total mass of the pretreated coal gangue powder, the compound additive and the auxiliary additive is (3-60): 100, and the compound additive comprises an additive A and an additive B in a mass ratio of 1: (0.5-4). The coal gangue is adopted as a raw material, the problems of environmental pollution and potential safety hazards caused by coal gangue stockpiling are solved, the preparation process is simple and easy to implement, the utilization rate of the coal gangue is increased, the method can also be used in the fields of ceramic wear-resistant media and the like, and solid waste recycling and collaborative preparation of high-performance ceramic materials are achieved.

Description

Technical Field

[0001] The invention belongs to the field of comprehensive utilization of industrial solid waste, and in particular relates to a gangue-based white wear-resistant medium material modified with rare earth elements and a preparation method thereof. Background Art

[0002] Gangue is solid waste discharged during the excavation, mining, and washing of coal. my country has a massive accumulation of gangue, and its long-term storage and discharge pose significant risks. Its open-air storage encroaches on large amounts of arable land and forestland. Accumulated gangue is prone to collapse and landslides, causing environmental problems such as soil and water pollution. The resulting solid dust also pollutes the atmosphere. In recent years, gangue waste, as a recyclable resource, has demonstrated significant potential for application in the chemical, building materials, metallurgy, and light industry sectors, but its utilization is limited. Therefore, improving the comprehensive utilization rate of gangue and using inexpensive waste materials to produce products with a certain level of economic value can achieve the goals of turning waste into treasure, conserving energy, and protecting the environment, while also having significant economic and social value.

[0003] The main chemical components of coal gangue are aluminum oxide and silicon oxide, which are also commonly used raw materials for ceramic production. Although alumina ceramics, as a grinding medium, are widely used in building sanitary ceramics, industrial ceramics, refractories, specialty cements and other fields, traditional high-aluminum wear-resistant media still face some problems, such as defects such as spots, blistering, adhesion, and wind crystals that may appear during the production process. 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 gangue-based white wear-resistant medium material modified with rare earth elements and a preparation method thereof.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows: In a first aspect, the present invention provides a gangue-based white wear-resistant medium material modified by rare earth elements, comprising pretreated gangue powder, a composite additive, an auxiliary additive and a binder, wherein the mass ratio of the pretreated gangue powder, the composite additive and the auxiliary additive is 100: (0.01~20): (0.05~5), the ratio of the added amount of the binder to the total mass of the three components of the pretreated gangue powder, the composite additive and the auxiliary additive is (3~60): 100, and the composite additive comprises additive A and additive B in a mass ratio of 1: (0.5-4).

[0006] Preferably, the auxiliary agent A is a lanthanum / yttrium compound, which is prepared by mixing a lanthanum source compound and a yttrium source compound.

[0007] Preferably, the lanthanum source compound includes but is not limited to one or both of lanthanum oxalate and lanthanum zirconate.

[0008] 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.

[0009] Preferably, the mass ratio of the lanthanum source compound to the yttrium source compound is 1:10 to 10:1.

[0010] Preferably, the auxiliary agent B includes but is not limited to one or more of zirconium sol, zirconium sand, and zirconium oxide.

[0011] Preferably, the auxiliary additive includes but is not limited to one or more of magnesium fluoride, spodumene, aluminum fluoride, and boron oxide. The auxiliary additive acts as a fluxing agent to facilitate sintering densification by forming a liquid phase at a lower melting point and reducing the sintering temperature.

[0012] Preferably, the pretreated coal gangue powder has an aluminum-silicon ratio of 0.5 to 1.8, a total calcium oxide and magnesium oxide content of not more than 1 wt%, a total potassium and sodium content of not more than 1 wt%, and an iron oxide content of not more than 1 wt%.

[0013] Preferably, the pretreated coal gangue powder is prepared by crushing, drying, and magnetically selecting a coal gangue raw material, treating the coal gangue with 20% volume concentration hydrochloric acid, washing the coal gangue, and finally drying the washed coal gangue in a drying oven and high-energy ball milling.

[0014] Preferably, the crushed coal gangue is dried in a 105-120°C drying oven for 2-4 hours, the magnetic separator is used for 1-3 times of magnetic separation to remove magnetic minerals, the hydrochloric acid treatment is performed at a temperature of 60-80°C for 2-4 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, and activate the surface, and finally the washed coal gangue is dried in a drying oven.

[0015] Preferably, the pretreated coal gangue powder has a particle size of 3-120µm.

[0016] Preferably, the binder includes but is not limited to one or more of water, a 4.35wt% water glass solution, a 5wt% aluminum dihydrogen phosphate solution, a 20wt%-25wt% aluminum sol, and a 5wt%-50wt% silicon sol.

[0017] In a second aspect, the present application also provides a preparation method of the above-mentioned white wear-resistant medium material based on coal gangue modified by rare earth elements, comprising the following steps: The composite additives and auxiliary additives are blended with the pretreated coal gangue powder in one step to obtain a precursor material by fully mixing; a binder is added to the precursor material to perform balling, aging and sintering, and finally air cooling to room temperature in the furnace to obtain the white wear-resistant medium material based on coal gangue modified by rare earth elements.

[0018] Compared with the prior art, the present application has the following advantages: (1) Compared with the traditional technology, the present application uses coal gangue as raw material, solves the environmental pollution and safety hazard problems caused by coal gangue stockpiling, has a simple preparation process, is easy to implement, improves the utilization rate of coal gangue, and realizes the collaborative preparation of solid waste resourceization and high-performance ceramic materials.

[0019] (2) The additive A added in the white wear-resistant medium material based on coal gangue modified by rare earth elements of the present application adopts a lanthanum / yttrium composite, which has the effect of refining the crystal lattice during high-temperature reaction, inhibits abnormal grain growth, produces liquid phase during sintering, and accelerates the densification process. In addition, due to the different affinities of lanthanum and yttrium to different types and states of coloring ions, the combination of the two can more comprehensively inhibit the coloring impurities in the coal gangue raw material. At the same time, due to the reduction of pores during densification, the microstructure is optimized, the light scattering loss is reduced, the whitening effect is achieved, and the whiteness of the wear-resistant medium material is improved. In addition, there is a synergistic effect between the additive A and the additive B. The liquid phase environment generated by the additive A can promote the uniform dispersion of the additive B in the coal gangue matrix, making the combination of the two more firm. The high-density matrix created by the grain refinement of the additive A provides support for fully exerting the strengthening effect of the additive B. The combined effect of the fine-grained strengthening of the additive A and the phase transformation toughening of the additive B improves the wear resistance of the white wear-resistant medium material based on coal gangue. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A microstructure diagram of the white wear-resistant medium material based on coal gangue modified by rare earth elements prepared in Example 1; Figure 2 A microstructure diagram of the white wear-resistant medium material based on coal gangue modified by rare earth elements prepared in Comparative Example 4. DETAILED DESCRIPTION

[0021] The embodiments of the present application are described in detail below. The embodiments described below are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0022] In the present text, unless otherwise defined, all technical and scientific terms used have the same meaning as would be commonly understood by one of ordinary skill in the art to which this application belongs.

[0023] In the present text, where values are described as ranges, it is to be understood that the disclosure includes disclosure of all possible sub-ranges within the range, and specific numerical values falling within the range, regardless of whether the specific numerical values or the specific sub-ranges are explicitly stated.

[0024] In the present text, the term "plurality" and the like, if not otherwise specified, means greater than or equal to two in number. For example, "one or more" means one or more than one.

[0025] In the present text, the terms "preferably", "more preferably" are used to describe embodiments or examples that are better in effect, and it is understood that they do not constitute a limitation on the scope of protection of the present application.

[0026] In the present text, the term "further" and the like are used for the purpose of description, indicating a difference in content, but should not be understood as a limitation on the scope of protection of the present application.

[0027] In the present text, the term "and / or" is a description of the relationship between objects, indicating that there can be three relationships. For example, A and / or B, means: A or B, or A and B, the three relationships.

[0028] In the present text, the term "about" means + / - 10% of the specified value, preferably + / - 5%, more preferably + / - 1%.

[0029] In the present text, "comprising", "including", "having", "containing" and the like are open terms, i.e. meaning including but not limited to.

[0030] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as would be commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application.

[0031] The present application will be described in detail below with reference to the examples.

[0032] Example 1 A preparation method of a coal gangue-based white wear-resistant medium material modified based on rare earth elements comprises the following steps: (1) Select coal gangue raw materials, crush them, and dry the crushed coal gangue in a 105°C drying box for 4h. Use a magnetic separator to remove magnetic minerals for 3 times. Treat the coal gangue powder after preliminary iron removal with 20% hydrochloric acid by volume at 80°C for 2h 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 dry the washed coal gangue in a drying box.

[0033] (2) After the carbon removal treatment, the mass percentage of each component of the coal gangue powder is: aluminum oxide ≤47.3%, silicon oxide ≤52.4%, calcium oxide + magnesium oxide ≤0.5%, iron oxide ≤1%, potassium + sodium ≤1%, and the aluminum-silicon ratio of the coal gangue powder is 0.9. Further refine the particles of the coal gangue powder after high-energy ball milling to improve the uniformity of the powder, and make the particle size of the powder be 20µm.

[0034] (3) Mix lanthanum oxalate and yttrium oxide according to a mass ratio of 1:2 to obtain an additive A. Mix the additive A and zirconium sol according to a mass ratio of 1:3 to obtain a composite additive. Directly mix the composite additive, magnesium fluoride, and the coal gangue powder after high-energy ball milling according to a mass ratio of 2:0.5:100 to obtain a precursor material. Then add 30% of the total mass of the precursor material of neutral water to form balls, age, sinter, and finally air cool to room temperature in the furnace to obtain a coal gangue-based white wear-resistant medium material modified based on rare earth elements.

[0035] Example 2 A preparation method of a coal gangue-based white wear-resistant medium material modified based on rare earth elements includes the following steps: (1) Select coal gangue raw materials, crush them, and dry the crushed coal gangue in a 120°C drying box for 2h. Use a magnetic separator to remove magnetic minerals for 3 times. Treat the coal gangue powder after preliminary iron removal with 20% hydrochloric acid by volume at 60°C for 4h 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 dry the washed coal gangue in a drying box.

[0036] (2) After the carbon removal treatment, the mass percentage of each component of the coal gangue powder is: aluminum oxide ≤47.3%, silicon oxide ≤52.4%, calcium oxide + magnesium oxide ≤0.5%, iron oxide ≤1%, and potassium + sodium ≤1%. Add quartz sand for component regulation. After adjustment, the aluminum-silicon ratio of the coal gangue powder is 0.8. Further refine the particles of the coal gangue powder after high-energy ball milling to improve the uniformity of the powder, and make the particle size of the powder be 10µm.

[0037] (3) The lanthanum oxalate and yttrium carbonate are mixed in a mass ratio of 10:1 to obtain an additive A, the additive A and zircon are mixed in a mass ratio of 1:1 to obtain a composite additive, the composite additive, aluminum fluoride and the coal gangue powder after high-energy ball milling are directly blended in a mass ratio of 0.01:0.05:100 in one step, and the precursor material is obtained after fully mixing. Then, 60% of the total mass of the precursor material is added to neutral water to form balls, age, sinter, and finally air cool to room temperature in the furnace to obtain a coal gangue-based white wear-resistant medium material modified based on rare earth elements.

[0038] Example 3 A preparation method of a coal gangue-based white wear-resistant medium material modified based on rare earth elements includes the following steps: (1) Select coal gangue raw materials, crush them, and dry the crushed coal gangue in a drying box at 110°C for 3h. Use a magnetic separator to remove magnetic minerals once. Treat the coal gangue powder after initial iron removal with 20% hydrochloric acid by volume at 70°C for 4h to remove carbonate minerals in the coal gangue, reduce the generation of decomposition gas during subsequent high-temperature treatment, dissolve surface impurities, activate the surface, and finally dry the washed coal gangue in a drying box.

[0039] (2) After the carbon removal treatment, the mass percentage of each component of the coal gangue powder is: alumina ≤47.3%, silica ≤52.4%, calcium oxide + magnesium oxide ≤0.5%, iron oxide ≤1%, and potassium + sodium ≤1%. Add silica to regulate the components. After adjustment, the aluminum-silicon ratio of the coal gangue powder is 0.7. The coal gangue powder after adjusting the aluminum-silicon ratio is further refined by high-energy ball milling to improve the uniformity of the powder, and the particle size is 5µm.

[0040] (3) The lanthanum zirconate and yttrium hydroxide are mixed in a mass ratio of 1:10 to obtain an additive A, the additive A and zirconium oxide are mixed in a mass ratio of 1:4 to obtain a composite additive, the composite additive, boron oxide and the coal gangue powder after high-energy ball milling are directly blended in a mass ratio of 20:5:100 in one step, and the precursor material is obtained after fully mixing. Then, 20% of the total mass of the precursor material is added to an aluminum dihydrogen phosphate solution with a concentration of 5wt%, and then the ball forming, aging, sintering and air cooling to room temperature in the furnace are carried out to obtain a coal gangue-based white wear-resistant medium material modified based on rare earth elements.

[0041] Example 4 A preparation method of a coal gangue-based white wear-resistant medium material modified based on rare earth elements includes the following steps: (1) Select the coal gangue raw material and crush it. Place the crushed coal gangue in a drying oven at 100℃ for 4 hours, use a magnetic separator to perform magnetic separation three times to remove magnetic minerals, and treat the coal gangue powder after preliminary iron removal with 20% volume concentration of 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.

[0042] (2) The mass percentage of each component of the gangue powder after carbon removal treatment is: aluminum oxide ≤ 47.3%, silicon oxide ≤ 52.4%, calcium oxide + magnesium oxide ≤ 0.5%, iron oxide ≤ 1%, potassium + sodium ≤ 1%; aluminum oxide is added to adjust the components, and the aluminum-silicon ratio of the adjusted gangue powder is 1.0. The gangue powder with adjusted aluminum-silicon ratio is further refined by high-energy ball milling to improve the uniformity of the powder and make its particle size 50µm.

[0043] (3) Lanthanum zirconate and yttrium fluoride were mixed in a mass ratio of 3:2 to obtain additive A, additive A was mixed with zirconium oxide in a mass ratio of 1:0.5 to obtain a composite additive, the composite additive and boron oxide were directly blended with the high-energy ball-milled gangue powder in a mass ratio of 4:1:100 in one step, and the precursor material was fully mixed, and then 45% of the total mass of the precursor material was added with a water glass solution, wherein the concentration of the water glass solution was 4.35wt%, and then the mixture was balled, aged, and sintered, and finally air-cooled to room temperature to obtain a gangue-based white wear-resistant medium material modified with rare earth elements.

[0044] Comparative Example 1 A method for preparing a gangue-based white wear-resistant medium material modified with rare earth elements, which differs from Example 1 in that only additive A is added, and additive B is not added.

[0045] Comparative Example 2 A method for preparing a gangue-based white wear-resistant medium material modified with rare earth elements, which differs from Example 1 in that only additive B is added, and additive A is not added.

[0046] Comparative Example 3 A method for preparing a gangue-based white wear-resistant medium material modified with rare earth elements, which differs from Example 1 in that the additive A is lanthanum oxalate.

[0047] Comparative Example 4 A method for preparing a gangue-based white wear-resistant medium material modified with rare earth elements, which differs from Example 1 in that the auxiliary agent A is yttrium oxide.

[0048] Comparative Example 5 A preparation method of a coal gangue-based white wear-resistant medium material modified by rare earth elements, which is different from example 1 in that only auxiliary additive magnesium fluoride is added.

[0049] Comparative example 6 A preparation method of a coal gangue-based white wear-resistant medium material modified by rare earth elements, which is different from example 1 in that only coal gangue powder is added.

[0050] The sintering temperature, bulk density, wear-resistant coefficient and whiteness of the coal gangue-based white wear-resistant medium material modified by rare earth elements prepared in examples 1-4 and comparative examples 1-6 are tested, and the test results are shown in table 1.

[0051] The sintering temperature test method is as follows: after aging, the sample is loaded into a muffle furnace, and the temperature is raised from room temperature to 200°C at a rate of 5-10°C / min, and then kept at 200°C for 15-30 min; the temperature is raised to the target temperature at a rate of 5-10°C / min, and kept for 2-4 h, and then cooled to room temperature at a rate of 5°C / min to obtain the coal gangue-based white wear-resistant medium material modified by rare earth elements.

[0052] The bulk density test method is as follows: the wear-resistant medium is cleaned, and then the dry weight of each sample is measured, recorded as m1, accurate to 0.001 g; the dried sample is placed in a container of a gas porosity container weight tester, a vacuum pump is started, and the sample is kept at the set vacuum degree for 15 min, then neutral water is slowly injected into the sample within 1 min, until the liquid completely immerses the sample, and the liquid level is at least 20 mm higher than the sample, and the sample is kept soaking for 40 min. The saturated sample after immersion is placed in a basket suspended in a container full of immersion liquid (distilled water), and the suspended mass of the saturated sample in the immersion liquid is measured, recorded as m2, accurate to 0.001 g; the sample is taken out of the immersion liquid, and the liquid adhered to the surface of the sample is wiped off with a towel full of immersion liquid, and the mass of the saturated sample in the air is measured within 30 s, recorded as m3, accurate to 0.001 g; when distilled water is used as the immersion liquid, the density is taken as 1.000 g / cm 3 .

[0053] The wear-resistant coefficient test method is as follows: the mass of the wear-resistant medium before wear-resistant test is measured as m1´, in g; 1 kg of wear-resistant medium, 500 g of quartz sand (40-60 mesh) and 1 kg of neutral water are loaded into a ball mill jar, and the quartz sand is added to better simulate the working condition; the sample is ball milled on a ball mill test machine at a speed of 80 revolutions per minute for 24 h, taken out of the ball mill jar, washed with water, dried and weighed, recorded as m2´.

[0054] The whiteness test test method is that the whiteness of the wear-resistant medium sample is measured by a standard-compliant photoelectric whiteness meter. The wear-resistant medium sample is crushed and ground into fine powder, dried at 110 DEG C for 1 h after sieving, and then pressed into a shape, which aims to eliminate the curved surface error; then the prepared powder tablet sample is placed on the test table to start measurement, each sample needs to be measured for 3 times to take the average value, and the average value of the whiteness is recorded.

[0055] Table 1 Performance data table

[0056] As can be seen from the above table, the performance of example 3 is the best, and the results show that compared with adding a single rare earth element, adding a rare earth lanthanum / yttrium compound, the bulk density, wear resistance and whiteness of the wear-resistant medium are higher than those of a single component, and the performance of the modified rare earth coal gangue wear-resistant medium is better than that of pure coal gangue component.

[0057] The above only describes the preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A gangue-based white wear-resistant medium material modified with rare earth elements, characterized by: The invention comprises pretreated gangue powder, composite additive, auxiliary additive and binder, wherein the mass ratio of the pretreated gangue powder, composite additive and auxiliary additive is 100:(0.01-20):(0.05-5), the ratio of the added amount of the binder to the total mass of the three components of the pretreated gangue powder, composite additive and auxiliary additive is (3-60):100, and the composite additive comprises auxiliary agent A and auxiliary agent B in a mass ratio of 1:(0.5-4).

2. The rare earth element-modified gangue-based white wear-resistant medium material according to claim 1, characterized in that: The auxiliary agent A is a lanthanum / yttrium complex, and the auxiliary agent A is prepared by mixing a lanthanum source compound and a yttrium source compound.

3. The rare earth element-modified gangue-based white wear-resistant medium material according to claim 2, 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.

4. The rare earth element-modified gangue-based white wear-resistant medium material according to claim 2, characterized in that: The mass ratio of the lanthanum source compound to the yttrium source compound is 1:10 to 10:

1.

5. The rare earth element-modified gangue-based white wear-resistant medium material according to claim 1, characterized in that: The additive B includes one or more of zircon sol, zircon sand, and zirconium oxide.

6. The gangue-based white wear-resistant medium 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.

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

8. The gangue-based white wear-resistant medium 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, and magnetically separated, and then treated and washed with 20% volume concentration hydrochloric acid. Finally, the washed coal gangue is placed in a drying oven for drying and high-energy ball milling.

9. The gangue-based white wear-resistant medium material modified with rare earth elements according to claim 1, characterized in that: The particle size of the pretreated gangue powder is 3-120 μm.

10. The method for preparing the rare earth element-modified gangue-based white wear-resistant medium material according to any one of claims 1 to 9, characterized in that: The steps include: The composite auxiliary agent, auxiliary additive and pretreated gangue powder are blended in one step and fully mixed to obtain a precursor material; a binder is added to the precursor material to perform balling, aging and sintering, and finally air-cooled to room temperature in the furnace to obtain a gangue-based white wear-resistant medium material modified with rare earth elements.

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