An alkaline-resistant gangue solid waste microcrystalline material for ocean engineering and its preparation method

Abstract

The present invention relates to an alkali-resistant coal gangue solid waste microcrystalline material for marine engineering and a preparation method thereof. The basic glass raw materials of the coal gangue solid waste microcrystalline material include: 40-70 parts of coal gangue, 20-40 parts of silica sand, 10-20 parts of calcium fluoride, 2-8 parts of zinc oxide and 1-6 parts of aluminum oxide. The present invention has a good utilization rate of coal gangue solid waste, and mullite (Al 4.64 Si 1.36 O 9.68 ) and zinc spinel (ZnAl2O4), the small-sized spherical zinc spinel and the large-sized spherical mullite crystals grow alternately to form a dense crystal structure, which ultimately makes the coal gangue solid waste microcrystalline material prepared by the present invention have excellent alkali resistance and is expected to be used as a marine engineering material.

Description

Technical Field

[0001] The present invention relates to the field of comprehensive utilization of coal gangue solid waste, and particularly to an alkali-resistant coal gangue solid waste microcrystalline material for ocean engineering and a preparation method thereof. Background Art

[0002] Approximately 71% of the Earth's surface is ocean. Ocean engineering such as marine transportation, offshore oil platforms, and offshore wind power generation has made great contributions to the development of the national economy. However, the losses caused by ocean corrosion are as high as trillions of yuan per year and cannot be underestimated. Seawater can not only corrode metal materials but also inorganic non-metallic materials. Silicate glass is generally not alkali-resistant. When immersed in weakly alkaline (7.5 < pH < 8.2) seawater for a long time, the silicon-oxygen framework (≡Si-O-Si≡) will gradually be destroyed by the erosion of OH - ions.

[0003] Coal gangue is the waste residue generated during coal mining and washing. Among many industrial waste residues, the discharge amount of coal gangue ranks first and increases year by year with the large-scale development and use of coal. The stacking of coal gangue not only occupies a large amount of land but also easily causes ecological damage and environmental pollution. Research shows that coal gangue contains a chemical composition similar to that of glass-ceramics, and the proportion of silicon and aluminum oxides is as high as about 70%. Preparing glass-ceramics with coal gangue as the raw material can not only turn coal gangue into treasure and realize resource utilization but also avoid safety and ecological environment problems caused by the large-scale stacking of coal gangue.

[0004] In the existing reports, Luo Bing et al. tried to prepare glass-ceramics by direct sintering method with a small dose (3 g) of coal gangue and tested its alkali resistance. The test was carried out by soaking in NaOH (1 wt%) solution at room temperature for 26 d. The optimal alkali weight loss rate of this coal gangue glass-ceramics was about 1.25%. In addition, Zhan Lingli et al. disclosed a preparation method of coal gangue high-aluminum glass-ceramics with an 85 g (70 wt%) dosage. The alkali resistance test was carried out by soaking in NaOH (10 wt%) solution at room temperature for 24 h. Although the utilization rate of coal gangue was very high, the alkali weight loss rate reached 1.49%. It is not difficult to find that the alkali resistance of the above-mentioned coal gangue solid waste microcrystalline materials is not good and needs to be further improved. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies, provide an alkali-resistant coal gangue solid waste microcrystalline material for ocean engineering and a preparation method thereof, and solve the technical problem that the alkali resistance of coal gangue solid waste microcrystalline materials in the existing technology is not good.

[0006] To achieve the above technical purpose, the technical solution provided by the present invention is:

[0007] In a first aspect, the present invention provides an alkali-resistant coal gangue solid waste microcrystalline material for marine engineering. The basic glass raw materials of the coal gangue solid waste microcrystalline material include, by weight: 40 to 70 parts of coal gangue, 20 to 40 parts of silica sand, 10 to 20 parts of calcium fluoride, 2 to 8 parts of zinc oxide and 1 to 6 parts of aluminum oxide.

[0008] In a second aspect, the present invention provides a method for preparing an alkali-resistant coal gangue solid waste microcrystalline material for marine engineering, comprising the following steps: (1) weighing the raw materials of each component of a basic glass and mixing them evenly to form a batch material; (2) subjecting the batch material to high-temperature melting, molding and annealing to obtain a basic glass; and (3) crystallizing the basic glass to obtain a coal gangue solid waste microcrystalline material.

[0009] Compared with the prior art, the beneficial effects of the present invention include:

[0010] The alkali-resistant coal gangue solid waste microcrystalline material provided by the present invention has good utilization rate and tolerance for coal gangue solid waste. Secondly, combined with the characteristics of high Al content in coal gangue solid waste, the present invention further introduces a Zn source and obtains mullite (Al 4.64 Si 1.36 O 9.68 ) and zinc spinel (ZnAl2O4). In the microcrystalline material, the crystal size of the mullite phase is relatively large (150-200 nm), while the size of the zinc spinel phase is relatively small (20-50 nm). The small-sized spherical zinc spinel and the large-sized spherical mullite crystals grow alternately to form a dense crystal structure, which ultimately makes the coal gangue solid waste microcrystalline material prepared by the present invention have excellent alkali resistance, and the alkali resistance (NaOH, 10 wt%) weight loss rate is 0.45-0.51%; the high utilization rate of coal gangue and the excellent alkali resistance make the coal gangue solid waste microcrystalline material proposed by the present invention promising to be used as marine engineering materials. The present invention provides a powerful reference for solving the problems of coal gangue solid waste accumulation, resource waste and environmental pollution; in addition, the preparation method of the present invention is simple and easy. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a process diagram of a method for preparing alkali-resistant coal gangue solid waste microcrystalline material for marine engineering of the present invention;

[0012] Figure 2 These are the X-ray diffraction test results of the microcrystalline materials prepared in Comparative Examples 1-2 and Examples 1-3 of the present invention;

[0013] Figure 3 This is the SEM scanning electron microscope test result of the microcrystalline material prepared in Example 1 of the present invention;

[0014] Figure 4These are the test results of the alkali resistance weight loss rate of the microcrystalline materials prepared in Comparative Examples 1-2 and Examples 1-3 of the present invention. Detailed implementation manners

[0015] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0016] In a first aspect, the present invention provides an alkali-resistant coal gangue solid waste microcrystalline material for ocean engineering. By weight, the basic glass raw materials of the coal gangue solid waste microcrystalline material include: 40-70 parts of coal gangue, 20-40 parts of silica sand, 10-20 parts of calcium fluoride, 2-8 parts of zinc oxide, and 1-6 parts of alumina.

[0017] In some specific implementation manners of the present invention, after high-temperature treatment and XRF determination, by weight percentage, the components of the coal gangue include: 50-55% of SiO2, 22-28% of Al2O3, 2-3% of K2O, 1-4% of Fe2O3, 1-2% of CaO, 1-2% of MgO, 0-1% of Na2O, 0-2% of TiO2; the balance is a gas mixture, etc., mainly including 5-10% of CO2+SO3.

[0018] Except for fluorine, the components of the microcrystalline material of the present invention are converted into oxides as follows: 50-65% of SiO2, 11-20% of Al2O3, 5.5-14% of F, 2-8% of ZnO, 0.5-3% of K2O, 0.5-2% of CaO, 0.5-2% of MgO, 0-0.5% of Na2O, 0.5-2% of Fe2O3, 0-1% of TiO2.

[0019] The above basic glass components are mainly introduced by coal gangue (SiO2, Fe2O3, TiO2, Al2O3, CaO, MgO, K2O, etc.), mineral raw material silica sand (SiO2), and chemically pure reagents CaF2, Al2O3, ZnO. Except for the above three chemical raw materials, all other components of the microcrystalline material of the present invention are mineral raw materials, and the main component is solid waste coal gangue, which solves the problems of solid waste accumulation and environmental pollution, effectively reduces the production cost of microcrystalline glass, saves resources, and is also expected to be used in ocean engineering.

[0020] In the present invention, chemical reagents CaF2, Al2O3, and ZnO are introduced. CaF2 serves as a crystal nucleating agent of the system; ZnO serves as a flux and a network outer body to make the structure of the microcrystalline material tend to be compact; Al2O3 serves as a network intermediate to help improve the chemical stability of the microcrystalline material. The present invention further adjusts the raw material components and preparation process conditions, not only realizing the recycling of coal gangue solid waste, but also the prepared coal gangue solid waste microcrystalline material has excellent alkali resistance and is expected to be used in marine engineering materials.

[0021] In some specific embodiments of the present invention, the alkali-resistant coal gangue solid waste microcrystalline material prepared by the present invention has an alkali-resistant (NaOH, 10 wt%) weight loss rate of less than 0.51%, and the optimal alkali-resistant weight loss rate is 0.45%; the grain size is 20 to 200 nm, and contains mullite (Al 4.64 Si 1.36 O 9.68 ) and zinc spinel (ZnAl2O4); and in the microstructure of coal gangue solid waste glass-ceramics, the main crystal phase is mullite (Al2O4) with an average grain size of 150-200 nm. 4.64 Si 1.36 O 9.68 ), with a content of 81% to 87%; the secondary crystalline phase is zinc spinel (ZnAl2O4) with an average grain size of 20 to 50 nm, with a content of 13% to 19%. Small-sized spherical zinc spinel and large-sized spherical mullite crystals grow alternately to form a dense crystal structure, which makes the microcrystalline material more compact as a whole.

[0022] In some specific implementation examples of the present invention, the basic glass composition of the alkali-resistant coal gangue solid waste microcrystalline material includes, by weight: 45-55 parts of coal gangue, 20-40 parts of silica sand, 10-20 parts of calcium fluoride, 2-5 parts of zinc oxide, and 3-4 parts of aluminum oxide.

[0023] In some specific implementation examples of the present invention, the basic glass composition of the alkali-resistant coal gangue solid waste microcrystalline material includes, by weight: 50 parts of coal gangue, 25-35 parts of silica sand, 12-18 parts of calcium fluoride, 4-5 parts of zinc oxide, and 3-4 parts of aluminum oxide.

[0024] In the present invention, too little ZnO content will lead to poor raw material melting, because ZnO not only acts as a network body, but also as a flux. If the content is too little, the raw material melting is insufficient, and if the content is too much, the cost will increase. If the Al2O3 content is too little, the crystal growth is insufficient, because the mullite (Al 4.64 Si 1.36 O 9.68 ) and zinc spinel (ZnAl2O4) are inseparable from the Al element, and a high Al2O3 content will also increase the cost.

[0025] In a second aspect, the present invention provides a method for preparing an alkaline-resistant coal gangue solid waste microcrystalline material for ocean engineering. Refer to Figure 1 , which includes the following steps:

[0026] (1) Weigh each component raw material of the base glass and mix them evenly to make a batch material;

[0027] (2) The batch material is melted at high temperature, formed, and annealed, and then the base glass is obtained;

[0028] (3) The base glass is subjected to crystallization treatment to obtain a coal gangue solid waste microcrystalline material.

[0029] Preferably, in step (2), the high-temperature melting temperature is 1400 - 1550 °C, and the high-temperature melting time is 2 - 4 hours. Within this range, it can effectively ensure that the glass melt is fully clarified and reduce the presence of bubbles in the glass melt.

[0030] Preferably, in step (2), the annealing temperature is 500 - 650 °C; the annealing time is 2 - 4 hours. Within this range, it can ensure that the base glass product is fully annealed, eliminate internal stress, and improve the quality of the base glass.

[0031] Preferably, in step (3), the crystallization treatment temperature is 950 - 1150 °C; the crystallization treatment time is 1 - 3 hours. Within this range, it can ensure that the crystal materials in the base glass grow completely, and effectively improve the physical and chemical properties of the coal gangue solid waste microcrystalline material.

[0032] The present invention uses coal gangue solid waste as the main raw material, forms a suitable microcrystalline material formula by combining with other components, and adopts corresponding preparation processes to prepare a coal gangue solid waste microcrystalline material with excellent alkali resistance and promising for use in ocean engineering, which will further realize the transformation of coal gangue solid waste into valuable resources.

[0033] The following further elaborates on the present invention through specific examples.

[0034] The raw materials used in the embodiments of the present invention are coal gangue associated with coal production in a certain coal mine, purchased mineral raw materials, and chemical raw materials, allowing for trace amounts of inevitable impurities; the melting of the glass is carried out using a high-temperature melting furnace; annealing is carried out in an annealing furnace; and crystallization is carried out in a crystallization furnace.

[0035] For each of the following examples and comparative examples of the present invention, the alkali resistance of the obtained microcrystalline material was tested with reference to the "Method for Determining Acid and Alkali Resistance of Domestic Ceramic Materials" (national standard GB / T 4738-2015). Specifically: The prepared microcrystalline material was subjected to steps of crushing into powder, sieving, cleaning, and drying. About 1 g of microcrystalline material specimens with a particle size between 0.9 and 1.6 mm were weighed and heated to gentle boil in (25 ± 5) mL of NaOH (10 wt%) solution for 1 h, and then cleaned and dried for alkali resistance testing.

[0036] Example 1

[0037] The selected basic glass formula is: coal gangue: 50 parts; silica sand: 30.33 parts; CaF2: 15 parts; ZnO: 4.67 parts; Al2O3: 3.33 parts.

[0038] Weigh each raw material accurately according to the above proportions to prepare a basic glass batch. The batch was melted at 1500 °C for 3 h, and after high-temperature homogenization and clarification, a glass melt was obtained. After the glass melt was formed by the casting method, it entered an annealing furnace and was annealed at 600 °C for 2 h, and then entered a crystallization furnace and was crystallized at 1000 °C for 2 h, and cooled with the furnace to obtain an alkali-resistant coal gangue solid waste microcrystalline material; after crushing into powder, sieving, cleaning, and drying, it was tested.

[0039] Except for fluorine, the components of the microcrystalline material prepared in this example were converted into oxides as follows: SiO2 60.08%, Al2O3 17.40%, F 12.67%, ZnO 4.93%, K2O 1.41%, CaO 0.63%, MgO 0.65%, Na2O 0.19%, Fe2O3 1.55%, TiO2 0.48%.

[0040] From Figure 2 the XRD results, the characteristic peaks of mullite (Al 4.64 Si 1.36 O 9.68 ), and zinc spinel (ZnAl2O4) are obvious. Therefore, the coal gangue solid waste microcrystalline material prepared by the present invention contains two crystal phases of mullite (Al 4.64 Si 1.36 O 9.68 ) and zinc spinel (ZnAl2O4).

[0041] From Figure 3 the SEM scanning electron micrographs, it can be seen that the grain size of the coal gangue solid waste microcrystalline material is 20 - 200 nm. By Figure 2 and combined with professional software analysis, it can be known that the main crystal phase is mullite (Al 4.64 Si1.36 O 9.68 ), with a content of 81.6%; the secondary crystalline phase is zinc spinel (ZnAl2O4) with an average grain size of 20 - 50 nm, and the content is 18.4%.

[0042] As Figure 4 shown, the coal gangue solid waste microcrystalline material prepared in this example has good alkali resistance, and the weight loss rate of alkali resistance (NaOH, 10wt%) is 0.47%.

[0043] Comparative Example 1

[0044] Compared with Example 1, the difference is only that: alumina is removed; that is, the basic glass formula is selected as: coal gangue (50 parts); silica sand (30.33 parts); CaF2 (15 parts); ZnO (4.67 parts), without adding Al2O3 additionally.

[0045] Accurately weigh each raw material according to the above ratio to prepare a basic glass batch. The batch is melted at 1500 °C for 3 hours, and after high-temperature homogenization and clarification, a glass melt is obtained. After the glass melt is formed by the casting method, it enters an annealing furnace and is annealed at 600 °C for 2 hours, and then enters a crystallization furnace and is crystallized at 1000 °C for 2 hours, and is cooled with the furnace. After crushing, sieving, washing and drying, it is tested.

[0046] From Figure 2 the XRD results, the intensity of the crystallization peak is weak, and the characteristic peaks of mullite (Al 4.64 Si 1.36 O 9.68 ), and zinc spinel (ZnAl2O4) are almost absent. Therefore, it cannot be called a microcrystalline material yet. The poor compactness of the structure leads to poor alkali resistance, which may be related to the too small content of alumina in the coal gangue.

[0047] As Figure 4 shown, the weight loss rate of alkali resistance (NaOH, 10 wt%) of the coal gangue solid waste microcrystalline material prepared in this comparative example is 2.16%.

[0048] Comparative Example 2

[0049] Compared with Example 1, the difference is only that: the amount of Al2O3 used in the basic glass formula is only reduced; that is, the basic glass formula is selected as: coal gangue: 50 parts; silica sand: 30.33 parts; CaF2: 15 parts; ZnO: 4.67 parts; Al2O3: 1.67 parts.

[0050] Weigh each raw material accurately according to the above ratios to prepare the basic glass batch. The batch is melted at 1500 °C for 3 hours, and after high-temperature homogenization and clarification, the glass melt is obtained. After the glass melt is formed by the casting method, it enters the annealing furnace and is annealed at 600 °C for 2 hours. Subsequently, it enters the crystallization furnace and is crystallized at 1000 °C for 2 hours, and then cooled in the furnace. After crushing, sieving, cleaning, and drying, it is tested.

[0051] From Figure 2 the XRD results, the crystallization peak intensity is slightly enhanced compared to Comparative Example 1, but the characteristic peaks of mullite (Al 4.64 Si 1.36 O 9.68 ) and zinc spinel (ZnAl2O4) are still not obvious, indicating that the content of alumina in the system is insufficient.

[0052] As Figure 4 shown, the weight loss rate of the coal gangue solid waste microcrystalline material prepared in this comparative example against alkali (NaOH, 10 wt%) is 2.07%.

[0053] Comparative Example 3

[0054] Compared with Example 1, the difference is only that: the amount of Al2O3 is only increased in the basic glass formula; that is, the selected basic glass formula is: coal gangue: 50 parts; silica sand: 30.33 parts; CaF2: 15 parts; ZnO: 4.67 parts; Al2O3: 5 parts.

[0055] Weigh each raw material accurately according to the above ratios to prepare the basic glass batch. The batch is melted at 1500 °C for 3 hours, and after high-temperature homogenization and clarification, the glass melt is obtained. After the glass melt is formed by the casting method, it enters the annealing furnace and is annealed at 600 °C for 2 hours. Subsequently, it enters the crystallization furnace and is crystallized at 1000 °C for 2 hours, and then cooled in the furnace. After crushing, sieving, cleaning, and drying, it is tested.

[0056] Abnormalities occurred during the high-temperature melting step. When casting and forming, it was found that there were unmelted solid components dripping. After cooling, it could be seen that there were particles with metallic luster at the bottom of the glass. It is speculated that it may be due to the excessive content of Al2O3. Compared with Example 1 or Comparative Example 1, the components that assist in melting in the system, such as Na2O, K2O, and ZnO, remain unchanged, so abnormalities occurred during melting.

[0057] In summary, compared with the content of Al2O3 in Comparative Examples 1 - 3 being too little or too much, the amount of Al2O3 used in Example 1 is 3.33 parts. From Figure 2 the XRD results, for mullite (Al 4.64 Si 1.36 O 9.68)(and the crystallization peaks of zinc spinel (ZnAl2O4) are obvious, and the alkali resistance is also the best. The weight loss rate of alkali resistance (NaOH, 10 wt%) is 0.47%. Therefore, with the change of the dosage of the main raw material coal gangue (40 - 70 parts) in the present invention, it is preferred to add 1 - 6 parts of alumina, and the further preferred range is 3 - 4 parts. The most preferred is the mass ratio of coal gangue to alumina of 50:(3 - 4).

[0058] Comparative Example 4

[0059] Compared with Example 1, the difference is only that: zinc oxide is removed; that is, the selected basic glass formula is: coal gangue: 50 parts; silica sand: 30.33 parts; CaF2: 15 parts; Al2O3: 3.33 parts; no additional ZnO is added.

[0060] Accurately weigh each raw material according to the above ratio, prepare the basic glass batch, melt the batch at 1500 °C for 3 hours, obtain the glass melt after high-temperature homogenization and clarification, after the glass melt is formed by the casting method, enter the annealing furnace and keep it at 600 °C for 2 hours for annealing treatment, then enter the crystallization furnace and keep it at 1000 °C for 2 hours for crystallization treatment, cool with the furnace, and after crushing, sieving, cleaning and drying, perform tests.

[0061] The test phenomenon is similar to that of Comparative Example 3. Abnormalities occurred during the high-temperature melting step, and the glass melt could not be melted evenly. This may be due to the lack of the flux ZnO in the system. Only the trace amounts of Na2O and K2O in the coal gangue for fluxing are far from enough.

[0062] Example 2

[0063] The selected basic glass formula is: coal gangue: 50 parts; silica sand: 30.33 parts; CaF2: 15 parts; ZnO: 2.33 parts; Al2O3: 3.33 parts.

[0064] Accurately weigh each raw material according to the above ratio, prepare the basic glass batch, melt the batch at 1500 °C for 3 hours, obtain the glass melt after high-temperature homogenization and clarification, after the glass melt is formed by the casting method, enter the annealing furnace and keep it at 600 °C for 2 hours for annealing treatment, then enter the crystallization furnace and keep it at 1100 °C for 2 hours for crystallization treatment, cool with the furnace, obtain the alkali-resistant coal gangue solid waste microcrystalline material; after crushing, sieving, cleaning and drying, perform tests.

[0065] Except for fluorine, the components of the microcrystalline material obtained in this example, when converted into oxides, are: SiO2 61.60%, Al2O3 17.84%, F 12.99%, ZnO 2.52%, K2O 1.44%, CaO 0.64%, MgO 0.67%, Na2O 0.20%, Fe2O3 1.59%, TiO2 0.50%.

[0066] From Figure 2 the XRD results of 4.64 Si 1.36 O 9.68 ), it can be seen that the characteristic peaks of mullite (Al

[0067] As Figure 4 shown, the microcrystalline coal gangue solid waste material obtained in this example has good alkali resistance, and the weight loss rate in alkali (NaOH, 10wt%) is 0.51%.

[0068] Example 3

[0069] Compared with Example 2, only the ZnO content was increased in the basic glass formula, that is, the selected basic glass formula is: coal gangue: 50 parts; silica sand: 30.33 parts; CaF2: 15 parts; ZnO: 7 parts; Al2O3: 3.33 parts.

[0070] Accurately weigh each raw material according to the above ratio, prepare the basic glass batch. The batch is melted at 1500 °C for 3 hours, and after high-temperature homogenization and clarification, the glass melt is obtained. After the glass melt is formed by the casting method, it enters the annealing furnace and is annealed at 600 °C for 2 hours, and then enters the crystallization furnace and is crystallized at 1100 °C for 2 hours, and is cooled with the furnace to obtain an alkali-resistant coal gangue solid waste microcrystalline material; after being crushed, sieved, washed and dried, it is tested.

[0071] Except for fluorine, the components of the microcrystalline material obtained in this example, when converted into oxides, are: SiO2 58.64%, Al2O3 16.98%, F 12.37%, ZnO 7.21%, K2O 1.37%, CaO 0.61%, MgO 0.64%, Na2O 0.19%, Fe2O3 1.52%, TiO2 0.47%.

[0072] Figure 2 The XRD results of 4.64 Si 1.36 O 9.68)( ) and the crystallization peaks of zinc spinel (ZnAl2O4) are obvious. The characteristic peaks of zinc spinel (ZnAl2O4) are enhanced at 2θ = 31.26°, 37.01°, and 59.51°.

[0073] As Figure 4 shown, the coal gangue solid waste microcrystalline material prepared in this example has good alkali resistance, and the weight loss rate of alkali resistance (NaOH, 10wt%) is 0.45%.

[0074] In summary, the microcrystalline material prepared in Example 3 has better alkali resistance, and the weight loss rate of alkali resistance (NaOH, 10 wt%) is 0.45%. However, compared with the microcrystalline material in Example 1, the weight loss rate of alkali resistance (NaOH, 10 wt%) is 0.47%, and the difference is not significant. And compared with Example 1 (the number of ZnO parts is 4.67), the cost of Example 3 (the number of ZnO parts is 7) increases. Therefore, for the alkali-resistant coal gangue solid waste microcrystalline material of the present invention, with the change of the amount of the main raw material coal gangue (40 - 70 parts), it is preferably to add 2 - 8 parts of zinc oxide, more preferably in the range of 4 - 5 parts, and most preferably the mass ratio of coal gangue to zinc oxide is 50:(4 - 5).

[0075] Different from the prior art, the present invention provides an alkali-resistant coal gangue solid waste microcrystalline material for ocean engineering and a preparation method thereof. The composition of the microcrystalline material includes coal gangue solid waste and auxiliary chemical raw materials. By weight, the basic glass raw materials of the coal gangue solid waste microcrystalline material include: 40 - 70 parts of coal gangue, 20 - 40 parts of silica sand, 10 - 20 parts of calcium fluoride, 2 - 8 parts of zinc oxide, and 1 - 6 parts of alumina. The preparation method of the present invention first mixes the raw materials evenly, then prepares the basic glass through high-temperature melting, forming, and annealing, and then prepares the coal gangue solid waste microcrystalline material through crystallization treatment, realizing the reuse of coal gangue solid waste with high utilization rate. Moreover, the prepared coal gangue solid waste microcrystalline material has excellent alkali resistance, and the weight loss rate of the optimal group for alkali resistance (NaOH, 10 wt%) is 0.45%, and it is expected to be used in ocean engineering materials. The present invention provides a reference for solving problems such as resource waste and environmental pollution caused by the accumulation of coal gangue.

[0076] The specific embodiments of the present invention described above do not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and deformations made according to the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An alkaline-resistant gangue solid waste microcrystalline material for ocean engineering, characterized in that, The basic glass composition of the coal gangue solid waste microcrystalline material is composed of the following components by weight: 50 parts of coal gangue, 25-35 parts of silica sand, 12-18 parts of calcium fluoride, 4-5 parts of zinc oxide, and 3-4 parts of aluminum oxide; The alkali-resistant weight loss rate of the coal gangue solid waste microcrystalline material is less than 0.51%; the grain size of the coal gangue solid waste microcrystalline material is 20 to 200 nm, the main crystal phase is mullite with an average grain size of 150 to 200 nm, and the secondary crystal phase is zinc spinel with an average grain size of 20 to 50 nm. Both zinc spinel and mullite are spherical and grow in an interlaced manner to form a dense crystal structure.

2. The alkaline-resistant gangue solid waste microcrystalline material for ocean engineering according to claim 1, characterized in that, Calculated by weight percentage, except for fluorine, the components of the coal gangue solid waste microcrystalline material converted into oxides are: SiO2 50-65%, Al2O3 11-20%, F 5.5-14%, ZnO2-8%, K2O 0.5-3%, CaO 0.5-2%, MgO 0.5-2%, Na2O 0-0.5%, Fe2O3 0.5-2%, and TiO2 0-1%.

3. The preparation method of the alkaline-resistant gangue solid waste microcrystalline material for ocean engineering according to any one of claims 1-2, characterized in that, The steps include: (1) Weighing the raw materials of each component of the basic glass and mixing them evenly to form a batch material; (2) The batch materials are melted, formed and annealed at high temperature to obtain the basic glass; (3) The basic glass is crystallized to obtain coal gangue solid waste microcrystalline material.

4. The preparation method of the alkaline-resistant coal gangue solid waste microcrystalline material for ocean engineering according to claim 3, characterized in that In step (2), the high temperature melting temperature is 1400-1550° C., and the high temperature melting time is 2-4 hours.

5. The preparation method of the alkaline-resistant gangue solid waste microcrystalline material for ocean engineering according to claim 3, wherein In step (2), the annealing temperature is 500-650° C. and the annealing time is 2-4 hours.

6. The preparation method of the alkaline-resistant gangue solid waste microcrystalline material for ocean engineering according to claim 3, characterized in that, In step (3), the temperature of the crystallization treatment is 950-1150° C. and the time of the crystallization treatment is 1-3 hours.

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