SU927784A1 - Batch for producing synthetic mullite - Google Patents

Description

The invention relates to ceramic production and can be used in foundry, chemical and other industries. The known charge G11 for the production of synthetic mullite, which consists of melted kaolin, contains M (0 ton of technical aluminum oxide (grain fineness: 55 microns) and (by weight of the initial mass) mineralizers as a mixture of at least two salts, such as fluoride and aluminum chloride, phosphate or aluminum vanadate or aluminum sulfate, as well as 1-2 ammonium salts listed.The resulting synthetic mullite contains Al (TiOn 68-77, FerjOoi l, 5, mullite 70-80. The disadvantages of the mixture are the use. scarce and expensive cheese pb - alumina, high content of iron oxides in the final product, as well as significant economic costs for kaolin melting and grinding the raw material mixture. All this leads to the complication of technology and the cost of the final product. The closest to the invention is the mixture for producing synthetic mullite containing fused ash concentrate, hydrothermally treated slags of aluminum production and a mineralizer, which can be used as aluminum vanadate, in the following ratio UK The main components, weight .: Ash concentrate W, 3, 1 Slag of aluminum production, 7 Mineralizer 2 - k The disadvantages of the known charge are the need to granulate non-ductile material (TPP sol), use of an expensive aluminophosphate bond, significant energy costs for obtaining sol concentrate by melting, the need to use additional equipment to obtain a sol concentrate. All this complicates the process and increases the cost of the final product. The purpose of the invention is to increase the density, strength and temperature of deformation under load while reducing energy costs. The goal is achieved by the fact that the charge, including the alumina-containing component and aluminum vanadate, as the alumina-containing component contains a spent petrochemical production catalyst treated with metal chloride and additionally kaolin in the following ratios, wt.%: Treated with chloride. metal spent catalyst petrochemical production Vanadat aluminum Kaolin. The spent petrochemical catalyst is a finely dispersed green powder with a high specific surface (20-30) and is characterized by the following chemical composition, wt% SiO8-8.8; A1.10373, 55; Re, 10, up to 0.80; FeO up to 1.24 j j1 3, 6 15.23; CaO 0.35-1.51, MDO up to 1.20-, KqO Na, 0 0.08-1, 11. To obtain synthetic mullite from the mixture of the proposed composition, the spent petrochemical production catalyst is treated with metal chloride, such as NaCl, MgCIn, A1SC, followed by drying the mixture in order to get rid of iron impurities, since they impair the physical and technical properties of the product obtained. The high specific surface area of the spent catalyst in the petrochemical industry provides a high reactivity of the charge, accelerates the formation of mullite, which leads to the formation of a fine-crystalline structure of the finished products, and hence an increase in their density and compressive strength. In the process of roasting at 1580-1–50 ° C, contained in the spent catalyst of the petrochemical industry, they interact with kaolin to form solid solutions of mullite and corundum, which improve the physical and technical properties (increase the density and compressive strength) of the resulting products. The content in the charge of the mineralizer vanadate aluminum accelerates the synthesis of mullite by preparing in the liquid phase the groups fSI04, AtO.jT GAU in ratios approximating their content in mullite. They also change the size and specific surface of mullite crystals. The amount of spent petrochemical catalyst processed by the metal chloride less than 7 is not enough for synthesis, as the content of AlpOpi decreases, an excess of silica is created, which impairs the physical and physical characteristics of the final product. The content of the spent catalyst of the petrochemical industry treated with metal chloride over 78% leads to an increase in the content which increases the formation of corundum while reducing the mullite in the finished product. The content of kaolin 19 leads to the predominance of solid corundum solution in the finished product. The kaolin content of more than 231 samples is the appearance of crystalline secondary tumors with the release of quartz, which reduces the physical and technical properties of the resulting product. Reducing the amount of mineralization-. torus in charge of 1 2% leads to a decrease in the rate of synthesis of mullite. An increase in the mineralizer content k% leads to the formation of side low-temperature compounds. To obtain synthetic mullite under industrial conditions, the spent petrochemical production catalyst previously treated with metal chloride is mixed with kaolin suspension, after which the mixture obtained is dried using spray dryers to a residual moisture content of not more than 2.5%. From spray drying, the obtained: powdered powder with a grain size of Q, k0, 7 mm is fed to the pressing of products, which are then fed to roasting, followed by cooling in the disconnected kiln.

To obtain synthetic mullite, three batches are prepared with a different ratio of components. Aqueous suspensions are prepared from spent petrochemical catalyst and kaolin, then the spent catalyst slurry is treated with aluminum chloride and then mixed with kaolin slurry. The resulting mixture is stirred in a propeller mixer and dried in an electric oven to a residual moisture

more than 2.5%. The dried mixture is rubbed through a 0.63 micron sieve together with the added aluminum. From the mixture thus obtained, the samples are pressed under a pressure of 500 kgf / cm in the form of discs with a diameter of 1 mm and a thickness of 3 mm, which, after being kept in a desiccator for 24 hours, are burned in an electric furnace with subsequent cooling in a switched off furnace.

The composition of the charge and physico-mechanical properties of synthetic mullite are shown in the table.

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Claims (2)

g-- . 9 As can be seen from the table, the developed blend for producing synthetic mullite based on a chloride-treated metal catalyst in petrochemical production allows to obtain a final product with an elevated temperature deformation under load by 20-50 ° C without additional shrinkage. Moreover, the use of the proposed blend allows get the final product (synthetic mullite) with significantly lower energy costs: save electricity 1000-1350 KW / H, heat 1000 1500 kcal, graphite electrode s 100-150 kg per 1 ton of synthetic mold. Claims of the invention for producing synthetic mullite, including an alumina-containing component and aluminum vanadate, characterized in that, in order to increase the density, strength and temperature of deformation under load while reducing energy costs, the spent catalyst treated with metal chloride is used as an alumina-containing component petrochemical production and additionally kaolin in the following ratio of the above components, mas: Treated with metal chloride otrab otanat catalyst petrochemical- production Vanadat aluminum 2Kaolin19-23 Sources of information taken into account during the examination 1.Patent NDP No. 6231, cl. From Ok To 35/10, 1971. 2. USSR author's certificate №, cl. C 0 To 35/10, 1973 (prototype).