The results of investigations of crystal glass materials based on cordierite glass containing TiO 2 as a catalyst are presented. It is established that the synthesis of glass under exposure to a concentrated radiant flux has the same effect on crystallization processes as increasing the catalyst content. The optimal composition and conditions for obtaining sintered sitals from glass powder are determined.There are a large number of works on the particularities of the crystallization of MgO -Al 2 O 3 -SiO 2 glasses. These works devote special attention to the crystallization of glass with cordierite composition, since it is precisely this type of glass that forms the base for crystal glass materials with the optimal combination of dielectric and thermomechanical properties. Cordierite crystallizes via the formation of a number of intermediate phases whose temperature intervals of formation and stability depend on a number of factors, including the conditions under which the glasses are synthesized. This article presents the results of investigations of the character of the crystallization of glass with cordierite composition obtained under exposure to a concentrated radiant flux.The initial components were magnesium and aluminum oxides as well as quartz-kaolinite-pyrophyllitic rock (SiO 2 source). Chemical analysis showed this mineral to contain the following (% 2 ): 77.64 SiO 2 . 17.43 Al 2 O 3 , 0.39 MgO, and trace impurities (Fe 2 O 3 , Na 2 O, K 2 O).The glasses were synthesized in a solar furnace as well as in a simulator where 10-kW xenon lamps served as the source of heat. The fused glass was poured into water. This method of quenching the melt made it possible to obtain brittle granules which could be easily milled.A DRON-UM1 diffractometer was used for x-ray phase analysis and a Q-1500 D derivatograph differential-thermal analysis. Glass powders with different particle size (from 1 -5 to 80 mm) as well as 2 -3 mm fragments of granules were analyzed.Previous investigations of glasses with stoichiometric cordierite composition without catalysts [1,2] showed that the crystallization process can be represented in terms of the following scheme:Since glass cannot undergo bulk crystallization without a catalyst, investigations were performed to determine the influence of TiO 2 as a catalyst on the crystallization process for glass with cordierite composition. The catalyst was introduced into the stoichiometric glass in amounts 2 -12% (above 100%). It was determined that when TiO 2 was introduced during the melting process the color of the castings ranged from straw-colored (2% TiO 2 ) to black (12% TiO 2 ), which could indicate an increase of the Ti 3+ content in the glass.The introduction of 2% TiO 2 had no appreciable effect on the crystallization rate of the glass. The main crystalline phase was a cordierite. As the amount of TiO 2 increased, the crystallization process changed sharply. The crystallization of m cordierite was already activated during sintering of
Results are presented from an analysis of the motion of gas flows created by fuel-burning devices in existing electric-arc steelmaking furnaces and recommendations are made on how to efficiently arrange this equipment in the furnace. Controlled annular motion of the aerodynamic flows in the part of the working space between the furnace wall and the electrodes increases convective heat transfer to the cold solid charge, forms a reliable and uniform slag crust on the water-cooled wall, and alleviates the deposition of process dust on the electrodes. A numerical study is performed using the SolidWorks Flow Simulation program and boundary conditions that reflect the actual operating conditions in the furnaces.Improving the gas dynamics in the working space of modern electric-arc steelmaking furnaces (EAFs) to provide for efficient heat transfer and rapid, uniform heating of the charge over the entire surface of the bath is a technically complex problem. Experience in the operation of EAFs shows that optimizing the arrangement of the fuel-combustion devices (FCDs) is an empirical undertaking. Any changes that need to be made to the locations of the FCDs have already been incorporated into the design of new prototypes, and the expediency of those changes are evaluated based on the results obtained from the furnaces' operation. The potential for putting new ideas to practical use on existing furnaces is always limited, and conducting experimental studies requires large amounts of time to prepare for and coordinate the necessary operations. In the investigation discussed in this article, the above problem was addressed through computer modeling and engineering analysis.We used a 3D model of the furnace (Fig. 1) that was previously constructed in the chart-and-graphics editor of the system KOMPAS-3D and then imported into the supplemental software of the program SolidWorks Flow Simulation to calculate the gas dynamics of the furnace's working space.Models differing in the locations of the FCDs were examined. In the first model, FCD location was chosen in accordance with a design developed by the company "Danieli" (variant A). In the second model, the FCDs were positioned in accordance with the recommendations made in [1] based on the results of a graphical analysis of the propagation of
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