Production and performance of dense corundum refractories

Conclusions The production technology was developed and production was launched of dense superduty corundum refractories with mullite—corundum binder. The products proved to be highly durable in the lining of a channel type induction furnace at the Volga Automobile Plant.The refractories are used also for the masonry of the roof of the high-temperature glass furnaces used in the production of glass fiber and are suitable as lining material for in-vacuo steel refining installations and other high-temperature heat-using equipment.Deceased.Translated from Ogneupory, No. 7, pp. 17–18, July, 1978.     

The design of sealing devices for thermo-plasticised stretching of fibres in saturated steam

Conclusions By using an approximate design method for multi-chamber sealing head devices for high-temperature plasticised stretching of fibres, it is possible to establish optimum parameters for the sealing heads (number of chambers and diameter of apertures) so as to ensure a minimum and economically acceptable amount of steam leakage.All-Union Synthetic Fibre Research Institute (VNIIV). Translated from Khimicheskie Volokna, No. 3, pp. 52–53, May–June, 1969.     

Cement-free spinel-based refractory materials

Channel induction furnaces can operate at temperatures as high as 2000 °C, which requires the use of high-temperature refractory materials resistant to corrosion. CaO, a conventional component of the corundum-containing refractory castables, produces a degrading effect on high-temperature properties; for this reason, low-and ultralow cement materials fail to meet the needed requirements. Therefore a cement-free refractory of the DALCAST series in the Al₂O₃-MgO binary system based on an Al₂O₃ fully hydratable binder has been developed. Physical properties (strength and hardening behavior) of a standard low-cement castable and a newly developed product based on the results of their practical use in channel induction furnaces are compared and discussed. __________ Translated from Novye Ogneupory, No. 6, pp. 95–98, June, 2005.     

High-Temperature Ceramic Welding: A New Solution To The Problem Of Maintenance Of Refractory Linings

Running repair of industrial furnaces is an important problem solved successfully within the framework of conversion of the defense industry of Russia. The Soyuz Federal Center of Binary Technologies possesses a scientific and materials base for high-temperature ceramic welding (HTCW) as an effective technology for repairing refractory linings. The principles of the HTCW method and its advantages, effect, and prospects are presented.     

A NEW TYPE HIGH TEMPERATURE FUSION FURNACE1

The limitations of carbon, gas, and electric furnaces for high-temperature fusion are discussed. The new oxyacetylene furnace controls the atmosphere in contact with the test cones, protects furnace parts, and insures uniform conditions throughout the furnace.     

APPLICATION OF REPLICA TECHNIQUES TO THE STUDY OF CERAMIC SURFACES WITH THE OPTICAL MICROSCOPE*

A method of preparing transparent replicas of ceramic surfaces for study with the optical microscope is described. Photomicrographs and projection prints of surface details which are difficult to analyze microscopically by direct methods of observation are presented. The surface-replica material used will penetrate openings as small as the limit of resolving power of the ordinary light microscope and can be studied effectively by (1) direct observation by transmitted light in a microscope having the simplest available optical system, (2) used as a transparency and projected on a screen, and (3) placed in a photographic enlarger and used as a negative to produce direct projection photographic prints. The method is particularly useful when duplicate samples of the same specimen are required, when the specimen cannot be destroyed by grinding or cutting, or when reflected light from a surface destroys contrast in detail.     

High-Temperature Heat-Insulating Materials Based on Vermiculite

The production technology and composition of high-temperature heat-insulating materials based on vermiculite have been developed, as applied to the conditions of the Borovichi Refractory Works. Using these materials makes it possible to lower material consumption in thermal machinery, reduce inefficient heat losses, and decrease by 10 – 15 times the total fuel consumption in continuous furnaces and by more than 45% in batch furnaces.     

Choice of regime parameters of the process of heat treatment of waste- water sediments

A review of the main features that determine the choice of techniques of high-temperature treatment of waste-water sediments formed, for example, in refractory enterprises and often combined with sewage water is presented. The physicochemical compositions of the dried sediments are analyzed. The special features of the chemical composition of ash of mechanically dehydrated sediment fired in furnaces with a fluidized bed are presented, and the concentration of harmful substances in the worked-out heating agent is analyzed. It is shown that the parameters of high-temperature treatment of waste-water sediments are chosen with allowance for the composition of the precipitates arriving for treatment.     

Outgassing of high temperature-resistant organic polymeric materials

Four polymeric materials, polyphenylene oxide, polyquinoline, acetylene substituted polyimide, and polybenzimidazole, reported to possess high-temperature resistance, were investigated in order. to determine their outgassing characteristics as related to their suitability for high temperature applications in confined structures. The materials were sequentially exposed to 150, 250 and 450°C for 3 h periods and the types and amounts of their outgassed products were determined. The amounts of outgassed- products were small from polyquinoline, acetylene substituted polyimide, and polybenzimidazole. It was concluded that those materials would be suitable for use in applications where high-temperature resistance (up to 450°C) is required, providing that normal ventilation is available. The quantity of outgassed products from polyphenylene oxide was too great to consider that material suitable for shipboard or other confined structure applications requiring high-temperature resistance.     

Decreasing the waste in metal-heating processes

Results of laboratory development and industrial application of general-purpose coatings for the bricklining of heating furnaces are presented. On the basis of the operating characteristics of the coatings, the effectiveness of their use in furnaces is estimated. The best type of coating, IVAKS-2, is selected, which gives a decrease in the fuel consumption in a soaking pit by 10% and lowers the amount of effluents of nitrogen oxides and carbon oxide by 27% and 20%, respectively, thus improving the waste indices of the processes of metal heating. The IVAKS-2 coating is recommended for wide use in high-temperature heating furnaces of metallurgical and mechanical engineering enterprises. Translated from Ogneupory, No. 4, pp. 19 – 22, April, 1994.     

Highly refractory unfired products with a magnesium-phosphate bond

Conclusions In laboratory conditions compositions were tested for making (by the semi-dry method) refractory articles based on fused magnesite with a bond made from magnesium monosubstituted phosphate.These unfired articles have high strength and spalling resistance.The properties of the developed unfired bodies made from fused magnesia can be recommended primarily for making highly refractory ramming linings and articles (including heat-resistant tubes) for high-temperature furnaces of the laboratory type.     

The Effect of Reducing and Oxidizing Gases and Molten Slag and Alkalis on the Properties and Resistance of Nitride-Based Refractory Materials

Silicon carbide refractory materials and specimens of silicon nitride and silicon oxynitride are tested under high-temperature attack from reducing (H₂ and CO) and oxidizing gases (O₂, air) and from molten slag, alkalis, and iron. It is shown that nitride-based refractory materials are prone to change their properties, structure, and resistance when exposed to molten slag, iron, and alkalis. Silicon oxynitride and silicon nitride resist attack from carbon monoxide and alkali and provide protection to silicon carbide used as the refractory lining for blast furnaces.     

Experience with the work of rotary furnaces at the Bogdanovich Refractories Plant

Conclusions The measures accomplished aimed at improving the work of the furnaces at the Bogdanovich Refractory plant justify themselves in practice and can be recommended for introduction in other concerns.Experience with the operation of rotary furnaces showed that the presence in the furnaces of an extended zone in the high-temperature section should be considered as undesirable, especially when firing clays of variable composition, It is necessary to study the matter of using an extended zone in the hightemperature zone from 700–to 1000°C, that is, in the zone where organic impurities are oxidized, which, other conditions being equal, can contribute to an increase in the density of the grog.As a result of variations in the properties and compositions of the clays, calcination of them in rotary furnaces is characterized by periodic disturbances in the working cycle, owing to which it is not possible to obtain grog uniform in quality. It is necessary to carry out further studies aimed at improving grog quality.Tests carried out on the firing of Arkalyksk raw materials showed us that it is possible to obtain highly dense grog in rotary furnaces. To reduce the content of fractions finer than 2 mm the fine fractions of clay should be sieved out and calcined after briquetting.     

VARIOUS METHODS OF TOOLING CONTINUOUS ENAMELING FURNACES1

The importance of adequate firing tools for handling the various shapes which are enameled in continuous furnaces is discussed. The maximum efficiency of a continuous furnace can only be realized when the conveyer chain is equipped with tools which permit uniform loading throughout its entire length with enough ware to utilize fully the heating capacity of the furnace. Materials and principles of design are considered and specific tools and racks suitable for various sheet-iron and cast-iron parts are illustrated.     

Checker blocks for blast-furnace stoves

Conclusions A design was developed and introduced into production for a mold suitable for making perforated blocks for the checkers of blast furnaces by the semidry method on a redesigned SM-143 press. It was demonstrated in principle that it is possible to use the semidry method for pressing chamotte perforated blocks grades VShA and VShB, using a technology employed for manufacturing stove refractories for blast furnaces.The production technology should be tightened up if the products are to have stable strength, porosity, and after-contraction factors (product grade VShA). The technical requirements for the finished products in terms of spalling resistance require reexamining to take into account the shape of the specimens.Translated from Ogneupory, No. 4, pp. 6–9, April, 1971.     

Speeding up the firing of silica in gas-chamber furnaces

Conclusions Speeding up the firing of silica products in gas-chamber furnaces does not lead to an increase in loss. It is most desirable to accelerate the firing of silica in gas-chamber furnaces with supplementary gas feed into the second preheat chamber in a period of 10–18 h. Under these conditions it is necessary to reduce the gas feed into the chamber working on the high-temperature schedule.     

Operation of high-temperature shaft furnaces with layerwise firing

The thermal operation of high-temperature shaft furnaces with layerwise firing has been investigated. Fundamental drawbacks of this firing method are described, which prevent it from being recommended for industrial use, since it does not meet modern ecological and power-saving requirements. Translated from Ogneupory, No. 7, pp. 28–30, May, 1994.     

Numerical Simulation of Transfer and Reaction Processes in Ethylene Furnaces

The complex transfer and reaction processes happened in ethylene furnaces were taken into consideration. A comprehensive mathematical model was developed with CFD technique based on the following knowledge: (1) basic transport equations of hydrodynamics, (2) k– turbulence model, (3) cracking reaction kinetic model developed by Wang, (4) presumed probability-density-function model for turbulent diffusion combustion, and (5) discrete ordinates method for radiative heat transfer. The simulation results showed detailed information about flow and temperature fields, heat flux distribution, and concentration distribution. They provided thorough understanding on the basic characteristics of hydrodynamic phenomena and reaction behaviour occurring in industrial ethylene furnaces. Parametric studies were carried out to investigate quantitatively the influence of burner staging, tube diameter and spacing on operation performance of ethylene furnaces. The comprehensive mathematical model and computational scheme presented here can be used as a tool for the design of ethylene furnaces.     

Utilization of energy in recuperative counterflow furnaces

Conclusions Recuperative counterflow furnaces are based on a thermotechnically ideal scheme of heat exchange and are the most promising systems for firing ceramic materials on a large scale. The thermodynamic quality of such furnaces is governed by their exergetic characteristics, which are based on the first and second laws of thermodynamics.The formation of an isothermal area of sintering in a recuperative counterflow furnace is possible on account of a small fraction of the energy of the fuel, which decreases with rise in the firing temperature. Improvement of the energy relations of the furnace and the quality of firing of the material involves optimization of the sintering parameters and reduction of the resultant heat fluxes in the high-temperature holding section.Translated from Ogneupory, No. 2, pp. 24–30, February, 1980.     

基于模糊多属性决策的高温陶瓷过滤器保温层选材设计研究

以合理化选择高温陶瓷过滤器保温层为目的,选取适合作为高温陶瓷过滤器保温 层的不同材料,通过递阶质量屋法对材料属性和设计要求进行研究计算,得到关于整体顾客满 意度的材料属性综合权重值,用作下一步材料选择的基础。运用模糊多属性决策计算备选材料 与最优材料的贴合度,结合关于整体顾客满意度的材料属性综合权重值,建立最终适合陶瓷过 滤器保温层的材料组合满意度排序,以确定适合高温陶瓷过滤器保温层的最优材料,为陶瓷膜 组件的材料选择与设计提供参考。