Silicon carbide refractory materials and specimens of silicon nitride and silicon oxynitride are tested under high-temperature attack from reducing (H 2 and CO) and oxidizing gases (O 2 , 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.

The optimum compositions of oxygen-free mixtures for manufacture of nitride-based refractory bonds are reported. A technology for manufacturing chamotte refractory materials with a compound nitride-based bond is developed. The newly designed materials exhibit improved physicomechanical properties and enhanced durability against attack by alkalis and molten slag.

It is shown that the partial pressure of oxygen and thermocycling in variable gas media are the main factors characterizing the thermal stability of aluminosilicate refractories. The obtained functional dependences of the variation of the properties of the refractories are described by equations.

Properties of aluminosilicate, silicon carbide, and carbon refractories and mixtures used for lining blast furnaces and recommended for the future are presented. Recommendations are given for changing the design of some lining zones with the aim of increasing their endurance and reliability in service.

The production of mullite from natural aluminosilicate materials and oxides is described. The characteristics of mullite synthesized under different conditions in gas media by sintering and melting are presented. It is shown that the morphological characteristics of mullite are an important factor for evaluating the quality of refractories. Tubular mullite is shown to be the most efficient reinforcing component, determining the high strength of refractories operating under high temperatures and loads for a long time.

On November 1–3, 1995, an international scientific and engineering conference “Development of Engineering Chemistry in Ukraine” took place in Kharkov. The reports of the plenary meeting were devoted to the main directions of progress in the chemical industry and to the colloidal chemistry of building materials. The participants worked in nine sections. The recommendations developed by the section “Superhard materials and refractories” are presented.

Aluminosilicate pressings in various gas media are investigated. It is shown that the formation of crystalline substances and vitreous phase depends on the gas medium. The importance of investigating the composition of the vitreous phase in order to control its properties and the quality of articles is stressed.

Results of an investigation of the interaction between mullite-containing refractories and nickel nitrate additives under conditions of oxidizing-reducing gas media at 500–1500°C are presented. Mineral-forming processes in firing in a reducing medium and decomposition of newly formed compounds in firing in a medium of hydrogen and carbon oxide are described.

The materials of a scientific and engineering conference conducted on March 26 – 27, 1996, in Kharkov are reviewed. The conference was devoted to the production of new kinds of zirconium, corundum, silicon carbide, mullite, forsterite, and dolomite refractories, ramming and vibrocast mixtures, concretes, and light-weight and fiber materials. The reports concerned the service of refractories in various heating units and some economic and methdological problems.

The interaction of mullite-corundum refractories with iron oxides in an oxidizing medium results in the formation of solid solutions in mullite and corundum. When fired in a reducing medium the solid solutions decompose with disruption of the structure and loosening of the refractory. Repeated heat cycles in different gaseous media lead to a periodic change in the phase composition of the refractory and worsen its quality and hence its stability in service.

Silicon carbide refractories with binders of silicon nitride and silicon oxynitride are compared with dense aluminum silicate refractories. It is shown that silicon carbide refractories possess high stability in aluminum melts and vapors of aluminum chloride, whereas aluminosilicate refractories are severely damaged under these conditions. Silicon carbide refractories with a binder of silicon nitride possess the highest resistance to the effect of the tested aggressive factors and are recommended for operation in aluminum melts and gaseous aluminum chloride media.

Investigations of the technology of mullite-corundum refractories containing silicon carbide and used for linings of transportable mixers are described. It is shown that an addition (10%) of silicon carbide to a mullite-corundum mixture ensures a high slag resistance. Mixers lined with mullite-corundum refractories with silicon carbide have shown high service properties, namely, 720 pourings of cast iron with 5 hot repairs.

The conference at UkrNIIO held on March 14–15, 1995 under the motto “The quality of refractories is a way to power saving and efficiency” was attended by representatives of the Ukrogneupor Concern, research, design, and educational institutions, and refractory and other enterprises of Ukraine and Russia. More than 40 reports were presented on scientific developments, production, and use of refractories in various branches of industry.

The properties of articles from Nicrolite, i.e., casted stone slag or molten slags of ferrochrome production, are investigated. Nicrolite is used to prepare articles for different parts of installations of the coke and by-product industry.

Results of examination of the consumption of power resources at several refractory plants are presented. It is shown that the plants have possibilities for saving considerable amounts of fuel, heat, and power. Examples showing ways to save power are presented.

The synthesis of a combined nitride-containing binder is described. The main parameters for the production of corundum refractories with the combined nitride-containing binder are determined. The refractories have a high resistance to the effect of slag melts.

The technological parameters of the production of silicon carbide refractories with a silicon nitride binder are investigated. An experimental industrial batch of refractories has been produced by the Semiluki Refractory Plant and shipped to the Kaustic Production Association to be used in linings of reactors for the production of aluminum chloride.

Technological investigations on the development of heat-insulation mixtures exhibiting high wearability in linings of tuyere apparatuses of blast furnaces are presented. It is shown that with increase in the firing temperature of specimens of these mixtures from 1000 to 1300°C their strength is improved despite an increase in the porosity, which ensures the requisite technological properties.