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CERAMICS FROM REFRACTORY OXIDESiReviewed byl~. V. Degtyareva UDC 666.762(049).3)The new high-temperature processes and installations in which use is made of various media, the accelerated process in existing equipment, and developments in nuclear engineering and energetics call for an ever expanding use of materials based on refractory oxides. The most useful of these oxides are A120~, SiO2, MgO, CaO, Cr203, and ZrO 2. Mutlite, spinel, zircon, and forsterite are also promising materials in this context. $ Soviet production of oxide refractories and superduty ceramics from oxide compounds has not yet reached an adequate level of development. Products of corundum and zircon ceramics are also being produced merely in experimental batches.In other countries corundum refractories and ceramics are used extensively in ferrous metallurgy for the lining of blast furnace stacks and runners, of the suction and discharge pipes of in-vacuo steel refining equipment, of mixers for cast iron storage, furnaces for calcining anthracite, plates for the slide gates of steelcasting ladles, etc. Refractory ceramics processed from alumina, calcium, and zirconium oxides are very promising materials for the lining of magnetohydrodynamic equipment, acceleration tubes, sensors for measuring the acidity of steel, etc.All these facts stimulated the interest of research workers in the development of a technology and the study of the properties of refractories and sintered ceramics based on refractory oxides~ the volume of information in this field has grown significantly in recent years. The department of the chemical technology of ceramics and refractories of the D. L Mendeleev Institute of Chemical Technology in Moscow is one of the centers for the development of technologies, the preparation of the composition, and the study of the properties of ceramics and refractories based on refractory oxides. The book reviewed here is a monograph by the staff of that department in which they generalize the results of their research in this field and it is therefore of considerable importance.In Chap. 1 the authors describe the principles of the production of ceramics from refractory oxides and examine not only the scientific aspects (the kinetics of the grinding of the materials, the processes of the chemical precipitation of the compositions, the mechanism of sintering, and the kinetics of the consolidation of the refractory oxides and their compotmds) but also the technological conditions of the heat treatment of the starting material and of the grinding process (including questions relating to the equipment to be used), the methods of introducing additives, the methods of forming the product including vibromolding and isostatic molding, and the characteristics of the sintering process. This chapter also contains an interesting review of the basic properties of ceramics processed from pure oxides in which comparative data are given for the cold-crushing strength, elastic modulus, thermal expansion, thermal conductivity, thermal-shock resistance, cr...

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The book represents a continuation of the monograph "Basic Refractories ' by the same authors [1] and is characterized by the high scientific --technical level of its material, specific nature ann clarity of all conclusions, and the completeness of its reference section.The book has two chapters. The value of Chap. 1 consists in the fact that it represents a summary of the results of all important research projects and of industrial experience in the production of forsterite refractories, The book outlines the extensive scope for the production of magnesiosilicate refractories from various raw materials.Forsterite refractories still occupy a modest place and up to now re[atively few applications have been identified in which forsterite-containing products would be preferred from the standpoint of cost effectiveness to other types of refractories (e.g., forsterite nozzles in place of magnesite types [2]).Such a position cannot be considered normal. The refractoriness of dunite without additives is 1750~ (p. 14), while that of chamotte brick even of grade ShA is 1730~ . In certain new metallurgical processes, the steel is not permitted to come in contact with refractories which contain free silica. In view of the high refractoriness of magnesiosilicate products compared with that of chamotte refractories and because of the absence of free silica in the former, it is to be expected that the part played by forsterite refractories will increase in the near future. The development of a technology for forsterite-containing products based on natural raw materials without or with only a small amount of an additive (e.g., up to 5% fired magnesite) and an extension of the area of utilization of magnesiosilicate refractories in place of chamotte or magnesia types are therefore urgent problems.The book reviewed here can certainly be of help in the solution of these problems but unfortunately it does not mention the use of the natural magnesium silicates which contain no free silica and are used in the production of the heat insulation inserts used in the casting of killed steel.Chapter 2 deals with spinel and spinM-containing refractories. The subject matter is based mainly on the authors' own research (42 of the 123 literature references are by these two authors).Descriptions are given of the starting materials, the preparation of the alumina and magnesia components, and the synthesis and sintering of spinel together with descriptions of the technology of various spinel and spinel-containing refractories and of the properties of the products. All this is presented in detail on the basis of factual material.The book contains a description of two methods of producing pure spinel, viz., by sintering and by fusion. Depending on the method of producing the spinel, the properties of spinel-containing refractories, which are assessed by the authors mainly in terms of their porosity, are in one case (p. 11.6) better when using sintered spinel and in another (p. 119) when using fused spinel.A description is given of the use of magne...