Summarized material is presented, characterizing the pore space of refractories, whose analysis makes it possible to make recommendations for controlling production parameters in order to prepare refractories with a desired pore structure. The results obtained are based on known research of the pore space, different pore classifications, and also the authors’ industrial and experimental experience.

This paper continues the presentation of results from observations and studies over many years on lining wear in tunnel furnaces for firing periclase, periclase-spinelide, and periclase-spinel refractories. New wear data are given for basic refractories in the major constructional elements in a high-temperature furnace: in the wall lining and in the burner embrasures. The mechanism has been defined for the flaking in wall lining elements, and some preliminary conclusions are confirmed from earlier studies that provided the basis for recommendations on upgrading wall lining in tunnel furnaces at the Magnesite Group Corporation.

With the aim of selecting possibilities for use in industry of chromite ores from different deposits in order to produce periclase-chromite refractories these ores are studied by optical and electron microscopy, and also chemical and differential thermal analysis: Indian, Iranian, South African and Turkish. High temperature changes that occur within them are described. Microstructural features for periclase-chromite refractories based on these chromite ores and the interconnection of indices are revealed that make it possible to recommend an ore for a specific application.

A brick mortar (the chromite-periclase filler, CPF) for the hot-face lining of rotary kilns for calcination of magnesite and its mixtures has been developed and tested. The CPF is based on a periclase-chromite mixture with the addition of aluminum and ferrophosphorus. The use of CPF makes it possible to increase the lining endurance of 90 and 170-meter rotary kilns by a factor of 2.5 and 1.5, respectively.

A technology for fabrication of corundum-based carbon-containing refractories with a ceramic bond has been developed and put in service under industrial conditions at the Kombinat Magnezit JSC. The microstructure, preparation technique, and mechanisms of wear are considered. The physical, ceramic, and thermal properties of the newly developed material are discussed and compared to those of conventional refractory materials. The unique and advantageous properties of this material are emphasized.

A polymineral component of the magnesite ore of provenance from the Satkinskoe deposit — the so-called carbon-containing matter — is analyzed for composition using advanced techniques. The component has a complex composition, with the prevalence of a magnesian ferrous aluminosilicate, chlorite, in it and, for that reason, may conventionally be termed a carbonaceous chlorite matter (CCM). The CCM, when heat-treated, yield compounds that lower the quality of the final product, which makes it necessary to develop a beneficiation technology for removing CCM from the Satkinskoe magnesite ore. Results of the present study can be used to develop new technologies for recovery and beneficiation of magnesite and its processing into refractory materials.

Some special features of the mineral composition of magnesite from deep horizons of the Satkinskoe group of deposits is considered. Minerals that are paragenetically connected with magnesite and affect substantially the production process and quality of refractory products are described. It is established that the concentration of SiO2 in the magnesites increases regularly with increase in the depth of the horizon. Ways to solve the problem of fabricating quality magnesite for roasting are suggested.

The refractories of the lining of burner embrasures of tunnel kilns are subjected to intense wear in the form of scourings, effects of wall and embrasure deformations, and spalls during service. The service life of the lining of burner embrasures can be increased by raising the quality of the refractories and improving the design of the burners and the operating regime.

Types of and reasons for wear of the wall linings of tunnel kilns are studied. It is established that the aftereffect of plastic deformation and spalling and scouring in the working zones are the most important wear factors. In order to normalize the operation of tunnel kilns, it is recommended to use lining refractories with less than 1.5% SiO2 and less than 8% Cr2O3 in the total mass and melting temperatures exceeding 1700°C and to change the design of the inner layers of the linings.

An all-round investigation of the properties of refractories made from Zabaikal'sk magnesites showed that they can be widely used in very diverse areas of metallurgy, engineering, medicine, perfume production, and other industries.

The possibility of production of PKhP parts to TU 14-8-368-81 from a mixture of combined ground fused Periclase-chromite with the crust has been shown.

The basic picture of wear of unfired PShGB periclase-spinel parts in melting furnaces and cement kilns with different service conditions has been established. Wear of PShGB refractories in arc furnaces occurs primarily by thermal spalling of the working zones.

Mechanical activation leads to partial breakdown of the crystalline structures of refractory materials, conferring a higher reaction state on them. This is manifest as a reduction in the temperature range in which the magnesite and dolomite undergo conversions during heating, and also in the greater degree of exposure of the periclase and chrome concentrate.

Increased wear resistance of a combined lining consisting of acid and basic parts in the sintering zone of rotary kilns for firing of magnesite was established on the basis of chemical and petrographic investigations and visual observations.

The investigation into the possibility of obtaining periclase-spinel refractories of the PShPKh type based on fused materials and hollow KhGSh granules obtained on the “Plazmatron” equipment, showed unsatisfactory sintering of the granules with finely milled bond and, as a result, poor factors for compressed strength and refractoriness- under-load.

The use of refractory batches, in the production of periclase-carbon refractories developed by the Magnezit Combine, with the introduction of complex additives, a liquid constitutent in the form of liganosulfonate of improved quality helps to produce periclase-carbon refractories ensuring a high resistance in the high-wear zones of various furnaces in the metallurgical industries.

Conclusions A technology was developed for periclass-spinel, low-silica chrome-concentrate (SiO2 2 < 3%). As regards the resistance in the walls of the metal zone of circulation vacuum equipment, these refractories are not inferior to PKhP periclase-chromite goods made from fused materials.

The Magnezit Combine has developed bodies for monolithic linings of steel ladles, providing more effective use of starting materials with a simultaneous increase in the resistance of the metallurgical equipment. However, to achieve the advantages it is necessary to redesign the existing production line, especially the mixing and weighing sections.

The most common and characteristic forms of scrap of magnesia parts differing in form, dimensions, and composition are shown. These include deviations of the dimensions from the nominal, breaking off of the corners and edges, nonuniformity, welding together, spots, voids, fire cracks, spalls, and cracks of different origin.