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Monolithic linings, produced by casting with silica refractory cement, have found wide use in steel teeming ladles [1][2][3][4][5][6][7][8][9][10]. The simplicity of the process, the high level of mechanization, and the possibility of increasing the total life of the lining to 100 and more heats are an indication of the promise of this method of preparation.The silica refractory cement is prepared using as the base type ZKM-97 high quality crystalline quartzites with a silica content of not less than 97%* according to Technical Specification 14-8-92-74. The wide use of poured monolithic linings is responsible for a significant shortage of quartzite powders, and therefore the search for reserves for broadening their production is a pressing problem. The authors of this article have developed a method of producing quartzite powders from the quartzite wastes of the crushing and separation plant of First Ural Dinas Plant.The method of production of dinas refractories at First Ural Dinas Plant includes beneficiation of the quartzites at the crushing and separation plant for the purpose of removal of the clay inclusions. Beneficiation of quartzite for the production of dinas is done by washing it with water on screens. The slurry obtained, which contains wastes of the finer than 5 mm fraction, is directed from the crushing and separation plant to the settling tanks. The silica content in the wastes varies within significant limits and decreases with an increase in the fineness of the quartzite (Table 1). This is caused by the lower hardness of the clay inclusions and the schists in comparison with quartzite and therefore in crushing they are converted into fine fractions in greater quantity. In connection with this, for the purpose ofbeneficiating the wastes it is desirable to subject them to additional washing and separation. Removal of the finer than 0.5 mm fraction, the quantity of which is 25-30% in the wastes, makes it possible to increase the silica content in the wastes to 97.3% and to place them in the class of conditioned quartzites.To determine the possibility of use of quartzites directly from the settling tanks, the distribution of the quartzites in the settling tank was studied and their quantitative determination is given in Table 2. In the settling tanks the quartzite is distributed nonuniformly by silica content. The purest is located in the direct vicinity of the entry pipe. * Here and subsequently wt. % is given. --97,3

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At present magnesite-carbon products are being increasingly used industrially; they include essentially the following classifications: periclase-carbon, periclase-lime-carbon, carbon-periclase, spinel-carbon, forsterite-carbon, periclase-zircon-carbon, etc. [I]. The characteristic properties of these products are high metal and slag resistance, high thermal conductivity, low porosity, the absence of scaling in service, and as a result, an increased wear resistance in the linings of furnaces.The Eastern Institute of Refractories together with the Magnezit Combine and the OrskoKhalilovsk Metallurgical Combine (OKMC) have developed and tested a technology for the production of periclase-carbon articles grade PU-I16 using sintered periclase powders. This technology can also be used in factories making magnesia refractories: Panteleimonovsk, Nikitovsk, Zaporozhe, etc.The starting materials consisted of sintered periclase powder fractions 3-1 mm and minus 0,06 mm, Taiginsk or Zaval'evsk graphite, organic bond, and an additive in the form of antioxidant (Table i).In laboratory conditions these materials were mixed with the organic bond and the antioxidant, pressed into specimens of diameter and height 50 mm, dried at 120-170~ (24 h), and fired in an air atmosphere at 1600~ with a soak of 5 h.With increase in graphite content after firing there are increases in the gas permeability, mass loss, and the degree of combustion of carbon from the periclase-carbon specimens; the magnetic susceptibility of the articles is uniformly reduced (Fig. i). The gas permeability of the specimens is most sharply increased with a graphite content of more than 15%. After firing, the specimens with this content of graphite have a surface burnt-out zone 1-2 mm thick under which the graphite does not burn out from the specimens (Fig. 2).An experimental batch of periclase carbon articles grade PU-II6 containing 15% graphite was prepared at the Magnezit Combine.The components were mixed in a runner mill, and the articles were shaped on the PR-7 press at 130-150 MPa. The body weight of a single article was 13.6 kg, the dimensions 386 • 154 x 85 • 75 mm. In developing the "press-packet" technology some of the articles without drying were blocked into packets, and the remainder were dried at 180~ in tunnel driers (I day) and also packaged. The properties of the goods are shown in Table 2.The periclase-carbon goods before drying and after drying are quite strong, and have a low porosity. During drying about 3.4% of the volatiles are distilled off, and there is an increase in the magnetic susceptibility of the goods. The refractoriness under load is above 1700~Complex thermal analysis shows that at 250-300~ the organic bond starts | burn in the articles and at 580~ the graphite starts to burn (Fig. 3a). After firing at i~ 0~ (soaking for 5 h) in air the degree of combustion of the carbon is 42.1%, the gas permeability i0.2 ~m 2, the specific magnetic susceptibility 32.7.10 -6 cm3/g. The periclase-carbon articles were used to build the walls of two 10...