Production of fused periclase from natural raw materials

Conclusions The properties and microstructure of periclase were studied. The influence of the original raw materials on the chemical composition and microstructure of periclase across the zones was established. In any raw material the minimum quantity of periclase impurities is noted in the single-crystal zone, but partial removal of impurities during fusion is not sufficient if the original raw materials do not possess the necessary purity. The use of chemically enriched Tal'sk magnesite improves the properties of periclase and the homogeneity of the block across the zones. It is necessary to carry out systematic research work on the preparation of raw materials and to elucidate the optimum parameters for fusion technology, ensuring improvements in the quality of the periclase.Translated from Ogneupory, No. 7, pp. 5–11, July, 1972.     

Microhardness of fused periclase

Conclusions The microhardness of fused periclase has been studied. It is shown that the microhardness of periclase is significantly affected by defects in the structure, in particular, by the dislocation density and the presence of impurity oxides.When fused periclase is heat-treated at 1000–1400°C which reduces the dislocation density by approximately two orders of magnitude, the microhardness of periclase is decreased. The reduction in the microhardness helps to increase the electrical resistance of the periclase as a result of both a decrease in the dislocation density and also, obviously, of the change in the packing density of the particles if the electrical resistance is measured in tubular electric heaters.The reduction in the microhardness helps to improve the ease of pressing of the refractory articles manufactured using fused periclase.Translated from Ogneupory, No. 4, pp. 10–13, April, 1984.     

Refractories from fused periclase

Conclusions High-grade refractories can be produced from periclase containing at least 97% MgO by preparing a suitable grain size distribution with a vibro-ground component in the powder, molding in stages at high specific pressures (1500–2000 kg/cm²), and firing for 8 h or more at a high temperature (1750°C or higher).Translated from Ogneupory, No. 6, pp. 5–8, June, 1974.     

Possibilities of beneficiation of fused periclase powders

Conclusions The method developed for chemical purification of PPÉ of calcium and silicon oxides makes it possible to decrease the content of the calcium oxide impurity limiting the quality of PPÉ at Refractory Production Union to satisfaction of the requirements for grades 1 and 2 of electrical periclase. The creation of a special area including the production of distilled water in the necessary for production introduction of the method.Translated from Ogneupory, No. 7, pp. 36–40, July, 1989.     

Reaction of periclase crucibles with fused nickel alloy

Conclusions The authors have established the character of the reaction of periclase crucibles with fused nickel alloy. Tests on the crucibles under factory conditions have shown that nickel alloy remelted in them suffers no deterioration of its initial chemical and strength properties.Translated from Ogneupory, No. 6, pp. 25–27, June, 1980.     

Influence of additions on the conductivity of fused periclase

Conclusions In the 600 to 1200°C range fused periclase possesses a mixed ionic and electron conductivity (n- and p-types). With an increase in temperature the share of electron conductivity increases.Additions of flaky silicates containing Si⁴⁺ and Al³⁺ ions with a higher charge than Mg²⁺ promote a reduction in the total (ionic+electron) conductivity while with a partial pressure of oxygen close to 10⁵ Pa the share of electron conductivity decreases significantly. An especially significant reduction in conductivity is observed with the addition of hydroaluminum silicate to the periclase. A decrease in conductivity causes an increase in the electrical insulation properties of periclase.Translated from Ogneupory, No. 1, pp. 2–6, January, 1985.     

Properties of powders of fused spinels and periclase pulverized by different techniques

The properties of electrofused spinel and periclase powders prepared by different milling techniques are reported. Vibratory milled specimens display a higher structure imperfection of the surface, and the amorphous surface layer differs compositionally from the percursor material. In the pulverized products, contaminating elements (Na, Si, and, to a lesser extent, Fe) tend to migrate towards the surface of particles. Vibro-milled powders show a better sinterability in comparison to jet-milled powders. Pulverization produces little effect on the properties of precursor fused periclase.__________Translated from Novye Ogneupory, No. 12, pp. 36 – 42, December, 2004.     

Production of refractories from Chinese periclase

Periclase refractories from Chinese periclase are produced by the Chasovo-Yarsky Refractory Plant. The refractories have been tested with positive results at a number of metallurgical works, and specifications have been established for articles.Translated from Ogneupory, No. 1, pp. 21 – 26, January, 1995.     

Influence of the quality of fused periclase on the properties of plates and their service in sliding gates of steel-teeming ladles

Conclusions The authors have established that the structure and properties of periclase inserts and their durability during service in the sliding gates of steel-teeming ladles depend on the chemical and mineral compositions, the structure of the fused periclase, and the procedure used to obtain it.Translated from Ogneupory, No. 3, pp. 28–36, March, 1981.     

Service of fused periclase refractories in linings of converter steel discharge holes

Conclusions Periclase and periclase-spinel blocks for lining the discharge apertures of steel melting converters made on the basis of fused periclase, in conditions at the Chelyabinsk Metallurgical Plant, have a resistance of 164–214 heats.The maximum wear resistance is possessed by periclase-spinel blocks made on the basis of fused periclase which is confirmed by the minimum wear during the heat (despite the relatively high initial porosity of the products), the number of thermal cracks, the extent of the working zone, and also the minimum quantity of fusible new formations in this zone.Important significance, in order to guarantee sufficient service, is attached to the rational selection of the diameter of the channel in the blocks. In conditions at the Chelyabinsk Plant it is desirable to try blocks with a channel diameter of 140 mm.Further increases in the resistance of periclase and periclase-spinel blocks, made on the basis of fused periclase, to the action of liquid and gaseous reagents of the melt should be achieved by improving the chemical and phase compositions and structure (for example, reducing the quantity and size of the pores).Translated from Ogneupory, No. 2, pp. 30–37, February, 1973.     

Structure and properties of fused periclase and periclase-chromite blocks produced from beneficiated starting materials

Conclusions Fused periclase and periclase-chromite blocks containing a high proportion of highmelting oxides of magnesium and chrome were produced from beneficiated starting materials.The structure and properties of the periclase and periclase-chromite were analyzed zonewise in the blocks. The thickness of the block zones with a high content of magnesium oxide and the yield of high-quality periclase and periclase-chromite depend on the degree of purity of the chemical composition of the starting materials.The content of magnesium oxide is highest and the proportion of contaminating oxides low in fused periclase produced from chemically beneficiated Satkin magnesite, and in the monocrystalline subzones of the blocks. An increase in the proportion of chromite in the mix results in a higher porosity and in a higher content of spinel and ferrochrome in the fused material. The properties are optimal in the case of a periclase-chromite material from a mix containing 15–20% chromite.Translated from Ogneupory, No. 3, pp. 37–44, March, 1978.