Production of fused periclase from natural raw materials

Increasing the number of uses of the refractories in the slide gates of large steel-teeming ladles

“…the formation of a stable angle of a natural bank of statistically invariant amount (Sav ~ 35 ~ ) and the formation of a certain contour of adjoining banks in the spatial area of the steel melting bath, which may be represented by a mathematical model --a parabola of rotation or the cavity of a two-sheeted hyperboloid [2].…”

“…* Kul'dur brucite, which is characterized by nonuniformity of its mineral composition and in external appearance and impurity content may be classified into eight varieties, was used as the original raw material [2]. The purest in chemical composition are dense uniform dull lumps of whitish-gray color and nodulized semitransparent light gray pebbles, which were selected for melting from a total quantity of brucite of 70 tons.…”

Mineral composition and microstructure of brucite from the Kul'dursk deposits

“…It is known that to obtain technical periclase by block fusion of brucite raw material, as a result of complex physicochemical processes of separation of the substance into liquid and gaseous phases, there occurs partial enrichment of the central zones of the block by magnesium oxide [4][5][6][7].…”

Intensification of the periclase electromelting process

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At the Magnesite Combine a method has been developed and introduced forelectromelting of brucite into a block [1][2][3][4] and of fired magnesite powder [5,6] and of periclase-spinellides [7][8][9] with obtaining of fused materials for new effective refractories [I, 6, 9, 10-15] in OKB-955N furnaces with a 1200 kVA ETMN 1600/10 transformer.During introduction of the method work was done in the direction both of improving the quality of the fused periclase and increasing furnace productivity.The quality of the periclase was improved by a periodic change in power delivered to the furnace during melting [2], a rational ratio of the powers on the higher and lower voltage steps of the transformer [16], an increase in purity of the original material [17,18], increasing the melting time [18], providing the conditions Pd > Psh reached at Zf < 5"10 .3 [19], changing the form of the bath shell, and increasing the intensity of heat dissipation from its surface [3,4].The productivity of the furnace was increased by supplying an oxygen enriched blast to the furnace [20], melting in a furnace with a current-and heat-conducting hearth [21,22], increasing the diameter of decomposition of the electrodes [7,18], increasing the current by 10-20% above the nominal, and the introduction of rational electrical conditions of melting

[4, 5].As the result of work done on an OKB-955N furnace with a 1200-kVA transformer with a diameter of decomposition of the electrodes of 1050 mm a maximum productivity in melting of magnesite, brucite, and fired magnesite powder of 258 [20], 260 [4], and 236 kg/h [6], respectively, was obtained.

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