Intensification of the periclase electromelting process

Abstract

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.