GB781108A - Improvements in the reduction of metallic ores - Google Patents

Abstract

781,108. Reduction of metallic ores; slags. SOC. FORNI LUBATTI. March 15. 1955 [March 20, 1954], No. 7571/55. Classes 72, 82(1) and 82(2) A method for the production of metals from granular ores in a slag resistance furnace comprises preparing a molten slag layer in a furnace feeding comminuted ore and reducing agent on to the molten slag layer to a depth of more than four inches, maintaining the current transmitting portions of electrodes below the surface of the charge layer and discontinuously removing the metal and slag. The size of the ore is under one millimetre and that of the reducing agent under five millimetres. As shown, a furnace 11 has two electrodes 13, 14 having current transmitting portions 17, a slag layer 18, a charge layer 19 and a reduced 'metal layer 22. That portion of the electrodes above the portions 17 should be electrically and thermally insulated by a coating 21 and the portion 17 should lie within the lower third of the charge layer and the upper third of the slag layer. The thickness of the three layers is of importance in the operation of the process and should lie within the following ranges: charge layer 4-20 inches, slag layer 16-28 inches, metal layer 12-32 inches, and further, the charge layer should not exceed one-sixth of the largest horizontal dimension of the furnace. The reducing agent may be coal and up to 15 per cent may be added in the form of pieces 15-45 m.ms. in size. The slag may be formed by melting 50 per cent calcium oxide and 50 per cent kaolin to produce a slag consisting of 46.7 per cent CaO, 4 per cent MgO, 36 per cent SiO 2 , 11.5 per cent Al 2 O 3 , the balance being impurities. Specifications 695,158, 717.576 and 745,001 are referred to.