GB686831A - Improvements in process for manufacturing hypereutectic cast-iron and products thereof - Google Patents

Abstract

In a shaft furnace process for the production of iron, the temperature in the melting zone is controlled by means affecting the formation temperature of the slag. The resultant slags are self-pulverizing and contain alumina in the form of soluble calcium aluminates from which the alumina may be obtained. The compositions of the slags lie between silica 8-22 per cent, alumina 20-44 per cent, lime 48-58 per cent part of the lime being replaceable by a molecularly equivalent amount of magnesia. Specification 632,945 is referred to.ALSO:In a process for manufacturing hypereutectic iron containing up to 5.2 per cent C, 0.1-1.0 per cent Si, less than 0.02 per cent S and 0.3 to 5.0 per cent Mn the temperature in the melting zone is adjusted by means affecting the formation temperature of the slag so that different compositions of iron may be obtained for a predetermined composition of slag. A high slag-formation temperature may be obtained by using pure slag-forming constituents of large size and a low temperature by using small particles of slag-forming substances intimately mixed together and preferably briquetted. The preferred slag compositions lie within the limits silica 8-22 per cent, alumina 20-44 per cent, lime 48-58 per cent, a portion of the lime being replaceable by a molecularly equivalent amount of magnesia. The slag should not contain more than 1.0 per cent of iron oxide. The iron may also contain up to 2 per cent V, up to 0.8 per cent Mo, up to 3.0 per cent Cr, up to 4 per cent Ni and up to 2 per cent Ti. Specification 632,945 is referred to.