Process for manufacture of high-chromium iron alloy

A process for the manufacture of a high-chromium iron alloy containing a total of not less than 90% of iron and chromium and having a Cr/Fe weight of not less than 4.0 and a silico-chromium alloy, which process comprises the steps of mixing a chromium ore containing chromium oxide and iron oxide at a Cr/Fe weight ratio of not less than 1.6 with quick lime, heating the resultant mixture to melt it and produce a primary slag, adding to the primary slag at least one silicon-containing reducing agent selected from the group consisting of metallic silicon, silicon-chromium, ferro-silico-chromium and ferro-silicon in an amount such that the silicon content thereof equals 0.2 to 0.8 times the theoretical amount required for reduction of the iron oxide and chromium oxide present in said primary slag and such that the secondary slag subsequently obtained has a Cr/Fe weight ratio greater than 5, heating the primary slag incorporating therein the added reducing agent at temperatures not less than 1,600.degree. C. to undergo reaction, allowing the primary slag which has undergone said reaction to stand at rest for thereby producing a secondary slag in the upper region and a metal phase in the lower region, separating the metal phase to obtain a by-produced metal containing from 20 to 65% by weight of chromium, adding to the secondary slag phase at least one reducing agent selected from the group consisting of metallic silicon, silicon carbide and silico-chromium having no iron content while said slag phase is maintained at temperatures of from 1,750.degree. to 2,050.degree. C. for thereby inducing a reaction, allowing the secondary slag which has undergone said reaction to stand at rest for thereby producing a tertiary slag phase in the upper region and an iron alloy phase containing a total of not less than 90% of iron and chromium and having a Cr/Fe weight ratio of not less than 4.0 in the lower region, separating the lower phase to obtain a high-chromium iron alloy containing a total of not less 90% of iron and chromium and having a Cr/Fe weight ratio of not less than 4.0, adding to the tertiary slag phase metallic silicon in an amount in excess of the theoretical amount required for reducing the chromium oxide and the metallic chromium present in said tertiary slag an heating the slag and the added reducing agent at temperatures exceeding 1,550.degree. C. for thereby inducing a reaction, allowing the tertiary slag which has undergone said reaction to stand at rest for thereby producing waste slag in the upper region and a silico-chromium alloy phase in the lower region, and separating the silico-chromium alloy phase to obtain silico-chromium.