Abstract A sintered agglomerate consisting essentially of carbides and oxides of chromium and iron and consisting of a core covered with a dense and tough skin of metal oxides, both of which contain the same metallic elements at substantially the same proportions but contain no free carbon. This agglomerate possesses great mechanical strength and does not powder and, in addition, has properties which make it suitable for use as a starting material for producing chromium-containing ferroalloys in an electric furnace. This agglomerate is produced by pelletizing a mixture consisting of powdered chromite and a small quantity of powdered carbonaceous material, drying and preheating the resulting pellets and thereafter roasting the pellets using a combustive flame in an oxidizing high temperature zone.
The agglomerate of claim 1 wherein said agglomerate is nearly spherical and has a diameter of 10 to 30 mm.
Claim 2
Dependent Claim
15 words
The agglomerate of claim 1 wherein said skin is about 0.2 to 2 mm thick.
Claim 3
Dependent Claim
111 words
A process for producing sintered agglomerates consisting essentially of carbides and oxides of chromium and iron and incidental impurities but containing no free carbon, comprising mixing a chromite ore and powdered carbonaceous material to produce a chromium/iron weight ratio ranging from about 1.5 to about 4.0 and a carbon coefficient ranging from about 0.5 to 1.0; pelletizing the mixture of chromite ore and carbonaceous material, drying and preheating the pellets, charging the pellets into a high temperature zone of from 1,200* to about 1,500*C. formed by the combustion of a fuel in the presence of excess oxygen so that said ore is substantially reduced and rolling said pellets while being reduced.
Claim 4
Dependent Claim
26 words
The process of claim 4 wherein said ore and said carbonaceous material are mixed with about 2 to 6 percent of a binder before being pelletized.
Claim 5
Dependent Claim
15 words
The process of claim 4 wherein said temperature is from about 1,300* to about 1,500*C.