The possibility of reduction of chromium and iron from complex oxides by gaseous carbon monoxide and solid carbon was investigated. The chromium ore concentrates of Kempirsai and Aganozero deposits used in present study had different ratio of iron and chromium content. The Reduction in CO gas atmosphere did not result in reduction of chromium and iron from spinels; however, it resulted in reduction of fines from the drying apparatus, where the particles of coke presented along with the particles of the Kempersai chromite. At the same time, iron and nickel were reduced from the silicates of the gangue minerals. In the samples mixed with solid carbon a continuous layer of carbides formed on the surface of the spinel grains. The formation of a continuous shell retarded and practically stopped the reduction process. The further development of reduction was possible after destruction of the shell that occurred as a result of smelting of the carbides and silicides mixture that constitute the shell.