Comparison of Iron and Chromium Reduction from Chrome Ore Concentrates by Solid Carbon and Carbon Monoxide

Abstract

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.

Main Directions of the Electrochemical Chrome Plating Process Intensification

“…There is an extensive class of organic substances that can be used as additives to intensify the chrome plating process [7]. In [8][9][10], chromium plating electrolytes based on chromic acid solutions with additions of gallic acid and methylene blue of the following composition (g/l) were proposed and investigated: 1) chromic anhydride is 200…50, sulphuric acid is 2…3, gallic acid is 2…3; 2) chromic anhydride is 200…250, sulphuric acid is 2…3, methylene blue is 1…6. The deposition temperature for the first variant is 45…55 °C, for the second is 60…70 °C.…”

Pilot Tests of Pre-Reduction in Chromium Raw Materials from Donskoy Ore Mining and Processing Plant and Melting of High-Carbon Ferrochromium

“…Materials used in [14] have been supplemented by our calculated data on the total power consumption, including the power consumption with a coefficient of efficiency of 40%. The schemes of the metallurgical coke used as reducing agent and fuel for the annealing and sintering processes have been supplemented by the power consumption for coking in accordance with the data described in [15][16][17][18][19][20][21]. According to the information presented in Table 1, it is evident that the utilization of a pre-reduction process for chromium raw materials in ore-smelting and DC furnaces results in the most efficient power consumption.…”