An alkaline roast-leach process for treatment of titaniferous magnetite for recovery of chromium, vanadium & aluminum

CIM Bulletin, Vol. 73, No. 821, 1980

B.H. LUCAS and G.M. RITCEY, Hydrometallurgy Section, Extractive Ore Processing Laboratory, Mineral Sciences Laboratories, CANMET, Energy, Mines and Resources Canada

On the north shore of the St. Lawrence River, in Quebec, are located orebodies of low-grade titaniferous magnetite.   The Quebec Mining Exploration Company (SOQUEM), who have an interest in the deposits, believed that beneflciation of the could generate sufficient revenue to defray the mining costs and the costs of transporting the ore to a steel production facility. A joint research project of SOQUEM and CANMET investigated alkaline roasting of a magnetic concentrate, followed by leaching of the calcine and separation and recovery of Cr and V by solvent extraction. Aluminum was recovered by precipitation.The present paper describes the roast-leach bench-scale and pilot-plant work leading to the development of the optimum conditions for the integrated process.A plant flowsheet was developed for the treatment of 5 x 106 tons of magnetic concentrate per annum. Estimates of capital and operating costs were made.Based on a recovery of approximately 90% V, 85% Cr and 75% Al, the total hydrometallurgical plant fixed capital costs, including mining, concentration and shipping, are estimated at $1.021 x 109; the operating costs are estimated at $131.92/ton concentrate. Annual revenue from the Na2CrO4.H2O, V2O5 and Al2O3 produced is calculated to be $421 x 106.
Keywords: Roasting, Leaching, Magnetite, Titaniferous magnetite, Chromium, Vanandium, Aluminum, Hydrometallurgy, Alkaline solutions.