Production of High Grade Manganese Products from Cuyuna R-N Tailing

摘要

In this project the R-N reduction was carried out on a fine-grained Cuyuna ore in a manner such that iron grain growth did occur. Under these conditions a high-grade iron product was obtained at high iron recovery, but much of the manganese in the ore was converted to manganese silicates and could not be recovered by leaching the tailing. An R-N reduction could be carried out on a Cuyuna ore in a manner such that the formation of manganese silicates would be prevented, thus assuring high manganese recovery in the leach circuit, but a low-grade iron product at low recovery would be obtained because there would be but little iron grain growth. The higher the silica content of Cuyuna ores, the greater is the tendency for them to form silicates of iron and manganese during R-N reduction, thus decreasing the recovery of iron in the magnetic separation step and the recovery of manganese in the leaching step. The manganese in Cuyuna R-N tailing is so closely associated with siliceous gangue that physical concentration techniques are ineffective.