Upgrading of manganese from waste silicomanganese slag by a mechanical separation process

Abstract

Large amounts of silicomanganese slag are generated and discarded from the silicomanganese alloy smelting furnaces that treat ferromanganese slag to produce silicomanganese alloy, which contain 10-14 mass% Mn. It is thus important to find a possibility for recovering manganese from silicomanganese slag in terms of environmental and economic points of view. Upgrading of manganese from the silicomanganese slag for recycling the slag back to the silicomanganese furnaces must be necessary to decrease the slag volume which causes irregularities in their operation. In this study, a physical separation process for the upgrading of manganese from silicomanganese slag discarded has been suggested. The process first grinds silicomanganese slag between -500 μm and +75 μm, followed by the dry magnetic separation process to separate and concentrate manganese from the ground slag. Based on the results obtained, a manganese rich slag which contains over 20 mass% manganese was calculated to be separated and concentrated from silicomanganese slag under a magnetic field of about 6,000 Tesla using the proposed process. The manganese rich slag obtained should be used as a manganese resource for manufacturing silicomanganese alloy. © 2011 The Japan Institute of Metals.