Removal of phosphorus and enrichment of manganese from a complex ferruginous manganese ore

Abstract

Attempts were made to enrich manganese content as well as Mn/Fe ratio from a complex manganese ore from Nishikhal deposit, Orissa, India, containing 32% Mn, 18% Fe, 16% SiO2, 21% acid insolubles and 0.45% P by reduction roasting followed by magnetic separation route. Interestingly the adopted route not only enriched the Mn content to around 40%, Mn/Fe ratio to around 10 but also brought down the P to around 0.3% in the non-magnetic product there by making this deposit as a potential feed for ferro-manganese production in the country. Although the enrichment of Mn and Mn/Fe ratio is expected by this route, 60% of the phosphorus reduction is primarily due to the presence of P in association with goethite while the rest of the P was observed to be associated with the manganese phases and as apatite within the silicate phases as confirmed by the optical microscope and electron microscopic studies. The paper also discusses the limitation of reducing the P content further in the beneficiated product.