Determining the Conditions for Selective Iron Recovery by Iron-Manganese Ore Reduction

The results are presented for the thermodynamic simulation of reductive roasting of ferromanganese ore with a high phosphorus content in the presence of solid carbon. The simulation has been performed using a TERRA software package. An effect of the process temperature in the range of 950–1300 K at a carbon content amounting to 8.50–8.85 g per 100 g of ore exerted on iron, manganese and phosphorus reduction has been studied. At such parameters of the system, iron can be reduced into the metallic state both by solid carbon and by carbon monoxide CO, whereas manganese can be reduced only to produce manganese oxide MnO. The level of phosphorus reduction depends on the amount of a reducing agent. With the carbon excess in respect to the carbon amount required for the reduction of iron, the entire amount of phosphorus is transferred into metal at a temperature of 1150 K. At a temperature below 1150 K and such amount of carbon, phosphorus cannot be reduced. The process of solid-phase iron reduction from manganese ore with retaining manganese in the oxide phase has been studied under laboratory conditions. Experimental results for the direct reduction of these elements with the use of carbon and those for indirect reduction thereof with the use of carbon monoxide CO are presented. The experiments have been performed using a laboratory Tamman furnace at a temperature of 1000–1300°C and at a holding time of 1 and 3 h. The study results on the phase composition of the reduction products, as well as on the chemical composition of the phases, are considered. It is confirmed that selective solid-phase iron reduction with the use of solid carbon into the metallic state is quite possible. Iron under the studied conditions can be reduced by carbon monoxide CO and is transferred into the magnetic fraction. After the magnetic separation of the products of ore reductive roasting with the use of solid carbon and carbon monoxide CO, the obtained nonmagnetic fraction contains manganese, silicon and calcium oxides. The results of this work could be used for the development of theoretical and technological foundations of the processing of ferromanganese ores that cannot be processed by means of existing technologies.