Selective solid-phase reduction of iron in phosphorous oolite ores

Abstract

Selective solid-phase reduction of iron and phosphorus in oolite ores of the Lisakovsky and Ayat deposits was experimentally studied. Using X-ray phase analysis, the phase composition of the initial ores and samples after reduction roasting was determined. Goethite, magnetite and quartz were found in the ores of both deposits. Phosphorus in the ore of the Ayat deposit is in the form of aluminum phosphate and iron hydrophosphate, and in the samples of the Lisakovsky ore – as a component of calcium hydrophosphate. Experiments on reduction roasting were carried out in a resistance furnace at 1000 °C with holding time of 5 h. After roasting in CO atmosphere, α-Fe appears in the samples, while phosphorus remains as a component of iron, calcium and aluminum phosphates. After roasting in a mixture with graphite, phosphorus is reduced by solid carbon from iron and calcium phosphates and passes into metal, but remains as a component of aluminum phosphate. Studies using microroentgenospectral analysis show that phosphorus content in the metal phase after reduction with solid carbon is 2.0 – 3.5 at. %. When CO is reduced in the atmosphere, phosphorus in the metallic phase is practically not detected. At the same time, the amount of residual iron in the oxide phase after carbon monoxide reduction significantly exceeds the amount of iron after reduction in a mixture with carbon. The experimental results confirm the possibility of selec­tive reduction of iron by carbon oxide CO without phosphorus reduction.