Iron recovery and dephosphorization behaviors from high-phosphorus oolitic hematite by gas-based direct reduction and magnetic separation

Abstract

With the depletion of high-quality iron ore resources, high-phosphorus oolitic hematite (HPOH) has attracted great attention due to its large reserve and relatively high iron content. However, HPOH is very difficult to be used in ironmaking process due to its special structure. A two-step method of gas-based direct reduction and magnetic separation was thus proposed to recover iron and reduce phosphorus. The results showed that the powdery reduced iron produced contained 92.31% iron and 0.1% phosphorus, and the iron recovery was 92.65% under optimum reduction condition, which is suitable for following steelmaking. The apatite will be reduced under long reduction time and a large reducing gas flow rate, resulting in more phosphorus found in the metallic iron. Increasing the hydrogen–carbon ratio will inhibit the formation and growth of iron particles and prevent the breakage of oolitic structure. Careful adjustment of reduction temperature is recommended as it affects the oolitic structure and reduction.