As for the iron ore used in blast furnaces nowadays, every 100 tonne of run-of-mine (RoM) iron ore contains around 78 tonne of high-quality iron ore and the rest is iron ore slime, which has high gang content, i.e., silica, alumina and other impurities.
As per the current guidelines, iron ore bearing less than 55% iron is not considered iron-bearing material worth processing.
But very soon they (the government) will come out with regulation saying that anything above 45% (iron ore) should be used, said Tata Steel CTO T Venugopalan, speaking to FE. Venugopalan added that Tata Steel is trying to develop quite a few processes that promise use of such waste material.
Prominent among the projects undertaken by the steel major is the making of very strong cold-bonded briquettes out of waste iron ore slime, which will be used as coolant for its LD converters.