CPR pellets - a blast furnace grade

Abstract

It has been proven theoretically and experimentally that the use of 10-30 per cent DRI in blast furnace along with iron ore or sinter results in lower coke rate and higher productivity. However, to-date this remains unpractised on a regular basis mainly because of economic reasons. The DRI produced by several methods are expensive and difficult to store/handle in large quantities because of its reactive nature and thus DRI in blast furnace remains unacceptable. CPR (Composite Pre-Reduced) pellets developed at BHU-Varanasi (India) is a kind of DRI which indicates less storage problems and estimated to be cheaper than coke price in India. CPR pellets contain iron in highly metallised state in the core encased in partially reduced shell of iron oxide as protective layer for safe and easy storage. The lower cost of CPR pellets is mainly because of the use of cheap raw materials and energy source for firing without needing expensive reducing atmosphere for causing metallisation in the pellet. The pellet firing system is simple requiring less capital. The paper gives details of the CPR pellet preparation technique and then it evaluates its chemical and physical properties for blast furnace use. It also gives the estimated cost of production under Indian condition and mentions the various merits associated with the use of CPR pellet in the blast furnace. The status of the project is described before concluding the paper.