Thermal decrepitation of Pilbara (PB) lump ore: Characteristic, mechanism, and inhibitory strategy

Nowadays, more natural lump ores are directly used in blast furnace (BF) smelting to cut down costs and pollution issues. However, the decrepitation of lump ores at high-temperature deteriorates the permeability of BF operation. In this work, thermal decrepitation behavior of the PB lump ore was studied based on the international standard (ISO 8371). Effects of temperature, duration, lump size, the type and content of moisture on thermal decrepitation of PB lumps were investigated. The significant roles of heating temperature and crystalline water in lump ore were identified, while the critical decrepitation condition was determined. Decrepitation mechanism can be clarified as vapor pressure accumulation caused by crystalline water decomposition via TG-DSC, mercury porosimeter and SEM-EDS analysis. Inhibition method was developed from aspects of crystalline water decomposition and vapor diffusion to reduce the pressure accumulation. The decrepitation index (DI-6.3) of PB lump ore can be cut down from 17.5% to 0.4% effectively.