Pre-Reduced Iron Produced From Low Grade Ore Using Biomass

摘要

The treatment of ore containing iron oxide hydrate has been proposed in order to utilize low grade iron ore in the iron steel industry due to shortage of high grade ore deposit soon in the near future. At present, the use of low grade iron ore such as limonite is relatively high cost and high energy consumption if compared to the commercial high grade ore. In fact, there are many domestic energy resources such as waste biomass from industry that has not been utilized effectively. This work focused on the pre-treatment of limonitic ore by using waste rice husk through pre-heating and gasification processes. The ore was pre-heated at 400°C for 1 h under atmosphere and about 11 mass% of weight loss was obtained due to releasing of moisture and crystalline water and generated crack that produce high porosity of material. The process upgrades the iron content in the ore by changing the complex iron oxide hydrate into simple hematite compound. Treatment of pre-heated ore with rice husk was performed using a vertical electric furnace with silica tube crucible inside. Amount of rice husk was put at the bottom part and the ore at the top part of silica tube then was heated up at desired temperature for 15 minutes under argon gas flow before it was cooled down to room temperature. The iron oxide was simultaneously reduced by reducing gases produced from gasification process, consequently, reduced the sample weight by releasing oxygen. The treated sample had low porosity and the particles were sticky caused by trapping of tar into the pore materials. The results revealed that the waste, rice husk is a promising energy source to produce pre-reduced iron from limonitic ore and will reduce carbon dioxide emission by replacing a part of fossil fuel or coal consumption in the iron making process.