Recovery of Hematite from The Coal Boiler’s Bottom Ash by Column Flotation for Sponge Iron Production

Abstract

The total amount of asphaltite resource in reserves and production in Şırnak City are over 120 million tons of available asphaltite reserve and about 600 thousand tons per year, respectively. The asphaltite is used in mainly coal boilers for direct heating, and also in industrial furnaces as coal fine. The combusted asphaltite discarded as the boiler bottom ash contains 15% hematite at fine size from furnace The most effective and cost-effective technologies are needed for iron ore products in today's modern technologies. Turkish pig iron industry needs sponge iron products and related technologies and high quality at lower cost with various types of local iron resources should be investigated. In this investigation, a comparison was done between the use of poor hematite ores containing 15% hematite and the regional coal boiler bottom ash discarded as municipal waste 120 thousand tons per annum. The column flotation tests used oleic acid and pine oil as collector and frother to float hematite in the bottom ash, respectively. The flotation performances versus the amount of collector and pH ranged to 5 kg/t and 11, respectively, were determined as the reduced hematite recoveries of 63% and 45%. The less amount may resulted better (70% to 85%) hematite recoveries. In the tests of sponge iron production reductive roasting at 1000C with coal fine for different times, namely, 40 min, and 80 min of the hematite pellets were converted to sponge iron and the properties of the sponge iron ere determined. The burned coal in reductive roasting showed that volatile gases amount and quality affected on reductive roasting of hematite pellets to sponge iron. The iron oxide groups showed that the hematite quality will enhance the quality of sponge iron. Further reductive roasting provides much higher metal conversion.