Process research and development for ironmaking at low temperature by the reaction of steam with a mixture of iron ore and low rank coal

Research Project

Project/Area Number	62550715
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	反応工学
Research Institution	Okayama University
Principal Investigator	KASAOKA Shigeaki Professor, Faculty of Engineering, 工学部, 教授 (10032921)
Co-Investigator(Kenkyū-buntansha)	SAKATA Yusaku Associate Professor, Faculty of Engineering, 工学部, 助教授 (70032951)
Project Period (FY)	1987 – 1988
Project Status	Completed (Fiscal Year 1988)
Budget Amount *help	¥1,800,000 (Direct Cost: ¥1,800,000) Fiscal Year 1988: ¥300,000 (Direct Cost: ¥300,000) Fiscal Year 1987: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywords	Brown coal / Iron ore / Coal gasification / Synthetic gas / Direct reduction / Metallic iron / Sponge iron / ロータリーキルン / 直接還元法 / ロータリーキルン反応器 / ヘマタイト / マグネタイト / リクナイト / キルン型反応器
Research Abstract	A blast furnace has been an established process for ironmaking. But it must be operated at high temperature above 1300゜C by applying which coke works as heating fuel and reducing agent. Since material coal for the coke must be specified with their chemical and physical characters, supply of coking coal will have limitations in the future from points of resources and price. Therefore new technologies for direct reduction of iron ore based on alternative fuel resources are eagerly expected. In this study we considered the low rank coal such as brown coal and lignite. They have higher reactivity in steam gasification to produce synthetic gas (a mixture of hydrogen and carbon monoxide), and have higher moisture holding capacity. The objective of this study is to show experimentally the feasibility of the bifunctional process for a coal gasification with steam and a direct reduction of iron ore with hydrogen and carbon monoxide formed from coal gasification. An Australian brown coal "Yallourn" and a Canadian lignite "Highvale" were applied for grain mixtures with Newman hematite (Fe_2O_3) ore and Romeral magnetite (Fe_3O_4) ore. The average diameters of coal and ore were in the range of 0.125-0.5mm, and both solids were mixed mechanically. By semi-batch and continuous operations, experiments on simultaneous gasification and reduction of the coal/ore mixtures were carried out with a thermo-balance and a micro scale rotary kiln reactor equipped with a gear feeder designed for this study. It was confirmed that iron sponge and synthetic gas were successfully obtained below 900゜C from the grain mixture of coal and hematite ore, by streaming a mixture of low level (<3%) steam and nitrogen at a low flow rate. The minimum mixing ratio of coal to hematite ere about in the level of 0.5-1 in mass. Principally the operational variables must be chosen for the solid mixture to be processed in the reactor for a long period.