(p590) IMPROVED RAW MATERIAL EFFICIENCY IN HOT METAL PRODUCTION

摘要

Raahe Steel Works of SSAB Europe has closed sinter plant in 2011 and started to use of iron ore pellets with coldbonded briquettes in blast furnaces. The new briquette plant was started in March 2012 and the processing of therecycled materials was started. Those materials had been earlier processed via sinter plant. Until the turn over fromsinter to pellets with starting of briquetting plant had carried out, a high effort to develop material efficiency in hotmetal production was allocated. The project was named as “Material efficient blast furnace”. The aim was tomaximize usage of briquettes and recycling of other secondary raw materials usage directly to blast furnace.Fe-fines, coal-dusts, mill scale and metallic scrap has been managed to recycle into blast furnace. Cold bondedbriquettes have been manufactured and used as much as all recyclable materials are forming in the steel mill. Thequalities of briquettes were improved to acceptable level after some variations during the first production months.The target usage of briquettes has been exceeded and the level 140 kg/tHM has been reached in 2013 withoutdisturbing blast furnace process. Total coke rate reduced in the blast furnace due to carbon in recycling materials.The improved material efficiency leaded to two significant results: secondary carbon materials utilization asreducing agent increased from 3% up to 6% and the amount of virgin pellets in iron charge were reduced from 95%down to level 88% by using secondary raw material including briquettes during the 2 - 2.5 year period.