Applied investigation on waste minimization in an integrated steel site

Abstract

Recycling is of major interest in steel making for environmental reasons as well as economical. All process units produce secondary materials which are recycled, sold or put in landfill. This work evaluates simulated cases for recycling of materials at an integrated steel site. Case studies and industrial tests of different recycling options have been performed. The main focus has been on residues produced in significant quantities and materials put in landfill due to their physical or chemical nature. Chosen case studies have been tested in industrial scale and comprise of recycling of dust, sludge and ladle slag to the blast furnace. The results from test periods have been used to compare modelling with process parameters. Industrial tests show that it will be beneficial to recycle steel plant (BOF) sludge via briquettes to the blast furnace but the main issue is the drying of the sludge. Furthermore ladle slag can be used as slag former in the BF with no negative effect on the process or product. The main advantage is that the resource efficiency increases since less virgin material is used and the depositing of secondary materials is decreased. Major cost savings can be found if internal recirculation can replace raw material such as iron ore, coke and lime stone.