Steel Scrap and Scrap Sorting and Preparation Processes Jan23

Steel Scrap and Scrap Sorting and Preparation Processes...

Steel Scrap and Scrap Sorting and Preparation Processes Recycling of steel scrap is receiving increased impetus these days due to the focus of an emerging environmental initiative since the increased consumption of scrap reduces the needs for additional resource extraction and hence reduces the environmental impact. Recycling of steel scrap is also a part of wise management of iron resources. Recovery of 1 metric ton of steel from scrap conserves iron ore, coal, and limestone.  As per the world steel association, the integrated steelmaking route, based on the blast furnace (BF) and basic oxygen furnace (BOF), uses 1,400 kg of iron ore, 800 kg of coal, 300 kg of limestone, and 120 kg of recycled steel to produce 1,000 kg of crude steel and the electric arc furnace (EAF) route on average uses 880 kg of recycled steel combined with varying amounts of other sources (DRI, hot metal, and granulated iron), 16 kg of coal and 64 kg of limestone, to produce 1,000 kg of crude steel.  On an average, recovery of 1 ton of steel from scrap conserves an estimated 1,030 kg of iron ore, 580 kg of coal, and 50 kg of limestone. Steel scrap recycling also saves the energy consumption.  In the production of steel, 99.9 % of scrap melted is consumed in the production of new steel while producing negligible environmentally undesirable waste. Steel scrap is classified in three main categories namely (i) home scrap, (ii) new scrap, and (iii) old scrap depending on when it becomes scrap in its life cycle. Home scrap is the internally generated scrap during the manufacturing of the new steel products in the steel plants. It is also known as runaround scrap and is the material in the form of trimmings or rejects generated...

Iron Ore Agglomeration Processes and their Historical Development Dec28

Iron Ore Agglomeration Processes and their Historical Development...

Iron Ore Agglomeration Processes and their Historical Development There are four types of agglomerating processes which have been developed (Fig 1). They are (i) briquetting, (ii) nodulizing, (iii) sintering, and (iv) pelletizing. Fig 1 Agglomeration processes Briquetting is the simplest and earliest applied process. Fine grained iron ores are pressed in to pillow shaped briquettes with the addition of some water or some other binder under high mechanical compressive pressure. In the nodulizing process, fines or concentrate along with carbonaceous material are passed through inclined rotary kiln heated by gas or oil. The temperature inside the kiln is sufficient to soften but not high enough to fuse the ore. The nodules vary considerably in composition and are too dense, slaggy, lack required porosity and hence this process could not find great favour. Briquetting and nodulizing are cold binding processes and mostly used for the recycling of recovered iron ore wastes in the steel plant. Sintering and pelletizing are the processes of major importance for the iron production. During 2014, as per World Steel Association, the production of blast furnace iron and direct reduced iron were 1183 million tons and 73 million tons respectively. Most of this production has come from iron ore in the form of sinter and pellet. While the preferred feedstock for blast furnace iron is sinter and/or pellets, that of direct reduced iron is pellets only. Though accurate production data for sinter and pellets are not compiled, but world production of sinter and pellets together can be safely estimated to be well over 1300 million tons per year to support the iron production of 1256 million tons. Historically, the feedstock for the world?s blast furnaces was naturally occurring lump ores. During the mining of iron ores, large amounts were getting generated....