Re-using waste from steelmaking carries a number of advantages. The steelmaker has one more product to sell, customers such as the cement industry can reduce their emissions, both can improve thier cost-effectiveness. And of course the re-used waste does not end up in a landfill.
SBB 14 May China’s Anshan Iron & Steel (Angang) plans to invest heavily in slag processing this year, increasing capacity from under 1m tonnes/year currently to 5m t/y by the end of the year by installing four new slag milling units supplied by Germany’s ThyssenKrupp Polysius.
This should help reduce input costs and increase revenues for the steelmaker, Su Xingwen of the Slag Development Co. of Ansteel told delegates to the China International Metal Recycling Conference in Beijing.
Angang can currently produce up to 160,000 t/y of >95% Fe iron nuggets and 180,000 t/y of 60% Fe iron oxide concentrates from its slag processing facilities, helping to reduce input costs. This operation generated RMB 1.02bn of revenue last year. The refined iron nuggets are produced using one of Angang’s first patented technologies and can be used directly in the oxygen converter.
Once valuable minerals have been extracted, steel slag tailings can be ground to a powder and sold to cement and concrete producers. Angang produced 1.3m t of tailings when it produced 16m t of steel in 2009. By 2015, when it expects to produce 60m t of steel, it aims to produce 4m t of tailings.
In theory, capturing the 6 trillion KJ of heat contained in the 3m t of slag produced at Angang’s main steelworks annually could also reduce costs by around RMB 100m ($15.8m), Su estimated. Angang reported a net loss of RMB 2.1bn in 2011, as Platts Steel Business Briefing has reported.