Prevention of chromium elution from stainless steel slag into seawater

Abstract

Utilization of steelmaking slag is indispensable for sustainable growth of steelmaking industry. Steelmaking slag contains nutrition such as phosphorus, silicon and iron and may be utilized as a fertilizer if elution of environmentally regulated elements is negligible. Chromium is contained in stainless steel slag as an oxide and stabilization of this chromium oxide in the slag is very important in the view of environmental protection. Elution behavior of elements from chromium containing phases into seawater was investigated to observe the stability of phases that may exist in steelmaking slag. It was found that the existence of 2CaO·SiO2 enhanced the dissolution of chromium into seawater. Elution behavior of chromium from especially synthesized stainless steel slag into seawater was investigated. Finally, fixation of chromium was conducted by control of mineralogical phase with SiO2 addition to stainless steel slag. Addition of SiO 2 to the slag was very effective for prevention of chromium elution into seawater. © 2011 ISIJ.