Recovery of Chromium from AOD‐Converter Slags

Abstract

Slags from the production of high‐alloyed steel contain both chemically bound chromium (mainly as Cr2O3) in the mineral fraction and elemental chromium in the metallic remainders. Thermochemical post treatment of the slag in an electric arc furnace under reducing conditions enables the nearly complete recovery of the total amount of chromium in form of a metallic alloy. The best results were achieved by resistance melting (submerged electrodes) with addition of a reducing agent into the melt. The efficiencies of the reducing agents carbon, aluminium, silicon (as ferrosilicon) and silicon carbide were investigated and compared. As aluminium is the strongest reducing agent, it is less selective and reduces much more SiO2 than Cr2O3. While SiC shows only low reactivity because of its high thermal resistance, carbon and silicon had the highest reducing potentials: More than 97% of the chemically bound chromium can be recovered by application of these reducing agents. Due to the high temperature required for the reduction of the chromium compounds, the reduction of SiO2 as an undesired side reaction cannot be avoided. However, compared with mechanical procedures that are limited to the recovery of the metallic remainders, the total chromium recovery can be significantly increased by the described reductive melting procedure.

Accelerated mineral carbonation of stainless steel slags for CO2 storage and waste valorization: Effect of process parameters on geochemical properties

“…The recovery of Cr, a valuable metal, from stainless steel slags could also circumvent this issue, and is being investigated (Adamczyk et al, 2010).…”

Effects of Fe2O3 on Reduction Process of Cr-Containing Solid Waste Self-Reduction Briquette and Relevant Mechanism

“…Fully recycling chromium in these solid wastes will not only improve enterprises' economic efficiency, but also reduce the risk of heavy metal pollution caused by Cr in solid wastes after being leached in the natural acidic or alkaline environment [6]. In all of Cr-containing solid wastes treatment technologies, high-temperature reduction technology using carbonaceous reductants has been paid extensive attention due to its unique characteristics compatible with metallurgical enterprises [5,[7][8][9][10]. Due to its excellent reactivity, self-reduction briquette bearing C was mostly adopted [11][12][13][14].…”

A Mathematical Model for the Reduction Stage of the AOD Process. Part II: Model Validation and Results

“…In spite of a suitable temperature window, 30) in the simulated heats the reduction of slag droplets by carbon was found to be inconsequential vis-à-vis the total reduction rate of Cr2O3. In the literature, it has been was suggested that reduction of Cr2O3 by C continues at a slow rate throughout the reduction period.…”