Selective leaching behaviour of calcium and magnesium from steel slag
LIANG Zhu1, LI Jia1, LI Peng2, YAN Bing-ji2, GUO Hong-wei2
1.Key Laboratory of Metallurgical Equipment and Control Technology, WUST, Ministry of Education, Wuhan 430081, Hubei, China; 2. Shagang School of Iron and Steel, Soochow University, Suzhou 215021, Jiangsu, China
Abstract：Steel slag with high amount of alkaline oxides is potentially raw material for CO2 mineralization. The effects of slag particle size, leaching temperature, leaching time, solid-liquid ratio and acetic acid concentration on the dissolution behavior of calcium, magnesium, iron, and silicon in steel slag were investigated, and acetic acid was used as extractant. The results showed that the reduction of the particle size of steel slag and the increase of acetic acid concentration could promote the leaching of calcium and magnesium ions effectively. Meanwhile, it was found that increasing the leaching time would lead to a decrease in the leaching rate of iron and silicon ions. Under the conditions of acetic acid concentration of 1 mol/L, leaching temperature of 80 ℃, leaching time of 90 min, and solid-liquid ratio of 1∶20, the selective and efficient leaching of calcium and magnesium ions from steel slag can be achieved, and the maximum leaching rate reached 92% and 52%, respectively, while for iron and silicon ions, it was 29.5% and 15.9%, respectively. The phase analysis of the leaching residue indicated that the main phase was RO phase. It was suggested that the acetic acid leaching not only efficiently extracted calcium and magnesium, and its leaching solution could be used as raw material for carbonation. The filter obtained after leaching was rich in iron-containing phase and can be further recovered as a high-grade ironmaking raw material.
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2020, Vol. 30 
