Separation and recovery of calcium and iron from low calcium steel slag
ZHAO Shuhai1,2,3, JIN Yongli1,2,3,4, GUO Jiacheng1, ZHANG Kaixuan1,2,4, JIANG Jintao1,2,4
1. School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Baotou 014010, Nei Mongol, China; 2. Key Laboratory of Integrated Exploitation of Bayan-Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010, Nei Mongol, China; 3. Inner Mongolia Autonomous Region Carbon Neutrality Collaborative Innovation Center, Inner Mongolia University of Science and Technology, Baotou 014010, Nei Mongol, China; 4. Collaborative Innovation Center of Integrated Exploitation of Bayan-Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010, Nei Mongol, China
Abstract：Aiming at the urgent needs for comprehensive utilization of steel slag and emission reduction of CO2 faced by the iron and steel industry of China, calcium ions leaching was studied by choosing low calcium steel slag as raw material and acetic acid as extraction agent. After calcium and iron separation, calcium leaching solution was used to carbonate fixed CO2 to produce light calcium carbonate, and magnetic separation of iron from the leaching slag. By means of ICP, XRD, XRF, TG-DSC and other means, the leaching effect of calcium and iron in steel slag, the magnetic separation effect of leaching slag and the purity of precipitated CaCO3 were characterized. The results show that under the conditions of particle size [58,74] μm, leaching time 1 h, solid-liquid ratio 1∶10, acid concentration 2 mol/L and leaching temperature 40 ℃, the separation effect of calcium and iron is the best. After the leaching solution is modified, simulated flue gas is introduced, and 103.72 kg CO2 can be fixed per ton of converter slag, 240.1 kg CaCO3 can be recovered, and the purity of CaCO3 can reach 98.18%. Under the magnetic field intensity of 0.14 T, the magnetic separation effect of leaching slag is the best. The recovery amount of rich iron minerals can reach 201 kg per ton of steel slag, and the iron grade can also reach 57.3%. Calcium carbonate, a product of carbon fixation, can be used as filler in rubber and plastic industries, and iron rich minerals return to the steel production process, which can provid a reference for the effective utilization of steel slag.
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2023, Vol. 33 
