3.Study on calcium leaching from converter slag by ammonium salt and preparation of calcium carbonate

Abstract:

Aiming at the problem of low leaching rate of calcium in converter slag. In the experiment, low-calcium converter slag was used as raw material, and different leaching media and external field action methods were used to improve the dissociation degree of calcium in converter slag and promote its combination with CO2. The results showed that the leaching rate of Ca was 77.5 % when the microwave power was 720 W, the particle size was(58,75]μm, the solid/liquid ratio was 1∶30 g/mL, the leaching time was 120 min, the stirring speed was 300 rpm, the ammonium salt concentration was 3 mol/L, and the temperature was 60 ℃. At the same time, the content of Fe2O3in the leaching residue increased by 19.22 %. High-purity CO2was pumped into the leaching solution at a flow rate of 0.2 L/min. The results showed that 150.1 kg of CO2could be fixed per ton of converter slag, generating 341.2 kg of calcite CaCO3with a purity of 98.13 % and a particle size of 10～15 μm.

Keywords: converter slag;microwave field;leaching rate;carbonation reaction