Dissolution kinetics of P-bearing steelmaking slag in the citric acid solution

To achieve the high value-added utilisation of steelmaking slag, the separation of P from steelmaking slag is crucially important. Because P is primarily concentrated in the C2S–C3P solid solution, acid leaching was adopted to dissolve and separate the solid solution from the P-bearing steelmaking slag. The effects of leaching parameters on the dissolution behavior of P in the citric acid solution were investigated. The results indicated that decreasing particle size and pH significantly increased not only the leaching rate of P but also the dissolution ratio of P. Increasing temperature enhanced the leaching rate of P whereas had little influence on the dissolution ratio of P. At pH 5, the dissolution ratio of P reached 85.1% and only 6.7% of Fe was dissolved, achieving selective leaching of P. The dissolution kinetics of P followed the shrinking core model, which was controlled by the diffusion through the residue layer.