Sustainable Mining and Metallurgy

Steel slag contains a large number of valuable elements, among which phosphorus is considered to be one of the most valuable elements. It is very important to recover phosphorus in steel slag efficiently. In this paper, the steel slag was modified by biological ash, and hydrochloric acid was used as leaching agent to study the leaching law of modified steel slag. The results show that the activities of Ca₃P₂O₈ and K₄CaP₂O₈ in the molten steel slag increase, and the activities of Ca₃SiO₅ and Ca₂SiO₄ decrease after biomass ash modification, which promote the formation of phosphorus-containing solid solution. The crystal form of the phosphorus-containing solid solution phase in the modified steel slag changes, which increases the dissolution rate of the solid solution. The modification treatment has little effect on the Mg-Fe phase; when the addition amount of biomass ash is 20%, the phosphorus leaching rate of steel slag can be increased from 39.91% to 61.12% in 0.07mol/L hydrochloric acid solution, and the iron leaching rate is only 23.86%.