PHOSPHORUS SEPARATION METHOD FOR STEEL-MAKING SLAG AND PHOSPHORUS SEPARATION APPARATUS FOR STEEL-MAKING SLAG

摘要

PROBLEM TO BE SOLVED: To provide a phosphorus separation method for steel-making slag and a phosphorus separation apparatus for steel-making slag, by which phosphorus can be separated with high separation property from steel-making slag essentially comprising CaO and the like.;SOLUTION: The method includes a first step of oxidizing steel-making slag, a second step of pulverizing the steel-making slag, a third step of immersing the pulverized steel-making slag in a liquid having a prescribed pH, and a fourth step of separating a solid component from a liquid component in the liquid. In the first step, the steel-making slag is oxidized by converting iron oxide included in the steel-making slag into Fe₂O₃ and/or Fe₃O₄ to reduce the FeO concentration to 1 mass% or less. The steel-making slag prior the oxidation has a solid solution phase comprising tricalcium phosphate (3CaO P₂O₅ at a concentration C3P) and dicalcium silicate (2CaO SiO₂ at a concentration C2S) as components. In the solid solution phase, a ratio of C3P/(C2S+C3P) is 0.25 or more and 0.95 or less.;COPYRIGHT: (C)2013,JPO&INPIT