Effective removal of phosphorus from high phosphorus steel slag using carbonized rice husk

High phosphorus steel slag and carbonized rice husk are two common wastes characterized by high generation and low secondary use values. Through the reduction of high phosphorus steel slag by biomass, both wastes were fully utilized, thus reducing the negative impact on the environment. In this study, variables such as temperature, time, and amount of reactants were changed to determine the optimal conditions for the reaction of steel slag with carbonized rice husk at high temperatures. The actual amount of reducing agent consumed during the reduction was significantly greater than that predicted by theoretical calculations. Adding three carbon equivalent of carbonized rice husk and maintaining at 1500°C for 30 min could remove 79.25% of P₂O₅ in the slag. By modeling the material cycle in which high phosphorus steel slag was treated with biomass, the product could be used for crop growth. Meanwhile, the reduced iron and residual steel slag can be used to make steel again, thereby leading to a sharp reduction in fossil fuel usage and greenhouse gas emissions in this process.