Preparation of Ferrophosphorus by Synergistic Reduction of Phosphate Rock and Copper Slag: Optimization of Carbon Addition

This is a theoretical and empirical investigation of the synergistic preparation of ferrophosphorus via carbothermal reduction using phosphate rock and copper slag as raw materials. The results showed that with an increase in carbon dosage, the amount of ferrophosphorus obtained first increased and then decreased. The amounts of ferrophosphorus obtained after separation were highest at a carbon dosage of 12 wt%. The distribution ratio of Fe–P in the slag and metal was opposite to that the amounts of ferrophosphorus, highlighting its facile and complete separation from the slag. A high carbon dosage also hinders the aggregation, growth, and separation of ferrophosphorus particles. In addition, the obtained ferrophosphorus impurity content is the lowest at a carbon dosage of 12 wt%. The products were characterized by X-ray diffraction, chemical composition and scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The main phases of the ferrophosphorus were Fe 3 P and Fe 2 P, and the main phase of the residue was CaSiO 3 . Graphical Abstract