Abstract: The invention is a process for treating waste slurry generated in the electric furnace production of phosphorus in which a superatmospheric reactor is operated at an elevated temperature to destroy cyanides, phosphorus, and phosphides present in the waste. The process transforms wastes from the phosphorus electric furnace process into non-hazardous solid, liquid, and gaseous wastes that meet environmental regulatory requirements regarding solids for phosphorous, cyanide, phosphine and cyanide flux, and TCLP metals, and regarding the filtrate for UTS metals.