The document summarizes the manufacturing of phosphoric acid using the electric furnace method. Key raw materials include phosphate rock, sand, coke, and briquette binder. In the reaction, calcium phosphate reacts with silica and coke at high temperatures to form phosphorus. The phosphorus then reacts with carbon monoxide and oxygen to form phosphorus pentoxide, which reacts with water to yield 85-90% phosphoric acid. The process uses phosphate rock, sand, and coke to produce phosphoric acid through high temperature reactions in an electric furnace.