Study on the technology of preparing polyphosphoric acid by using purified wet-process phosphoric acid

Technology of preparing polyphosphoric acid with concentration and polymerization method was studied by using purified phosphoric acid as main raw material.Effects of feeding mode,stirring speed and temperature on polymerization degree of polyphosphoric acid were researched.The results indicated that products prepared under optimum conditions met the requirements of food-grade polyphosphoric acid.In addition,this method had the advantages of low cost,small pollution and low energy consumption.