Process for the production of hydrogen fluoride, phosphoric anhydride,

Abstract

A process for the production of hydrogen fluoride, phosphoric anhydride, calcium polyphosphates and nitric acid, is disclosed, characterized in that natural phosphate is heated by a plasma stream of working gas in the presence of water vapors to form hydrogen fluoride which is recovered as a commercial product. Then the thus defluorinated phosphate is further heated by an air plasma stream having a bulk temperature of at least 3,500.degree. K. and containing nitrogen oxides. Under such conditions, the defluorinated phosphate decomposes to form phosphoric anhydride and calcium oxide. The gas stream carrying the phosphoric anhydride, the calcium oxide and the nitrogen oxides is cooled down to yield, as commercial products, either phosphoric anhydride and nitric acid, or calcium polyphosphates containing up to 70% P.sub.2 O.sub.5 and nitric acid, or else all of the three products, depending on the cooling conditions. The advantages of the proposed process are as follows: High rate of the process, High concentration of hydrogen fluoride in the gas, and The possibility of simultaneously producing a range of products from cheap raw material while avoiding the use of other commercial products as feedstock for the process.