A Sulfuric-Acid-Free Route from Phosphate Fertilizer By-Product Fluorosilicic Acid to UP-SSS Grade Electronic Hydrofluoric Acid: Process Theory

This preprint presents an independent complete-process theoretical framework for producing UP-SSS grade electronic hydrofluoric acid from phosphate fertilizer by-product fluorosilicic acid, completely circumventing all existing fluorspar-sulfuric acid patents. The route employs gas-phase ammonia ammonolysis, two-stage vacuum pyrolysis to directly crack ammonium bifluoride into anhydrous hydrogen fluoride, NF₃ gas-phase oxidation for impurity removal, and a reversed purification sequence featuring molecular distillation followed by sintered AlF₃-MgF₂ composite inorganic adsorbent. The process uses no sulfuric acid throughout. A corresponding invention patent has been filed with CNIPA (CN202610879885.X). This preprint establishes academic priority. The full technical report with detailed process parameters, equipment specifications, patent drafting guidelines, and cost model is available upon request to the author.