METHOD OF LEWISITE DETOXICATION Russian patent published in 2003 - IPC

FIELD: chemical technology of utilization of regular chemical warfare agents; applicable in destruction of lewisite resources in the Russian Federation. SUBSTANCE: method is based on use for lewisite detoxication of its decomposition with aqueous solution of sodium hydroxide with subsequent processing of formed suspension of arsenic-containing slime in water- alkali solution of arsenite and sodium chloride, with production of low-toxic and suitable for prolonged storage of dried residue of salts Na₃AsO₃ and NaCl resulting from evaporation and drying of said mixture, and allowing recovery of elementary arsenic from it as required. Lewisite is subjected to reaction with 20-40 wt.% aqueous solution of sodium hydroxide with 0.1-10 wt.% excess at 90- 110C and atmospheric pressure with subsequent processing of reaction mass by evaporation and drying at 74-125 C and pressure of 0.4-0.6 atm into salt residue of Na₃AsO₃ and NaCl obtained with help of additions of 8.0-15.0 wt.% of 1,1,2,2- tetrachloroethane and 0.5-1.0 wt.% of montmorillonite clay. Realization of claimed method on industrial scale allows ecologically safe destruction of lewisite resources in Russia. EFFECT: higher efficiency.