METHOD OF UTILIZATION OF LEWISITE WITH PRODUCTION OF METALLIC ARSENIC Russian patent published in 1995 - IPC

FIELD: chemical engineering. SUBSTANCE: preliminarily mixed gas-vapor mixture of hydrogen and lewisite at molar ratio of 2/1 to 9/1 at 800 to 1000 C is subjected to pyrolysis. Passing through a reaction device gas-vapor mixture decomposes mainly to metallic arsenic and hydrogen chloride. From the reaction device the mixture gets into a settling vessel, where metallic arsenic settles down on the vessel cold surface. Reaction of lewisite pyrolysis to metallic arsenic is a gas-phase reaction, whose rate depends on the temperature at which the process is being carried out and concentration of hydrogen in the starting gas-vapor mixture. The method provides for utilization of lewisite until at least 99.9% of theoretical yield of metallic arsenic is obtained; the process is accomplished in a single stage, concentration of lewisite at the outlet from the reaction device is below the critical limit of concentration of lewisite in air of the working zone of the production- floor area. EFFECT: facilitated procedure. 2 cl