METHOD OF PROCESSING PRODUCTS OF ALKALINE HYDROLYSIS OF LEWISITE TO COMMERCIAL PRODUCT Russian patent published in 2010 - IPC A62D3/36 A62D3/37 A62D101/02 

FIELD: chemistry.

SUBSTANCE: invention relates to destruction of chemical weapons and more specifically to methods of processing reaction mass formed during a basic industrial process - alkaline hydrolysis of lewisite. In the method which involves dissolving lewisite reaction mass in liquid form, filtration, closed cycle processing, reduction of arsenic (V) compounds to arsenic (III) and obtaining arsenic (III) oxide and sodium chloride, the reaction mass is dissolved in hydrochloric acid solution to pH of the system equal to 8.0-9.0; the heterogeneous system obtained after dissolving is filtered and a solid adsorbent is added to the separated homogeneous filtrate to remove water-soluble organic compounds; after that the system is filtered again and lithium compounds are added to the obtained filtrate and the lithium arsenate precipitate formed is filtered and then converted to arsenic acid using hydrochloric acid and reduced via combined reduction to arsenic trichloride; after removal of lithium arsenate, the filtrate is evaporated, creating concentration of sodium dihydroarsenite in the solution equal to 25.0-30.0 wt %; the concentrate is neutralised with an acidic solution of arsenic trichloride to obtain an arsenic (III) oxide precipitate which is separated from the filtrate, sodium chloride which is extracted during hydrochloric treatment of the reaction mass, washed from adsorbed arsenic compounds, dissolved in water to obtain a solution which is purified chemically and using an adsorption technique.

EFFECT: increased efficiency of the method due to formation of a liquid phase composition for dissolving hydrolysed sodium arsenite, extraction of impurities of water-soluble organic compounds from the composition of the reaction mass, acceleration of the process of formation and ageing of the arsenic (III) oxide precipitate; increased degree of purity of sodium chloride solution from arsenic compounds.

10 cl, 1 dwg