TREATING METHOD FOR DESULFURIZED WASTE LIQUID

摘要

PURPOSE:To recover and reuse vanadium compound by returning it again to a desulfurizing process, by a method wherein a waste liquid obtained after gas containing H2S is desulfurized by the Stretford process is treated. CONSTITUTION:After gas 1 containing H2S is desulfurized by the use of redoxcatalyst, such as vanadium compound, anthraquinone disulfonic acid salt (ADA) etc., and alkali, it is calcined in a reducing atmosphere b to obtain an Na recovering liquid 4 and a reduction cracked gas 5. A tetravalent vanadium salt is contained in said Na recovering liquid, and thereby it is fed to a carbonation tank c whereat it is brought into contact with gaseous carbon dioxide and converted to carbonate or bricarbonate. Said recovering liquid 6 is further fed to an oxidation tank d whereat it is oxidized with air 9 under the existence of ADA and a chelating agent, and as a result, a tetravalent vanadium salt is changed to a pentavalent vanadium salt. Said pentavalent vanadium salt can be reused by the Stretford process for the desulfurization.