Separation and Purification of Dimethyl Sulfone and Sodium Nitrate in Dimethyl Sulfoxide Industrial Waste Salt
A two-step crystallization method was used to realize the separation and purification of sodium nitrate and dimethyl sulfone in the waste salt,according to the solubility difference of sodium nitrate and dimethyl sulfone in aqueous solution with the change of temperature.In this paper,the effects of oxidation temperature,nitric acid concentration,number of times of application of mother liquor and the ratio of waste salt leaching water in solvent on the product were considered.The results showed that the oxidation temperature,nitric acid concentration and the number of times of applying the mother liquor have little effect on the product purity,and the mass fraction of waste salt leaching water in the solvent can not be above 50%,dimethyl sulfone could be effectively separated by cooling and crystallization at-3～-1℃,and sodium nitrate could be effectively separated by vacuum evaporation and concentration at 65～70℃.This process can make the recovery rate of dimethyl sulfone and sodium nitrate in waste salt reach 70.49%and 74.24%,respectively.
waste saltseparation and purificationdimethyl sulfonesodium nitrate
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