Method for preparing sulphur black dye and sodium thiosulfate from sulphur dye waste water

Abstract

The invention relates to a method for preparing sulphur black dye and sodium thiosulfate from sulphur dye waste water, which comprises the following steps: heating sulphur dye waste water, then mixing the sulphur dye waste water with 2,4-dinitrochlorobenzol, adjusting the PH value of the mixed solution with alkali, and carrying hydrolysis reaction; mixing and stirring the sulphur dye waste water, the sodium thiosulfate and sulfur, and heating the mixture for carrying out polysulfide reaction; mixing the mixed solution of the hydrolysis reaction and the mixed solution of polysulfide reaction for sulfofication reaction, and after the reaction is finished, introducing air for oxidation reaction to obtain mixed mother solution; filtering the mixed mother solution to obtain sulphur black dye grains, and drying, grinding and blending the sulphur black dye grains to obtain commercial sulphur black dye grains; and condensing, decoloring, crystallizing, drying and screening the filtered mixed mother solution to obtain the sodium thiosulfate. The method can effectively treat sulphur dye waste water, not only solve the problem of sewage treatment, but also save large amount of clean water.

Description

technical field

[0001] The invention relates to a method for treating and comprehensively utilizing waste water from the production of chemical dyes, in particular to a method for preparing sulfur black dye and sodium thiosulfate by utilizing sulfur dye waste water. Background technique

[0002] At present, for the treatment of wastewater generated from the production of sulfur dyes (the wastewater mainly contains derivatives such as dye intermediates and 2,4-dinitrophenol sodium), basically a primary wastewater treatment system is used for neutralization, mixing Coagulation and sedimentation treatment, and then discharge the treated wastewater. If the dye intermediates remaining in the wastewater can be removed after the treatment reaches the standard, the COD at the outlet is below 100mg / l, which meets the national wastewater discharge requirements, but the wastewater treatment fee per ton is more than 50 yuan, which increases the production cost of sulfur dyes . If the ...