Sodium sulfate is not pure, often containing sulfuric acid and a small amount of inclusions; crystal is pure, but not strong composition of powder. Sodium sulfate powder every 100 minutes after the crystallization of sodium sulfate 227. They are soluble in water and glycerin and sodium sulfate, crystal more easily dissolved, it is in the air easily weathered, losing 10 crystal water molecules into white powder.

Ningbo sodium sulfate should be neutral, dissolved there shall be no solid residue, and should not contain any salt or magnesium salt, with the presence of chloride, only a trace. Ningbo sodium sulfate salty and bitter, it is a neutral sodium sulfate, which is a very stable salt, can withstand strong heat and the final decomposition; at temperatures below 888 DEG C remain solid, only at 888 ℃ melted into liquid.

Ningbo sodium sulfate used in the manufacture of sodium sulfide, sodium silicate, Qun Qing and other chemical products, used in the manufacture of kraft pulp and paper industry, glass industry used instead of soda ash, dye industry as filler. Printing and dyeing industry for help agent, used as a laxative and barium salt poisoning antidote, pharmaceutical industry. In addition, also is used in the manufacture of synthetic fiber, leather, non-ferrous metallurgy, enamel, soap and so on in the.

For direct dyes, sulfur dyes, vat dyes and indigosol dyes cotton, available Ningbo sodium sulfate as accelerating agent. These dyes are very easy to dissolve in the preparation of the dye solution, but not easy to dye cotton fiber. The dye is not easy to absorb water, foot residual dye lot. Join Ningbo sodium sulfate can decrease the solubility of dyes in water, thus increasing the color force dye. In this way, the amount of dyes can be reduced, and the dyed color deepening.

For application of direct dyes on protein fiber, silk dyeing, the dyeing fastness of acid dye is better than the general. Some direct dye has excellent dischargeability, so they in silk fabric printing, often as a discharge to color use.

Direct dyes dyeing silk also often add a small amount of Ningbo sodium sulfate, but Ningbo sodium sulfate here and dyed cotton is different, only plays the retarding agent.