Method for producing rongalite with low zinc

Abstract

This invention relates to a method for producing low-zinc rongalite. The method comprises: mixing water and zinc powder, beating, adding SO2, reacting to obtain zinc hydrosulfite, placing in a reaction pot, adding formaldehyde and zinc powder, reacting to obtain alkaline sodium formaldehyde sulfoxylate, precipitating, removing the supernatant, adding NaOH, reacting to obtain sodium formaldehyde sulfoxylate, filtering, standing for settlement, cooling, adjusting the pH value, performing ultrafiltration, mixing, adding NaOH, sending into an evaporator, evaporating to obtain melt of low-zinc sodium formaldehyde sulfoxylate, cooling, solidifying, and pulverizing to obtain the final product. The obtained low-zinc rongalite can satisfy the requirements of pharmaceutical and plastic industries. The zinc content is less than or equal to 50 ppm. The low-zinc rongalite has such advantages as high purity, high stability, low production cost and convenient usage.

Description

technical field

[0001] The invention relates to a method for producing low-zinc diabolites, belonging to the technical field of chemical industry. Background technique

[0002] Diaobaiku (sodium hydrogen sulfoxylate formaldehyde) is an important chemical raw material, which is widely used in synthetic rubber, printing and dyeing industries. At present, the preparation of sodium bisulfite formaldehyde (diamond block) is generally prepared by zinc powder-sulfur dioxide-formaldehyde method. It is made of zinc powder and water into a suspension, and sulfur dioxide gas is introduced to generate zinc dithionite. , adding zinc dithionite solution into formaldehyde solution to react, then adding zinc powder to generate basic zinc hydrogen sulfoxylate formaldehyde suspension, then adding sodium hydroxide solution to generate sodium hydrogen sulfoxylate formaldehyde solution, and then vacuum concentrating to obtain hyposulfuric acid Sodium hydrogen formaldehyde (Diaobai block) finish...

Images