Method for extracting sodium glycollate from CMC wastewater

Abstract

The invention relates to a method for extracting sodium glycollate from CMC wastewater. The method specifically comprises the following steps of extracting a mother solution, evaporating CMC salt-containing wastewater by utilization of an MVR evaporator, and removing 80 percent of inorganic salt to obtain organic matters with 10 to 15 percent of salt and 35 to 55 percent of moisture, thus obtaining the mother solution, wherein for 35 to 50 percent of the organic matters in the mother solution, 90 percent of the organic matters is sodium glycollate; adjusting the PH value of the mother solution to 10 by utilization of sodium hydroxide, filtering at a temperature about 60 DEG C while the mother solution is hot, and extracting from the solution by utilization of an ethanol solvent so as to obtain a crude sodium glycollate solid product; acidizing by utilization of sulfuric acid, taking the sulfuric acid as a catalyst, performing esterification by utilization of methanol so as to obtain methyl glycolate, and finally hydrolyzing and converting the methyl glycolate into a glycolic acid solution with a purity of 70 percent. The method disclosed by the invention has the advantages that the design is complete, the use is convenient, salt contents are effectively removed and a part of recycled water reaching industrial reuse water standards is produced after the CMC wastewater is treated, and residual concentrated wastewater is prepared into chemical products with a higher economic value through further chemical treatment.

Description

technical field [0001] The invention relates to the field of CMC wastewater treatment, in particular to a method for extracting sodium glycolate in CMC wastewater. Background technique [0002] Sodium carboxymethyl cellulose, referred to as CMC, is a carboxymethylated derivative of cellulose, also known as cellulose gum, and is the most important ionic cellulose gum. CMC was first produced in Germany in 1918, and was patented in 1921, and then commercialized in Europe. At that time, it was only crude product, used as colloid and binder. From 1936 to 1941, the research on the industrial application of CMC was quite active, and several enlightening patents were published. During World War II, Germany used CMC in synthetic detergents. The industrial production of CMC started in the 1930s at IG Farbenindustrie AG in Germany. Since then, the production process, production efficiency and product quality have gradually improved significantly. In 1947, the FDA of the United Sta...

AI Technical Summary

Problems solved by technology

For example, Japan adopts the hydrogen peroxide treatment process, and Germany adopts the resin exchange method, but they still have their own shortcomings and fail to achieve zero discharge of surface water.

my country has not yet seen mature technical patents in this area, and there is still a widening gap compared with developed countries