Method for recovering triethylamine, removing phosphorus pollutants and recovering phosphorus resources in glyphosate mother liquor

Abstract

A method for recovering triethylamine, removing phosphorus pollutants and recovering phosphorus resources in glyphosate mother liquor comprises operation steps as follows: (1) calcium hydroxide powder or a calcium hydroxide emulsion is added to the glyphosate mother liquor, the mixture is evenly mixed, the calcium hydroxide powder or the calcium hydroxide emulsion is required to be added to enable the pH value of the glyphosate mother liquor to range from 10.5 to 12.3, then the glyphosate mother liquor is heated to the temperature higher than 85 DEG C for a reaction for 0.5-3 h while stirring is performed, triethylamine vapor produced in the reaction is collected and condensed, and a triethylamine solution is obtained; (2) a solid-liquid mixture formed through the reaction is subjected to water vapor gas-stripping desorption, a gas discharged through water vapor gas-stripping desorption is condensed, and a triethylamine solution is obtained; (3) the triethylamine is obtained through dehydration treatment of the obtained triethylamine solutions; (4) a coagulant is added to the solid-liquid mixture obtained after water vapor gas-stripping desorption while stirring is performed, the mixture is evenly mixed, then solid-liquid separation is performed after a reaction while stirring is performed, obtained solid substances are used as the phosphorus resources to be recycled, and an obtained liquid is collected for further treatment.

Description

Technical field [0001] The invention belongs to the field of glyphosate mother liquor treatment, and relates to a method for removing phosphorus pollutants from the glyphosate mother liquor and recovering triethylamine and phosphorus resources. Background technique [0002] The mainstream process for glyphosate production in my country is the glycine method (also known as the alkyl ester method). After the synthesis reaction is completed, solid-liquid separation and extraction of glyphosate will produce a large amount of acidic mother liquor (pH<1.0). It contains about 24% of triethylamine hydrochloride, 1-3% of glyphosate, as well as increased glyphosate, methyl glyphosate, aminomethyl phosphoric acid, dimethyl phosphite, inorganic phosphate, etc. Since the mother liquor contains a large amount of organic phosphines and other pollutants, direct discharge into the environment will cause serious environmental problems. Before 2010, domestic enterprises basically used the method...

AI Technical Summary

Problems solved by technology

Though said method can improve triethylamine rate of recovery, reduce waste water amount, but there are following problems: 1. owing to adding calcium hydroxide aqueous solution in glyphosate acidic mother liquor and reacting at normal temperature, thereby be difficult to remove the phosphorus pollutant in mother liquor Transform as much as possible, still have higher concentration of phosphorus pollutants in the mother liquor; Poor, the escape rate of triethylamine is slow, so the distillation time is long, resulting in increased energy consumption

3. due to higher phosphorus pollutants are arranged in the glyphosate mother liquor after step (1) treatment, thereby if the mother liquor at the bottom of the distillation tower is reclaimed for preparing calcium hydroxide aqueous solution, the calcium oxide aqueous solution will contain phosphorus pollutants, Increase the content of phosphorus pollutants in the glyphosate mother liquor for subsequent treatment. If the mother liquor at the bottom of the distillation tower is subjected to solid-liquid separation to recover calcium chloride through distillation and dehydration, it will be difficult to obtain qualified calcium chloride products.