Method for treating alkaline waste liquid generated by synthesizing 4A molecular sieve from kaolin

The invention provides a method for treating alkaline waste liquid generated by synthesizing a 4A molecular sieve from kaolin, which comprises the following steps: adding kaolin and sodium hydroxide into the alkaline waste liquid generated by synthesizing the 4A molecular sieve from kaolin to form an initial material; introducing the obtained initial material into a colloid mill, and staying for a period of time to obtain molecular sieve mother liquor gel; transferring the molecular sieve mother liquor gel into a reaction kettle for crystallization reaction; and filtering and washing the turbid liquid after the reaction to obtain a filtrate which is a new round of alkaline waste liquid, and drying a filter cake to obtain the 4A molecular sieve. On the other hand, the invention provides a synthesis method of the 5A molecular sieve with stronger CO2 adsorption performance compared with the commercially available 5A molecular sieve, and the 4A molecular sieve obtained in the first aspect is subjected to ion exch