A process for preparing ultra-clean high-purity ammonia water, comprising:
- (1) performing heating gasification, comprising:
- heating industrial grade ammonia water to evaporate into ammonia gas;
- (2) pressurizing the ammonia gas to remove impurities, comprising:
- pressurizing the ammonia gas obtained in step (1) to deposit organic impurifies, impurity metals, and particles existing in the ammonia gas to obtain pressurized ammonia gas;
- (3) washing the pressurized ammonia gas with ultrapure water to remove impurities, comprising:
- cooling the pressurized ammonia gas obtained in step (2) through a cooling tower to obtain cooled ammonia gas, and transporting the cooling ammonia gas to a washing tower containing ultrapure water to obtain ammonia water;
- and releasing high-purity ammonia gas from the washing tower when the ammonia water in the washing tower reaches saturation;
- (4) purifying the high-purity ammonia gas with a molecular sieve column, comprising:
- purifying the high-purity ammonia gas obtained in step (3) through an adsorption column filled with a molecular sieve to obtain purified ammonia gas;
- (5) absorbing the purified ammonia gas obtained in step (4) with the ultrapure water to obtain a product;
- and
- (6) filtering the product obtained in step (5) with an ultrafiltration membrane to obtain the ultra-clean high-purity ammonia water;
- wherein, in the step (2), conditions of the pressurizing comprise:
- a pressure of 0.3 megapascals (MPa) to 0.6 MPa, and a temperature of 10 Celsius degrees (° C.) to 20° C.;
- and
- wherein, in the step (4), the molecular sieve is a macroporous-microporous molecular sieve;
- a pore diameter of each macropore is in a range of 100 nanometers (nm) to 500 nm, a pore diameter of each micropore is in a range of 0.3 nm to 0.7 nm, and a specific surface area of the molecular sieve is in a range of 140 square meters per gram (m2/g) to 500 m2/g;
- and a process for preparing the molecular sieve comprises:
- mixing anhydrous ethanol and deionized water evenly at room temperature to obtain a mixed solution, adding ammonia water into the mixed solution, and stirring the mixed solution added with the ammonia water to obtain a stirred solution;
- adding tetraethyl orthosilicate dropwise into the stirred solution, and stirring the stirred solution added with the tetraethyl orthosilicate, followed by centrifuging and drying, to obtain silica microspheres;
- dispersing the silica microspheres in a mixed solution of a tetrapropylammonium hydroxide aqueous solution and anhydrous ethanol to obtain a dispersed solution, and performing ultrasound on the dispersed solution to obtain a mixed raw material;
- drying the mixed raw material to obtain a dry glue;
- and transferring the dry glue into a reactor with deionized water in a bottom, crystallizing the dry glue with steam assistance to obtain a crystallized dry glue, and taking out the crystallized dry glue, followed by washing, drying, and calcining in an air atmosphere, to obtain the macroporous-microporous molecular sieve.