Abstract: A crystallization system for producing sodium aluminum fluoride cryolite from hydrofluoric acid waste includes a crystallization reaction tank, a sodium aluminate tank, a high concentration hydrofluoric acid waste tank, a pH value/fluoride detecting section, a dehydrator, a low concentration hydrofluoric acid waste tank, and a control device. The crystallization reaction tank includes a dispersing plate and the control plate to control the flow rate and liquid form of the sodium aluminate and the hydrofluoric acid waste. The loop-like pH value/fluoride detecting section is in communication with the reaction tank to detect the pH value/fluoride concentration of the water sample which is the aqueous mixture of sodium aluminate and hydrofluoric acid waste. Therefore, the crystallization system is capable of controlling factors affecting the cryolite purity during the operation process, and consequently, the crystallization system can produce cryolite whose purity is good enough for recycling.

Abstract: A crystallization system for producing sodium aluminum fluoride cryolite from hydrofluoric acid waste includes a crystallization reaction tank, a sodium aluminate tank, a high concentration hydrofluoric acid waste tank, a pH value/fluoride detecting section, a dehydrator, a low concentration hydrofluoric acid waste tank, and a control device. The crystallization reaction tank includes a dispersing plate and the control plate to control the flow rate and liquid form of the sodium aluminate and the hydrofluoric acid waste. The loop-like pH value/fluoride detecting section is in communication with the reaction tank to detect the pH value/fluoride concentration of the water sample which is the aqueous mixture of sodium aluminate and hydrofluoric acid waste. Therefore, the crystallization system is capable of controlling factors affecting the cryolite purity during the operation process, and consequently, the crystallization system can produce cryolite whose purity is good enough for recycling.