Process method for recycling and reusing hydrofluoric acid waste liquid (III)

The present invention relates to a process method for recycling and reusing hydrofluoric acid waste liquid (III), including: analyzing silicon content in hydrofluoric acid waste liquid; adding a postassium-containing compound whose quantity is more than two times higher than silicon quantity into the hydrofluoric acid waste liquid in a processing tank to make fluorine and silicon in hydrofluoric acid waste liquid and potassium carry out bonding reaction for producing potassium fluorosilicate solid; extracting supernatant after precipitating potassium fluorosilicate solid and adding high concentration hydrofluoric acid solution to meet the concentration of hydrofluoric acid solution used in the original process, thereby capable of being delivered back original process for reuse. This process method can prepare reusable hydrofluoric acid by only adding a few potassium ions into hydrofluoric acid waste liquid without consuming too much chemical agent, thereby greatly reducing discharge of waste water, saving the