METHOD FOR PROCESSING WASTEWATER CONTAINING FLUOROPHOSPHATE COMPOUNDS

PROBLEM TO BE SOLVED: To reduce the phosphorus concentration and fluorine concentration in wastewater occurring to a level such that it is possible to discharge into the sea or the like with little dilution, performing the reduction by means of an easy process and with little energy loss, when producing lithium hexafluorophosphate or an electrolyte resulting from dissolving lithium hexafluorophosphate in an organic solvent.SOLUTION: This method for processing wastewater containing fluorophosphate compound is characterized by having: a decomposition step decomposing fluorophosphate compounds by causing the inclusion of hydrogen chloride in the wastewater containing fluorophosphate compounds in a manner so that the concentration of hydrogen chloride becomes 11-25 mass%, and then heating the wastewater to 50°C or higher and lower than 80°C; an immobilizing step of immobilizing phosphorus and fluorine in the wastewater by adding a calcium compound to the wastewater after the decomposition step, causing the pH of the wastewater to be at least 6; and a solid-liquid separation step of obtaining wastewater with reduced concentration of fluorine and phosphorus by eliminating the solid material immobilized in the immobilizing step.