NOVELTY - A purifier (1) has cation exchange membrane (C1,C2) arranged between a cathode (2) and an anode (3), monovalent selective anion exchange membrane, a desalination chamber (4), a concentrate chamber (5), a purification hydraulic chamber (6), waste liquid supply flow channel (L1) for introducing fluoro nitric acid waste liquid (11) containing fluosilicic acid, an electrolyte solution transfer path (L2), a concentrate exhaust passage (L3), a purification liquid extraction path (L4), a cathode chamber (9) and an anode chamber (10).    USE - Purifier is used for purifying fluoro nitric acid waste liquid discharged during surface treatment and surface washing of silicon wafer for manufacture of solar cell.    ADVANTAGE - The fluosilicic acid contained in fluoro nitric acid waste liquid is efficiently removed without adding ion. The hydrofluoric acid and nitric acid are recovered efficiently with high concentration.    DETAILED DESCRIPTION - A purifier has cation exchange membrane (C1,C2) arranged between a cathode and an anode, monovalent selective anion exchange membrane (AS1,AS2) arranged between cation exchange membranes, a desalination chamber formed between anion exchange membranes, a concentrate chamber formed between membranes (C1,AS1), a purification hydraulic chamber (6) formed between membranes (C2,AS2), waste liquid supply flow channel for introducing fluoro nitric acid waste liquid containing fluosilicic acid to the desalination chamber, an electrolyte solution transfer path for transferring electrolyte solution to concentrate chamber from desalination chamber, a concentrate exhaust passage for taking out fluosilicic acid concentrate from concentrate chamber, a purification liquid extraction path for removing purification liquid (12) from chamber (6), a cathode chamber formed between cathode and membrane (C1), and an anode chamber formed between anode and membrane (AS2). An INDEPENDENT CLAIM is included for purification of fluoro nitric acid waste liquid, which involves introducing fluoro-nitric-acid waste liquid to desalination chamber, from waste liquid supply-flow channel, transferring electrolyte solution to concentrate chamber through electrolyte solution transfer path from desalination chamber, electrodialyzing by supplying with electricity between cathode and anode, taking fluosilicic acid concentrate from concentrate chamber through concentrate exhaust passage, and removing purification liquid from purification hydraulic chamber through purification liquid extraction path.    DESCRIPTION OF DRAWING(S) - The drawing shows the sectional view of purifier.    Purifier (1)    Cathode (2)    Anode (3)    Desalination chamber (4)    Concentrate chamber (5)    Purification hydraulic chamber (6)    Cathode chamber (9)    Anode chamber (10)    Fluoro nitric acid waste liquid (11)    Purification liquid (12)    Monovalent selective anion exchange membrane (AS1,AS2)    Cation exchange membrane (C1,C2)    Waste-liquid supply-flow channel (L1)    Electrolyte solution transfer path (L2)    Concentrate exhaust passage (L3)    Purification liquid extraction path (L4)