GB1335941A - Method of decreasing the impurity content of solutions by electrolysis - Google Patents

Abstract

1335941 Electrolytic cell for purifying electrolyte HOOKER CHEMICAL CORP 14 April 1972 [14 April 1971(5)] 17362/72 Heading C7B An electrolyte solution containing, as impurity, at least one metallic material (metal compound or free metal, ) e.g. up to 10% of Hg, Pb, Cr, Cu, Cd or Zn, phenolic material, e.g. up to 10% of phenol, mono-, di-or trichlorophenol, or 3, 4, 5- trimethyl phenol, or material providing cyanide ions, e.g. up to 5%, is electrolysed in an electrolytic cell containing at least one cathode and one anode, and a bed of particles of porosity 40 to 80% distributed in the solution e.g. by the flow of the solution through the cell preferably at a velocity of 0À5 to 100 cm/sec, to decrease its impurity content. The solution may also contain other impurities such as chlorinated organic compounds, chlorine, HCI, hypochlorites or hypochlorous acid, sulphate, fluoride, silicofluoride or phosphate; and support electrolytes such as borates, ammonia, NaCl, CaCl 2 , H 2 SO 4 , NaCN, NaOH, NaHCO 3 , HCl or chloroacetates. The particles may be of graphite or metal, or have a metallic surface, e.g. of Ru, Pt, Cu, Ag or Zn, or conductive metal compound, e.g. Fe-P, carbide, boride or nitride of Ta, Ti or Zr, PbO 2 or RuO 2 ; or the particles may be non- or semi-conductive, e.g. (PTFE coated) glass beads, polystyrene spheres, sand, fly ash, oxidised Fe-P, ZrO 2 or Al 2 O 3 . The electrodes may be of graphite, Pt or Ir deposited on Ti or Ta base metal, PbO 2 , MnO 2 , RuO 2 , Co, Ni, Cu, W bronze, or nitride or boride of Ta, Ti or Zr. The cell maybe of polyacrylate, polymethacrylate, polytetrahaloethylene, polypropylene, rubber, concrete, iron or steel, and operated under sub-or super-atmospheric pressure. The electrodes may be separated by a diaphragm of PTFE, coated screen, fiberglass, asbestos or porous ceramic. The electrolyte may be recirculated.