Ppg Industries, Inc.

Ppg Industries Canada Ltd.

William B Darlington

Donald W DuBois

Donald W Du Bois

William W Carlin

Malcolm Korach

Hugh Cunningham

Preston S White

Charles H Hoelscher

Robbie T Foster

John D Driskill

Carl W Raetzch

Richard J Blanchfield

Robert Cote

Michael A Wolanyk

Roseanne M Woo

The present invention relates to a method of removing ink from secondary fiber by contacting a pulp of said secondary fiber with an aqueous medium in the presence of a polymeric material having a glass transition temperature in the range of from about 20.degree. C. to about 70.degree. C. and a substituted polyethylene oxide to agglomerate the ink into discrete masses and separating the agglomerated ink from the pulp-containing aqueous medium.

Method for deinking wastepaper using alkoxy capped polyethylene oxide

Method for deinking wastepaper with a halogenated polyethylene oxide and

A method is disclosed for achieving additional bleaching of a wood pulp following a peroxide bleaching of the pulp, the method involving added thiourea to the slurry at a pH of 4 to 7 in the presence of residual peroxide and thereafter maintaining the slurry at a pH of 8 to 11.

Method for brightening pulp

Disclosed is a process of producing anhydrous sodium dithionite by contacting sulfur dioxide-containing formamide and sodium amalgam, separating a sodium dithionite-containing formamide solution from the sodium amalgam and precipitating anhydrous sodium dithionite from the product formamide solution by mixing the sodium dithionite-containing formamide solution with isopropanol, n-propanol, gamma-butyrolactone, tetrahydrofuran or N-methyl-2-pyrrolidone. The sulfur dioxide may be contacted countercurrently with the sodium amalgam in a continuous process. A neutralizing agent can optionally be added to the sodium dithionite-containing formamide solution separated from the amalgam to reduce acidic decomposition of the sodium dithionite.

Method for producing sodium dithionite

Disclosed is a solid polymer electrolyte electrolytic cell, e.g., for chlorine production, where the electrodes are in compressive contact with and removable from the permionic membrane.

Solid polymer electrolyte chlor-alkali electrolytic cell

Disclosed is a solid polymer electrolyte electrolytic cell, e.g., for chlorine production, where the electrodes are in compressive contact with and removable from the permionic membrane. For a preferred exemplification the anode is in compressive contact with and removable from the permionic membrane, and the cathode is bonded to the permionic membrane.

Solid polymer electrolyte chlor-alkali process and electrolytic cell

Disclosed is an electrolytic cell having an anode and cathode separated by and in contact with a permionic membrane. The cathodic surface of the permionic membrane is characterized by microporous channels of permionic membrane material extending from the surface into the membrane. Also disclosed is a method of electrolysis using the membrane and a method of preparing the membrane.

Permionic membrane

Solid polymer electrolyte chlor-alkali process

Disclosed is a solid polymer electrolyte electrolytic cell where the cathodic reaction takes place at a three phase catholyte-cathode catalyst-permionic membrane interface. The structure to carry this out may have electroconductive but electrolytically inactive portions of the cathode bonded to and embedded in the solid polymer electrolyte, and electrolytically active portions of the cathode extending outward from the permionic membrane into the catholyte. Alternatively, the cathode may compressively bear on a gel of permionic membrane material. Preferably the electrolytically active portions of the cathode extend out to about 1000 Angstroms into the catholyte, whereby to maintain the electrolysis within about 1000 Angstroms of the permionic membrane. The formation of hydroxyl ion within the permionic membrane is substantially avoided.

Electrolytically producing chlorine using a solid polymer

Disclosed is a solid polymer electrolyte having means for maintaining the interior of the solid polymer electrolyte wetted. This is to prevent salt crystallization within the solid polymer electrolyte. Also disclosed is a solid polymer electrolyte having the anodic surface thereof rendered hydrophobic by cross-linking. Additionally disclosed is the operation of a solid polymer electrolyte with a high purity, e.g., a brine containing less than 20 parts per billion calcium and 20 parts per million iron.

Solid polymer electrolyte chlor-alkali electrolysis cell

Disclosed is an electrolytic cell having an anode, a cathode, and a synthetic fluoro-carbon-resin permionic membrane between the anode and cathode. The improvement is characterized by the fluorocarbon-resin permionic membrane being a fluorinated copolymer having carboxylic acid ion exchange groups and the cathode having a catalytic, non-ferrous surface. Also disclosed is a process of producing an alkali metal hydroxide by electrolyzing an aqueous alkali metal chloride brine in an electrolytic cell having the anode separated from a catalytic, non-ferrous cathode by a synthetic fluorocarbon-resin permionic membrane having carboxylic acid ion exchange groups.

Electrolytic process and apparatus

Disclosed is a method of electrolyzing an alkali metal chloride brine in an electrolytic cell by feeding an aqueous alkali metal chloride brine containing less than 20 parts per billion dissolved alkaline earth metal ions, e.g., calcium, to the anolyte compartment of an electrolytic cell. Also disclosed is an alkali metal chloride brine containing less than 20 parts per billion of alkaline earth metal ions, e.g., calcium ion. There is also disclosed a method of purifying alkaline earth metal-containing brines, e.g., calcium-containing brines, by maintaining the brine alkaline, adding a phosphate to the alkaline brine whereby to form a calcium compound substantially insoluble in brine and thereafter separating the compound from the brine.

Removal of part per billion level hardness impurities from alkali metal

Disclosed is an electrolytic cell having electrode units of opposite polarity where each of the electrode units have fingered electrodes extending outwardly therefrom toward the electrode unit of opposite polarity. In this way, the electrodes are interleaved between electrodes of opposite polarity. At least one of the electrode units has a base plate with fingered electrodes mechanically and electrically connected thereto. The fingered electrodes bear a synthetic separator such as a microporous diaphragm or a permionic membrane thereon with lap at the base. The electrolytic cell is characterized by a fingered, interleaved electrode of the electrode unit of opposite polarity compressively bearing upon the lap, whereby to provide an electrolyte-tight seal.

Electrolytic cell membrane sealing means

Disclosed is a method of bonding two fluoropolymer membrane sheets. According to the disclosed method, a third sheet is contacted with a base and then interposed between the two membrane sheets. The two membrane sheets may also be contacted with a strong base. The resulting sandwich of three sheets is heated and pressed to effect the bond.

Growing community of inventors

Portland, TX, United States of America

William B Darlington