Ppg Industries, Inc.

Colonel R Dilmore

Carl W Raetzsch

Donald W DuBois

Thomas C Jeffery

Hugh Cunningham

Bernard A Maloney

Henry W Rahn

John O Snodgrass

W Bruce Darlington

Dallas D Dupre, Iii

James J McGinley

Edsel V Hoover

Allan B Kriss

A method for preparing asbestos-free diaphragms for chlor-alkali electrolytic cells is described. The comprises establishing a liquid permeable diaphragm base mat of fibrous synthetic polymeric material and ion-exchange material on the cathode structure, treating the base mat with strongly alkaline aqueous alkali metal hydroxide having a concentration of from about 15 to about 40 weight percent, and providing a coating of inorganic particulate material on the base mat before the base mat has dried. Preferably, the base mat is coated with the inorganic particulate material using a slurry of the inorganic particulate material suspended in the strongly alkaline aqueous alkali metal hydroxide.

Method for preparing asbestos-free chlor-alkali diaphragm

Asbestos-free diaphragms for chlor-alkali electrolytic cells are prepared by establishing a liquid permeable diaphragm base mat of fibrous synthetic polymeric material on the cathode structure, providing a coating of inorganic particulate material on the base mat, and treating the coated base mat with a nonionic or anionic surfactant. Preferably, the base mat is coated with the inorganic particulate material using a slurry of the inorganic particulate material suspended in an alkali metal halide brine solution containing the surfactant.

Method for preparing diaphragm for use in chlor-alkali cells

A liquid permeable diaphragm for use in an electrolytic chlor-alkali cell, the diaphragm being made of fibrous material and having particulate zirconia deposited in the interstices of the fibrous matrix, prior to installing the diaphragm in the cell. Also described is a zirconia impregnated fibrous diaphragm having a zirconia topcoating applied to the anode face thereof.

Diaphragm for use in chlor-alkali cells

A liquid permeable diaphragm for use in an electrolytic chlor-akali cell, the diaphragm being made of fibrous material and having deposited thereon and cementitiously bonded to the anode face thereof at least one topcoating of inorganic, particulate, refractory material. The interstices of the fibrous matrix of the diaphragm may also have particulate zirconia deposited therein.

A non-asbestos, electrolyte permeable diaphragm fabricated of thermoplastic organic polymer material containing ion exchange functional groups or precursor groups thereof is disclosed. The diaphragm can be prepared by providing a slurry of the organic polymer material, depositing the organic polymer material upon a cathode substrate and treating the organic polymer material to secure a stable diaphragm.

Synthetic diaphragm and process of use thereof

Discloses a permionic membrane bipolar electrolyzer for the electroylsis of aqueous alkali metal chlorides. The electrolyzer is characterized by having a minimum anode to cathode gap, e.g., the anode and cathode both in contact with the permionic membrane, and by having means to prevent the diffusion of nascent hydrogen between adjacent electrolytic cells.

Bipolar electrolyzer

Discloses a method of operating a bipolar electrolyzer having a plurality of electrolytic cells hydraulically in parallel where the flow rate of electrolyte and effluent provides circulation, mixing, and avoids pressure transients.

Bipolar electrolyzer process

Disclosed is a bipolar electrolyzer having a plurality of individual electrolytic cells electrically and mechanically in series with a bipolar element between pairs of adjacent individual cells. The bipolar element has an anodic side with anodes of the first electrolytic cell of a pair of electrolytic cells depending therefrom, and a cathodic side with the cathodes of the second electrolytic cell of the pair of electrolytic cells depending therefrom. The anodic side of the bipolar element has an acidified alkali metal chloride resistant valve metal surface, and the cathodic side of the bipolar element has an alkali metal hydroxide resistant transition metal surface. The bipolar electrolyzer is characterized by the bipolar element having a bonded laminate of a valve metal and a transition metal, a first metal plate of a transition metal, intermittently bonded to the transition metal member of the bonded laminate at the first joints, and a second transition metal plate above the first joints, that is, above the joints between the first transition metal plate and the bonded laminate. The second metal plate is bonded to the first metal plate and second joints whereby to protect the first joints from contact with the catholyte liquor.

Bipolar electrolyzer element

Disclosed is a method of preparing a resin-containing asbestos diaphragm. The diaphragm is prepared by depositing asbestos fibers and resin from an aqueous slurry onto a liquid permeable cathode and subsequently heating the deposited asbestos fibers and resin to cause the resin to bond the asbestos fibers together. As disclosed, air flow is maintained through the diaphragm until the diaphragm is substantially free of entrained water. The heated air is maintained at a temperature below the boiling temperature of entrained water so as to avoid boiling the entrained water.Thereafter, the temperature of the deposited diaphragm is heated to cause the resin to bind the asbestos fibers together.

Method of preparing a resin-containing asbestos diaphragm

Disclosed is a bipolar electrolyzer having a horizontal hydrogen channel separate from the catholyte chamber. There are apertures between the horizontal hydrogen channel and the catholyte chamber to enable catholyte gas, i.e., hydrogen, with entrained cell liquor, to enter the channel. At one end of the channel is a gas disengaging chamber. The gas disengaging chamber includes a catholyte gas deflector interposed between the outlet of the horizontal channel and the interior of the disengaging chamber, hydrogen recovery means, and catholyte liquor recovery means. In the operation of an electrolytic cell as disclosed herein, catholyte gas, i.e., hydrogen gas with entrapped catholyte liquor, is removed from the catholyte chamber to the horizontal channel. The catholyte gas is then transported through the horizontal channel to the outlet of the horizontal channel and into the disengaging chamber. As the catholyte gas enters the disengaging chamber, its direction of flow is deflected while its linear velocity is reduced. The direction of flow of the gas is then reversed and the linear velocity reduced further, disengaging the catholyte liquor from the hydrogen. Finally, the hydrogen gas, substantially free of catholyte liquor, is recovered from the disengaging chamber.

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Jeannette, PA, United States of America

Colonel R Dilmore