Abstract: The present disclosure provides a method for cleaning a chlorine membrane electrochemical cell.

Abstract: A pressurized or forced circulation electrolysis cell comprising a cell housing containing at least one pair of electrodes which is a cathode and an anode, a current collector and an ion exchange membrane having a surface area of at least about 40 ft.sup.2 having the improvement which comprises an electrically conductive, hydraulically permeable resilient mattress substantially coplanar with and contacting on one side the current collector and coplanar with and contacting on the other side an electrode. The mattress comprises at least six non-aligned layers of woven and crimped metal fibers having a resiliency product of greater than 100 (inches).sup.2 /psi according to the formula:RP=10,000.times.NS.times.CHwherein RP represents the resiliency product in (inches).sup.2 /psi, NS is the negative slope of the mattress height versus compressive load of the mattress, and CH is the compressive height over the range that the mattress will be compressed in millimeters.

Abstract: Methods are disclosed to control reverse current flow in stacks of membrane electrolytic cells during off-line periods. One method includes the introduction of a stripping gas flow to the anolyte solution of the cells during an interruption of normal positive current flow. In another embodiment, reverse current flow is controlled by introducing at least one soluble reducing agent to the anolyte solution during an interruption of normal positive current flow. Also disclosed is a porous sparging apparatus useful in introducing a stripping gas flow to a stack of membrane electrolytic cells.

Abstract: The invention is a dampening device for use in a vertically disposed electrochemical cell unit of the type at least having: (a) a peripheral flange which defines at least one electrode chamber, said peripheral flange having a upper, substantially horizontally disposed flange portion, a lower substantially horizontally disposed flange portion, and two disposed side flange portions; and (b) at least one outlet port passing through the upper horizontally disposed flange portion or through one of the two vertical side flange portions or through the lower flange portion and connecting the exterior of the cell with the electrode chamber.

Abstract: Hardness values (Ca.sup.++ and Mg.sup.++) and other polyvalent metal cations are removed from alkali metal brines (esp. NaCl) by using a high surface area ethylene/carboxylic acid polymer (esp. porous ethylene/acrylic acid copolymers).

Abstract: Used or contaminated pieces of fluoropolymer membrane or sheet materials are salvaged for re-use by particulating the materials into powders, granules, or fibers, or otherwise reforming it, treating the particulated material, as desired, to cleanse or modify the material, and utilizing the material in subsequent applications.

Abstract: Method for reducing electrical energy consumption increase of ion-exchange membranes over long term use which comprises electrolyzing an alkali metal chloride solution which contains no more than about 75 ppm "carbonate" whether such low "carbonate" solution is achieved by removing excess carbonate previously added to the solution to reduce the hardness or not.

Abstract: Methods of membrane regeneration of permselective ion-exchange membranes of a brine electrolysis cell are greatly improved when the cells are fed brine which contains little or no carbon dioxide, carbonate anions or bicarbonate anions during normal electrolysis and when the methods of membrane regeneration are those wherein at least one liquid solution contacts the membrane and the pH of that solution is below that of the pH of the electrolyte in contact with the membrane during normal electrolysis.

Abstract: Electrolytic cell ion-exchange membranes, comprising fluoropolymers having pendant sulfonic acid functional groups and/or carboxylic acid functional groups, are treated with primary, secondary, and/or tertiary amines to provide dimensional stability and other improvements to the membranes. The treatment with amines provides easily-disassociable amines salts which are leached out by an aqueous leachant, e.g., cell electrolyte, thereby providing sulfonic acid groups and/or carboxylic acid groups to function as ion exchange sites in the membrane during subsequent cell operation.

Abstract: Improvements in electrolytic chlor-alkali membrane cells, operated with cell-to-cell catholyte series flow, are obtained by the use, as membranes, of fluoropolymers containing pendant functional groups on the cathode side which are less hydrophilic than sulfonic acid groups. Preferably the functional groups on the catholyte side of the membrane absorb about 5 to about 12 moles of H.sub.2 O per functional group whereas the functional groups on the anolyte side of the membrane absorb more, generally, about 15 to about 30 moles of H.sub.2 O per functional group.