Abstract: The present invention pertains to electrolytic diaphragm cells, particularly for the electrolysis of brine to produce chlorine and caustic. The innovation resides generally in the discovery that electrolytic cell operation can be desirably enhanced by compressing the diaphragm between anode and cathode. This compression of the diaphragm reduces the diaphragm thickness from an original thickness, e.g., from an original thickness of a diaphragm freshly deposited on a cathode. The reduced thickness of the diaphragm provides for cell operation that is less than zero gap operation. By maintaining the diaphragm under compression and in a reduced thickness, the cell operates with a narrower interelectrode gap and consequently at a desirably reduced cell voltage.

Abstract: An apertured and porous metal article can find use, for example, in diaphragm or membrane electrolysis cells. The article may comprise a thin and flexible metal foam of small pores which, typically, has been perforated with large apertures. The article may also be provided with an electrocatalytic coating. It can be in substantial physical contact with a membrane or diaphragm separator used in the cell for separating anode and cathode members or compartments. There is also disclosed the preparation of the article and an electrolysis cell utilizing the resulting apertured and porous metal article.

Abstract: There is now disclosed a method of restoring a used article utilized in electrolysis, such as in a chlor-alkali cell. The used article is usually the cell diaphragm, but may be a cell electrode, particularly when it is in assembly with the cell diaphragm. The restoration method involves treating the article, typically in place in the cell, but which may be removed from the cell, by soaking in a treating composition containing most always hydrochloric acid and corrosion inhibitor. The article after treatment may be baked at elevated temperature. When baking is utilized, it can come before soaking. With or without baking, the article may or may not be involved in a wetting step. Where the restoration involves an article utilized in a chlor-alkali cell, the restoration can readily reduce the problem of hydrogen in the chlorine product produced. Such treatment can also lead to reduced cell voltage as well as reduced cell anolyte level.