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: The present invention resides in a process and apparatus for the electrolytic production of strong solutions of halogen oxyacids, more specifically for the production of such acids having a normality of about 0.1 to about 3.6 from the corresponding alkali metal salts of such acids. The present invention comprises establishing a solution of the corresponding alkali metal salt having a molar concentration less than that at which precipitation of said salt occurs. An electrolytic cell is provided comprising an anode compartment containing an anode, a cathode compartment containing a cathode, and a middle feed compartment intermediate the anode compartment and cathode compartment. The feed compartment is separated from the anode compartment by a diaphragm and from the cathode compartment by a cation-selective membrane. Means are provided for introducing said alkali metal salt solution into said middle feed compartment and for applying a voltage between the anode and cathode.

Abstract: A method and apparatus are disclosed for replenishing metal ions in an electrolyte depleted of the metal ions. A preferred example is replenishing tin in the electrolyte of an electrolytic tinning apparatus having an insoluble anode. The electrolyte thus becomes depleted of tin in the electrotinning process. The replenishment apparatus comprises an electrolytic cell including a tin anode, a cathode, and an electrolyte chamber for the tin anode and the cathode. The cathode is a gas diffusion electrode. An electrical circuit, usually having additional circuit resistance but free of connection to an external power source, connects the anode to the cathode. The electrolyte chamber has an electrolyte inlet, and an electrolyte outlet which is in flow communication with the electrolytic tinning apparatus. The gas diffusion electrode is exposed, on its gas side, to a source of gaseous reactant, e.g., oxygen.

Abstract: A highly magnetic isotropic iron oxide powder with a uniform particle size distribution and particle size in the range from 0.005 to 0.2 micrometer consists of a mixed iron oxide exhibiting gamma (Fe.sub.2 O.sub.3) and ferrite (Fe.sub.3 O.sub.4) structure, having the empirical formula Fe.sub.72-x O.sub.96, where x has a value between 2 to 7, an aspect ratio of at most 2:1 and a temperature coefficient of coercivity of less than -0.7% per degree Celcius. The mixed oxide is optionally a cobalt-modified mixed iron oxide containing 2-6% by weight of cobalt and is obtained by heating ultrafine, ferrite particles in a controlled, oxidizing atmosphere at a temperature of 240.degree. C. to 320.degree. C. for a period of one to three hours.

Abstract: An improved electrolytic cell for the electrolysis of alkali metal halide solutions to produce halides and alkali metal hydroxides is provided wherein current reductions are obtained by the passage of an oxidizing gas, such as oxygen, into a porous cathode to depolarize the cathode and eliminate the porduction of hydrogen. The cathode is provided with small diameter pores for diffusion of said oxidizing gas, and larger diameter pores or holes for liquid product flow through the cathode. The cathode, separator, and anode may be in direct contact with each other in a sandwich configuration, thus eliminating the need for a catholyte compartment and external H.sub.2 O feed lines.