Engelhard Minerals & Chemicals Corporation

Other

Engelhard Corporation

Robert C Langley

Muriel Abrash

Herbert Myers

An anode for use in electrolytic processes with an electrolyte containing sulfuric acid. The anode comprises a valve metal substrate, a lead or lead alloy antipassivation layer in contact with the valve metal substrate, and a lead ruthenate or lead iridate catalyst in surface contact with the lead or the lead alloy. Also disclosed are methods for employing the anode in electrowinning processes as well as a process for operating an electrolytic cell.

Titanium-lead anode for use in electrolytic processes employing sulfuric

Platinum and iridium in catalytic electrodes for electrochemical uses is partially replaced with lead ruthenate-tantalum oxide composite. Electrodes are fabricated by first coating a film-forming metal substrate with a platinum-iridium composite undercoat, then overcoating with a composite containing lead, ruthenium, tantalum, platinum, iridium and oxygen. The most preferred anodes have a titanium substrate initially coated with approximately at least 2 gm/m.sup.2 of 70:30 .sup.w /o Pt:Ir composite, followed by about 20 gm/m.sup.2 of a composite having the nominal composition of 22.2.sup.w /o Pb.sub.2 Ru.sub.2 O.sub.6 ; 66.6 .sup.w /o Ta.sub.2 O.sub.5 ; 7.9 .sup.w /o Pt and 3.4 .sup.w /o Ir. The outer layer of the prepared anode contains from about 10 to about 16 .sup.w /o lead, from about 40 to about 65 .sup.w /o tantalum, from about 5 to about 7.5 .sup.w /o ruthenium, from about 6.0 to about 10 .sup.w /o platinum, from about 2.5 to about 5 .sup.w /o iridium, and from about 10 to about 20 .sup.w /o oxygen. These electrodes may be used in acidic, neutral or alkaline solutions. Typical uses include production of chlorine and chlorine compounds and electrowinning of metals, such as zinc.

Promotion of Pt-Ir catalytic electrodes with lead, tantalum, ruthenium

An apparatus is disclosed for the electrolytic production of a solution of an aqueous alkali metal hypochlorite solution. The apparatus is especially useful for chlorinating swimming pools. The single vessel is partitioned horizontally into an upper compartment for the brine and a lower compartment serving as the electrolytic cell and provided with a removable electrode assembly with an electrode spacing of at least 0.5 inch. Brine feeds through and evolved gas emerges through the partition.

Apparatus for the production of aqueous alkali metal hypochlorite

Monolithic honeycomb structures are made by heating to a fluid condition an admixture comprising an inorganic powder and a temporary vehicle, forcing the fluid admixture through a stencil having a plurality of masking islands thereby forming a thin lamina beneath the stencil which is cooled immediately to form an essentially solid structure. This process is repeated to form a composite of successive cohered laminae thereby forming a monolithic honeycomb structure, which is heated to remove the vehicle and subsequently sintered to form a self-supporting honeycomb structure.

Method of making honeycomb structures

Thick film resistive elements are prepared from an intimate admixture comprising silica, lead oxide and ruthenium dioxide or iridium dioxide which is heated to a temperature sufficient to provide a lead-containing glass having dispersed therein lead ruthenate or lead iridate. The lead-containing glass is comminuted and a resistor paste is formed which can be subsequently coated and fired on to a desired substrate to form the thick film resistive component. The method of this invention may facilitate the production of thick film resistors exhibiting a low temperature coefficient of resistivity, relative freedom from noise and drift, and high moisture resistance.

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Millington, NJ, United States of America

Robert C Langley