Huron Chemicals Limited

Bruno Kindl

Harold Vincent Casson

Edward B Noonan

Richard Eric Loftfield

Grant G Crabtree

Jennifer Geraldine Atkinson

Substrates which are susceptible to corrosion by the action of chemical agents in gas-containing and/or gas-generating media are rendered resistant to said corrosion by the application thereto of a coating of a gas-permeable elastomeric or plastic material, and providing for means of escape of gases permeating the coating, thereby maintaining the adhesion of the coating to the substrate. Preferably the coating is applied first to a porous backing material such as woven glass cloth, so that the pores of the backing material are left substantially open to let gas escape. The laminate of coating and porous backing material is then adhesively secured to the substrate in such a way that the pores in the backing material are left partly open to let gas escape. The invention has particular application to the lining of electrolytic cells, cell tanks, submerged buswork, and associated equipment (except electrodes); and also to the lining of chemical process vessels, equipment, piping, valves and the like for use in the production and handling of chemicals.

Protection of substrates against corrosion

Substrates which are susceptible to corrosion by the action of chemical agents in gas-containing and/or gas-generating media are rendered resistant to said corrosion by the application thereto of a coating of a gas-permeable elastomeric or plastic material, and providing for means of escape of gases permeating the coating, thereby maintaining the adhesion of the coating to the substrate. Preferably the coating in applied first to a porous backing material such as woven glass cloth, so that the pores of the backing material are left substantially open to let gas escape. The laminate of coating and porous backing material is then adhesively secured to the substrate in such a way that the pores in the backing material are left partly open to let gas escape. The invention has particular application to the lining of electrolytic cells, cell tanks, submerged buswork, and associated equipment (except electrodes); and also to the lining of chemical process vessels, equipment, piping, valves and the like for use in the production and handling of chemicals.

Chromates are removed from aqueous alkali metal chlorate solutions by either of two processes. In the first process, a water-soluble sulfide is added to react with the chromate, and then a ferrous salt is added. The soluble sulfate is converted to elemental sulfur and the chromate is converted to an insoluble trivalent Cr-containing material which is removed from solution. In the second process an 'iron mud' is prepared by reacting a ferrous salt with sodium hydroxide and added so as to precipitate insoluble trivalent chromium-containing material.

Chromate removal by precipitation

An electrolytic cell is provided that is particularly suitable for the production of oxy -halogen compounds such as sodium chlorate by electrolysis of an alkali metal halide such as sodium chloride. A cell chamber is provided containing an electrode assembly and is connected for the circulation of electrolytic solution to a cooling and concentrating chamber. Gas communication between the cell chamber and the cooling and concentration chamber is substantially avoided. Gas evolved during the electrolysis is separately removed from the cell chamber and is preferably scrubbed. Gas such as air is swept through the cooling and concentration chamber so as to provide at least part of the cooling requirements for removing the heat generated during the electrolysis and to evaporate, thereby concentrating the electrolytic solution. This takes advantage of the sensible heat of the electrolytic solution for the evaporation of such solution.

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Kingston, Canada

Bruno Kindl