Abstract: Mined salt mixtures comprising sodium-carbonate, -bicarbonate, -chloride, -sulfate, and -double salts, such as trona and burkeite, are leached with a bicarbonate-saturated solution and added carbon dioxide to selectively dissolve the sodium chloride, sodium sulfate and burkeite and to precipitate additional trona, leaving a leach residue consisting essentially of trona. The trona is calcined and dissolved, and the carbonate solution is purified, crystallized and dehydrated in a non-convective solar pond yielding high purity sodium carbonate monohydrate which is converted into dense soda ash. The brine solution from the leach may be treated for the recovery of a further amount of trona.

Abstract: A process is described for the removal of chloride impurity from zinc sulphate solution. The process comprises the steps of forming a slurry of said solution with an inert particulate support material having elemental silver dispersed thereon, and an oxidizing agent, agitating said slurry at a temperature between about 60.degree. and about 100.degree. C. for precipitation of silver chloride on said support material, filtering said slurry to separate purified zinc sulphate solution from the support material containing the precipitated silver chloride, and treating said separated support material containing precipitated silver chloride with a reductant in an aqueous alkaline medium to regenerate elemental silver on said support material.

Abstract: A seal for a terminal member of a nickel-cadmium battery cell, provided with a, for example Ceramvar, terminal electrode which is first of all electroplated with nickel and is then electroplated with chromium. A ceramic ring is located between the terminal electrode and a shoulder portion of a steel collar in the battery, the shoulder portion having an axial length greater than the axial length of the ceramic ring and the ceramic ring being brazed to the central region of the shoulder portion. Glass rings, for example, which may be transparent, are provided on opposite sides of the ceramic ring and rest on ledges of the shoulder portion whereby a respective void is formed between the glass ring and the respective adjacent surface of the ceramic ring.