Cominco, Ltd.

Shou C Liang

Horst E Hirsch

Robert F Redden

Thomas L Charlton

Cecil L Crossley

A method is described for attaching a preformed solder ring to a cover used to hermetically seal a container for a semiconductor device. The surface of the preformed solder ring that engages the cover is caused to melt and bond to the cover on solidification while the opposite surface of the ring is maintained relatively cool in a solid state by abutment against the flat surface of a cooling block.

Attachment of solder preform to a cover for a sealed container

Gallium and other values are recovered from phosphorus-furnace flue-dust by treating dust with sulfuric acid to form a solution and a residue. The residue may be treated for recovery of values. Zinc is precipitated from the solution as zinc ammonium sulfate hexahydrate and an alkaline material is added to precipitate a gallium concentrate and to form a gallium-free solution, which may be treated for recovery of sulfate and phosphate values. The gallium concentrate may be upgraded by mixing concentrate with lime to precipitate calcium phosphate and by subsequently adding sodium hydroxide to redissolve coprecipitated gallium and aluminum compounds. Residual precipitate is recycled and the solution is neutralized to precipitate an upgraded concentrate. Aluminum may be removed as calcium aluminate. Upgraded concentrate may be dissolved in alkaline solution and the solution electrolyzed for deposition and recovery of gallium.

Process for concentrating and recovering gallium

A process for producing gallium by electro-deposition from an acidic gallium chloride solution wherein electrolysis is conducted in the presence of metal ions of at least one metal from the group consisting of aluminium, zinc, calcium, magnesium, sodium and potassium dissolved in said solution.

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Spokane, WA, United States of America

Shou C Liang