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US 4,291,009 AGranted
Catalytic process for the production of alkali metal stannates
AssigneeVulcan Materials Company
InventorJohn A. Franks, Jr.
Life of this patent
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Abstract
Tin salts, such as, for example, alkali metal stannates, are produced by contacting at elevated temperatures an aqueous alkaline solution, such as for example, alkali metal hydroxide solutions, with a tin-containing material in the presence of a reaction promotor comprising the combination of activated carbon and an oxygen supplying agent.
Claims12
A catalytic process for the production of alkali metal stannates, comprising the steps of:
- (a) contacting at a temperature between about 150.degree. and 235.degree. F. an aqueous alkali metal hydroxide solution with an excess of metallic tin in the presence of activated carbon in an amount of from about 1 to 15 percent by weight of said metallic tin;
- (b) passing a molecular oxygen supplying agent selected from the group consisting of oxygen and air through said solution in the presence of said metallic tin and said activated carbon at a rate sufficient to promote the conversion of said metallic tin to alkali metal stannate and to form an alkali metal stannate solution, said rate being sufficient to provide from about 0.02 to 0.4 liters of oxygen per minute per liter of solution;
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- (c) recovering the resulting alkali metal stannate solution.
1 more element
A catalytic process for the production of alkali metal stannates selected from the group consisting of sodium and potassium stannates, comprising the steps of:
- (a) intimately contacting an aqueous alkali metal hydroxide solution selected from the group consisting of sodium and potassium hydroxide solutions with an excess of metallic tin particles having a specific surface area of at least 0.1 cm.sup.2 /gram in the presence of activated carbon at a temperature of from about 150.degree. to about 235.degree. F. by feeding said alkali metal hydroxide solution downwardly through a bed of said metallic tin particles containing from about 1 to about 15 percent by weight of said activated carbon in an amount sufficient to immerse at least a portion of said bed;
- (b) simultaneously feeding a stream of molecular oxygen supplying agent selected from the group consisting of oxygen and air upwardly through said bed in countercurrent flow to said alkali metal hydroxide solution from the immersed portion of said bed to the upper portion of said bed at a rate sufficient to promote the conversion of said metallic tin to alkali metal stannate, said rate being sufficient to provide from about 0.02 to 0.4 liters of oxygen per minute per liter of solution, and for a time sufficient to produce an alkali metal stannate solution containing at least about 60 to about 80 grams stannate per liter of solution;
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- (c) recovering the resulting alkali metal stannate solution.
1 more element
Dependencies are inferred from the claim text.