Fmc Corporation

James Carmichael

James L Manganaro

Martin E Sacks

Harry M Castrantas

Craig W Rautiola

This invention relates to a process for producing Caro's acid by reaction of at least 85% by weight sulfuric acid and at least 50% by weight hydrogen peroxide wherein the sulfuric acid and hydrogen peroxide are fed through separate feed lines into a funneling zone open to the atmosphere, the feed lines having air gaps between their ends and the funneling zone; passing said hydrogen peroxide and sulfuric acid by gravity flow from said funneling zone into one end of a reaction zone whose size permits a pressure drop which is at least 8 times the theoretical pressure drop for such reaction zone and removing a mixture containing Caro's acid from the exit end of the reaction zone.

Method for producing caro's acid

This invention relates to a process for producing Caro's acid by reaction of at least 85% by weight sulfuric acid and at least 50% by weight hydrogen peroxide wherein the sulfuric acid and hydrogen peroxide are fed through separate feed lines into a funneling zone open to the atmosphere, the feed lines having air gaps between their ends and the funneling zone; continuing to introduce the sulfuric acid and the hydrogen peroxide into the funneling zone to flow and mix within the funneling zone, passing the resulting mixture by gravity flow into one end of a reaction zone whose size permits a pressure drop which is at least 8 times the theoretical pressure drop for such reaction zone and removing a mixture containing Caro's acid from the exit end of the reaction zone.

Method for producing Caro's acid

A process for treating effluents, such as precious metal tailings, having a pH of at least 9 and containing cyanide is described in which Caro's acid is added to the effluent having a pH of at least 9 and commencing the reaction of the cyanide with Caro's acid at 0.degree. C. to 80.degree. C. in the absence of an added alkali; adding sufficient Caro's acid within a mole ratio of Caro's acid to cyanide of 0.3/1 to 3/1 to reduce the pH of the effluent to below 9, continuing the reaction between Caro's acid and the cyanide to reduce the amount of cyanide remaining in the effluent and to recover an environmentally compatible effluent reduced in amounts of cyanide.

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Buffalo, NY, United States of America

James Carmichael