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Your search keyword '"Dantas Neto, A.A."' showing total 20 results
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18. Effect of the extracting agent hydrocarbon chain size on tungsten extraction.

Author

Dantas Neto A.A., Chemical metallurgy Concepcion, Chile 20-Nov-9423-Nov-94, Dantas T.N.C., Silva L.P.M.A., Dantas Neto A.A., Chemical metallurgy Concepcion, Chile 20-Nov-9423-Nov-94, Dantas T.N.C., and Silva L.P.M.A.

Abstract

Tungsten was recovered from low-grade (0.17% WO3) scheelite wastes using, as extracting agents, long chain aliphatic amine salts which had been synthesised from their respective alcohols. The aqueous phase used for solvent extraction was produced by leaching the scheelite wastes with an EDTA alkaline solution. The organic phase contained the extracting amine salt, octanol modifier and kerosene diluent. The effects were evaluated of aqueous feeder pH, extractant concentration, contact time and the aqueous/organic volumetric ratio. The best results were 78% extraction at pH 5.5 using N,N-diethylbutylamine chloride, 90% extraction at pH 3.5 using N,N-diethyloctylamine chloride and 91% extraction at pH 3.5 for N,N-diethyldodecylamine chloride. An increase in the number of carbon atoms in the chain results in an increase in the percentage extraction., Tungsten was recovered from low-grade (0.17% WO3) scheelite wastes using, as extracting agents, long chain aliphatic amine salts which had been synthesised from their respective alcohols. The aqueous phase used for solvent extraction was produced by leaching the scheelite wastes with an EDTA alkaline solution. The organic phase contained the extracting amine salt, octanol modifier and kerosene diluent. The effects were evaluated of aqueous feeder pH, extractant concentration, contact time and the aqueous/organic volumetric ratio. The best results were 78% extraction at pH 5.5 using N,N-diethylbutylamine chloride, 90% extraction at pH 3.5 using N,N-diethyloctylamine chloride and 91% extraction at pH 3.5 for N,N-diethyldodecylamine chloride. An increase in the number of carbon atoms in the chain results in an increase in the percentage extraction.

Published
1994

20. Gallium extraction by microemulsions

Author

de Castro Dantas, T.N., de Lucena Neto, M.H., and Dantas Neto, A.A.

Subjects
*EMULSIONS, *EXTRACTION (Chemistry), *GALLIUM, *ALUMINUM
Abstract

In this work, the use of microemulsion in the extraction of gallium, with Bayer process, has been studied. The studied microemulsion systems were: systems I and II, with saponified coconut oil (SCO) and 4-ethyl,1-methyl,7-octyl,8-hydroxyquinoleine (Kelex-100) as extractants. The extraction essays by microemulsion were carried out by applying an experimental planning method whose microemulsion points were prepared within an experimental domain favorable to the extraction. Gallium and aluminum extraction percentages, in each point, were evaluated via a statistical treatment of the data, with the use of variance analysis and mathematical models. In system I (SCO), percentages of extraction of 85.5% for gallium and 35.4% for aluminum were achieved; in system II (Kelex-100), the yields were 100% for gallium and 99.9% for aluminum. The reextraction study with sulfuric acid presented the same behavior for both systems, with efficiency depending upon the concentration of the acid, and allowing for a selective reextraction of gallium and aluminum. [Copyright &y& Elsevier]

Published
2002
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