Diluted tributyl phosphate as an extractant for beryllium as its thiocyanate complex

Abstract

50% Tributyl phosphate-toluene was used for the quantitative extraction of beryllium from 0.5M hydrochloric acid containing 5M ammonium thiocyanate. Beryllium was stripped from the organic phase with 1M sodium hydroxide and determined colorimetrically at 510 nm as its complex with Eriochrome Cyanine R.Although several extractants are available for the solvent extraction of beryllium, they have only limited applications (1) . The d-diketones had no special advantages (2). Diethyl ether was used in fluoride (3) and thiocyanate (4) media but the extraction was incomplete. Trioctylamine in methyl isobutyl ketone (5) was used for its separation from acidic solutions.Tributyl phosphate (6) was used for the extraction of beryllium but the method had no practical utility as the extraction was possible only from 0.1M hydrochloric acid and 14M lithium chloride. Further, the extraction was not quantitative. A similar attempt was made to use tributyl phosphate as an extractant (7) in the presence of salicylic acid with no advantage.Many transition elements were extracted as their thiocyanate complexes with tributyl phosphate as the extractant(2) . Sekine (8) extracted americium from 5M sodium thiocyanate with 5% tributyl phosphate in hexane. Similarly, De and Sen (9) utilized the thiocyanate system for the solvent extraction of some transition elements such as cobalt, copper, and iron with tributyl phosphate.An attempt was made to extract beryllium from thiocyanate media with 50% tributyl phosphate, using toluene as the diluent. This paper describes such a method for the solvent extraction of beryllium. The method proposed is simple, rapid, selective, and applicable at microgram concentrations. The procedure was extended for the analysis of beryllium in beryl. EXPERIMENTALApparatus and Reagents. A Spektromom 204 spectrophotometer with 10-mm matched quartz cells, a Type FEK-57 photoelectric filter photometer, and Cambridge pH meter with glass and calomel electrodes were used.The tributyl phosphate, bp 143 °C, was from British Drug House, England (BDH). About 1.241 grams of beryllium nitrate tetrahydrate (BDH Ana-laR) was dissolved in 100 ml of distilled water containing 1 ml of nitric acid. The solution was standardized gravimetrically (10). It contained 0.545 mg/ml of beryllium. The diluted solution containing 5.45 Mg/ml of beryllium was prepared from stock solution by appropriate dilution.Eriochrome Cyanine R. (E. Merck, Germany) was an 0.1% a ueous solution.General Procedure. An aliquot of the solution containing 10.9 Mg of beryllium was taken. Then enough hydrochloric acid and ammonium thiocyanate were added to make their concentrations 0.5M and 5M, respectively, in a total volume of 25 ml. The sample was then transferred to a separatory funnel and extracted with 10 ml of 50% tributyl phosphate in toluene for 5 minutes at room temperature. The two layers were allowed to settle and separate.Beryllium was stripped from the organic phase by shaking it twice with 15 ml of 1M sodium hydroxide. To the aqueous phase, 3 ml of con...

Solvent extraction of beryllium from malonate solutions with liquid anion exchangers

“…This showed the optimum period of equilibration as 5 min. The existing methods needed a much higher period of shaking for quantitative extraction (2).…”

“…Beryllium has been extracted with /3-diketones (1) with no special advantages, and the extraction with diethyl ether or tributyl phosphate (2) from thiocyanate media was not selective. Throughout the extraction studies, the use of liquid anion exchangers from the organic acids is extremely limited.…”

Nonferrous metallurgy-light metals: aluminum, beryllium, titanium, and magnesium

“…Matsubara (171,172) determined Be in beryl and Be-Cu alloy based on the formation of the peroxotitanium complex by the reaction of beryllium with a reagent composed of Na2TiFe, NaF, and H2O2 in a molar ratio of 1:4:1. Kalyanaraman and Khopkar (127) determined Be in beryl photometrically with Eriochrome Cyanine R after extraction of the thiocyanate complex with 50% tributyl phosphate in toluene.…”