Studies on the extraction of chromium(VI) by ketones

A study of the extraction of chromium(VI) from aqueous media by ketones was made. Extraction of chromium was found to be most efficient from aqueous hydrochloric acid solutions. A mechanism for the extraction of chromium(VI) from aqueous hydrochloric acid solutions by methyl isobutyl ketone is proposed involving the formation of a receptor in the organic phase, the exchange of the chloride ion of the receptor for the anionic chromium(VI) species of the aqueous phase, and the solvation of the extracted chromium species. The differences in the abilities of various ketones to extract chromium(VI) from aqueous hydrochloric acid solutions, and the differences in the extraction of chromium (VI) from various aqueous acids by methyl isobutyl ketone are attributed to the differences in the formation of receptors.     

Studies on the extraction and determination of metal salts with isobutyl methyl ketone-XIII Extraction of thorium and uranium

The work deals with the extraction of thorium or uranium from hydrochloric, perchloric, sulphuric or nitric acid solutions of various concentrations, or from mixed acid solutions, by means of isobutyl methyl ketone. When the extraction is made from 5-8M hydrochloric acid that is 10M in lithium chloride or from 7-8M hydrochloric acid that is 1M in magnesium chloride, uranium is extracted quantitatively (>99%), whereas thorium is hardly extracted at all.     

Studies on the extraction and determination of metal salts with isobutyl methyl ketone-XIV Extraction of gold

The isobutyl methyl ketone extraction of gold(III) from hydrochloric acid or various mixtures of hydrochloric and other mineral acids was studied as a function of the gold concentration and the acid concentration. Gold (initial concentration up to 5 x 10(-3)M) was quantitatively extracted (99%) from 3-5M hydrochloric acid. Addition of nitric acid in 1-5M concentration and sulphuric or perchloric acid in 1-3N concentration to the 1-5M hydrochloric acid solutions used had no effect.     

The group extraction of noble metals with s-(1-decyl)-N,N'-diphenylisothiouronium bromide and their determination in the organic extract by atomic-absorption spectrometry

The distribution coefficients are given for the noble metals and associated base metals between S-(1-decyI)-N, N'-diphenylisothiouronium (DDTU) in diisobutyl ketone and aqueous solutions containing varying molarities of hydrochloric acid. DDTU is a satisfactory reagent for the extraction of noble metals as a group from most of the associated base metals. Base metals such as iron(III), tin(II), and selenium(IV), which are co-extracted, can be removed from the organic phase by washing with 0.1 M hydrochloric acid; this affects only the recovery of iridium. Although the noble metals cannot be recovered from the organic phase by back-extraction, direct measurement in the organic phase is possible in ths presence of zinc dibenzyldithiocarbamate added as a releasing agent. The final solution for analysis contains 6 mg of additive per 10 ml of solution.     

Equilibrium and kinetics of Zn(II) bromide extraction with Amberlite LA-2 and methyl isobutyl ketone

The rates of extraction of Zn(II) from hydrobromic acid solutions into benzene solutions of the liquid anion exchanger Amberlite LA-2 and those into methyl isobutyl ketone (MIBK) have been investigated. The distribution equilibria of this system have been also studied. Under the used experimental conditions the extracted species of Zn(II) have been proposed. The kinetic data indicated a first order reaction with respect to Zn(II) in both systems, nearly one with respect to HBr and from 0–0.38 for LA-2. In case of extraction of Zn(II) with methyl isobutyl ketone, MIBK, the reaction order with respect to MIBK was found to be 4 and with respect to HBr inverse first order. The rate constants of these extraction processes were determined and the rate determining steps were discussed in the light of the obtained results.     

Determination of zinc in blast furnace flue dusts

Two methods for the determination of zinc in blast-furnace flue dusts are described. One involves a solvent extraction step using methyl isobutyl ketone to separate the zinc from the bulk of the interfering elements, followed by a complexometric titration of the zinc with EDTA, using Eriochrome Black T as indicator. The other employs differential pulse polarography with a hydrochloric acid + pyridine supporting electrolyte. In this method, the interference of iron is prevented by reducing it with hydroxylamine hydrochloride; aluminium is complexed with potassium fluoride. Other elements, with the exception of cobalt, do not interfere. Excellent agreement between the two methods is obtained in the range 0.01–0.6% zinc.     

The extraction of ferric chloride with methyl isobutyl ketone and amyl acetate

Summary The extraction of iron as ferric chloride in 7 M hydrochloric acid by a mixture of (1+1) or (2+1) methyl isobutyl ketone and amyl acetate is quantitative for macro as well as for micro amounts of iron. The distribution ratio is very high ( 4000). With these mixtures no emulsification difficulties are encountered as they are with methyl isobutyl ketone alone. The behaviour of 44 elements in this extraction has been investigated.     

Extraction into methyl isobutyl ketone of metal complexes with ammonium pyrrolidine dithiocarbamate formed in strongly acidic media

It is shown that stable metal complexes with ammonium pyrrolidine dithiocarbamate (APDC) are formed in strongly acidic (0.5–6 M) solutions and can be extracted into methyl isobutyl ketone (MIBK), although APDC is normally used for extractions from solutions at pH 2–12. Percentage extraction curves are presented for 24 elements (Ag, As, Au, Bi, Cd, Co, Cu, Fe, Ga, Ge, Hg, In, It, Ni, Os, Pb, Pd, Pt, Rh, Ru, Sb, Sn, Tl and Zn) from solutions of hydrochloric or nitric acid with and without addition of APDC. Some elements (e.g., Fe, Ga, Ge, In and Au) show identical extractions as their chloro complexes in hydrochloric acid with or without APDC. Others (e.g., Ni, Cu, Pd, As, Ag, Sb, It, Hg and Bi) are strongly extracted (K_d ? 20), from 2 M hydrochloric or nitric acid in the presence of APDC. Palladium (K_d = 8000), Sb (K_d = 10 000), and Bi (K_d = 3500) are particularly easily extracted. The potential of the extraction system was tested by extraction and quantification of palladium from the CANMET standard ore PTC-1; the mean value found was 12.55 μg g^?1 (ppm) palladium with a relative standard deviation of 7.6% (n = 12) and a relative error of 1.2% from the recommended value of 12.70 μg g^?1.     

New spectrophotometric thiocyanate determination of iron in metals,alloys, acids and salts

A rapid, sensitive and fairly selective spectrophotometric thiocyanate method for the determination of traces of iron in metals, alloys, acids and salts is described. The iron is isolated from the bulk of the sample by solvent extraction with methyl isobutyl ketone from ₇N lithium chloride solution or ₇N hydrochloric acid. The iron (III) thiocyanate color is developed directly in the ketone extract and then measured spectrophotometrically.     

The extraction of lead iodide by methyl iso-propyl ketone

A method is proposed for the isolation of lead by solvent extraction. When solutions of lead ions are treated with excess potassium iodide and hydrochloric acid (5 %), lead iodide is extracted quantitatively by methyl iso-propyl ketone. Employing a preliminary extraction with methyl iso-propyl ketone after conditioning the aqueous solution with ammonium thiocyanate and hydrochloric acid, practically all interferences are eliminated (except Cd and Ru).     

Determination of gallium in an iron-aluminium matrix by solvent extraction and flame emission spectroscopy

Solvent extraction of gallium(III) into methyl isobutyl ketone from hydrochloric acid solutions containing titanium (III) sulphate provides a rapid method for separation of gallium from an iron/aluminium matrix and may be employed to eliminate the interference of these elements in the flame emission spectrometric determination of gallium.     

Liquid-liquid extraction of tungsten(VI) with mesityl oxide application to an alloy steel

A new and simple method has been developed for the rapid extraction of tungsten(VI) with mesityl oxide. Quantitative extraction occurs from solutions 1M in hydrochloric acid and 12M in lithium chloride (as the salting-out agent) with 75% mesityl oxide in isobutyl methyl ketone. Tungsten is finally determined photometrically as the thiocyanate complex in the aqueous phase. Tungsten-(VI) can be extracted and determined satisfactorily in the presence of several elements. The method is shown to be applicable to an alloy steel.     

Quantitative goldbestimmung in filmmaterialien mittels flammenloser atomabsorption

A graphite rod electrothermal atomizer has been used for the AAS determination of traces of gold in hydrochloric and in hydrobromic acid solutions, and also after extraction into HBr-saturated methyl isobutyl ketone. Photographic film samples were decomposed first by enzyme action then by nitric acid/peroxide oxidation, and the gold was extracted into MIBK. For 10-μl aliquots of solution the 3s limits of detection were 3 × 10^?10g for aqueous solutions, 7 × 10^?10g for MIBK, and 7 × 10^?9 g/cm² for film.     

Estimation of iron in fruit samples by substoichiometric extraction with malonic anilide

A radiochemical solvent extraction method for the determination of iron(III) employing the chelating extractant malonic anilide (MA), synthesized in our laboratory, has been described. Effects of different parameters on the extraction of iron(III) from 2M hydrochloric acid into a mixed organic solvent (methyl isobutyl ketone (TIBK) and diethyl ether) have been studied in detail. The method was applied for the estimation of iron content in several fruits using the principle of substoiciometric isotope dilution analysis.     

The determination of antimony in natural waters with particular reference to sea water

A procedure is described for the determination of antimony in natural waters at concentrations down to 0.1 μg/l or less. The element is concentrated by coprecipitation with hydrous manganese dioxide (produced by the reaction of permanganate with ethanol). It is separated from manganese, iron and interfering elements by extraction from 5 M sulphuric acid, 0.01 M with respect to iodide, using methyl isobutyl ketone. After back-extraction with 0.4 M hydrochloric acid, it is determined photometrically using rhodamine B. The overall chemical yield of the process is measured radiochemically and amounts to ca. 80%. Sea water samples from the Irish Sea were found to contain 0.13–0.40 μg Sb/l.     

Masking of iron with fluoride in the extractive atomic-absorption spectrometric determination of chromium in steel

Chromium in steel is determined by oxidation to dichromate, extraction into methyl isobutyl ketone from 1-3 M hydrochloric acid, and atomic-absorption measurements on the extract. The interference of iron in the atomic absorption is eliminated by using fluoride to keep the iron(III) in the aqueous phase in the extraction step.     

Improved tribenzylamine-silver bromide extraction/atomic-absorption spectrophotometric method for the determination of silver in ores, related materials and zinc process solutions

An improved tribenzylamine extraction/atomic-absorption method for the determination of silver in ores, related materials and zinc process solutions is described. The method, which involves the separation of silver by a single methyl isobutyl ketone extraction of the tribenzylamine-silver bromide ion-association complex from ~ 0.5-2M sulphuric acid-0.14M potassium bromide, is simpler and more rapid than a previous method based on a triple chloroform extraction of the complex. Silver is stripped with 12M hydrochloric acid containing 1% thiourea as a complexing agent. Thiourea is destroyed with nitric and perchloric acids and silver is ultimately determined by atomic-absorption spectrophotometry in an air-acetylene flame, at 328.1 nm, in a 10% v v hydrochloric acid-1% v v diethylenetriamine medium. Cadmium and bismuth are partly co-extracted but do not interfere. Results obtained by this method are compared with those obtained previously by the tribenzylamine/chloroform extraction method and with those obtained by a direct acid-decomposition/atomic-absorption method.     

Extraction of palladium and platinum with trioctylphosphine oxide (TOPO) in various solvents from hydrochloric and hydrobromic acid media

The extraction of palladium and platinum with trioctylphosphine oxide (TOPO) in cyclohexane, chloroform, methyl isobutyl ketone (MIBK) and 2,2′-dichlorodiethyl ether (DCDE) from hydrochloric and hydrobromic acids in dependence on the concentration of the acids and the extractant has been investigated. The obtained relation have been discussed and the possibilities of the separation of palladium, platinum, gold and their simultaneous extraction have been pointed out.     

Decomposition of Cu(PCD)(2) extracted into IBMK and DIBK phases from hydrochloric acid media

The decomposition of the bis(1-pyrrolidinedithiocarbamato) copper(II) complex [Cu(PCD)(2)] extracted into isobutyl methyl ketone (IBMK) and di-isobutyl ketone (DIBK) from hydrochloric acid solution (0.01-8M) has been studied with UV-visible and ESR spectrometry. The mixed-ligand complex CuCl(PCD) is formed as an intermediate and CuCl(2) or CuCl3(-)(3), are formed as final products, in the decomposition of Cu(PCD)(2). The concentration of free hydrochloric acid dissolved in the extract has also been determined, and the effect of the free acid on the decomposition has been studied. The decomposition reaction of Cu(PCD)(2) extracted from hydrochloric acid solution can be thought of as a ligand substitution by Cl(-), and occurs with both IBMK and DIBK extraction.