The separation of metals by means of the mercury cathode: chromium

Chirnside, R. C.; Dauncey, L. A.; Proffitt, P. M. C.

doi:10.1039/an9436800175

Cited by 11 publications

(9 citation statements)

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“…The acid most commonly used is undoubtedly sulfuric acid. Although concentrations of this acid up to 5 M have been used (121), it is generally agreed that the concentration should be as low as possible without permitting precipitation to occur (28,37,73,81,152). The inefficiency of the cells reported by early investigators may have been due to their use of too high a concentration of acid (112), although the recording of acid concentrations in terms of "drops" makes this point somewhat obscure.…”

Section: A Nature and Concentration Of The Acidmentioning

confidence: 99%

“…When attention was turned to the application of the mercury cathode in separations, reduction of the time element became a necessity, for it was usually desirous that much larger amounts of an element should be deposited than had heretofore been the case. This objective was achieved by the use of larger cells (135,166), changes of mercury ( 73), and higher current densities (28). Concentration of the electrolyte has been found to reduce the time necessary for satisfactory deposition (27,28,79,155), bearing in mind again that certain metals are deposited with more difficulty than are others (145,148).…”

Section: Time and Temperature Of Electrolysismentioning

confidence: 99%

“…This objective was achieved by the use of larger cells (135,166), changes of mercury ( 73), and higher current densities (28). Concentration of the electrolyte has been found to reduce the time necessary for satisfactory deposition (27,28,79,155), bearing in mind again that certain metals are deposited with more difficulty than are others (145,148). A study of the efficiency of removal of iron, copper, and nickel with time has been made by Ford (47), who found that iron is deposited more rapidly when the other metals are present.…”

Section: Time and Temperature Of Electrolysismentioning

confidence: 99%

“…Of particular interest in cell design was the trend towards compactness, in order to facilitate the washing and, in some cases, the weighing of the cathode. Spoon-shaped cathodes, which were suspended in the electrolyte, were developed for determination (114,163) and the English workers Chirnside, Dauncey, and Proffitt, in an effort to obtain a simple inexpensive cell, devised the first unitized apparatus for the separation of metals (27,28). An extremely compact and convenient cell has been constructed in the Shell Development Laboratory (73,119,131,171).…”

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The Mercury Cathode and its Applications.

Maxwell¹,

Graham²

1950

Chem. Rev.

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Section: A Nature and Concentration Of The Acidmentioning

confidence: 99%

Section: Time and Temperature Of Electrolysismentioning

confidence: 99%

Section: Time and Temperature Of Electrolysismentioning

confidence: 99%

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The Mercury Cathode and its Applications.

Maxwell¹,

Graham²

1950

Chem. Rev.

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“…Electrolysis in a mercury-cathode cell has subsequently been used widely to separate interfering elements before the determination of titanium by colorimetric or gravi~netric methods, e.g., in the determination of titanium in ores (18), in rocks and minerals (4), in ferro-titanium (19), in nickel-base alloys (13), in chromium steels (6), and in high-temperature (20) and other alloys (2,22). We have made careful wave-height measurements on polarograms given by both electrolyzed and nonelectrolyzed aliquot portions of a solution of titanium and the data (240 wave-height measurements by two readers) confirm the view that titanium is quantitatively retained in the electrolyte during electrolysis with a mercury cathode.…”

Section: Removal O F I N T E R F E R E N C E Smentioning

confidence: 99%

The Polarographic Determination of Titanium in Steels and Nickel-Base Alloys

Graham¹,

Hitchen²,

Maxwell³

1952

Can. J. Chem.

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Titanium in steels and nickel-base alloys can conveniently be determined polarographically after electrolysis of a solution of the alloy in a n~ercur)l-cathode cell. A well-formed wave, the height of which is directly proportional to the concentration of titanium in the solution, is recorded using a supporting electrolyte that is 1.0 111 in tartaric acid, 0.5 AT in sulphuric acid, and 1.2 n/f in ammonium sulphate.The method is one of good precision arid yields values in excellent agreement with those given by umpire methods for samples of basic ope~l-hearth steel, 18-11 chromium-nickel steel, Monel, Inconel "W", and Nimonic 75 and 80. INTRODUCTIONThe only earlier work on the polarographic determination of titanium in metallurgical products appears to be that of Zan'ko, Geller, and Nilcitin (25) who proposed a method for the determination of this element in cast irons and steels. They report the determination of titanium in an acid tartrate medium after treating a solution of the alloy with aluminum dust. We have not been able to remove the interference of iron (111) by the use of this reducing agent; furthermore, the introduction of an appreciable concentration of aluminum ion is undesirable (3).Recent work in this laboratory on the polarographic deternliilation of titanium in rocks and minerals (4) has shown that very good polarographic waves for titanium are obtained in a medium containing tartaric acid, sulphuric acid, and ammonium sulphate. Interfering ions are removed by prior electrolysis of the solution in a mercury-cathode cell. The application of such a method t o the determination of titanium in steels and nickel-base alloys is discussed in the present paper. REMOVAL O F I N T E R F E R E N C E SBecause the half-wave potential for copper (11) in an acid tartrate medium is less negative than that of titanium, there is a limit to the concentration of copper that can be present without the occurrence of interference in the polarographic determination of titanium. Iron (111) also constitutes an interference (23). Electrolysis in a mercury-cathode cell is a very convenient and efficient way of removing from solution iron, copper, and nickel-and a score of other elements (12)-all without the introduction of foreign salts, and often in less time than that required by other procedures. In such an electrolysis chromium is not easily removed quantitatively but the chromium remaining in solution causes no interference in the determination of titanium, even in alloys high (20%) in chromium. The chromium content of the solution being polarographed should be Manuscript received Febrzrary 25, 1952.

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