Fractional Separation of Hafnium and Zirconium by Means of Triethylphosphate

Willard, H. H.; Freund, Harry

doi:10.1021/i560151a011

Cited by 21 publications

(11 citation statements)

References 4 publications

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“…Elving and Van Atta ( §) recently published directions for the separation and determination of barium, strontium, and calcium using dimethyl sulfate. In the presence of normally occurring (37), gallium (30) tin (12), zirconium ( 12) Titanium ( 28) Thorium (20) Zirconium and hafnium (31)b Zirconium (34) Zirconium (34) Thorium and the rare earths (S3), lanthanum and cerium (13)b, lanthanum and praseodymium (13)a, calcium ( 16) Magnesium ( 14), zinc (2), calcium and magnesium (7) Calcium (32) Barium (8), calcium (8), strontium (8) Barium (10) Barium (12) Lanthanum and praseodymium (25)b Zirconium (17) Thorium (15) Thorium (12), zirconium (4) Barium (9,26) a Methods for elements in italics may be found in periodical literature. i> Fractionation procedures.…”

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Precipitation from Homogeneous Solution

Gordon¹

1952

Anal. Chem.

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VOLUME 2 4, NO. 3, MARCH 1952 459 end points which are close together. When conditions are such that the wings of the curve are actually straight lines, but the end point is very poor, the ordinary method is sometimes superior to the differential method. For slow reactions, the differential method may be inapplicable.A buret is described which can be used either in the normal manner or to deliver solution at a uniform and low rate of addition.

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Precipitation from Homogeneous Solution

Gordon¹

1952

Anal. Chem.

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“…The precipitate obtained in this way is crystalline and readily washed. The separation of these elements by this process is considerably better than any previously attained (15). Table III shows a comparison of the results obtained by Larsen, Fernelius, and Quill and by the hydrolysis of triethyl phosphate.…”

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Separation by Precipitation from Homogeneous Solution

Willard¹

1950

Anal. Chem.

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When a precipitating ion is added to a solution in which a substance is to be precipitated, the local concentration of the former at the point where the solutions mix often causes coprecipitation of other ions which may remain adsorbed when the solution subsequently becomes uniform. This error is avoided by adding a substance which does not contain the desired precipitating ion as such, so that no immediate precipitation results, and the solution is homogeneous. Heat is then applied and the proper ion is formed by hydrolysis in the solution.If neutralization of an acid solution is required, the hydrolysis of urea to form carbon dioxide and ammonia is a convenient process.If a weak base is thus precipitated in the presence of the proper anion, a dense basic salt is formed. With aluminum, succinate is best; with iron, formate. Errors due to adsorption are therefore greatly decreased and far more effective separations are accomplished. Data for such separations are presented. Oxalate ion is

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“…[86][87][88] It is extremely difficult to separate zirconium and hafnium owing to their nearly identical chemical properties. Techniques considered for separating zirconium and hafnium are the fractional crystallization process [89,90], fractional precipitation process [91,92], ion exchange process [93,94], adsorption process [95], solvent (liquid-liquid) extraction process [96,97], and chloride distillation (extractive distillation) process [98]. Of the above, the chloride distillation process and solvent extraction process are used today in industrial separation.…”

Section: Zirconium Metal Reduction Processmentioning

confidence: 99%