OTHER TITLES IN THE SERIES ON ANALYTICAL CHEMISTRY Vol. 1. WEISZ—Microanalysis by the Ring Oven Technique Vol. 2. CROUTHAMEL (Ed).—Applied Gamma-ray Spectrometry Vol. 3. VICKERY—The Analytical Chemistry of the Rare Earths Vol. 4. HEADRIDGE—Photometric Titrations Vol. 5. BUSEV—The Analytical Chemistry of Indium Vol. 6. ELWELL AND GIDLEY—Atomic Absorption Spectrophotometry Vol. 7. ERDEY—Gravimetric Analysis, Part 1 Vol. 8. CRITCHFIELD—Organic Functional Group Analysis Vol. 9. MOSES—Analytical Chemistry of the Actiniae Elements THE ANALYTICAL CHEMISTRY OF THORIUM by D. I. RYABCHIKOV and Ε. K. GOL'BRAIKH Translated by A. D. NORRIS LECTURER IN PHYSICAL CHEMISTRY THE UNIVERSITY OF HULL Translation edited by R. BELCHER and L. GORDON P E R G A M ON PRESS OXFORD · LONDON · NEW YORK · PARIS 1963 PERGAMON PRESS LTD. Headington Hill Hall, Oxford 4 and 5 Fitzroy Square, London, W. 1 PERGAMON PRESS INC. 122 East 55th Street, New York, 22, Ν. Y. GAUTHIER-VILLARS ED. 55 Quai des Grands-Aug us tins, Paris, 6e PERGAMON PRESS G.m.b.H. Kaiserstrasse 15, Frankfurt am Main Distributed in the Western Hemisphere by THE MACMILLAN COMPANY * NEW YORK pursuant to a special arrangement with Pergamon Press Limited Copyright © 1963 Pergamon Press Ltd. Library of Congress Catalogue Card Number 63-10065 This translation has been made from the Russian ANALITICHESKA Y A KHIMIYA TORI Y A Published in Moscow, 1960, by IzdateVstvo Akademii Nauk, SSSR Set in Monotype Times New Roman 10 on 12 pt. and printed in Great Britian by J. W. ARROWSMITH LTD., BRISTOL GENERAL INTRODUCTION TO THE SERIES THE V. I. Vernadskii Institute of Geochemistry and Analytical Chemistry of the Academy of Sciences of U.S.S.R. has embarked on the publication of a series of monographs on the analytical chemistry of various elements. The series will include about 50 volumes in all, and will be issued over a period of about 5 years. The need for such a series has been felt for a long time, and now that a large amount of experimental material has been accumulated in many laboratories it has become both possible and necessary to proceed. The projected series will be the first of its kind. The analytical chemistry of any element and its compounds is in these days a complex subject with many aspects, both because of the complicated nature of the results required and the wide concentration range which must be reckoned with, and because of the variety of available methods. A general plan has been laid down for the monographs, both as to contents and as to arrange- ment of material. Each monograph will contain general information on the proper- ties of the chosen element and its compounds. A description will then be given of those chemical reactions which are of importance for analytical purposes, followed by an account of physical, physico-chemical and chemical methods which may be used in the quantitative determination of the element—commencing with the analysis of the ores, and continuing with end products such as metals, alloys, oxides, salts and other compounds and materials. As a general rule the principles of the method of determination are first given, and are then followed when necessary by a detailed description of the whole process. Rapid methods of analysis are noted where necessary, and a separate place is given to the methods of determination of the so-called impurity elements in pure mat- erials. Attention is given to the precision and sensitiveness of methods, in accordance with the general tendency towards increased sensi- tiveness in methods used to determine trace quantities of impurity elements. The monographs will contain a comprehensive list of references ix χ GENERAL INTRODUCTION TO THE SERIES to recent literature, which should be especially useful to a wide circle of chemists, and especially analytical chemists in research institutes and factory laboratories and in various other aspects of public life, as well as for teachers of chemistry and students in higher academic establishments. The preparation of the monographs has been placed in the hands of the most eminent specialists in the particular fields of analytical chemistry concerned. The separate volumes will be issued inde- pendently as they are ready. The monograph on thorium is at present prepared, and those on the analytical chemistry of pluto- nium, lithium and gallium, amongst others, are under preparation for the press. We should welcome suggestions and opinions from readers of the monographs. The Editorial Board. FOREWORD THE use of thorium as a raw material for the manufacture of nuclear fuel, as well as in other recently developed technical fields, has stimulated a comprehensive study of the element. A large number of works have been published in recent years, giving detailed infor- mation on the properties of the metal and its compounds, especially those used in the isolation and determination of the element in natural and industrial materials. The literature, especially that published abroad, contains reviews of the chemistry and analy- tical chemistry of thorium by C. J. Rodden and J. C. Warf [1710], G. Moeller, D. Schweitzer and D. Starr [1503], G. T. Seaborg [1816-20] and J. Katz [1180], and others. Unfortunately, however, these reviews are far from comprehensive, and leave untouched many investigations reported in various journals. Because of this we have attempted here to give a systematic treatment of the available factual material. The more than 2000 references to work used in the preparation of this volume com- prise the great majority of those published in the last decade, but it is impossible even for such a survey to keep pace with the new publications, which appear constantly in a science which is develop- ing so rapidly. In addition to the strictly analytical section of this book, a chapter is provided on the physico-chemical characteristics of the element. The four following chapters describe the chemical and physico- chemical methods of determining thorium, its removal from ele- ments occurring with it, and its determination in various natural and industrial materials, as well as the determination of impurities in the metal. References to literature not actually used in the book, but likely to be of interest to analytical chemists and specialists in other fields of science, are given in the text in smaller print. We have arranged the material in relation to the importance of the various reagents, and have adhered to the commonly accepted classification of organic substances. The authors wish to express their gratitude to their colleagues in the Institute who have helped with advice during the preparation of the manuscript for the press, and would particularly express xi xii FOREWORD their appreciation to Correspondent-Member of the Academy of Sciences of U.S.S.R. I. P. Alimarin, to Doctors of Chemical Science P. N. Palei and V. I. Kuznetsov, to Candidates of Chemi- cal Science A. A. Nemodruk and A. N. Ermakov, as well as to Candidate of Chemical Science V. K. Belyayev and Scientific Assistant M. P. Volynets for their help in the literature survey. D. I. RYABCHIKOV Ε. K. GOL'BRAIKH PREFACE THE writer notes with interest that the Academy of Sciences of the U.S.S.R. is sponsoring the publication of some fifty volumes on the analytical chemistry of the elements. These volumes should prove of great value to those working in this field, particularly as they will undoubtedly cover recent U.S.S.R. work. The present inaugural volume on the Analytical Chemistry of Thorium must be regarded as one of the most important of the series, dealing as it does with an important atomic energy material. Its translation under the aegis of the Pergamon Institute will be greatly welcomed. It is noted that the volume on plutonium will be one of the next to follow. The references given in the Russian text appear to cover the subject up to the end of 1955, with a few 1959 entries. The present writer has supplied further references (with titles of papers) to the end of 1961, with some 1962 entries. It is thought that this supplementary bibliography should add to the value of the book. No attempt has been made to classify the supplementary references, as this would lead to much overlapping. The entries are alphabetical by first- named Author, and their serial numbers are followed by the letter "S". A.E.R.E. Harwell R. W. CLARKE xiii CHAPTER I OCCURRENCE OF THORIUM AND ITS MOST IMPORTANT PROPERTIES ORES AND DISTRIBUTION OE THORIUM Thorium was discovered by Berzelius in 1828 during his investi- gations of a mineral later called thorite, obtained from the island of Loveoya, near Brevik in Norway [371, 820]. It was given its name in honour of Thor, a god in Scandinavian mythology, as early as 1817, when Berzelius formed the erroneous view that the phosphate of a rare earth element of the yttrium subgroup, occurring in a mineral obtained from Finnbo, belonged to a new, at that time unknown, element [369, 370]. For the history of the discovery of thorium see also [364, 1555]. The element is widely distributed in the earth's crust [22, 42, 105, 198, 220, 1564], of which, according to Vinogradov [47] it con- stitutes 8 χ 10~4 per cent. It is, however, only rarely encountered in appreciable concentrations. The thorium content of basic rocks is considerably smaller than that of acidic rocks [42, 1629, 1698]. Thus, its proportion by weight is 1-2 χ 10-3 in granites, compared with 5xl0-4 in dunites [47, 198]. The thorium content of the hydrosphere varies between 10~5 and 10~9 g/1. [144, 178, 1153, 1609, 1610, 1835, 2047-8]. Its weight proportion in iron meteorites varies from 0-9 χ 10-6 to 4-3 χ 10-8 per cent, while that in stone meteorites is 2-4 χ 10~5 per cent [189]. Thorium minerals are most often encountered in igneous rocks, pegmatites, veins and alluvia, of which the last are the most important industrial sources. Almost all thorium minerals are resistant to natural attack, so that there is little tendency for the concentration of the metal in secondary minerals as a result of such attack. The most important thorium minerals are monazite, thorite, and thorianite. Although monazite contains only from 1-4-28 1 2 THE ANALYTICAL CHEMISTRY OF THORIUM per cent of thorium [177], the monazite deposits are the most important primary sources of the metal. Thorium is a major com- ponent of thorite and thorianite. but these minerals are quite rare and have no practical importance. Recent evidence [1560, 1856, 2036] discloses the discovery of vein deposits containing thorium in the White Mountains, near Powderhorn in Colorado, as well as in California [1560], New Mexico, Montana, Wyoming and Idaho [1981]. Deposits of industrial importance [4, 139, 303, 1021, 1384, 1921, 2027] occur in Brazil, India, Ceylon, Tasmania, Nigeria, and the Scandinavian peninsula. In the U.S.A., in addition to the locations mentioned above, deposits occur in Colorado, North Carolina and Virginia and other states. A large part of the world production is obtained from Brazil, India, Ceylon and U.S.A. [925, 1193, 1336, 1513, 2028]. Reserves of monazite in India are estimated to exceed 2,000,000 tons. Indian monazite from the Malabar coast and Travancore contains from 8 to 10 per cent of thoria, TI1O2, while Brazilian monazite from the Baia coasts and Santo Esperito contains on the average ca. 6 per cent [1744]. Monazite is obtained in U.S.A. from the sand dunes near Jacksonville in Florida, and from California, Colorado, Oregon and Washington [1981], as well as from the auriferous sands of Central Idaho. Concentrations of monazite with around 7-5 per cent thoria occur in isolated places in the iron-mining region of Marquette in northern Michigan [2018]. Monazite sands are also encountered in large quantities along the sea shores, in river beds and in coastal banks in western Taiwan. The thoria content of the last named varies from 4-2 to 6-8 per cent [2142]. Information presented at the First Geneva Conference on the Peaceful Uses of Atomic Energy reveals that new sources of thorium have been found in South Korea [2142], Sweden [1919], Norway [1848], Jugoslavia [1702], Greece, Thailand and Aust- ralia [1642]. The nominal price per metric ton of monazite concentrates has changed thus with time: $120-180 in 1922-29; $50-75 in 1929-46; $100-150 in 1947; and $140-200 in 1948. Since 1949 the price price has further increased to $245[1744].