Uranium geochemistry, mineralogy, geology, exploration and resources / Геохимия, минералогия, геология, разведка и ресурсы урана

The uranium minerals that today are at the centre of worldwide attention were unknown until 1780, when Wagsfort found a pitchblende sample in 10hanngeorgenstadt. This discovery passed unnoticed, however, since Wags fort thought that it contained a black species of a zinc mineral-hence the n':lme 'pitchblende' (= pitch-like blende). Seven years later, Klaproth, while examining the mineral, noted that it contained an oxide of an unknown metal, which he called 'uranium' in honour of the planet Uranus, recently discovered by Herschel. Klaproth also believed that he had separated the metal, but, in fact, the attempt failed, and uranium, given its strong affinity with oxygen, was not separated until several years later. In 1833 Arfwedson attempted the separation and, in so doing, reduced the pitchblende. His attempt was not successful and only U02 was obtained. It was Peligot, in 1840, who was finally successful. He managed the reduction of the metal working with metallic potassium. It should be remembered that twelve years earlier Berzelius had isolated thorium.

This successful outcome of the experiment, however, was not given much importance in uranium history because, initially, there was little interest among scientists in this metal and in the industrial-technical field the many attempts to use it in the form of metal had scarcely proved successful. Attempts were made to use it for making Auer mantles in gas-lighting; filaments in electric light-bulbs were also tried, but both experiments failed. Only U 30g, some uranates and some uranium salts were utilized as dyes in ceramics and in the glass industry, and also for special photographic preparations. As a result of such a limited utilization, the demand for uranium remained so low that, at the end of the last century, the only mineral deposit to be exploited was that in 10achimsthal, Bohemia-the same formation in which, in 1780, Wagsfort had found the first pitchblende sample. The other known mineral deposits at that time-those in Portugal, Cornwall, Colorado, etc.-were practically untouched. Even thorium found no practical application until 1885, when Auer used the oxide for constructing the mantles that had been patented by him.

The year 1895 marks the beginning of a new chapter in the history of uranium minerals. Becquerel discovered the radioactive property of pitchblende and the Curies isolated radium. Suddenly scientists everywhere became interested in uranium minerals, which assumed a new importance in the mining industry. The extraction of radium from uranium salts led to the development of significant mining exploitation at St. Ivesin Cornwall, in the Paradox Valley in Colorado and in Portugal.  The first discoveries of uranium minerals in Katanga go back to 1915 and in 1921 exploitation was begun. The wealth of these mines was such as to put into difficulty all the others, including the loachimsthal deposits.

Since then the uranium market has been subject to two other turning points that, in the course of a few years, have made this metal an essential raw material. First, the destructive property of fission reactions made uranium a metal of fundamental strategic importance, increasing research in some nations, but the revolution came with the plan for the real possibility of utilizing chainreactions for energy production in place of conventional fuels. Since that time a 'uranium race' has been in progress in many countries-often justified by the well-founded hope of becoming self-sufficient with regard to energy, or at least of paying off a part of the financial deficit due to increasing fuel imports.

The importance of electro-nuclear energy should, however, be considered on the world rather than the national scale, especially when the following points are taken into account: the very marked increase in the demand for energy, the increasing cost of classic fuels and the need to use the latter more and more for specialized purposes (chemical, iron and steel industries, motor-vehicle traction, etc.). Thus, exploiting radioactive material is a very urgent national and world problem and the many aspects of the geochemistry and geology of uranium and thorium ore deposits are of extreme value in both theoretical and practical terms. With these points in mind, in 1960 one of the editors (F.L) presented Lezioni di Geologia dell'Uranio (lessons on the geology of uranium), which summarized a course held for a decade at the School of specialization in applied nuclear physics at Milan Polytechnic. Owing to the novelty of the subject and the particular interest that it holds for the development of the nuclear industry, these lessons quickly became obsolete, and it was felt that a new publication was necessary for both students and practising exploration geologists. Because of the complexity of the subject, which, if it is to be treated thoroughly, should be considered as an interdisciplinary field of research, with the help of our co-editors we decided to promote this volume in which. various specialists treat the problems that are presented by the geology of uranium in the widest sense. We hope that the presentation of these complex problems-from the mineralogy of uranium to the ~earch for it and its practical utilization-from different aspects and as completely as possible has been successful. We wish to thank all our collaborators and the Institution of Mining and Metallurgy, which has assumed responsibility for publishing this volume. <...>