Uranium's Scientific History - Part 2

As early as 1904, with the increasing interest in cancer therapy, the demand for radium started to grow. Once more Joachimsthal was in the limelight, but this time radium was the star product while uranium remained an element with limited uses. The radium industry started in France under the aegis of the Curies, who refused to take out any patents, believing that to do so would be contrary to scientific ethics, especially because of the medical applications. They were not rewarded for their altruism, because international development of the new industry was characterized by extreme greed for profits and brutal competition.

By 1906 radium was, due to its extremely low concentration in the ore and the many chemical steps necessary for its extraction, by far the most precious substance in the world. Its price had reached 750000 golden francs per gram, about 10 million present day dollars. It was produced from Bohemian ore in two French factories, which enjoyed a short lived monopoly. In 1907 the Imperial Austrian government placed an embargo on the export of uranium ore and its by-products, and proceeded to build a radium factory in Joachimsthal next to the factory producing coloured uranium compounds.

The Austrians expected to create a monopoly of their own, but thanks to the existing small uranium mines in Cornwall and Portugal, as well as American ore from Colorado, the French were able to stay in the radium industry. However, the First World War disrupted the industry in both countries shortly after a new producer, the United States, entered the market in 1913. By then, a total of about 20grams of radium had been produced in France and Austria.

The US industry was thus able to take over the monopoly. It was based on exploitation of the large Colorado deposits of carnotite, a low grade uranium and vanadium ore easy to process for radium. The extraction took place in Pennsylvania in a refinery belonging to the Standard Chemical Company of Pittsburgh. It put on the market about 200 grams of radium and 600 tonnes of uranium in various compounds between 1913 and 1926. The price of radium decreased from US$160000 to US$120000 per gram. About half this radium went to hospitals and the rest was used in luminous paint for dials.

The American radium-uranium industry retained the monopoly for almost ten years before it reverted to Europe, this time to Belgium. In 1915 a prospector had discovered at Shinkolobwe in the Belgian Congo a deposit of pitchblende and other uranium minerals of a higher grade than had ever been found before anywhere in the world, and higher than any found since. The discovery was kept secret by the Belgian mining trust Union Minière du Haut Katanga which mined the rich resources of copper and cobalt in the region. After the First World War ended a factory was built at Olen near Antwerp, and the secrecy was lifted at the end of 1922 with the announcement of the production of the first gram of radium from the plant using the African pitchblende.

The Belgian production capacity for radium was as large as its cost was low, and this soon convinced the Standard Chemical Company to abandon the race, which it did in 1926. Union Minière then enjoyed a near monopoly in the production of radium and could dictate the price, which was lowered to US$70000 per gram. It refused, however, to reveal its annual production, and even by 1989 has not opened its archives, probably to try to hide the fact that the radium was produced at far lower cost.

This attitude is difficult to understand many decades after radium has ceased to be extracted from uranium ores, and has in turn become a waste product with its presence a source of complication in the disposal of waste from the uranium mining industry. It is now practically worthless, having been superseded for use in radiotherapy by artificial radioelements created in nuclear reactors, especially by cobalt-60, which costs about one US dollar for the radiation equivalent of one gram of radium.

As it became dominant in the radium market, Union Minière also became the largest producer of uranium compounds, on a scale much larger than the needs of the world market. It tried to find a use for uranium in hardening steel alloys, but without success.

The prolonged industrial secrecy of Union Minière regrettably prevents a precise evaluation of the exact amount of radium separated in the world during its half century of glory. However, the total is probably between one and one and a half kilograms. This is a small amount compared to the ten kilograms of unextracted radium contained in today's annual worldwide uranium production of 30000 tonnes.

During the 1920s and 1930s the Belgian rate of production was limited neither by the capacity of the Congolese mines nor by that of the Olen refinery, but only by the funds available to hospitals and the needs of the market for luminous paint. The Congo mine was closed in 1937, as by that time more than 2000 tonnes of ore containing 65 per cent U3O8 were stockpiled, enough for probably 20 years of world radium consumption.

This stockpile was transferred directly from the Congo to the United States at the end of 1940, and provided the initial supply of uranium for the American atomic bomb project. Meanwhile, about 1200 tonnes of uranium in various compounds stored at the Olen refinery was captured by the Germans after the invasion of Belgium in 1940, only to be recovered in Germany by US troops at the end of the war.

The Belgians had lost their monopoly when the Canadians entered the radium market in the mid 1930s, making use of the pitchblende deposit discovered in 1930 at the Great Bear Lake. Competition forced the Belgians to lower their price repeatedly. When the Canadians could no longer compete, Union Minière formed a cartel in 1938 with the Canadian producer, Eldorado Gold Mines, with 60 per cent of the market for the Belgians and 40 per cent for the Canadians. They were able to raise the price of radium to US$25000 per gram, after earlier threats to cut it to below US$10000. However, the cartel was short lived and ceased operating when Belgium was occupied in May 1940.

Far away from the competition of the major producers, uranium production at Joachimsthal had continued uninterrupted. The mines had changed their name and their ownership in 1919 following the creation of Czechoslovakia. As the State Mines of Jáchymov they operated at a loss, producing about ten tonnes of uranium colouring compounds and three grams of radium per year. The mine in Cornwall, which had an even smaller capacity, was closed in the early 1930s because it was almost exhausted. Small-scale production also continued in Portugal during this period.

It is interesting to note that, in the absence of portable radiation counters before the Second World War, prospecting for radium was in practice a search for geological occurrences of uranium. After the war the reverse was true, with uranium deposits being discovered thanks to the radiation emitted by the radium and other decay products they contained.

While the battle for the monopoly in the production of radium was taking place, the scientific study of natural radioactivity and the use of radiation from radium and polonium as a tool for the study of the nucleus of the atom was progressing. This would lead to the discovery of nuclear fission and the use of uranium for the production of recoverable energy. Meanwhile, as already mentioned, the radium industry would decline and fall.

The road to the discovery of fission had begun as early as 1903, when Pierre Curie had measured the energy which is spontaneously and continuously produced by radium. To explain this phenomenon he suggested either that radium captured and re-emitted energy from outer space, or that it was due to a continuous and profound modification of the radium atom. He concluded that if the latter hypothesis was valid, 'the energy involved in the transformation of the atom is considerable'.

Rutherford and Soddy later confirmed this conclusion, and Soddy became the first to popularize visions of the good or evil which could result from harnessing the forces present in the heart of matter. He contrasted rose-coloured visions of the creation of paradise on earth and the eradication of deserts and ice-caps, thanks to unlimited resources of cheap energy, with dark nightmares of the destruction of cities and civilization under a hail of radioactive bombs. Sometimes the one followed the other and a happy and united world emerged from the ruins of war, a scenario which inspired the science fiction writer HGWells in his novel The World Set Free, written in 1913.

In this novel, full of astonishing predictions, Wells is the first to speak of 'atomic bombs', which are used in a European conflict set in 1956 called 'The Last War', followed by a peace conference, set at Lake Maggiore in Italy, where a new world is organized in which humanity enjoys in everlasting peace the many benefits of atomic energy.

At the start of the book, a university professor gives the following explanation to his pupils.

'This little box contains about a pint of uranium oxide; that is to say about fourteen ounces of the element uranium. It is worth a pound. And in this bottle, ladies and gentlemen, in the atoms in this bottle there slumbers at least as much energy as we could get by burning a hundred and sixty tons of coal. If at a word, in one instant, I could suddenly release that energy here and now it would blow us and everything about us to fragments; if I could turn it into the machinery that lights this city, it could keep Edinburgh brightly lit for a week. But at present no man has an inkling of how this little lump of stuff can be made to hasten the release of its store.'

Furthermore, in this same novel Wells places the discovery of artificial radioactivity in 1933, an extraordinary prediction as it actually took place in January 1934, and was, as Wells suggested, a major step towards the making of the atomic bomb.

In this same year, 1933, Lord Rutherford, who had been the first to produce, in 1919, an artificial transmutation by colliding an alpha particle emitted by polonium with an atom of nitrogen, still dismissed the possibility of harnessing nuclear energy as 'moonshine'. It was, however, at about this time that two of the fundamental discoveries necessary to allow nuclear energy to become a reality were made.

In 1932, the surprising effects of bombarding beryllium with alpha particles from polonium led the British physicist James Chadwick to the discovery of the neutron. Two years later the action of the same alpha particles on aluminium opened the way to the discovery of artificial radioactivity by the French physicists Frederic Joliot and his wife Irène Curie, the daughter of Pierre and Marie Curie, who was born the year her mother embarked on her revolutionary work.

Following this, from March 1934 to January 1939, there was an extraordinary mixture of competition and collaboration between the European laboratories involved in the study of the atom in Rome, Berlin, Paris and Copenhagen. They were searching for the solution to a precise and limited problem, the complexity and the far-reaching consequences of which no-one had predicted.

The problem was the identification of the surprisingly large number of artificial radioactive elements formed during the bombardment of uranium by the neutron flux emitted by a radium-beryllium source. It was to be the last episode in the uranium-radium saga, and appropriately both the ancestor element and its descendant were experimentally involved.

This work was initiated in 1934 by Enrico Fermi and his team in Rome, and was taken over in 1935 by Otto Hahn, Lise Meitner and Fritz Strassmann in Berlin. The Berlin team were convinced that transuranic elements were being formed, and believed that they had identified them after three years of investigations.

However, their results were disproved by Irène Curie and Pavel Savitch in Paris, who, although they did not find the solution to the enigma, put Hahn and Strassmann on the right track and allowed them to produce chemical proof of fission during the last days of 1938. A few days later, the explanation of the physical process was produced in Sweden by Meitner, by then a refugee from the consequences of the Nazi racial laws, and her nephew Otto Frisch. Frisch then carried out experiments to provide physical proof of fission in Niels Bohr's laboratory in Copenhagen on 15 January 1939.

In all, eleven scientists of five different nationalities (Austrian, French, German, Italian and Yugoslav) were involved in the experiments. This does not include the German chemist Ida Noddack, who had suggested in September 1934 that elements in the middle of the periodic table were being formed as uranium broke up on the introduction of a neutron into its nucleus. However, nobody had taken her suggestion seriously at the time as it was contrary to all conventional thinking, and she did not even try to verify her theory.

During the same period, mass spectrography studies of uranium in the United States revealed its isotopic composition. The presence of uranium-235 was discovered by Arthur Dempster in 1935, and the exact proportion formed by this isotope, 0.7 per cent, was determined by Ernest Niehr in 1938.

The scene was set for humanity to pass into the atomic era, when uranium would become the major actor, while radium, having played its part, would fade from prominence.

Reference
1.Wells H G. The World Set Free. Collins, London and Glasgow, 1914.

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