Download 39. Uranium and Its Professions In the twentieth century the ninety

39. Uranium and Its Professions
In the twentieth century the ninety-second element of the Periodic Table has become
just about the most famous element. For it was uranium that started up the first nuclear
reactor. It gave men the key to mastery of a fundamentally new type of energy.
And now uranium is produced in large quantities: the world's production is over 40,000
tons a year. So far this is quite sufficient to meet the demands of nuclear power
engineering.
But strange as it seems, not more than 5 per cent of the uranium produced is utilized
directly (according to purpose). The remaining 95 per cent are called waste uranium. It
cannot be used directly because it contains too little of the isotope uranium-235, the
principal nuclear fuel.
But does this mean that so much labour on the part of geologists, miners, and chemists
is spent in vain?
You needn't worry: uranium has other, "nonnuclear" professions, and quite a number of
them, too. Non-specialists just know very little about them, which is too bad.
Uranium has caught the interest of biologists. It has been found that No. 92 is
indispensible to normal plant growth. For example, it perceptibly increases the sugar
content in carrots and beets, as well as in some fruits. Uranium helps valuable soil
microorganisms to develop.
Animals also need uranium. In a very interesting experiment rats were fed small
amounts of uranium salts for a year. The content of the element in their organisms
remained practically unchanged, and no harmful consequences were observed, but the
animals almost doubled their weight. Researchers believe that uranium aids greatly in the
assimilation of phosphorus, nitrogen and potassium, the most important vital elements.
Uranium in medicine? This is one of the oldest practical applications of the element.
There have been attempts to use its salts for treating various diseases, such as diabetes,
skin diseases, and even tumours. Nor have they been entirely unsuccessful. "Uranium
therapy" is now again in the order of the day.
Uranium finds a curious use in metallurgy. Its alloy with iron (ferrouranium) is added
to steel to remove oxygen and nitrogen. Steels made with ferrouranium can operate at
very low temperatures. Uranium-nickel steels are very resistant even to the most
aggressive chemical reagents, such as "aqua regia" (a mixture of nitric and hydrochloric
acids).
Another very interesting and singular role of uranium and its compounds is that of
catalysts for many chemical reactions.
Ammonia synthesis from nitrogen and hydrogen is sometimes accomplished in the
presence of uranium carbide. Uranium oxide accelerates the oxidation of methane by
oxygen, the production of methyl and ethyl alcohols from carbon monoxide and
hydrogen, and the preparation of acetic acid. Not a few products of organic chemistry are
obtained with the aid of uranium catalysts.
The chemistry of uranium is very lavish. It may be hexa-, penta-, tetra-, or trivalent in
its compounds. Uranium compounds of different valence differ so greatly that its
chemistry is like a combined chemistry of four different elements.