RADIUM AND ITS WORK

Evening Post, Volume CII, Issue 32, 6 August 1921, Page 7

RADIUM AND ITS WORK

SOME FACTS AND FIGURES .

ONLY FIVE OUNCES KNOWN,

The United States has become within the brief space of a few years tho world's producer of radium. Indeed, of an anticipated world production of 25 grammes of radium in 1921, practically v all will coma from this count-rj;, writes Mr. H. A. Mount, in tho Scientific American.

Twenty-five grammes of radium sounds quite little when compared with the world production of any other precious metal. But when it is reflected that there exists in the whole world only about"five ounces of oxtracted radium, the production of nearly an ounce a year is large. But what will become of this ounce of radium ?

This is a pertinent question, for recently it has been proposed that the use of radium be restricted by legislative action «to medicinal uses. The action is inspired, no doubt, by tho fear that so much radium will be used in tho production of luminous material for tho faces of watches and clocks and similal' uses that humanity will be deprived of the medicinal benefits that would otherwise come from the radium. Another fear is that the_ visible supply of tho ores which now furnish the-radium 1 of commerce will be exhausted and that the annual production will be greatly curtailed.

The second objection is most easily disposed of. " When at the outbreak of the World War the importation of radium from Europe was cut off and mines wore opened in Colorado and Utah, it was seriously proposed to limit the use of radium to •medicine when experts predicted that not "more than 100 grammes of radium could be taken from the carnotite deposits there. But more than that amount has already been taken out and the visible supply is greater than ever before. Now deposits are being constantly discovered, and within the past month prospectorb have announced additional deposits estimated to'contain 90 grammes of radium. There has been a great deal of speculation among mining engineers, commercial users of radium, Government authorities, and others as 'to whother the supply of radium would be continuous. The present fields in Colorado contain the only radium ores in the world which are being worked commercially. Before tho war America went to Europe for its radium. This was obtained from pitchblende, which came from tho lead and silver mines o.f St. Joachimstahl. in Bohemia,. -While pitchblende contains from 30 to 70 per cent, uranium oxide, from which the radium is extracted, it always occurs, in small pockets in widely separated localities, so that it is merely a byproduct of other mining operations and no steady supply can be assured. - It is natural that pitchblende should have been the first source of radium, as it was the power of a piece of, this material to affect a photographic plate that first led the French scientist, Becquerel, anrt later others, to believe thero was prcseni some substance capable of omitting powerful and penetrating rays. To Mnra. Ourie, a Polish scientist, and to her French husband, have gone the credit for ifeolating this substance.

Tho ore from which radium is now extracted is known aa carnotite, and occurs in relative abundance in - Colorado an<l Utah, whero it follows generally an enormous geological fault which vuns through this part of the country. Tho ore contains but from 1£ to 4 per cent, uranium oxide, but once located, can bo mined by ordinary shallow mining process.'

THE EXTRACTION PROCESS.

The largest deposits so far discovered are in Paradox Valley,' '"'olorado, rr»cac than fifty miles from tho nearest railroad, over a barren desert trail. It is a natural conclusioiftliat tha extraction plant would be located at the mines under such circumstances, but such is not tlie cose. Tho largest producer of radium carries tlie o;e clear across the continent and extracts tho radiumjn a plant at Orange-, New Jersey. The reason is that for every ton o£ ore extracted, tons of chemicals and coal arc required, and it is cheaper, to movo the ore to the,chemicals than to move the ehcinieitls to th-3 ore.

Tho extraction process consists simply of eliminating- the various substances in the ore until finally the radium alone is left. A ton of good ore contains approximately one-two-hundredths of a gramme, about a, twelfth of a grain. To obtain this tiny bit of material tho ore is first ground and then put. through scores of chemical elimination processes. It is mixed lrith other chemicals, allowed to settle in big vats, and passed through many strainers. The final processes are carried out in the laboratory under the utmost care. About -20 per cent, of .the radium isl, lost, but the remaining 80 per cent, ia finally delivered in little glass tubes in the form of a radium salt—such as radium bromide, radium sulphate, radium carbonate, or radium chloride. Radium in its irreducible "form is a metal, but as such^ it lacks stability, and is therefore produced commercially' as a salt. Indeed, tho pure metal has been produced only once or twice, and very few persons have ever seen it. It is described ,as a whitish metal having the appearancd of the metals calcium or potassium. In the reduction process considerable quantities of vanadium and uranium are recovered, and were it not for this fact radium would cost considerably more than £30,000 a gramme—its present price. / A famous expert on radium is authority for the statement that the law of supply and demand has very little to do with tho price of radium. The soiling price is sot by tho cost of extraction, and the price can only be reduced as improved methods are found. Refinements in the process are constantly being made, but there is no immediate hope of any groat reduction in price.

WHAT BADIUM DOES.

Radium emits three distinot rays: Alpha rays, which have been identified' as positivo static electricity, and which form about 90 per cent, of the total emanations; beta rays, which are negative statis electricity, forming about 9 per cent, of the emanations : and gamma rays, vibrations, which form the remaining 1 per cent, of tlie emanations. In spite of the fact that tho alpha rays oompose most of the emanations, they have very little penetrating power; indeed, a sheet of paper will stop them. > The beta rays are more powerful, but can be stopped by about one-third of an inch of lead, while the gamma rays penerate over an inch thick -before they are absorbed.

Ir. the treatment of cancer and in the removal of useless tissue, for which radium has been found chiefly valuable in medical science, only the gamma rays are used. Sheets of metal are placed between tho patient and the radium to shield him from the alpha'and beta rays, which ara likely to cause dangerous and painful burns. Thus the surgeon makes hsb of only about 1 per cent, of the tremendous energy given off by the radium. When used in luminous material, however, tho energy of the radium is 100 per cent, useful.

Although tho medical uses for radium were first to be discovered and investigated, and the stato of that art is, of course, much further advanced than th« application of radium to luminous material, it -would be difficult to say which of these uses is most valuable to mankind.