RAREST METAL

Evening Post, Issue 99, 24 October 1934, Page 7

RAREST METAL

PROTACTINIUM

ISOLATION ACHIEVED

(From "The Post's" Representative.) NEW YOEK, September 26. Element 91, or protactinium, a power« ful radio-active substance, rarer than radium, and, next to uranium, the heaviest of the 92 elements, has been isolated for the first time by science in. its pure, metallic state by Dr. Aristi<s yon Grosse at the resoarch laboratories of the Universal Oil Products Company, of Chicago. The achievement is described as even more difficult than the isolation of radium by Madame Curie in 1910, for which she received the Nobel Prize for the second time. Madame Curie worked unsuccessfully ia tho last two years of her life to isolate protactinium. So rare is protactinium that it exists only in the ratio of one part in. 10 000,000 in pitchblende, the ore in which radium is found. It disintegrates naturally into the element actinium, which is 140 times more active than radium, and has never yet been seen, by man. Both protactinium and actinium promise to be as useful as Tadium in the treatment of cancer. _ Protactinium has the same emanations and Tadiations as radium, namely, alpha particles, beta rays, and gamma rays. Actinium also gives off radio-active emanations. Out of one ton of pitchblende residue of radium ore, which had been lying on the dump heap at Joachimsthal, Czechoslovakia, for moro than thirty years, and considered worthless waste. Dr. yon Grosse extracted one-tenth of a gramme of pure protactinium. Two more tons of the "waste" are now ready for extraction. In collaboration with Sir Francis William Aston, of Cambridge University, the genealogy of protactinium and of radium has been worked out. When the news of tho discoverywas made known, the owners of the pitchblende claims at Great Boar Lake, in North-west Canada, announced that Madame Curie had been supplied with several tons of their product, in tha hope that she might isolate protactinium. Tests were still being conducted at -the radium refinery at Port Hope, Ontario. .