New radium ore fields were discovered in Czecho-Slovakia in 1922. The production of radium in that country increased from .7746 gram in 1911, to 1.7118 grams in 1915, and 2.2310 grams in 1920. In 1922, steps were taken to modernize the plants in the Jachcymov district (Bohemia), where the known supply will last 20 years at the present rate of production—a little more than two grams a year.
The famous Joachimstahl pitchblende deposits were a monopoly of the Austrian Government before the World War, but they are now being worked by the Imperial and Foreign Corporation of London, under an agreement with the Czecho-Slovak Government. In 1922 a loan of two grams of radium (valued at more than $300,000) was made to Oxford University, for a period of fifteen years. This material is being used for experimental purposes by Prof. Frederick Soddy, of Oxford, and his associates. It has been stated that one of the chief objectives is the discovery of a method for the release and control of intra-atomic energy.
Pitchblende has been found in only a few places—in Bohemia (Czecho-Slovakia), southern Saxony, Cornwall, and Gilpin County, Colorado. So far, this ore has not been the source of any radium produced in this country.
When the original radium minerals (uraninite, samarskite, brannerite, etc.) break down through weathering, other radium minerals are formed from them, such as autunite, trobernite, carnotite, and tyuyamunite. The two latter ores are the most widespread and abundant. Autunite, a phosphate of calcium and uranium, is as active as uranium. Carnotite and tyuyamunite cannot be distinguished visually from each other. Both are a bright canary-yellow in color, and are powdery, finely crystalline, or, rarely, clay-like in texture. Both these minerals are found in the same section of Utah and of Colorado, usually associated with fossil wood and other vegetation, in friable, porous, fine-grained sandstone.
The only other deposits that yield tyuyamunite in marked quantity are those of Tyua-Muyun, in the Andiyan district, Ferghana Government, central Asiatic Russia (Russian Turkestan), where it occurs with rich copper ores in a pipe in limestone.
The radium salts—hydrous sulphate, chloride, or bromide—are all white or nearly white substances, no more remarkable in appearance than common salt. Neither radium nor the radium minerals are in themselves luminescent. Tubes containing radium salts glow because they include impurities which the invisible radiations from the radium cause to give light. The pure radium metal has been isolated only two or three times, and few persons have seen it.
NEW SOURCES OF RADIUM
In 1921, a rich deposit of pitchblende was discovered in the province of Ontario, Canada. Since 1921 there has been a rather considerable exportation of radioactive minerals from Madagascar; and in 1922 deposits of uranium oxide (U3O8) were discovered in Switzerland. During the same year an unknown Belgian traveler sold to a curio dealer a strange stone picked up in the Congo. The dealer sold it to the British Museum. Upon examination the stone was found to be radioactive. Belgian geologists were immediately informed, and a Belgian mission was sent to the Katanga district, where the stone was found. Two veins of chalcolite (torbernite) containing substances rich in radium were soon located by the geologists, one near the Portuguese frontier. Chalcolite, the crystallized phosphate of copper and uranium, is twice as active as uranium.
The newly discovered mineral has been given the name “curite,” in honor of Mme. Curie, the discoverer of radium. These deposits are now known to be the richest in the world. And, what is hardly less important, the radium may be isolated by simple dissolution in nitric acid, even in the cold. It is also readily dissolved in warm hydrochloric acid. Only 15 tons of the ore need to be treated to produce a gram of radium.
Curite is found in three forms, as translucent reddish brown needle-like crystals; as compact saccharoid crystalline aggregates, orange in color; and as orange-colored earthy masses surrounding the preceding variety. The chemical composition is expressed by the formula 2(PbO)5(UO3)4(H2O).