OCR Text |
Show CADMIUM IS ONE OHM METALS Chief Source of Product Is Zinc Ores, Though Sometimes Found in Lead. The chief source of cadmium is zinc ore, though small quantities of this comparatively com-paratively rare molal aro contained In some lead ores. The world's cadmium output Is derived largely from Sllcsla, but within tho last two years the motnl has been produced In tho United States, and the valuo of the nnnunl Imports of i-admlum has dropped during that time from $10,500 to $L'300. The zinc ore of the Joplln district contains as high a percentage per-centage of the metal as tho cadmium-bearing cadmium-bearing zinc ores of Silesia. Some Uses of Cadmium. Cadmium melts at a low temperature and. like bismuth, lowers tho melting point of alloys In which It Is used. Bismuth, Bis-muth, however, forms brittle alloys, but manv alloys of cadmium are ductile and malenble. yet hard. Tho melting points of theso alloys aro lower than the melting melt-ing points of any of the metals composing compos-ing them. Several of them liquefy at temperatures considerably below that of boiling water, and a silvery-looking "trick'' teaspoon mndo of one of these compounds melts In a cup of tea to tho great astonishment of the ton-drinker. An alloy of cadmium is used In making automatic tire extinguishers, In which water under pressure Is released In a jot or spray by the melting of cadmium under the heat of tho fire. The brilliant yellow pigment known as cadmium yellow Is cadmium sulphide, which forms one of the most permanent colors obtalnablo for artists. This pigment pig-ment Is used also by some railway and streetcar companies as a protective covering cov-ering for other loss pormancnt yellows that are employed In painting their cars and coaches. Yellow paints that arc darkened by the sulphide gases In coal smoke or that fade tinder tho action of sunlight are In this way kept brilliant by a semi-transparent coat of cadmium yellow. yel-low. Various salts of cadmium are used in the arts, In medicine, dentistry, electroplating electro-plating and in the chemical laboratory. Boport Ijy the Geological Survoy. A report on cadmium in 190S, prepared by C. E. Sicbenthal, has just been published pub-lished by the United Slates Geological Survey ns an advance chapter of "Mineral resources of the United States, calendar vear 1908," and can be obtained by ap-'plying ap-'plying to the director of the survey at Washington. The report contains tables showing production pro-duction and Imports, a statement of the available resources, analyses of cadmium-bearing cadmium-bearing zinc blendes, and sections on the metallurgy and uses of cadmium, including includ-ing a table of alloys. |