CHAPTER XVIII

THE CHEMICAL TREATMENT OF MONAZITE

It has been stated in the previous chapter that the first Auer mantles were made of mixtures of various rare earth oxides, the mixture of thoria with 1 per cent. of ceria being first employed in October, 1891. The impetus given to the mantle industry by the success of the new mixture caused an immediate demand for thoria, which was at that time extracted from thorite (see p. 43). A ‘thorite-fever’ broke out along the coasts of Scandinavia, and the price of orangite rose to 600 marks per kilogram (about £13 10_s._ per pound avoirdupois), sinking again shortly to 80 marks[497] (about £1 16_s._ per lb). The discovery of the monazite sands of the Carolinas and Brazil, which at the present rate of consumption may be considered to be, for all practical purposes, inexhaustible, placed the industry on a firm basis, and the pure monazite, extracted from these deposits by the methods outlined in