PfLK/NGTON AND IYYLIE-RARE EARTH COMPOUNDS. I 3%
PRODUCTION OF RARE EARTH AND ZITE. PART I THORlUM COMPOUNDS FROM MONA-By E. S. PILKINCTON and A. \'. \'YLIE A process is described for the separation of rare earth clcments in monazite into the following products : (a) cerium group hydroxides containing thorium hydroxide, (b) crude thorium osalate. Quantitative aspects of the various methods used to accomplish the separations have been investigated. The process is suitable for large scale operation.
Of the numerous methods of processing monazite reported in the literature,' few are described in detail and thc emphasis in many of these procedures is chiefly placed on recovery of thorium. For many years thorium was regarded as the most valuable component of the mineral and although it has been stated that monazite is now valued chiefly for its rare earth content,? future industrial developments may well create a renewed demand for thorium compounds. Our investigations of rare earth compounds were undertaken with the object of developing simple and inexpensive methods of preparation which could be applied in large scale operations, and at the same time of recovering maximum yields of thorium. During the investigation the authors became aware of a process3 embodying several features similar to those described below. Our procedure, however, is sufficiently different in detail to warrant description. Moreover, the quantitative aspect of the various operations has been investigated, and these have previously been described only incompletely in the literature.
Numerous products of value to the metallurgical, glass, optical instruments, chemical, thermionic-valve, and other industries are obtained from monazitexn. Ib, IG % and the growth of these industries in Australia has stimulated a demand for such products. The mineral is found in smdl amount in many localities in the Commonwealth, such as Western Australia, South Australia, and Tasmania, but the most accessible deposits are found in the beach sands of northern New South Wales and southern Queensland.G Monazite is produced from the sands as a by-product of mining operations designed to recover the more abundant minerals such as zircon, rutile, and ilmenite.5. For experimental purposes monazite from this source was obtained in the form of concentrates containing 75-85% of the pure minerd. Since the main impurities are only slightIy soluble in sulphuric acid, this product may be used in preparative work without further treatment. T o obtain the pure mineral, rutile, ilmenite, chromite, cassiterite, zircon, and other minerals were removed by repeated fractionation of the product on a high intensity magnetic separator. Of the final product 9804% was soluble in sulphuric acid and may be presumed to be monazite. The screen analysis was as follows : TyIerscrecn .. +roo XW-ISO XSO-ZOO -200 Weight, y:, . . 0 . 7 83 1 5 6 0.7 Chemical analysis was carried out by dissolving the product in concentrated sulphuric acid, Ntering off insoluble matter and determining the composition of the filtrate. Typical results for a pure sample of New South Wales monazite are given below. There appears to be little variation in the composition of the mineral with the locality of the beach sands.? U/ ,o 7 -2 0 27-10 o vgr (yttrium-and terb~um-group oxides) 2 8 . 2 0 0.64 Tho, Ce,O, M.0, 32.9 (other cerium-group oxides) Y.,b, Fos : g 0'10 0 ' 2 2 Fe;O.+TiO, 0.75 Igrution loss 0'10 (IOOoq siqp 0.15 (soluble) Insoluble in H,SO, I -60 * Inform. Circ. 7233, 1943, United States Bur. Mines; Minernls Year Book, United States Bur. Mines (Annually); "The Mineral Industry " by Roush (N.Y.) (Annually) ; Also Refs. r(a), x(b), I(C)