Laboratory Methods for the Separation and Purification of Mineral Samples

Abstract

Laboratory methods for separating pure mineralogical components from mixtures—for chemical analysis or other investigations—include gravimetric, magnetic, chemical, flotation, and electrostatic methods, as well as handpicking. Gravimetric methods involve the use of heavy liquids, elutriators, and mechanical devices such as vibrating tables and panning basins. Magnetic methods include the use of hand magnets and more powerful and versatile electromagnetic apparatuses, such as the Frantz Isodynamic Separator. Chemical treatments eliminate undesirable components through leaching. Although flotation and electrostatic methods are comparatively little used in mineralogical laboratories, they hold significant potential. For final treatment, handpicking under a microscope is an operation almost always required to achieve the desired purity. The criteria for selecting mineral separation methods depend on the properties of the mineral to be separated compared to those of the other minerals in the mixture, as well as their relative quantities. To illustrate how these criteria are applied, examples are provided showing the procedural sequence followed for several typical mineral mixtures.

Abstract from:

Gómez-Caballero, J. A. (2005). Historia e índice comentado del Boletín del Instituto de Geología de la UNAM. Boletín de la Sociedad Geológica Mexicana: Volumen Conmemorativo del Centenario Aspectos históricos de la Geología Mexicana, 57I(2), 149-185. http://dx.doi.org/10.18268/BSGM2005v57n2a3