Atomic absorption methods for analysis of some elements in ores and concentrates

Abstract

Published methods for rock and ore analysis by atomic absorption are fairly extensive, but scattered. This publication is a compilation of some general and specific procedures for application of atomic absorption analysis to rocks and minerals. In this application, the difficulties and problems lie primarily in the dissolution of the sample. Once dissolution has been effected, the actual atomic absorption analysis is usually relatively simple and straightforward. This publication, while not a treatise of atomic absorption theory or technique, provides a collection of dissolution methods for analysis of rocks and minerals with major emphasis on ore and concentrate analysis. No attempt has been made to include all elements that can be analyzed by atomic absorption, but only those elements and/or situations for which atomic absorption is the method of choice in our laboratory.The methods described have been tested and are used by the analytical laboratory at the New Mexico Bureau of Mines & Mineral Resources. The procedures were tested using a double beam atomic absorption unit, the Perkin-Elmer Model 303, equipped with a corrosion-resistant nebulizer. The ranges of liquid standards, detection limits, precision, and occasionally, interferences, depend to some extent on the instrument and the source lamp used in the determinations. Each user will have to test the procedures and determine these parameters for his equipment. Fuel conditions, ranges of liquid standards, detection limits, and precision data in this publication serve only as guidelines. The fuel conditions should be considered as those at ignition, and should be adjusted to optimum on the operator's instrument, using a standard solution. The fuel conditions may also vary with the amount of fuel in the tank. Burner height should also be adjusted to optimum, unless otherwise stated.Many of these methods have been adapted from referenced papers. Some changes have been made in the methods and the referenced authors should not be held responsible for any inaccuracies which may have been introduced. References are listed twice: at the end of each section, as well as in the general list at the rear of book. Unnumbered references listed at the end of a method pertain to the general method.The author was privileged to have had informal training in methods of rock and mineral analysis under Dr. Dexter H. Reynolds, former Research Chemist for the Bureau, now retired. Thanks are also due to Dr. Jacques Renault and David Schwab for their critical reading and suggestions.