Analysis of deep-sea ferromanganese nodules using flame atomic absorption and emission analysis

All the samples were air-dried, crushed, and ground to a fine particle size (<100 mesh). Flame analyses were carried out with a solution that was obtained by the digestion of a 0.5-g sample of nodules in a Teflon-lined vessel. The resulting solution was transferred to a 100-mL volumetric flask containing 70 mL of a 5% boric acid solution and diluted to the mark. Standard solutions of the elements were prepared in an identical manner with 5% boric acid solution. Atomic absorption and emission spectrophotometric analyses were carried out for 22 elements with a Varian Model 5 atomic absorption spectrophotometer. A nitrous oxide-acetylene flame was used for the determination of Al, Ba, Mo, Sr, V, Ti, and Si. Arsenic was determined with a tantalum boat and a hydrogen-nitrogen flame, and the remaining elements were determined with an ai-acetylene flame.