Atomic absorption spectrophotometric determination of selected elements in ferromanganese nodules from the Pacific, Atlantic, and Indian Oceans

Twenty-one samples of deep-sea ferromanganese nodules collected from the Pacific, Atlantic, and Indian oceans were supplied by the Lamont-Doherty Geological Observatory of Columbia University and the Hawaii Institute of Geophysics, University of Hawaii. The air-dried manganese nodules were crushed with the aid of a ceramic mortar and pestle, and sorted according to particle size using a set of U.S. standard mesh sieves. Powdered nodules (100/150 ?m) in particle diameter) were dried overnight at 450°C in a Lindberg furnace, and the weight loss of the sample was measured for H2O concentration determination. Exactly 500 mg of the dehydrated samples were acid-digested in a pressurized Teflon