日本金属学会誌

J. Japan Inst. Metals, Vol. 39, No. 4 (1975),
pp. 368-373

Determination of Oxygen in Metallic Manganese and Pure Aluminium by the Vacuum Fusion Method

Morimasa Saito1 and Emiko Sudo1

1National Research Institute for Metals, Tokyo

Abstract:

The determination of oxygen in metallic manganese and high-purity aluminium has been made by the vacuum fusion method with a carbon chip-tin-nickel foil bath, the method being effective for the determination of oxygen in metals which involve violent evaporation and are difficult to react with carbon.
In manganese, samples polished chemically and wrapped with a nickel foil (Mn:Ni foil=1 ∼ 2:2) was dropped in the crucible at 900°C and then the temperature was raised to 1550°C at the rate of 100°C/min and gases were extracted for 2 min. The oxygen extraction rate by this method was higher than those by the cupper bath and nickel-tin bath methods. The recovery of oxygen by this method was 97 ∼ 100 (%) in the known amount of manganese oxide and the deviation coefficient was within 6.6 (%) for electrolytic manganese.
In aluminium, comparison of various bath methods indicated that the above-mentioned method and the iron-tin, copper and nickel-tin bath methods gave inaccurate results with incomplete extraction. By the addition of silicon to the carbon chip-tin-nickel foil bath, the oxygen extraction was increased and the results of determination were in good agreement with those by the fast neutron activation method. Samples electropolished and wrapped with a nickel foil was plunged in the crucible at 1400°C after the addition of 0.1 g of slicon and then the temperature was raised to 1800°C at the rate of 100°C/min and gases were extracted for 3 min.


(Received 1974/09/25)

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