Influence of carbon dioxide in the determination of oxygen in copper by reduction fusion.
It has been reported that copper melted in a graphite crucible at high temperature will give off its oxygen content mainly as CO and partially as CO(2). Thus if oxygen in copper is determined by means of apparatus designed to measure only CO as the reaction product, the results are obviously liable to error. Methods of suppressing formation of CO(2) during the fusion process are proposed. When the oxygen is determined by gas chromatography, formation of CO(2) can be suppressed by adding a 0.5% Si-1.5% NiCu bath-alloy together with the copper sample or by inserting a spectrographically pure carbon rod into the graphite crucible used for the fusion. When the oxygen is determined by coulometry, formation of CO(2) can be suppressed by the addition of the SiNiCu bath-alloy or by appropriate modification of the graphite crucible to obtain an optimum working temperature. The results obtained by either method are in agreement with those obtained by a modified vacuum fusion method in which CO and CO(2) can both be measured. These methods have been validated by analysis of two standard reference materials.
Manling
L
L
Shanghai Electrical Apparatus Research Institute, Ministry of Machine Building Industry, Shanghai, China.
Meier
T
T
Zhengcai
S
S
Lingye
W
W
Sunming
T
T
Guowei
W
W
Huannan
H
H
Ronghua
Y
Y
Gunadi
Z
Z
Qingren
L
L