Reactions of Hydrogen and Oxygen with Copper Melts Measured with a Modified CHAPEL Technique

The CHAPEL technique (continuous hydrogen analysis by pressure evaluation in liquids) measures directly the hydrogen pressure built up in an evacuated sensor volume immerged in an aluminum melt. In copper melts, the gas phase in the CHAPEL sensor consists of a mixture of hydrogen and carbon monoxide. A modified sensor system equipped with a PdAg diffusion cell measures continuously the total pressure and in addition the hydrogen partial pressure. The total pressure in the evacuated sensor volume increases slowly over many hours depending on the parameters defined by the experimental setup and the conditions of the melt. However, the hydrogen pressure approaches an equilibrium state after some time. Transport parameters for hydrogen and oxygen in the melt can be studied by doping the melt with gases introduced by a separate doping cell or after reactions of the melt or the coal bed on top of the melt with H O or organic materials.