Abstract
A study was made of vacuum heating method up to 1200°C, and vacuum fusion method up. to 1800°C in a graphite or Mo crucible for determination of hydrogen content in steelmaking slag. To analyse the gas extracted by vacuum fusion of the specimen, thermoconductivity method was applied, the accuracy of which was improved by means of new type thermocon-ductivity cells, made from thin Cu tubes dipped in ice water which was stirred by an impeller and separated from. contact with ice by a network. The followfng conclusions were reached:
1) Hydrogen in steelmaking slag could not be extracted completely by vacuum heating only up to 1200°C for complete extraction of hydrogen. It should be heated to above 1400°C or its melting Point
.2) H2O in the specimen was quantitatively decomposed in the vacuum furnace and extracted as H2 when it was melted in a graphite crucible. This fact was confirmed by extracting H2 in minerals such as gypsum and actinolite.
3) Strong adsorption of H2 caused by vaporization of reduced material of slag specimen in the vacuum furnace was found, when it was heated at high temperature in a graphite crucible. The effect was minimized, on the contrary, when a Mo crucible was used.
