Structural Investigation of Hydrogen in Calcium Silicate and Fluorosilicate Slags

Hydrogen absorption of lime-silicate and -fluorosilicate slags, which were produced at 1600℃ under Ar+water vapor (PH_2=0.128atm.) atmosphere, was investigated. State of hydrogen in these slags was also investigated by infrared absorption method. In lime silicate slag, a minimum was observed near 50mol% SiO_2 in the dependence of total hydrogen content on slag composition. Three absorption bands were observed at 2.9 μ (band 1), 3.4 μ (band 2) and 4.2 μ (band 3) as the result of resolving every corrected absorption spectrum by computor calculation. These three bands were assigned to nearly free hyroxyl and hydroxyls of OH…O^- and OH…O°types from the dependence of each band on slag composition. Three absorption bands in calcium flurosilicate slags were observed at similar positions. CaF_2 addition to lime silicate slags was effective to lowering hydrogen absorption into the slags when its content was about 7mol% or over. In calcium fluorosilicate slags with high initial CaF_2 content, however, CaF_2 addition showed harmful effect to lowering hydrogen content in the slags on account of formation of active non-bridged oxygen when CaF_2 content became less than 7mol% or so.