炭酸ナトリウムおよびそのシリカ混合物の熱または炭素による分解反応

概要

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The decomposition rate of Na_2CO_3 melts in the temperature range from 1200 to 1700℃ under argon atmosphere was measured by using a thermobalance. Significant weight loss of the melt was observed adove 1300℃. The rate at a steady state was given as ω=9.66×10^2 exp (-58600/RT) (g/cm^2・). The reaction scheme was concluded from this equation to be Na_2CO_3(l)→Na_2O(l)+CO_2(g), Na_2O(l)→2Na(g)+1/2 O_2(g). The rate-determining step was the diffusion of reaction products in argon. The reduction of premelted Na_2CO_3-SiO_2 mixtures with graphite at about 1200℃ was examined. Residual Na_2CO_3 in the premelted mixture was completely decomposed by the reaction : Na_2CO_3(l)+2C(s)→2Na(g)+3CO(g). No substantial reduction was observed for sodium metasilicate, Na_2O・SiO_2, dissolved in the premelted mixture. Excess Na_2O over 1 mol per 1 mol SiO_2 was decomposed by carbon : Na_2O(l)+C(S)→2Na(g)+CO(g). Dense fume rising in the reaction furnace was observed during the reaction with graphite. This fume would be originated from the sodium vapour produced as the reaction product in the above reaction. Some experimental results were presented on the removal of carbon dissolved in liquid iron by Na_2CO_3-SiO_2 mixtures.
1980-12-01