“…According to the thermodynamic calculations of Taskinen and Janke, [49] it is evident that in the presence of hot metal saturated with carbon, the stable form of Na 2 CO 3 is Na in a gaseous form. [49] However, as suggested by Kim et al, [50] in the presence of SiO 2 , Na 2 CO 3 is thermodynamically favored to decompose into Na 2 SiO 3 and only a small fraction of initial Na 2 CO 3 is decomposed into Na-gas if no carbon is available for the reaction, which is consistent with the results of Pak et al [32] In addition to this, as the rate of evaporation is controlled by either the rate of mass transfer or chemical reaction, the effect Na 2 O-loss on the sulfide capacity is rather small, but assumedly not negligible. [2,3,51,52] The evaporation rate of Na 2 O from the slag in the presence of carbon was studied by Li et al [51] in temperatures between 1300°C (1573.15 K) and 1500°C (1773.15 K).…”