The volatilization kinetics of senarmontite(Sb_(2)O_(3))was analyzed in a neutral atmosphere in two temperature ranges:550-615°C(roasting temperature)and 660-1100°C(melting temperature)by using a thermogravi...The volatilization kinetics of senarmontite(Sb_(2)O_(3))was analyzed in a neutral atmosphere in two temperature ranges:550-615°C(roasting temperature)and 660-1100°C(melting temperature)by using a thermogravimetric analysis method under various gas flow rates and using a 1.3 m L ceramic crucible(11 mm in internal diameter and 14 mm in height).The effect of particle size was also analyzed.The experimental results of mass loss data,X-ray diffraction(XRD)analysis of partially reacted samples and thermodynamic studies indicate that the senarmontite becomes volatile in the form of Sb_(4)O_(6)(g)without the formation of any intermediary compound in the entire temperature range.At roasting temperatures,the volatilization kinetics of Sb_(2)O_(3) was analyzed using the model X=kappt.The volatilization reaction was controlled by the surface chemical reaction and an activation energy value of 193.0 k J/mol was obtained in this temperature range.Based on the volatilization kinetics at the melting temperatures,for linear behaviour in nitrogen gas,kinetic constants were determined,and an activation energy of 73.9 k J/mol was calculated for the volatilization reaction with a surface area of 8.171×10^(-5)m^(2).展开更多
文摘The volatilization kinetics of senarmontite(Sb_(2)O_(3))was analyzed in a neutral atmosphere in two temperature ranges:550-615°C(roasting temperature)and 660-1100°C(melting temperature)by using a thermogravimetric analysis method under various gas flow rates and using a 1.3 m L ceramic crucible(11 mm in internal diameter and 14 mm in height).The effect of particle size was also analyzed.The experimental results of mass loss data,X-ray diffraction(XRD)analysis of partially reacted samples and thermodynamic studies indicate that the senarmontite becomes volatile in the form of Sb_(4)O_(6)(g)without the formation of any intermediary compound in the entire temperature range.At roasting temperatures,the volatilization kinetics of Sb_(2)O_(3) was analyzed using the model X=kappt.The volatilization reaction was controlled by the surface chemical reaction and an activation energy value of 193.0 k J/mol was obtained in this temperature range.Based on the volatilization kinetics at the melting temperatures,for linear behaviour in nitrogen gas,kinetic constants were determined,and an activation energy of 73.9 k J/mol was calculated for the volatilization reaction with a surface area of 8.171×10^(-5)m^(2).
