Kinetic aspects of the thermal decomposition of zinc carbonate

Effect of Co2 Partial Pressure on the Thermal Decomposition Kinetics of Zinc Carbonate Hydroxide

“…As the CO 2 partial pressure is increased, the activation energy approaches a mean value of 180 ± 5 kJ/mol. Other researchers studying similar reactions in air have found activation energies of 94 ± 9 kJ/mol [9] and 88.7 kJ/mol [10]. These values are obtained in the absence of CO 2 in the experiment atmosphere.…”

“…Based on TG results, they have proposed two different mechanisms for the nucleation and growth of products. Dollimore et al [9] have found an activation energy value of 94±9 kJ/mol for the calcination reaction of zinc carbonate hydroxide in the temperature range of 200 -260 o C. Nobari and Halali [10] have studied the calcination kinetics of zinc carbonate hydroxide and Calsimin zinc carbonate concentrate and have reported the activation energies to be 88.7 kJ/mol and 97.3 kJ/mol, respectively. Unlike zinc carbonate, the effect of CO 2 partial pressure on the calcination reactions of calcium carbonate, cadmium carbonate, manganese carbonate and lead carbonate has been studied by many investigators [11][12][13][14][15].…”

Preparation and characterization of zinc hydroxide carbonate and porous zinc oxide particles

“…One of the earlier studies on the thermal decomposition of hydrated zinc carbonate (ZnCO 3 ·2ZnO·2H 2 O) was performed by Dollimore et al 13 On the basis of isothermal TG in the temperature range 200-260 • C they reported an activation energy of 94 ± 9 kJ/mol for two thermally overlapping stages during the decomposition. On the basis of DTA results Chen et al 14 reported a single step decomposition process with an activation energy of 113 kJ/mol for thermal decomposition of Zn 4 CO 3 (OH) 6 ·H 2 O.…”

On the formation of nanocrystalline active zinc oxide from zinc hydroxide carbonate

“…The mechanism and kinetics of the thermal decomposition of Zn 5 (CO 3 ) 2 (OH) 6 and similar zinc hydroxide carbonates have been investigated previously (Nobari and Halali, 2006, Li et al, 2005, Liu et al, 2004, Kanari et al, 2004, Sawada et al, 1996, Dollimore et al, 1980, Castellano and Matijevic, 1989. Although the decomposition is energetically favourable above about 160 °C (Moezzi et al, 2012), at that temperature the reaction takes hundreds of hours to complete (Kanari et al, 2004).…”

“…The kinetics can be explained with a shrinking core model (Nobari and Halali, 2006) but there has been discussion in the literature on whether a one-or two-step model for the decomposition is required (Li et al, 2005, Kanari et al, 2004. Nevertheless, it is generally observed that de-carboxlation and de-hydroxlation occur simultaneously (Nobari and Halali, 2006, Li et al, 2005, Liu et al, 2004, Kanari et al, 2004, however these processes may be separate in the specific case of the calcination of ZnCO 3 •ZnO•2H 2 O (Dollimore et al, 1980). The particle size of the ZnO produced is normally in the range 20 to 30 nm and some dependence of particle size and/or crystallinity on temperature was noted (Li et al, 2005).…”