中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 28 No. 9 September 2018 |
（1. School of Metallurgy, Northeastern University, Shenyang 110819, China;
2. Liaoning Key Laboratory for Metallurgical Sensor and Technology, Northeastern University, Shenyang 110819, China;
3. School of Environmental and Chemical Engineering, Shenyang Ligong University, Shenyang 110159, China;
4. Science and Technology Laboratory, Academy of Environmental Sciences of Panjin City, Panjin 124401, China）
Abstract:The reaction kinetics of roasting zinc silicate using NaOH was investigated. The orthogonal test was employed to optimize the reaction conditions and the optimized reaction conditions were as follows: molar ratio of NaOH to Zn2SiO4 of 16:1, reaction temperature of 550 °C, and reaction time of 2.5 h. In order to ascertain the phases transformation and reaction processes of zinc oxide and silica, the XRD phase analysis was used to analyze the phases of these specimens roasted at different temperatures. The final phases of the specimen roasted at 600 °C were Na2ZnO2, Na4SiO4, Na2ZnSiO4 and NaOH. The reaction kinetic equation of roasting was determined by the shrinking unreacted core model. Aiming to investigate the reaction mechanism, two control models of reaction rate were applied: chemical reaction at the particle surface and diffusion through the product layer. The results indicated that the diffusion through the product layer model described the reaction process well. The apparent activation energy of the roasting was 19.77 kJ/mol.
Key words: reaction mechanism; kinetics; Zn2SiO4; NaOH roasting; reaction process; phase transformation
