Improving Hydration Resistance of MgO-CaO Clinkers by Depositing MgO Coating  

作　　者：YIN Hongfeng LI Botao GAO Kui DING Songxiong 

机构地区：[1]College of Materials and Mineral Resources,Xi'an University of Architecture & Technology [2]Faculty of Science and Engineering,University of Agder

出　　处：《China's Refractories》2016年第3期11-16,共6页中国耐火材料（英文版）

基　　金：supported by The Industrial Research Project of Shaanxi Province , China under Grant No. 2012k07-07

摘　　要：By carbothermal reduction of Mg O with black carbon as reduction agent at a high temperature,Mg O was deposited on the surface of Mg O- Ca O clinker（ as coating） to improve the clinker ＇s hydration resistance. In the paper,effect of deposition temperature and holding time on the hydration resistance of the treated Mg O-Ca O,the deposition mechanism and Mg O coating kinetics were investigated with hydration resistance test,X-ray diffractometry（ XRD） and scanning electronic microscope（ SEM）. Results showed Mg O coating grew in a2D mode on the surface of Mg O- Ca O particles; the Mg O coating improved the hydration resistance of the coated Mg O- Ca O clinker,and the coated clinker would become stronger when coated at higher deposition temperature and longer holding time. The measurements also found that Mg O deposition process varied with the deposition temperature： it was mainly a chemical-controlled process at temperatures between 1 400- 1 500 ℃,with an apparent activation energy（ AAE） of 97. 8kJ·mol^（-1）; it would change into a diffusion-controlled process when the temperature rising to 1 500- 1 600 ℃,with apparent activation energy of 19. 2kJ·mol^（-1）.By carbothermal reduction of Mg O with black carbon as reduction agent at a high temperature,Mg O was deposited on the surface of Mg O- Ca O clinker（ as coating） to improve the clinker ＇s hydration resistance. In the paper,effect of deposition temperature and holding time on the hydration resistance of the treated Mg O-Ca O,the deposition mechanism and Mg O coating kinetics were investigated with hydration resistance test,X-ray diffractometry（ XRD） and scanning electronic microscope（ SEM）. Results showed Mg O coating grew in a2D mode on the surface of Mg O- Ca O particles; the Mg O coating improved the hydration resistance of the coated Mg O- Ca O clinker,and the coated clinker would become stronger when coated at higher deposition temperature and longer holding time. The measurements also found that Mg O deposition process varied with the deposition temperature： it was mainly a chemical-controlled process at temperatures between 1 400- 1 500 ℃,with an apparent activation energy（ AAE） of 97. 8kJ·mol^（-1）; it would change into a diffusion-controlled process when the temperature rising to 1 500- 1 600 ℃,with apparent activation energy of 19. 2kJ·mol^（-1）.

关 键 词：magnesia- calcia clinker hydration re-sistance magnesia coating carbothermal reduction deposition mechanism 

分 类 号：TQ175.1[化学工程—硅酸盐工业]