加碱煅烧活化粉煤灰工艺参数研究

Study on process parameters for activating fly ash with alkali by calcination

研究了以碳酸钠为助剂活化粉煤灰的煅烧工艺。采用滴定法测定不同煅烧条件(煅烧温度和煅烧时间)所得活化粉煤灰溶解在氢氧化钠溶液中的硅、铝浓度,并采用X射线衍射(XRD)表征不同煅烧条件(灰碱质量比)所得活化粉煤灰的物相组成,得出粉煤灰较佳煅烧工艺参数:煅烧温度为875℃,保温时间为1.5 h,粉煤灰与碳酸钠的质量比为1∶0.87。煅烧后的产物主要以可溶性的硅铝酸钠(NaAlSiO4)和硅酸钠(Na2SiO3)为主,原粉煤灰中的石英、莫来石基本消失,粉煤灰得到充分活化。

The calcination process for activating fly ash with Na2CO3 as accessory ingredient was investigated.The concentations of Si and A1 in the fly ash activated under different calcination conditions （calcination temperature and calcination time）, that dissolved in the sodium hydroxide solution were measured by titering process.The phase composition of fly ash obtained under different calcination conditions（mass ratio of fly ash and sodium carbonate） was characterized by XRD.The best process parameters were obtained as follows ： calcination temperature was 875 ~C, holding time was 1.5 h, and mass ratio of fly ash and sodium carbonate was 1：0.87.The products after calcination were mainly made up of soluble NaA1SiO4 and Na2SiO3, and the quartz and mullitein in the raw fly ash both almost disappeared.Therefore, the fly ash was activated adequately.