粉煤灰提取氧化铝方法研究

Study on the Methods of Leaching Alumina from Fly Ash

粉煤灰中氧化铝含量一般为17% ~ 35%,高则可达40% ~ 60%,高铝粉煤灰有潜力成为铝土矿的替代铝资源。粉煤灰提铝技术的开发,对于改善环境、实现资源优化配置具有重要意义,本文对循环流化床粉煤灰和煤粉炉粉煤灰的形成机理进行了探讨,循环流化床粉煤灰的结晶性较差,主要以非晶相为主,存在少量莫来石和氧化铝等结晶相,而煤粉炉粉煤灰结晶性较好,主要结晶相为莫来石和刚玉,以及少量的非晶相SiO_2。针对不同种类的粉煤灰,对目前酸法、碱法、硫酸铵法等不同方法提取粉煤灰的工艺进行了比较和探讨。

The alumina content in fly ash generally is 17%~35%,even 40%~60%,and high alumina fly ash is a potential alumina resource instead of bauxite.The development of technology in recovering alumina from fly ash is very important for environment improvement and resource distribution optimization.The formation of CFB and oF fly ash was studied,the main phase of CFB fly ash was amorphous phase with few crystalline phase of mullite and Al2O3,while the main phase of oF fly ash was mullite and corundum with few amorphous phase,the different methods of extracting alumina from fly ash were discussed,such as acid leaching method,alkali method,Ammonium sulfate roasting process.