赤泥及粉煤灰制备免烧砖的工艺探究

Study on the Preparation Process of Baking-Free Bricks with Red Mud and Fly Ash

赤泥作为氧化铝生产过程中的固体废物,其堆存数量随着氧化铝产量的不断增加而上升,同时其复杂的化学成分、含碱性和含放射性等因素,已造成严重的环境负担.故针对赤泥的利用,本文利用铝厂固体废料赤泥及粉煤灰,并添加石膏、石灰、骨料和水泥等辅助材料制备赤泥-粉煤灰免烧砖.对其工艺过程的陈化时间、成型压力及保压时间进行了探究,并进行了免烧砖性能测试和XRD、SEM分析.实验结果表明:在自然养护条件下,最佳工艺过程的参数为成型压力20MPa,陈化时间7h,保压时间30s;免烧砖抗压强度可达26.76MPa,各性能均达到合格品的生产要求,实现了固废利用.

As solid waste in the production process of alumina,stacking number of red mud raised with the increasing of alumina production,and the factors of its complex chemical composition,alkalinity and radioactivity,has caused a serious environmental burden.Therefore,aiming at the utilization of red mud,the baking-free brick was prepared using the solid waste red mud produced by aluminum plant and fly ash as the main raw material,gypsum,lime,aggregate,cement as auxiliary material.And the process parameters of aging time,forming pressure and holding time,were explored.The performance of brick was tested and the sample was analyzed by using XRD and SEM.The experimental results show that,under natural curing conditions,the optimal process parameters is forming pressure of 20 MPa,aging time of 7 h,holding time of 30 s;the compressive strength of baking-free bricks can reach26.76 MPa,and all performance meet the production requirements of qualified products,solid waste utilization is realized.