烧结法赤泥的矿物学特征与快速固化机理

Characteristics and Rapid Hardening Mechinsm of Red Mud from Alumina Production with Sintering Process

采用DTA-TG、XRD、扫描电镜及能谱等方法,系统分析了烧结法赤泥在不同条件堆存过程中质量损失、含碳量与含水量变化、物相组成、化学成分等特征及快速固化机理。赤泥中钙的氢氧化物最容易转化为碳酸钙,此作用可使赤泥获得早期强度。硅酸二钙水化速度缓慢,不可能靠它的水化在较短时间内获得明显的强度。添加石膏或适量硫酸形成硫酸钙和钙矾石等途径来获得赤泥的早期强度是可能的,而长期堆存过程中通过硅酸二钙的缓慢水化及压实作用则可使堆存赤泥获得更高的整体强度。

The mass loss, C and water content changes, phase composition and chemical ingredient of red mud from alumina production with sintering process during the preservation process, and the mechanism of rapid hardening are analyzed by the measures of DTA-TG, XRD, and Scanning Electron Microscope. The calcium hydroxide is easily transformed to calcium carbonate, this results in the early strength of the red mud heap. The hydrating rate of dicalcium silicate is slowly, the remarkably initial strength of red mud heap can not be achieved by this process. It is possible to accomplish the rapid hardening of the red mud by the formation of calcium sulfate and entringite through addition of gypsum or sulfuric acid. The integer strength of the red mud heap is gradually realized by the slowly hydrating process of dicalcium silicate and the natural pressing effect along with the preservation process.