預熱過程結疤的影響
(鄭州輕金屬研究院 氧化鋁研究室， 鄭州 450041)
摘 要: 提出了在一水硬鋁石型鋁土礦漿預熱過程中含硅、含鈦及含鎂礦物的結疤機理，在此基礎上深入研究了石灰添加方式對結疤過程的影響規(guī)律。石灰在礦漿進入預熱過程前加入時，由于水化石榴石的生成使含硅礦物結疤速度降低，同時由于礦漿中存在較多的Mg(OH)2，有利于其在礦漿中Mg(OH)2固相的表面析出，可在一定程度上減緩Mg(OH)2結疤的生成。石灰在礦漿預熱過程之后加入， 不僅不能避免CaTiO3結疤的生成，同時還有鈦酸鈉結疤出現(xiàn)。同時，石灰前加還有利于預脫硅過程中脫硅率及脫鈦率的提高。因此，石灰前加即石灰和礦石一起入磨或者將石灰乳加入預脫硅系統(tǒng)，有利于減緩礦漿預熱過程中的結疤速度。
關鍵字: 一水硬鋁石型鋁土礦； 拜爾法； 預熱過程； 結疤； 石灰； 添加方式
scaling process in Bayer preheating process
of diasporic bauxite slurry
（Alumina Research Department，Zhengzhou Light Metal
Research Institute，Zhengzhou 450041， P.R.China）
Abstract: The scaling mechanism of Si-containing， Ti-containing and Mg-containing minerals in Bayer preheating process of diasporic bauxite slurry was proposed. The effect of lime adding method on the scalingprocess was deeply studied. If lime was added to slurry before preheated, the scale formations of Si-containing minerals and Mg(OH)2 were decreased and restrained because of the production of hydrogarnet and a large amount of Mg(OH)2 in solid phase in slurry. If lime was added to preheated slurry, the scale formation of CaTiO3 can not be avoided and the sodium titanate scale was produced. In addition，adding lime to slurry before preheated was beneficial to increasing the desilication and detitanation efficiency in predesilication process. Therefore，grinding lime with bauxite or adding lime to slurry in predesilication process can slow down the general scaling rate in preheating process of slurry.
Key words: diasporic bauxite; Bayer process; preheating process; scaling process; lime; adding method
