高压溶出硅质结疤物的形态结构研究

A Research on Morphology Structure of Siliceous Scab in Process of High Pressure Digestion

利用工艺矿物学研究手段,对氧化铝生产高压溶出过程硅质结疤物的形貌结构进行深入研究,从而为预防和治理硅结疤提供了理论依据。研究结果表明:单套管预热器中硅质结疤物为钠硅质渣,呈微细粒状,与铝针铁矿一起填充在晶形规整、晶体粗大的赤铁矿晶体间的空隙里;压煮器中硅质结疤物为少量的微细粒钠硅质渣,与氢氧化镁基体共同沉积于钛的第一沉积旋回的层间局部;停留罐中硅质结疤物以水化石榴子石和橄榄石为主,它们以微细粒状填充于针铁矿晶体间隙中,有少量针状碳酸钠及钠硅渣;闪蒸器中硅质结疤物主要是铁石榴子石和Na2Ca3Si3O10相,前者与Al2O3(Al2O3·3H2O)共生成为球粒状结构中填隙物的主要成分,后者以微细粒状与氢氧化铝相混合成为纹层状结构中的主要成分。

Morphology structures of siliceous scabs in the process of high pressure digester is studied by technological mineralogy methods for theroretically preventing and controlling. Results show that siliceous scabs in single tube preheater are fine granular sodium silicon slag, with filling in gaps between neat and bulky hematite crystals by alumogoethite. Siliceous scabs in autoclave are small quantity of fine granular sodium silicon slag, and coprecipitate between local interlayers in the first sedimentary cycle of Ti with magnesium hydroxide matrix. Siliceous scabs in stay ladle are mainly hydrated garnet and olivine with micro-fine particle, filling in goethite crystal clearance, accompanied by a small amount of needle sodium carbonate and sodium silicon slag, while siliceous scabs in flash type evaporator are mainly iron garnet and Na2Ca3Si3O10 Phase. The former, a filler content, is symbiotic with Al2O3(Al2O3·3H2O), and the latter, a fine granular, blends with Al(OH)3 as the main ingredient in spherulitic and layered structure respectively.