太阳能级多晶硅尾气回收液相二氧化硅提纯

Purification of Liquid Phase Silicon Dioxide from Reclaiming Tail Gas of Solar Polysilicon Production

亚洲(青海)硅业引进西门子法生产多晶硅时所产生的尾气回收液相二氧化硅没有利用,而是直接被填埋,不仅浪费了能源和原材料,而且对环境造成污染。从节约能源和环保的角度考虑,必须对尾气进行回收再利用。本文对亚洲(青海)硅业引进西门子法生产太阳能级多晶硅尾气回收液相二氧化硅进行提纯实验。结果表明,影响二氧化硅纯度的主要因素是加热减量和灼烧减量;该样品除了含有一定量的水分外,还含有一定的灰分和挥发份,主要来源是除二氧化硅外四氯化硅的水解产物,还有部分硅胶,其在高温加热时失水产生二氧化硅粉,同时二氧化硅表面吸附了少量未水解的硅氯化物,在加热时挥发,本方法得到的二氧化硅含量均大于99.8%以上的粉体;从样品形貌可以看出,团聚使样品粒度增大。

Liquid phase silicon dioxide produced while reclaiming tail gas of solar polysilicon production by Siemens is not used in Asia Silicon industry（Qinghai）,but directly put to landfill,which not only is a waste of energy and raw materials,but also pollutes the environment.Therefore,in view of energy conservation and environmental protection,the gas should be recycled.This paper studies the properties of liquid phase silicon dioxide produced while reclaiming tail gas of solar polysilicon production by Siemens in Asia Silicon Industry（Qinghai）.It is shown that the major factors that influence the purity of silicon dioxide are the heating loss and the burning loss;in addition to an amount of water,the samples contain some amount of ash and volatile,coming mainly from the hydrolysis of silicon tetrachloride,as well as some silica-gel.The silica-gel will lose water and the product silicon dioxide powder when heated to a high temperature.When the silicon dioxide adsorbs a small amount of hydrolysis of silicon chloride on its surface,it will volatile when heated.With this kind of method one can get powders of 99.8% silicon dioxide.In the morphological observation,it can be seen that the particle size increases by agglomeration.