关键词: 粉煤灰;玻璃体含量;选择性溶解;碱溶解;HNO3溶液

Abstract: Glass content in fly ash is demanded to be measured accurately,for assessment of its pozzolana activity and evaluation technical characteristics in the processing of fly ash in time. A new chemical phase analysis was prepared based on solubility of individual mineral in fly ash,in which test procedure fly ash dissolved by alkaline solution and acidic solution successively. Mullite,quartz,magnetite,hematite and unburn carbon grain in fly ash are inert with alkaline solution and acidic solution. The glass and f-CaO can form gel firstly activated in alkaline solution,then the gel was completely dissolved in acidic solution. The two phases disappeared after the process,and they were loss by dissolution. Glass content equals to the value minus f-CaO content. Determination of glass content in fly ash should follow the following procedures that fly ash in which particle size less than 20 μm firstly should be immersed in 20%NaOH solution at 90 ℃ for 1. 5 h,then it had to be immersed in the solution again for 1. 0 h after the sample was wetly grounded to -12 μm size,finally the filter residue by the alkaline dissolution must be dissolved in 10%HNO3 solution with 30 ℃ for 1. 0 h. The mixing ratio of the sample and two solutions was 5 g fly ash,500 mL NaOH solution,200 mL HNO3 solution.

Key words: fly ash;glass content;selective dissolution;alkaline dissolution;HNO3 solution