粉煤灰中玻璃体含量的化学物相分析  

Chemical Phase Analysis of Glass Content in Fly Ash

作　　者：侯新凯[1] 梁爽[1] 刘柱燊 张锦 黄瑞涛 武志江 

机构地区：[1]西安建筑科技大学材料与矿资学院,西安710055

出　　处：《硅酸盐通报》2017年第11期3587-3594,共8页Bulletin of the Chinese Ceramic Society

基　　金：陕西省自然科学基础研究计划项目(2016JM5010);山西省科技创新项目(2013101038);陕西省教育厅专项科研计划项目(15JK1396)

摘　　要：为快速评判粉煤灰的火山灰反应活性和分析其加工过程中技术特征,需准确测定粉煤灰中玻璃体含量。通过分析粉煤灰中各种矿物相在碱、酸溶液中溶解反应特征,提出碱-酸两段溶解来测定粉煤灰中玻璃体含量的化学物相分析法。粉煤灰中莫来石、石英、磁铁矿、赤铁矿和未燃尽碳粒,在碱、酸溶液中是稳定相;玻璃体和f-CaO在碱溶液中反应形成凝胶,凝胶在酸溶液中完全溶解,两者含量为溶解过程的质量缩减率,减去f-CaO含量即为玻璃体含量。测定操作要点,-20μm粉煤灰在90℃20%NaOH溶液溶解2.5 h,溶解1.5 h时湿磨至-12μm。碱溶解后滤渣在30℃10%的HNO_3溶液溶解1.0 h。试样与试剂比例为5 g粉煤灰、500 mL NaOH溶液、200 mL HNO_3溶液。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% Na OH 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% HNO_3 solution with 30 ℃ for 1. 0 h. The mixing ratio of the sample and two solutions was 5 g fly ash,500 mL Na OH solution,200 mL HNO_3 solution.

关 键 词：粉煤灰 玻璃体含量 选择性溶解 碱溶解 HNO3溶液 

分 类 号：O658.6[理学—分析化学]