Research on the formation of new functional materials from rice husk fired power pilot plant ashes

利用稻壳燃烧发电的电厂已经在泰国等两个或多个国家开始运行，有望成为未来的生物质能之一，但大量排放的燃烧灰的处理一直是一个严重的问题。对稻壳灰分进行了表征，目的是为了进一步利用稻壳灰分，并以这些稻壳灰分为原料形成一种新材料。因此，灰烬由高结晶度的方石英组成，纯度超过92%。由于方石英的溶解速度比硅胶和石英快，因此具有高的硅肥性能。以稻壳灰为原料，在适当条件下热处理，制得高结晶、高纯度、几乎不含碳的方石沸石。通过处理稻壳灰与氢氧化钠溶液反应，并进行水热处理，得到各种高功能材料FAU （faujasite）和LTA型沸石，以及纤维状的imogolite晶体。所得沸石样品的结晶度、离子交换能力和微孔体积均与市售同类沸石相当。由于本研究所用稻壳灰样品具有高纯度硅酸材料的特点。所得铁长石不仅对铜、镉、铅离子等阳离子具有较高的吸附性能，而且对铬酸离子、砷酸离子等阴离子也具有较高的吸附性能。所得材料在环境净化等方面效果显著。

Power generation plants operated by burning rice husk has already worked in two or more countries, such as Thailand, and can be expected as one of the future biomass energy, however, the processing of a lot of combustion ashes discharged from there has been a serious problem. Characterization of the ashes was performed for the purpose of advanced use and the formation of a new material by using these rice husk ashes as a starting material. Consequently, the ashes was composed by cristobalite of high crystallinity beyond purity 92wt%. Since dissolution speed of a cristobalite is quicker than silica gel and quartz, it turns out that it has the performance high as silica fertilizer. The cristobalite of high crystalline and high purity to which carbon hardly remains was obtained by heat-treating on suitable conditions by using these rice husk ashes as starting materials. By processing the rice husk ashes reacted with sodium hydroxide solution, and carrying out hydrothermal treatment, various kinds of high functional materials as a FAU (faujasite) and a LTA type zeolites, and the fiberous crystal of an imogolite. The obtained zeolite samples show have equivalent crystallinity, ion exchange ability and micropore volumes comparing with the commercial same type zeolites. As the rice husk ashes sample used by this research have the character which is a high purity silicic acid materials. Moreover, the obtained imogolite showed high adsorption nature not only cations such as copper, cadmium, and lead ion, but anion as chromium acid ion, and arsenic acid ion. These obtained materials are effective on environmental purification, etc.