本文關(guān)鍵詞： 普通粉煤灰 動態(tài)水熱法 托貝莫來石 晶須　出處：《北京化工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：托貝莫來石型硅酸鈣材料具有市場容量大、強度高、導(dǎo)熱系數(shù)低、容重低等突出優(yōu)勢,在建筑外墻、工業(yè)爐窯等重要節(jié)能領(lǐng)域應(yīng)用前景廣闊。粉煤灰是我國主要固體廢棄物之一,粉煤灰的大量堆積,給我國造成了嚴(yán)重的社會問題和環(huán)境問題。本研究以開發(fā)粉煤灰量大面廣綜合利用途徑為出發(fā)點,并結(jié)合我國節(jié)能減排的重大需求,提出以粉煤灰為硅質(zhì)原料采用動態(tài)水熱法合成托貝莫來石晶體的新方法,重點研究粉煤灰合成托貝莫來石晶須的新工藝及反應(yīng)機理。論文取得的主要創(chuàng)新性進展如下：(1)探索并優(yōu)化了以粉煤灰作為硅質(zhì)原料制備托貝莫來石晶須的新工藝,獲得了最佳的工藝條件：Ca/(Al+Si)摩爾比1.0,反應(yīng)時間5h,反應(yīng)溫度220℃,液固比30mL/g,攪拌強度為200～400rpm。在最佳條件下合成的托貝莫來石為晶須相互纏繞而成的球形二次粒子。(2)深入研究了機械活化對提高粉煤灰反應(yīng)活性的影響機制。研究結(jié)果顯示,機械活化作用后,粉煤灰比表面積大幅提高,反應(yīng)活性點大幅增加,極大地提高了粉煤灰的反應(yīng)活性,使合成的托貝莫來石晶型更加完整,晶須長徑比變大,晶須相互纏繞形成的球形二次粒子表面更加光滑,二次粒子累計孔體積顯著增大,這些變化非常有利于托貝莫來石制品絕熱保溫性能和強度的提高。(3)明晰了粉煤灰合成托貝莫來石的反應(yīng)機理。在反應(yīng)過程中,粉煤灰表面活性Si02優(yōu)先和Ca(OH)2反應(yīng),生成C-S-H凝膠,同時在溶液中OH-的作用下,粉煤灰表面非活性Si02不斷被活化,參與與Ca(OH)2反應(yīng)；生長在粉煤灰表面的這些凝膠,在特定反應(yīng)體系下,不斷晶化、纖維化,并進而相互纏繞成球形二次粒子；粉煤灰中的A1由于與Si性質(zhì)相似,可部分取代[Si04]4-中的硅,取代位置以Q2和Q3位置為主,取代量最高可達16%。由于鋁的取代作用,使得這種含鋁托貝莫來石耐熱溫度比純托貝莫來石高出90℃。
[Abstract]:Tobe mullite calcium silicate material with large market capacity, high strength, low thermal conductivity, low bulk density and other outstanding advantages in the building exterior wall, Fly ash is one of the main solid wastes in China. This study is based on the development of comprehensive utilization of fly ash on a large scale and on the basis of the great demand for energy saving and emission reduction in China. A new method for the synthesis of Tobiamurite crystals by dynamic hydrothermal method using fly ash as siliceous raw material is proposed. The new technology and reaction mechanism of the synthesis of Tobiamurite whisker from fly ash are studied. The main innovative progress in this paper is as follows: 1) the new process of preparing toberamulite whisker with fly ash as siliceous raw material has been explored and optimized. The optimum reaction conditions were obtained as follows: mole ratio of 1: Cao / Al Si = 1.0, reaction time 5 h, reaction temperature 220 鈩，

本文編號：1495821