水热条件下钾长石的分解反应机理  

REACTIVE MECHANISM OF POTASSIUM FELDSPAR DISSOLUTION UNDER HYDROTHERMAL CONDITION

作　　者：聂轶苗[1] 马鸿文[1] 刘贺[1] 张盼[1] 邱美娅[1] 王蕾[1] 

机构地区：[1]中国地质大学矿物材料国家专业实验室,北京100083

出　　处：《硅酸盐学报》2006年第7期846-850,867,共6页Journal of The Chinese Ceramic Society

基　　金：矿物材料国家专业实验室开放基金(04103)资助项目

摘　　要：实验研究了以氧化钙为助剂在水热条件下的钾长石的分解反应过程及反应机理。研究结果表明:在碱性条件下,钾长石的分解反应具有化学反应控制的特征。搅拌速率对反应速率无明显影响,但通过提高反应温度、提高n(Ca)/n(Al+Si)比值、减小钾长石的粒度3种途径,可以明显提高钾长石的分解率。钾长石的分解反应并不是简单的离子交换作用,而是在碱金属离子与水作用的基础上,反应物中的活化离子OH–与矿物表面的碱金属离子K+,Na+,Ca2+等作用,首先形成表面富硅贫铝的前驱聚合体(SiO2·nH2O)·,然后这些前驱聚合体分解,生成最终产物雪硅钙石。在水热条件下钾长石的分解率最高可达89.01%。The process and mechanism of dissolution reaction of potassium feldspar with CaO as the reactant in a hydrothermal system were studied. The experimental results show that the reaction is controlled by a chemical reaction under alkaline conditions. The stirring rate has a little affect on the dissolution rate. The dissolution rate could be improved by raising the reaction temperature, increasing the mole ratio of n（Ca）ln（Al＋Si） and decreasing the granularity of potassium feldspar particles. The reactive mechanism of the dissolution can not be explained solely on the basis of ion exchange. On the basis of the reaction of alkali ions with water, the dissolution of potassium feldspar in hydrothermal system is due to the effect of active hydroxyl ions on alkali ions, such as K^＋, Na^＋, Ca2^＋, on the mineral grain surface. First Si-rich/Al-deficient precursor polymers （SiO2.nH2O） were produced on the surface, and then the precursor polymers decomposed. At last, the decomposition of the precursor polymers occurred to form the final product——tobermorite. The dissolution rates of potassium feldspar by hydrothermal method can reach a maximum of 89.01%.

关 键 词：水热条件 钾长石 分解反应 反应机理 

分 类 号：TD9[矿业工程—选矿]