蛭石在低浓度盐酸和硫酸中的溶出性比较研究

Comparison of dissolution of vermiculite in low concentration hydrochloric acid and sulfuric acid

蛭石作为三八面体层状硅酸盐矿物,由于其独特的层状结构被广泛应用于各领域.酸处理蛭石能提高蛭石的比表面积,改变层电荷数,达到增加表面活性官能团的目的.以新疆尉犁蛭石为原料,在低浓度盐酸和硫酸界面进行溶出性比较研究,对原料及酸浸后样品的物相、结构、微观形貌以及浸出液中各离子浓度进行表征分析.结果表明:在酸浓度较低时盐酸和硫酸对蛭石的酸蚀程度相当,在酸浓度稍微增加时硫酸对蛭石的酸蚀速度快于盐酸.两种酸的蛭石结构中各金属离子浸出的难易顺序一致,均为:层间物>八面体片>四面体片.Ca^(2+)作为层间阳离子在酸浸前4 h的溶出速率远大于八面体阳离子Mg^(2+)和四面体阳离子Al^(3+),且层间物中Ca^(2+)相比于K^(+)更容易浸出.适当的酸处理可以提高蛭石的阳离子交换容量.本文对于蛭石的利用开发具有一定意义.

As a trioctahedral layered silicate mineral,vermiculite is widely used in various fields due to its unique layered structure.Acid treatment of vermiculite can increase the specific surface area of vermiculite,change the number of layer charges and increase the surface active functional groups.Using Xinjiang Yuli vermiculite as raw material,the comparative study of dissolution of vermiculite at the interface of low concentration hydrochloric acid and sulfuric acid was carried out.The phase,structure,spectral characteristics,microstructure and concentration of ions in the leaching solution of the raw materials and the samples after acid leaching were characterized and analyzed.The results show that the degree of vermiculite corrosion by HCl and H_(2)SO_(4) is similar at low acid concentration,and the rate of vermiculite corrosion by sulfuric acid is faster than that by HCl at slightly increased acid concentration.The order of leaching difficulty of each metal in vermiculite structure is the same as that of interlayer>octahedral sheet>tetrahedral sheet.The dissolution rate of Ca^(2+)as interlayer cation at 4 hours before acid leaching was much higher than that of octahedral cation Mg^(2+)and tetrahedral cation Al^(3+),and Ca^(2+)is easier to leach from interlayer than K^(+).Appropriate acid treatment can improve the cation exchange capacity of vermiculite.This paper has certain significance for the utilization and development of vermiculite.