烧结法高浓度铝酸钠溶液中硅酸二钙的絮凝机理  

Flocculation mechanism of dicalcium silicate in concentrated sodium aluminate solutions by sintering process

作　　者：刘桂华[1] 黄亚军[1] 彭志宏[1] 周秋生[1] 李小斌[1] 

机构地区：[1]中南大学冶金科学与工程学院,长沙410083

出　　处：《中国有色金属学报》2010年第10期2051-2056,共6页The Chinese Journal of Nonferrous Metals

基　　金：国家重点基础研究发展计划资助项目(2005CB623702)

摘　　要：通过测定硅酸二钙与高浓度铝酸钠溶液(ρ(Al2O3)≥180g/L)反应后浆液的絮凝沉降性能,结合红外光谱、Zeta电位和接触角的测定结果,探讨絮凝剂与硅酸二钙的絮凝机理。沉降实验结果表明:添加含酰胺基、羧基的絮凝剂A和B时,浆液不絮凝沉降;而含酰胺基、羧基和羟肟酸的絮凝剂C的沉降效果好,沉降初始5min的平均速度达到19.0mm/min。红外光谱分析结果表明:添加絮凝剂A、B和C后,絮凝剂中的R—COO-基团均可与硅酸二钙中的Ca2+形成配位键。沉降后固相的有机碳含量分析结果表明:硅酸二钙可吸附约40%的絮凝剂A和B,或吸附91.04%的絮凝剂C,这直接导致吸附絮凝剂C的硅酸二钙的Zeta电位、接触角和固体表面能变化较絮凝剂A、B的大;在烧结法高浓度体系中,电中和脱稳不是主要原因,絮凝剂在颗粒表面的大量被吸附并通过疏水力增强或架桥作用的形成是改善浆液絮凝沉降的关键。The settlement properties of dicalcium silicate in the concentrated solutions（ρ（Al2O3）≥180 g/L） were measured with addition of different flocculants by sintering process,and then the flocculation mechanism was discussed based on the analysis of infrared spectrum,Zeta potential and contact angle.The results of settlement experiment show that no flocculation occurs with adding either flocculant A or B containing amide groups and carboxyl groups,while flocculation appears much better and the average settlement rate of slurry reaches 19.0 mm/min in the first 5min after adding flocculant C containing amide groups,carboxyl groups and hydroxamic acid groups.And the IR results indicate that R—COO- in flocculant A,B or C easily forms coordination bond with Ca2＋ in dicalcium silicate.Meanwhile dicalcium silicate absorbs 91.04% of flocculant C but about 40% of flocculant A or B during the settling process by the analysis of organic carbon content in solid,resulting in that the variations of Zeta potential,angle contact and solid surface energy of dicalcium silicate absorbing flocculant C are more than those absorbing flocculant A or B.These facts imply that more adsorption of flocculants onto dicalcium silicate favors the flocculant formation by hydrophobic interaction and bridge action instead of the charge neutralization.

关 键 词：硅酸二钙 铝酸钠溶液 烧结法 絮凝机理 

分 类 号：TF803.2[冶金工程—有色金属冶金]