重金属氢氧化物沉淀强化气浮途径的研究

用压力溶气、分布板分散气体及旋流-充气3种气浮方法分别研究了Cu~(2 )、Ni~(2 )、Cr~(3 )3种重金属离子的氢氧化物沉淀的气浮作用。红外光谱和吸附热结果说明Cu~(2 )和Ni~(2 )的氢氧化物沉淀对十二烷基硫酸钠(SLS)的吸附作用为化学吸附,而Cr~(3 )的氢氧化物沉淀对SLS的吸附为物理吸附。ζ电位对Cu(OH)_2和Ni(OH)_2沉淀的气浮分离效率影响不大,但对Cr(OH)_3沉淀的影响显著,当ζ电位在等电点附近时Cr(OH)_3沉淀的气浮分离率最高。对影响沉淀气浮分离效率的主要因素及其相应的变化规律的研究结果表明:3种金属的氢氧化物沉淀的气浮动力学均可用一级动力学方程描述。发现气泡与氢氧化物沉淀颗粒碰撞粘附过程的表现活化能,可作为衡量气浮过程分离效率的特征参数。

Studies on Forcible FIotation Means for Heavy Metal Hydroxide Precipitates

Flotation process of the precipitates of Cu~(2 ), Ni~(2 ) and Cr~(3 ) hydroxides by conventional dissolved flotation, diffused-air flotation and cyclone-aeration flotation were investigated. The results of IR analysis and thermodynamics studies indica-ted that the adsorption of sodium lauryl surlfate (SLS) by Cu~(2 ) and Ni~(2 ) hydro-xides was chemisorption, while by Cr~(3 ) was physical adsoption. The influence of Zeta potential of Cu(OH)_2 and Ni(OH)_2 on their flotation separation efficiency was insignificant, but for Cr(OH)_3 was significant remarkable and has a maximum nearby isoelectric piont. The results of kinetic studies showed that the flotation of Cu~(2 ), Ni~(2 ) and Cr~(3 ) hydroxides could be deseribed by an first-order reaction equation. A new characteristic parameter, apparent activation energy of attach-ment of the precipitate particles to bubble, has been proposed to describe theseparation effect of flotation process.