胶磷矿浮选体系中硅酸钠的分散机理及第一性原理分析

通过单矿物沉降试验,考察了弱碱性条件下硅酸钠对微细粒胶磷矿分散行为的影响,结果表明,pH=8.5时,随硅酸钠浓度增大,胶磷矿矿物颗粒分散效果逐渐增大,当硅酸钠浓度为800 mg/L时,胶磷矿分散率可达40％,且颗粒能稳定分散.Zeta电位分析结果表明,随硅酸钠浓度增大,胶磷矿表面Zeta电位负电位逐渐增加,矿物颗粒间静...

Dispersion Mechanism and First-Principles Analysis of Sodium Silicate in Collophanite Flotation System

The effect of sodium silicate dispersant on the dispersion behavior of fine collophanite in weak alkaline pulp was investigated by single mineral sedimentation test. The results show that when pH is 8.5, the dispersion effect of collophanite particles can be gradually increased with the increase of the sodium silicate concentration. When the sodium silicate concentration attains 800 mg/L, collophanite can sustain a stable dispersion state with the dispersion rate at 40%. The zeta potential analysis shows that with an increase in the sodium silicate concentration, collophanite is increasingly negatively-charged and the interparticle electrostatic repulsion is intensified. Based on the First-Principles, the adsorption configuration and adsorption energy of Si(OH)₄ on different terminal face of fluorapatite (001) surface were calculated using CASTEP module in Material Studio 6.0 software. The dispersion mechanism of sodium silicate in collophanite flotation system is revealed from the atomic aspect. The results show that H atoms in Si(OH)4 form hydrogen bonds with O atoms on the terminal faces of Ca, Ca-Ca and -[PO₄]-. The energies for the adsorption of Si(OH)₄ to three terminal faces are E_adCa=-35.43 kJ/mol, E_adCa-Ca=-55.63 kJ/mol and E_ad-[PO4]-=-13.56 kJ/mol, respectively. It is shown sodium silicate dispersant can be adsorbed on collophanite surface by physisorption and chemisorption.