脱气处理对微细白钨颗粒疏水聚团行为的影响

Influence of degassing on aggregation of ultra-fine scheelite particles

通过沉降试验、Zeta电位测定和显微镜观察试验,研究油酸钠体系下脱气处理对微细粒白钨矿疏水聚团行为的影响。研究结果表明:加热脱气能显著脱除水中溶解气核,且脱气后气体再次溶解速度缓慢,为后续试验稳定性和可靠性提供了保证;在脱气水中,微细白钨颗粒沉降行为与油酸钠浓度密切相关,当油酸钠浓度较低时,脱气处理后矿浆浊度增大,说明脱气处理促进白钨颗粒分散,当油酸钠浓度较高时,脱气水对应矿浆浊度较小;脱气水中白钨颗粒表面负电性增强,颗粒间静电排斥增强,不利于白钨颗粒间疏水聚团;脱气处理后,白钨颗粒间疏水聚团能力减弱;当油酸钠浓度较高时,未脱气矿浆溶液中固体颗粒由于气核的桥联作用可能形成链状或网状絮团结构,颗粒沉降时浮力增大,从而导致测定矿浆浊度反而较大。

The influence of degassing on aggregation of ultra-fine scheelite was studied through sedimentation test,Zeta potential measurement and microscopic observation.The results show that gas nuclei in water can be removed by heating,and the dissolution rate of gas is slow after degassing,which provides guarantee for the stability and reliability of experiments.The settling behavior of ultra-fine scheelite particles is closely related to the concentration of sodium oleate(NaOl)in the degassing water.When the concentration of NaOl is low,the turbidity of the mineral suspension increases when water is degassed,which suggests that the degassing promotes the dispersion of the scheelite particles,while the turbidity of the degassing aqueous dispersion is low when the NaOl concentration is high.The surface of scheelite particles is more negatively charged in the degassing water,thus enhancing the electrostatic repulsion between the particles,which is not conducive to the aggregation.The ability of aggregation of particles is reduced in the degassing water.In the case of high NaOl concentration,solid particles in the non-degassing slurry may form aggregates with chain or network structure due to the bridging effect of the gas nuclei,and therefore the buoyancy of aggregates increases sharply,resulting in the high turbidity in the measurements.