鳞片石墨在水中的聚团行为

鳞片石墨在水中表现出强疏水性,易形成疏水聚团,其聚团行为影响分选过程的选择性和加工利用过程的分散性。通过对鳞片石墨粉体颗粒的润湿接触角、润湿热、ξ电位的测量及真空浮选实验,研究了鳞片石墨在水中的聚团行为。结果表明:鳞片石墨粉体颗粒的接触角接近90°,疏水性强;不同粒级的鳞片石墨被水润湿呈现出放热和吸热两个过程,且不能自发进行;接触角越大,Zeta电位越小,颗粒越易聚团。石墨颗粒在水面上以大鳞片为中心形成片状聚结,随着颗粒浓度的增多,相互叠加形成远大于颗粒尺度的聚团。鳞片石墨在水中的聚团行为符合扩展的DLVO理论,颗粒间的疏水作用力是聚团形成的根本原因。

Study on reunite behaviour for flake gaphite in water

Flake graphite shows strong hydrophobicity,and tends to form agglomerate in water,thus affecting the selectivity of the selection process and the dispersion in utilization process.The study on the characters of the agglomeration of flake graphite powders in water by measurements of the contact angle,the heat of wetting,Zeta potential and the experiment of vacuum flotation shows that flake graphite powder,with the contact angle of close to 90°,exhibits strong hydrophobicity.Flake graphite of different grain sizes,subject to the wetting process,show two processes： the exothermic process and endothermic process,which fail to occur spontaneously.The increasing contact angle of flake graphite yields decreasing Zeta potential,allowing flake graphite particles to agglomerate more easily.The flake graphite particles agglomerating with the core of big flake graphite particle,due to increasing graphite particle concentration,overlap to aggregation considerably bigger than a single particle.The agglomeration behaviors of flake graphite particles in water can be explained by the extended DLVO theory and the hydrophobic interaction between the particles is the fundamental reason for the formation of agglomerates.