Pluronic F-68在萤石和石英表面的吸附特性及分散作用研究

Study on Adsorption Characteristics and Dispersion of Pluronic F-68 on the Surface of Fluorite and Quartz

Pluronic(普朗尼克)是一类非离子型双亲三嵌段共聚物,分子结构为PEO_(n)-PPO_(n)-PEO_(n),能够在矿物表面形成多种吸附构型,依靠空间位阻作用调控颗粒间的分散聚团行为,在解决矿物颗粒罩盖、异相凝聚方面具有较高的研究价值。以Pluronic F-68为研究对象,通过沉降试验考察其在细粒石英与萤石异相凝聚体系中的分散作用效果,利用吸附量测试和接触角测试分析了Pluronic F-68在萤石和石英表面的吸附特性与分散机理,并通过分子动力学模拟研究其吸附模型。结果表明:①矿浆pH=7时,Pluronic F-68能够实现细粒石英和萤石颗粒间的稳定分散;②Pluronic F-68在萤石和石英表面均形成了薄饼型单层吸附,PEO链段朝内,PPO链段朝外,依靠空间位阻效应,在显著提高矿浆分散稳定性的同时也增大了矿物表面疏水性;③分子动力学模拟结果验证了Pluronic F-68在萤石和石英表面的吸附构型,说明其在矿物表面的吸附具有一定的稳定性。试验结果为解决其他矿物异相凝聚体系提供了有益的借鉴。

Pluronic is a non-ionic amphiphilic triblock copolymer with a molecular structure of PEO_(n)-PPO_(n)-PEO_(n),which can regulate the dispersion and agglomeration behavior between particles using steric repulsion by forming vary adsorption configurations on the surface of minerals.It has high research value in solving mineral particles covering and heterogeneous agglomeration.Pluronic F-68 was introduced in this paper.The dispersion effect of Pluronic F-68 on the heterogeneous aggregation system of fine-grained quartz and fluorite was and investigated through sedimentation tests.The adsorption characteristics and dispersion mechanism of Pluronic F-68 on the surface of fluorite and quartz were analyzed by adsorption capacity test and contact angle test.In addition,the adsorption model was studied by molecular dynamics simulation.The research results show that:①When the pulp pH=7,fine-grained quartz and fluorite particles can stable dispersed with the addition of Pluronic F-68;②The pancake monolayer adsorption model of Pluronic F-68 on the both fluorite and quartz surface provide a steric hindrance which significantly improves the dispersion stability of the slurry,meanwhile the configuration of Pluronic F-68 with the PEO chain segment facing inward and the PPO segment facing outwards increases the hydrophobicity of the mineral surface;③The molecular dynamics simulation results verify the adsorption configurationof Pluronic F-68 on the surface of fluorite and quartz.The stable adsorption layer on the mineral surface further reveals the dispersant mechanism of this type agent,which provides a useful reference to solve other mineral heterogeneous coagulation systems using the nonionic amphiphilic triblock copolymer.