细粒沉积物(岩)中重矿物提取方法的改进

随着近百年的重矿物研究,从沉积物中提取重矿物的实验方法已经形成了固定模式,然而这些传统方法都是对砂岩粗颗粒矿物研究经验的积累,并不适用于泥质含量高的细粒沉积物.根据溶胶稳定(DLVO)理论,悬浮于溶液中的微细颗粒会因分子间作用力的相互吸引絮凝成团,从而影响细粒沉积物中重矿物提取的效果.实验研究证明,影响重矿物提取的主要因素是微细矿物颗粒间的絮凝作用,而并非有机重液的黏度.如何克服微粒间的絮凝作用是提取泥岩和粉砂岩中重矿物的关键.实验对比分析表明,添加分散剂的超声波振动和自然沉降法可以在克服絮凝作用的前提下有效去除泥质成分,同时对粉砂级矿物进行精确的粒径分选;离心分离同样也可以克服微粒间的絮凝作用,在重液分离过程中使重矿物顺利从轻矿物中分离.以上3种方法的联合使用可以弥补传统的重矿物提取方法的不足,并显著提高泥岩、粉砂岩中重矿物的提取率.

Improving the Methods of Heavy Minerals Pretreatment and Minerals Separation in Mudstone and Siltstone

Heavy minerals in mudstone and siltstone are becoming more and more important and indispensable part of similar further study.How to remove the argillaceous composition from the muddy fine-grained sediments(rock) and fully collect the heavy minerals is the premise of studying the heavy minerals of fine-grained sediments(rock).From the Sol stability theory(DLVO) we know that the fine particles suspending in solution will flocculate to agglomerate by the attraction of intermolecular interactions.So how to overcome the flocculation between particles is the key point in handling mudstone and siltstone.By experimental and comparative analysis,we hold that ultrasonic vibration with dispersants can resolve flocculation and make particulates disperse in water.Natural sedimentation method with Stokes sedimentation principle can dislodge mud,and at the same time seperate the minerals in accurate size.Centrifugalization can also overcome the flocculation between particles so that heavy minerals can settle into the bottom of the heavy liquid.The above three methods are key steps of picking up heavy minerals from muddy sediment.Using them can make up the limitation of traditional experimental methods.