Effect of interfacial properties on mechanical stability of ash deposit

The paper presents a study on the cohesion of volcanic ash particles using surface free energy determination and zeta potential analyses.This is a subject of great interest in physical volcanology,as many researches on volcanic particle aggregation are frequently reported.In this case,special attention is paid to the role of structural or hydration forces between hydrophilic surfaces,which are a consequence of the electron-donor/electron-acceptor character of the interface.From this point of view,the results are potentially interesting as they could give valuable insights into this process.The results are presented in terms of the total energy of interaction between dispersed particles,computed from the extended DLVO theory.Contributions to the total free energy of interaction were determined from the zeta potential and surface free energy of ash,measured under different experimental conditions.Two samples of basaltic volcanic ash(black and white)with silica contents of 44% and 63% respectively are studied.The surface free energy and zeta potential were analysed for ashes immersed in different electrolytes(NaCl,CaCl,FeCl).The presence of electrolytes changes the surface properties of the solid materials.The analysis of total interaction energy between the ash particles in aqueous medium shows that soil cohesion strongly depends on ash surface properties,chemical nature,the adsorbed cation on the surface,and p H value.

SLon立环脉动高梯度磁选机在秘鲁铁矿的应用

SLon立环脉动高梯度磁选机具有富集比大、选矿效率高、适应性强、磁介质不易堵塞、设备作业率高的优点 ,近几年在国内的矿山已经大规模应用。SLon立环脉动高梯度磁选机于 2 0 0 4年出口到秘鲁 ,成功地应用于分选氧化矿 ,使矿区原来堆积的大量氧化矿得到充分利用 ,且有利于原生矿的进一步开采 ,从而缓解了采场的供矿矛盾 。