Experimental study on pre-treatment of high-mineralization mine drainage using gangue of different particle sizes

YAO Qiangling; HUANG Gang; XU Qiang; ZHU Liu; GUO Haotian

Abstract：Using the pore structure and adsorption characteristics of gangue to pre-purify high-mineralization mine drainage provides an economical and effective technical approach for the efficient utilization of mine drainage in ecologically fragile mining areas.This paper simulates the infiltration and migration process of mine water in under-ground rock strata through a self-made dynamic leaching experimental device,and studies the influences of different li-thologies and particle sizes of gangue on the pre-purification of high-mineralization mine drainage.XRD and XRF tests show that the main mineral components of mudstone siltstone and medium-coarse sandstone roof rock samples are quartz,kaolinite,muscovite,and feldspar,with the content of clay mineral kaolinite exceeding 20%.The layered struc-ture of kaolinite can adsorb more ions from mine drainage,purifying mine drainage resources.Dynamic leaching test results indicate that under the dynamic adsorption effect of gangue,the pH of high-mineralization mine drainage tends towards weak alkalinity,and the TDS value and Ca2+concentration both decrease;the larger the gangue particle size,the smaller the decrease in TDS value and Ca2+concentration in the mine drainage sample,indicating poorer adsorption effect.Compared to mudstone siltstone,medium-coarse sandstone has a stronger pre-purification effect on mine drainage solution ions.After mine drainage leaching,numerous pores and fractures on the surface of the rock samples undergo physical adsorption under hydrochemical action,forming secondary fractures.A large number of easily soluble components dissolve into the leachate,increasing the amount of debris on the gangue surface.The in-creased pore surface area and volume accelerate the dissolution of rock sample minerals,promoting the adsorption of mine drainage ions by the gangue.