Abstract:

Experimental research on the dissolution of aluminosilicate mineral has been carried out by putting quartz and plagioclasite grains in sodium acetic solutions(0.05 mol/L) with different sodium chloride concentrations.The contents of several mineral elements in experimental solutions have been measured.The result indicates that the content of SiO₂ in the solution with quartz grain reduces gradually with the increasing concentration of sodium chloride.It is therefore speculated that the dissolution of quartz reduce rapidly with the increase of salinity of formation water.In contrast,the dissolution of mineral elements in the solution with plagioclasite grain is different for metal ions with different electrovalences and shows various changing tendencies with the increa-sing concentration of sodium chloride in solution.The influences of various factors on dissolution rate,including inorganic ion activity in high-salinity brine and their common-ion effect,salt effect and chelating effect between anion and metal ion,have been studied and discussed.It is concluded that high concentration of sodium chloride is not favorable for the dissolution of silicon-oxygen tetrahedron and aluminium-oxygen tetrahedron.The commo-nion effect may slow down the preferential dissolution of alkali metal ions.While salt effect and chelating of inorganic anion Cl-may facilitate the dissolution of metal ions with high electrovalences.

Key words: common-ion effect, salt effect, chelating, dissolution of mineral, salinity, formation water