Acidification adjacent to an elemental sulfur stockpile: I. Mineral weathering

Abstract

The objective of this study was to examine the influence of extreme acidity on the changes and redistribution of major chemical and mineralogical components in soil along the side of a 25-year-old elemental sulfur block. Soil samples were analyzed for total content of Al, Fe, Ca, Mg, Na, K, and Ti; Sand and clay separates were analyzed by X-ray diffraction, and physical and chemical methods. Carbonate, Fe-containing primary minerals, chlorite, smectite, and plagioclase feldspars were either partially or completely dissolved in soil having pH values of about 2.1. Clay-sized mica and kaolinite were apparently not affected by the acidity. Calcium carbonate and Ca-feldspars dissolved in the presence of H2SO4 to form gypsum. Iron dissolved from minerals in the acidified surface layer was deposited primarily as oxyhydroxides at the interface of acidic and calcareous materials to form an indurated layer about 10-15 cm thick. -from Authors