CALCIUM RELEASE FROM 11 MINERALS OF FINE-SAND SIZE BY DILUTE SULFURIC ACID

Abstract

Equal volumes of 11 freshly-ground minerals of fine-sand size were weathered with dilute H2SO4 during 18 successive weekly periods. For most minerals an “early-weathered" and a "semi-weathered" stage were recognized in curves for calcium release, pH and conductivity. The semi-weathered stage provides a more correct basis for comparing calcium release among minerals than the early-weathered stage. Semi-weathered minerals released calcium in order of decreasing rates as follows: calcite, dolomite, apatite, bytownite, diopside, grossularite, labradorite, augite, hornblende, oligoclase and albite. Release of calcium is related to calcium content and structure of minerals.