IMPROVED IN-VITRO METHODS FOR DETERMINING LIMESTONE AND OYSTER SHELL SOLUBILITY

Experiments were conducted to determine the effect of changing the aci d volume, acid normality, and incubation time on in vitro solubility v alues of various test calcium samples. A 200 mL volume of 0.2 N HCl so lution combined with 2.0 g sample size and 10 min incubation time at 4 2 degrees C produced a limestone solubility range of 20.96% to 78.15% for the samples used. This procedure produced a model for determining limestone or oyster shell weight loss (WL): WL = 1.809 + 0.601 x ln(pH change) (adjusted R-2 = .961); solubility percentage was calculated a s WL x 100/initial sample weight. This in vitro solubility procedure p roduced a higher limestone solubility range for the test samples; indi cating its ability to better distinguish among different quality limes tone and oyster shell sources. An in vitro assay using less than 2 g o f samples produced a higher standard error of the mean when large-part icle limestone and oyster shell samples were tested.