... in the tannery.3. Sepecification CompositionFeed GradeTec GradePurity, wt.%, min 98 .0 98.0Ca content, wt.%, min. 30.4 30.1Heavy metals (Pb ... ), wt.%,max. 0.001 --Water insoluble, wt.%, max. 0.2 -- Dry weight loss (%), wt.%, max. 0.5 0.5PH of 10% solution ...