What is maximum allowable content of clay in lime-stone, for example?
Lime-stone is wide-spread sedimentary rock. It consists mainly of calcite CaCo3. It is observed as either rest of lime-stone mussels and skeletons of various organisms or as small crystal grains. It contains often significant content of rock-forming mineral – double calcium and magnesium carbonate CaMg[CO3]2 – dolomite, sandy or clayey particles. Lime-stones are classified as dolomite, sandy and clayey (marl) ones.Large content of bound clays is permittable but content of free-state clay may not be greater that 2%.