CHEMICALLY PRECIPITATED CHALK Russian patent published in 2000 - IPC

FIELD: inorganic materials. SUBSTANCE: chemically precipitated chalk containing calcium carbonate, magnesium carbonate, iron and aluminium oxides, silicon dioxide and water-soluble compounds has components in the following ratio, wt.-%: sum of iron and aluminium oxides, 0.4-0.7; silicon dioxide, 0.014, not above; manganese, 0.01, not above; copper, 0.0005, not above; water-soluble compounds, 0.50-1.5; sum of calcium carbonate and magnesium carbonate, the balance. Chalk bulk density is 0.25-0.4 g/cm³ and sum of iron and aluminium oxides has iron (as measured for iron oxide) in the amount 0.1-0.3%. Chalk has calcium, magnesium, aluminium, iron, copper, manganese chlorides and nitrates. Invention can be used in food, perfume-cosmetic, medicinal, chemical and other branches of industry. EFFECT: enhanced whiteness and other quality properties of ready product. 3 cl