Calcium Carbonate

Calcium carbonate is the most widely traded calcium salt in the nutraceutical trade, and the reason is arithmetic: at a molecular weight of 100.09 with a single calcium atom, it delivers 40.0% elemental calcium. No other commonly used calcium source comes close, which means a 500 mg elemental calcium dose can be built into a tablet that a consumer will actually swallow. It is practically insoluble in water (around 14 mg/L at 25 °C) and dissolves with effervescence in dilute hydrochloric, acetic or nitric acid — behaviour that governs both its disintegration profile in tablets and its handling in wet processes. Thovek supplies precipitated (light and heavy) grades and granular directly compressible grades, milled to the mesh specification the buyer's press or blender requires. Food and pharmacopoeia grades are held against the JECFA/FCC purity criteria — assay not less than 98.0% CaCO3 on the dried basis, loss on drying not more than 2.0% at 200 °C, acid-insoluble matter not more than 0.2%, free alkali not more than 0.05%, and magnesium and alkali salts not more than 1.0%. Lead is controlled to not more than 3 mg/kg and arsenic to not more than 3 mg/kg. USP, EP/BP and IP grades are supplied against the respective monograph where the buyer's dossier requires it. Every lot ships with a Certificate of Analysis covering assay, elemental calcium, loss on drying, acid-insoluble matter, heavy metals and microbiology, together with an MSDS and the origin and manufacturing declarations needed for customs clearance. Material moves in 25 kg lined sacks on export pallets. Buyers should note the classification point: refined and precipitated calcium carbonate is a carbonate of HS heading 2836 and is entered at ITC-HS 28365000, not under the 2106 food-preparation codes that finished supplements use.