... quality for various grade the Zinc Carbonate 57.5, 57, 56.5. Welcome your enquiries. Specialty supply ZINC CARBONATEThe Zinc Carbonate ... 57.5%, 57.0%, 56.5%, etc.Molecular Formula: ZnCO3•2Zn(OH)2•H2OMolecular Weight ... Qualified productMain content(Zn dry basis) % ≥ 57.5 57.0 56.5 Ignition loss %25.0-28.0 25.0-30 ...