CaCO3 scale deposition from its sludge was studied on copper substrate. Ethylenediamminetetraacetic acid was used as chelating agent and tested for its influence on the deposition. The experiments were carried out at 60 and 100 degrees C and the effect of direct heating and indirect heating was studied. The samples were characterized by XRD, FTIR and SEM techniques. The data revealed that the complex forming nature of EDTA, the shape of the crystallite and area of contact are the key factors for the deposition of CaCO3 on metal surface. (C) 2016 Elsevier B.V. All rights reserved.