• AWWA WQTC60664

AWWA WQTC60664

Inhibition of CaCO3 Scale Deposition by Trace Concentrations of Some Common Ions

American Water Works Association , 11/15/2004

Publisher: AWWA

File Format: PDF

$12.00$24.00


Trace concentrations of metal ion impurities, such as Fe2+, Fe3+ and Mg2+, which are commonly encountered in water, can retard significantly the precipitation of CaCO3. In view of the paucity of viable techniques for overcoming scale deposition difficulties, it is important to examine options for CaCO3 scale control by trace amounts of inhibiting metal ions. The literature cites Zn 2+ ions as being particularly effective in suppressing CaCO3 scale deposition. This paper reviews phenomena induced by the presence of ion impurities. Literature data relating to the retardation of CaCO3 nucleation and crystal growth processes by adsorption of impurities on crystal growth sites are analyzed and correlated. The effect of the presence of Zn2+ ions on CaCO3 scale deposition from hard waters having a Langelier saturation index of 1.0 to 1.5 was measured in two experimental heating systems. A marked scale suppression effect was obtained with as little as 1 to 1.5 PPM Zn2+ ion, added to the water either by dosing a Zn2+ solution or by the release of Zn2+ ions through contact with a redox Zn-Cu alloy medium such as a granular bed of KDF-55®. Includes references, tables, figures.

More AWWA Standards PDF

AWWA WQTC58806

AWWA WQTC58806

$12.00 $24.00

AWWA ACE58114

AWWA ACE58114

$12.00 $24.00

AWWA MTC57574

AWWA MTC57574

$12.00 $24.00

AWWA WQTC58807

AWWA WQTC58807

$12.00 $24.00