CHEMICAL TREATMENT FIGURE 1
Calcium Carbonate Scale Formation and Inhibition in the Presence of Zinc Ions
fected by Zn2+
when added alone at
concentrations of 2, 5, and 10 ppm under this test condition. The changes in alka- linity values in these samples were similar to samples without Zn2+ PQJQ\QWV MNÅKQMVKa WN BV2+
tributed to two factors. First, Zn2+ strong enough to inhibit CaCO3
tion with a high scaling tendency and for an extended period. Second, Zn2+
– and ZhCl4 2–
. The lack of in- could be at- is not
forma- com-
plexes with chloride ions in the high- KPTWZQLM WQTÅMTL JZQVM \W NWZU KPTWZQLM rich ion pairs such as ZnCl3
, Effect of zinc ions on CaCO3 FIGURE 2 scale formation.
and these ion pairs are not effective as a CaCO3
inhibitor. However, Zn2+ showed
a noticeable impact on the performance of three inhibitors tested. Tables 1 and 2 summarize the calcu-
lated inhibition percentage for tests at two different ICs and two test durations. All four sets of tests showed similar trends, that Zn2+
enhanced the performance of
Chemical B and C but reduced the inhibi- \QWV MNÅKQMVKa WN +PMUQKIT ) .WZ M`IU- ple, in the 3-h tests with 1 ppm of scale inhibitor, the inhibition percentage de- creased from 62 to 25% for Chemical A, but increased from 43 to 62% for Chemi- cal B and from 58 to 64% for Chemical C when 2 ppm of Zn2+
was added (Table 1). Such effects became more obvious in
Effect of zinc ions on the performance of Chemical A. In dynamic tube blocking tests, the
JTIVS [KITQVO \QUM _I[ LM\MZUQVML ÅZ[\ using a test brine without any additives.