EVALUATION OF CRYSTAL GROWTH INHIBITORS TO REDUCE ENCAPSULATION OF
GOLD IN LEACH SLURRIES
Rolf Andreas Lautena*, Guy Kluckb
b
*
a
Pionera, Hjalmar Wesselsvei 6, 1701 Sarpsborg, Norway
Pionera, Grand Avenue 100, Rothschild, Wisconsin, 54474 USA
Corresponding author: Tel +47 69118182 e-mail: rolf.andreas.lauten@pionera.com
ABSTRACT
Formation of scales may have important detrimental effects in many mineral processing application. A
well-known problem is the need for more frequent maintenance to remove scale from processing
equipment. Another challenge may relate to encapsulation of valuable minerals in precipitating scale.
In this work we explore the ability of different types of crystal growth inhibitors to prevent or lower the
degree of scale precipitation. In many situations pregnant leach solutions contains substantial
concentrations of calcium, magnesium, sulfate and carbonate in addition to dissolved valuable elements,
i.e. gold, copper, zinc. Together with non-dissolved gangue minerals some slurries may also contain
particulate gold, copper etc. During normal processing of the pregnant leach solution it may be exposed to
temperature gradients etc. promoting precipitation of various scales. Valuable minerals may become
entrapped in this precipitates and thus become inaccessible to the lixiviant. Use of a crystal growth
inhibitor may lower the degree of encapsulation of valuable elements.
Using simple model systems, supersaturated with respect to simple salts prone to form scale, the ability of
different crystal growth inhibitors to prevent precipitation of scale is explored. The concentrations of salt
constituents remaining in the pregnant leach solution after precipitation is compared to the theoretical
solubility of the relevant salts.
KEYWORDS
Leach, scaling, crystal growth modifiers, gold