Investigation of the leaching of the platinum group metal concentrate in hydrochloric acid solution by chlorine
Date
2016
Authors
Asamoah- Bekoe, Yaw
Journal Title
Journal ISSN
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Abstract
The dissolution of platinum-group metals (PGMs) requires a high chloride ion
concentration in an acidic solution and a suitable oxidant. At Impala Platinum Refinery,
the concentrate is leached in a hydrochloric acid solution using chlorine gas as the
oxidant. The goal of this leaching step is a total dissolution of the PGMs and gold. The
silver precipitates as silver chloride. The efficiency of this stage is crucial for the
performance of the precious metals refinery.
The aim of this project is to investigate the factors that influence the efficiency of the
PGM leaching operation and to model for the results obtained. In order to investigate
and evaluate the total dissolution of the PGt;~; in HClICl2 leach system, it is necessary
to establish the effective conditions for the dissolution of chlorine gas in hydrochloric
acid solution. The results showed that the solubility of chlorine gas increases with an
increase in the acid concentration and chlorine gas concentration but decreases as the
temperature increases. The HCI solution is almost saturated with chlorine after about
50 minutes. The chlorine mass' msfer coefficient is dependent on the temperature, the
stirrer speed, the concentration of the HCI solution and that of the chlorine.
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