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Hunters Hill, Australia

Al Shakarji R.,James Cook University | He Y.,James Cook University | Gregory S.,Copper Refinery Ltd
Hydrometallurgy | Year: 2013

The effectiveness of various acid mist suppression techniques has been analysed in the present work. The two important factors that influenced the performance of a floating barrier were its coverage of the solution"s surface area and its height above the solution line. When comparing single layered floating barriers, spheres reduced acid mist the most due to their higher buoyancy and higher coverage of the solution surface. In general, barriers made of high density polyethylene were 3.4% more effective in reducing acid mist than thosemade of polypropylene due to their lower density which enabled them to be more buoyant in the solution and intercept acid mist more effectively. Acid mist was reduced noticeably with the addition of FC-1100 (a chemical reagent widely used to suppress acid mist) to the solution up to 30 ppm. Further addition of FC-1100 made much less difference in the suppression of acid mist. When FC-1100 was used in combination with floating barriers (such as spheres), the reduction in acid mist improved by an average of 29% in comparison to the use of FC-1100 alone. Crown Copyright © 2012 Published by Elsevier B.V. All rights reserved.


Shakarji R.A.,James Cook University | He Y.,James Cook University | Gregory S.,Copper Refinery Ltd
Hydrometallurgy | Year: 2011

Acid mist is generated during the final stage of hydrometallurgical metal refining processes including the electrowinning of copper. In this study, the effect of five process parameters and their interactions on the amount of acid mist generated is analysed quantitatively. The amount of acid mist generated was measured under 32 different operating conditions. It was found that solution's temperature and mist suppressant chemical FC-1100 had significant effect on the amount of acid mist generated. More than 90% of the variations in the acid mist generation can be explained by changes in these two parameters and their interaction. To a lesser extent, electrical current density and solution acidity also affected the total amount of acid mist generated. The anode's age and most of the 3, 4, and 5-way parameter interactions were found to have negligible influence on the amount of acid mist. Overall, acid mist was found to increase with temperature and current density. In contrast, increasing the viscosity of the solutions tends to decrease the amount of acid mist. © 2010 Elsevier B.V.


Al Shakarji R.,James Cook University | He Y.,James Cook University | Gregory S.,Copper Refinery Ltd
Hydrometallurgy | Year: 2011

Oxygen bubbles are formed on the anode in the copper electrowinning process. Burst of the bubbles produces acid mist in the tankhouse. While it is well acknowledged that the amount of acid mist is related to the size of the bubble, no systematic measurements have been made to quantify bubble size and its relationship with materials and process variables. This paper presents results of bubble size measurement under different operating conditions. For each of the operating conditions tested, bubbles were detected in a wide size distribution ranging from 20 μm to more than 400 μm in diameter. Statistical analyses on the measurement results showed that addition of FC-1100, a surfactant widely used in copper electrowinning to suppress acid mist, and solution temperature were the two most influential test parameters on the bubble size followed by the age of the anode. In contrast, current density and solution acidity had negligible effect. © 2011 Elsevier B.V. All rights reserved.


Al Shakarji R.,James Cook University | He Y.,James Cook University | Gregory S.,Copper Refinery Ltd
Hydrometallurgy | Year: 2012

The average bubble size and the amount of acid mist generated during copper electrowinning were measured under a variety of operating conditions. In the absence of surfactants, the amount of generated acid mist decreased as the average bubble size increased. In contrast, in the presence of FC-1100, a surfactant typically used to supress acid mist, acid mist showed little correlation with the average bubble size. The significant change in the bubble burst mechanism, due to the presence of surfactant molecules in the solution/air interface, is believed to be the reason for the suppression of the effect of bubble size on acid mist. © 2011 Elsevier B.V. All rights reserved.

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