Measurement of bubble size distribution in copper electrowinning process by image analysis
Al Shakarji, Reza, He, Yinghe, and Gregory, Simon (2010) Measurement of bubble size distribution in copper electrowinning process by image analysis. In: Proceedings of Copper 2010: Electrowinning and -refining (4), pp. 1237-1252. From: Copper 2010, 6 - 10 June 2010, Hamburg, Germany.
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During electrowinning of copper, oxidation reaction occurs at the surface of the lead anode and oxygen gas is liberated. The size and the burst mechanism of the oxygen bubbles are known to have significant effects on the generation of acid mist. However, little is known about the actual size and its distribution of the oxygen bubbles that are generated under typical operating conditions of a copper electrowinning tankhouse.
This paper presents a technique for the measurement of oxygen bubbles formed in a copper elec-trowinning process. Live images of the generated oxygen bubbles were captured by utilizing a high speed camera, super bright LEDs and a special viewing chamber. A MATLAB based software was developed to analyse the images and to determine the size of the bubbles.
The effect of electrical current density on the size of the oxygen bubbles was experimentally investigated. Results show that regardless of the current density applied, bubbles were found in various sizes ranging from 33 μm up to 278 μm. They also revealed that current density had negligible effect on bubble size distribution. The mean bubble diameter for all three different current densities was found to be between 65 and 68 μm.
Experimentally measured amount of acid mist was found to increase linearly with the increase of current density. Based on Faraday’s Law, the total volume oxygen generated at the anode is linearly related to the current density. Since the current density had negligible effect on the bubble size, it was postulated that the total number of bubbles generated at the anode was also linearly related to current density.
|Item Type:||Conference Item (Refereed Research Paper - E1)|
|Keywords:||electrowinning, bubble size measurement, image analysis, acid mist|
|Date Deposited:||05 May 2011 04:44|
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