Title
Main factors affecting the size of hydrogen and oxygen bubbles produced in the electroflotation process
Date Issued
01 January 2016
Access level
metadata only access
Resource Type
conference paper
Author(s)
Pontifical Catholic University of Rio de Janeiro
Publisher(s)
Canadian Institute of Mining, Metallurgy and Petroleum
Abstract
Understanding the limits of fine particle flotation is fundamental to achieving a significant and selective separation. Conventional flotation processes are not suitable to treat these particles because of their low collision efficiency. This problem can be overcome by decreasing the bubble size or by increasing the apparent particle size. However it is worth noting that the use of small bubbles or micro bubbles also involves some disadvantages such as their low momentum resulting in a slower process comparing with conventional flotation. Electroflotation is an attractive alternative for treating fine particles with small bubbles less than 100 µm, generated by the electrolysis of water. In this sense, this study assesses the effect of current density and pH on bubble size in a binary electroflotation cell. An increase in the bubble generation rate was reported with an increase in current density. In addition, at acid pH values, the size of oxygen bubbles increased and conversely decreased at basic pH values; this may be due to the electrostatic attraction between the oxygen bubbles and the anode resulting in a greater nucleation time. An opposite trend was observed with the hydrogen bubbles. These results are in agreement with their electrokinetic studies, which reported that at acid conditions the bubble surface may be positively charged for both the hydrogen and the oxygen bubbles. Finally the bubble size was slightly affected by the electrolyte concentration, resulting in smaller diameter bubbles at higher concentrations.
Volume
2016-September
Language
English
OCDE Knowledge area
Ingeniería eléctrica, Ingeniería electrónica
Subjects
Scopus EID
2-s2.0-85048338303
ISBN
9781926872292
Source
IMPC 2016 - 28th International Mineral Processing Congress
Sponsor(s)
The authors acknowledge CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico), VALE, CETEM (Centre for Mineral Technology), CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) and FAPERJ (Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro) for their financial support.
Sources of information:
Directorio de Producción Científica
Scopus