Evaluate The Influence Of The Electrochemical Potential On The Surface Properties Of Pyrite Depression Case Study
Many researchers have conducted studies in order to evaluate the influence of the electrochemical potential on the surface properties of pyrite leading to its depression. For example, Hicyilmaz et al. measured contact angles of pyrite in the absence of collector in a potential range of -505 to +595 mV vs. SHE. and observed that with increasing the pulp potential from +400 to +595 mV vs. SHE, the contact angles decreased. Also in another study conducted by Guler et al., it was revealed that the floatability of pyrite in the collectorless conditions decreased with a significant increase in the electrochemical potential. The decrease in the contact angles and the floatability of pyrite with increasing the pulp potential was found to be due to
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One of the most important of these studies was conducted by Owusu et al. where they measured pH, the pulp potential (Eh) and the dissolved oxygen content of pyrite pulp after various aeration times of the pulp. Initially, the pulp was purged with air for 3 minutes and the dissolved oxygen content was then measured with time. They observed that the dissolved oxygen concentration of the pulp reduced from 5.5 to 0.06 mg/dm3 during 5 minutes. This showed that the oxygen dissolved in the pulp was nearly completely consumed by pyrite. However with increasing aeration time, it was observed that the residual dissolved oxygen content increased to 5.21 mg/dm3. On the other hand, it was also observed that with increasing the dissolved oxygen content of the pulp, the pulp pH decreased considerably and the pulp Eh changed from a reducing to more oxidizing value. These changes in pH and Eh of the pulp were found to be favorable for the pyrite oxidation and the oxygen consumption. Therefore, Owusu et al. concluded that with increasing aeration time, the formation of the iron oxy-hydroxide species and also coating the surface with these species increase. Then, however, because of the coverage of most of the pyrite surface by these species, a significant decrease in the surface reactivity with oxygen occurs. In other words, with further increase in aeration time, the pyrite surface is
One of the most important of these studies was conducted by Owusu et al. where they measured pH, the pulp potential (Eh) and the dissolved oxygen content of pyrite pulp after various aeration times of the pulp. Initially, the pulp was purged with air for 3 minutes and the dissolved oxygen content was then measured with time. They observed that the dissolved oxygen concentration of the pulp reduced from 5.5 to 0.06 mg/dm3 during 5 minutes. This showed that the oxygen dissolved in the pulp was nearly completely consumed by pyrite. However with increasing aeration time, it was observed that the residual dissolved oxygen content increased to 5.21 mg/dm3. On the other hand, it was also observed that with increasing the dissolved oxygen content of the pulp, the pulp pH decreased considerably and the pulp Eh changed from a reducing to more oxidizing value. These changes in pH and Eh of the pulp were found to be favorable for the pyrite oxidation and the oxygen consumption. Therefore, Owusu et al. concluded that with increasing aeration time, the formation of the iron oxy-hydroxide species and also coating the surface with these species increase. Then, however, because of the coverage of most of the pyrite surface by these species, a significant decrease in the surface reactivity with oxygen occurs. In other words, with further increase in aeration time, the pyrite surface is