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Abstract
At the rougher flotation circuit of the Miduk copper concentration plant (Kerman, Iran) five column cells (CISA) with the diameter of 4m and height of 12m using static mixer type (Microcel) spargers have been installed. Based on the initial design, columns should accept a feed rate of 625 t/h with 80% passing size of 90 μm and solids concentration of 28% and produce 88% of the plant concentrate (i.e., 22 t/h) containing 32% copper. Due to mechanical and processing problems this objective was never realized and these columns were remained out of operation from the commissioning time (2005). A new attempt with the aim of returning these cells into operation started in 2013. The results of an extensive study indicated that spargers plugging due to the entrance of small amount (2 kg) of coarse particles (up to 2.5 cm) because of usual problems at the plant environment was the main reason of columns non-functionality. With a change in the recycle pump inlet design to the column, which prevented the entrance of coarse particles to the spargers, the operation of the columns significantly improved. It was found that in order to have a stable operation of the columns at the rougher stage the feed rate for each column should be reduced from 125 (design) to 70 t/h. The air superficial rate had to be also reduced from 1.9 (design) to 0.6 cm/s. A period of 10 days of continuous operation showed that the carrying capacity was 0.23 (g/min/cm2) which was significantly lower than that of the design value (i.e., 0.58). The gas hold up was found to be lower than 10% beyond which columns started to move to the turbulent state indicated by “boiling” froth. The average life time of spargers was determined to be 20 days which considered to be very short. The average recovery and concentrate grade of these columns were found to be 68% and 32%, respectively. The high wear rates of spargers, unusually high level of maintenance and supervision needed and instability of the operation made the plant managers not to use column cells as the roughers.

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	All Years to Access Full-Text Export citations Lesson learned from using column flotation cells as roughers: The Miduk copper concentration plant case By A. Bahar, A. Arghavani, O. Farshid, M.R. Rozebehi, M. Mahdavi, S. Banisi Published in International Mineral Processing Congress (IMPC) at 2014 Direct link: http://kmpchemmat.ir/pii/42734 Abstract At the rougher flotation circuit of the Miduk copper concentration plant (Kerman, Iran) five column cells (CISA) with the diameter of 4m and height of 12m using static mixer type (Microcel) spargers have been installed. Based on the initial design, columns should accept a feed rate of 625 t/h with 80% passing size of 90 μm and solids concentration of 28% and produce 88% of the plant concentrate (i.e., 22 t/h) containing 32% copper. Due to mechanical and processing problems this objective was never realized and these columns were remained out of operation from the commissioning time (2005). A new attempt with the aim of returning these cells into operation started in 2013. The results of an extensive study indicated that spargers plugging due to the entrance of small amount (2 kg) of coarse particles (up to 2.5 cm) because of usual problems at the plant environment was the main reason of columns non-functionality. With a change in the recycle pump inlet design to the column, which prevented the entrance of coarse particles to the spargers, the operation of the columns significantly improved. It was found that in order to have a stable operation of the columns at the rougher stage the feed rate for each column should be reduced from 125 (design) to 70 t/h. The air superficial rate had to be also reduced from 1.9 (design) to 0.6 cm/s. A period of 10 days of continuous operation showed that the carrying capacity was 0.23 (g/min/cm2) which was significantly lower than that of the design value (i.e., 0.58). The gas hold up was found to be lower than 10% beyond which columns started to move to the turbulent state indicated by “boiling” froth. The average life time of spargers was determined to be 20 days which considered to be very short. The average recovery and concentrate grade of these columns were found to be 68% and 32%, respectively. The high wear rates of spargers, unusually high level of maintenance and supervision needed and instability of the operation made the plant managers not to use column cells as the roughers.