Abstract:Abstract:A flotation bank is a serial arrangement of cells. How to optimally operate a bank remains a challenge. This article reviews three reported strategies: air profiling, mass-pull (froth velocity) profiling and Peak Air Recovery (PAR) profiling. These are all ways of manipulating the recovery profile down a bank, which may be the property being exploited. Mathematical analysis has shown that a flat cell-by-cell recovery profile maximizes the separation of two floatable minerals for a given target bank re… Show more
“…The process is repeated down the bank until the particles are rejected into the overall tailings of the circuit. Due to its serial structure, the manner in which individual cells are operated to achieve optimal performance is not straightforward [1]. In addition, the flotation performance is not measured cell-by-cell but only for the overall bank, which limits the application of serial staged-optimization techniques, such as dynamic programming [2][3][4].…”
This article describes the impact of restricting the air intake in industrial 250 m3 WEMCO flotation cells at Los Pelambres concentrator. The influence of this air restriction on the hydrodynamic and metallurgical performance of this type of machine was evaluated. The experiments were conducted in single flotation cells and in entire rougher banks. In all cases, the gas holdup was measured to estimate the effectiveness of the obstruction system to decrease the air concentration. In single cells, axial profiles for solid percentage and particle size were evaluated. In addition, a mass balance was conducted to assess the copper recovery and concentrate features. In individual cells, the air restriction led to a decrease in the gas holdup. However, this slight change was enough to obtain a more stable froth zone and a better solids suspension. The latter was observed as a higher P80 below the pulp-froth interface, a less diluted pulp at this level, a slightly higher Cu recovery, and a coarser concentrate product. A mineralogical analysis of the concentrate sample also showed the presence of coarser liberated Cu-sulfide particles. The results in single cells suggested an improvement in the recovery of coarse particles by a more intense solids suspension. The air intake was also restricted in 3 rougher banks to assess the impact of the air obstruction on the overall performance of the respective circuit. Eleven out of fourteen cells were operated with air restriction, which led to a significant recovery improvement of 0.9%-1.6% (absolute) with a 95% confidence level. Size-by-size mass balances were also conducted for the rougher circuits, which proved that the recovery improvements were justified by the simultaneous increase in the recovery of coarse and fine particles. Thus, a restriction of the air intake showed that the decrease in the gas holdup (and in the bubble surface area flux) was compensated by a better solids suspension and a higher turbulence in the impeller. The former promotes the recovery of coarse particles, whereas the latter improves the interaction between bubbles and fine particles. Further developments are being made to implement a regulatory control strategy to control the air intake in self-aspirated flotation cells, and to use this approach for optimizing industrial flotation banks.
“…The process is repeated down the bank until the particles are rejected into the overall tailings of the circuit. Due to its serial structure, the manner in which individual cells are operated to achieve optimal performance is not straightforward [1]. In addition, the flotation performance is not measured cell-by-cell but only for the overall bank, which limits the application of serial staged-optimization techniques, such as dynamic programming [2][3][4].…”
This article describes the impact of restricting the air intake in industrial 250 m3 WEMCO flotation cells at Los Pelambres concentrator. The influence of this air restriction on the hydrodynamic and metallurgical performance of this type of machine was evaluated. The experiments were conducted in single flotation cells and in entire rougher banks. In all cases, the gas holdup was measured to estimate the effectiveness of the obstruction system to decrease the air concentration. In single cells, axial profiles for solid percentage and particle size were evaluated. In addition, a mass balance was conducted to assess the copper recovery and concentrate features. In individual cells, the air restriction led to a decrease in the gas holdup. However, this slight change was enough to obtain a more stable froth zone and a better solids suspension. The latter was observed as a higher P80 below the pulp-froth interface, a less diluted pulp at this level, a slightly higher Cu recovery, and a coarser concentrate product. A mineralogical analysis of the concentrate sample also showed the presence of coarser liberated Cu-sulfide particles. The results in single cells suggested an improvement in the recovery of coarse particles by a more intense solids suspension. The air intake was also restricted in 3 rougher banks to assess the impact of the air obstruction on the overall performance of the respective circuit. Eleven out of fourteen cells were operated with air restriction, which led to a significant recovery improvement of 0.9%-1.6% (absolute) with a 95% confidence level. Size-by-size mass balances were also conducted for the rougher circuits, which proved that the recovery improvements were justified by the simultaneous increase in the recovery of coarse and fine particles. Thus, a restriction of the air intake showed that the decrease in the gas holdup (and in the bubble surface area flux) was compensated by a better solids suspension and a higher turbulence in the impeller. The former promotes the recovery of coarse particles, whereas the latter improves the interaction between bubbles and fine particles. Further developments are being made to implement a regulatory control strategy to control the air intake in self-aspirated flotation cells, and to use this approach for optimizing industrial flotation banks.
“…Flotation is one of the most widely used techniques to separate valuable minerals from gangue minerals in the mineral processing, because of its ability to treat low-grade and complex raw materials in the fine particle size ranges [3][4][5][6][7]. Froth flotation takes place in the presence of three different phases, including solid (particles), liquid (water) and gas (air bubbles).…”
The dominant challenge of current copper beneficiation plants is the low recoverability of oxide copper-bearing minerals associated with sulfide type ones. Furthermore, applying commonly used conventional methodologies does not allow the interactional effects of critical parameters in the flotation processes to be investigated, which is mostly overlooked in the literature. To tackle this issue, the present paper aimed at characterizing the behavior of five key effective factors and their interactions in a sulfidized copper ore. In this context, dosage of collector (sodium di-ethydithiophosphate, 60–100 g/t), depressant (sodium silicate, 80–120 g/t) and frother (methyl isobutyl carbinol (MIBC), 6–10 g/t), pulp pH (7–11) and agitation rate (900–1300 rpm) were examined and statistically analyzed using response surface methodology. Flotation experiments were conducted in a Denver type agitated flotation cell at the rougher stage. The experimental results showed that increasing the pH (from 8 to 10) at low agitation rate (1000 rpm) enhanced the recovery from 80.36% to 85.22%, while at high agitation rate (1200 rpm), a slight declination occurred in the recovery. Meanwhile, increasing the collector dosage at a lower frother value (7 g/t), caused a reduction of about 4.44% in copper recovery owing to the interactions between factors, whereas at a higher frother level (9 g/t), the recovery was almost unchanged. The optimization process was also performed using the goal function approach, and maximum copper recovery of 92.75% was obtained using ~70 g/t collector, 110 g/t depressant, 7 g/t frother, pulp pH of 10 and 1000 rpm agitation rate.
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