Development of a carrying-capacity model for column froth flotation (original) (raw)
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A parametric study of froth stability and its effect on column flotation of fine particles
International Journal of Mineral Processing, 2000
Laboratory flotation tests have been conducted to examine the effect of froth stability on the column flotation of finely pulverized coal. It has been demonstrated that the upgrading of coal in a flotation column can be significantly improved when froth stability is properly controlled through Ž. Ž. the manipulation of appropriate variables such as gas flow rate V , wash water flow rate V , g w froth height, wash water addition point, and feed solid concentration. Increases in wash water flow rate and gas flow rate promoted froth stability, resulting in higher combustible recovery, but possibly higher ash recovery as well. The optimum rates were determined to be 2 and 0.3 cmrs for V and V , respectively. The specific influence of wash water flow rate on water recovery was g w found to be closely related to how the frother dosage was maintained. Coal particles could stabilize or destabilize the froth, depending on their size and concentration in the cell. Those in y100 mesh fraction destabilized froth at lower concentrations and stabilized it at higher concentrations while micronized particles always showed froth-breaking power. The froth profiles of solid content and ash content were established at varying wash water flow rates and wash water addition points, from which it was concluded that froth cleaning occurred primarily at the pulp-froth interface and drainage above the wash water addition point.
Modified column flotation of mineral particles
International Journal of Mineral Processing, 1996
This work summarizes flotation results obtained in a modified column which selectively separates drained particles from the froth zone and uses a secondary wash water system between the feed and the froth zone. Flotation results on gold, copper, lead-zinc and fluorite ores are reported. The combination of separating the froth drop-back material as a "third-product" and secondary washing improved, the concentrate grades when compared to the conventional column cell. When the modified column was used for "rougher flash" flotation or as a cleaner of copper ores; clean copper concentrates analyzing 33-40% copper were obtained (33% recovery). Flotation recovery of gold from tailings was as much as 15%, with concentrate grades higher than 160 g/t. As a cleaning stage in lead-zinc ore flotation, recoveries of both sulfides were of the order of 92-94% with grades up to 80-82%, as compared to 70% in the "conventional" column. With the fluorite ore, recoveries of the order of 94%, were achieved with high selectivity (about 96% CaF,) at high flotation rates. The performance of the modified column is better than the conventional column due to improved mass transfer conditions. Finally, data on the influence of some cell design parameters are reported and the potential practical applications of this type of cell are discussed.
Selective detachment process in column flotation froth
Minerals Engineering, 2006
The selectivity in flotation columns involving the separation of particles of varying degrees of floatability is based on differential flotation rates in the collection zone, reflux action between the froth and collection zones, and differential detachment rates in the froth zone. Using well-known theoretical models describing the separation process and experimental data, froth zone and overall flotation recovery values were quantified for particles in an anthracite coal that have a wide range of floatability potential. For highly floatable particles, froth recovery had a very minimal impact on overall recovery while the recovery of weakly floatable material was decreased substantially by reductions in froth recovery values. In addition, under carrying-capacity limiting conditions, selectivity was enhanced by the preferential detachment of the weakly floatable material. Based on this concept, highly floatable material was added directly into the froth zone when treating the anthracite coal. The enriched froth phase reduced the product ash content of the anthracite product by five absolute percentage points while maintaining a constant recovery value.
An analysis of effect of particle size on batch flotation of coal
Physicochemical Problems of Mineral Processing, 2013
This paper presents the analysis of the batch flotation with regard to the size of the floated particles with coal as an example. Empirical studies were conducted on samples of bituminous coal from the Jankowice coal mine (33 type in Polish classification). Experimental includes fractional flotation of coal samples with various particle size, the float and sink analysis of flotation products and determination the ash content in each flotation and densimetric fractions. The evaluation of flotational upgrade was based on the partition curve and value of heterogeneity index (standard deviation) with the division into concentrate and tailings as a measure of flotation efficiency. From the partition curve, partition size, which is assumed in flotation as the maximum size of floatable particles under the given physicochemical conditions, was calculated. On the basis of float and sink analyses, it was found that floated particles are particles with hydrophobic properties corresponding to t...
Minerals Engineering, 2007
The concentrate mass flow rate of solids of a flotation column was modeled based on geometrical principles and considering complete air recovery to the concentrate and bursting of a fraction of the bubbles that reach the top of froth. For the first consideration, the results show that concentrate mass flow rate of solids experimentally measured, is smaller than that estimated with the geometrical model. For the second consideration, bursting of a 0.45 fraction of the bubbles reaching the top of froth gave improved results (average relative error obtained under these circumstances is about 20%).
Kinetic modelling of flotation column and Jameson cell in coal
Physicochemical Problems of Mineral Processing
Physical enrichment technologies can be used worldwide in various coal washing plants to enrich up to 500 μm particle size. Conversely, coals smaller than this are discarded as waste, causing storage and environmental issues. In this regard, studies on coal below 500 μm in Turkey have recently acquired attraction. The Jameson flotation cell and flotation column, which have many uses worldwide but are not used throughout the plant in Turkey, were used to investigate the separation possibilities of coals below 500 µm. In the study, the flotation column and Jameson cell performances for three different particle sizes (-500+300,-300+212 and-212+106 μm) were compared. For the first time, both machines operated in a negative bias condition. In addition, the flotation kinetics of the machines were modelled with some critical operating parameters. Models illustrating the main and multiple effects of the parameters were developed using the data derived from the experimental results, and the models were statistically significant at the 95% confidence level. In the experiments performed with both flotation machines, the flotation rate increases with the decrease in particle size in general. According to the results, the velocity increase in the Jameson cell was 0.0050-0.0075 min-1 compared to the flotation column in the experiments performed in the size range of-500+300 µm, and the flotation rate constant increased approximately twice. In the size range of-212+106 µm, the difference became larger, and the flotation rate of the Jameson cell increased up to six times with a difference of 0.0450-0.0500 min-1 .
Flotation Performance Analysis on Coal Washery Rejects
2020
Coal washery rejected coals and coal slurries have better options in froth flotation as a separation process. In this study, coal slurry received from Sudamdih coal washery, Jharkhand, India, examined for cleaning through fixed cell flotation. The Petrography study of the feed sample showed the presence of vitrinite, semi vitrinite and liptinite and inertinite as major minerals. General full factorial statistical design package (Minitab V17) was used to develop the regression models for the responses like froth height, froth density, recovery and ash content of clean coal. Results showed that experimental responses like froth height, froth density, recovery and ash content were found to be more sensitive to the frother dosage. The coefficient of correlation (R2) values between the experimental and the predicted values of the flotation responses was found to be >0.98 for all the models. Further, flotation tests were conducted for varying pulp density and its effect on recovery, fr...
The effects of frother and collector distribution on flotation performance
Minerals Engineering, 2005
The distribution of frother reporting to the concentrate along a bank of cells and the adsorption of collector to valuable particles are important as they determine the froth structure and flotation performance. An understanding of this is required in order to formulate better reagent addition strategies. Techniques to measure the frother concentration in samples taken from industrial flotation circuits, including dynamic surface tension measurements, have proven inconclusive due to the low concentrations used and the effects of hydrophobic particles. In this study, a method of measuring the concentration of non-adsorbed reagents on a laboratory scale has been developed. Batch flotation experiments were carried out on an industrial sulphide ore. The adsorption of the collector (SIBX) and frother (Dowfroth 200) to the solid particles was determined by measuring the concentration remaining in filtered liquid samples taken from the concentrate and tails. Analysis was carried out using UV spectrometry and TOC analysis. It was found that 20% of the frother is lost in the presence of the SIBX and that after 2 min, 63% of the SIBX had adsorbed to particles. The results also showed that an increase in the initial concentration of SIBX, and an increase in the conditioning time yielded a higher concentrate grade.
International Journal of Mineral Processing, 2007
The entrainment of hydrophilic gangue particles in flotation is related to the amount of water reporting to the froth. It is well established that the amount of water reported to the froth is controlled by frother concentration. As it is shown in this paper, in the flotation systems in which emulsified oily collector is also used (e.g. coal flotation), solids recovery strongly depends on the collector dosages as also does the water recovery. While the tests carried out at low (1000 g/t) and high (8000 g/t) oil dosages show different effects of frother additions on water transfer rates to the froth, all the experimental points when water transfer rates are plotted versus solids transfer rates to the froth converge on one single curve. This suggests that the effect of both the frother and collector on water transfer rates is first of all determined by the transfer of solids to the froth, and thus by the effect of these two agents on the solids transfer to froth.