Removal of Impurities from Indigenous (Chamlang) Coal by Using Froth Flotation Technology (original) (raw)
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Reduction of Sulfur and Ash from Tabas Coal by Froth Flotation
Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2007
Tabas mines in Iran have coal sources which are suitable for use in metallurgy industries as coking coal. But the high sulfur content of this coal imposes severe limitations on its utilization as the sulfur oxide gases evolved from the combustion of high sulfur coals result in acid rains and corrosion of equipments. In this work, attempts have been made to reduce sulfur from high sulfur coal of Tabas by froth flotation. Laboratory tests were carried out in order to investigate the influence of various collectors, frothers, pyrite depressants and their consumption dosages on ash and sulfur reduction of Tabas coal. The use of kerosene as a collector and pine oil as a frother has decreased ash and sulfur content of coal more than other collectors and frothers. Although use of sodium polyacrylic acid as a pyrite depressant improved the total recovery of coal concentrate but did not enhance the reduction of sulfur.
SSRN Electronic Journal
This study was carried out with one of the physiochemical techniques of coal sample beneficiation using froth flotation technique for upgrading the quality of Achibo-Sombo-Dabaso coal, southwestern Ethiopia. The investigations aimed to beneficiate high impure Ethiopian coal and to minimize its impurities present, so that it can replace the imported coal and the environmental pollution generated during combustion is reduced. The proximate and ultimate characterization studies show that the raw coal samples contain 11.81-20.27% moisture, 22.47-36.58% ash, 22.74-34.85% volatile matter, 23.85-38.31% fixed carbon, 1.22-1.44% nitrogen, 0.57-1.9% sulfur with 3243.59-5295.34 kcal/kg calorific value. Froth flotation experiments were carried out on the raw coal samples at varying parameters of collector dosages (0.0095 kg/ton, 0.0283 kg/ton, 0.0472 kg/ton, 0.0661 kg/ton and 0.085 kg/ton of diesel oil), frother dosages (0.0922 kg/ton, 0.1845 kg/ton, 0.2767 kg/ton, 0.3689 kg/ton and 0.4611 kg/ton of n-octanol) and particle size (500-250, 250-125, 125-63 μm). The experimental results for the treated coal samples are 8.12-14.02% moisture, 7.49-13.62% ash, 21.92-30.64% volatile matter, 44.47-55.87% fixed carbon, 0.52-0.92% nitrogen, 0.25-0.41% sulfur content with 5243.40-6531.46 kcal/kg of calorific value. The results of this study indicate that the treated coal samples are relative with high calorific value, fixed carbon and low ash content compared to the raw samples. The coal samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) to understand the flotation and size distribution of coal. Therefore, the froth flotation technique at parameters of collector dosages (0.0472 kg/ton of diesel oil), frother dosages (0.3689 kg/ton of n-octanol) and particle size (125-63 μm) is effective to increase the calorific value above 5000 kcal/kg and increment carbon content of Achibo-Sombo-Dabaso coal that suitable as an energy source in cement and steel industries.
Beneficiatipon of Chamalang Coal by Froath Floatation
Cleaning of Chamalang coal samples was carried out using froth flotation technique. The kerosene oil was used as a collector. Chamalang coal belongs to lignite to sub bituminous coal category. The constituents of the Chamalang coal sample such as inherent moisture, ash, volatile matter, fixed carbon, sulphur and gross calorific value were estimated on air dry basis and found to be 2.13%, 29.43%, 34.65%, 33.00%, 3.11% and 5482 kcal kg -1 , respectively. The froth flotation process was found to be suitable for ash reduction and enhancement of the volatile matter along with fixed carbon. The ash contents of the Chamalang coal samples were observed to be significantly removed (24.5%) whereas the volatile matter was found to be increased up to 25.8%. The effect of slurry ratio and pH was studied. The efficient cleaning of the Chamalang coal was obtained at pH 10 and using a slurry ratio of 25%.
Effective flotation of weathered coal using frother blend
2013
Froth flotation of weathered coal is a challenging task in a conventional flotation cell using commonly used collector and frother. Generally weathered coal shows the erratic flotation behaviour due to the surface oxidation as it makes the coal surface hydrophilic. When the surface gets oxidized, surface modifier is employed to float the clean coal. Frothers play significant role in stabilizing the mineralized bubble. It reduces the bubble size by reducing the interfacial tension at the air water interface. During this investigation, the flotation was carried out with two types of frothers namely; methyl isobutyl carbinol (MIBC), a weak frother and a strong polyglycol type. The Factorial design matrix was used for carrying out the experiments with the different ratio of frother blend, collector and promoter dosage. The high concentration of MIBC is found to be not effective for recovering the significant amount of carbon value as it causes less reduction of the interfacial tension a...
Influence of chemical parameters on selectivity and recovery of fine coal through flotation
International Journal of Mineral Processing, 2009
This paper summarizes how the chemical parameters (collector concentration, frother concentration and different mixed frothers) affect the selectivity, kinetics and size wise flotation performance. Three different mixed frothers have been taken for this study. Frother 'x' is composed of alcohol and ketone. Frother 'y' consists of alcohol and aldehyde group chemicals. Frother 'z' is a blended product of alcohol and polyglycol ether. Flotation performance of different mixed chemical systems is correlated with affinity of frothers with air-water interface. Blended frothing molecules of short chain alcohol and polyglycol ether have shown a dramatic impact on the surface activity and flotation performance in term of ash reduction and improvement in coal yield.
Recovery of Clean Coal for the use of Synthetic Fuels from Anthracite by Froth Flotation
The Korean Society of Mineral and Energy Resources Engineers
Coal generally contains numerous types of gangue minerals that produce different physical properties in the product. The aim of this study is to eliminate the impurities in coal by froth flotation to make it more suitable for use in synthetic fuels. In order to ensure optimum flotation conditions, the operational and physicochemical parameters of flotation need to be varied. According to the results, collector dosage and particle size had the most significant effect on the outcome. The results also suggest that the optimum conditions for the recovery of good quality clean coal are a particle size below 65 mesh (210 µm), using 1500 g/t kerosene as a collector; 1000 g/t sodium silicate as a depressant; and 100 g/t AF-65 as a frother. At this conditions, it is confirmed that clean coal can be recovered with a combustible recovery of over 85% and ash content below 12% by flotation.
The effect of reagents and reagent mixtures on froth flotation of coal fines
International Journal of Mineral Processing, 2003
Reagent usage and type of reagent are important factors in froth flotation. The recovery and purity of the final product obtained depend on various parameters such as the type and the amount of reagent, the nature and the particle size of solids, the adsorption of reagent on solid particle surface. The froth flotation tests of bituminous coal fines were carried out using only one of three non-ionic reagents; Triton x-100, Brij-35, methyl isobuthyl carbinol (MIBC) and sodium dodecyl sulfate (SDS), and the mixture of Triton x-100 or Brij-35 with MIBC in various ratios. The froth flotation performance was changed significantly according to addition of the reagent or reagent mixtures. The highest recoveries (>90%) were achieved in the presence of conventional reagents, MIBC or SDS. However, the ash rejection values were lower in the use of the same reagents. The ash rejection was considerably improved by using the mixture of reagents. A strong relationship was observed between the solid fraction in the concentrate and the type and amount of the reagent or the reagent mixture. The combustible solid recovery and the ash rejection strongly depend on the finer particle fraction in the feed.
Experimental Investigation on Safer Frother Option for Coal Flotation
Current Works in Mineral Processing
This work aimed to investigate a safer frother for coal flotation with achieving similar or better flotation performance, compared with the most common frother methyl isobutyl carbinol (MIBC) that caused some fire hazards in the past due to its low flash point (F.P. = 39 °C). Based on the higher flash points and low risk rating according to their safety data sheet, Dow Froth 250 (F.P. = 149 °C) and pine oil (F.P. = 78 °C) were selected to test against MIBC. Flotation tests were carried out at various frother dosages with/without diesel as a collector. Both Dow Froth 250 and pine oil had a good potential to be a safer alternative to MIBC in terms of coal grade and recovery. Pine oil was the most promising as a stand-alone reagent without a collector potentially making for a safer work environment with less chemical storage.
Morphology of flotation froth for enrichment of coal in saline water
E3S Web of Conferences, 2016
Gas bubbles have an important influence on the efficiency of flotation. The use of mine saline water in coal preparation plants affects the quality of froth. This paper shows the results of morphological analysis of froth generated in flotation enrichment process performed in technological waters with varying degrees of pulp salinity. The raw material model subjected to flotation tests was coal (type 33 in Polish classification). The appearance of froth was registered and evaluated by using a vision system with a special software. The aim of the study was to determine the size and number of air bubbles formed in the presence of inorganic electrolyte ions in the process water as well as their relationship with the efficiency of enrichment process.
Physicochemical Problems of Mineral Processing, 2021
An investigation was conducted to evaluate the effect of lip washing on coal flotation at Anglo American's Goedehoop South (GHS) fine coal plant in South Africa. In the test-work, performance of cells with lip washing system were compared with baseline cells without lip washing in terms of coal yield and coal quality. Yields observed with lip washing were significantly higher than those of baseline cells. Improvements of up to 15% were recorded. The product obtained at low flotation reagent dosages (1.30-1.45 kg/t) on lip wash cells had ~16.85% ash content against ~17.65% with baseline cells, suggesting that higher yields could be achieved at superior qualities to those achieved with baseline cells. At higher reagent dosages (1.60-1.75 kg/t), coal yields further improved but quality reduced on lip wash cells. Calorific Values (CV) of coal products obtained by lip washing and baseline flotation were similar. When different coal particle size fractions were floated separately, the yield increased as particle size increased from 75 to 300 µm and then decreased from 300 to 500 µm for both baseline and lip washing flotation. Lip washing caused a marked increase in the yield for finer particles (< 300 µm) with optimum size class of between 212-300 µm. In addition, a much bigger increase in the yield was achievable with lip washing of lower quality coal. The ash content after lip washing of poor-quality coal were also comparable to the ash content after lip washing of good quality coal.