Abstract:While disposing of fine coal without use was cheaper and more permissible previously, recovering some of the fine coal changes the mass balance of wastes and makes co-disposal or integrated dumps possible. The present study aims to investigate the processing of fine lignite coal tailings with 59.08% ash content from Soma tailings ponds in Turkey using a Knelson concentrator and to identify in both numerical and experimental methods the fundamentals of the reason why the Knelson concentrator must be operated in… Show more
“…Özgen et al (2019) proposed the equations as a function of gravitational force, solid concentration, fluidization water pressure, and sample collection time, to estimated ash content and recovery of clean coal product [ 265 ]. Similarly, Sabah and Koltka (2014) developed the regression model in the function blow speed, fluidization water pressure, sample collection time, and solid concentration, to estimate ash content of clean coal products [ 266 ]. When centrifugal force is low (low bowl speed), KC will work like a hydrocyclone which means the separation did not take places upon particle density but particle size.…”
“…Özgen et al (2019) proposed the equations as a function of gravitational force, solid concentration, fluidization water pressure, and sample collection time, to estimated ash content and recovery of clean coal product [ 265 ]. Similarly, Sabah and Koltka (2014) developed the regression model in the function blow speed, fluidization water pressure, sample collection time, and solid concentration, to estimate ash content of clean coal products [ 266 ]. When centrifugal force is low (low bowl speed), KC will work like a hydrocyclone which means the separation did not take places upon particle density but particle size.…”
“…Centrifugal force makes the slurry fill the ribs from the bottom to the top. The feed moves upward as a thin film [54]. The lignite coal tailings (b 0.5 mm) from Soma region (Manisa/Turkey) were treated by a two-stage concentration scheme, namely pre-enrichment by hydrocyclone and a second enrichment by Knelson concentrator [54].…”
Section: Gravity Separationmentioning
confidence: 99%
“…The feed moves upward as a thin film [54]. The lignite coal tailings (b 0.5 mm) from Soma region (Manisa/Turkey) were treated by a two-stage concentration scheme, namely pre-enrichment by hydrocyclone and a second enrichment by Knelson concentrator [54]. The two-stage process produced a coal product containing 30.51% ash and 4259 kcal/kg base calorific value with a separation efficiency of 19.50% using Knelson concentrator.…”
“…Coal demineralization and desulfurization occur primarily by physical methods such as gravity separation and flotation at the mine sites. [10] However, gravity separation and flotation are not very effective in removing organic sulfur and finely dispersed inorganic sulfur and minerals that are commonly incorporated into the organic matter of coal. [11] As a result, it is a challenge to effectively reduce inorganic sulfur in addition to organic sulfur using only gravity separation or flotation.…”
Coal combustion greatly contributes to global emissions of toxic gases into the atmosphere, with sulfur emissions as one of the prominent pollutants in addition to carbon dioxide. Nevertheless, Botswana utilizes Morupule's sub‐bituminous coal with average sulfur and ash contents, as determined in this study being 1.9 and 24.4 % by weight with an average calorific value of 22 MJ Kg
−1
to generate electricity. We report an optimized extraction method for reducing total sulfur in Morupule coal from 1.9±0.2 to 0.43±0.02 wt.% at optimum conditions of ethanol/water (90/10, v/v %) at 129 °C (105 bars) in 10 minutes. A Box–Behnken experimental design was employed to select the optimal conditions of temperature (100–180 °C), water proportion in ethanol (10–90, v/v %) and extraction time (10–30 minutes), thus reducing the total sulfur under these mild conditions compared to conventional extraction. The optimized conditions were however not efficient in removing ash.
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