1、1 英文翻译原文Optimization of a Multi Gravity Separator to produce clean coal from Turkish lignite fine coal tailingsSelcuk Ozgen, Ozkan Malkoc, Ceyda Dogancik, Eyup Sabah, Filiz Oruc SapciA B S T R A C TIn this study, the beneficiation of two lignite tailings by Multi Gravity Separator (MGS) was investig
2、ated. The tailings samples from the Tunbilek/Ktahya and Soma/Manisa regions have ash contents of 66.21% and 52.65%, respectively. Significant operational parameters of MGS such as solid ratio, drum speed, tilt angle, shaking amplitude, wash water rate, and feed rate were varied. Empirical equations
3、for recovery and ash content were derived by a least squares method using Minitab 15. The equations, which are second- order response functions, were expressed as functions of the six operating parameters of MGS. The results showed that it is possible to produce a coal concentrate containing 22.83%
4、ash with a recovery of 49.32% from Tunbilek coal tailings, and a coal concentrate containing 22.89% ash with a recovery of 60.01% from Soma coal tailings.1. INTRODUCTIONCoal washing plants in Turkey use gravity separation to beneficiate coal particles larger than 500 lm, and discharge the fine fract
5、ion as tailings. In most coal washeries, around 20% of totalrun-of-mine coal is found to be less than 500 lm. The increased use of highly mechanized mining methodologies to enhance the productivity is the major cause for the generation of large uantitiesof coal fines 1. This situation not only cause
6、s economical loss, but coal areas also encounter serious environmental issues. In the past, beneficiation of fine coal tailings used the most commercially viable concentration processes such as jigs, densemedium cyclones, spirals, haking tables, and flotation, either individually or in combination 2
7、4. However, the processing of finecoal fraction is relatively difficult due to high processing cost, low process recovery, and high moisture content of the product. Recently, a new gravity based processor, Multi Gravity eparator(MGS), have appeared on the market with an operating principle which see
8、ms to be very promising for processing of fine particles 5. A detailed description of the MGS is given elsewhere 6,7. MGS may be visualized as a cylindrical version of a conventional shaking table 1,810. Briefly, the principal of MGS concentrating particles is based on the combined effects of centri
9、fugal acceleration and forces acting on a conventional table. This device was developed for selective separation of fine and ultra-fine particles mostly based on the differences in their densities. The use of centrifugal forces in a MGS enhances the relative settling velocity differential between pa
10、rticles different in size and density 1,11. In addition, shearing force created by shaking motion of the drum enhances the particle separation process 12. The early applications of the unit for concentrating heavy minerals like tin, tungsten, tantalum, chromites, and celestite have been reported els
11、ewhere 5,9,1220. Recently, most of the studies have focused on its use in processing of fine coal 1,7,10,2126. In this study, the applicability of MGS to recover two different fine coal tailings has been investigated, and the results from thisstudy have been used to create an empirical equation of r
12、ecovery and ash content for each coal tailings. Furthermore, it aims optimization of six operational variables for a MGS (pulp solid ratio, drum speed, tilt angle, shaking amplitude, wash water rate, feed rate), which are expected to be important in coal upgrading. Therefore the use of regression an
13、alysis with a mathematical software package, already successfully applied in beneficiation test and it is well suited to the main and interaction effects of the variables on cleancoal using a MGS. 2. MATERIALS AND METHODS2.1. MaterialsTwo lignite coal tailings obtained from Tunbilek Coal Preparation
14、 Plant of G.L.I of Turkish Coal Enterprises (Ktahya-Turkey) and Soma Dereky Coal Preparation Plant of Aegean Lignite Enterprises (Manisa-Turkey) were used in this study. The samples were taken from slurry waste with standard of TS ISO 5667-10 27.2.2. Methods2.2.1. Characterization testsA number of q
15、ualitative and quantitative analysis techniques were used to characterize the coal tailings. The chemical composition of the tailings was defined by X-ray fluorescence (XRF). The mineral composition of the tailings was determined by X-ray diffraction (XRD) method using a Rigaku-Giger Flex analyzer.
16、The particle size distribution of the tailings was obtained using a Retsch AS200 Sieve Shaker and Fritsch-Analysette 22 Particle Size Analyzer. The specific gravity of the tailings was determined by Quantachrome Ultrapycnometer 1000. The ash and sulfur contents of the tailings were determined according to ISO 1171 and ISO 351, respectively. In addition, the calorific value was determined based on ISO 1928. Following the haracteri
