Extraction kinetics of the alkali / alkaline earth metal in Zhundong coal with crown ether

Crown ether,as supramolecular compound,has highly selective complexation with alkali metal / alkaline earth metal ions. The crown ether is used in the field of coal chemical industry,to provide a new method for the study of the influence of single alkali / alkaline earth metal elements in coal on combustion,pyrolysis and gasification. The influence of different diluents,different crown ethers,extraction time,the concentration of crown ether,and extraction tempera- ture are examined. The results show that the diluent polarity is bigger,the extraction effect of crown ether is better. Dif- ferent kinds of crown ethers but with same aperture,have different complexation ability to the same alkali / alkaline earth metal ions due to different substituents in crown ether ring. Using chloroform as the diluent and dicyclohexyl 18- crown-6 as the extraction agent benefits the selection and extraction of non Na ions in the washing solution of Zhundo- ng coal. Improving the concentration of crown ether in organic phase can effectively enhance the extraction rate,but the separation coefficient does not increase with the concentration. Increasing the temperature is not conducive to the ex- traction reaction as it is an exothermic reaction.