Study On The Mechanism Of Inner Mongolia Shengli 6# Lignite Reverse Flotation Based On Surface Analysis

For a long period of time,the main fossil energy used in China is coal.With the depletion of high quality coal resources due to continuous mining,and the high reserves of low rank coal represented by lignite,the development and utilization of low rank coal has become a spotlight.In terms of resource utilization,the vast majority of lignite is used for electricity generation,which not only causes waste of resources,but also serious environmental pollution.Therefore,it is of great significance to actively promote the improvement of lignite quality and push up the clean use of lignite to save energy and protect the environment.In this paper,a new flotation method is proposed for Shengli 6# lignite and the study of the flotation mechanism of lignite is based on surface analysis.The main research contents and conclusions of the paper are as follows.Through industrial analysis,particle size analysis,morphological observation,contact angle measurement,and infrared spectroscopy analysis,the Shengli 6# lignite was analyzed,and discovered its strong hydrophilicity was due to its loose structure and high content of oxygen-containing functional groups,which introduced the application of the inverse flotation method;using the Zeta potential analyzer,I found that the absolute value of the zeta potential value of lignite was higher than that of quartz;through mineral composition analysis,we determined that the main impurity minerals of Shengli lignite were quartz.The critical micelle concentration of pyridine ionic liquids(CCM and DPC)was measured by capillary ascent method and surface tension meter,and the optimum pH of 7 for flotation of Shengli lignite was investigated by Zeta potential analyzer,which provided guidance for the subsequent flotation test and mechanism study.The study analyzed the structure of lignite and quartz,and introduced the hydration film and the formation principle of hydration film in process of flotation.Only in the way of thinning and destroying the hydration film,the effective contact between mineral particles and air bubbles can be achieved,and the flotation efficiency can be improved.In the meanwhile,the Shimadzu SPM-8100 FM used in this research was introduced specifically,which provides a new method of subsequent research in the field of mineral interface.The hydration film of lignite in water and n-dodecane was measured with SPM,and it was found that there was not obvious hydration film because lignite is a hydrophobic mineral;the hydration film of mica,which is a silica mineral,was measured in water,saturated potassium chloride solution,and CCM solution.The thickness of the hydration film which closest to the surface of mica was found to be about 0.2 nm in the water,while there was no obvious delamination in the CCM solution,which confirmed that CCM can effectively destroy the quartz hydration film,promote its contact with air bubbles and improve flotation efficiency.Then,FTIR was used to investigate the mechanism of CCM reverse flotation.By comparing the types of functional groups and the contents of quartz and those of quartz treated by chlorohexadecyl monohydropyridine,it was found that CCM absorbed quartz by electrostatic adsorption.What's more,this adsorption on the surface of quartz obscured oxygen-containing functional groups such as hydroxyl groups and extended the longchain alkyl end outward,which improved the hydrophobicity of quartz and promoted the reverse flotation process.And this study provided a theoretical basis for the application of ionic liquid in reverse flotation of ignite.Before the flotation test,various methods of test were explored,and finally reverse flotation was used for the quality improvement of Shengli 6# lignite creatively.With the pH=7,the effects of flotation process,regents' type,regents' concentration and inhibitor concentration on the results of the flotation tests were investigated,and it was found that the CCM zero-adjustment reverse flotation method with inhibitor failed to significantly reduce the ash content of coal concentrate,but increased the yield of lowash coal concentrate by 4.5 times and improved the flotation perfection index by 8 times,which greatly improved the flotation efficiency.After that,XRF and XRD tests were applied to compare and analyze the elemental content and vein mineral content of raw coal and fine tail coal,and EPMA was applied to observe the adsorption of CCM on the surface of quartz and lignite to evaluate the effect of the reverse flotation test.The paper has 38 pictures,7 tables,and 96 references.