新疆高碱煤分选组分中碱性矿物赋存及差异演化研究  

Occurrence and transformation behavior of AAEMs in the flotation fraction of a typical Xinjiang coal

作　　者：林雄超[1] 杨远平[1] 徐荣声[1] 李首毅[1] 岳文菲 王永刚[1] 

机构地区：[1]中国矿业大学(北京)化学与环境工程学院,北京100083

出　　处：《燃料化学学报》2017年第2期157-164,共8页Journal of Fuel Chemistry and Technology

基　　金：国家自然科学基金(21406261);"十二五"国家科技支撑计划重点项目(2012BAA04B02)资助~~

摘　　要：以新疆五彩湾高碱煤为原料,通过有机重液浮选和理化分析及热力学模拟解析活性矿物质热演化特性。结果表明,五彩湾煤以密度在1.40-1.50 g/cm^3的组分为主(质量分数超过70%)。可溶性Na和K等主要存在于较低密度组分(-1.40 g/cm^3)中;在高密度(+1.50 g/cm^3)组分中发现了以硅铝酸盐形式存在的碱及碱土金属(AAEMs)。Ca主要以方解石形式存在,伴随高岭土和石英富集在高密度组分中。在低温(500℃)灰化时少量Na释放,大量可溶钠盐的残留导致各分选组分中Na的扩散量相差不大。在815℃热处理温度下,低密度组分中大部分Na挥发到气相中;高密度组分中的部分碱金属可被黏土(高岭土)和石英等矿物质捕获,抑制其释放。Fact Sage热力学模拟发现,温度低于550℃时Na盐仍稳定存在于灰中;温度高于550℃时Na盐开始挥发,同时部分Na向NaAlSiO_4转化;在约620℃时,Na盐消失,同时NaAlSiO_4的含量逐渐趋于稳定。SiO_2含量的差异显著影响含Na等矿物质的演变行为。在500-815℃,Ca以CaSO_4和硅铝酸钙的形式稳定存在,而M g则在不同形式的硅酸盐之间发生转变。The occurrence and thermal transformation behaviors of AAEMs（ alkali and alkaline earth metal species） in a typical Xinjiang coal（ Wucaiw an） were systematically investigated. The raw coal sample was primarily separated to four fractions based on different densities by float-sink experiments using organic heavy solutions. Subsequently,the BSE-EDX（ backscattered electron-energy dispersive X-ray detector） and XRD were employed to analyze the mineral matters in coal fractions. Moreover,the thermal transformation behaviors of minerals in coal were simulated using Fact Sage. The results show that the active minerals（ i.e.,AAEMs） in coal vary with the flotation density and exhibit quite different transformation characterizations. Samples with density of1.40-1.50 g/cm3 are the major fraction（ 70%） for Wucaiw an coal. The Na and K exist principally in the low er density（-1. 40 g/cm3） fraction; in contrast,the AAEMs are combined with the alumina-silicate in the high density（ ＋1.50 g/cm3） fraction. Additionally,Ca is mainly in the form of calcite; and kaolinite and quartz are enriched in the high density fraction. Less Na could release at low er heat treatment temperature（ 500 ℃）; thus the release amounts of Na in four fractions present less difference. The majority of Na is volatilized from the low density coal sample at 815 ℃; but for the high density coal samples the clay（ mainly kaolinite） and quartz could capture Na and restrain its release. According to the Fact Sage calculation,the Na Cl is found to be still stable in the coal ash at 550 ℃; it would start evaporate over 550 ℃ and generate NaAlSiO4. The Na Cl would vanish at620 ℃ and the NaAlSiO4 gradually becomes constant. Moreover,at the temperature range of 500-815 ℃,Ca is mainly in the form of CaSO4 and Ca-Si-Al,while Mg varies in several forms.

关 键 词：分选 赋存形态 演化差异 新疆煤 

分 类 号：TQ546[化学工程—煤化学工程]