黔西南高砷煤热解过程中微量元素释放规律研究

采用高温箱式电阻炉对黔西南海子地区煤样进行热解,研究了在300~1200℃下慢速热解过程中,热解温度、元素赋存状态和灰分对微量元素释放规律的影响.结果表明,热解温度是影响煤失重和微量元素挥发的主要原因. As、Mo在900℃以上挥发较快; Pb热解前期挥发较快,450℃以上挥发缓慢;Sb随热解温度的升高缓慢增大.微量元素的挥发性还与赋存状态关系密切,有机态最为活泼;硫化物态和碳酸盐态在热解后期由于矿物的分解而逐步释放;硅酸盐态最稳定,基本残留在灰分中.灰分越高微量元素越不易挥发.

Volatility of trace elements during pyrolysis of high arsenic coal from southwestern Guizhou.

Pyrolysis experiments were carried out in a box resistance reactor at 300~1200℃ to evaluate the volatility of trace elements in the coal from southwestern Guizhou. The impact of pyrolysis temperature, mode of element occurrence and ash content of coal on trace elements release were investigated. Coal weight loss and trace element volatility were primarily affected by pyrolysis temperature. As and Mo showed an strong release when temperature was higher than 900℃. Pb showed a high volatility at the early stage of pyrolysis(< 450℃), and then a lower volatility when temperature was over 450℃. With the increase of pyrolysis temperature, the volatility of Sb increased gradually. The volatility of trace elements showed a close correlation with the mode of element occurrence. Trace element of organic phase was most labile, while trace element of sulphide phase and carbonate phase volatilized gradually at the late stage of pyrolysis owing to the decomposition of mineral. Silicate phase was most stable, and basically remained in the ash. A high ash content of coal usually corresponded to a low volatility of trace elements.