【摘要】 主要研究以As、Cd、Cr为代表的痕量重金属在煤加热过程中的释放机理,因其挥发性将直接影响其对大气的排放量。试验表明,痕量元素的释放不仅与元素的物理化学性质有关,而且与元素在煤中的浓度和赋予的形态及燃烧工况等因素有关。As主要以硫化物形态存在,而且其熔点和沸点较低,故As最易挥发;而Cr主要以无机物形态存在,熔点和沸点又高,故最难挥发;而Cd介于二者之间,故挥发性As>Cd>Cr。试验证明随着温度升高,各元素的挥发率也逐渐升高,而且As Cd>Cr。更多还原

【Abstract】 With As, Cd and Cr serving as representative elements the release mechanism of trace heavy metals was mainly studied during the heating process of coal. The study is of great significance, because the volatility of these elements will directly affect their emission to the atmosphere. Tests have shown that the release of trace elements is related not only to their physical and chemical properties, but also to such factors as their concentration in coal as well as their acquired morphology and combustion conditions, etc. The element As mainly exists in the form of a sulfide and has a relatively low fusion and boiling point, thus exhibiting the greatest tendency to volatilize. On the other hand, Cr mainly assumes the form of an inorganic matter with a high fusion and boiling point, thus making it the most difficult to volatilize. The element Cd occupies a middle position between the above-cited two elements, resulting in a volatility expressed as As>Cd>Cr. Tests have proved that with a rise in temperature the volatility of these elements also gradually increase, and AsCd>Cr.更多还原