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首页> 外文期刊>Energy & fuels >Gaseous Mercury Release during Steam Curing of Aerated Concretes That Contain Fly Ash and Activated Carbon Sorbent
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Gaseous Mercury Release during Steam Curing of Aerated Concretes That Contain Fly Ash and Activated Carbon Sorbent

机译：含粉煤灰和活性炭吸附剂的加气混凝土在蒸汽养护过程中释放的气态汞

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Gaseous mercury released from aerated concrete during both presteam curing at 25 ℃ and steam curing at 80 ℃ was measured in controlled laboratory experiments. Mercury release originated from two major components in the concrete mixture: (1) class F coal fly ash and (2) a mixture of the fly ash and powdered activated carbon onto which elemental mercury was adsorbed. Mercury emitted during each curing cycle was collected on iodated carbon traps in a purge-and-trap arrangement and subsequently measured by cold-vapor atomic fluorescence spectrometry. Through 3 h of presteam curing, the release of mercury from the freshly prepared mixture was less than 0.03 ng/kg of concrete. Releases of total mercury over the 21 h steam curing process ranged from 0.4 to 5.8 ng of mercury/kg of concrete and depended upon mercury concentrations in the concrete. The steam-cured concrete had a higher mercury release rate (ng kg~(-1) h~(-1)) compared to air-cured concrete containing fly ash, but the shorter curing interval resulted in less total release of mercury from the steam-cured concrete. The mercury flux from exposed concrete surfaces to mercury-free air ranged from 0.77 to 11.1 ng m~(-2) h~(-1), which was similar to mercury fluxes for natural soils to ambient air of 4.2 ng m~(-2) h~(-1) reported by others. Less than 0.022% of the total quantity of mercury present from all mercury sources in the concrete was released during the curing process, and therefore, nearly all of the mercury was retained in the concrete.
机译：在受控实验室实验中测量了在25℃预蒸汽固化和80℃蒸汽固化期间从充气混凝土中释放出的气态汞。汞的释放源于混凝土混合物中的两个主要成分：（1）F级粉煤灰和（2）粉煤灰与粉状活性炭的混合物，元素汞被吸附在该混合物上。在每个固化周期中排放的汞以吹扫捕集的方式收集在碘化碳捕集阱上，然后通过冷蒸气原子荧光光谱法进行测量。经过3小时的预蒸汽养护，新配制的混合物中的汞释放量小于0.03 ng / kg混凝土。在21小时的蒸汽养护过程中，总汞的释放量为0.4至5.8 ng汞/ kg混凝土，具体取决于混凝土中的汞浓度。与含有粉煤灰的空气养护混凝土相比，蒸汽养护混凝土具有更高的汞释放率（ng kg〜（-1）h〜（-1）），但是硫化间隔时间越短，从汞中释放的汞总量越少。蒸养混凝土。从裸露的混凝土表面到无汞空气的汞通量为0.77至11.1 ng m〜（-2）h〜（-1），这与自然土壤向环境空气中的汞通量为4.2 ng m〜（-）类似。 2）h〜（-1）被他人报道。在固化过程中，从混凝土中所有汞源中释放的汞总量不到总汞量的0.022％，因此几乎所有汞都保留在混凝土中。

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