汞污染载金炭间接加热-N2吹扫脱汞研究
Study on removal of mercury in gold-loaded carbon under indirect heating and by nitrogen sweeping method
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摘要: 采用间接加热-N2吹扫法，对汞污染载金炭中汞的脱除进行试验研究。主要考察了吹扫方式、焙烧温度、N2流量和处理时间对汞脱除效果的影响。结果表明，采用床层内部吹扫方式有利于载金炭中汞的脱除；在550℃、N2 1.6 m3/h·kg、吹扫3 h条件下，能够将载金炭中汞含量由13.833 g/kg降低至0.002 g/kg，汞脱除率达到99.98%以上，而炭烧损率仅1.84%。另外，进行了2种二段法脱汞试验研究：高温蒸汞-N2吹扫法和空气吹扫-N2吹扫法。结果表明，与一段法相比，前者能够大大降低N2的消耗量；而后者没有明显优势，N2用量和能耗均未能明显降低。Abstract: This study investigated the removal of mercury in gold-loaded carbon under indirect heating and by nitrogen sweeping method. The effects of sweeping way, calcining temperature, nitrogen flow and sweeping time on the removal of mercury were explored. Results show that the sweeping way through carbon bed is favorable for the removal of mercury. Under the following conditions, i.e. 550℃, N2 1.6 m3/h·kg, the concentration of mercury in gold-loaded carbon can be decreased from 13.833 g/kg to 0.002 g/kg after being sweeped for 3 h, i.e. removal rate is more than 99.98%, burning loss of carbon is only 1.84%. Besides, two series of two-stage method for mercury removal was attempted, i.e. mercury retorted and further sweeped out by nitrogen both at high temperature, mercury sweeped out by air at lower temperature and by nitrogen at higher temperature. Results show that, in comparison with one-stage method, the former can significantly reduce the nitrogen amount used, while the latter does not display any advantage both in the nitrogen amount used and energy consumption.
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Key words:
- mercury and gold-loaded carbon /
- indirect heating /
- sweeping mercury /
- nitrogen /
- air /
- retort /
- one-stage method /
- two-stage method
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