CaCl_2对垃圾焚烧飞灰热处理特性的影响

The Effect of CaCl_2 on the Heat Treatment of MSWI Fly Ash

以华东某城市生活垃圾焚烧厂飞灰为原料,对飞灰中重金属进行了高温热处理研究,主要考察了CaCl2对重金属蒸发的影响,并对蒸发物化学形态及成分进行了分析.结果表明:CaCl2能有效促进飞灰中Pb和Cd的蒸发,当温度为1 050℃,CaCl2的添加比例为15%时,Cd的蒸发率由原灰的43.8%剧增到88.3%,而重金属Cu的蒸发率则随着CaCl2添加比例的增加有所降低;当CaCl2的添加比例为10%时,各重金属的蒸发率均随温度的升高而有不同程度的增加;对所收集的蒸发物进行成分及物相分析显示,蒸发物主要以NaCl和KCl为主,重金属Pb以双金属氯化物(KPb2Cl5)形式蒸发.

A heat treatment was carried out to test the effect of CaCl2 on fly ash from municipal solid waste incinerator （MSWI） in one city in East China, intending to know the efficacy of CaCl2 on volatilization of heavy metals and the chemical characteristic and compositions of the volatile matter. The results show that CaCl2 can effectively enhance the volatilization rate of Pb and Cd; when temperature was 1 050 ℃ and CaCl2 was 15%, the volatilization rate of Cd was 88.3%. The volatilization of heavy metals had a different degree of accretion along with increasing temperature, when CaCl2 was 10%. The analysis of compositions demonstrated that the collected volatile matter was mainly composed of chloride of NaCl and KCl, and Pb vaporized with the form of KPb2Cl5 .