硫化物对垃圾掺烧污泥焚烧飞灰高温过程中重金属挥发的影响  

Effects of Sulphur Compounds on the Volatile Characteristics of Heavy Metals in Fly Ash from the MSW and Sewage Sludge Co-combustion Plant During the Disposal Process with Higher Temperature

作　　者：刘敬勇[1] 孙水裕[1] 

机构地区：[1]广东工业大学环境科学与工程学院,广州510006

出　　处：《环境科学》2012年第11期3990-3998,共9页Environmental Science

基　　金：广东省高校优秀青年创新人才培养项目(LYM11059);广东省科技计划项目(2012B05030023);广东省部产学研结合项目(2011B090400161;2011B090400144)

摘　　要：对某垃圾掺烧污泥焚烧厂焚烧飞灰进行了采样,在对飞灰进行热重(TG-DTG)分析基础上,重点研究了飞灰水洗前后及其添加不同硫化物(S、NaS、Na2SO3、Na2SO4)经高温处置过程中重金属(Cu、Zn、Pb、Cd)的挥发特性.结果表明,飞灰中重金属Zn、Pb含量较高,Ni的含量较低,而Cd含量达到29.4 mg·kg-1.飞灰水洗后Pb、Cu、Zn的含量均比原灰中高,而Cd的含量降低.飞灰TG-DTG曲线在579～732℃、949～1 200℃这2个温度范围失重率较大,拐点温度分别为690℃和1 154℃.焚烧飞灰中Pb表现出易挥发的特性,其挥发率超过80%,而Cu挥发性较小,其挥发率<30%.飞灰水洗后,重金属的挥发率有显著的降低,其中重金属的挥发性大小依次为:Zn>Pb>Cd>Cu.飞灰热处置过程中预先加入Na2SO3、Na2SO4后,重金属(Cu、Pb、Zn、Cd)挥发率降低明显,而S的加入只能降低Zn的挥发率;Na2S加入后Cd、Zn挥发率下降.水洗飞灰添加Na2S后可降低4种重金属的挥发率,S及Na2SO3的加入分别降低了Cu和Zn的挥发率;4种硫化物的加入都可降低Cd的挥发率.研究结果为飞灰最大限度无害化处理及资源化回收利用提供理论依据.Fly ash sample was collected from a MSW co-combustion with sewage sludge plant and the volatilization of heavy metals Pb,Cd,Cu and Zn was investigated before and after the water washing of fly ash,meanwhile,the influence of adding different sulphur compounds（S,NaS,Na2SO3,Na2SO4） on the volatilization of heavy metals was studied.The results showed that the contents of Zn,Pb and Mn were high,the Ni content was low and the Cd content reached 29.4 mg·kg^-1.The contents of Pb,Cu,Zn increased,while that of Cd reduced in the fly ash after water washing.TG-DTG curves of fly ash showed highest weight loss in ranges of 579-732℃ and 949-1 200℃,with 690℃ and 1 154℃ as the inflection point temperatures.The volatilization of different heavy metals showed great difference in the volatilization rate,following the order of PbCdZnCu,in which the volatilization rate of Pb was more than 80% and that of Cu was less than 30%.After water washing,the volatilization of different heavy metals showed great difference in the volatilization rate,with the order of ZnPbCdCu,in which the volatilization rate of Zn was more than 20%.With the pre-treatment of adding Na2SO3 and Na2SO4,the evaporation rates of heavy metals（Cu,Pb,Zn,Cd） were significantly decreased.After adding S,the evaporation rate of Zn was reduced,whereas the addition of Na2S reduced the evaporation rates of Cd and Zn.The evaporation rates of the four heavy metals were all reduced after adding Na2S in the washed fly ash.The evaporation rates of Cu and Zn were reduced with addition of S and Na2SO3 and the evaporation rate of Cd was reduced by adding the four sulfides.The results can provide a basis for the harmless disposal and maximized resource utilization and recycling of fly ash.

关 键 词：飞灰 焚烧 重金属 挥发率 硫化物 

分 类 号：X705[环境科学与工程—环境工程]