摘要
采用化学热力学平衡分析方法,应用造纸污泥实测数据预测了其焚烧中重金属(Ni、Mn、Zn和Cu)的迁移和转化规律.研究结果表明,考虑矿物质存且在低温条件下,造纸污泥焚烧中重金属Ni和Zn易与Fe2O3结合形成稳定的固体化合物,从而抑制了Ni和Zn的挥发性,而对Mn和Cu没有影响.焚烧温度为400—1800K范围内有矿物质存在条件下,Mn未出现其气体产物,而其他三种金属在高温条件下则以其气态单质或气态氧化物挥发进入大气环境.焚烧过程中只有小部分气态CuCl生成,未见其它气态金属氯化物;在焚烧温度为400—1800K条件下未发现金属硫化物或者硫酸盐生成,表明在有矿物质存在条件下S对金属的挥发性影响很小.在未考虑矿物质存在条件下,S在低温条件下易与重金属结合形成金属硫酸盐固体从而拟制了金属的挥发;随着温度的升高,Cl和重金属易形成金属氯化物气体,促进了金属的挥发特性,并且Cl对Cu的挥发影响较大,其次为Zn和Mn,影响较小的金属是Ni.从而根据污泥在不同焚烧温度下不同的产物形态进行重金属的污染控制.
Thermodynamic equilibrium calculations were performed to reveal the distributions of the heavy metals such as Ni,Mn,Zn and Cu during incineration of sewage sludge from paper mill.Actual paper mill sludge compositions and combustion conditions were utilized in all simulations.The results showed that Ni and Zn were easy to form stable solid compounds with Fe2O3,but the Fe2O3 compounds had no effect on the Mn and Cu distribution,which restrained the volatility of the metal Ni and Zn during incineration under conditions for the existence of minerals at low temperature.At high temperature,the heavy metal Mn did not produce its gas compounds during incineration,while the other three kinds of metals（Zn,Cu and Ni）formed their elementary gas or their metal-oxide gas compounds,which may enter the atmosphere environment with high risk.There was only a small part of the CuCl gas generated,and no other gaseous metal chlorides appeared in the incineration process.At 400—1800K,metal sulfides or sulfates were not produced,indicating that S had little effect on the volatile of metals with the existence of minerals.Without considering the existence of minerals,the S was easy to form solid metal sulfate with heavy metals,which held up the volatility of metals at low temperature.As the temperature increases,the Cl was easy to form metal chloride gases,which promoted the volatilization of metals.The chloride had the greatest impact on the volatilization of Cu,followed by Zn and Mn,less impact on the metal Ni.The control of heavy metals can be realized according to different kinds of metal products at different incineration temperature.
出处
《应用基础与工程科学学报》
EI
CSCD
北大核心
2012年第2期200-209,共10页
Journal of Basic Science and Engineering
基金
广东高校优秀青年创新人才培养项目(LYM11059)
广东省部产学研结合项目(2011B090400161
2011B090400144)
关键词
造纸污泥
焚烧
重金属
形态
热力学分析
paper mill sewage sludge
incineration
heavy metal
speciation
thermodynamic analysis
