垃圾焚烧飞灰中不同粒径的毒性特性

Toxicity characteristics of different particle sizes of fly ash from municipal solid waste incinerators

对广州市某垃圾焚烧发电厂的焚烧飞灰进行粒径分级毒性分析研究。主要研究了粒径在35～1 000μm范围内的飞灰的腐蚀性和短期浸出毒性,包括Cr、Cd、Mg、Pb、Mn、Fe、Cu、Zn、Ni、Co等重金属,SO24-,Cl-,NO3--N和NO2--N,同时也研究了飞灰的物质组成和矿物特性。研究结果表明,所有粒径飞灰的浸出液pH值在12.3～12.5之间,属于有腐蚀性的危险废物,重金属Mg、Pb、Zn的浸出浓度最高,分别为168.78、53.94和86.40 mg/L。飞灰浸出液和含量最高分别达到8.87g/L和1.38 g/L,同时浸出液中测出一定量的硝态氮和亚硝态氮,证明飞灰吸附了垃圾焚烧过程中产生的氮氧化物气体。另外,研究得出飞灰的基本组成元素为Ca、Si、Cl、K、Na、S、Al、Mg和Fe,而重金属则以Zn、Pb、Mn、Cu、Cr等为主。矿物相主要为含硅和钙的化合物及NaCl和KCl等氯化物。

Size charge fractionation for the characterization investigation of municipal solid waste incinerator fly ash in Guangzhou was investigated. Causticity and short-term leaching toxicity of fly ash with various particle sizes in the range of 35 to 1 000 μm were examined. The heavy metals Cr, Cd, Mg, Pb, Mn, Fe, Cu, Zn, Ni, Co, sulphate, chloridion, soluble salts nitrate nitrogen and nitrite nitrogen, as well as the chemical composition and mineralogy property were detected. The results showed that leachating pH values of all particle sizes fly ashes were in the range of 12.3 to 12.5. The leaching concentrations of heavy metals Mg, Pb and Zn had the highest concentrations 168.78, 53.94 and 86.40 mg/L, respectively. The highest leaching concentrations of Cl^- and SO4^2＋- were 8.87 g/L and 1.38 g/L, respectively. In addition, the results that nitrate nitrogen and nitrite nitrogen were detected in fly ash, demon- strated that fly ash could adsorb nitrogen oxide gases during incineration process. Furthermore, the basic elements of fly ash were Ca, Si, C1, K, Na, S, A1, Mg and Fe, the main heavy metals were Zn, Ph, Mn, Cu and Cr. The main mineral phases were silicon and calcium compounds, NaCl, KCl chlorides etc.