Li Yanlong, Fang Zhenquan, Teng Wenchao, Shen Shengqiang, Li Rundong
Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, School of Energy and Power Engineering, Dalian University of Technology, Dalian 116024, China.
College of Energy and Environment, Shenyang Aerospace University, Key Laboratory of Clean Energy, (Liaoning Province), Shenyang 110136, China.
ACS Omega. 2020 Sep 17;5(38):24467-24476. doi: 10.1021/acsomega.0c02939. eCollection 2020 Sep 29.
Recycling the phosphorus in sludge by incineration has received great interest at home and abroad. However, heavy metals (HMs) is a restrictive factor for SS thermal treatment. In this study, a comprehensive evaluation method was adopted to evaluate the comprehensive control efficiency of HM emissions during two-step thermal treatment (incineration-calcination). The effects of temperature, calcination time, and additives (CaO and NaCl) on leaching rates, stabilized rates, and comprehensive control efficiency of HM emissions were investigated. Results showed that comprehensive control efficiency increased significantly with an increase of temperature because of the transformation of chemical speciation from a leachable to a more stable combined form. Additives Cao and NaCl promoted the volatilization of HMs and reduced the comprehensive control efficiency. The highest comprehensive control efficiency of HM emissions was 78% when the incineration temperature reached 950 °C. Furthermore, a comparison was made between leaching rates, stabilized rates, and a comprehensive evaluation method. The results were inconsistent when leaching rates and stabilized rates were adopted. In contrast, when the comprehensive evaluation method was used, the results were coordinated and unique. This work can provide a promising approach for the evaluation of control efficiency of HM emissions during the process of thermal treatment of sludge.
通过焚烧回收污泥中的磷在国内外已引起广泛关注。然而，重金属是污泥热处理的限制因素。本研究采用综合评价方法评估两步热处理（焚烧-煅烧）过程中重金属排放的综合控制效率。研究了温度、煅烧时间和添加剂（CaO和NaCl）对重金属浸出率、稳定率和排放综合控制效率的影响。结果表明，由于化学形态从可浸出形式转变为更稳定的结合形式，综合控制效率随温度升高而显著提高。添加剂CaO和NaCl促进了重金属的挥发，降低了综合控制效率。当焚烧温度达到950℃时，重金属排放的最高综合控制效率为78%。此外，还对浸出率、稳定率和综合评价方法进行了比较。采用浸出率和稳定率时结果不一致。相比之下，使用综合评价方法时，结果是协调且唯一的。这项工作可为评估污泥热处理过程中重金属排放的控制效率提供一种有前景的方法。
