Klein J, Dorge S, Trouvé G, Venditti D, Durécu S
Laboratoire Gestion des Risques et Environnement, 25 rue de Chemnitz, 68200 Mulhouse, France.
J Hazard Mater. 2009 Jul 30;166(2-3):585-93. doi: 10.1016/j.jhazmat.2008.12.006. Epub 2008 Dec 6.
Antimony compounds have a wide range of industrial applications, particularly as additives in flame retardants. To ensure environmentally friendly waste incineration of Sb-rich wastes, it is essential to strengthen the knowledge about the fate of antimony and the potential formation of harmful species. Investigations should be conducted particularly in relation with the main operational parameters controlling the process, chiefly temperature, residence time and air supply in the oven and in the post-combustion zone, prior final adapted cleaning of the flue-gas stream. Experimental studies focusing on antimony behaviour were undertaken through laboratory-scale thermal treatment at 850 degrees C and 1100 degrees C of a Sb-rich halogenated waste, originating from the sector of flame retardants formulation. The configuration of our laboratory experimental device allowed to achieve only low oxidative conditions in the waste bed, but high oxidative strength coupled with high temperature and sufficient gas residence time in the post-combustion zone, as prescribed during the incineration of hazardous wastes. Atomic absorption spectroscopy was used to assess the partition of antimony in the different compartments of the process. The oxidation degree of antimony in the gas-phase was determined by the use of electrochemical techniques, namely polarography coupled with anodic stripping voltamperometry. The partition of antimony between the residual ash and the gas-phase under moderate oxidative conditions in the waste bed was constant, whatever the temperature: the volatilization rate for antimony was approximately 64%, while a approximately 36% fraction remained in the residual bottom ashes. But interestingly, while at 850 degrees C, antimony was mainly present in the gas-phase at a +III oxidation degree, an increase in temperature of 250 degrees C favoured the presence of antimony to its highest oxidation degree +V in the flue-gas stream, a valence known to be involved in less toxic species.
锑化合物有着广泛的工业应用，尤其是作为阻燃剂中的添加剂。为确保对富含锑的废物进行环境友好型的焚烧，加强对锑的归宿以及有害物种潜在形成的了解至关重要。尤其应针对控制该过程的主要运行参数进行调查，主要是温度、停留时间以及焚烧炉和后燃区中的空气供应，然后再对烟道气流进行最终的适应性净化。通过对源自阻燃剂配方领域的富含锑的卤化废物在850摄氏度和1100摄氏度下进行实验室规模的热处理，开展了聚焦于锑行为的实验研究。我们实验室实验装置的配置仅能在废物床中实现低氧化条件，但在后燃区可实现高氧化强度以及高温和足够的气体停留时间，这是危险废物焚烧过程中所规定的。采用原子吸收光谱法评估锑在该过程不同隔室中的分配情况。利用电化学技术，即极谱法结合阳极溶出伏安法来测定气相中锑的氧化程度。在废物床中适度氧化条件下，残余灰分与气相之间锑的分配是恒定的，无论温度如何：锑的挥发率约为64%，而约36%的部分残留在残余底灰中。但有趣的是，在850摄氏度时，锑主要以+III氧化态存在于气相中，而温度升高250摄氏度则有利于烟道气流中锑以其最高氧化态+V存在，已知该价态涉及毒性较小的物种。
