Solid residues from Italian municipal solid waste incinerators: A source for "critical" raw materials
Solid residues from Italian municipal solid waste incinerators: A source for "critical" raw materials
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DOI：
10.1016/j.wasman.2014.11.005
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发表时间：
2015-11-01
期刊：
影响因子：
8.1
通讯作者：
Meisel, Thomas
中科院分区：
文献类型：
--
作者：
Funari, Valerio;Braga, Roberto;Meisel, Thomas
城市固体废物的焚烧是废物管理系统的重要组成部分，沿着废物回收和处置，并且热处理后产生的固体残余物由于环境问题和有价值金属的回收而受到关注。本研究的重点是从两个意大利城市垃圾焚烧厂（MSWI）的固体残留物中的关键原料（CRM）的含量。我们采集了未处理的底灰和飞灰残渣，即普通炉排炉焚烧炉的两种主要产物，并使用灵敏的分析技术如XRF和ICP-MS测定了它们的总元素组成。在从底灰中去除一些粗金属物体后，使用强消解方法获得相应的ICP溶液，以确保溶解可能含有大量贵金属和CRM的最难熔组分。将准确的化学数据与物质流分析相结合，考虑到质量平衡和不确定性评估，表明底灰和飞灰可以被视为低浓度的贵金属和高科技金属流。镁、铜、锑、锌的含量接近低品位矿石的相应值。评价了底灰与飞灰之间以及底灰不同粒级内部元素流动的分布。大多数元素在底灰流中富集，特别是在细粒级分中。然而，计算出的传递系数表明，锑和锌强烈分配到飞灰。与现有研究的比较表明，未经处理的固体残留物中的CRM浓度与经过处理后澄清的残留物相当，例如亚铁和有色金属部分之间的分离。当物理机械装置不可用或不能在旧的MSWI系统中实施时，建议的单独收集“新鲜”底灰，可以对其进行进一步的矿物升级处理，可以构成废物管理系统的一个有吸引力的选择。建议的方法可使CRM的回收率提高到83%，其它有价金属的回收率提高到94%。(C)2014爱思唯尔有限公司版权所有。
The incineration of municipal solid wastes is an important part of the waste management system along with recycling and waste disposal, and the solid residues produced after the thermal process have received attention for environmental concerns and the recovery of valuable metals. This study focuses on the Critical Raw Materials (CRM) content in solid residues from two Italian municipal waste incinerator (MSWI) plants. We sampled untreated bottom ash and fly ash residues, i.e. the two main outputs of common grate-furnace incinerators, and determined their total elemental composition with sensitive analytical techniques such as XRF and ICP-MS. After the removal of a few coarse metallic objects from bottom ashes, the corresponding ICP solutions were obtained using strong digestion methods, to ensure the dissolution of the most refractory components that could host significant amounts of precious metals and CRM. The integration of accurate chemical data with a substance flow analysis, which takes into account the mass balance and uncertainties assessment, indicates that bottom and fly ashes can be considered as a low concentration stream of precious and high-tech metals. The magnesium, copper, antimony and zinc contents are close to the corresponding values of a low-grade ore. The distribution of the elements flow between bottom and fly ash, and within different grain size fractions of bottom ash, is appraised. Most elements are enriched in the bottom ash flow, especially in the fine grained fractions. However, the calculated transfer coefficients indicate that Sb and Zn strongly partition into the fly ashes. The comparison with available studies indicates that the CRM concentrations in the untreated solid residues are comparable with those residues that undergo post-treatment beneficiations, e.g. separation between ferrous and non-ferrous fractions. The suggested separate collection of "fresh" bottom ash, which could be processed for further mineral upgrading, can constitute an attractive option of the waste management system, when physical-mechanical devices are not available or could not be implemented in old MSWI systems. The suggested procedure may lead to the improvement of recovery efficiency up to 83% for CRM and 94% for other valuable metals. (C) 2014 Elsevier Ltd. All rights reserved.