D.I.I.A.R. Environmental Section, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy.
Waste Manag. 2013 May;33(5):1174-81. doi: 10.1016/j.wasman.2013.01.037. Epub 2013 Feb 28.
Waste incineration bottom ash fine fraction contains a significant amount of aluminium, but previous works have shown that current recovery options based on standard on-step Eddy Current Separation (ECS) have limited efficiency. In this paper, we evaluated the improvement in the efficiency of ECS by using an additional step of crushing and sieving. The efficiency of metallic Al recovery was quantified by measuring hydrogen gas production. The ash samples were also tested for total aluminium content with X-ray fluorescence spectroscopy (XRF). As an alternative to material recovery, we also investigated the possibility to convert residual metallic Al into useful energy, promoting H2 gas production by reacting metallic Al with water at high pH. The results show that the total aluminium concentration in the <4 mm bottom ash fraction is on average 8% of the weight of the dry ash, with less than 15% of it being present in the metallic form. Of this latter, only 21% can be potentially recovered with ECS combined with crushing and sieving stages and subsequently recycled. For hydrogen production, using 10MNaOH at 1L/S ratio results in the release of 6-11l of H2 gas for each kilogram of fine dry ash, equivalent to an energy potential of 118 kJ.
焚烧炉底灰细颗粒含有大量的铝，但以前的研究表明，目前基于标准单步涡电流分离（ECS）的回收方法效率有限。在本文中，我们通过增加粉碎和筛分步骤来评估 ECS 效率的提高。通过测量氢气的产生来定量测定金属铝的回收效率。还使用 X 射线荧光光谱法（XRF）测试灰样的总铝含量。作为材料回收的替代方法，我们还研究了将残余金属铝转化为有用能源的可能性，通过在高 pH 值下使金属铝与水反应来促进 H2 气体的产生。结果表明，<4mm 的底灰部分的总铝浓度平均占干灰重量的 8%，其中不到 15%以金属形式存在。在后一种情况下，只有 21%可以通过与粉碎和筛分阶段相结合的 ECS 潜在回收并进行回收。对于氢气生产，使用 10MNaOH 以 1L/S 的比例，每公斤干细灰释放 6-11l 的 H2 气体，相当于 118kJ 的能量潜力。
