Flotation of synthetic metal phases through the example of fine fractions of waste incineration bottom ashes

在资源日益减少以及原材料开采产生的生态和社会影响的背景下，确保原材料供应的替代方法变得越来越重要。特别是含有细粒和细小弥散金属的废物具有很大的潜力，目前尚未开发。虽然粗二次原料的加工是最先进的，但由于工艺要求增加和对所含合成金属相缺乏了解，从细粒废物和废物馏分中回收金属的工作往往无法进行。例如冶金厂和焚烧厂的炉渣、底灰和烟尘，以及机械处理电子垃圾的粉尘。在本项目的范围内，将以垃圾焚烧底灰的细小颗粒的表征和处理为例进行研究。之所以选择它们，一方面是因为它们具有显著的回收潜力，特别是对铜的回收潜力，另一方面，自己对从这些馏分中浮选合成铜相的研究显示出有希望的结果。然而，对于这一方法的进一步发展，缺乏关于金属相的物理化学性质以及这些相与浮选药剂之间的相互作用的基本知识。为了缩小这一差距，首先，将在项目范围内对具有代表性的垃圾焚烧和垃圾衍生燃料底灰进行化学和矿物学表征。然后，将合成最相关的已确定的金属和基质相，并确定重要的浮选性能(除其他外，Zeta电位、接触角)，然后研究这些相与潜在合适的浮选药剂(捕收剂、抑制剂、活化剂和起泡剂)之间的相互作用。这些研究将以单独的成分和混合物进行。在项目的最后三分之一，将调查所获得的结果是否可以转移到真正的底灰上。

Against the background of declining resources and the ecological and social impacts of raw materials extraction, alternative ways to secure the raw material supply raise in importance. Especially wastes containing fine-grained and finely disseminated metals possess a large potential, which is currently unexploited. Whereas the processing of coarse secondary raw materials is state-of-the-art, metal recovery from fine-grained wastes and waste fractions often does not take place due to the increasing process requirements and a lack of knowledge about the contained synthetic metal phases. Examples are slags, bottom ashes and flue dusts from metallurgical and incineration plants as well as dusts from the mechanical processing of electronic scrap.Within the scope of this project, the characterization and processing of fine fractions from waste incineration bottom ashes will be investigated as an example. They were selected because, on the one hand, they possess a significant recovery potential, especially for copper, and, on the other hand, own investigations regarding the flotation of synthetic copper phases from these fractions showed promising results. However, for a further development of this approach fundamental knowledge regarding the physico-chemical properties of the metal phases and interactions between these phases and floatation reagents is missing. In order to close this gap, first, a representative selection of waste incineration and refuse derived fuel bottom ashes will be characterized chemically and mineralogically within the project. Afterwards, the most relevant identified metal and matrix phases will be synthesized and important flotation properties determined (inter alia zeta potential, contact angle) followed by studies on interactions between the phases and potentially suitable flotation reagents (collectors, depressors, activators and frothers). These studies will be carried out with individual components as well as mixtures. In the last third of the project, the transferability of the obtained results to real bottom ashes will be investigated.