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对生态和社会产生影响的背景下，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嵌布金属的废物，具有很大的潜力，目前尚未开发。虽然粗粒二次原料的处理是最先进的，但由于工艺要求的增加和对所含合成金属相缺乏了解，通常不会从细粒废物和废物馏分中回收金属。例如冶金和焚烧厂产生的炉渣、底灰和烟道粉尘，以及电子废料机械加工产生的粉尘。在本项目范围内，将以垃圾焚烧底灰细馏分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，我们对从这些馏分中浮选合成铜相的研究显示了有希望的结果。然而，为了进一步发展这种方法，缺乏关于金属相的物理化学性质以及这些相与浮选试剂之间相互作用的基本知识。为了缩小这一差距，首先，选择有代表性的垃圾焚烧和垃圾衍生燃料底灰将在项目内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体相，确定重要的浮选特性（特别是zeta电位、接触角），然后研究这些相与可能合适的浮选剂（捕收剂、抑制剂、活化剂和起泡剂）之间的相互作用。这些研究将用单个成分和混合物进行。在项目的最后三分之一，将研究所得结果对真实底灰的可转移性。

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.