Formation of critical compounds in recycling slags - a study of the melt chemistry with MD simulations and of the solidified compounds in a micro preparation approach

我们在这个项目中的长期研究目标是了解熔渣的凝固过程。这将有助于以工程人造矿物(ENAM)的形式有效地从火法冶金炉渣中回收关键元素。LiAlO2已被确定为从锂离子电池回收渣中回收锂的很有前途的ENAM。Al的加入支持了其作为主要含锂相的形成。然而，如果熔体中存在锰，其形成几乎完全被抑制。代替LiAlO2，形成了原始的Li-Mn尖晶石固溶体，随后形成了其他几个含Li相。本项目的目的是从分子水平上了解尖晶石固溶体在Al_2O_3、MgO、CaO、Li_2O、SiO_2体系中的凝固过程。我们的方法将包括a)分子动力学模拟最重要的离子，以确定熔体的前体多面体和粘度，以及b)和制备和表征喷墨打印微观样品的基质，以及较少数量的小规模和大规模熔炼的合成炉渣。这些将阐明实际凝固化合物的微观结构和成分。一旦了解了一次凝固过程，这些知识将是强制形成所需的Enam LiAlO2的基础。我们开发的程序可以适用于其他系统和EAM。

Our research's long-term goal in this project is to understand the solidification of slag melts. This will help an efficient recovery of critical elements from pyro-metallurgical slags in the form of engineered artificial minerals (EnAM). LiAlO2 has been identified as a promising EnAM to recover Li from Li-ion battery recycling slags. The addition of Al supports its formation as the major Li bearing phase. However, if Mn is present in the melt, its formation is nearly wholly suppressed. Instead of the LiAlO2, a primary Li-Mn spinel solid solution is formed and, later on, several other Li bearing phases. Our objective in this project is to understand the solidifying processes of spinel solid solution in the system Al2O3, MgO, CaO, Li2O, SiO2 in the presence of Mn on a molecular level. Our approach will include a) MD simulation of the most important ions to identify the precursor polytopes and viscosity of the melt and b) and the preparation and characterization of a matrix of inkjet-printed micro-specimens, as well as of a smaller number of small scale and large scale smelted synthetic slags. These will elucidate the microstructure and composition of the actual solidified compounds. Once the primary solidification is understood, the knowledge will be fundamental to enforce the formation of the desired EnAM LiAlO2. The procedures we develop can be adopted to other systems and EnAMs.