Eudialytes are a nonconventional source for rare earth elements (REE). As the total REE content of eudialytes is relatively low, high-grade mineral concentrates have to be produced. The applicability of magnetic separation and direct selective flotation for the processing of eudialyte ore from Norra Kärr (Sweden) was tested. The eudialyte in the used sample contains around 4 % of REE. Magnetic separation is applicable for eudialyte ore processing. The higher the strength of the magnetic field, the higher the recovery. Recovery of around 81 % of REE was achieved in a two-stage process of rougher and scavenger at a mass reduction of 48 %. The concentrate grade of around 0.76 % REE is not sufficient for further hydrometallurgical processing steps. A newly developed reagent regime for the direct selective flotation of eudialyte from eudialyte ore was tested with different samples. The regime consists of oxalic acid and sodium hexametaphosphate as depressants and a mixture of mono/di phosphoric acid esters as collector, at a pH below 4. This new method proved applicable for raw ore as well as magnetic preconcentrate. Concentrates with grades of around 2 % R Y, Ce, La were produced.
Although there has been much speculation about the potential of Augmented Reality (AR) in teaching for learning material, there is a significant lack of empirical proof about its effectiveness and implementation in higher education. We describe a software to integrate AR using the Microsoft Hololens into UML (Unified Modeling Language) teaching. Its user interface is laid out to overcome problems of existing software. We discuss the design of the tool and report a first evaluation study. The study is based upon effectiveness as a metric for students performance and components of motivation. The study was designed as control group experiment with two groups. The experimental group had to solve tasks with the help of the AR modeling tool and the control group used a classic PC software. We identified tendencies that participants of the experimental group showed more motivation than the control group. Both groups performed equally well.
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