Investigation of scientific basics of Selective Comminution concerning mineralogical and technological properties of raw materials

越来越多的新开发矿床具有矿物组成复杂、有价组分含量低的特点。矿物颗粒往往更小，共生性更强，有价元素分布在更多种类的矿石矿物中。为了充分释放，矿石必须研磨至较小的产品粒度。粉碎的能量需求随着产品粒度的减小而以高度渐进的方式增加。选择性粉碎导致优选的裂纹扩展和沿沿着断裂，因此允许大颗粒尺寸的高度释放。或者在一个或多个部件中产生优先裂纹扩展和断裂。这导致组分的粒度依赖性分布。贵重物品和废物的分离可以通过随后的分类来实现。因此，选择性粉碎与简单的分级相结合是一种非常有效的分离过程。矿石及其成分的定量描述是有目的地设计粉碎机和选矿工艺的重要基础。重要的成矿和成岩矿物的矿物学性质有据可查。然而，对单个矿物的粉碎特性的知识很少，并且几乎没有研究晶界的特性。因此，该研究项目的目的是系统地研究矿物的性质和粉碎行为，特别是晶界。为了研究矿物学性质与机械应力下裂纹扩展的相互作用，将建造一个试验装置，该装置配有一个可互换压头的偏光矿石显微镜，该试验装置可用于开发一种合适的压头，以可靠地产生Palmqvist裂纹。在Palmqvist裂纹的基础上，研究了晶界的力学性能。与此同时，使用了各种矿物学方法，如计算机断层扫描和定量显微结构分析。选择性粉碎的实验研究伴随着研究项目，并用于微观层面上的测量特性与宏观层面上的选择性粉碎行为之间的相关性。该研究项目为矿物的粉碎行为提供了可靠的定量测定方法，也为科学选择粉碎机械和有目的地设计矿石粉碎过程提供了方法。

More and more new developed deposits are characterized by a complex mineralogical composition and lower contents of valuable components. The mineral grains are often smaller, more intergrown and the valuable elements are located in larger variety of ore minerals. For a sufficient liberation, the ores must be ground to a smaller product particle size. The energy requirement for comminution increases with a smaller product particle size in a highly progressive manner. This energy requirement could be significantly reduced by Selective Comminution.Selective Comminution leads either to a preferred crack propagation and fracture along the grain boundaries and thus allows a high degree of liberation with a large particle size. Or it produces a preferential crack propagation and fracture in one or several components. This results in a particle size-dependent distribution of the components. The separation of valuable and waste can be achieved with a subsequent classification. Thus, Selective comminution is, in combination with a simple classification, a very efficient separation process.A quantitative description of the ores and its constituents is an essential basis for the purposeful design of comminution machines and beneficiation processes. Mineralogical properties of the important ore and rock forming minerals are well documented. Knowledge on comminution properties of individual minerals, however, is low and the properties of grain boundaries are hardly investigated. The aim of the research project is therefore to systematically investigate the properties and the comminution behavior of the minerals and especially the grain boundaries. In order to investigate the interaction of mineralogical properties and crack propagation under mechanical stress, a testing device will be constructed with a polarization ore microscope comprising an interchangeable indenter.The testing device allows the development of a suitable indenter for the reliable generation of Palmqvist cracks. On the basis of the Palmqvist cracks, the mechanical properties of the grain boundaries are investigated. Parallel to this, various mineralogical methods such as computer tomography and Quantitative Microstructural Analysis are used. Experimental investigations on Selective comminution accompany the research project and are used for correlations between the measured properties on the micro level and the Selective comminution behavior in the macro level. The research project provides methods for the reliable quantitative determination of the comminution behavior of the minerals as well as methods for the science-based selection of comminution machines and the purposeful design of the comminution processes in ore beneficiation.