Introduction
It is important to recall that the initial objectives of the research are to develop fundamental understanding and techniques to predict cornmunition behaviour from a universal test based on an experimental rig that reproduces single impact on a target in an air jet mill. The influence of the material properties on breakage in ultra-fine grinding are investigated. In Previous reports gave results for the impact of seven kinds of particles on a target and showed different types of behaviour. A classification was obtained (see report AR 27.03). A second rig has been built to study another impact configuration namely that of the impact between two jets of particles. Experiments are also performed with other types of mill and in particular an Alpine 100 AFG air jet mill. Morphological analysis is developed to study the shape of particles, debris and the action of the mills. In addition progress in the development of a model of an air jet mill is presented.
Part A of this report presents the results of the experiments performed with the single jet apparatus. Eight kinds of alumina particles impacted on a target are studied : three hydrargillites and five calcined hydrargillites.The influences of the material processing, the structure, and the calcination on the behaviour at impact are highlighted.
Part B presents the methods being developed for morphological analysis and gives results from the experimental impact rig and other methods of particle breakage.
Part C presents results towards the modelling of an air jet mill. In particular measurements and analysis of pseudo batch grinding experiments leading to the first determination of breakage and selection matrices for an air jet mill.