Particle Size and Its Effect on Flotation Performance of a Well Liberated Zinc Ore

Mineral flotation is the most widely used separation process applied for the concentration of metals sulphide particles from finely ground ores. However, flotation is a process that often has many problems which can affect its efficiency, mainly due to: • Variability of the feed stream characteristics • Inability to measure important process variables, such as the mineral floatability • A lack of understanding of the effect of circuit configuration and the mineral behaviour through the circuit The aim of this thesis is to investigate these issues using a steady state model applied to industrial data. The plants examined in this thesis were the Pillara Concentrator in Western Australia and the Charcas Concentrator in Mexico. In both cases the zinc circuit was surveyed to provide data for evaluation of simulation methods. The main characteristic of these ores is that the minerals are well liberated, and thus, the properties of flotation models can be evaluated without the confounding effects of composite particles. In terms of model building, there are a number of papers in the literature that offer models of various aspects of the flotation process such as chemistry, hydrodynamics, process kinetics, characterisation of the mineral flotation properties, and phase effects. The current JKMRC model methodology was developed in order to put together some of these aspects for the cases where the chemical environment remains constant. With aid of relatively simple well liberated ores this thesis investigates the combined use of plant data and batch cell flotation results from the various plant streams, as a means of determining additional properties of the process streams in the plant. It is shown that additional useful information is available for the batch tests. It is both an advantage and a problem that different types of data are obtained from the batch cells and the continuous plant cells. The ability of the models to predict is limited by the staged addition of reagent that change, as might be expected, the flotation properties of the ore. It is found for constant reagents and froth recovery that the models are capable of predicting the performance of parts of the industrial flotation plant. A recommendation for further work on the effects of froth recovery and reagents is made