An investigation into the parameters affecting mass flow rate of ore material through a microwave continuous feed system

An investigation into the characteristics of a gravity-driven conveyor system for passing crushed ore through a microwave cavity has been undertaken using laboratory experiments and numerical modeling. The conveyor system consisted of a vertical hopper, a column passing through the microwave cavity and a tilting vibrating tray. For the efficacy of the microwave treatment of the ore, the residence time of the ore material in the cavity must be known so that the optimum microwave power and exposure time can be calculated, and so that the microwave field can be tuned effectively. The investigation was undertaken using a crushed copper ore from the Palabora mine, South Africa. Four different size fractions and two blends of ore were tested, and the affect of tilt angle and distance between the base of the column and the collector tray were examined. Equivalent numerical models were constructed using discrete element modeling. It was found that the numerical models can be calibrated against the experimental data, and thus can be used to predict flow characteristics, mass flow rates and microwave exposure times which are required in the design of such a conveyor system for microwave pre-treatment.