Synthetic ore samples to test microwave/RF applicators and processes

Abstract

Recent studies have shown that microwaves heat some minerals faster than others. This creates the opportunity to use microwaves to selectively heat minerals to enhance separation of valuable minerals from gangue minerals. This opportunity has been investigated by studying the heating process under controlled conditions. It involved creating synthetic samples of ore using pyrite grains suspended at known locations within a matrix made of quartz and poly(methyl methacrylate).Previous experiments used cement or plaster as the matrix however, these compounds are slow to set and allow the mineral grains to settle to the bottom of the mould during the setting process. This disadvantage has been overcome by using a cost-effective mixture of quartz and poly(methyl methacrylate) (PMMA). The experimental work presented in this paper has shown that it is possible to use this mixture to place mineral grains at precise locations within the matrix, and that the bulk dielectric properties of the matrix are similar to those of pulverised quartz sand. It was also determined that the optimum ratio of 10% of PMMA (as adhesive) was the minimum mass proportion that can be used, to create the designed mineral texture without compromising mechanical properties of synthetic samples. The synthetic ore samples were resistant to breakage and could be used in multiple tests. The work in this paper demonstrates a method for creation of synthetic samples as well as their use in assessment of selective microwave heating in different types of microwave applicators.