Microwave Technology Unlocks Refractory Ores
 
A revolutionary new process using microwaves to unlock gold, copper and other metals from refractory hard to recover ores is being brought to commercial realisation by BATEMAN.

Microwave technology is particularly suitable for the pretreatment of ores in which the metals are not directly recoverable due to the association of other elements such as sulphur and arsenic. It offers cost savings and more effective metal recovery and can also make commercially viable those mineral reserves which have previously been rejected as uneconomic because of the difficulties of extraction.

The basic technology was developed in Canada by EMR Microwave Technologies. EMR has run pilot plants successfully for a number of years in which microwaves were found to be able to breakdown or modify sulphide, carbonaceous and other materials shielding the valuable minerals in ores.

BATEMAN recently made a significant investment in EMR to boost the development of this technique. This fits in perfectly with BATEMAN’s strategy of investing in new niche technologies in its areas of expertise which offer long term rewards.

The technology could have significant impact in the processing of platinum group and base metal ores and heavy mineral sands. Applied to sulphide flotation concentrates, it would have huge potential to replace historic pretreatment processes such as autoclaving, roasting or smelting.

The equipment required for minerals processing applications will essentially be conventional. It is easy to adapt designs to maximise the energy efficiency of the microwaves and handle large feed stocks. Microwave equipment is well proven with a long lifespan, simple to maintain and easily meets environmental safety standards.

Although it is a high-energy microwave process, it uses less electricity than other pretreatment methods. The combination of large reductions in both capital and operating costs means potentially very significant savings in production costs.

For example it would offer significant cost savings when preparing sulphide gold-bearing ore for cyanide leaching compared to autoclaves and roasters. The process would also be far more environmentally friendly.

While this technology is not applicable to all ores, the results in difficult to treat ores can be impressive. In tests on a Mexican ore in which both gold and silver were trapped, with at least 50 % of gold unrecoverable by cyanide leach, the microwave treatment resulted in up to 95 % gold recovery.

The process is completely safe. The industrial use of microwave energy is in at least its third decade of worldwide application and is widely used in ceramics, pharmaceutical and chemical synthesis, glue and rubber curing and the sterilisation and incineration of hazardous materials.

The business venture between BATEMAN and EMR will bring commercial applications of microwave technology to the mining industry. For more information, please contact your nearest BATEMAN office (see web site ‘Contacts’ page).
 
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