Mining is a big industry and is extremely important as well. Many other sectors depend on it heavily for materials and it is crucial for economies as well. However, mining is not environmentally friendly and requires a lot of energy. Now scientists from the University of Toronto came up with an idea – microwaves could help reducing the environmental impact of mining and mineral processing.
In fact, to prove the effectiveness of this method scientists are using an actual microwave – a common house appliance. During mining processes, ores are extracted and they contain high-value metals and minerals. However, the majority of their mass is just a low-value rock and separating the two is not easy. Scientists say that valuable elements, such as nickel, copper and zinc react differently to microwaving than low-value stuff (gangue) and therefore this process could become more sustainable. Scientists drilled holes in some rocks and put small reactor vessel inside of them to prove it.
Microwave radiation, in theory, should be able to produce tiny little cracks between the valuable grains and the gangue. Furthermore, it should also alter the surface of the ore, allowing simpler processing methods. But for this idea to work well, microwaves have to be adjusted perfectly, because tolerances are very tight. Scientists are also thinking about other methods that could potentially reduce water consumption and waste production in the industry. In fact, a lot of ore is dumped as waste just because valuable contents of it are too small for extraction to be worth the effort.
Scientists think that using some innovative methods could reduce the cost of processing of low-grade ore. They think that improving the process of comminution (breaking up multi-tonne slabs of rock into particles the size of grains of sand and smaller) is the key, because currently it is very energy-intensive. That is where microwave comes in – it could, said simply, soften the rock, making comminution easier and more energy-efficient. It means that ores that previously were thrown away because of their low contents of valuable elements could be processed too. Using such a simple technique could, potentially, reduce energy consumption and waste of entire industry, which would be a huge achievement.
However, scientists are still playing around with this idea using a conventional microwave, which is not the way to go. Only when they reach the scale of the ordinary mineral processing plant the world will recognize it as an achievement.