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Materials World magazine
,
16 Dec 2014

The most important technological invention since the industrial revolution – and you may never have heard of it. 

Some time ago I asked a friend, who is a science teacher, to ask his class what they felt was the most important technological invention of the last century. The responses were varied and much as I expected – computers, quantum mechanics, nuclear energy, genetics and electronics being just a few.

What these and any other suggestions have in common is that they are all dependent on metals and minerals. Like it or not, the mining industry is the world’s primary and most important industry. It is the great feeder and without it no other industries would be possible. Every civilisation in history has had a thriving mining industry and it is no coincidence that the various ages of man – the Stone Age, Bronze Age, Iron Age (and now the Silicon Age?) – are named after materials obtained from the ground. It is a truism that everything we use or touch is either mined or grown.

Once an ore has been mined, the various valuable minerals must be separated from the waste minerals before the contained metals can be extracted, and without this stage of mineral processing, extraction would be uneconomic.

Miners have always cherry picked, treating the richest and easiest ores available – such that today, the available ores are often low-grade and difficult to treat. Many modern industries demand metals that were virtually unheard of 20 years ago, such as indium, lithium, germanium and neodymium. Intensive research is therefore needed to keep pace with this increasing pressure on the minerals industry.
Today’s civilisation is dependent on a plentiful supply of the so-called base metals, such as copper, zinc, lead and nickel. Without prior concentration of the valuable minerals in the ore, extraction of the metals from these minerals would be hopelessly uneconomic, effectively making these precious metals.

There is only one process that is available to concentrate these and many other ores, and it was developed more than a century ago, in Australia. Miners’ wives in the Broken Hill district had noticed that dark lead and zinc minerals in the miners’ overalls were sticking to the soap suds when washed. This phenomenon was soon developed into a concentration process, which involved air bubbles being blown into a slurry of ground ore, and the dense sulphide minerals sticking to the bubbles and floating to the surface. Later refinements, mainly due to the development of selective reagents, allowed the process to concentrate specific minerals in the ore. This process, known as froth flotation, is now almost ubiquitous in modern mines. Without it, the modern world would be a very different place. Not only can it claim to be the most important technological development since the industrial revolution, it is probably the most important development since the discovery of smelting, around 8,000 years ago, which dragged man out of the Stone Age and into the world of metals.


Barry Wills

Dr Barry Wills is a founder and senior partner of Minerals Engineering International (MEI) in Falmouth, UK. He was recently awarded the Distinguished Service Award of the International Mineral Processing Council for services to mineral processing, particularly for the role that MEI plays in disseminating information globally via MEI Online (www.min-eng.com) and organising minerals engineering conferences. Read Barry’s blog on mineral processing and its people at www.min-eng.blogspot.com, and follow his news updates on Twitter, @barrywills