Mining solutions provider MBE Minerals’ pneumatic flotation technology, Pneuflot, with installations in more than 70 plants around the world, has proven to be highly effective on a number of African ores in the last few months, says MBE Minerals development manager Greg Niekerk.
The company has been involved in test cam- paigns ranging from ultrafine coal to coarse flaked graphite and phosphates. In each case, Pneuflot, which introduces conditioned and aerated pulp to the flotation cell through its patented aerator, has exceeded the metallurgical performance of the comparative standard Denver bench scale tests.

“Optimal bubble particle contact at a high-energy intensity in the Pneuflot aerator, which, by design, is self-aerating for most applications, leads to a higher product recov-ery, higher plant efficiencies, lower wear and overall operating costs and a smaller plant footprint in certain applications,” stresses Niekerk.

Quality Upgrade

Niekerk highlights that it is estimated that about 60-million tons of discarded coal fines are generated each year from coal mining operations in South Africa.

“Discarded coal fines are stored in tailings facilities, which represents a major environmental liability for coal producers and society. It also carries a significant ongoing operational cost. “According to a 2003 DME Discards Report, recently updated for MBE Minerals by consulting group XMP Consulting, at least a billion tons of discard remains today despite what may have been reclaimed over the last 20 years.”

Although sometimes of a direct saleable quality and certainly saleable after upgrading through a process such as flotation, coal fines have had to be dumped as they cannot be conveyed or moved through existing logistics chains from mine site to end-user, owing to the behaviour of coal fines when coming into contact with water.

“The industry, intent on finding a solution to this problem, has made great strides in its research into finding a briquetting technology to agglomerate the ultrafines into a larger single particle that would behave like a small coal product and thus be transportable,” says Niekerk.

However, briquetting itself is expensive. One way to possibly render a coal fines project financially viable is to increase the value of the final product by upgrading the current arisings from an existing plant or a dump through flotation.

Having installed more than 80 Pneuflot units in 12 countries, treating some 25-million tonnes a year of fine coal slurries, MBE Minerals introduced Pneuflot into South Africa in 2012. “We have joined forces with the local coal industry, to which we have been a technology and equipment supplier for more than 40 years, in support of the industry’s efforts to produce products with suitable specifica-tions for a number of higher-end markets,” says Niekerk.

Earlier this year, MBE Minerals produced a bulk flotation concentrate sample, with its 10 m3/h Pneuflot pilot plant, to customer specification for black-controlled mining company Exxaro at its Delmas colliery.

MBE Minerals also conducted laboratory testwork using its laboratory scale Pneuflot cell on Waterberg and Soutpansberg fines. “We were able to achieve ash grades as low as 11.5% and 10% respectively at acceptable organic efficiencies,” says Niekerk.

He adds that, last month, the company completed a series of test campaigns on phosphate minerals and graphite from East and West Africa, which yielded positive results.

Future Frontiers
“MBE Minerals aims to explore the applica-tion of Pneuflot in the iron-ore, platinum and gold sectors in which it has achieved considerable success in the recent past in South America and Eastern Europe,” says Niekerk.

The company in June commissioned a reverse iron-ore flotation plant in Chile and believes that there is scope for converting iron-ore fines and tailings, in the Northern Cape and in West Africa, into saleable products, through Pneuflot, followed by agglomeration.

The Pneuflot laboratory cell has also been used by research organisation Mintek in research work it is conducting on chrome, iron-ore and platinum-group metals.

“Like many others, we are able to provide an end-to-end service for our customers, from initial testwork through to detailed design, implementation and after-sales care. Our experience over the last 20 years is that our customers invariably become repeat buyers of Pneuflot,” Niekerk concludes.