Delivering enhanced and sustainable productivity solutions through technology while simultaneously driving down operating costs for minimal expenditure has become minerals processing specialist FLSmidth’s business philosophy.
Having successfully delivered on this vision with the introduction of its REFLUX Classifier (RC) plant, the company is now working to achieve similar benefits through other technologies which most recently includes innovations to significantly improve the recovery of ultra-fine materials in flotation.
This article first appeared in Mining Review Africa, Edition 4 2018
FLSmidth’s new business philosophy was born out of the mining industry’s need to adapt to a new environment which has seen companies reduce capital expenditure and subsequently new project start-ups.
The focus shifted towards increasing operational performance and it looks likely to remain this way for the foreseeable future.
As a result it has become one of FLSmidth’s primary customer service objectives.
“The delivery of our RC technology and BOOM/BOOT (build, own, operate, maintain/build, own, operate, transfer) modular plant package is proof that we are living our vision and we are now looking to extend this to other areas of the minerals processing sector.
“Enhancing existing technologies is a key element in achieving this and is an area mining houses are regularly considering,” says Roy Hazell, sales director – sub Sahara Africa.
And through the introduction of the company’s new generation, patented nextSTEP advanced flotation mechanism; the newest design for forced air flotation technology which reduces operating expenditure with the lowest power consumption on the market, FLSmidth saw further opportunity to enhance separation and recoveries in the flotation circuit – specifically for ultra-fine particles in the flotation cleaning circuit.
The ProFlote technology
The patented ProFlote technology – developed in Australia by Ausmetec and offered to customers by FLSmidth through a technology license and marketing agreement – comprises stainless steel tubes which house permanent, high strength rare earth magnets.
These tubes are inserted into existing flotation tanks or flotation conditioners.
As the slurry passes through the cell, it is magnetised by the ProFlote units and aggregations of less than 38 microns paramagnetic minerals occur enabling greater selective mineral recoveries of between 0.5% and 5% of the final metal product.
Fine metals recovery has historically been quite difficult to achieve Hazell notes.
Treating finer particle sizes in parallel circuits, increasing particle velocity and reducing the bubble size are all known to have associated challenges and are often ineffective in achieving similar results to ProFlote.
“When dealing with large scale operations, an increase in recovery of between 0.5% and 5% equates to significant volumes of additional production,” says FLSmidth commercial manager, Terence Osborn.
While the company’s primary focus for the technology is incorporating it into copper sulphide circuits, it is also well suited to galena, sphalerite, precious metals and nickel sulphides – essentially any base metal/paramagnetic sulphide minerals.
Importantly, siliceous gangue and pyrite are unaffected because they have low magnetic susceptibility.
Minimal requirements to deliver maximum results
Achieving additional recoveries in this case does not require heavy capital outlay.
The incorporation of ProFlote requires nothing more than the retrofit of the steel tubes into existing infrastructure (i.e. no interruptions to existing operations) and requires only a small amount of air to operate effectively – so an increase in operating costs is negligible.
This also means a very small footprint is required to install the equipment.
The units, which are designed according to the size dimensions of the flotation tanks, are simple to install and are also self-cleaning to prevent the build-up of ferromagnetic materials and therefore do not require extensive maintenance either.
“Because of the additional revenue this technology immediately delivers, the payback period is short,” Hazell emphasizes.
What is needed upfront?
Because the performance of the ProFlote technology is influenced by on-site plant conditions and process plant parameters – which vary from plant to plant as feed fluctuations, blending variations, etc. change on-site, test work is essential.
“We recommend a four-month full scale test period which guarantees statistically significant results. The ProFlote units are retrofitted to the first cell in the row, either cleaner or rougher.
“But considering this test work should not be detrimental to flotation recovery there can be no risk to the operation in trialling the product. It could even improve concentration in thickening and filtering reducing losses there,” Osborn outlines.
Further to this, FLSmidth is so confident in the technology’s efficacy that it is offering it to customers using the same model as its reflux classifier plants.
“This means we will provide the upfront capital outlay to install and operate the equipment during the test period and once its deliverables have been proven, down to specific predetermined recovery parameters, the customer is then given the option to purchase the equipment. This eliminates almost all risk for the customer,” Hazell outlines.
While Ausmetec has achieved success with its ProFlote technology to date, FLSmidth’s global footprint and strong mining industry connections are expected to elevate it to new levels and enable the technology to gain greater traction in the market.
At present, the company is conducting test work on-site with some of largest copper producers in Zambia.
“Ultimately, because this technology is helping us gain access to mine sites, it affords us the opportunity to discuss additional processing solutions that we have to offer.
“This is significant considering our expertise ranges across all aspects of the minerals processing value chain. Our ultimate intention remains to enhance operating performance and grades, without excessive capital outlay,” Hazell concludes.