Further innovations of some of the advanced flotation technologies have been on display to mining industry engineers in Perth by Outotec, formerly known as Outokumpu Technology.
The enhancements to TankCell technology including FloatForce and FlowBooster technology were outlined by Outotec at showings of its large ever, 300m3 TankCell to delegates at the AusIMM 2007 Mill Operators’ conference last month.
The first of three TankCell 300s was being water commissioned in Perth at the time of the conference, so delegates had the opportunity to see the flotation cell in action. Outotec is delivering three of these units to OceanaGold’s Macraes operation in New Zealand.
A single train configuration of 1/1/1 TankCell 300s, combined with two existing TankCell 150s, will replace the site’s original three trains of column flotation.
TankCell 300, with an active capacity of over 300m3, is the large mechanical flotation cell in the world. The Macraes site will be the first such installation, with completion, which includes installation and commissioning, scheduled for September 2007.
The Macraes TankCell 300 also showcased recent technical innovations such as the FloatForce new rotor and stator mechanism, which features customised setups for fine, mid and coarse-sized particles.
This technology has demonstrated increased recoveries over conventional mechanisms through optimised primary pumping and air dispersion, while the patented secondary impeller enhances the mixing flow patterns in the upper region of the cell, thus increasing the cells overall mixing and flotation efficiency.
FloatForce’s enhanced rotor characteristics result from extensive R&D programmes, including CFD modeling, with the new field-proven design incorporating a reconfigured pumping channel and separate air dispersion slots.
According to Outotec, this offer sustained pumping under high aeration rates and enhanced suspension of coarse solids.
It also produces decreased sanding and minimised friction losses, with the impact angles resulting in lower wear.
The stator characteristics of FloatForce include a focus on critical flow areas, with wear restricted to a small, well-defined area.
The elevated fixing surface employs single blades, and replacement of a stator’s blades is considerably shorter, allowing for quick, easy and safe maintenance.
Another recent innovation shown also in Perth was the FlowBooster technology, which employs an auxiliary agitator to enhance the flow patterns in the top part of the cell by introducing a downwards-pumping action. This in turn accelerates the upward flow of the aerated slurry.
The design utilises existing energy provided by the shaft and features reversibility of the impeller blades. When reversing the direction of rotor rotation, there is no need to re-install a new agitator, as the blade pitch changes automatically.
According to Outotec, the technology built into the Macraes TankCells represents a significant development for flotation technology in general.
Designed to meet ever-increasing demand for greater capacity on-site, the 300m³ plus capacity means that TankCell 300 can cope with a site’s demanding throughput, still deliver optimum concentrate grade and recovery level.
Not only Outotec has the large float cell in the marketplace, but recent innovations such as FloatForce and FlowBooster, suitable across a wide range of sizes and applications, help raise the bar in flotation technology innovations.
The three TankCell 300s at Macraes follow previous proven solutions from Outotec installed over many years. Previous solutions included the company’s flotation, thickening and automation technology, such as two TankCell 150s, two SkimAir SK500 units for flash flotation duties, an on-stream XRF analyser courier 30AP, a PSI 200 for particle size analysis and four Supaflo thickeners.