The enhancements to TankCell technology— including FloatForce and Flow- Booster features—were outlined by Outotec at showings of a 300-m3 TankCell, the world’s largest mechanical flotation cell and the first of three 300 m3 cells being water commissioned in Perth at the time of the conference. Outotec is delivering these units to OceanaGold’s Macraes operation in New Zealand.

At the Macraes mine, 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. Macraes will be the first such installation, with completion, which includes installation and commissioning, scheduled for September 2007.

The initial Macraes TankCell-300 showcased Outotec’s new FloatForce rotor and stator mechanism, which features customized setups for fine-, mid- and coarse-sized particles. According to the company, this technology has demonstrated increased recoveries over conventional mechanisms through optimized primary pumping and air dispersion, while the secondary impeller enhances the mixing flow patterns in the upper region of the cell, thus increasing the cell’s overall mixing and flotation efficiency.

FloatForce’s enhanced rotor characteristics result from extensive R&D, said Outotec—including CFD modeling, with the new design incorporating a reconfigured pumping channel and separate air dispersion slots.

“This offers sustained pumping under high aeration rates and enhanced suspension of coarse solids,” said Peter Bourke, Outotec’s global technology manager–flotation process. “It also produces decreased sanding and minimized friction losses, with the impact angles resulting in lower wear.”

FloatForce’s stator characteristics include a focus on critical flow areas, with wear restricted to a small, welldefined area. The elevated fixing surface employs single blades, with replacement of a stator’s blades considerably shorter, allowing for quick, easy and safe maintenance, according to the company.

Another recent innovation shown in Perth was FlowBooster technology, which employs an auxiliary agitator to enhance the flow patterns in the top part of the cell by introducing a downward-pumping action. This in turn accelerates the upward flow of the aerated slurry.

“The design uses existing energy provided by the shaft and features reversibility of the impeller blades,” said Bourke. “When reversing the direction of rotor rotation, there is no need to re-install a new agitator, as the blade pitch changes automatically.”

Bourke maintained that 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 300-m3-plus capacity means that Tank- Cell-300 can cope with a site’s most demanding throughput, still deliver optimum concentrate grade and recovery level,” said Burke. “Not only do we have the largest 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.”