MechChem Africa May-June 2021

FLSmidth high density thickeners double mine output

FLSmidth general manager for projects, Howard Areington, talks about a thickener solution for one of the world’s largest copper and cobalt producers that included six FLSmidth high density, counter current decantation (CCD) thickeners and one pre-leach thickener, each measuring 31 m in diameter.

Featuring the GEMÜ servoDrive actuator design, the GEMÜ F60 servoDrive filling valve is predestined for fast and precise fill - ing of small volumes – approximately 1.0m ℓ to100m ℓ – for applications such as those in the pharmaceuticals industry. Rotary lobe pumps are currently often used inhygienicandasepticfillingprocesses. Using theGEMÜF60servoDrivefillingvalve not only allows these filling processes to be made significantly faster and more flexible, it also extends service life. The GEMÜ servoDrive actuator design excels through its high traverse speed, excellent positioning accuracy and fast W hen one of the world’s largest copper and co- balt producers wanted to double its production rates, it chose FLSmidth to provide a thickener solution that included six of its proven high density thickeners. The order was placed in 2020, and delivery has been completed. The mine, located in the Democratic Republic of Congo (DRC), already had FLSmidth thickeners on site, andwas sat- isfied with their performance. According to FLSmidth general manager projects and account sales Howard Areington, the company’s proposal for the mine’s expanded requirements was based on testwork to confirm the characteristics of the material that would be treated. “The tests confirmed that we could use a similar design to the one we had installed on the mine some years previ- ously,” he says. “This solution included six counter current decantation (CCD) thickeners and one pre-leach thickener, each measuring 31 m in diameter.” These units deliver high solids un- derflow to optimise the recovery of dis- solved metals. In addition to the steeper

controllability. The low-loss, brushless and robust servo motors made from stainless steel satisfy the requirements of electrical protection class IP69K and can achieve 50 to100million cycle duties, depending on the application. An accuracy test was performed with the GEMÜF60 servoDrive for filling the smallest quantities.Theaimherewastoachievetheac- curacy requiredwhenfilling pharmaceuticals of ±0.5% at a filling weight of 1.0 g. The test was performed with water and a continuous pressure of 0.3 bar. The results showed that the requisite accuracy was delivered over multiple measurement series. Further tests floor slope, the FLSmidth thickeners were designed to include a high torque ring gear drive with high tolerances to ensure minimal maintenance over long periods of time. “Our high density thickener design ensures consistently high underflow densities that allows the operator to sustain high production rates and better recoveries,” says Areington. These CCD thickeners are manufac- tured from LDX2101 duplex stainless steel. This provides mechanical benefits without compromising chemical resis- tance, allowing the mass of each unit to be reduced. The pre-leach thickener, which was not exposed to corrosive con- ditions, is constructed from carbon steel. “We also designed and supplied five impurity-removal thickeners, which are high rate thickeners, also in LDX2101 stainless steel,” he says. “The sizes of these units ranged from 20 to 30 m in diameter.” Fabrication of the equipment was done in South Africa, while accommo- dating the demands of the COVID-19 lockdown, which required careful plan- ning and flexibility.With components and platework delivered to site, the welding

The FLSmidth high density thickener design ensures consistently high underflow densities, which allow the operator to sustain high production rates and better recoveries. and construction was conducted by the mine with installation assistance from FLSmidth and its agent in the region. www.flsmidth.com

GEMÜ F60 servoDrive for fast and precise filling

with various small volumes also confirmed the filling accuracy. A filling cycle time of significantly less than one second could be achievedwith all fill volumes. The GEMÜ F60 servoDrive allows faster filling cycles than the rotary lobe pumps that are currently often used. In addition, various filling volumes can be implemented without havingtomodifythefillingplunger.Alongside fillingof pharmaceutical products, theGEMÜ F60 servoDrive is also suitable for any filling applications where accuracy, speed and hy- giene are required, such as foodstuffs or bat- tery filling and chemical dosing applications. www.gemu-group.com

22 ¦ MechChem Africa • May-June 2021