The company was looking for a useful solution to increase its market competitiveness in thickeners, designed to improve its efficiency and reduce its costs.

Thickeners are used to concentrate solids. In mining process, Thickeners are built to separate the mineral from the water using a gravity sedimentation process. They are big cylindrical tanks, with diameter that can range to over 100m diameter. The material solution is pumped into the tank. The combined effect of gravity and the use of flocculent composites make the minerals aggregate and fall by gravity to the bottom of the tank. Here a rake slowly sweeps the tank, pushing the high mineral content sludge out of the machine through an opening on the bottom of the tank, and then the further processing. The clarified water with low solids contents raises back to the top of the tank, where the excess overflows into an effluent launder.

Bonfiglioli, leader in the production of gear units, offers solutions that guarantee outstanding know-how and cutting-edge technologies, plus the skills to provide tailor-made answers to meet its clients’ requirements.

In this case, Bonfiglioli's solution turned out to be the best choice for a thickener rake drive at a copper mine in the Atacama desert in Chile.
 

The Bonfiglioli planetary 300 series, thanks to the high power density and the compactness is the right choice for this rake drive application, the modularity of this gearbox allows to reach high ratio, fundamental for machine like this in which the output speed is less of 1rpm. The solution is made by two gearboxes, the primary, small size, with the electric motor is installed and the secondary, big size that moves the rake of thickeners. Between these two units, a external load cell is installed in order to prevent the failure in case of peak of torque.

To meet the above requirements, was chosen and used the series 300 size 316 [Torque max 190000Nm].