44
comminution
Stirring up excitement CITIC Heavy Industries is venturing into the stirred-media mill market
Schematic of a stirred-media mill showing how the casing opens for maintenance
A
high proportion of new basemetal resources are relatively fine-grained. These ultimately require grinding below 45 microns in order to feed downstream processes. As the ground material becomes finer, its surface area increases exponentially, as does the power required to grind it. Traditional tumbling mills have been
used for centuries for fine grinding. However, with the recent developed of stirred-media mills they have become inefficient in comparison, and so stirred-media mills have become the preferred option for regrind and fine-grinding applications in mining. There are only few manufacturers producing stirred-media mills and these are either vertical or horizontal in design. CITIC Heavy Industries has recently developed a line of six vertical stirred mills (see table) capable of handling a wide range of regrind and fine-grinding applications, which complement its conventional grinding mills range. All CSM models, with the exception of the CSM4000 are commercially available. The CSM4000 is currently going through the final design-optimisation stage and will soon be available.
CITIC range of stirred mills CSM800 CSM1000 CSM1200 CSM1600 CSM2500 CSM4000
(800kW) (1,000kW) (1,200kW) (1,600kW) (2,500kW) (4,000kW)
The CSM1200 was launched in September 2013. Three units each with 1,200kW of installed power are currently under manufacture for a copper project in South America where they will replace the mine’s existing conventional regrind mills. CITIC currently has R&D teams in Australia and China working on improving the technology and efficiency of the new models. The company will release further details on the new machines in the near future.
Design features of CITIC stirred mills • Two-stage planetary main gearbox
• • • •
Comminution_Citic_MM1407.indd 44
design, instead of two helical plus one planetary gearbox. The two-stage planetary gearbox offers 2% more efficiency; Better digging-shoe design for reduced scrap metal and easy replacement; Highly efficient soft start motor; Solid main screw shaft; Magnetic shell liners;
• Complete in-house finite-element • • • •
analysis undertaken on the drive screw and main body; Hydraulic jacks to crack the main door for opening; High availability with low maintenance; Assembly and removal of main drive without part dismantling; Optional control panel with PLC touch screen.
09/07/2014 09:45