A Multotec cyclone test unit was used to conduct on-site test work in Madagascar
High levels of wear in mine-to-plant pipelines and other equipment were causing costly downtime and repairs for a mine in Madagascar and it turned to local process equipment specialist Multotec for a solution.
The company shipped a cyclone test unit to site and conducted two weeks of testing, which showed how the levels of coarse chrome in the slurry could be reduced, while also recovering more of the valuable minerals.
Coarse chrome particles in the feed from the nickel laterite deposit were highly abrasive, and causing blockages in pipelines, pump boxes, holding tanks and sumps at the operation. According to Multotec technology division technology manager: research and development Faan Bornman, the aim was to remove the coarse particles using the cyclone underflow, while recovering as much of the valuable cobalt and nickel in the overflow. The coarse material was specified as being between 150 microns and 1 mm in size.
“We were able to identify the cyclone configuration that delivered the best efficiency performance at each sampling point,” says Bornman. At both points, the cyclone spigot was optimised at 20 mm for all the tests.
“Our optimal cyclone configuration at the customer’s first sampling point was able to reduce the coarse chrome content of around 10% in the feed to just over 1% in the overflow,” he explains. This result was achieved using a VV250 flat-bottomed cyclone with four barrels, an A inlet head and an A-type vortex finder; the pressure and feed slurry density were also important variables.
Similar success was achieved by the second sampling point, with a similar configuration but with one barrel. Here, the coarse fraction was reduced from almost 15% in the feed to just 1.2% in the overflow – a reduction of over 90%.