Secondary Recovery of Columbite from Tailing Dump in Nigerian Jos Mines Field

摘要

Millions of tons of tailing dump at Rayfield mine in Jos in North Central Plateau state of Nigeria have been found to contain large quantity of columbite. Initial attempts to recover columbite concentrates by local miners and mineral speculators from the columbite rich tailing dump failed due to the ineffective processing route employed. Using cone and quartering sampling method, 0.5 kg of the columbite tailing was obtained for sieve and chemical analyses. 50 kg of <1mm fraction of the sample was subjected to a first stage magnetic concentration in a three poles Dry High Intensity Magnetic Separator (DHMS) that separated the columbite in the third pole. The re-grind of the + 0.355 mm rougher concentrate fraction (containing interlocking columbite) to pass the sieve aperture was treated on the DHMS in the second stage. The rougher concentrate undersize and columbite pre-concentrate of the first stage magnetic separation were then gravity concentrated on the air float machine. The Rayfield tailings and final concentrate were assayed using ED-XRFS to obtain 12.5% and 69.6% Nb2O5, respectively. The recovery and separation efficiency were 77.95% and 77.88% in that order. The magnetic and gravity concentrations were found effective at 77.95% recovery for columbite from the Rayfield tailing dump. This study also provided database for optimum recovery of columbite from tailings of mining sites of similar composition.