Preconcentration of Nickel Values from Lateritic Chromite Ore Overburden, Sukinda, Orissa, India

Abstract

The nickeliferrous chromite ore overburden of Sukinda, Orissa, contains about 0.55% Ni, and forms an important resource for nickel in India. This deposit has hitherto evaded exploitation because of its lean grade and complex mineralogy. The techno-economics of the metallurgical extraction process developed for recovering nickel from this laterite requires a minimum of 1% Ni; hence there is need for preconcentration. This paper presents the results of batch and semi continuous pilot plant scale preconcentration studies carried out on a representative overburden sample. Two alternative flowsheets involving classification and classification-flotation were developed for preconcentrating the nickel rich iron oxide fines (−37 µm). The first flowsheet gave preconcentrate analysing 1% Ni with 50% recovery and with the use of a hydrocyclone of d50(, =30 µm, it should be possible to increase the recovery to > 60%. The second flowsheet gave a preconcentrate analysing 1% Ni with 65% recovery.