Low temperature thermal upgrading of lateritic ores

A process for concentrating nickel values contained in lateritic ores, comprising:

• (a) forming agglomerates incorporating the ore, a solid reductant and a sulfur-bearing agent;
• (b) feeding the agglomerates to a reaction vessel having a feed end and a discharge end, the discharge end having a burner for the partial combustion of a fossil fuel to thereby produce combustion gases, such that the agglomerates and the combustion gases flow counter-currently within the vessel to gradually heat the agglomerates to a final temperature as they pass through the vessel from the feed end towards the discharge end, whereby the iron and nickel values in the ore are selectively reduced;
• (c) retaining the agglomerates in a metallics growth zone, the metallics growth zone being located adjacent the discharge end of the vessel and characterized by a generally constant final temperature and an atmosphere equivalent to the partial combustion of natural gas at between about 60-65% aeration, to prevent re-oxidation or further reduction, and to allow for the formation of distinct ferronickel particles;
• (d) cooling the agglomerates in an inert atmosphere at a rate sufficient to substantially prevent the disproportionation of wustite to magnetite;
• (e) grinding the agglomerates;
• and
• (f) magnetically separating the magnetic fraction of the ground agglomerates.