Pre-concn. of low grade laterite nickel ores by attrition - producing fine powder with increased nickel content

摘要

Nickel ores of laterite origin are pre-conc. by dry attrition, followed by sieving to recover particles (a) with a dimension below a predetermined value, leaving the coarser fraction (b). Attrition is pref. by milling, to obtain particles (a) 50 mu m, esp. 10 mu m, and particles (b) are pref. re-milled. The mill pref. contains milling bodies or balls, which may be particles of ore obtd. from a previous operation, esp. ore particles 1-5 mm in size. Process is pref. used in conjunction with at least one other method for the physical enrichment of ores. The ores contain e.g. 1.2-3.2% Ni, 2-30% MgO, 8-46% SiO2, 8-43% Fe, i.e. low grade ores. Process increases Ni content in the fines (a) to e.g. 4% so the subsequent melting process to obtain ferronickel is more economic w.r.t. the kW energy required/tonne Ni obtd.