Purification and conversion of Malaysian iron ores into industrial grade iron oxide colour pigment

Abstract

This work proposes a method of converting local iron ores into colour pigments to add commercial and technical values to the commodity. Iron ores were subjected to hammer-crushing and two milling techniques (low-energy ball milling and high-energy milling) to produce submicron or ultrafine pigment particles. Effects of different milling duration, speed and charge type on the particle size were investigated. X-ray diffraction and energy-dispersive X-ray spectroscopy scans revealed that the ores contain hematite and goethite phases, with 54% of Fe and 35·38% of O. Particle size analysis showed that high-energy milling (14 hours, 11 mm charge, 550 rev min−1) was effective in producing particles as small as 1·379 µm. Commision Internationale de l'Eclairage L*a*b* colour values measured were L* of 49·7, a* of 21·2 and b* of 15·8.