Quantitative Mineralogical Comparison between HPGR and Ball Mill Products of a Sn-Ta Ore

• Published in: Minerals (Basel) Vol. 8; no. 4; p. 151
• Main Authors: Sarbast Ahmad Hamid, Pura Alfonso, Hernan Anticoi, Eduard Guasch, Josep Oliva, Marek Dosbaba, Maite Garcia-Valles, Marina Chugunova
• Format: Journal Article
• Language: English
• Published: MDPI AG 01-04-2018
• Subjects: ball mill; grinding; high-pressure grinding rolls; liberation; process mineralogy; tantalum
• ISSN: 2075-163X
• DOI: 10.3390/min8040151

The mineralogy and liberation characteristics of the comminuted Penouta leucogranite host of the Sn-Ta ore were determined. Grinding developed by a combination of high-pressure grinding rolls (HPGR) followed by a ball mill (BM) was compared with a single ball mill process. The mineral characteristics of the grinding products were analyzed using a Tescan Integrated Mineralogical Analyzer (TIMA-X) and X-ray powder diffraction (XRD). The ore contains 103 ppm of Ta and is mainly composed of quartz, albite, microcline, muscovite, and kaolinite. Nb, Ta-rich minerals are columbite-(Mn) and tantalite-(Mn), as well as minor microlite and wodginite. The liberation in the product is high in the size fraction of less than 250 µm (51–52 wt % for columbite-group minerals (CGM) and 74–80 wt % for cassiterite) and reduced in larger particles (8.8–17 wt % for CGM and 28–37 wt % for cassiterite). The recovery in the −250 µm fraction was high, while in the larger fraction it is limited, remaining up to 80 ppm in some tailings. The combined use of HPGR and a BM reduces the particle size distribution of the product and, thus, increases the liberation of the ores. Smaller fractions can be treated directly using gravity methods; however, particles of a size greater than +250 µm should be ground more.