Effect of Wet Versus Dry Grinding on Rejection of Pyrite and Non-Pyritic Minerals from Pittsburgh No. 8 Coal by Flotation

Abstract

The effect of grinding mode on the efficiency of separation of pyrite and non-pyritic minerals from Pittshurgh No. S scam coal hy froth flotation was investigated. In the case of minus 600 micron feed, grinding mode had no effect on the efficiency of separation of cither pyrite or non-pyritic minerals. With minus 75 micron feed, however, the selectivity achieved with the wet ground feed was higher than that ohtaincd using the dry grind and this was attributed to the dry state aggregation of coal with mineral matter. Comparison of flotation selectivity and washahilitv curves showed that entrainment of fines due to water flow was the reason for the loss of selectivity during flotation of coal from non-pyritic minerals. In the ease of pyrite, in audition to entrainment. flotation of pyrite due to its natural hydrophobicity contributed to the loss of selectivity.

Key words:

• Coal cleaning
• flotation
• dry grinding
• wet grinding
• Pittsburgh No. 8 coal
• coal pyrite
• washability

Additional information

Notes on contributors

P. SOMASUNDARAN

To whom correspondence should be addressed