Improvement of filtration properties of mine tailings by grinding with a stirred media mill

T. Kinnarinen*, R. Tuunila, A. Häkkinen, Lappeenranta University of Technology, Finland

The influence of grinding variables on particle size distribution (PSD) and filtration characteristics of Ni-Cu mine tailings are investigated by using a stirred media mill and a pressure filter. In any theoretical approach, the average specific cake resistance is thought to increase as a result of particle size reduction. On the other hand, the width of PSD may also have a great influence on the filtration properties, although this aspect is less frequently discussed in the literature. This study demonstrates how the pressure filtration properties of tailings obtained from a Ni-Cu mine can be improved by appropriate selection of the grinding conditions to produce a narrow PSD. In comparison with non-ground slurry, the average specific cake resistance was reduced by over 50 % when the coarse end of PSD was affected most considerably by grinding. However, the use of unfavorable grinding conditions nearly doubled the average specific cake resistance. The average porosity of the filter cake was increased by 1-28 % due to grinding, and high porosity correlated clearly with good filterability, in spite of the finer PSD.

The results of this study may help in reducing the energy consumption of tailings filtration for the purposes of disposal, as well as increasing the future possibilities of recovering valuable elements from tailings deposited in ponds, which is also likely to require efficient grinding and solid-liquid separation operations....

Session: L1 - Cake Filtration I - Characterization of Filterability
Day: 11 October 2016
Time: 13:00 - 14:15 h