| abstract |
A method for efficiently removing non-magnetic foreign material, from a carbonaceous material dispersion in which carbonaceous material particles are dispersed in a dispersing medium, includes applying the dispersion to a primary filter a specified number of times in circulation, the primary filter including at least one filter device; and applying the dispersion treated with the primary filter to a secondary filter a single time, the secondary filter including at least two filter devices arranged in series. Each respective filter device to be used satisfying following conditions: (a) a variation of cumulative undersize distribution Q [%] with respect to a reference particle diameter and a variation of non-volatile content, before and after passing the carbonaceous material dispersion, being not more than 0.1%, respectively; and (b) a removal rate of particles with a threshold particle diameter being not less than 20%. |