Abstract: The disclosed is a method for producing a dispersion of carbonaceous material in a nonaqueous solvent comprising a nitrogen-containing heterocyclic amide compound with a solvent purity of 99.9% or higher, which comprises: confirming an amine-controlled concentration, in which the concentration of amine components in the nonaqueous solvent is confirmed to be less than 3×10?6 in mass fraction; confirming a moisture-controlled concentration, in which the concentration of the moisture concentration in the nonaqueous solvent is confirmed to be less than 5×10?4 in mass fraction; and dispersing a carbonaceous material added to the nonaqueous solvent that satisfies the conditions in the amine-controlled concentration confirmation and the moisture-controlled concentration confirmation so that the carbonaceous material concentration is 15 to 30% by mass based on the total mass of the dispersion, by stirring and mixing.

Abstract: The disclosed is a method for producing a carbon material dispersion which removes efficiently and reliably metallic components from carbon materials, and that provides a carbon material dispersion of a high product quality and stable electrical properties. The method comprises a first magnetic separation step in which the powdered and/or granulated carbon material C is applied to the surface of a rotating magnetic roll 130 to remove the metallic component M from the carbon material in the dry state of the powdered and granulated carbon material C; and a second magnetic separation step in which a magnet element 310 is placed in a carbon material dispersion D, in which the carbon material from which the metallic component has been removed in the first magnetic separation step is dispersed in a dispersing medium, in advance of the second magnetic separation step.