PURPOSE: To provide an additive improved in dispersion properties, by preparing a polymer contg. structural units (A) of a specific formula and structural units (B) of a specific formula at a predetermined ratio and having a predetermined average mol. wt.
CONSTITUTION: Polyaspartic acid is modified with an org. amine, or polysuccinimide is modified with an org. amine and hydrolyzed to prepare a polymer having a polyamide skeleton and an average mol. wt. of 500 to 500,000. This polymer has structural units (A) constituted of at least one kind of structural units represented by the formulae I (wherein R1 is H or methyl; and X is an alkali metal, an alkaline earth metal, an org. amine, or the like), and structural units (B) constituted of at least one kind of structural units partly represented by the formulae II (wherein Y is NR2R3; and R2 and R3 are each 1-1OC alkyl, alkenyl, aryl, or the like) at an (A)/(B) ratio of 99.9/0.1 to 80/20. A slurry is mixed with 0.02 to 2wt.%, based on the wt. of coal, of this polymer as an additive, and, if necessary, an antisetting agent, a chelating agent, etc., to obtain a high-concn. coal-water slurry.
FUJII GIICHI
NISHIBAYASHI HIDEYUKI
TAWARA HIDEYUKI
