To obtain commercially suitable coal-water slurry (CWS), usage of the appropriate type and amount of chemical additives is necessary from various points of view. Since the properties of coal change from one type to another, it is not possible to find an universal dispersing agent, which is acceptable for all types of coals. Examination of the adsorption behavior of the dispersant and the amount of dispersant which is really necessary to make coal particles disperse in water is very important because of the adverse effect of an excess amount of dispersant on the flow and sedimentation properties of CWS, and the high cost of dispersants. The main objective of our research is to represent how some factors, such as air-oxidation, demineralization, stirring speed, particle size distribution, concentration of slurry and addition stage of dispersant, affect the dispersant adsorption characteristic of formaldehyde condensate sodium salt of naphthalene sulfonic acid. These factors were investigated by using Turkish lignite samples and, consequently, the influence of these factors on the dispersant adsorption behavior was determined and discussed. (C) 2001 Elsevier Science B.V. All rights reserved.