A method for causing or facilitating the flow of dispersions of solid particulates in liquids, having characteristics of high viscosity or resistance to flow, with particular reference to sludges from purification plants of civil or industrial wastes, which method comprises the addition to the dispersions of silicones of formula ##STR00001## wherein R and R' are identical or different and represent a radical chosen between C.sub.1-C.sub.5 alkyl and aryl; x is an integer comprised between 3 and 2000.