Anti-clumping product for salts, simple and complex fertilizers as well as for nitrogenous derivatives, especially on the basis of ammonium nitrate, which might in particular be used in connection with explosives, consisting of a metallic salt of an acid phosphate ester having the general formulas I and II: ##STR1## wherein: R.sub.1 designates an alkylene group having from 2 to 4 carbon atoms,R.sub.1, R.sub.2 and R.sub.3 designate each an alkyl group having from 2 to 24 carbon atoms, or an alkylaryl group whose alkyl part has from 1 to 18 carbon atoms, andn.sub.1, n.sub.2 and n.sub.3 designate an integer from 0 to 15,the cation which is part of the constitution of the above-said metallic salt being a divalent or trivalent cation, especially one of those of the group comprising magnesium, calcium, aluminum, zinc and manganese, it being also possible to select the said cation from the group consisting of sodium and lithium.