The invention relates to a hydroxide aqueous suspension of at least one selected transition element of which the potential oxidation reduction is less than that of the pair CrO.sub.7.sup.2-/CrO.sub.4.sup.2- (-0.12 V) having a pH between 2 and 11, limits excluded, for reducing the content of chrome VI of cement to a value no greater than 2 ppm. The suspension is characterized in that it contains 0.5 to 80% by wt. of dry material of hydroxide of at least one transition element with regard to the quantity of water and in that it is stabilized by a hydrosoluble stabilizer. This suspension makes it possible to reduce the content of chrome VI of cements to a value no greater than 2 ppm.