Postgalvanic slime was stabilized by addn. of clay minerals (kaolin, bentonite, 3 montmorillonites) and Portland cement (1:1:1 by mass), dild. with H(2)O, formed as pellets (hight 10 mm, diam. 10 mm), dried at 110 degrees C for 12 h, studied for mech. strength (compression), thermal properties and leachability of phosphates and Zn ions in water (after grinding of the pellets). The leachability of phosphates (1.5 g of sample in 50 mL water for 48 h at room temp.) was below 0.84 mg/L Zn ions below 0.01 ppm. Montmorillonite K-10 and kaolin were the most active stabilization agents.