DISSOLUTION OF FIBROUS SILICATES IN ACID AND BUFFERED SALT-SOLUTIONS

Dissolution of amosite, crocidolite and chrysotile was studied in vari ous acid and buffered salt solutions and the appearance in solution of Mg, Fe, Na, K, Ca, Mn, Ni, Co, and SiO2 was measured. In IN acid solu tions more SiO2 and Mg is recovered from chrysotile than from the amph ibole minerals and, in general, SiO2 and Mg dissolution increases with specific surface area of the minerals. The dissolution of chrysotile is affected by the buffering capacity of the leach solution and the am ount of Mg and SiO2 extracted increased with increasing buffer strengt h of the leach solution. Mg(II) ions and hydroxyl groups are released from chrysotile in a ratio of approximately one to two. Ni and Mg extr actions from chrysotile in acid solution are roughly proportional to e ach other.