1. Adrian, A.B., McCulloch, H.W., 1966. Pressure leaching of ores with particular reference to the upgrading of aluminate solutions II. Alkaline pressure leaching of Sasol fly ash, Gov. Met. Lab (Repub. SA), No. C 13/65, 13 pp., CA 66: 106649w
2. The application of Primene 81R for the purification of concentrated aluminium sulphate solution from leaching of clay minerals;Alquacil;Hydrometallurgy,1987
3. Balantseva, V.M., Nurmagambetov, S.Kh., Shcherban, S.A., 1982. Effect of the composition of an alkali silicate solution on the chemical beneficiation of ashes. Kompledsn. Ispol’z. Miner. Syr’ya, Russia, CA 97: 200215p
4. Bereza, L.V., Pecherskaya, N.P., Ni, L.P., 1972. Leaching of Ekibastuz coal ashes studied by an experimental planning method, Russia, CA 78: 45744X
5. Bohdan, L., 1986. Method for extraction of iron, aluminium and titanium from coal ash. Lisowyj Uis. Patent L 193 No. 4567,0,26, January 29