Details

Autor(en) / Beteiligte

• Gilliam, T.M.
• Canon, R.M.
• Egan, B.Z.
• Kelmers, A.D.
• Seeley, F.G.
• Watson, J.S.

Titel

Economic metal recovery from fly ash

Ist Teil von

• Resources and conservation, 1982-08, Vol.9, p.155-168

Erscheinungsjahr

1982

Quelle

Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)

Beschreibungen/Notizen

• Symp. on Resource Recovery and Environmental Issues of Industrial Solid Wastes, Gatlinburg, Tennessee, U.S.A., Oct. 1981. Although most coal combustion ash produced in the United States is discarded as a waste ( > 52 million metric tonne per year), results are presented to show that fly ash can be an economical source of Al sub 2 O sub 3 , Fe sub 2 O sub 3 , and possibly several other metals, many of which are presently being imported. Although several metal recovery processes were studied, only the two of greatest economic potential and widest applicability were given detailed economic evaluation; the direct acid leach of ash with HCl (a minimum treatment process) and a pressure digestion--acid leach (a maximum recovery process). Results show that both methods can remove from fly ash all metals that would otherwise be available for release to the environment after disposal and that a major portion of the leached metals can be separated in saleable form. Economic analyses indicate that the direct acid leach process is most attractive. A capital investment of $38.2 million will be required to handle 9.07 x 10 exp 5 metric tonne (dry basis) of ash per year, producing a net yearly cash flow of $15.2 million. Additional economic benefits will result from the recovery of these metals through elimination of the higher ash disposal costs that may be required for fly ash containing trace metals. National benefits will also result from reduced importation of metals and ores. 15 ref.--AA.