(19)

(11)

EP 0 809 615 A1

(12)

(43) Date of publication: 03.12.1997 Bulletin 1997/49 (21) Application number: 96945253.0 (22) Date of filing: 13.12.1996

(51) International Patent Classification (IPC):  C05F 3/ 00( . ) (86) International application number: PCT/US1996/020453 (87) International publication number: WO 1997/021647 (19.06.1997 Gazette 1997/26)

(84) Designated Contracting States: AT BE CH DE DK ES FI FR GB IE IT LI LU NL PT (30) Priority: 15.12.1995 US 19950573043 (71) Applicant: Power Plant Aggregates of Iowa, Inc. Sioux City, IA 51102 (US)

(72) Inventors: GREENE, G.L.-Power Plant Aggregates of Iowa, Inc. Sioux City, IA 51102 (US) JENSEN, M.R.-Power Plant Aggregates of Iowa, Inc. Sioux City, IA 51102 (US) JORGENSON, M.D.-Power Plant Aggregates of Iowa I. Sioux City, IA 51102 (US) ZIMMERMAN, L.-Power Plant Aggregates of Iowa Inc. Sioux City, IA 51102 (US) (74) Representative: Thomson, Paul Anthony  Potts, Kerr & Co. 15, Hamilton Square Birkenhead Merseyside L41 6BR Birkenhead Merseyside L41 6BR (GB)