Global Patent Index - EP 1052326 A1

EP 1052326 A1 2000-11-15 - Use of oxidized white liquor in a kraft mill digester

Title (en)

Use of oxidized white liquor in a kraft mill digester

Title (de)

Verwendung von oxydierter Weisslauge in einer Kraftkochung

Title (fr)

Utilisation de liqueur blanche oxidée dans un procédé Kraft de cuisson

Publication

EP 1052326 A1 (EN)

Application

EP 00109195 A

Priority

US 30978299 A

Abstract (en)

Pulp is produced from wood or other lignocellulosic material by an improved kraft process in which the white liquor is introduced into the digester in at least two streams. A portion of the white liquor is used in an initial stage of the pulping process. Another portion of the white liquor is oxidized to convert reduced sulfur compounds in the white liquor to sodium thiosulfate and/or sodium sulfate, and this liquor is used during a later stage of the process. The benefits of using split sulfidity white liquor to produce pulp are realized by using a combination of white liquor and oxidized white liquor in the pulping process. <IMAGE>

IPC 1-7 (main, further and additional classification)

D21C 3/02; D21C 3/26; D21C 11/00

IPC 8 full level (invention and additional information)

D21C 3/02 (2006.01); D21C 3/26 (2006.01); D21C 11/00 (2006.01)

CPC (invention and additional information)

D21C 11/0057 (2013.01); D21C 3/022 (2013.01); D21C 3/26 (2013.01)

Citation (search report)

  • [Y] EP 0517689 A1 19921209 - KAMYR INC [US]
  • [Y] US 5082526 A 19920121 - DORRIS GILLES [CA]
  • [Y] US 4764252 A 19880816 - SHIN YOICHI [JP], et al
  • [A] EP 0543135 A1 19930526 - AIR PROD & CHEM [US]
  • [Y] DATABASE PAPERCHEM [online] THE INSTITUTE OF PAPER SCIENCE AND TECHNOLOGY, ATLANTA, GA, US; GUGIN, M. YU. ET AL: "Kraft Pulping using Catalytically Oxidized [White] Liquor with Low Sulfidity", XP002142304, retrieved from DIALOG & BUMAZH. PROM. NO. 3: 6-7 (1984). [RUSS.]BUMAZH. PROM. NO. 3: 6-7 (1984). [RUSS.]

Designated contracting state (EPC)

AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

EPO simple patent family

EP 1052326 A1 20001115; AU 3253400 A 20001130; BR 0002290 A 20010102; CA 2307486 A1 20001111; JP 2000345487 A 20001212

INPADOC legal status


2001-04-04 [18W] WITHDRAWN

- Ref Legal Event Code: 18W

- Date of withdrawal: 20010201

2001-02-28 [17P] REQUEST FOR EXAMINATION FILED

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- Effective date: 20001228

2000-11-15 [AK] DESIGNATED CONTRACTING STATES:

- Ref Legal Event Code: AK

- Designated State(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

2000-11-15 [AX] REQUEST FOR EXTENSION OF THE EUROPEAN PATENT TO

- Ref Legal Event Code: AX

- Free Format Text: AL;LT;LV;MK;RO;SI