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1. (WO2017153562) PROCESS FOR REDUCTION OF PAPERMAKING WATER HARDNESS AND COD

Pub. No.:    WO/2017/153562    International Application No.:    PCT/EP2017/055645
Publication Date: Fri Sep 15 01:59:59 CEST 2017 International Filing Date: Sat Mar 11 00:59:59 CET 2017
IPC: D21H 17/67
D21H 17/70
D21H 21/36
Applicants: LINDE AKTIENGESELLSCHAFT
Inventors: DÄBRITZ, Peter
OHLWEIN, Marc
JANSSON, Ann-Charlotte
Title: PROCESS FOR REDUCTION OF PAPERMAKING WATER HARDNESS AND COD
Abstract:
The present inventions relates to a process for manufacturing paper or board comprising the steps of providing a pulp suspension, wherein the pulp suspension comprises CaCO3, filtrating the pulp suspension, wherein at least a fraction of the added water is separated from the pulp suspension, and optionally pressing and/or drying the filtrated pulp suspension yielding paper or board. According to the invention an alkaline agent comprising or consisting of CaO and/or Ca(OH)2 is added to the pulp suspension before filtrating until the pH of the pulp suspension is above 8, particularly above 9, more particular above 10, even more particular above 11, yet more particular between 8 and 12, and CO2 is added to the pulp suspension after adding the alkaline agent and before filtrating to adjust the pH to a value between 6,5 and 8, particularly to a value between 7 and 7.5.