Process for adjusting the pH of a cellulosic pulp, production of pulp or paper from cellulosic pulp and use of (bi)carbonate removal for reducing the consumption of acid

摘要

Abstract The invention relates to a process for adjusting the pH of a cellulosic pulp in a pulp and/or paper mill, and to the production of pulp, paper or board from so treated cellulosic pulp. In the process, the pH of an alkaline cellulosic pulp is adjusted at least 5 twice with carbon dioxide before a neutral treatment and at least once with a strong acid before a subsequent acidic treatment. Between the first and the second carbon dioxide induced pH adjustment there is provided a (bi)carbonate removal step, which reduces the buffering capacity of the pulp. The invention also relates to the use of (bi)carbonate removal for reducing the consumption of acid in the treatment of a 10 cellulosic pulp.