| 摘要 |
PROBLEM TO BE SOLVED: To clean scales in a pulp digester, etc., with a slight influence exercised over surrounding environment without a risk of corrosion of an apparatus by using an aqueous solution of a specific acidic amino acid derivative as a cleaning liquid. SOLUTION: An alkaline aqueous solution at pH >=9 containing >=5 wt.% of one or more kinds of an acidic amino acid derivative represented by the formula (n is 1 or 2), its alkali metal salt, an ammonium salt and an amine salt thereof, e.g. N,N-dicarboxymethylaspartic acid (salt) and/or N,N- dicarboxymethylglutamic acid (salt) is used as a cleaning liquid for cleaning scales in a digester or peripheral equipment thereof in a process for producing a kraft pulp.
|
