Method for the preparation of a pulp

A process for the preparation of pulp comprising:

• i. mechanically milling a vegetable fibrous material at 50.degree.-250.degree. C. to soften its tissue;
• ii. delignifying the milled material by treatment in separate stages with a chlorine-containing compound and ammonia or ammonium hydroxide thereby forming a waste water containing (a) the chlorine-containing compound and (b) ammonia, ammonium hydroxide or an ammonium salt;
• iii. separating the delignified fibrous material from said waste liquor;
• iv. adding magnesium hydroxide to said waste liquor for reaction with said chlorine-containing compound to form magnesium chloride and to release ammonia for recovery;
• then
• v. burning said waste liquor to decompose said magnesium chloride to hydrogen chloride and magnesium oxide;
• vi. absorbing said hydrogen chloride in an aqueous medium for conversion to hydrochloric acid;
• vii. converting said hydrochloric acid into said chlorine-containing compound;
• and
• viii. recirculating the ammonia and chlorine-containing compounds recovered in steps iv and vii to the delignifying step ii.