Strength of paper made from pulp containing surface active, carboxyl compounds

A process for preparing an aqueous papermaking suspension containing pulp fibers and a polyelectrolyte complex, comprising:

• a) providing an aqueous suspension comprising pulp fibers, surface active carboxyl compounds and water soluble anionic polymer;
• b) adding to the aqueous suspension water-soluble cationic polymer that is reactable in the aqueous suspension with the anionic polymer to form the polyelectrolyte complex, and a compound containing a multivalent cation having at least a +3 charge;
• and
• c) forming the polyelectrolyte complex;
• wherein said compound containing a multivalent cation is added at a level such as to provide an amount of cation equivalent on a molar basis to the amount of aluminum present in alum added at a level of from about 1.5% to about 6% based on the dry weight of pulp fibers.