Ca(OH)2 dispersions of different concentrations were prepared by mixing appro- priate amounts of NaOH and CaCl2 at room temperature with different concentrations of NaOH and CaCl2, as shown in Table 1. The mixing was done in a 500 mL beaker, and the resulting mixture was stirred for 30 minutes to ensure proper mixing. Then the mixture was left for a while before mixing it into the pulp stock.