In the second series of tests, the pulps were diluted after digestion and adjusted to about 30% more by volume to reduce supersaturation and prevent spontaneous precipitation. The temperature of the pulps was kept at 70 °C and stirred. Then 0.1 M sodium hydroxide was added drop wise to modify the pH of the leach solution to values of 2, 4, 6, and 8. When the set pH was attained the pulps were maintained at the pH and stirred for half an hour before samples were taken, diluted and the impurity content determined.