EFFECT OF WATER-QUALITY IN FREENESS TESTING

The ISO standards on the drainability tests on pulp require the use of distilled or deionized water throughout the test. However, some anoma lies have been noticed, which originate from the fact that purified wa ter is extremely sensitive to even small amounts of electrolytes that may dissolve from the sample during the test To study the subject, sev eral kinds of pulp and waters with different electrical conductivity w ere used in SR tests The effect of water quality on beating and sheet forming was also studied The results showed that the increase in water conductivity at the lower range has a remarkable decreasing effect on the SR number Little difference exists among the test results with wa ters at the same electrical conductivity but containing different solu ble salts. Finally the effect of water quality on heating and sheet fo rming is negligible.