抄録
The changes of purity of (NH4)2SO3•H2O crystal, kept under various conditions, were observed. When exposed to the air, it decreases its purity rapidly by oxydation. In comparison with the protecting abilities of the packing materials from the oxydation, the polyvinyl chloride film has a supereority to the polyethylene film. In storing aqueous (NH4)2SO3, it was observed that one having the higher concentration was more stable.
The effects of (NH4)2SO4, contained in NH3 base cooking liquor as a impurity, on the cooking were studied. It acts to accelerate the cooking reaction and a lower yield of pulp is given, until its content in cooking chemical reachs to about 20%. When the content increases over the limit, the yield of pulp rises gradually. Those phenomena are explained by the observed facts that (NH4)2SO4 has an action of accelerating the cooking reaction and of decomposing the SO2 in the cooking liquor. (Fig. 7)
Finally, the effects of the liquor to wood ratio on the cooking were studied. It was observed that the lower the liquor ratio, the cooking was more accelerated and pH of the cooking liquor was kept more stable.
Both the ammount of (NH4)2SO4 and the liquor ratio have no direct effect to the qualities of pulp.
