ＭｇベースＳＣＰについて ３ 廃液の腐食性および濃縮燃焼性

Abstract

Comparison of corrosion activities, boiling-point rise, and swelling values of the waste liquors from the five different methods of magnesium-base semichemical pulp was made and discussed here. Remarkable weight loss of the killed steel was found in the waste liquors with low pH as shown in Fig. 1, but no weight loss of the stainless steel used for the test was observed. When the acidic liquors were neutralized with alkali, corrosion decreased considerably as shown in Fig. 2. However, the order of weight loss in both tests corresponded to the order of the pH value of the original waste liquors as follows : Two-components>High-yield sulfite>Magnefite>Vapor-phase magnefite>Slurry. As shown in Fig. 4, except the viscosities of the waste liquor from the magnefite method, it was found that the higher the organic content of the supernatant liquor, the higher the viscosity within a range of 10 to 47% solids of the waste liquors. Prominent increase in viscosities of the five waste liquors with 60% solids was observed. The order of viscosities at 60% solids was quite different from that of viscosities at 47% solids and as follows : High-yield sulfite> Two-components>Slurry>Magnefite>Vapor-phase magnefite. On the other hand, difference in boiling-point rise between the five waste liquors was small. Out of the five waste liquors with 47% solids, the two-components liquor revealed an unusually high swelling value, but those of the other four seemed to be considerably affected by the viscosity of the respective liquor. However, the order of swelling values of the five waste liquors with 60% solids was found to be completely accordant with the order of viscosities of the corresponding waste liquors described above. As a whole, findings presented here suggest that the magnefite or the vapor-phase magnefite method may be more preferable than the others within a range of the experiments studied.