| 摘要 |
Substantially stable slurries containing 30-35% by weight of sodium dithionite are manufactured by evaporating sodium dithionite solutions while maintaining the heating medium at 220 DEG -250 DEG F. and the solution and slurry at 110 DEG -155 DEG F. under a vacuum of at least 25 inches Hg and by promptly cooling the resultant slurry while agitating it. The vacuum is preferably 26.5-27.5 in. Hg. At 4-5% by weight of the sodium dithionite and preferably at 4.3% by weight, NaOH is preferably added to the solution or alternatively to the slurry, immediately after evaporation. A chelator is preferably added to the solution to prevent metal contamination thereof. Zinc-derived sodiation liquor is the preferred sodium dithionite solution.
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