| 摘要 |
<p>Improvements in chemical recovery of NaOH and thermal recovery of residual black lyes resulting from the mfr. of cellulose consists of continuously carbonating, at 70-85 degrees C and 0.5 kg/cm2, the residual lyes resulting from the treatment of wood or straw, previously concn. to 40% or 10-15% respectively. The lye, introduced continuously into the upper part of a tower, is dispersed and falls down the tower while O2, introduced at the lower part of the tower, rises. This gives, for the lye from the treatment of straw, a liq. in which silica and part of the lignin ppte. The ppte. is sepd. from the liq. in a rotary filter at ambient temp. and the lye passes to an evapn. stage. The mass of pptd. silica and lignin is treated with a 0.3% alkaline soln. of NaOH to dissolve the lignin, which is then added to the lyes passing to the evapn. stage. The improvements give a simpler evapn. process, an increase in the amt. of lignin obtd. a simpler carbonation appts. and a uniform yield, since the process is continuous.</p> |
