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Continuous pulping process

  • US 2,904,460 A
  • Filed: 07/22/1953
  • Issued: 09/15/1959
  • Est. Priority Date: 07/22/1953
  • Status: Expired due to Term
First Claim
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1. A PROCESS FOR PULPING WOOD CHIPS COMPRISING SUBJECTING THE WOOD CHIPS TO THE PULPED TO AN ALKALINE SOLUTION HAVING A PH OF ABOUT 8 AT AN ELEVATED TERMPERATURE AND PRESSURE FOR RELATIVELY SHORT PERIODS OF TIME TO SOFTEN THE LIGNIN OF THE WOOD TO PERMIT SUBDIVISION THEREOF IN THE FIBER DIRECTION, SUBJECTING THE SOFTENED WOOD TO A MECHANICAL SHREDDING ACTION TO EXPAND THE SURFACE AREA OF THE WOOD NORMAL TO THE FIBER DIRECTION INTO CHIPLENGTH SPLINTERS HAVING A CROSS-SECTIONAL DIMENSION OF FROM ABOUT 2.3 TO ABOUT 4.7 MM., AND THEN SUBJECTING THE SPLINTERS TO A DELIGNIFICATION TREATMENT OF THE CELLULOSIC MATERIAL BY THE ACTION OF A SOLUTION OF SODIUM HYDROXIDE AND SODIUM SULFIDE AT SUBSTANTIALLY CONSTANT CONCENTRATION AT A TEMPERATURE OF FROM ABOUT 300* TO ABOUT 400* F.

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