Treatment of mechanical pulp to remove resin

US4922989A · kind A · utility

Assignee

• Kamyr AB · SE

Inventors

• Ake Backlund · Karlstad, SE
• Olof Ferritsius · Karlstad, SE
• Goran Tistad · Karlstad, SE

Key dates

• Filing date: Oct 15, 1985
• Grant date: May 8, 1990
• Expiry date: Oct 15, 2005

Classification

• Technology area (CPC D): Textiles; Paper
• CPC primary: D21D5/02
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

Resin is removed from mechanical pulps, such as TMP, CTMP, and the like, in a quick and simple manner. Mechanical pulp at a consistency of about 7-20 percent (preferably 8-15 percent) is subjected to high turbulence. The high turbulence may be effected by fluidizing the pulp, as in a centrifugal fluidizing pump, or otherwise by subjecting it to high turbulence as in a mixer, screen, or disc mill refiner. By subjecting the pulp to high turbulence treatment for a time period of about 0.2-10 seconds, resin removal is greatly enhanced, and in subsequent dewatering of the pulp a pressate is formed which has a higher concentration of resin in the pressate than in pressates produced by conventional processes. After dewatering the pulp is preferably diluted (again to about 7-20 percent consistency), and the turbulence and dewatering steps are repeated. Chemicals to improve deresination can be added to the pulp while it is subjected to high turbulence.