Abstract
High-yield pulps are usually derived from pine wood on account of its anatomical configuration and technology used. Eucalyptus, on the other hand, is a fast-growing species, abundant in many parts of the world, and has thus emerged as an alternative source for many products in the pulp and paper industry. In this particular study, high-yield pulps of Eucalyptus grandis were used. In order to improve their properties, pulps were subjected to chemical treatments with different doses of sodium hydroxide prior to refining (0, 30, 50 and 70 kg/t), at 75ºC temperature, 3% consistency, during 1 minute. The refining process was done in a Bauer disc refiner (Regmed) using various refining times (0, 5, 10 and 15 minutes). Results showed that refining with addition of NaOH did bring significant gains to the eucalyptus fibers regarding strength properties, the dose 50 kg/t being found the most suitable. However, other variables associated with refining could also be modified to further improve the strength properties of eucalyptus pulps, including consistency and refining discs configuration.
Highlights
Eucalyptus pulps have aroused considerable interest in recent years due to their abundance in all parts of the world and to the high productivity and fiber characteristics of the genus which may be used in different applications by the paper industry, including in the mechanical pulping sector (XU; ZHOU, 2007)
Mechanical pulping processes convert wood into high-yield pulps characterized by high bulk, high opacity and low production cost in comparison with chemical processes (HOLIK, 2006; LINDHOLM; KURDIN, 1999)
A major drawback of mechanical pulping is the high energy consumption involved in the process and the inferior strength properties of the resulting pulps (HOLIK, 2006; LINDHOLM; KURDIN, 1999)
Summary
Eucalyptus pulps (hardwood) have aroused considerable interest in recent years due to their abundance in all parts of the world and to the high productivity and fiber characteristics of the genus which may be used in different applications by the paper industry, including in the mechanical pulping sector (XU; ZHOU, 2007). A major drawback of mechanical pulping is the high energy consumption involved in the process and the inferior strength properties of the resulting pulps (HOLIK, 2006; LINDHOLM; KURDIN, 1999). The cost entailed in such process could exceed 35% of the total pulp manufacturing cost, depending on the local conditions (HUHTANEN et al, 2004). For this reason, the wood material and technological processes being used should be carefully evaluated for quality. Thinner-walled fibers, hardwoods tend to be more severely damaged during the mechanical pulping process, their inferior strength properties. Thinner-walled fibers, hardwoods tend to be more severely damaged during the mechanical pulping process, their inferior strength properties. these short-fiber hardwoods have potential for production of mechanical pulp provided that certain changes are made to the relevant processes
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