Articles via Databases
Articles via Journals
Online Catalog
E-books
Research & Information Literacy
Interlibrary loan
Theses & Dissertations
Collections
Policies
Services
About / Contact Us
Administration
Littman Architecture Library
This site will be removed in January 2019, please change your bookmarks.
This page will redirect to https://digitalcommons.njit.edu/dissertations/1244 in 5 seconds

The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title: Paper recycling : recovery of secondary fibers by selective wettability
Author: Welshans, Gary Keith
View Online: njit-etd1978-005
(xv, 197 pages ~ 7.9 MB pdf)
Department: Department of Civil and Environmental Engineering
Degree: Doctor of Engineering Science
Program: Civil Engineering
Document Type: Dissertation
Advisory Committee: Liskowitz, John W. (Committee chair)
Perna, Angelo J. (Committee member)
Olenik, Thomas J. (Committee member)
Dresnack, Robert (Committee member)
Perez, Manuel (Committee member)
Date: 1978-05
Keywords: Paper recycling.
Availability: Unrestricted
Abstract:

A separation process has been developed which recovers similar paper grades from a mixed stock by selective wettability. This process capitalizes on the various paper additives which are intended to resist water wetting and result in paper flotation. While water can be used to achieve many desirable paper separations, the detention times required are excessive, and therefore, limit any industrial application. Surface-active agents, in low concentrations, can be used advantageously by reducing the detention times for all paper while the structure of the surfactant can be used to selectively recover similar papers over a controlled time period. Detention times have been established with several ionic and non-ionic surfactants over various concentration ranges. The surface and capillary wetting processes have been determined for a number of different commercial grades including catalog, foodboard, kraft shipping sacks, and others. The governing parameters which were found to retard quiescent water wetting included fiber surface charge, coatings, chemical pulping, sizing agents, wet-strength additives, and basis weights. While all surfactants accelerate paper wetting, the charge of the surfactant is critical in determining a desirable separation scheme. In low concentrations, cationic surfactants effectively separate bleached from unbleached papers; anionic surfactants lowered the detention times of unbleached kraft papers when separated from bleached kraft papers. While non-ionic surfactants accelerate all paper wetting, they are non-specific in separations. From measurements made on the transmittance of cationic surfactants through bleached papers, the surface spreading coefficients were found to be proportional to the detention times. Consequently, at a specific surfactant level the liquid penetrates the pores dispelling the entrapped air so that different grades wet and sink at distinctly different times readily allowing separation. A dynamic batch plant system has been studied which significantly increases the through-put that can be achieved under quiescent settling conditions. It was found that neither paper size nor paper shape had any appreciable effect on the detention times when using this recovery process. Lower detention times could be achieved by increasing surfactant concentrations, the mixing agitation, and the power input, or by reducing the loading rates. This paper recovery process can be used in secondary fiber operations to achieve higher fiber yields resulting in a savings of labor and virgin timber, and a reduction in the solid waste problem.


If you have any questions please contact the ETD Team, libetd@njit.edu.

 
ETD Information
Digital Commons @ NJIT
Theses and DIssertations
ETD Policies & Procedures
ETD FAQ's
ETD home

Request a Scan
NDLTD

NJIT's ETD project was given an ACRL/NJ Technology Innovation Honorable Mention Award in spring 2003