Deinking of paper using magnetic forces
US5685952A · kind A · utility
Inventor
Key dates
| Filing date | Oct 26, 1995 |
| Grant date | Nov 11, 1997 |
| Priority date | — |
| Expiry date | Oct 26, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/64
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method for removal of magnetic ink from pulp stock formed from xerographic and laser printed paper waste comprising feeding such pulped paper waste past one or more magnets for removal of all or substantially all of such magnetic ink. The magnetic ink can be removed by capture or deflection techniques. The preferred pulp slurry has a concentration of 4% or less by weight pulp. The preferred magnetic force to be applied utilizes background magnetic fields in excess of 2000 Gauss and a field gradient in excess of 500 Gauss/cm. Also, a method for improving the recyclability of paper waste having ink thereon which does not normally contain a magnetic component, by utilizing one or more magnetic carriers in the formulations of the printing ink utilized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.