System and process for sulfonating mechanical pulp fibers

Abstract From the Canadian patent

A highly economical system and process for enhancement of mechanical pulp wood fibers presented in a relatively high consistency slurry form featuring in use thereof the steps of mixing a portion of said slurry and a sodium sulfite solution in proportioned amounts to dilute said slurry to a level of consistency not materially in excess of 7% and expose surface portions of its fiber content to and provide contact thereof by a relatively minor portion of the sulfite of said solution to initiate reaction therebetween and commence sulfonation thereof limiting said mixing to a relatively brief interval of time then, placing the so diluted slurry in a quiescent state wherein its fiber content is …