Pulp and paper-making processes require the use of agitators in many areas of the pulp and paper mill.
Chemical make-up tanks, whitewater wash tanks, Saveall tanks, high-density storage chests that reduce 4% concentrated stock to a more workable 2% before heading for the paper machine, and many other areas use agitators.
A very nicely summarized, easy-to-read, and very practical mixing guide would be Pulp & Paper Agitation
as written by Carl Yackel.