Main purpose of refining Chemical Pulp is to obtain higher yield by allowing a higher Kappa level which means more lignin and hemicellulose. This is achieved with shorter retention time in the digester. Less cooking leads to undissolved bundles of fibres, knots and shives. These must be defibrated by means of mechanical refining either Blowline or Hot Stock as first stage application.
Typically, as second stage application there are either a Deshive- or Reject refiner with the main purpose to reduce shives.
