Oxygen treatment of high kappa fibers

A method of making a high brightness papermaking pulp from recycled cellulosic fiber comprising:

• (a) pre-treating a first recycled cellulosic fiber mix with oxygen;
• said first recycled cellulosic fiber mix having a first high Kappa number greater than 20 prior to pre-treatment and a reduced Kappa number after pre-treatment that is lower than said first high Kappa number by less than 40% to form a pre-treated first recycled cellulosic fiber mix;
• and
• (b) blending the pre-treated first recycled cellulosic fiber mix with the reduced Kappa number with a second recycled cellulosic fiber mix having a second Kappa number lower than the first high Kappa number of the first recycled cellulosic fiber mix to form a blended recycled cellulosic fiber mix;
• and
• (c) oxidatively bleaching the blended recycled cellulosic fiber mix of step (b) in a bleaching vessel;
• and optionally
• (d) reductively bleaching the blended recycled cellulosic fiber mix of step (c) to form a papermaking pulp for use as a furnish supply in a papermaking machine.