Commercial Landed Cost Variance Mechanics and De Inkability Fee Surcharges in Packaging Grade Substitution
Commercial landed cost variance depends on sheet yield, press spoilage, and EPR de-inkability fee surcharges triggered by grade substitution.
Hydrophobic Detachment
Flotation Action
Recycled paper processing separates ink particles from wood fibres using chemical and physical flotation mechanisms. This separation process, known as hydrophobic detachment, occurs when synthetic foaming agents and air bubbles lift the non polar ink from the wet pulp slurry. The detached ink particles attach to rising air bubbles and form a foam layer on the surface of the cell.
Chemistry Control
Controlling the pH and surfactant concentration of the pulp slurry is necessary to optimize this separation efficiency. Calcium soap collectors form bridges between the ink and the air bubbles, which enhances the rate of hydrophobic detachment. If the pH is too low, the soap fails to precipitate, which leaves the ink bound to the wood fibres.
This control ensures that the recovered pulp reaches the high brightness required for new printing papers and reduces the need for chemical bleaching agents.
Pulp Recovery
Removing these ink particles prevents grey discolouration and increases the optical quality of the recycled paperboard. Clean pulp fibers stay in the slurry while the ink foam is skimmed off and disposed of or burned for energy. This separation allows paper mills to use high percentages of recycled material in high grade packaging.