Mineral Oil Analysis in Recycled Fibre Food Packaging
Verify MOSH and MOAH compliance in recycled fibre packaging using accredited HPLC-GC-FID testing, validated functional barriers, and complete declarations of compliance.
Post-Consumer Pulp Deinking
Fiber Recycling
Industrial chemical and mechanical separation processes remove printing inks, varnishes and adhesives from recovered paper products to produce secondary papermaking fibers. The operation of post-consumer pulp deinking restores optical brightness and cleanliness to recycled fibers intended for graphic papers and tissue grades. Flotation cells and chemical pulping agents release cured ink particles from disintegrating cellulose networks.
Unprinted virgin wood pulps and clean unprinted mill broke require no deinking treatment.
Separation Process
Collected wastepaper undergoes hydraulic repulping in an alkaline water mixture containing sodium hydroxide, sodium silicate and surfactant soaps. Mechanical rotors shear the softened paper sheets into individual fibers while saponifying ink binders and detaching pigment particles from cellulose walls. Dispersed ink particles attach to air bubbles injected into the bottom of flotation cells, floating to the surface as a dark froth that mechanical skimmers remove.
Centrifugal cleaners and fine slot screens then isolate heavy contaminants and adhesive stickies from the cleaned slurry. High water temperatures and controlled pH parameters maintain optimal ink detachment without dislodging fiber wall fibrils.
Quality Limit
Deinked pulp quality depends on the chemical composition of incoming printed inks, where flexographic water-based inks disperse into fine particles that prove difficult to float. Recyclers blend deinked fibers with virgin pulp to maintain specified tensile strength and ISO brightness targets.