Deinked Pulp

Recycled Stock

Recycled cellulosic fiber obtained by processing recovered paper to extract print pigments and adhesive contaminants constitutes a primary raw material for graphic and packaging paper production. Commonly known as deinked pulp, this material provides an alternative to virgin wood fibers in manufacturing paperboards and tissue grades. Production of this material focuses on maximizing brightness while minimizing residual ink levels to ensure the pulp meets specific runnability and optical standards on high speed paper machines.

Ink Extraction

Flotation and washing processes govern the mechanical separation of hydrophobic ink particles from hydrophilic wood fibers. In the flotation cell, injected air bubbles attach to the dispersed ink chemistry and carry them to the surface as foam. This mechanism depends heavily on surfactant chemistry to modify the surface tension of the pulp slurry.

Agitation and washing then remove smaller particles that escape the foam layer. Alkaline chemicals, primarily sodium hydroxide and sodium silicate, are introduced during the pulping stage to swell the fibers and release bound ink.

Sheet Integrity

Papermaking utilizing secondary fiber must account for reduced fiber length. Because recycling shortens fibers, deinked pulp exhibits lower tensile strength than virgin kraft pulp. Additives are therefore applied to restore sheet strength.

Raw cellulose fibers and a pinned kraft paper swatch are mounted on a grey display board inside a paper mill.

Zero-Span Tensile Extended Producer Responsibility Scott Bond

Paperboard Recycled Content Chain of Custody Verification Basics

Paperboard recycled claims require matching chain of custody certificates, mass balance ledger reconciliation, and certified converter invoices.

A square hexagonal honeycomb substrate section rests atop a glass jar surrounded by nested paper circles inside a digital render.

Short Span Compression Test Deinked Pulp Virgin Softwood Kraft

Paperboard Middle Ply Furnish Compression Mechanics under Static Bench Conditions

Middle ply CTMP bulk provides structural moment of inertia, while short-span compression bench testing quantifies network collapse risks under load.

A molded pulp bottle prototype rests on a layered metal platform with a steel mixing vessel visible in the background laboratory.

Folding Boxboard ISO 9184 Chain of Custody Ledger

Physical Fiber Verification versus Mass Balance Ledger Accounting in Paperboard Procurement

Mass balance ledgers allocate administrative fiber credits across mill networks, but laboratory microscopy governs physical batch compliance at customs borders.

Piles of fibrous raw material sit on a white testing desk beside a magnifying lamp inside a paper production facility.

Canadian Standard Freeness Shenk-Western Specific Refining Energy

Dynamic Chemometric Calibration Transfer Protocol Drift in Recycled Pulp Furnish Matrix Nodes

Dynamic calibration transfer standardizes online near-infrared sensors across recycled furnish nodes, maintaining prediction accuracy across shifting pulp matrices.

Large rectangular bales of compressed brown cardboard and kraft paper stand vertically stacked outside a dark industrial shed near corrugated metal cladding.

Spectral Reflectance Factor Darcy Permeability Recycled Testliner

Predictive Dynamic Dot Gain Modeling across Non-Linear Micro-Porous Secondary Fiber Substrate Matrices

Dynamic tone expansion modeling across recycled fiber matrices requires coupling transient capillary suction with viscoelastic nip deformation metrics.

Industrial grade white paper rolls travel through tensioned guide bars on a heavy duty steel frame inside a commercial scale conversion facility.

Tensile Energy Absorption ISO 536 Alkyl Ketene Dimer

Silent Paper Grade Furnish Substitution Mechanics at Machine Gate

Furnish substitutions at the machine gate require wet end NIR tracking and ISO 1924 tensile verification to prevent runnability failures and yield losses

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