The Journey Begins
You break down a box and toss it in the recycling bin. That simple act kicks off a multi-step industrial process that transforms old corrugated into new paper products. Here is exactly what happens next.
Collection and Sorting
Recycling trucks collect cardboard from businesses and curbside bins. At the materials recovery facility (MRF), cardboard is separated from other recyclables using screens, air classifiers, and manual sorting. Contaminated cardboard (wet, food-soiled, or mixed with non-recyclables) is rejected — this is why keeping your recycling clean matters.
For commercial recycling through companies like Portland Boxes, this step is more efficient because the material is already pre-sorted and clean.
Baling and Transport
Clean cardboard is compressed into massive bales weighing 1,000-1,500 pounds each. These bales are loaded onto trucks and shipped to paper mills. In the Pacific Northwest, we are fortunate to have several mills within a few hundred miles — reducing the transportation footprint.
The price mills pay for recycled cardboard (called OCC — old corrugated containers) fluctuates with global commodity markets. In recent years, prices have ranged from $50 to $150 per ton.
Pulping
At the mill, bales are broken apart and mixed with water and chemicals in a giant blender called a pulper. The agitation breaks the cardboard back down into individual cellulose fibers — essentially reversing the original papermaking process.
The resulting slurry (called pulp) is cleaned of contaminants: staples, tape, labels, coatings, and any remaining ink. Multiple screening and cleaning stages ensure the final pulp is pure fiber.
Forming New Paper
The cleaned pulp is spread onto a moving wire screen where water drains away, leaving a mat of wet fibers. This mat passes through heated rollers that press out remaining water and smooth the surface. The finished sheet is wound into enormous rolls weighing several tons each.
These rolls become new corrugated linerboard, paperboard for cereal boxes, tissue paper, or dozens of other products. A recycled box might become a pizza box, a paper towel, or — full circle — another corrugated box.
The Limitations
Cardboard fibers shorten each time they are recycled. After 5-7 recycling cycles, the fibers are too short to form strong paper and must be composted or landfilled. This is why reuse is always better than recycling — reuse does not degrade the fibers at all. A box reused 5 times and then recycled 5 times gets 10 total lives instead of just 5.