Polymer Barrier Coatings and Pulpability Test Standards
Polymer barrier paperboard compliance requires passing 0.15mm laboratory slot screening with under 15 percent reject mass to prevent EPR fee penalties.
Fibre Yield Calculation
Measurement Method
Quantitative analysis of the dry weight of recovered pulp relative to the initial dry mass of the raw wood or agricultural source material establishes the efficiency of a pulping process. To determine this efficiency, a fibre yield calculation balances the oven-dry mass of the accepted pulp against the starting dry weight of the wood chips. The resulting percentage indicates the loss of dissolved lignin and hemicelluloses during digestion.
This ratio remains a fundamental performance metric for pulp mill operations. High yield indicates that more of the starting wood material is converted into paper, which lowers the raw material cost per ton produced.
Process Variable
Chemical dosage and cooking temperature act as the primary drivers of final output. Hardwood species generally offer higher yields than softwoods because of their lower lignin content. However, prolonged cooking or excess alkalinity degrades the cellulose chains and lowers the recovery percentage.
Mills must balance the target yield against the required physical strength of the resulting paper board.
Operational Impact
Resource planning and chemical recovery capacities are scaled based on these calculated yield values. A lower recovery percentage increases the volume of organic solids sent to the recovery boiler, which can become a bottleneck in mill throughput. Accurate yield monitoring prevents unexpected shortfalls in pulp supply for the paper machine.
This calculation directly influences the pricing of purchased wood fiber.