Dynamic Shear Modulus Degradation Limits in High Speed Recyclable UV Resin Formulations
Dynamic shear degradation limits UV resin velocity at 280 m/min to prevent oligomer scission, balancing resin costs against full EPR fee savings.
Screening Reject Ratio
Separation Index
Efficiency measurements in recovered pulp cleaning evaluate the proportion of material discarded during screening. The screening reject ratio compares the mass of contaminants and fiber rejected by the screen to the total mass of the incoming feed. This metric helps operators monitor the condition of screen baskets and the cleanliness of the pulp.
A high ratio indicates that the screen is removing a large amount of material, which can include both debris and usable fiber.
Fiber Loss
Usable cellulose frequently ends up in the reject stream due to fiber entanglement or high flow rates. Long fibers often form networks that catch on the screen slots, leading them to be washed out with the contaminants. This unintended loss reduces the yield of the recycling process and increases the cost of raw materials.
To minimize this effect, paper mills use multi-stage screening systems that wash the reject stream to recover trapped fibers before disposal.
System Control
Adjusting the pressure drop and feed consistency allows operators to optimize this rejection level. High consistency increases the viscosity of the slurry, causing more fiber to bypass the accepts channel and enter the reject line. Changing the rotor speed inside the screen basket can disrupt these fiber mats, allowing the individual fibers to pass through while keeping the larger contaminants on the other side.
Fine-tuning these mechanical variables prevents screen clogging and ensures a steady supply of clean pulp for high-speed paper machines, which reduces downtime and saves energy. By maintaining the screening reject ratio within a tight band, the mill can maintain a balance between pulp cleanliness and process yield.