Light Impurity Separator Systems for Corrugated Medium Stock Preparation

Reject Stream Problems in Recycled Corrugated Furnish

OCC and mixed waste furnish for corrugating medium carries 8-15% contaminants by weight: plastics, strapping, foam, textiles and light adhesives. If light impurities are not removed early, they shred into microstickies that deposit on wires, press felts and dryer cans, the leading cause of unscheduled downtime in medium mills. The light impurity separator is the dedicated machine for this duty.

Machine Design and Operating Parameters

A light impurity separator combines a pulping rotor with an up-flow separation chamber. Accepts discharge through a 4-8 mm perforated plate under the rotor while a slow-rotating scraper lifts floating rejects to the reject outlet. Operating specifications for Leizhan units serving 150-600 TPD medium lines: stock inlet consistency 1.5-3.5%, rotor speed 200-350 rpm, installed power 37-160 kW, and accept flow rates of 400-2500 L/s depending on housing size. Installed ahead of the coarse screening stage, the machine typically removes 60-75% of total light contaminants in a single pass.

Measured Impact on Line Performance

Industry operating data for 300 TPD fluting lines shows the effect of effective light impurity removal: pressure screen basket cleaning intervals extended from 5-7 days to 12-15 days, wire seam failures reduced by 30-40%, and felt washing chemical consumption down 15-20%. Reject dryness at discharge reaches 40-55%, cutting disposal transport weight roughly in half compared with gravity-drained rejects. Energy draw for the separator itself runs 6-9 kWh per ton of treated stock, modest against the downtime cost of a single felt-change stop, which on a 300 TPD machine represents 4-6 tons of lost production per hour.

Maintenance and Wear Management

• Rotor blades and extraction plate: inspect every 8-10 weeks; hardfaced versions last 12-16 months in abrasive OCC service
• Scraper chain tension: weekly check to prevent reject carry-over
• Bearing lubrication at 1,500-hour intervals; monitor housing temperature above 70 degrees C as an early failure indicator
• Perforated plate slot measurement every 3 months; wear beyond 1 mm oversize raises debris in accepts

Build a Complete Reject Handling Line

Leizhan Technology engineers full stock preparation lines for corrugated medium, including pulpers, high density cleaners, light impurity separators, trommel screens and reject compactors, sized to the actual furnish contamination level. Send a furnish analysis and capacity target for a system layout and quotation.

📧 leizhanzhang@gmail.com