Deinking Process Optimization: High Brightness Recycled Cultural Paper | Leizhan
The Challenge of Recycled Cultural Paper Production
Producing high-quality writing and printing paper from recycled fiber is one of the toughest challenges in our industry.
Core Deinking Equipment Configuration
A modern deinking line for 150-300 TPD cultural paper production needs a carefully sequenced equipment train. Here is the proven configuration Leizhan recommends:
High-Consistency Hydrapulper with D-Top
The pulping stage sets the foundation. Leizhan high-consistency hydrapulpers operate at 13-18% consistency with a dedicated detrashing top (D-Top) that continuously removes lightweight contaminants. Key specs:
- Capacity: 150-300 TPD
- Consistency: 13-18%
- Motor power: 250-450 kW
- Pulping time: 15-25 minutes per batch
- Chemical addition: NaOH 0.8-1.5%, H2O2 0.5-1.0%, sodium silicate 1.0-2.0%
Coarse and Fine Screening — Stickies Removal
Stickies are the number one enemy of cultural paper quality. A two-stage screening system with 0.15-0.20 mm slots removes 85-92% of stickies particles before they reach the paper machine. Leizhan fine screens operate at 1.2-1.8% consistency with 75-110 kW motors.
Flotation Deinking Cells
This is where brightness is won or lost. Multi-stage flotation cells (primary, secondary, tertiary) achieve 92-96% ink removal efficiency. Operating parameters: consistency 0.8-1.2%, air-to-stock ratio 0.3-0.5, residence time 8-12 minutes per stage. Target brightness gain: 12-18 points ISO.
Washing and Thickening — Disc Filter
After flotation, multi-disc filters remove residual ink particles and ash while thickening to 8-12% consistency. Leizhan disc filters handle 150-300 TPD with filtrate clarity below 80 ppm TSS. Power consumption: 4-6 kWh per ton.
Dispersion and Bleaching
For premium cultural paper grades (brightness above 82% ISO), a dispersion system at 25-30% consistency plus reductive bleaching (FAS or sodium hydrosulfite at 0.3-0.8%) adds 4-8 points brightness. Power for dispersion: 50-70 kWh per ton at 1200-1500 rpm disc speed.
Energy and Chemical Cost Analysis
Here is what a 200 TPD deinking line actually costs to run:
- Electricity: 280-350 kWh per ton (full line)
- NaOH: 15-25 kg per ton
- H2O2: 8-15 kg per ton
- Total chemicals: $22-38 per ton
- Total operating cost: $45-65 per ton of deinked pulp
Maintenance Tips for Deinking Lines
- Flotation cell nozzles: Clean every 2 weeks. Clogged nozzles reduce ink removal by 10-15%.
- Screen basket slot measurement: Check monthly with feeler gauges. Slot widening of 0.02 mm reduces stickies removal by 8-12%.
- Disc filter sector bags: Replace every 6-8 months. Torn bags send fiber back to the system — increasing total suspended solids and energy cost.
- Chemical dosing calibration: Verify pump stroke and flow rate weekly. Off-spec chemical dosing wastes $300-800 per day.
Leizhan Deinking Solutions
At Leizhan Technology, we provide complete deinking lines for cultural paper production from 100 to 500 TPD. Our systems deliver final brightness of 78-86% ISO and ash content below 2%. We engineer every line based on your raw material mix and target paper grade.
Need better deinking performance? Email leizhanequipment@gmail.com with your raw material specs and brightness target. We will provide a tailored equipment proposal within 48 hours.