Modification Challenges of Precipitated Calcium Carbonate (PCC) Fillers and Their Application in Papermaking Industry

This study employs an inorganic powder precipitation coating method, utilizing barium sulfate generated from aluminum sulfate and barium chloride reactions to modify PCC surfaces. Experimental investigations focus on the effects of modified PCC fillers on paper solubility, drainage properties, and optical performance.

Introduction
Surface modification technology plays a crucial role in optimizing inorganic powder materials, significantly enhancing their application value. In papermaking, calcium carbonate's inherent solubility in aqueous systems limits its compatibility with neutral/acidic papermaking processes. Our research demonstrates that barium sulfate coating effectively reduces PCC solubility while improving paper whiteness (77.2% optimal) and opacity (90.1% peak).

1. Modification Experiment
1.1 Materials

• PCC (Industrial grade, XX Chemicals)

• Cationic dispersing rosin emulsion

• Aluminum sulfate/Barium chloride (Analytical grade)

• Bleached bamboo pulp (29°SR beating degree)

1.2 Procedure

1. Prepare PCC suspension (fixed concentration)

2. Add BaCl₂ solution under controlled agitation (25°C/90°C)

3. Introduce Al₂(SO₄)₃ solution dropwise

4. Maintain reaction (8h@25°C + 3h@90°C)

5. Filter, wash, dry (105°C), and pulverize

Paper sheets were prepared with 15% filler content using optimized vibrating screen-assisted particle size distribution control.

2. Results Analysis
2.1 Solubility Characteristics

2.2 Drainage Performance
Beating degree increased proportionally with BaSO₄ content, peaking at 29°SR (8% dosage). This correlates with enhanced surface roughness requiring specialized vibrating screen separation techniques.

2.3 Optical Properties

3. Conclusion
The barium sulfate coating modified PCC demonstrates:
✓ 11.6% solubility reduction
✓ 6.3% whiteness improvement
✓ 41% scattering coefficient increase

Vibrating screen technology proves critical in maintaining consistent particle size distribution (1-5μm optimal range) throughout the modification process, ensuring uniform barium sulfate deposition and enhanced papermaking performance.