Laboratory study to evaluate methods for deinking water-based - - PowerPoint PPT Presentation

“Laboratory study to evaluate methods for deinking water-based flexographic printed ONP ”

Akpojotor Shemi Pulp and Paper Engineering

Oil based ink newsprint Flexographic ink newsprint

Furnish type

Ink Properties

50 microns 1 microns Size (diameter) Hydrophobic Hydrophilic Surface Chemistry Properties Oil Water Solvent Hydrocarbon resins Acrylic resins* Binders Carbon black Carbon black Pigment Oil based ink Flexographic ink Composition *Acrylic resins

Conventional flotation assisted with electric field

α β χ φ ε δ γ +

• φ

η ι

α) is the float cell β) channel for rejects

• verflow

χ) outlet for circulation of pulp slurry δ) pump ε) air injector φ) pipe in which electric field treatment takes place γ) air from air compressor η) power source supplies electrical voltage ι) inlet for circulation of pulp slurry. The float cell is equipped with heat exchange for temperature control

Why flexographic inks are problematic

Poly acrylic acids as binders

Binds ink to the paper

Dispersant

Keeps the carbon black particles dispersed and

stable

All carbon black have chemisorbed oxygen

complexes (i.e., carboxylic, quinonic, lactonic, phenolic groups Ionization

Fully ionize at alkaline conditions. Negatively

charge

Behavior of ink particle dispersion.

Total potential energy as function of distance of separation between two particle To the right of the energy barrier, the suspension is stable To the left of the energy barrier, the suspension is unstable The double layer model is used to visualize the ionic environment in the vicinity of a charged colloid and explains how electrical repulsive forces occur.

Summary of deinking technology

Two pH stage treatment

Modified ink size High cost of pH change

Organically modified clay

Adsorption unto clay White water dead load

Electric field technology

Electric volts, bubble size

68.3 7079 178 302 1700 506 70.8 7079 141 238 1500 400 68.0 7079 94 78 1000 267 67.5

• % delta E

Volume of bubbles (ml) dispersed air Volume of bubbles (ml) Electrolysis of water No of bubbles (millions) 25μm volts Current (Ampere)

• Deinking efficiency improves with increasing current and voltage.
• The number of bubbles increases with increasing current and voltage.

Pulping time, Temperature and Electric field

X1x2x3

• 0.5

41.4 20 43 e.f. X2x3

• 0.3

39.3 20 43 no e.f. X1x3 1.0 39.7 20 30 e.f. X3

• 4.7

35.4 20 30 no e.f. X1x2

• 0.5

45.7 5 43 e.f. X2 3.1 44.5 5 43 no e.f. X1 2.2 42.3 5 30 e.f. 41.4 41.0 5 30 no e.f. Estimated effects % Change in ERIC Pulping time (min) x3 Temperature (oC) X2 Electric field x1

• Both Electric field and Temperature improves deinking efficiency.
• But pulping time has an negative effect on deinking

Z-weighted factor.

3.6 4.0 12.9 15.6 2347 2284 3663 3830 30 30 1.25 25 25 7.8 10.3 12.5 11.8 1712 1621 3767 3770 10 10 1.25 48 48 5.9 7.9 5.7 8.6 2797 2282 3964 3911 1.25 25 25

Z- we ig hte d fa c tor Solid loss E RIC (Ac c e pt) E RIC (fe e d) Surfa c ta nt (mic r

• -lite rs)

E KA RF 4031 E le c tric fie ld (Kvolts) T e mpe ra ture (oC)

• Typically in deinking operation there is a direct correlation between

ERIC reduction and yield loss

16 30 10 1 5 1000 15 30 10 1 5 14 30 10 1 1000 13 30 10 1 12 30 10 0.5 5 1000 11 30 10 0.5 5 10 30 10 0.5 1000 9 30 10 0.5 8 1 5 1000 7 1 5 6 1 1000 5 1 4 0.5 5 1000 3 0.5 5 2 0.5 1000 1 0.5 Experiment no. Soap (µL) Surfactant (µL) x4 Consistency (%) x3 NaOH (ml) x2 Electric field (volts) x1

Electric field, pH, consistency, surfactant & soap dosage

Electric field, pH, consistency, surfactant & soap dosage

• 200
• 100

100 200 300 400 GRAND x1 x2 x1x2 x3 x1x3 x2x3 x1x2x3

• 200
• 100

100 200 300 400 x4 x1x4 x1x2x4 x2x4 x3x4 x1x3x4 x2x3x4 x1x2x3x4

X1, X2, X3, X4 all had positive effect on deinking efficiency X2 has the most positive effect on deinking efficiency

500 1000 1500 2000 2500 3000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Feed Accept Feed-Accept

Electric field, pH, consistency, surfactant & soap dosage

ERIC

Electric field, organoclay, alkaline charge

X1x2x3

• 62.76

1197.6 + + 1250 X2x3

• 42.91

1196.7 + + X1x3 0.71 724.8 +

• 1250

X3

• 189.08

721.55 +

• X1x2

61.58 1491.6

• +

1250 X2 516.83 1366.6

• +

X1 1.36 807.5

• 1250

1197.55 931.2

• estimated

effect delta ERIC Organoclay 0.5% (250ulCT/0.5%(0.25)clay x3 NaOH / alkaline (pH)(mL) 4ml sodium silicate, 4ml sodium hydroxide X2 Electric field X1

Surfactant

FEED and ACCEPT ERIC and percent reduction in ERIC 500 1000 1500 2000 ERIC 25 30 35 40 45 50 % reduction in ERIC Feed accept % ERIC reduction

Nonionic anionic cationic,quat, Amphoteric Ctab

1. Cetyltrimethyl ammonium bromide (CTAB) 2. Quaternary ammonium compounds, dicoco alkyldimethyl, chlorides 3. Alkyldiphenyloxide Disulfonate 4. Amphoteric 5. Non ionic Surfactant

• Cationic surfactant has better yield
• Amphoteric surfactant was not effective
• Nonionic and anionic reduce ERIC with lower yield

Organoclay and electric field

+ 1000 4 + 3

• 1000

2

• 1

Organoclay 1%(500ul arquad C-75) 0.5%(0.25)clay Electric field volts Experiment No

500 1000 1500 2000 2500 1 2 3 4 Feed Accept Feed-Accept

ERIC

• Yield was 86%
• BRIJ 700 Nonionic surfactant was

used in all experiments

What contributes to deinking and ERIC reduction with electric field?

• Fine bubbles
• Hydrogen peroxide generation
• Electric field detachment of ink particle that are easily attached to

bubbles

• Generation of metal ions
• Possible agglomeration of ink particles
• Poly acrylic acid

Summary

Factorial design of experiment was used to

evaluating deinking variables

Deinking efficiency is improved with the

introduction of electric field

Z factor shows that deinking efficiency is

improved with justifiable yield

Thank you

• Dr. Hsieh

International Paper Danny Haynes

Questions