De-inking Overview. What is Deinking? What is Deinking? The removal of ink from a fibre slurry by a combination of Chemical and Mechanical methods De-inking

De-inking OverviewDe-inking Overview

What is Deinking?What is Deinking?

The removal of ink from a fibre slurry by a The removal of ink from a fibre slurry by a combination of Chemical and Mechanical combination of Chemical and Mechanical methodsmethods

De-inking De-inking OverviewOverview

Chemical Methods of Removing InksChemical Methods of Removing Inks

Pulping with caustic, silicate, peroxide, fatty Pulping with caustic, silicate, peroxide, fatty acid/soap and or surfactantacid/soap and or surfactant

Wash De-inking with surfactant/dispersantWash De-inking with surfactant/dispersant

Flotation De-inking with Fatty Acid/SurfactantFlotation De-inking with Fatty Acid/Surfactant



Mechanical Methods of Removing InksMechanical Methods of Removing Inks

Six Methods for removing or changing inks Six Methods for removing or changing inks and contaminantsand contaminants

WashingWashingFlotationFlotationCleanersCleanersScreensScreensKneading/DispersionKneading/DispersionClarificationClarification

Deinking Overview - Deinking Overview - ProcessProcess

Pulper DumpChest

HD Cleaners

HC Coarse Screens2.2mm holes

HC Fine Screens0.25mm slots

Disc Filter

Alkali ThunePresses

Alkali Alkali

Acid

LC Fine Screens0.15mm holes

LC Primary Holes

Poire

CellecoCleaners

Drum Thickener

ThickStockChest

Acid ThunePress

Disperger

MC Dropleg

StorageTower

3 x 1 LamortVerticells

De-InkStockChest

StockSilo

Pulping - What does it do?Pulping - What does it do?

DefiberingDefibering

Ink ReleaseInk Release

Break down of ink particle sizeBreak down of ink particle size


Pulping Chemistry - BasicsPulping Chemistry - Basics

Caustic: Swells fiber to allow rapid defiberingCaustic: Swells fiber to allow rapid defibering

Peroxide: Prevents alkali yellowing of fibersPeroxide: Prevents alkali yellowing of fibers

Silicate: Stabilizes peroxide and adds alkalinitySilicate: Stabilizes peroxide and adds alkalinity

DTPA: Chelates metal ions for peroxide efficiencyDTPA: Chelates metal ions for peroxide efficiency

Fatty Acid/Soap: Aids ink detachment and ink agglomerationFatty Acid/Soap: Aids ink detachment and ink agglomeration

Surfactant: Aids ink detachment and ink dispersionSurfactant: Aids ink detachment and ink dispersion


PULPER PERFORMANCE - Ink BreakdownPULPER PERFORMANCE - Ink Breakdown

# o

f P

arti

cles

2 10 30 100 300

Particle Size (Microns)


Ideal Size forIdeal Size for FlotationFlotation

Too large to floatToo large to float

Too small to FloatToo small to Float

Deinking OverviewDeinking Overview

Surfactant Action in PulpingSurfactant Action in Pulping

Surfactants in the pulper will increase the ink detachmentSurfactants in the pulper will increase the ink detachmentefficiency. Its high detergency means that it will compensateefficiency. Its high detergency means that it will compensatefor some of the caustics mode of action and a decrease in caustic for some of the caustics mode of action and a decrease in caustic is therefore possible.is therefore possible.

Any decrease in caustic will be followed by a decrease in peroxideAny decrease in caustic will be followed by a decrease in peroxide,therefore the overall chemical demand is lower. ,therefore the overall chemical demand is lower.


Common De-inking chemicalsCommon De-inking chemicals

** Sodium Hydroxide Sodium Hydroxide ** Sodium SilicateSodium Silicate** Hydrogen PeroxideHydrogen Peroxide** ChelantsChelants** Fatty Acids/Soaps Fatty Acids/Soaps ** Surfactants Surfactants


Common De-inking Chemicals Common De-inking Chemicals Typical DosagesTypical Dosages

** Sodium Hydroxide - Woodfree - 0.3% - 0.8% on fibreSodium Hydroxide - Woodfree - 0.3% - 0.8% on fibre ONP/OMG - 0.2% - 0.5% on fibreONP/OMG - 0.2% - 0.5% on fibre

** Sodium Silicate - 0.8% - 2% on fibreSodium Silicate - 0.8% - 2% on fibre

** Hydrogen Peroxide - 0.2% - 0.6% on fibreHydrogen Peroxide - 0.2% - 0.6% on fibre

** Fatty acids - Fatty acids - 0.1% - 0.6% on fibre 0.1% - 0.6% on fibre

** Surfactants - Surfactants - 0.03% - 0.1%on fibre 0.03% - 0.1%on fibre


De-inking chemicals De-inking chemicals Advantages and DisadvantagesAdvantages and Disadvantages

ChemicalChemical AdvantageAdvantage DisadvantageDisadvantage

Sodium hydroxide Wetting, fibre swellingSodium hydroxide Wetting, fibre swelling Dispersive action,Dispersive action,

Ink release, neutralisationInk release, neutralisation filler release, fibrefiller release, fibre

of fatty acid, polymers etcof fatty acid, polymers etc yellowing, saponficationyellowing, saponfication

of hot melts etcof hot melts etc

Sodium SilicateSodium Silicate Wetting, buffering, alkalinity Wetting, buffering, alkalinity Dispersive action, colloidDispersive action, colloid

peroxide stabilisationperoxide stabilisation stabilisationstabilisation


ChemicalChemical AdvantageAdvantage DisadvantageDisadvantage

Fatty AcidFatty Acid Rapid efficient removal of Rapid efficient removal of water hardness dependentwater hardness dependent

ink, fewer dispersed inksink, fewer dispersed inks high dose rates, low foamhigh dose rates, low foam

high brightness, high brightness, in flotation, make down in flotation, make down

low cost per kg low cost per kg systems, safety concernssystems, safety concerns

SurfactantSurfactant more efficient ink removal more efficient ink removal potential ink carryover,potential ink carryover,

improved washing, lowimproved washing, low over dispersion of ink,over dispersion of ink,

dose rates, independent dose rates, independent build up in water.build up in water.

of water hardness, of water hardness,

high brightnesshigh brightness


Advantages of Using Blended/Combinations of products

** Excellent ink removalExcellent ink removal

** Good washingGood washing

** Less deposition on PMLess deposition on PM

** Lower total chemical demand (e.g.. NaOH, Lower total chemical demand (e.g.. NaOH, H2O2 etc.)H2O2 etc.)

** Low dependence on water hardnessLow dependence on water hardness

** low dosages / cost effectivelow dosages / cost effective

** 100% liquid handling if required100% liquid handling if required

** On-site optimisation easyOn-site optimisation easy


De-inking Product DefinitionsDe-inking Product Definitions

Surfactant = Surface active AgentSurfactant = Surface active Agent

Associates with Ink, Dirt and Oil in the pulper. EffectivelyAssociates with Ink, Dirt and Oil in the pulper. Effectivelyacts as a cleaning agent to remove Ink from the fibre.acts as a cleaning agent to remove Ink from the fibre.

Reduces surface tension in stock to give more foam.Reduces surface tension in stock to give more foam.

Can be used to control foam in FlotationCan be used to control foam in Flotation


Fatty Acid/SoapFatty Acid/Soap = Collector chemical= Collector chemical

De-inking Product DefinitionsDe-inking Product Definitions

Liquid Fatty acid is neutralised in the pulper to produce Liquid Fatty acid is neutralised in the pulper to produce the sodium soap. Converted to Calcium Soap in flotation.the sodium soap. Converted to Calcium Soap in flotation.(Sometimes supplied as solid sodium soap)(Sometimes supplied as solid sodium soap)

Agglomerates ink particles freed in pulping and attachesAgglomerates ink particles freed in pulping and attachesthe ink to the bubbles that are removed in flotation.the ink to the bubbles that are removed in flotation.


COOHCH2 X2(CH )

CH2 X2(CH ) COONa

CH2 X2(CH ) COO

CH2 X2(CH ) COO

Ca

2 +Ca+

+ NaOH

INSOLUBLE

INSOLUBLE

SOLUBLE

SOLID

LIQUID

EMULSION

SOLUTION

IN SITUEMULSION

Fatty Acid Collector - MechanismFatty Acid Collector - Mechanism


Fatty Acid Soap - Collector MechanismFatty Acid Soap - Collector Mechanism

INK PARTICLESINK PARTICLES

+

SODIUMSODIUM STEARATESTEARATE

hydrophobic tailshydrophobic tails hydrophilic headshydrophilic heads

DISPERSED INKDISPERSED INK

Ca2+

NO HYDROPHILIC HEADSCOAGULATED INK

AIR BUBBLEAIR BUBBLE

+


De-inking Chemicals Selection ParametersDe-inking Chemicals Selection Parameters

The choice of chemicals depends on:-The choice of chemicals depends on:-

** Type of incoming furnish and process equipmentType of incoming furnish and process equipment

** Types of inks and binders used in these inksTypes of inks and binders used in these inks

** Amount of coatings presentAmount of coatings present

** Amount of Calcium available in the waterAmount of Calcium available in the water

** Operational conditions and final product specificationsOperational conditions and final product specifications


Mechanical Methods of Removing InksMechanical Methods of Removing Inks

Six Methods for removing or changing inks Six Methods for removing or changing inks and contaminantsand contaminants

WashingWashingFlotationFlotationCleanersCleanersScreensScreensKneading/DispersionKneading/DispersionClarificationClarification


WashingWashing

Most effective on inks 0 - 10 microns in size.Most effective on inks 0 - 10 microns in size.Washes away fine inks that flotation cannot Washes away fine inks that flotation cannot remove.remove.

Any thickening stage (disc filters, drum Any thickening stage (disc filters, drum thickeners etc) will help to wash fine inks out thickeners etc) will help to wash fine inks out of the systemof the system


Flotation Flotation

Most effective removal at particle sizes 15 - 100 Most effective removal at particle sizes 15 - 100 micronsmicrons

Air bubbles floated up through the fiber slurryAir bubbles floated up through the fiber slurryInk particles attach to the bubbles and are removedInk particles attach to the bubbles and are removed

Heterogenous bubbles are best for efficient in Heterogenous bubbles are best for efficient in removal (I.e. larger surface area for ink to attach to)removal (I.e. larger surface area for ink to attach to)



Typical Flotation PerformanceTypical Flotation Performance

ONP/OMGONP/OMGBrightness gainBrightness gain8 - 12 points typical8 - 12 points typical

Dependent upon:-Dependent upon:-Retention timeRetention timeOMG levelOMG levelConsistencyConsistency

Woodfree/MOWWoodfree/MOWInk removalInk removal85-95% typical85-95% typical

Dependent upon:-Dependent upon:-FurnishFurnishPulpingPulpingRetention timeRetention timeConsistencyConsistencyAddition pointAddition point


Kneader/DisperserKneader/Disperser

Reduces particle sizes of inks (Essential for Laser Reduces particle sizes of inks (Essential for Laser inks) to correct size for flotationinks) to correct size for flotation

Load on kneader determines particle reduction Load on kneader determines particle reduction efficiencyefficiency

Temperature is critical to performanceTemperature is critical to performance


Typical Performance MeasurementsTypical Performance Measurements

Image Analysis (Woodfree) - Image Analysis (Woodfree) - Dirt Count, speck Dirt Count, speck size distributionsize distribution

ERIC (ONP)ERIC (ONP) - - Effective ResidualEffective ResidualInk ConcentrationInk Concentration

BrightnessBrightness - - UV+, UV- (R457)UV+, UV- (R457)


IMAGE ANALYSISIMAGE ANALYSIS

Image analysis is used to determine the removal Image analysis is used to determine the removal efficiencies of a WF deinking plant. It measures ink efficiencies of a WF deinking plant. It measures ink specks in the visible range and is an excellent way specks in the visible range and is an excellent way of determining flotation and kneader/disperser of determining flotation and kneader/disperser efficiencies. efficiencies.


Commercial Deinking - Historical DevelopmentsCommercial Deinking - Historical Developments

1. Fatty Acid1. Fatty Acid Tallow based fatty acids have dominated the industryTallow based fatty acids have dominated the industry /Soaps/Soaps from the beginning and still maintain a strong positionfrom the beginning and still maintain a strong position

especially in Europe. (Stephensons, FINA, Eka, Nopco)especially in Europe. (Stephensons, FINA, Eka, Nopco)

2. Surfactants:-2. Surfactants:- Surfactant only systems were introduced in 1980 -1985Surfactant only systems were introduced in 1980 -1985These had limited success. Although dominant in JapanThese had limited success. Although dominant in Japanit was rejected in Europe and only had limited success init was rejected in Europe and only had limited success inNorth America.North America.

3. Fatty Acid/Surfactant Blends:-3. Fatty Acid/Surfactant Blends:-Blend technology was commercialised in 1990. ThereforeBlend technology was commercialised in 1990. ThereforeTallow FA’s were no longer dominant and were replaced byTallow FA’s were no longer dominant and were replaced byother fatty acid/surfactant combinations in North America.other fatty acid/surfactant combinations in North America.


Troubleshooting - FOAM Troubleshooting - FOAM Factors influencing foam productionFactors influencing foam production

1.1. pH.pH. OH from caustic stabilises foamOH from caustic stabilises foam

2.2. TemperatureTemperature Surfactants are temperature dependentSurfactants are temperature dependent

3.3. Ash contentAsh content The higher the ash content the higherThe higher the ash content the higherthe foam volume.the foam volume.

4.4. Furnish typeFurnish type Higher coating content gives more foamHigher coating content gives more foam

5.5. CalciumCalcium Typically need > 150ppm to get a good foamTypically need > 150ppm to get a good foamif using fatty acid/soapif using fatty acid/soap

6.6. De-inking agents Choice of product will determine foam levelDe-inking agents Choice of product will determine foam level


Troubleshooting - FoamTroubleshooting - Foam1. Too little foam1. Too little foam

a) Check pH. a) Check pH. Generally if pH is lower than 7.5 there will be Generally if pH is lower than 7.5 there will be little or no foam. An increase in caustic in pulper little or no foam. An increase in caustic in pulper or flotation will help to increase foam.or flotation will help to increase foam.

b) Check temp. b) Check temp. If the temperature is above the cloud point of theIf the temperature is above the cloud point of the surfactant being used then there will be no foam.surfactant being used then there will be no foam.

c) Check dosagec) Check dosageA small increase in de-inking chemical dosage willA small increase in de-inking chemical dosage willgive more foam (economically)give more foam (economically)

d) Furnishd) Furnish Low quantity or poor quality magazine content willLow quantity or poor quality magazine content willreduce foam volume. An increase in the amountreduce foam volume. An increase in the amountof magazine or office waste will increase foamof magazine or office waste will increase foam(expensive)(expensive)


Troubleshooting - FoamTroubleshooting - Foam1. Too much foam1. Too much foam

a) Check pH. a) Check pH. A reduction in caustic will help to reduce foamA reduction in caustic will help to reduce foamlevels.levels.

b) Check temp. b) Check temp. Increasing the temperature to slightly above the cloudIncreasing the temperature to slightly above the cloudpoint of the surfactant will help to reduce foam.point of the surfactant will help to reduce foam.

c) Check dosagec) Check dosageA decrease in de-inking chemical dosage willA decrease in de-inking chemical dosage willgive less foamgive less foam

d) Furnishd) Furnish Reduce level of magazine or office waste toReduce level of magazine or office waste toreduce foam.reduce foam.

e) Chemicallye) Chemically A small addition of a foam control agent can beA small addition of a foam control agent can beused economically to reduce foam. used economically to reduce foam.


Troubleshooting - QualityTroubleshooting - Quality

Brightness too lowBrightness too low Either the ink is not being removed inEither the ink is not being removed inpulping or not being collected in flotation.pulping or not being collected in flotation.

An increase in the level of surfactant will helpAn increase in the level of surfactant will helpto detach more ink from the fibre. However,to detach more ink from the fibre. However,the foam will need to be controlled.the foam will need to be controlled.

An increase in the fatty acid dosage will help toAn increase in the fatty acid dosage will help tocollect the ink better in flotation.collect the ink better in flotation.

NB.NB. Overdosing surfactant will result in dispersion of the ink into fine Overdosing surfactant will result in dispersion of the ink into fine particles which will not be removed in flotation and will remainparticles which will not be removed in flotation and will remainin the water system, causing quality problems (loss of brightness).in the water system, causing quality problems (loss of brightness).


Brightness too lowBrightness too low Overdosing caustic will lead to yellowingOverdosing caustic will lead to yellowingof the fibre and therefore lower brightness.of the fibre and therefore lower brightness.

Underdosing peroxide will lead to low bleachingUnderdosing peroxide will lead to low bleachingefficiency (caustic yellowing overrides the efficiency (caustic yellowing overrides the bleaching). Therefore lower brightness.bleaching). Therefore lower brightness.

Calcium content could be too low, therefore Calcium content could be too low, therefore decreasing efficiency of fatty acid collector.decreasing efficiency of fatty acid collector.Calcium Hydroxide or chloride can be addedCalcium Hydroxide or chloride can be addedto raise the level of calcium in system.to raise the level of calcium in system.

Increasing the office waste can also increaseIncreasing the office waste can also increasecalcium level. Plus background brightnesscalcium level. Plus background brightnessof furnish will be higher.of furnish will be higher.



Brightness too lowBrightness too low New products are available to increaseNew products are available to increasebleaching efficiency.bleaching efficiency.

Generally adjusting the chemicals is moreGenerally adjusting the chemicals is morecost effective than increasing the office wastecost effective than increasing the office wastefurnish.furnish.



Documents

De-inking Overview. What is Deinking? What is Deinking? The removal of ink from a fibre slurry by a combination of Chemical and Mechanical methods De-inking