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TiO2 Sulfate Process

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TiO2 Sulfate Process

Version: 190329

Page 2

General Process

Sulfate Process

(Base Material)

Post-Treatment

(TiO2 Pigment)

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TiO2 Sulfate Process

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Overview

H2SO4

Undigested

FinesOffgas

Copperas *

* If TiO2 slag is used crystallization isn’t necessary

Ore Digestion

and

Sedimentation

Crystallization

Hydrolysis

and Purification

of Hydrolysate

Doping and

Calcination

Offgas

Treatment

Offgas

Waste

Acid

Recycling

Base Material

to Post-

Treatment

Recycled

H2SO4

Ore,

TiO2 Slag

WasteBy-ProductEducts IntermediatesSymbols:

Overview

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TiO2 Sulfate Process

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Ore Digestion

Black Liquor

(TiOSO4, FeSO4, H2SO4)

with solids

Water

(H2O)

Ore Mill

Ilmenite, TiO2-Slag

Fuel

Air (Agitation)

Spent Acid (H2SO4) or

Recycled Acid (H2SO4)

Sulfuric Acid (H2SO4)

96-98%

Scrap Iron (Fe)

Burner

Air

to

Sedimentation

Overview

StackDigestion

Reactor

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TiO2 Sulfate Process

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Sedimentation

Polymer

Undigested

Fines

to Land Fill

Fine

Filtration

Filter Press

Black Liquor

(TiOSO4, FeSO4, H2SO4)

with solids

from

Ore Digestion

to

Crystallization

*Black Liquor

(TiOSO4, FeSO4, H2SO4)

to Hydrolysis

* If TiO2 slag is used then crystallization isn’t necessary

Overview

Sedimentation

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TiO2 Sulfate Process

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Crystallization *

Copperas (FeSO4 · 7 H2O)

(By-Product)Centrifugation

Crystallization

(Removing of water vapour by

using low pressure)

Black Liquor

(TiOSO4, FeSO4, H2SO4)from

Sedimentation

to HydrolysisBlack Liquor

(TiOSO4, FeSO4, H2SO4)

Overview

* If TiO2 slag is used crystallization isn’t necessary

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TiO2 Sulfate Process

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Hydrolysis

Steam

Diluted

Sulfuric Acid

Pre-Heater

from

Sedimentation

from

Crystallization

Steam

Caustic Soda

(NaOH)

To Pre-Leach-

and

Post-Leach-

Filtration

Impure Titanium Oxy

Hydrate

(TiO(OH)2, FeSO4 ,

H2SO4)

Black Liquor

(TiOSO4, FeSO4, H2SO4)

Overview

Hydrolysis

Seed

Production

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TiO2 Sulfate Process

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Pre-Leach- and Post-Leach-Filtration

Waste Acid

(H2SO4, FeSO4)

back to Process

Purified Titanium Oxy

Hydrate (TiO(OH)2)

Post-Leach Filtration

from Hydrolysis

Waste Acid

to

Waste Acid

Recycling

to

Doping

Water,

Diluted Sulfuric Acid

Water

Aluminum Powder,

Acid

Overview

Impure Titanium Oxy

Hydrate

(TiO(OH)2, FeSO4 ,

H2SO4)

Pre-Leach Filtration

Bleaching

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TiO2 Sulfate Process

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Doping

Filtrate

Doped Titanium Oxy

Hydrate (TiO(OH)2)

Filter Press

from

Post-Leach-

Filtration

Pure Titanium Oxy

Hydrate (TiO(OH)2)

Water (H2O),

Conditioning

Chemicals,

Rutile Seeds

to

Calcination

Overview

Doping

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TiO2 Sulfate Process

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Calcination

Fuel

from Doping

to

Offgas

Treatment

Base Material

(TiO2) to

Post Treatment

Overview

Dry Milling

Doped

Titanium

Oxy-

Hydrate

(TiO(OH)2)

Offgas

(TiO2, SO2, H2SO4-Mist)

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TiO2 Sulfate Process

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Waste Acid – Alternative 1

Sulfuric Acid Recycling

Metal Sulfate

(By-Product)

Waste Acid

(H2SO4, FeSO4)

Multi-Step Concentration

Metal Sulfate Separation

Recommended

Process

from

Pre-Leach-

Filtration

to

Ore Digestion

Overview

Concentration

Sulfuric Acid

(60-70%)

Sulfuric Acid

(75-95%)

Heller!

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TiO2 Sulfate Process

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Waste Acid – Alternative 2

Neutralization #1

Calcium Carbonate

(CaCO3)

Calcium Hydroxide

(Ca(OH) 2)

Waste Water

Gypsum,

Metal Hydroxides

to Land Fill

Filtration

Waste Acid

(H2SO4, FeSO4)

Overview

Neutralization

from

Pre-Leach-

Filtration

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TiO2 Sulfate Process

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Waste Acid – Alternative 3

Neutralization #2

Ammonium Sulfate

((NH4)2SO4)

By-Product

(Fertilizer)

Metal Hydroxides

to Land Fill

Ammonia

NH3

Waste Acid

(H2SO4, FeSO4)

Overview

Filtration

Neutralization

Evaporation

from

Pre-Leach-

FiltrationRemoving of

water vapour by

using low

pressure

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TiO2 Sulfate Process

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Offgas Treatment – Alternative 1

Titanium

Dioxide

(TiO2)

Iron (II)

Sulfate Solution

(FeSO4)

Sulfuric Acid

(H2SO4)

Offgas

(TiO2, SO2, H2SO4-Mist)

Scrubbing

Wet EGC

FeSO4, H2SO4(5-10%)

De-Dusting

from

Calcination

to

Ore Digestion

Recommended

Process

Overview

Stack

EGC = Electrical Gas Cleaning

Heller

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TiO2 Sulfate Process

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Offgas Treatment – Alternative 2

Demineralized

Water

(H2O)

Active Carbon Reactor

Pure H2SO4(10%)

Offgas

(TiO2, SO2, H2SO4-Mist)from

Calcination

Overview

Titanium

Dioxide

(TiO2)

De-Dusting

Sulfuric Acid

(H2SO4)

Wet EGC

Stack

EGC = Electrical Gas Cleaning

To

Pre-Leach-

Filtration

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TiO2 Sulfate Process

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Page 16

Advantages and Disadvantages

of Sulfate Process

compared to Chloride Process

▪ Larger buildings

▪ Lower product quality regarding optical and chemical properties

▪ In general, the production costs are higher, but it depends on the special circumstances

▪ More environmental impact due to more waste

▪ Process needs co-product management and attractive markets for co-products

▪ More man power necessary

▪ Lower requirements to equipments and automation

▪ Use of low grade ilmenite is possible.

▪ The process is less sensitive to production short-fall because there is no closed loop.

▪ Lower requirements to the qualification of the staff

▪ In case oleum is not used then lower safety requirements

ConsPros DisadvantagesAdvantages

Overview

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TiO2 Sulfate Process

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Raw Materials

Ilmenite/TiO2 slag

• Insoluble TiO2 residue should be below 1.5%

• Related to TiO2 the content of Cr2O3 shall be below 0.2%

• Low contents of CaO, SiO2,V2O5, Nb2O5, P2O5 are advantageous

• Low contents of radioactive elements are advantageous

Sulfuric acid:

• Technical quality is sufficient (concentration > 96%)

Overview