Review of Recovery & Disposal Methods for Three Major Types of Industrial Wastes in Jubail & Ras Al Khair

By: Dr. Mohamed Ismail and Dr. Maqbool AhmedERI – RC Environmental Consultant, Jubail.

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Understanding Three Major Industrial Wastes (Red Mud, Phosphogypsum and Gypsum)

Waste Characterization Current Status of Waste Handling Disposal methods (Worldwide) Recovery/Uses (Worldwide) Conclusions

Objectives

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1. RED MUD from Alumina Refinery, RIC Expected Generation : 2.65 Million Tons/Year

2. PHOSPHOGYPSUM from Phosphate Plant, RIC Expected Generation : 6.11 Million Tons/Year

3. GYPSUM from FGD process in JIC and RIC Expected Generation : 0.42 Million Tons/Year

Three major wastes from Ras Al Khair Industrial City (RIC) and Jubail Industrial

City (JIC)

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Bayer process (invented in 1887, by Austrian scientist Carl Josef Bayer) involves digestion of bauxite (an aluminum-containing ore) with sodium hydroxide (NaOH) at temperatures from 140 to 260 °C under high pressure (around 35 atm.) to produce Alumina (Al2O3). This process generates a highly alkaline (>13 pH) waste, called Bauxite Residue or Red Mud.

1. Red Mud (Bauxite Residue)

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Red mud in “as it is” state, solid concentration

~400g/l

Red mud after water

evaporation

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Typical Chemical Analysis of Bauxite Ore

Source: ATKINS FEED Report of RIC, 2012.

Component %

Aluminium Trioxide (Al2O3) 45-60

Iron Trioxide (Fe2O3) 2-9

Titanium Dioxide (TiO2) 3.5 (max)

Silicon Dioxide (SiO2) 2-9

Loss on Ignition (LOI) 27-30

Free Moisture 12 (max)

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Typical Chemical Analysis of Red Mud

Source: ATKINS FEED Report of RIC, 2012.

Component

% Component

%

Al2O3 14-20 V2O5 0-0.15

SiO2 10-12 ZnO 0-0.03

Fe2O3 45-60 MgO 0-0.06

TiO2 2-6 MnO 0-0.2

CaO 2-4 K2O 0-0.07

Na2O 5-8 LOI 7-12

P2O5 0.1-0.3

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In general, depending on the quality of Bauxite ore used, Red Mud generation varies from 0.3 tons/ton Alumina for high quality ore to 2.5 tons/ton Alumina for the lowest quality.

Red Mud will be generated in RIC as follows:

Red Mud in Ras Al Khair

Alumina Production

1.8 to 2.4 Million Tons/Year

Bauxite Ore4 to 9 Million

Tons/Year

Expected RED MUD Generation

~ 2.65 Million Tons/Year

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Typical Red Mud slurry contains 70-80% of water which is sent to settling or drying ponds which is a dominant practice until now. The free caustic soda left in waste stream needs to be neutralized before material in settling ponds can be removed for final disposal or reuse.

Current Status of Red Mud Handling around the World

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Factors to be considered for disposal techniques of Red Mud (containing 70 to 80% water):

• Reducing waste volume by dewatering• Neutralizing the mud • Assessing the potential reuse of dried residue • Minimizing the environmental impact.

In China, most of the Red Mud (RM) disposal is in landfill (Fei Peng et al).

In Japan, majority of RM is deposited into the ocean after neutralization.

Disposal of Red Mud around the World

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Based on Master Plan study for RIC, an onsite storage for Red Mud (termed “residue”) has been recommended. Accordingly, facility has designated a Red Mud storage area of approx. 800 Hectares which will be stored by “dry stacking” method.

At RIC, the red mud is first washed to remove as much alkaline materials as possible. After the residue is thickened to reduce water content, it is sent to the residue storage areas which act as drying beds to further reduce water content and reduce risks from leachate generation.

The current cells constructed for storage of Red Mud in RIC are fully lined by 1.5mm HDPE double liner by using International Best Practice design.

Storage of Red Mud Plan in RIC

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Possible Uses of Red Mud

Improving sandy (acidic) soils and add moisture holding capacity

Improve capacity to retain nutrients within soils to enhance agricultural capacities

Neutralizing acidic mine waste and gases Base material for road and embankment

construction Paving slab and building materials Recovering metal for further processing (iron,

titanium, rare earths) As a soil enhancing fertilizer to develop green

spaces for existing or new agricultural land.

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Uses of Red Mud around the World

Studies conducted on Red Mud (RM) reported several uses:

• As a pH modifier in the heap leaching of gold ores (R.E. Browner, 1992)

• As a pigment in anticorrosive marine paints (T. Skoulikidis et al, 1992)

In India, about 2.5 million tons were absorbed by the cement industry in 1998-99  (Hind et al).

In China, approximately 10% of RM produced is recycled for further metal extraction or utilized as a raw material for brick production (Fei Peng et al, Chemosphere).

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Neutralized red mud has been tested as a road base material in Kaiser Corporation in USA, China and Greece, and the compacted material showed resistance to erosion and proved to be stable under heavy roads.

In Australia the coarse portion of bauxite residue (“red sand”) is used as a road base for new road construction.

Chinese research shown silicate cement made from Red Mud is strong, sulfate and frost resistant, and a low cost alternative to Ordinary Portland Cement (OPC).

Uses of Red Mud around the World

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Building at Jamaica Bauxite Institute with bricks made from Red Mud

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Ras Al Khair will become one of the largest sites in world for production of phosphoric acid andphosphate fertilizers.

Phosphoric acid is produced by wet process, which involves digestion of phosphate rock in sulfuric acid.

Phosphate Rock + Sulfuric Acid Phosphoric Acid(Primary Product) + Phosphogypsum(By Product)

For every ton of phosphoric acid produced, up to 5 tons of Phosphogypsum waste may be created. (EU Commission, BAT document)

2. Phosphogypsum

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Chemical Analysis of various Phosphate Rocks around the World

Mass Fraction w(component

)/ %

CEI-Russi

a

South Africa-

Phalaborwa

Morocco- Khouribg

a

USA Florid

a

Senegal

KSA(Hazm

Al Jalamid

)

P2O5 38.9 36.8 33.4 34.3 36.7 29.35

CaO 50.5 52.1 50.6 49.8 50 51.78

SiO2 1.1 2.6 1.9 3.7 5.0 3.71

F 3.3 2.2 4.0 3.9 3.7 3.37

CO2 0.2 3.5 4.5 3.1 1.8 8.29

Al2O3 0.4 0.2 0.4 1.1 1.1 0.115

Fe2O3 0.3 0.3 0.2 1.1 0.9 0.074

MgO 0.1 1.1 0.3 0.3 0.1 0.279

Na2O 0.4 0.1 0.7 0.5 0.3 0.20

K2O 0.5 0.1 0.1 0.1 0.1 0.02

SO3 0.1 0.2 1.6 0.1 - 1.165

Cl - - 0.1 - - 0.053

SrO 2.9 0.3 0.1 - - -Ref: 1. N. Frankovic Mihelj et al., Waste Phosphogypsum – Toward Sustainable, Chem. Biochem. Eng. Q.27 (2013) 2. Phosphate Rock Analysis Data, Phosphate Plant, RIC

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Comparison of Major Chemical Compounds in Phosphogypsum at Croatian Fertilizer plant

PG1(Petrokemija tailing facility) and Ras Al Khair Facility PG2

Mass fractionW(component)/ %

PG1(July 2010)

PG 2(RIC, KSA)

Total P2O5 0.48 0.44

CaO 33.64 28.53

SO3 53.46 53.99

MgO 0.002 0.0185

SiO2 1.09 1.88

Ref: 1. N. Frankovic Mihelj et al., Waste Phosphogypsum – Toward Sustainable, Chem. Biochem. Eng. Q.27 (2013) 2. Phosphogypsum Analysis Data, Phosphate Plant, RIC.

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About 6.11 Million TPY of Phosphogypsum (PG) is expected from a facility in RIC.

The selected storage/disposal method is by Dry stacking along with leak-proof liner system, with stack height of 50m.

Facility has designated an area of approx. 650 Hectares for PG storage.

Current Status of Storage of Phosphogypsum in Ras Al Khair

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River Discharge• China (Yangtse)• France (Seine)• Romania (Danube)

Estuary Discharge• Netherland (mouth of Rhine, Rotterdam)• Spain (Confluence of the Tinto and Odiel Rivers, Huelva)

Sea Discharge• Tampa Bay, Florida (with little tidal movement)• Mediterranean Sea (Sfax, Tunisia, Tripoli, Lebanon)• North Sea (Immingham, UK)

Ocean• North Atlantic (Safi and Jorf Lasfar, Morrocco)

Past Methods of Disposal of Phosphogypsum around the World

Source: ATKINS FEED Report of RIC, 2012.

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Currently, above practice of discharge to water bodies is in rapid decline, due to following International Regulations which prohibits such activities:

• London Convention of International Maritime Organization (IMO)

• European Union Regulations

Currently, new plants around the world are designed not to discharge slurry material but operate closed loop production system contained on-site.

Current Practice of Handling Phosphogypsum around the World

Source: ATKINS FEED Report of RIC, 2012.

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Three common methods used to store PG are:

1. Dry Stacking (21 to 74m stack height in Florida, USA)

2. Wet Stacking (Brazil, China, Finland, USA, Spain, South Africa)

3. Back-fill to the mine

Current Methods of Phosphogypsum Storage/Disposal around the World

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AgricultureAs a fertilizer and soil conditioner for more than 50 crops including rice, wheat, fruits and vegetables.

Housing and ConstructionAs a raw material for cement, plasterboard, bricks, blocks, tiles and artificial stones.

RoadsAll weather and paved roads, embankment and fills.

Coastal and MarineFor building artificial reefs by using mixture of PG, fly ash & cement.

Uses of Phosphogypsum

Source: ATKINS FEED Report of RIC, 2012.

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Practice in USAMainly PG is kept stored by stacking method and has been allowed a limited use for agricultural purpose.

Practice in EuropeIn Europe, PG is used as a fertilizer, soil amendment, construction, wallboards and cement.

Other CountriesBrazil, China, India and South Africa are also recognizing the value of PG as a resource.

Uses of Phosphogypsum around the World

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Treatment of bauxite residue – a possible beneficial activity at RIC

Treatment of coal mine waste to remove barium and radium

Fertilizer binder Filler for plastic lumber Additive to red drilling mud to improve qualities Treatment of metal finishing wastes Removal of color and organics from textile waste Combination of red mud to enhance phosphate

retention in sandy soils De-icing additive

Experimental Uses of Phosphogypsum

Source: ATKINS FEED Report of RIC, 2012.

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FGD gypsum is a principal residue from steam generation units fitted with flue gas desulphurization (FGD) equipment. This is the product of the reaction between SO2 in the flue gases and hydrated lime used to separate it from the flue gases.

Approximately 0.42 Million TPY of gypsum is expected to be generated by Flue Gas Desulfurization process in the Steam generation units from Jubail and Ras Al Khair.

3. Gypsum

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Typical Chemical Composition of Gypsum from Jubail & RIC

Location Chemical Composition

Ras Al Khair CaSO4CaSO3CaCO3Fly AshMgCO3

91.93%0.34%2.58%4.53%0.63%

Jubail Calcium SulphateFree MoistureSodium SaltsCalcium Sulphite

>90% dry<10%<0.06%0.5%

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Possible Uses of Gypsum

Construction works Sealing material Cement manufacturing Fill for landscaping / land reclamation Fertilizer in agriculturee and forestry Raw material for aggregates, bricks and cement

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It is noted that Red Mud has various uses including brick manufacturing, as a pH modifier and in cement industries, etc.

For Phosphogypsum, there is a potential to use it for several purpose such as roads, construction works, agriculture, etc.

Regarding Gypsum, it is a valuable material to be used mainly for cement industries.

Conclusion

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Since, there is a great potential to reuse the above waste materials, we encourage the Investors to come forward to utilize the major waste materials produced in Ras Al Khair and Jubail namely Red Mud, Phosphogypsum, Gypsum and Fly Ash.

Conclusion

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Thank You