Phosphite ore deposits

Topic 10: PHOSPHITE ORE DEPOSITS
Prof. Dr. H.Z. Harraz Presentation Phosphate Deposits
2015- 2016
Hassan Z. Harraz
hharraz2006@yahoo.com

Outline of Topic 10:
We will explore all of the above in Topic 10.
 Phosphorite deposits
 Introduction
 Types of Phosphorite deposits
1) Igneous Phosphate Deposits
2) Biogenic (or Guano Bird ; or Island) Deposits
3) Marine Sedimentary Phosphate Deposits:
 Classification of Phosphatic Sedimentary Marine Rocks
 Depositional Environments
 Types of Sedimentary Phosphorite Deposition
 Nature and Occurrence
 Mineralogy and Mineral composition of phosphorite
deposit
 Origin of Phosphorite
 World Phosphate Rock Reserves and Resources
 Global Phosphate Rock Production
 Use of Phosphate

Introduction
 Phosphorite, phosphate rock or rock phosphate is a non-detrital sedimentary rock
which contains high amounts of phosphate bearing minerals.
 The phosphate content of phosphorite is at least 15 to 20%; if it is assumed that
the phosphate minerals in phosphorite are hydroxyapatite and fluoroapatite,
phosphate minerals contain roughly 18,5 % phosphorus by weight and if
phosphorite contains around 20% of these minerals, phosphorite is roughly 3,7 %
phosphorus by weight, which is a considerable enrichment over the typical
sedimentary rock content of less than 0.2%.
 Phosphorite deposits often occur in extensive layers, which cumulatively cover
tens of thousands of square kilometers of the Earth's crust.
 Limestones and mudstones are common phosphate bearing rocks. Phosphate rich
sedimentary rocks can occur in dark brown to black beds, ranging from centimeter
sized laminae to beds that are several meters in thickness. Although these thick
beds can exist they are rarely only composed of phosphatic sedimentary rocks.
Phosphatic sedimentary rocks are commonly accompanied by or interbedded with
shales, cherts, limestone, dolomites and sometimes sandstone. These layers
contain the same textures and structures as fine grained limestones and may
represent diagenetic replacements of carbonate minerals by phosphates. They also
can be composed of peloids, ooids, fossils, and clasts that are made up of apatite.
There are some phosphorites that are very small and have no distinctive granular
textures. This means that their textures are similar to that of collophane, or fine
micrite-like texture. Phosphatic grains may be accompanied by organic matter, clay
minerals, silt sized detrital grains, and pyrite. Peloidal or pelletal phosphorites
occur normally; whereas oolitic phosphorites are not common.
21 November 2015 Prof. Dr. H.Z. Harraz Presentation Phosphate Deposits 3

Introduction
Phosphate rock (PR) is a globally accepted but imprecise term describing any naturally occurring geological
material that contains one or more phosphate minerals suitable for commercial use. The term comprises both
the unprocessed phosphate ore as well as the concentrated phosphate products
Phosphorus is dissolved from the rocks, some of it enters the soil from which it is abstracted by
plants, from them passes into the bodies of animals, and is returned via their excreta and bones to
accumulate into deposits.
These in turn may undergo re-solution; reach the sea, and there the phosphorus deposited or
accumulated by sea life, embodied in sediments, and returned to the land upon uplift, when a new;
cycle may start.
Phosphates are soluble in carbonated water and, in the absence of calcium carbonate, will stay in
solution. The phosphate in limestones resists solution.
Some phosphoric acid in reaches the sea, where it is extracted by organisms; some is re-deposited
as secondary phosphates, which may be re-dissolved; and some is retained in the soil.
Swamp waters rich in organic matter also dissolve phosphates, and some phosphorus compounds
are thought to enter solution as colloids.
Phosphorus is probably transported by streams as phosphoric acid and as calcium phosphate
(some is transported by birds and animals).
Economic beds of phosphate are formed under marine conditions in the form of phosphorite.
The beds range in age from Cambrian to Pleistocene.
They are interstratified with other sediments and grade laterally into them.
Calcite and glauconite are usually found in the mineral paragenesis with phosphorite, occasionally
chlorite and siderite, and in the case of nodular deposits, also organic matter.

Types of Phosphorite Deposits:
 The various phosphate minerals present in Phosphate Rock (PR) have diverse
origins and chemical and physical properties.
 The phosphorus content or grade of phosphate rocks is commonly reported as
phosphorus pentoxide (P2O5). The principal phosphate minerals in PR are Ca-
phosphates, mainly apatites. Pure fluor-apatite contains 42% P2O5, and francolite,
the carbonate-substituted form of apatite, may contain 34% P2O5.
 Five major types of phosphate resources are being mined in the world:
1) Sedimentary Marine phosphate deposits,
2) Igneous phosphate deposits,
3) Metamorphic deposits,
4) Biogenic (or Guano Bird ; or Island) deposits,
5) Phosphate deposits as a result of weathering.
 Approximately 75% of the world’s phosphate resources are won from
sedimentary, marine phosphate rock deposits, 15-20% from igneous and
weathered deposits, and only 1-2% from biogenic resources, largely bird and bat
guano accumulations.
 The term ‘Phosphate Rock’ refers to rocks containing phosphate minerals,
usually apatite, which can be commercially exploited, either directly or after
processing, for commercial applications (Bartels & Gurr 1994).
 World production of phosphate rock in 2004 was 138 Mt (Jasinski 2005). The
USA, China and Morocco/western Sahara, North Africa, are the major producers
and are the source of about 60% of total global production.

Phosphate deposits are of three main types:
1) Igneous Phosphate Deposits
2) Biogenic (or Guano Bird ; or Island) Deposits
3) Marine Sedimentary Phosphate Deposits
Economic and potentially economic phosphate deposits of the world
www. Ifdc.org
Note:
Phosphate rocks of sedimentary origin
typically have 30-35% P2O5 whereas those
of igneous origin contain marginally higher
P2O5, typically 35 - 40%.

Igneous Phosphate deposits
1) Igneous Phosphate Deposits :
 Igneous intrusive alkali rocks, particularly
carbonatite complexes, and associated contact
metamorphic rocks, provide about 15–20% of the
world’s phosphate, usually as fluorapatite.
 Phosphate deposits are formed from alkaline
igneous rocks such as nepheline syenites,
carbonatites and associated rock types.
 The phosphate is, in this case, contained within
magmatic apatite, monazite or other rare-earth
phosphates.
 Igneous phosphate rock concentrates are
produced from deposits that are mainly exploited
in Russia, the Republic of South Africa, Brazil,
Finland and Zimbabwe.
 Igneous phosphate ores are often low in grade
(less than 5% P2O5), but can be upgraded to high-
grade products (from about 35 percent to over 40
% P2O5 ).
 Phosphate rocks of igneous origin contain
marginally higher P2O5, typically 35 - 40%.

2) Biogenic (or Guano Bird ; or Island) Deposits:
 These are ancient and/or fossil deposits of bird or bat excreta.
 Bird and bat excrement that has been leached to form an insoluble residue of calcium phosphate.
 Guano deposits from birds are most commonly found on oceanic islands, especially abundant- like some
South Pacific Islands.
 Guano deposits from bats are found in large cave systems.
 Guano deposits need a dry climate for their preservation.
 Accumulations of bird and mammal excrement have also provided important sources of
phosphate rock.
 Guano deposits on small oceanic islands, for example, Nauru and Christmas Island, were once
major sources of phosphate but are now declining in importance or have ceased production.
 At these localities, bird excrement has formed thick accumulations of calcium phosphate, or
guano, due to reaction of the organic waste with underlying limestone rocks.
Guano Mining in the Central Chinchua
Islands off the Central coast of Peru ~1860
The nest of the Peruvian Booby is made of almost pure guano.

3) Sedimentary Marine Phosphate Deposits
 Sedimentary Marine phosphate deposits occur on every continent and range in age from
Precambrian to Recent, although almost all exploited deposits are Phanerozoic in age. About 80%
of phosphate rock used commercially is obtained from marine sedimentary deposits
(phosphorites).
 Large resources of phosphates occur on the continental shelves and on seamounts in the Atlantic
and Pacific Oceans. They cannot be commercially mined, however, with current technology
(Jasinski 2005).
 Phosphorite beds consist of grains, pellets or fragments of cryptocrystalline apatite (collophane) and are
typically a few centimeters to tens of meters thick.
 These deposits typically show extensive reworking, secondary enrichment and replacement. Shallow
oceanic areas and continental shelves commonly have thick accumulations of phosphorus-rich organic
debris, mainly derived from deep oceanic sources associated with upwelling currents of cold, nutrient-rich
water. Sedimentary deposition of phosphate has occurred throughout much of the Earth’s history and
continues today.
Sedimentary Phosphorites

3) Sedimentary Marine Phosphate Deposits
 Sedimentary phosphorites are Organic/Chemical Sedimentary Rocks that contain more than 15% P2O5 or 6.5% phosphorus (P).
 are mined from rocks, usually shales, dolomite, or limestones, that contain unusually high concentrations of the mineral apatite
{Ca5(PO4)3(F, OH, Cl, ½ CO3)}. Sometimes it is mixed with enough calcite or clay to be limestone or shale.
 Sometimes, this is nearly pure apatite, in which case it is called “phosphorite” (i.e., Phosphorite is a commonly used term for
lithified phosphate rock).
 Immense quantities of phosphate rock or phosphorite occur in sedimentary shelf deposits, ranging in age from the Proterozoic to
currently forming environments.
 are commonly interbedded with marine shale, limestone, and dolomite.
 have textures that resemble limestones.
 may be made up of peloids, ooids, bioclasts and clasts that are now composed of apatite.
 Common names: Rock phosphate, phosphates
 Implies a marine origin
 Form in restricted areas near continental margins: where deep ocean currents are upwelling.
 Phosphorus is a limiting nutrient in many marine and fresh water ecosystems: limits primary productivity.
 Very little phosphorus is supplied to the oceans by river inflow.
 When phosphorus is supplied by upwelling from the deep ocean, productivity skyrockets.
 A rain of phosphate-rich skeletal debris falls to the ocean floor.
 Distinguished by chocolate brown color, may have pellets, lumps or nodules (mm scale)
 Marine deposits often have nodules.
 Deposits can be extensive (Ex: The Phosphoria Formation in Utah is phosphate-rich shale).
 Sedimentary phosphate deposits are of three main types:
a) Bone Beds (Bioclastic)
 Composed largely of vertebrate skeletal fragments.
 These are localized accumulations of fossil deposits of bone, teeth, scales and excreta (i.e. coprolites) that are occasionally thick enough to form economic deposits.
 These have mostly been mined in the past.
 A good example of bone beds is the marsupial-rich bone phosphate deposits of the Wellington Caves near Dubbo, New South Wales.
b) Nodular:
 Spherical to irregularly shaped nodules, with or without internal structure, often containing grain, pellets or fossils.
c) Pebble-bed:
 The sandstone equivalent-composed of nodules, fragments or phosphatic fossils that have been mechanically concentrated by reworking of earlier formed phosphate
deposits.
 All marine sediments, particularly limestones, contain some phosphate, which under particular conditions may rise to a greater concentration than
normal (phosphatic limestone), but rarely reaching an economically extractable concentration.
 These deposits are rare and usually arise from either the leaching of the phosphatic limestone (dissolving away the calcium carbonate and leaving
behind the detrital phosphate) or the extraction of phosphate at higher levels followed by secondary concentration from downward-percolating
groundwaters
 These deposits occur under relatively cool conditions in an oxygen-free environment.

Classification of Phosphatic Sedimentary Marine Rocks
(1) Pristine: Phosphates that are in pristine conditions have
not undergone bioturbation. In other words, the word
pristine is used when phosphatic sediment, phosphatized
stromatolites and phosphate hardgrounds have not been
disturbed.
(2) Condensed: Phosphatic particles, laminae and beds are
considered condensed when they have been
concentrated. This is helped by the extracting and
reworking processes of phosphatic particles or
bioturbation.
(3) Allochthonous: Phosphatic particles that were moved by
turbulent or gravity-driven flows and deposited by these
flows
21 November 2015
Prof. Dr. H.Z. Harraz
Presentation Phosphate 11

Fossiliferous peloidal phosphorite,
(4.7 cm across), Yunnan Province,
China.
Peloidal phosphorite, Phosphoria
Formation, Simplot Mine, Idaho. 4.6 cm
wide.

Depositional Environments
 Phosphates are known to be deposited in a wide range of depositional environments. Normally phosphates are deposited
in very shallow, near shore marine or low energy environments. This includes environments such as supratidal zones,
littoral or intertidal zones, and most importantly estuarine. Currently, areas of oceanic upwelling cause the formation of
phosphates. This is because of the constant stream of phosphate brought from the large, deep ocean reservoir . This cycle
allows continuous growth of organisms.
1) Supratidal zones: Supratidal environments are part of the tidal flat system where the presence of strong wave
activity is non-existent. Tidal flat systems are created along open coasts and relatively low wave energy
environments. They can also develop on high energy coasts behind barrier islands where they are sheltered from
the high energy wave action. Within the tidal flat system, the supratidal zone lies in a very high tide level. However,
it can be flooded by extreme tides and cut across by tidal channels. This is also subaerially exposed, but is flooded
twice a month by spring tides.
2) Littoral environments/ intertidal zones: Intertidal zones are also part of the tidal flat system. The intertidal zone is
located within the mean high and low tide levels. It is subject to tidal shifts, which means that it is subaerially
exposed once or twice a day. However, it is not exposed long enough to withhold vegetation. The zone contains
both suspension sedimentation and bed load.
3) Estuarine environments: Estuarine environments, or estuaries, are located at the lower parts of rivers that stream
into the open sea. Since they are in the seaward section of the downed valley system they receive sediment from
both marine and fluvial sources. These contain facies that are affected by tide and wave fluvial processes. From the
top, the estuary is considered to stretch from in the landward limit of tidal facies to the seaward limit of costal
facies. Phosphorites are often deposited in fjords within estuarine environments. These are estuaries with shallow
sill constrictions. During Holocene sea-level rise, these estuaries built a U-shaped valley profile formed by drowning
the glacially eroded valleys.
 The most common occurrence of phosphorites are related to strong marine upwelling of sediments. Upwelling is caused by
deep water currents that are brought up to coastal surfaces where a large deposition of phosphorites may occur. This type
of environment is the main reason why phosphorites are commonly associated with silica and chert. Estuaries are also
known as a phosphorus “trap”. This is because coastal estuaries contain a high productivity of phosphorus from marsh grass
and benthic alge which allow an equilibrium exchange between living and dead organisms.
Prof. Dr. H.Z. Harraz Presentation Phosphate Deposits 1321 November 2015

Types of Sedimentary Phosphorite Deposition
1) Phosphate nodules: These are spherical concentrations that are
randomly distributed along the floor of continental shelves. Most
phosphorite grains are sand size although particles greater than
2 mm may be present. These larger grains, referred to as nodules,
can range up to several tens of centimeters in size.
2) Bioclastic phosphates or bone beds: Bone beds are bedded
phosphate deposits that contain concentrations of small skeletal
particles and coprolites. Some also contain invertebrate fossils like
brachiopods and become more enriched in P2O5 after diagentic
processes have occurred. Bioclastic phosphates can also be
cemented by phosphate minerals.
3) Phosphatization: Phosphatization is a type of rare diagenetic
processes. It occurs when fluids that are rich in phosphate are
leached from guano. These are then concentrated and
reprecipitated in limestone. Phosphatized fossils or fragments of
original phosphatic shells are important components within some
these deposits.

Nature and Occurrence
• Different types of phosphate rocks have widely differing mineralogical, chemical and textural
characteristics.
• While there are more than 200 known phosphate minerals, the main mineral group of
phosphates is the group of apatites.
• Calcium-phosphates of the apatite group are mainly found in primary environments (in
sedimentary, metamorphic and igneous rocks) but also in weathering environments.
• Other phosphates include minerals of the crandallite group, as well as variscite and strengite,
which are Fe- and Al-containing phosphates principally found in secondary weathering
environments.
• Phosphorus occurs in many minerals, of which apatite {Ca5(F,Cl,OH)(PO4)3} is the most
abundant and by far the most important group. Characteristic minerals of the apatite group are
shown in Table 1
Table 1. Main apatite minerals (Source: Wallis (2004))
Mineral Description
Collophane Cryptocrystalline apatite
Francolite Carbonate fluorapatite with 5% carbonate and 1%
fluorine
Dahlite Carbonate hydroxyapatite with 5% carbonate and
2% hydroxide
Other phosphate-bearing minerals of potential economic significance include:
Monazite (Ce,La,Nd,Th)PO4
Turquoise CuAl6(PO4)4(OH)8.4H2O
Pyromorphite Pb5(PO4)3Cl.

Mineralogy and Mineral Composition of Phosphorite Deposits
The mineralogy of phosphate deposits is very complex.
They usually consist of fine-grained mixtures of various calcium phosphates with the most common
mineral being varieties of apatite and related minerals {Ca5(F,Cl,OH)(PO4)3}.
Collophane is an amorphous calcium phosphate that is also commonly found in phosphate deposits.
Mineral composition of phosphorite deposits: is determined by the phosphorite which is a composite
chemical compound of calcium phosphate, calcium fluoride, and calcium carbonate of the type of
nCa3(PO4)2.nCaF2.KCaCO3.
 Phosphate minerals occurring in the primary environment include:
1) Fluor-apatite {3Ca3(PO4)2CaF2 or Ca10(PO4)6F2} , found mainly in igneous and metamorphic
environments (for example, in carbonatites, and mica-pyroxenites), typically in
cryptocrystalline masses (grain sizes <1 μm) referred to as cellophane.
2) Carbonate-apatite or Carbonate-hydroxy-apatites {3Ca3(PO4)2CaCO3 or
(Ca10(PO4,CO3)6(OH)2)}, found mainly on islands and in caves, as part of bird and bat
excrements, guano,
3) Hydroxyl-apatite {3Ca3(PO4)2Ca(OH)2 or (Ca10(PO4)6(OH)2)}, found in igneous, metamorphic
environments but also in biogenic deposits, e.g. in bone deposits ; and
4) Francolite (Ca10-x-yNaxMgy(PO4)6-z(CO3)zF0.4zF2). This complex, carbonate-substituted apatite is
found mainly in marine environments, , which is often dissolved from vertebrate bones and
teeth, and, to a much smaller extent, also in weathering environments, for instance over
carbonatites.
Most are carbonate hydroxyl fluorapatites (a.k.a.: francolite) (Ca10(PO4,CO3)6F2-3) in which up to
10% carbonate ions can be substituted for phosphate ions.

Amblygonite Lazulite Pyromorphite Vivianite Torbernite
Autunite Xenotime Monazite Turquoise
Variscite Apatite Herderite Wavellite

 Phosphates form in shallow marine
environments where dissolved PO4
-3 is
carried by upwelling of deep ocean water.
 These areas are biologically productive -
many fossils are found, especially bone
material.
 Inhibition of organic mater decay due to
reducing conditions at ocean floor.
 Interstitial water exhalation
 Phosphatization: where phosphate replaces
skeletal and carbonate grains during
diagenesis.
Origin of Phosphorites
From Boggs, Principles of Sedimentology and Stratigraphy, 4th ed.,
p. 229
Phosphate accumulation is associated with oceanic
upwelling (cold, oxygen and nutrient rich bottom waters
coming to the surface, as happens off Peru). Under such
conditions, there is a great profusion of life, and consequently
death.
Organic remains (soft-body parts, bones, fecal matter)
sinks to the bottom.
The great abundance of incoming organic matter may
overwhelm the ability of bottom organisms to consume
this rain of food, and some goes undigested.
Under anaerobic conditions, the reduced organic matter
remains.
Under slightly more oxidizing conditions, the reduced
organic matter gets consumed, but the phosphate remains.
Under normal oxidizing conditions, the phosphate gets
consumed or dissolved into seawater.
Figure Schematic illustration of processes that form
phosphate deposits in the marine environment
Figure Schematic illustration of the formation of
Phosphorites in areas of upwelling on the open ocean
shelves.

Main features of a
simplified genetical model
for Egyptian phosphorites
From Boggs, Principles of Sedimentology and Stratigraphy, 4th ed.,
p. 229

Worldwide occurrence of phosphatic deposits
From Boggs, Principles of Sedimentology and Stratigraphy, 4th ed., p. 224

World Phosphate Rock Production and Demand-World Phosphate

Use of Phosphate
• About 90% of the phosphate produced is used in the manufacture of fertilizers, which are
available as a wide range of products. There are no known substitutes for the use of
phosphates as fertilizers.
• The remainder of world phosphate production is used in the manufacture of phosphoric
acid, phosphorus based industrial chemicals and phosphorus (Harben 1999). These are
mainly used in detergents, animal feed supplements, detergents, food and drink products,
fire extinguishers, dental products, and surface treatment of metals.
• In agriculture, phosphate is one of the three primary plant nutrients, and it is a component
of fertilizers. In former times, it was simply crushed and used as is, but the crude form is
now used only in organic farming. Normally, it is chemically treated to make Single
superphosphate (SSP), Triple superphosphate (TSP), or Mono-ammonium phosphates
(MAP) & Di-Ammonium Phosphates (DAP), which have higher concentration of phosphate
and are also more soluble, therefore more quickly usable by plants.
 Phosphate compounds are occasionally added to the public drinking water supply to
counter plumbo solvency.
 The food industry uses phosphates to perform several different functions ( For example, in
meat products, it solubilizes the protein). This improves its water-holding ability and
increases its moistness and succulence. In baked products, such as cookies and crackers,
phosphate compounds can act as part of the leavening system when it reacts with an
alkali, usually sodium bicarbonate (baking soda).
 Phosphate minerals are often used for control of rust and prevention of corrosion on
ferrous materials, applied with electrochemical conversion coatings
 Phosphoric acid and Chemical reagents

Most fertilizer manufacturing processes use Sulphuric
Acid, although some, mostly in Europe, use Nitric Acid.
Chemical grade phosphate rock should contain at least
24% P2O5, less than 3% Fe2O3 and have a CaO to P2O5
ratio between 3.3:1 and 3.6:1 (Holmes et al. 1982).
By-products from the use of phosphate rock include
gypsum, uranium, vanadium and fluorides (Bartels &
Gurr 1994). Much of the fluorine is evolved as gaseous
by-products during the manufacture of fertilizers.
The world’s phosphate rock deposits represent the
largest known resources of fluorine and could become
an increasingly important source of fluorine.
Use of Phosphate

Relationship of Phosphate Rock and
Phosphate Fertilizers
Single
Superphosphates
(SSP)
Triple
Superphosphates
(TSP)
Mono-Ammonium Phosphates
(MAP)
&
Di-Ammonium Phosphates (DAP)

 Phosphate is a relatively low unit-value commodity.
Therefore, most phosphate rock extraction operations tend
to involve surface mining, large-volume extraction and
reasonably low transport distances to major markets.
 In comparison to many other mineral commodities, the
demand for phosphate rock appears relatively predictable
and stable (Jasinski 2005). World fertilizers consumption
was predicted by the International Fertilizer Industry
Association to grow by 2.1% a year between 2003 and
2008, with phosphate consumption growing at a rate of
2.7% a year over the same period (Jasinski 2005). The
highest growth rates are likely to be in developing
countries, particularly in Asia and South America.
Economic Factors

Phosphate rock and fertilizer grade is almost universally expressed by those in this field as phosphate
pentoxide (P2O5). Most countries express the phosphorus
content of fertilizers as P2O5. This will be the convention of this report. Phosphate rock grade is often
listed in trade publications as BPL, referring to "bone phosphate of lime," the common name for
tricalcium phosphate.
Early workers believed tricalcium phosphate was the chief constituent of phosphate rock . These
commercial terms are widely used and the following conversion factors are included for reference
purposes:
P2O5 = 0.4576 x BPL
BPL = 2.1852 x P2O5
P = 0.1997 x BPL

1) A dragline scoops away
the overburden and digs out
the matrix that is equal
portions of sand, clay and
phosphate. The overburden is
later used in reclamation.
2) The matrix is dumped into
a pit where high-pressured
water guns create a slurry that
is pumped to the washer and
the beneficiation plant, often
miles away.
3) The washer and the
beneficiation process separate
the phosphate from the sand
and clay. The clay is sent to a
pond to settle. As it settles the
top clear water is recycled
back to the plant. The sand is
used in reclamation. The
phosphate is sent by train or
truck to a chemical plant.
4) At the chemical plant the phosphate is reacted with sulfuric acid to create the phosphoric acid that is
used in fertilizer and animal feed. A by-product of the chemical reaction is phosphogypsum, which is
stored in a stack near the plant.

At the chemical processing plant phosphate rock is reacted with sulfuric acid and
converted into the phosphoric acid used to make fertilizer.
Phosphogypsum, a by-product of the chemical processing, is stored in stacks.
It is pumped to ponds at the top of the stacks to settle.
Pond systems include collection areas at the foot of a stack for cooling the water
coming out of the plant.
All water is recycled for use in the plant.

The sulfuric acid that is needed to convert the phosphate rock into phosphoric acid is also produced
at the chemical processing plant, using liquid (molten) sulfur most of which is shipped and trucked to
the processing plants.
Since the energy crisis in the 1970s, most phosphate companies capture the heat released in the
burning of sulfur and production of sulfuric acid and use it to produce steam. The steam is used to
produce the heat required to concentrate the phosphoric acid and also to produce electricity to run
the plant. Typically, plants produce most of the energy they need and some sell a portion to the area
commercial energy provider.

Bartels J.J. & Gurr T.M. 1994. Phosphate rock. In: Carr D.D. ed. Industrial minerals and
rocks, 6th edition, pp. 751–764. Society for Mining, Metallurgy, and Exploration,
Inc., Littleton, Colorado.
Dominion Mining and Oil NL 1982. Exploration for phosphate in the southern
Eromanga Basin. Report on Exploration Licence Nos. 1685, 1686, 1687, 1688
Cobar. Geological Survey of New South Wales, File GS1982/265 (unpubl.).
Harben P.W. 1999. The industrial minerals handybook, 3rd edition. Industrial Minerals
Information Ltd, London. Harben P.W. & Kužvart M. 1996. Industrial minerals: a
global geology. Industrial Minerals Information Ltd, London.
Jasinski S.M. 2005. Phosphate rock. In: United States Geological Survey. compiler.
Mineral Commodity Summaries 2005, pp. 122–123. United States Department of
the Interior.
Schorr M. & Lin I.J. 1997. Wet process phosphoric acid production problems and
solutions. Industrial Minerals 355, 61–71.
Wallis D. 2004. Phosphate rock. NRM facts; mine series.
http://www.dpi.nsw.gov.au/minerals/geological/industrial-mineral-opportunities
References

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