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Gujarat Cleaner Production Centre
CLEANER PRODUCTION
OPPURTUNITIES
FERTILIZER MANUFACTURING
Gujarat Cleaner Production Centre – ENVIS CENTRE
CLEANER PRODUCTION
OPPURTUNITIES
IN
FERTILIZER MANUFACTURING
SECTOR
1 | P a g e
FERTILIZER MANUFACTURING
Gujarat Cleaner Production Centre
Introduction to Fertilizer Industry
India is the second biggest consumer of fertilizer in the world next only to China. The Indian
Fertilizer companies produced around 37.6 million
9% rise in comparison to 34.6 million
Sector-Wise, Nutrient-Wise Installed Capacity Of Fertilizer Manufacturing Units (As
31.03.2012.)
Fertilizers are materials used to provide plant nutrients which are deficient in soils.
industry is essentially concerned
phosphorus and potassium - in plant
form, N, but phosphorus and potash may be expressed either as the oxide (P2O5, K2O) or as the
element (P, K). Sulphur is also supplied in large amounts, partly through the sulphates present in
such products as superphosphate and ammonium sulphate
Nutrient content of common fertilizers
No. Material
1. Ammonium Nitrate
2. Ammonium Sulfate
3. Calcium Nitrate
4. Diammonium Phosphate
5. Monoammonium phosphate
6. Muriate of Potash
7. Potassium Nitrate
8. SKMG or SULPOMAG
Gujarat Cleaner Production Centre – ENVIS CENTRE
Introduction to Fertilizer Industry
India is the second biggest consumer of fertilizer in the world next only to China. The Indian
Fertilizer companies produced around 37.6 million tones of fertilizer in the year 2012
9% rise in comparison to 34.6 million tones of last year ( 2011-12 ) production.
Wise Installed Capacity Of Fertilizer Manufacturing Units (As
Fertilizers are materials used to provide plant nutrients which are deficient in soils.
industry is essentially concerned with the provision of three major plant nutrients
in plant-available forms. Nitrogen is expressed in the elemental
form, N, but phosphorus and potash may be expressed either as the oxide (P2O5, K2O) or as the
(P, K). Sulphur is also supplied in large amounts, partly through the sulphates present in
such products as superphosphate and ammonium sulphate
Nutrient content of common fertilizers
(%)
N P2O5 K2O MgO S
35 0 0 0 0
21 0 0 0 24
15.5 0 0 0 0
Diammonium Phosphate 18 46 0 0 0
Monoammonium phosphate 11 52 0 0 0
0 0 60 0 0
13.5 0 44 0 0
SKMG or SULPOMAG 0 0 22 18 22
2 | P a g e
India is the second biggest consumer of fertilizer in the world next only to China. The Indian
of fertilizer in the year 2012-13 with a
Wise Installed Capacity Of Fertilizer Manufacturing Units (As On
Fertilizers are materials used to provide plant nutrients which are deficient in soils. The fertilizer
with the provision of three major plant nutrients - nitrogen,
available forms. Nitrogen is expressed in the elemental
form, N, but phosphorus and potash may be expressed either as the oxide (P2O5, K2O) or as the
(P, K). Sulphur is also supplied in large amounts, partly through the sulphates present in
24
22
Gujarat Cleaner Production Centre
9. Sulphate of Potash
10. Single Super Phosphate
11. Triple Super Phosphate
12. Urea
Highlights of processes for different Fertilizers
(1) Urea
The first Haber Bosch plant was opened in 1913, and nitrogen production has been largely
dependent on ammonia synthesis ever since. Ammonia synthesis requires large amounts of
energy. Initially, this was provided by cheap electricity and derivatives of coa
or cryogenic separation of hydrogen from coke oven gas). These feedstocks were available only
in industrialized countries. Subsequently, more economic processes were developed which
involved the partial oxydation of hydrocarbons by pur
reforming of natural gas or naphta by steam.
Urea accounts for almost 50% of world nitrogen fertilizer production (in terms of N content, and
including multi-nutrient products), compared with only 30% a decade previously.
by combining ammonia and carbon dioxide at high pressure (140
(180-190°C) to form ammonium carbamate, which is then dehydrated by heat to form urea and
water, according to the following reaction:
(1) 2NH3 + CO2 → NH2COONH4
The first stage of the reaction is exothermic and proceeds to virt
conditions. The second stage is endothermic, and conversion is only partial (50
basis). The conversion is increased by i
and/or decreasing the H2O/CO2
ways to separate product urea from the
decompose the residual carbamate to NH3 and CO2 for recycling
There are three main types of process:
• . Once-through process: unconverted CO2 and NH3 are discharged to other plants, where
the NH3 is used for the production of fertilizers such as ammonium sulphate
ammonium nitrate
• Partial recycle process: unconverted CO2 and NH3 are partially separated in the
decomposition section of the first stage and are then recovered in an absorber, the
remainder being delivered to other plants as in the once
• Total recycle process: unconverted CO2 and NH3 are totally separated in multi
decomposers, recovered in corresponding multi
reactor.
Gujarat Cleaner Production Centre – ENVIS CENTRE
0 0 50 0 18
Single Super Phosphate 0 22 0 0 14
Triple Super Phosphate 0 46 0 0 0
46 0 0 0 0
different Fertilizers
The first Haber Bosch plant was opened in 1913, and nitrogen production has been largely
dependent on ammonia synthesis ever since. Ammonia synthesis requires large amounts of
energy. Initially, this was provided by cheap electricity and derivatives of coal (water gas process
or cryogenic separation of hydrogen from coke oven gas). These feedstocks were available only
in industrialized countries. Subsequently, more economic processes were developed which
involved the partial oxydation of hydrocarbons by pure oxygen and steam and the tubular
reforming of natural gas or naphta by steam.
Urea accounts for almost 50% of world nitrogen fertilizer production (in terms of N content, and
nutrient products), compared with only 30% a decade previously.
ammonia and carbon dioxide at high pressure (140-200 bar) and high temperature
ammonium carbamate, which is then dehydrated by heat to form urea and
water, according to the following reaction:
NH2COONH4 → CO(NH2) 2 + H2O
The first stage of the reaction is exothermic and proceeds to virtual completion under industrial
The second stage is endothermic, and conversion is only partial (50
increased by increasing the temperature, increasing the NH3/CO2 ratio
ratio. Process design is mainly concerned with the most efficient
ways to separate product urea from the other reaction components, to recover excess NH3
carbamate to NH3 and CO2 for recycling.
There are three main types of process:
through process: unconverted CO2 and NH3 are discharged to other plants, where
the NH3 is used for the production of fertilizers such as ammonium sulphate
Partial recycle process: unconverted CO2 and NH3 are partially separated in the
decomposition section of the first stage and are then recovered in an absorber, the
remainder being delivered to other plants as in the once-through process;
Total recycle process: unconverted CO2 and NH3 are totally separated in multi
decomposers, recovered in corresponding multi-stage absorbers, and recycled to the
3 | P a g e
18
14
The first Haber Bosch plant was opened in 1913, and nitrogen production has been largely
dependent on ammonia synthesis ever since. Ammonia synthesis requires large amounts of
l (water gas process
or cryogenic separation of hydrogen from coke oven gas). These feedstocks were available only
in industrialized countries. Subsequently, more economic processes were developed which
e oxygen and steam and the tubular
Urea accounts for almost 50% of world nitrogen fertilizer production (in terms of N content, and
nutrient products), compared with only 30% a decade previously. It is produced
200 bar) and high temperature
ammonium carbamate, which is then dehydrated by heat to form urea and
ual completion under industrial
The second stage is endothermic, and conversion is only partial (50-80%, CO2
ncreasing the temperature, increasing the NH3/CO2 ratio
ratio. Process design is mainly concerned with the most efficient
other reaction components, to recover excess NH3, and to
through process: unconverted CO2 and NH3 are discharged to other plants, where
the NH3 is used for the production of fertilizers such as ammonium sulphate and
Partial recycle process: unconverted CO2 and NH3 are partially separated in the
decomposition section of the first stage and are then recovered in an absorber, the
s;
Total recycle process: unconverted CO2 and NH3 are totally separated in multi-stage
rs, and recycled to the
Gujarat Cleaner Production Centre
(2) Urea-Ammonium Nitrate (U
UAN solutions provide a large share of the liquid fertilizer market. Concentrated urea and
ammonium nitrate solutions are measured, mixed and then cooled, and both continuous and
batch processes are available. A partial recycle CO2 stripping urea process m
unconverted NH3 and CO2 for conversion into UAN solutions. Typical input requirements per
tonne of UAN solution (30% N) are 328 kg urea, 426 kg ammonium nitrate, 245 kg water, and
steam/electricity equivalent to about 10 kWh. Corrosion inhi
protection, and there are normally traces of ammonia
(3) Ammonium Nitrate And Calcium Ammonium Nitrate
Ammonium nitrate (AN) and calcium ammonium nitrate (CAN) account for about 16% of world
nitrogen fertilizer production. They are particularly important in Europe and the FSU, which
account for about 75% of the world total. Ammonium nitrate is produced by n
acid with gaseous ammonia. The reaction is exothermic, producing AN solution and steam. In a
second stage, the AN solution is evaporated to the desired concentration, depending on whether
it will be finally prilled or granulated. CAN was
declared as dangerous goods (the AN content needs to be less than 80% AN). To produce CAN,
the AN solution is mixed with a filler containing dolomite, calcium carbonate, ground limestone
or, quite frequently, by-product calcium carbonate from a nitrophosphate plant (see below). This
mixture can also be either prilled or granulated. Ammonium sulphate nitrate (ASN) is another
mixture, produced by granulating AN and ammonium sulphate. The AN content needs to be less
than 45% to avoid dangerous good declaration.
Gujarat Cleaner Production Centre – ENVIS CENTRE
Ammonium Nitrate (UAN)
UAN solutions provide a large share of the liquid fertilizer market. Concentrated urea and
ammonium nitrate solutions are measured, mixed and then cooled, and both continuous and
batch processes are available. A partial recycle CO2 stripping urea process m
unconverted NH3 and CO2 for conversion into UAN solutions. Typical input requirements per
tonne of UAN solution (30% N) are 328 kg urea, 426 kg ammonium nitrate, 245 kg water, and
steam/electricity equivalent to about 10 kWh. Corrosion inhibitor may be added for equipment
protection, and there are normally traces of ammonia.
Ammonium Nitrate And Calcium Ammonium Nitrate
Ammonium nitrate (AN) and calcium ammonium nitrate (CAN) account for about 16% of world
nitrogen fertilizer production. They are particularly important in Europe and the FSU, which
account for about 75% of the world total. Ammonium nitrate is produced by n
acid with gaseous ammonia. The reaction is exothermic, producing AN solution and steam. In a
second stage, the AN solution is evaporated to the desired concentration, depending on whether
it will be finally prilled or granulated. CAN was developed to avoid the AN fertilizer being
declared as dangerous goods (the AN content needs to be less than 80% AN). To produce CAN,
the AN solution is mixed with a filler containing dolomite, calcium carbonate, ground limestone
product calcium carbonate from a nitrophosphate plant (see below). This
mixture can also be either prilled or granulated. Ammonium sulphate nitrate (ASN) is another
mixture, produced by granulating AN and ammonium sulphate. The AN content needs to be less
than 45% to avoid dangerous good declaration.
4 | P a g e
UAN solutions provide a large share of the liquid fertilizer market. Concentrated urea and
ammonium nitrate solutions are measured, mixed and then cooled, and both continuous and
batch processes are available. A partial recycle CO2 stripping urea process may also provide
unconverted NH3 and CO2 for conversion into UAN solutions. Typical input requirements per
tonne of UAN solution (30% N) are 328 kg urea, 426 kg ammonium nitrate, 245 kg water, and
bitor may be added for equipment
Ammonium nitrate (AN) and calcium ammonium nitrate (CAN) account for about 16% of world
nitrogen fertilizer production. They are particularly important in Europe and the FSU, which
account for about 75% of the world total. Ammonium nitrate is produced by neutralizing nitric
acid with gaseous ammonia. The reaction is exothermic, producing AN solution and steam. In a
second stage, the AN solution is evaporated to the desired concentration, depending on whether
developed to avoid the AN fertilizer being
declared as dangerous goods (the AN content needs to be less than 80% AN). To produce CAN,
the AN solution is mixed with a filler containing dolomite, calcium carbonate, ground limestone
product calcium carbonate from a nitrophosphate plant (see below). This
mixture can also be either prilled or granulated. Ammonium sulphate nitrate (ASN) is another
mixture, produced by granulating AN and ammonium sulphate. The AN content needs to be less
Gujarat Cleaner Production Centre
Fertilizer Production Routes
Gujarat Cleaner Production Centre – ENVIS CENTRE
Fertilizer Production Routes
5 | P a g e
Gujarat Cleaner Production Centre
(4) Single And Triple Superphosphate
Superphosphates account for over one quarter of world phosphate fertilizer production. Single
superphosphate (SSP) is produced by reacting mineral phosphate with sulphuric acid in
proportions which convert most of the phosphate to the water
Unlike the similar reaction which produces phosphoric acid, this process retains the calcium
sulphate in the product; and it is for this reason that SSP retains its importance wherever sulphur
deficiency limits crop yields. Triple superphosphat
produced by acidulating the mineral phosphate with phosphoric acid, instead of sulphuric acid.
Double, or enriched superphosphate is also produced, by using a mixture of the two acids. In all
cases, the emissions to air and water are similar to those involved in phosphoric acid production,
except for the problem of gypsum disposal in the latter case. Dust and fluorine removal from the
off-gases exiting the reactor/curing den is usually achieved with a venture scrubbi
involving a circulation solution of weak (less than 23 %) fluorosilicic acid. The venture scrubber
is equipped with a tail-gas scrubber in the form of a packed tower that is usually followed by an
entrainment separator. A modern system can reduce
emission to 0.3-1 kg/t of product.
There are always two stages in the manufacture of granulated single superphosphate, the first to
manufacture powdered single superphosphate and the second to granulate. Howeve
of triple superphosphate, there are two alternatives:
• .As in the case of single superphosphate, run
ROP material is prepared by reacting phosphate rock with phosphoric acid with a P2O5
concentration of 50 to 54%, but a lower concentration may be used, followed by
granulation.
• A slurry of phosphate rock reacted with phosphoric acid of 35% to 38% P2O5
concentration may be granulated directly in a traditional unit with a drum granulator,
drier etc.
(5) Multi-Nutrient Fertilizers
Large quantities of multi-nutrient fertilizers (NP/NPK/NK/PK) are produced simply by dry
mixing (or blending) single-nutrient materials without acidulation or chemical reaction. With
efficient management, such operations do not normally
emissions or wastes. Consequently,
multi-nutrient fertilizers, and these involve a
fall broadly into three groups:
• The mixed acid route,
• The phosphoric acid route,
• The nitric acid route.
Gujarat Cleaner Production Centre – ENVIS CENTRE
Single And Triple Superphosphate
Superphosphates account for over one quarter of world phosphate fertilizer production. Single
superphosphate (SSP) is produced by reacting mineral phosphate with sulphuric acid in
proportions which convert most of the phosphate to the water-soluble mono
Unlike the similar reaction which produces phosphoric acid, this process retains the calcium
sulphate in the product; and it is for this reason that SSP retains its importance wherever sulphur
deficiency limits crop yields. Triple superphosphate contains little sulphur, because it is
produced by acidulating the mineral phosphate with phosphoric acid, instead of sulphuric acid.
Double, or enriched superphosphate is also produced, by using a mixture of the two acids. In all
air and water are similar to those involved in phosphoric acid production,
except for the problem of gypsum disposal in the latter case. Dust and fluorine removal from the
gases exiting the reactor/curing den is usually achieved with a venture scrubbi
involving a circulation solution of weak (less than 23 %) fluorosilicic acid. The venture scrubber
gas scrubber in the form of a packed tower that is usually followed by an
entrainment separator. A modern system can reduce fluorine emission to 0.1 kg/t P2O5, and dust
1 kg/t of product.
There are always two stages in the manufacture of granulated single superphosphate, the first to
manufacture powdered single superphosphate and the second to granulate. Howeve
of triple superphosphate, there are two alternatives:
.As in the case of single superphosphate, run-of-pile (ROP) material may be used. The
ROP material is prepared by reacting phosphate rock with phosphoric acid with a P2O5
50 to 54%, but a lower concentration may be used, followed by
A slurry of phosphate rock reacted with phosphoric acid of 35% to 38% P2O5
concentration may be granulated directly in a traditional unit with a drum granulator,
utrient Fertilizers
nutrient fertilizers (NP/NPK/NK/PK) are produced simply by dry
nutrient materials without acidulation or chemical reaction. With
such operations do not normally give rise to significant environmental
emissions or wastes. Consequently, we are here concerned solely with chemically compounded
nutrient fertilizers, and these involve a wide variety of processes and formulations, which
The phosphoric acid route,
6 | P a g e
Superphosphates account for over one quarter of world phosphate fertilizer production. Single
superphosphate (SSP) is produced by reacting mineral phosphate with sulphuric acid in
soluble mono-calcium form.
Unlike the similar reaction which produces phosphoric acid, this process retains the calcium
sulphate in the product; and it is for this reason that SSP retains its importance wherever sulphur
e contains little sulphur, because it is
produced by acidulating the mineral phosphate with phosphoric acid, instead of sulphuric acid.
Double, or enriched superphosphate is also produced, by using a mixture of the two acids. In all
air and water are similar to those involved in phosphoric acid production,
except for the problem of gypsum disposal in the latter case. Dust and fluorine removal from the
gases exiting the reactor/curing den is usually achieved with a venture scrubbing system
involving a circulation solution of weak (less than 23 %) fluorosilicic acid. The venture scrubber
gas scrubber in the form of a packed tower that is usually followed by an
fluorine emission to 0.1 kg/t P2O5, and dust
There are always two stages in the manufacture of granulated single superphosphate, the first to
manufacture powdered single superphosphate and the second to granulate. However, in the case
pile (ROP) material may be used. The
ROP material is prepared by reacting phosphate rock with phosphoric acid with a P2O5
50 to 54%, but a lower concentration may be used, followed by
A slurry of phosphate rock reacted with phosphoric acid of 35% to 38% P2O5
concentration may be granulated directly in a traditional unit with a drum granulator,
nutrient fertilizers (NP/NPK/NK/PK) are produced simply by dry
nutrient materials without acidulation or chemical reaction. With
give rise to significant environmental
we are here concerned solely with chemically compounded
wide variety of processes and formulations, which
Gujarat Cleaner Production Centre
Environmental Issues in Fertilizer Industry and CP options
Cleaner Production means, “
environmental strategy to processes, products and services to increase eco
risks to humans and the environment
Cleaner Production activities with a focus on the actual manufacturing process itself and
considers the integration of better production systems to minimize environmental harm and
maximize production efficiency from many or all inputs.
Nitrogen Fertilizer Plants
(1) Urea
Cleaner production in Air Emission
• In the urea synthesis process, recover and recycle carbamate gases and/or liquids to the
reactor. Operate the top of the prilling
recovery and minimize air emissions by appropriate maintenance and operation of
scrubbers and baghouses.
• Use synthesis NH3 purge gas treatment to recover NH3 and H2 before combustion of the
remainder in the primary reformer.
• Increase the residence time for off
reformer;
• Ammonia emissions from relief valves or pressure control devices from vessels or
storages should be collected and
• Install leak detection methods to detect fugitive emissions of ammonia from process and
storage;
• Implement maintenance programs, particularly in stuffing boxes on valve stems and seals
on relief valves, to reduce or eliminate releases.
• Reduction of dust emissions by producing granular rather than prilled product;
• Installation of prilling towers with natural draft cooling instead of towers with
forced/induced draft air cooling;
• Scrubbing of off-gases with process condensate prior to discharge to atmospher
reprocessing the recovered urea solution;2
• Use of baghouse filters to prevent the emission of dust laden air from transfer points,
screens, bagging machines, etc., coupled with an urea dust dissolving system which
allows recycling of urea to the pro
• Flash melting of solid urea over
Cleaner production in Water Emission
Gujarat Cleaner Production Centre – ENVIS CENTRE
Environmental Issues in Fertilizer Industry and CP options
“the continuous application of an integrated, preventative
environmental strategy to processes, products and services to increase eco-efficiency and reduce
risks to humans and the environment”. Cleaner Technology may be “thought of a subset of
on activities with a focus on the actual manufacturing process itself and
considers the integration of better production systems to minimize environmental harm and
maximize production efficiency from many or all inputs.”
Air Emission
In the urea synthesis process, recover and recycle carbamate gases and/or liquids to the
reactor. Operate the top of the prilling tower at a slight vacuum. Maximize product
recovery and minimize air emissions by appropriate maintenance and operation of
scrubbers and baghouses.
Use synthesis NH3 purge gas treatment to recover NH3 and H2 before combustion of the
ry reformer.
Increase the residence time for off-gas in the high temperature zone of the primary
Ammonia emissions from relief valves or pressure control devices from vessels or
storages should be collected and Sent to a flare or to wet scrubber;
Install leak detection methods to detect fugitive emissions of ammonia from process and
Implement maintenance programs, particularly in stuffing boxes on valve stems and seals
on relief valves, to reduce or eliminate releases.
emissions by producing granular rather than prilled product;
Installation of prilling towers with natural draft cooling instead of towers with
forced/induced draft air cooling;
gases with process condensate prior to discharge to atmospher
reprocessing the recovered urea solution;2
Use of baghouse filters to prevent the emission of dust laden air from transfer points,
screens, bagging machines, etc., coupled with an urea dust dissolving system which
allows recycling of urea to the process;
Flash melting of solid urea over-size product which allows urea recycling to the process;
Water Emission
7 | P a g e
continuous application of an integrated, preventative
efficiency and reduce
thought of a subset of
on activities with a focus on the actual manufacturing process itself and
considers the integration of better production systems to minimize environmental harm and
In the urea synthesis process, recover and recycle carbamate gases and/or liquids to the
tower at a slight vacuum. Maximize product
recovery and minimize air emissions by appropriate maintenance and operation of
Use synthesis NH3 purge gas treatment to recover NH3 and H2 before combustion of the
gas in the high temperature zone of the primary
Ammonia emissions from relief valves or pressure control devices from vessels or
Install leak detection methods to detect fugitive emissions of ammonia from process and
Implement maintenance programs, particularly in stuffing boxes on valve stems and seals
emissions by producing granular rather than prilled product;
Installation of prilling towers with natural draft cooling instead of towers with
gases with process condensate prior to discharge to atmosphere, and
Use of baghouse filters to prevent the emission of dust laden air from transfer points,
screens, bagging machines, etc., coupled with an urea dust dissolving system which
size product which allows urea recycling to the process;
Gujarat Cleaner Production Centre
An urea plant generates a significant stream of process water containing NH3, CO2 and
urea (e.g., a 1,000 tons per day (t/
day (m3/d) of process water). Other sources are ejector steam, flush, and seal water.
Recommended pollution prevention and control measures include the following:
• Improve evaporation heater/se
• Remove NH3, CO2, and urea from the process water in a process water treatment unit,
and recycle the gases to the synthesis to optimize raw material utilization and reduce
effluents;
• Provide adequate storage capa
shutdown conditions
• Install submerged tanks to collect plant washings and other contaminated streams from
drains for recycling to process
Cleaner production in Solid waste
• Catalysts used in the process need to be disposed off after their activities are significantly
reduced. Normally, the catalyst used in the plant needs to be replaced at intervals of 5 to
7 years. These catalysts are normally
certain standard precautions and stored in closed containers. These spent catalysts have
ready market and are normally sold off, thus, as long as proper precautions are taken are
not likely to pose any environmen
spent catalysts become on unavoidable task not for lowering the catalysts cost but also for
reducing the catalysts waste to prevent the environmental pollution.
• Safe disposal of hazardous waste.
(2) Ammonium nitrate/ Calcium Ammonium Nitrate
Cleaner production in Air Emission
In ammonium nitrate plants the following pollution prevention measures are recommended:
• Install steam droplet separation techniques (e.g., knitted wire, mesh demister pads, wave
plate separators and fiber
pad separators using, for example, polytetrafluoroethylene (PTFE) fibers) or scrubbing
devices (e.g., packed columns, venturi scrubbers and irrigated sieve plates) to reduce
emissions of ammonia and ammonium nitrate in the steam
evaporators.10 A combination of droplet separators and scrubbers should be used to
remove ammonium nitrate particulate emissions. Nitric acid should be used to neutralize
any free ammonia;
• Treat and re-use contaminated condensate usin
or steam with the addition of alkali to liberate ionized ammonia if required, or use
distillation and membrane separation processes such as reverse osmosis;11
• Adopt the lowest practical melt temperature to reduce e
ammonium nitrate (and calcium carbonate in calcium ammonium nitrate (CAN)
production) from prilling and granulation emissions;
Gujarat Cleaner Production Centre – ENVIS CENTRE
An urea plant generates a significant stream of process water containing NH3, CO2 and
urea (e.g., a 1,000 tons per day (t/d) plant generates approximately 500 cubic meters per
day (m3/d) of process water). Other sources are ejector steam, flush, and seal water.
Recommended pollution prevention and control measures include the following:
Improve evaporation heater/separator design to minimize urea entrainment;
Remove NH3, CO2, and urea from the process water in a process water treatment unit,
and recycle the gases to the synthesis to optimize raw material utilization and reduce
Provide adequate storage capacity for plant inventory to prepare for plant upset and
Install submerged tanks to collect plant washings and other contaminated streams from
drains for recycling to process or conveying to the process water treatment unit.
Solid waste
Catalysts used in the process need to be disposed off after their activities are significantly
reduced. Normally, the catalyst used in the plant needs to be replaced at intervals of 5 to
7 years. These catalysts are normally pyrophoric and have to be removed by taking
standard precautions and stored in closed containers. These spent catalysts have
ready market and are normally sold off, thus, as long as proper precautions are taken are
not likely to pose any environment problem. The recovery of valuable elements from
spent catalysts become on unavoidable task not for lowering the catalysts cost but also for
reducing the catalysts waste to prevent the environmental pollution.
Safe disposal of hazardous waste.
/ Calcium Ammonium Nitrate
Cleaner production in Air Emission
In ammonium nitrate plants the following pollution prevention measures are recommended:
Install steam droplet separation techniques (e.g., knitted wire, mesh demister pads, wave
plate separators and fiber
pad separators using, for example, polytetrafluoroethylene (PTFE) fibers) or scrubbing
devices (e.g., packed columns, venturi scrubbers and irrigated sieve plates) to reduce
emissions of ammonia and ammonium nitrate in the steam from neutralizers and
evaporators.10 A combination of droplet separators and scrubbers should be used to
ammonium nitrate particulate emissions. Nitric acid should be used to neutralize
use contaminated condensate using techniques including stripping with air
or steam with the addition of alkali to liberate ionized ammonia if required, or use
distillation and membrane separation processes such as reverse osmosis;11
Adopt the lowest practical melt temperature to reduce emissions of ammonia and
ammonium nitrate (and calcium carbonate in calcium ammonium nitrate (CAN)
production) from prilling and granulation emissions;
8 | P a g e
An urea plant generates a significant stream of process water containing NH3, CO2 and
d) plant generates approximately 500 cubic meters per
day (m3/d) of process water). Other sources are ejector steam, flush, and seal water.
Recommended pollution prevention and control measures include the following:
parator design to minimize urea entrainment;
Remove NH3, CO2, and urea from the process water in a process water treatment unit,
and recycle the gases to the synthesis to optimize raw material utilization and reduce
city for plant inventory to prepare for plant upset and
Install submerged tanks to collect plant washings and other contaminated streams from
or conveying to the process water treatment unit.
Catalysts used in the process need to be disposed off after their activities are significantly
reduced. Normally, the catalyst used in the plant needs to be replaced at intervals of 5 to
pyrophoric and have to be removed by taking
standard precautions and stored in closed containers. These spent catalysts have
ready market and are normally sold off, thus, as long as proper precautions are taken are
t problem. The recovery of valuable elements from
spent catalysts become on unavoidable task not for lowering the catalysts cost but also for
In ammonium nitrate plants the following pollution prevention measures are recommended:
Install steam droplet separation techniques (e.g., knitted wire, mesh demister pads, wave
pad separators using, for example, polytetrafluoroethylene (PTFE) fibers) or scrubbing
devices (e.g., packed columns, venturi scrubbers and irrigated sieve plates) to reduce
from neutralizers and
evaporators.10 A combination of droplet separators and scrubbers should be used to
ammonium nitrate particulate emissions. Nitric acid should be used to neutralize
g techniques including stripping with air
or steam with the addition of alkali to liberate ionized ammonia if required, or use
distillation and membrane separation processes such as reverse osmosis;11
missions of ammonia and
ammonium nitrate (and calcium carbonate in calcium ammonium nitrate (CAN)
Gujarat Cleaner Production Centre
• In Prill tower, Reduce
entrainment.
• In Granulator reduce dust emissions from the disintegration of granules.
• For dusty products, use covers and hoods on
Handling
• Remove ammonia emissions from prilling and granulation by neutralization in a wet
scrubber. Wet scrubbers normally
wet scrubber will normally be recycled to the process;
• Remove ammonium nitrate fumes from prilling through scrubbing;
• Remove small particles of ammonium nitrate (miniprills), carried
through cyclones, bag filters and wet scrubbers;
• Adopt an enclosed granulation process instead of prilling technique where feasible;12
• Install an extraction, capture and filter system for ventilation air from areas with dust
generating product-handling activities to prevent fugitive
Cleaner production in Water Emission
Ammonium nitrate (AN) / calcium ammonium nitrate (CAN)
water to be treated for discharge
fertilizers production complex. Their process effluents typically include
containing up to 1percent ammonia and up to
(neutralizers) and evaporator boil
wash-down. Unabated emissions into water can be up to
2,500mg NH3 as N/l (6 and 3 kilograms
Pollution prevention and control measures for
• Internally recovery of ammonium nitrate and ammonia (e.g.
granulation plant air cleaning
stages on the granulation plant);
• Integrate AN/CAN plants
• Treat steam contaminated with ammonia or ammonium
droplet separation techniques and scrubbing devices · Treat process water (condensate)
by stripping with air or steam with the addition of alkal
needed; ion exchange; distillation; or
Cleaner production in Solid waste
• Solid wastes are principally spent catalysts that originate in ammonia production and in
the nitric acid plant. Other
Phosphate Fertilizer Plants
Cleaner production in Air Emission
• Maximize the recovery and recycling of dust from rock and product handling;
Gujarat Cleaner Production Centre – ENVIS CENTRE
Reduce micro prill formation & Reduce carryover of fines through
educe dust emissions from the disintegration of granules.
For dusty products, use covers and hoods on conveyors and transition points for Material
Remove ammonia emissions from prilling and granulation by neutralization in a wet
scrubbers normally use an acid circulating solution. The solution from a
wet scrubber will normally be recycled to the process;
Remove ammonium nitrate fumes from prilling through scrubbing;
Remove small particles of ammonium nitrate (miniprills), carried out with the air stream
through cyclones, bag filters and wet scrubbers;
Adopt an enclosed granulation process instead of prilling technique where feasible;12
Install an extraction, capture and filter system for ventilation air from areas with dust
handling activities to prevent fugitive emissions of particulates
Cleaner production in Water Emission
Ammonium nitrate (AN) / calcium ammonium nitrate (CAN) plants produce a sur
discharge or possibly recycled to other units in the nitrogenous
production complex. Their process effluents typically include
containing up to 1percent ammonia and up to 1percent ammonium nitrate from reactors
evaporator boil-off, and ammonium nitrate and nitric acid from
emissions into water can be up to 5,000mg AN as N/l and
2,500mg NH3 as N/l (6 and 3 kilograms per ton (kg/t) of product respectively).13
Pollution prevention and control measures for A/CAN plants include the following:
Internally recovery of ammonium nitrate and ammonia (e.g. scrubber liquor from the
granulation plant air cleaning section being recycled through the further evaporation
stages on the granulation plant);
Integrate AN/CAN plants with nitric acid production;
Treat steam contaminated with ammonia or ammonium nitrate, before condensation, by
techniques and scrubbing devices · Treat process water (condensate)
steam with the addition of alkali to liberate ionized
needed; ion exchange; distillation; or membrane separation processes.
Cleaner production in Solid waste
Solid wastes are principally spent catalysts that originate in ammonia production and in
the nitric acid plant. Other solid wastes are not normally of environmental concern.
Air Emission
Maximize the recovery and recycling of dust from rock and product handling;
9 | P a g e
Reduce carryover of fines through
conveyors and transition points for Material
Remove ammonia emissions from prilling and granulation by neutralization in a wet
use an acid circulating solution. The solution from a
out with the air stream
Adopt an enclosed granulation process instead of prilling technique where feasible;12
Install an extraction, capture and filter system for ventilation air from areas with dust-
particulates.
plants produce a surplus of
recycled to other units in the nitrogenous
production complex. Their process effluents typically include condensates
1percent ammonium nitrate from reactors
d ammonium nitrate and nitric acid from plant
5,000mg AN as N/l and
per ton (kg/t) of product respectively).13
include the following:
scrubber liquor from the
section being recycled through the further evaporation
nitrate, before condensation, by
techniques and scrubbing devices · Treat process water (condensate)
i to liberate ionized ammonia as
Solid wastes are principally spent catalysts that originate in ammonia production and in
solid wastes are not normally of environmental concern.
Maximize the recovery and recycling of dust from rock and product handling;
Gujarat Cleaner Production Centre
• Minimize the discharge of sulphur dioxide from sulphuric a
double contact double absorption process with high efficiency mist eliminators;
• Prevent spills and accidental discharges through well
installing spill catchment and containment facilities, and through
maintenance practices;
• Minimize the discharge of dust and fluorine from superphosphate plants to the
atmosphere by treating off
system.
• In the phosphoric acid plant, minimize
digester/reactor by scrubbers that are well
Again, design for spill containment
Maintain an operating water balance
• Where contamination of groundwater is a concern, a management and monitoring plan
should be implemented.
• Scrubbers are used to remove fluorides and acid from air emissions. The effluent from
the scrubbers is normally recycle
operating water balance in the phosphoric acid plant, then treatment to precipitate
fluorine, phosphorus, and heavy metals may be necessary. Lime can be used for
treatment. Spent vanadium catalyst is r
unavailable, then locked into a solidification matrix and disposed in a secure landfill
Cleaner production in Water Emission
• The discharge of sulfur dioxide from sulfuric acid plants should be minimized by using
the double-contact, double
Spills and accidental discharges should be prevented by using well
by installing spill catchment and containment facilities, and by practicing good
housekeeping and maintenance. Residues from the roasting of pyrites may be used by the
cement and steel manufacturing industries.
• Scrubbers are used to remove fluorides and acid from air emissions. The effluent from
the scrubbers is normally recycled to t
operating water balance in the phosphoric acid plant, treatment to precipitate fluorine,
phosphorus, and heavy metals may be necessary.
Cleaner production in Solid waste
• Lime can be used for treatment. Spe
recovery, or, if that cannot be
in a secure landfill.
• Opportunities to use gypsum wastes as a soil conditioner (for alkali soil and soils tha
deficient in sulfur) should be explored to minimize the volume of the gypsum stack.
• Consider the use of phosphor gypsum to produce gypsum board for the construction
industry.
Gujarat Cleaner Production Centre – ENVIS CENTRE
Minimize the discharge of sulphur dioxide from sulphuric acid plants by using the
double absorption process with high efficiency mist eliminators;
Prevent spills and accidental discharges through well bonded storage tanks, through
catchment and containment facilities, and through good housekeeping and
Minimize the discharge of dust and fluorine from superphosphate plants to the
treating off-gases using an efficient wet scrubbing/fluorine recovery
In the phosphoric acid plant, minimize emissions of fluorine compounds from the
scrubbers that are well-designed, well-operated, and well
Again, design for spill containment is essential to avoid inadvertent liquid discharges.
Maintain an operating water balance to avoid an effluent discharge.
Where contamination of groundwater is a concern, a management and monitoring plan
Scrubbers are used to remove fluorides and acid from air emissions. The effluent from
the scrubbers is normally recycled to the process. If it is not possible to maintain an
operating water balance in the phosphoric acid plant, then treatment to precipitate
fluorine, phosphorus, and heavy metals may be necessary. Lime can be used for
treatment. Spent vanadium catalyst is returned to the supplier for recovery or, if
unavailable, then locked into a solidification matrix and disposed in a secure landfill
Water Emission
The discharge of sulfur dioxide from sulfuric acid plants should be minimized by using
contact, double-absorption process, with high efficiency mist eliminators.
Spills and accidental discharges should be prevented by using well-bonded
by installing spill catchment and containment facilities, and by practicing good
housekeeping and maintenance. Residues from the roasting of pyrites may be used by the
cement and steel manufacturing industries.
Scrubbers are used to remove fluorides and acid from air emissions. The effluent from
the scrubbers is normally recycled to the process. If it is not possible to maintain an
operating water balance in the phosphoric acid plant, treatment to precipitate fluorine,
phosphorus, and heavy metals may be necessary.
Solid waste
Lime can be used for treatment. Spent vanadium catalyst is returned to the supplier for
recovery, or, if that cannot be done, it is locked in a solidification matrix and disposed of
Opportunities to use gypsum wastes as a soil conditioner (for alkali soil and soils tha
deficient in sulfur) should be explored to minimize the volume of the gypsum stack.
Consider the use of phosphor gypsum to produce gypsum board for the construction
10 | P a g e
cid plants by using the
double absorption process with high efficiency mist eliminators;
orage tanks, through
good housekeeping and
Minimize the discharge of dust and fluorine from superphosphate plants to the
gases using an efficient wet scrubbing/fluorine recovery
emissions of fluorine compounds from the
operated, and well-maintained.
is essential to avoid inadvertent liquid discharges.
Where contamination of groundwater is a concern, a management and monitoring plan
Scrubbers are used to remove fluorides and acid from air emissions. The effluent from
d to the process. If it is not possible to maintain an
operating water balance in the phosphoric acid plant, then treatment to precipitate
fluorine, phosphorus, and heavy metals may be necessary. Lime can be used for
eturned to the supplier for recovery or, if
unavailable, then locked into a solidification matrix and disposed in a secure landfill.
The discharge of sulfur dioxide from sulfuric acid plants should be minimized by using
absorption process, with high efficiency mist eliminators.
bonded storage tanks,
by installing spill catchment and containment facilities, and by practicing good
housekeeping and maintenance. Residues from the roasting of pyrites may be used by the
Scrubbers are used to remove fluorides and acid from air emissions. The effluent from
he process. If it is not possible to maintain an
operating water balance in the phosphoric acid plant, treatment to precipitate fluorine,
nt vanadium catalyst is returned to the supplier for
is locked in a solidification matrix and disposed of
Opportunities to use gypsum wastes as a soil conditioner (for alkali soil and soils that are
deficient in sulfur) should be explored to minimize the volume of the gypsum stack.
Consider the use of phosphor gypsum to produce gypsum board for the construction
Gujarat Cleaner Production Centre
• Design and operate phosphor gypsum disposal facilities to minimize impacts.
• Prepare and implement an emergency preparedness and response plan (required because
of the large quantities of sulfuric and phosphoric acids and other hazardous materials
stored and handled on the site).
• Consider providing pyrite
Mixed Fertilizer Plants
Cleaner production in Air Emission
This section addresses the production of ammonium phosphates (monoammonium phosphate
MAP, and diammonium phosphate
compound fertilizers.
• In the ammonium phosphate plant, pass the gas streams from the reactor, granulator,
dryer, and cooler through cyclones and scrubbers to recover particulates, ammonia, and
other materials for recycling.
• In the nitrophosphate plant, prevent NOx emissions by the addition of urea to the
digestion stage. Prevent fluoride emissions by scrubbing the gases with water. Remove
ammonia by scrubbing. Phosphoric acid may be used for scrubbing where the ammonia
load is high. Balance the p
• Additional pollution control devices beyond the scrubbers, cyclones and baghouses that
are an integral part of the plant design and operations are generally not required for
mixed fertilizer plants.
Cleaner production in Water Emission
• Good housekeeping practices are essential to minimize the amount of spilled material.
Spills or leaks of both solids and liquids should be returned to the process. Liquid
effluents, if any, need to be controlled for total suspended solids, fluorides, and
Cleaner production in Solid Waste
• There is no solid waste except sand which can be used as a building material after
washing and separation.
• By-products are converted into commercial products and spillages and off
products are recycled into the NPK production.
Problems with Superphosphate
1. Depletion of the soil traces
2. This occurs for at least two reasons:
a) The increased yield of acreage or tonnage of crops means that more trace elements go
into the crops, and these trace minerals are then removed from the soil when the crop is
harvested.
b) Superphosphates seem to speed up the oxidation rate of the plants, we
microorganisms.
c) Other damage to the soil micro
3. Topsoil erosion.
Gujarat Cleaner Production Centre – ENVIS CENTRE
Design and operate phosphor gypsum disposal facilities to minimize impacts.
Prepare and implement an emergency preparedness and response plan (required because
of the large quantities of sulfuric and phosphoric acids and other hazardous materials
stored and handled on the site).
Consider providing pyrite-roasting residues to the cement or steel-making industry.
Cleaner production in Air Emission
This section addresses the production of ammonium phosphates (monoammonium phosphate
diammonium phosphate-DAP), nitrophosphates, potash (potassium chloride
In the ammonium phosphate plant, pass the gas streams from the reactor, granulator,
dryer, and cooler through cyclones and scrubbers to recover particulates, ammonia, and
other materials for recycling.
plant, prevent NOx emissions by the addition of urea to the
digestion stage. Prevent fluoride emissions by scrubbing the gases with water. Remove
ammonia by scrubbing. Phosphoric acid may be used for scrubbing where the ammonia
load is high. Balance the process water system to avoid the discharge of an effluent.
Additional pollution control devices beyond the scrubbers, cyclones and baghouses that
are an integral part of the plant design and operations are generally not required for
Emission
Good housekeeping practices are essential to minimize the amount of spilled material.
Spills or leaks of both solids and liquids should be returned to the process. Liquid
effluents, if any, need to be controlled for total suspended solids, fluorides, and
Solid Waste
There is no solid waste except sand which can be used as a building material after
products are converted into commercial products and spillages and off
d into the NPK production.
Superphosphate or N-P-K Fertilization of the Soil
traces minerals.
This occurs for at least two reasons:
increased yield of acreage or tonnage of crops means that more trace elements go
into the crops, and these trace minerals are then removed from the soil when the crop is
Superphosphates seem to speed up the oxidation rate of the plants, we
c) Other damage to the soil micro-organisms.
11 | P a g e
Design and operate phosphor gypsum disposal facilities to minimize impacts.
Prepare and implement an emergency preparedness and response plan (required because
of the large quantities of sulfuric and phosphoric acids and other hazardous materials
making industry.
This section addresses the production of ammonium phosphates (monoammonium phosphate-
DAP), nitrophosphates, potash (potassium chloride), and
In the ammonium phosphate plant, pass the gas streams from the reactor, granulator,
dryer, and cooler through cyclones and scrubbers to recover particulates, ammonia, and
plant, prevent NOx emissions by the addition of urea to the
digestion stage. Prevent fluoride emissions by scrubbing the gases with water. Remove
ammonia by scrubbing. Phosphoric acid may be used for scrubbing where the ammonia
rocess water system to avoid the discharge of an effluent.
Additional pollution control devices beyond the scrubbers, cyclones and baghouses that
are an integral part of the plant design and operations are generally not required for
Good housekeeping practices are essential to minimize the amount of spilled material.
Spills or leaks of both solids and liquids should be returned to the process. Liquid
effluents, if any, need to be controlled for total suspended solids, fluorides, and ammonia
There is no solid waste except sand which can be used as a building material after
products are converted into commercial products and spillages and off-specification
increased yield of acreage or tonnage of crops means that more trace elements go
into the crops, and these trace minerals are then removed from the soil when the crop is
Superphosphates seem to speed up the oxidation rate of the plants, weeds, and the soil
Gujarat Cleaner Production Centre
4. Reduced soil permeability.
5. More severe poisoning of the soil, plants, animals, humans and the environment with
newer toxic pesticides and insecticides.
6. Reduced general soil fertility.
7. More toxic metals in the soil
Bibliography
1. The Fertilizer Industry's Manufacturing Processes and Environmental Issues
2. Reference Document on Best Available Techniques for the Manufacture of
Volume Inorganic Chemicals
3. Death in the Air: Air Pollution from Phosphate Fertilizer Production
4. Environmental, Health, and Safety Guidelines
5. Pollution Prevention and Ab
1998
6. Project Profile : NPK Fertilizers by APTICO ltd.
7. Fertilizer Mixing Plant Feasibility Study
Development (AID-SI] -165T)
8. India’s Fertilizer Industry:
9. Productivity and Energy Efficiency by Katja Schumacher and Jayant Sathaye
10. Competition Assessment Of Fertilizer Sector: India,Submitted to Competition
Commission of India Under the Guidance of Mrs. Renuka Jain Gupta , 2011
11. Supply of and access to key nutrients NPK for fertilizers for feeding the world in 2050 by
Maria B LANCO, Final version: 2011
12. Best Available Techniques for Pollution Prevention and Control in the European
Fertilizer Industry Booklet No. 7 of 8: Production Of
Nitrophosphate Route,2000 EFMA (European Fertilizer Manufacturers’ Association)
13. Important questions on fertilizer and the environment by YARA
14. Impact Assessment of Fertilizer Industry Waste on Environment by R.P. Prajapati*and
Rashmi Singhai , Journal of Environmental Science, Computer Science and Engineering
& Technology
15. Best Available Techniques for Pollution Prevention and Control in the European
Fertilizer Industry Booklet No. 6 of 8: Production Of Ammonium Nitrate And Calcium
Ammonium Nitrate, 2000 EFMA (European Fertilizer Manufacturers’ Association
Website
1. http://fert.nic.in/sites/default/files/Annual_Report2012
2. file:///E:/ENVIS/S_R%2029%20%20Air%20Pollution%20from%20Phosphate%20Fertili
zer%20Production%20%28George%20
3. http://www.drlwilson.com/ARTICLES/SUPERPHOSPHATES.htm
Gujarat Cleaner Production Centre – ENVIS CENTRE
Reduced soil permeability.
More severe poisoning of the soil, plants, animals, humans and the environment with
newer toxic pesticides and insecticides.
Reduced general soil fertility.
More toxic metals in the soil
The Fertilizer Industry's Manufacturing Processes and Environmental Issues
Reference Document on Best Available Techniques for the Manufacture of
Volume Inorganic Chemicals- Ammonia, Acids and Fertilizers ,August 2007
Death in the Air: Air Pollution from Phosphate Fertilizer Production by George Glasser
Environmental, Health, and Safety Guidelines Nitrogenous Fertilizers
Pollution Prevention and Abatement Handbook WORLD BANK GROUP Effective July
Project Profile : NPK Fertilizers by APTICO ltd.
Fertilizer Mixing Plant Feasibility Study Prepared for Agency for International
165T) by N. Terry Frederick and Robert T. Smith
India’s Fertilizer Industry:
Productivity and Energy Efficiency by Katja Schumacher and Jayant Sathaye
Competition Assessment Of Fertilizer Sector: India,Submitted to Competition
Commission of India Under the Guidance of Mrs. Renuka Jain Gupta , 2011
ly of and access to key nutrients NPK for fertilizers for feeding the world in 2050 by
Maria B LANCO, Final version: 2011
Best Available Techniques for Pollution Prevention and Control in the European
Fertilizer Industry Booklet No. 7 of 8: Production Of NPK Fertilizers By The
2000 EFMA (European Fertilizer Manufacturers’ Association)
Important questions on fertilizer and the environment by YARA
Impact Assessment of Fertilizer Industry Waste on Environment by R.P. Prajapati*and
Singhai , Journal of Environmental Science, Computer Science and Engineering
Best Available Techniques for Pollution Prevention and Control in the European
Fertilizer Industry Booklet No. 6 of 8: Production Of Ammonium Nitrate And Calcium
, 2000 EFMA (European Fertilizer Manufacturers’ Association
http://fert.nic.in/sites/default/files/Annual_Report2012-13.pdf
file:///E:/ENVIS/S_R%2029%20%20Air%20Pollution%20from%20Phosphate%20Fertili
zer%20Production%20%28George%20Glasser%29.htm
http://www.drlwilson.com/ARTICLES/SUPERPHOSPHATES.htm
12 | P a g e
More severe poisoning of the soil, plants, animals, humans and the environment with
The Fertilizer Industry's Manufacturing Processes and Environmental Issues
Reference Document on Best Available Techniques for the Manufacture of Large
,August 2007
by George Glasser
atement Handbook WORLD BANK GROUP Effective July
Prepared for Agency for International
by N. Terry Frederick and Robert T. Smith
Productivity and Energy Efficiency by Katja Schumacher and Jayant Sathaye
Competition Assessment Of Fertilizer Sector: India,Submitted to Competition
Commission of India Under the Guidance of Mrs. Renuka Jain Gupta , 2011
ly of and access to key nutrients NPK for fertilizers for feeding the world in 2050 by
Best Available Techniques for Pollution Prevention and Control in the European
Fertilizers By The
2000 EFMA (European Fertilizer Manufacturers’ Association)
Impact Assessment of Fertilizer Industry Waste on Environment by R.P. Prajapati*and
Singhai , Journal of Environmental Science, Computer Science and Engineering
Best Available Techniques for Pollution Prevention and Control in the European
Fertilizer Industry Booklet No. 6 of 8: Production Of Ammonium Nitrate And Calcium
, 2000 EFMA (European Fertilizer Manufacturers’ Association)
file:///E:/ENVIS/S_R%2029%20%20Air%20Pollution%20from%20Phosphate%20Fertili