About project
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Potash Exploration and Equipping Project
is a national project and works under authority of IRAN Mineral
production and supply Company.The playa of Khor with an
extension of 2000 km2 is in the Central Kavir of Iran near, the
khor city is located in about 310 km east of Naien,and 40 km
Khor in north of the way Khor-Tabas.
Potash exploration and equipping project is being mobilized with
the aim of producing 50000 MT KCl, 300000 MT NaCl and 30000 MT
Mg(OH)2 annually.
Exploration studies of the playa are done in an extension of
2000 km2 in 1998 by Tousehe Olum Zamin consulting engineers.
Taking in
account the porosity of the salt crust, volume of brine reserve is about
450 Mm3. This brine contains of Na, K, Mg, Ca, and small amount of SO4
ions and no I and Br has been detected.To produce yearly 50000 MT KCl
from this brine, about 13 km2 solar ponds are built which 1/3 of them
are carnalite ponds and 2/3 are salt ponds.Two pipelines with diameter
of 70 cm are erected in order to transfer brine with maximum capacity of
4000 m3 in hour to the solar ponds.Providing brine from different parts
of the playa is done by means of seapage channels and several excavated
wells.Precipitation of salt and carnalite in the solar ponds will done
in separate phases and will be controlled by growing density came from
evaporation procedure. The final brine is sent out from carnalite ponds
and is brought back to playa again. The salt and carnalite which are
settled down in the ponds are transferred to plant after harvesting.
Part of the removed salt is washed at salt-washing plant with the
capacity of 300000 annually. All the process has been checked by pilot
tests in pilot plants in site. The main building of project is located
in Khor city which contains offices, laboratories, and uesthouse. The
pilot plant, meteorology station and researching ponds are also
there.Also 6-mega watt electricity for revenue of manufacturing unites
and pumping station is just installed as a power plant and this amount
of electricity is now provided by 4 Diesel generators with capacity of
1.5-mega watt each one. By putting in to operation the plant 400 persons
directly and 1000 persons indirectly will work at this project, so these
employment will create a great change in the area of Khor and Biabanak.
Prospecting
Potash Exploration Project, has began with prospecting of Brines and
Potash- Salt rocks in several parts of IRAN such as Kashan playa, Qom,
Hozesoltan, Varzaneh, Degh Sorkh Ardestan, Loot Zangi Ahmad, Khor playa,
Sirvan, Rahrahak and Pohl Salt Dom. After primary studies and comparing
the results Khor & Biabanak playa has been selected as the first choice
for production of Potash. The work has been managed for the stages of
exploration in three part of the playa, Southern, Middle and Northern
area
Geological conditions
In the central part of Great Kavir, there is a Drainage Basin that playa
of Khor part of it. Although the Basin is the lowest part, the Khor
playa location is on a plateau 600-850 above sea level.37 percent of
Great Kavir is a Miu-pliocen sedimentary environment that deep impressed
erosion shaped it as a flat field. Depression parts of this field on
marl and evaporates formed the small & large playa and the other parts
are covered by Alluvial fan and sand hills.
Playa
Great Kavir playa basin can be divided to three separate parts. Suothern
basin with an extension of 2000 km2 is near Khor city and it is named "
Playa of Khor". This Playa from center to borders can be saperate to
three zones: Salt crust, Moistural zone and clay pan.Taking in account
the prosity of the salt crust volume of brine reserve is about 450
million cubic meters. This brine contains of Na, K, Mg, Ca, No3 and
small amount of SO4 ions. No I and Br has been detected.
Climate
The climatic conditions at plant location are
characterized by the following average values:
Minimum temperature: average 15C, below 0 C is possible in
the
month December, January, February
Maximum temperature: average > 40C, not below 15C in the
month July, August, September
Annual rainfall: 82 liters per m2
Annual sunshine duration: 3300 hours per year
Annual evaporation rate: 2900 liters per m2
Air humidity: minimum in July 19%,
maximum in January 53%
Wind velocity: average 5.6 km/h
maximum 67 km/h
Collection Channels
The Brine collection is done in open channel network and Brine wells.
The area of the channel is 16 m2 and their total length is about
26 km. The Brine wells will be excavated deeper
than the channels. The lower parts of Brine are much more reached of
Mg-Ca-K than the upper parts. So for a better quality of brine it's
needed to use these wells.
For each well in depth of 10-13 m there will be a pump and the brine
will transmit to the channels with concrete and PVC channels. The
collected brine is to tansmit to the solar ponds from the pump station
via two 8.8 km GFRP pipeline with 700 mm diameter each one.main pump
station is located in the North of Khor- Tabas road with the max.
capacity of 4000 m3 per hour. At the end of pipeline is a plunge pool to
adjustment of the ponds.8 electro pump will work in an area about 725
m2.
channel Ý
pipe line Ý
Solar Ponds
High evaporation
rate in Kavir region and poor annual rainfalls are two reasons to use
solar ponds for precepitation of salt and carnallite, these two pand
products are the main feeds of potash and salt plants. The ponds have
designed considering plant mass ballance for production of 5000 tph
potash, sea page pert in floors and walls, evaporation rate, annual
rainfalls, brine pump age perts in pumps and pipe juctions, ect. and
finally evaporation pilot tests. There are 8 salt ponds and 6 carnallite
ponds13 km2 total area. The brine with a density of 1.218-1.223 and with
maximum rate of 4000 m3/h in warm seasons will come from playa to ponds
via GFRP pipeline and rocky channels around the ponds.
Evaporation procedure increases the density and decreases the Na content
by precipitation of NaCl in salt ponds. When the density reach to
1.340-1.360 the precipitation of carnallite begins and in the end of
evaporation process the remaining brine has a density of 1.450 and a
high calcium, Magnesium, Nitrate and chloride content. This remaining
heavy brine must be back to playa .
The extraction of salt and carnallite from the ponds will be done via
heavy machines named Harvesters. The mechanism is very similar to cold
planners in asphalt cuttings in road construction. Harvesting for both
salt and cornallite will be in dry condition and loading in the trucks
would be done in the same time of harvesting the truck capacity in to be
10 tonnes.
Potash
Plant
After the delivery of the harvested raw
carnallite, the crystalline crop is to be intermediately stored at a
stockpile.The carnallite then is to convey via belt conveyor to
Mashing-Milling circuite. In this circuit the crystalling crop milled
and sieved to under one millimeter and the CaCl2-Content is to
dilute.For an effective KCl production by using the cold crystallization
process, above all it is necessary to separate the valuable carnallite
crystals from the admixed NaCl as for as possible. The NaCl-Content of
4% is allowed in the feed to the decomposition to ensure the chemical
quality of the final product.To separate the NaCl from Carnallite an
inverse flotation process is employed. It means the purified Carnallite
obtained in the flotation process as underflow.This After under flow
thickening is fed to decanting centrifuge to separate the crystals from
the solution. After centrifuging the carnallite crystals contain only
short quantities of adherent solution.then the purified carnallite, is
to fed to the decomposition reactor. The decomposition takes place by
using pure water and leaching solution from following cold leaching
process.The suspension with drown from the leaching reactor is to
centrifuge completely. The wet KCl from the centrifuge goes to the
drying and cooling. The whole potash plant from intermediate storage to
sacking plant is just in an EPC contract with an Iranian Company named
Kahanroba that works with Lorgy Company in Germany have a very close
cooperation with EAT and KUTEC for the Detail Engineering.
Wining of
NaCl, MgCl2-6H2O, Mg(OH)2, CaCl2 and NO3 solutions asby-products:
NaCl- In a similar quality as it yields from the solar evaporation
process in Khor, Sodium chloride becomes recovered from sea water, and
above all it is used as table and chemical Industries.
High quality NACL can be won from the raw Sodium choloride- precipitate
from the solar ponds in Khor which extensively can be released from the
pollutants CaCl2, Ca(NO3)2 and MgCl2 by means of washing with playa
brine and water.
The lab. scale and primary pilot test show hope of success. The results
show a 99.14% purification on NaCl and the sum of the pollutants Ca, Mg,
and SO4 is less than 0.5% .
Mg(OH)2. The possibility of the production of high grade dead burnt
magnesia based on raw materials has been studies and proved. In this
regard the Basic Engineering for an Mg(OH)2 production plant with a
capacity of 30000 ton has been performed, by EAT and KUTEC jointly
The raw material of this plant are circulating solution and NaCl washing
solution, both come from potash plant.Ponds Final Brine- Solar ponds
final brine with 1.45 density and high amount of CaCl2, MgCl2 & Ca(NO3)2
is now the case of studies in Investigation Department in Khor. Primary
tests show that MgCl2 can be extracted from the brine by using potash
solution and production of carnallite in close circuit, in the further
stages the extraction of Tachydrite and the CaCl2, 12H2O and finally
Ca(NO3)2 by using simple evaporation ponds are under research
