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The varieties of potassium fertilizer
produced in China include potassium chloride, potassium sulphate
and potassium nitrate. Currently, there are 50 enterprises
producing potassium fertilizer in China, among which the number
of potassium sulphate production enterprises is more than
40. At present, the total production capacity of potassium
fertilizer in China is 910,000 tons (as K2O), of
which the production of potassium sulphate is 500,000 tons/year
(as K2O), the production of potassium chloride
is 360,000 tons/year (as K2O), while the production
of potassium nitrate for agriculture use is very small with
the capacity of only about 50,000 tons/year (as K2O).
China has made important breakthroughs in
counter-floatation, cold-crystallization process for potassium
chloride production, and in the designing and manufacturing
of the involved mining equipment. It has successfully designed
and manufactured the first large-scale mining ship and the
largest crystalizer in China and has obtained the technology
with its own intellectual property in abstracting potassium
chloride from salt lakes.
China's potassium sulphate production has
got a considerable capacity with varieties of technologies.
Currently, China not only possesses the processes developed
by itself, such as Glauber's salt method, liquid (solid) phase
method and ammonia sulphate method, but also has several sets
of plant for the production of potassium sulphate by Mannheim
process.
Potassium nitrate is a high-quality, chlorine-free
potassium fertilizer. In addition to containing 45% of K2O,
it contains 14% of nitronitrogen. As a compound fertilizer
of high quality and high efficiency, it is widely used in
manuring the plants to which chlorine must be avoided, such
as tobacco, coffee, tomato, grape, orange, gardening, flowers,
potato, avocado, tea, vegetable and mango. At present, the
main potassium nitrate production methods in China include
double decomposition method and ion exchange method. The process
of vacuum-crystallization, double-decomposition developed
and the relevant engineering undertaken by ECEC is a production
method with the most competitive power in China.
ECEC is one of the earliest engineering companies
engaged in potassium fertilizer technology development and
project construction in China. Since the mid-1980s, it has
been working on the research and development of potassium
fertilizer, especially in the field of potassium nitrate fertilizer.
In 1997, ECEC developed the first plant in China for the production
of ten thousand tons of potassium nitrate using the new technology
of vacuum-crystallization and double-decomposition process,
and the production plant using the said process had reached
its quality and capacity standards in October 2000. In addition,
ECEC maintains good business relations with a number of companies
engaged in the production and research of potassium sulphate.
Sample project:
10,000 t/a Potassium Nitrate Plant
Client: Yunnan Wotewei Chemical Co., Ltd.
| Plant capacity: |
10,000 t/a potassium nitrate. |
| Technology source: |
ECEC. |
| Process flow: |
The raw material, which is potassium
chloride, is put into the No.1 reaction tank with an
agitator, where it takes part in a double decomposition
reaction with the NH4NO3 in the
secondary mother liquor from which KNO3 and
NH4Cl has been separated. The reaction liquid,
after completely reacted in No.1 and No.2 reactors,
flows into an intermediate tank.
The reaction liquid from the intermediate tank is cooled
through a plate-type heat exchanger together with the
primary mother liquor from which KNO3 crystals
have been separated, and then it is sent to a vacuum
cooling crystalizer, where the reaction liquor is cooled
and most of KNO3 are crystallized out. The
crystallization liquid is thickened through a thickener
and then goes through a centrifuge to separate out the
product KNO3. The primary mother liquor so
obtained is further processed in a double-effect evaporation
and concentration after heat exchanging with the reaction
liquid, and is then sent into a NH4Cl cold-precipitating
crystallizer to make most of the NH4Cl precipitate,
crystallize and grow up. The crystallization liquid
is thickened by a thickener and then goes through a
centrifuge to separate out the by-product of NH4Cl.
The secondary mother liquor so obtained flows back into
the reaction tank. The secondary steam condensate from
evaporation and concentration is also added into the
reaction tank for reuse as make-up water. |
| Work scope of ECEC: |
Supply of process technology, engineering
design, technical service, construction/installation
supervision as well as start-up supervision. |
| Construction period: |
1998~2000. |
| Operation: |
The plant was built up and put
into operation in August 2000, and reached the design
capacity and quality standard in October 2000. |
Currently, the daily production of the plant has reached
42t, which is over 120% of the designed capacity. The quality
of the product meets the design requirements, the analysis
of which are as follows:
| Potassium nitrate: |
|
| |
| K2O |
Cl |
N |
H2O |
| 44.96% |
0.8% |
14.3% |
3% |
|
| Ammonium chloride: |
|
| |
| N |
K2O |
H2O |
| 22.2% |
5.4% |
3.5% |
|
|
