GB2032903A - Process for Producing Potassium Silicate Fertilizer and Apparatus for Performing Said Process - Google Patents
Process for Producing Potassium Silicate Fertilizer and Apparatus for Performing Said Process Download PDFInfo
- Publication number
- GB2032903A GB2032903A GB7934229A GB7934229A GB2032903A GB 2032903 A GB2032903 A GB 2032903A GB 7934229 A GB7934229 A GB 7934229A GB 7934229 A GB7934229 A GB 7934229A GB 2032903 A GB2032903 A GB 2032903A
- Authority
- GB
- United Kingdom
- Prior art keywords
- fluidised
- drier
- product
- waste gas
- calcining furnace
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 33
- 239000004111 Potassium silicate Substances 0.000 title claims abstract description 22
- 235000019353 potassium silicate Nutrition 0.000 title claims abstract description 22
- NNHHDJVEYQHLHG-UHFFFAOYSA-N potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 title claims abstract description 22
- 229910052913 potassium silicate Inorganic materials 0.000 title claims abstract description 22
- 239000003337 fertilizer Substances 0.000 title claims abstract description 21
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims abstract description 66
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims abstract description 52
- 238000001354 calcination Methods 0.000 claims abstract description 48
- 239000008187 granular material Substances 0.000 claims abstract description 26
- 239000010881 fly ash Substances 0.000 claims abstract description 22
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 claims abstract description 21
- 238000001035 drying Methods 0.000 claims abstract description 19
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims abstract description 17
- 239000000203 mixture Substances 0.000 claims abstract description 17
- 239000011591 potassium Substances 0.000 claims abstract description 17
- 229910052700 potassium Inorganic materials 0.000 claims abstract description 17
- 238000001816 cooling Methods 0.000 claims abstract description 15
- 239000012530 fluid Substances 0.000 claims abstract description 12
- 239000003245 coal Substances 0.000 claims abstract description 11
- 229910000027 potassium carbonate Inorganic materials 0.000 claims abstract description 11
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 8
- 239000010703 silicon Substances 0.000 claims abstract description 8
- 238000004898 kneading Methods 0.000 claims abstract description 7
- 239000002912 waste gas Substances 0.000 claims description 28
- 239000000428 dust Substances 0.000 claims description 24
- 239000011230 binding agent Substances 0.000 claims description 10
- 239000002918 waste heat Substances 0.000 claims description 9
- 239000007789 gas Substances 0.000 claims description 7
- 239000000843 powder Substances 0.000 claims description 6
- 238000004806 packaging method and process Methods 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 238000010298 pulverizing process Methods 0.000 claims description 3
- 239000003232 water-soluble binding agent Substances 0.000 claims description 3
- 239000000295 fuel oil Substances 0.000 claims description 2
- 238000004064 recycling Methods 0.000 claims description 2
- 238000005243 fluidization Methods 0.000 claims 1
- 238000006243 chemical reaction Methods 0.000 abstract description 3
- 239000007858 starting material Substances 0.000 abstract description 3
- 239000000047 product Substances 0.000 description 29
- 235000011118 potassium hydroxide Nutrition 0.000 description 14
- 239000000463 material Substances 0.000 description 5
- 235000011181 potassium carbonates Nutrition 0.000 description 5
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 4
- 239000000347 magnesium hydroxide Substances 0.000 description 4
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 4
- 235000012254 magnesium hydroxide Nutrition 0.000 description 4
- 241000196324 Embryophyta Species 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- -1 i.e. Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 235000015320 potassium carbonate Nutrition 0.000 description 1
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05D—INORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C; FERTILISERS PRODUCING CARBON DIOXIDE
- C05D1/00—Fertilisers containing potassium
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/20—Silicates
- C01B33/32—Alkali metal silicates
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
- Y02P20/129—Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Processing Of Solid Wastes (AREA)
- Fertilizers (AREA)
Abstract
A process for producing potassium silicate fertilizer soluble in citric acid comprises kneading a mixture consisting essentially of potassium carbonate, fly ash, pulverized coal, other necessary starting materials and a potassium hydroxide solution and then granulating the kneaded mixture, drying the granulated product to a nearly absolutely dry state, and calcining the dried granular product, whereby a chemical reaction takes place between potassium and the silicon present in fly ash to convert them into potassium silicate soluble in citric acid. Apparatus for performing the foregoing process comprises a plurality of continuous quantitative feeders (1a to 1f) a continuous kneader (2), an extruder (3) for forming granules, a fluid drier (4), a fluid calcining furnace (6), and a cooler (8) for cooling the calcined product <IMAGE>
Description
SPECIFICATION
Process for Producing Potassium Silicate
Fertilizer and Apparatus for Performing said
Process
The invention relates to a process for producing potassium silicate fertilizer soluble in citric acid at a high yield and with a high thermal efficiency, and to apparatus for performing the said process.
As is well known, potassium fertilizer which is soluble in citric acid is dissolved by the citric acid excreted by the roots of plants, but only a certain amount of the fertilizer is dissolved and absorbed into the plants. Unlike the usual water-soluble potassium fertilizers, potassium fertilizer which is soluble in citric acid is resistant to rain water.
Further, it neutralizes acid in soil caused by the citric acid excreted by plant roots. Although potassium fertilizer soluble in citric acid is suitable for Japanese agricultural where the climate is relatively warm and rainy and the acidity of the soil is already at an advanced stage due to the use of chemical fertilizers, such as ammonium suiphate, its practical use is only rare. This is mainly attributable to the fact that if potassium silicate fertilizer soluble in citric acid is produced by the conventional process using fly ash as a silicic acid source, a continuous operation is difficult to conduct because of the high temperature necessary for calcination, which inevitably results in high cost as compared with other fertilizers. In addition, such fertilizers produced using known techniques lack uniform product quality.
Research has been conducted with the aim of overcoming the abovementioned difficulties encountered with potassium fertilizers which are soluble in citric acid. As a result, it has been discovered that an inexpensive potassium fertilizer of high quality can be produced with a high efficiency by utilizing fly ash, such as that formed in power stations operated with coal, together with inexpensive crude caustic potash (potassium hydroxide).
Fly ash is contained in waste gases formed in boilers and furnaces operated with pulverised coal, such as those in thermal power stations. The fly ash contains a large quantity of silicon. If the fly ash is admixed with a potassium source, such as caustic potash (potassium hydroxide) or potassium carbonate and calcined at a temperature of between substantially 6000 and 1,1 000C, the potassium reacts with the silicon present in fly ash to form potassium silicate soluble in citric acid.The chemical reactions that occur can be expressed by the following chemical equations:
If caustic potash (potassium hydroxide) is used as the potassium source, 2KOH+SiO2eK20 Sio2+H2o (water-soluble potassium silicate) 2KOH+nSiO2oK20.nSiO2 n=2-6 (citric acid-soluble potassium silicate)
If potassium carbonate is used as the potassium
source, K2C03+SiO2K2O.Si02+CO2 (water-soluble potassium silicate) K2CO3+nSiO2oK20.nSiO2 n=2-6 (citric acid-soluble potassium silicate)
As is well known, fly ash has a particle size of
micron order so that if one wishes to calcine it,
such as by means of a fluid calcining furnace, it
scatters in the hot air used as the calcination
medium, and the calcination cannot be carried
out.
As a result of the aforesaid research it has been
discovered that calcination can be carried out
with high efficiency if the starting materials, such
as fly ash, the potassium source and other
required materials are kneaded with a binder,
such as caustic potash (potassium hydroxide)
solution, and then the kneaded mixture is formed
into granules having a size of between
substantially 3 mm and 5 mm. The granules can
then be calcined to form a product that is usually
cooled, pulverized further, granulated and dried,
after which it is shipped as a final product.
- More particularly, the invention provides a
process for producing citric acid-soluble
potassium silicate fertilizer soluble in citric acid
comprising:
(a) forming a mixture comprising a solution of
potassium hydroxide as a binder, potassium
carbonate, fly ash and pulverized coal;
(b) kneading the mixture by means of a
continuous kneader;
(c) forming the resulting kneaded mixture into
granules by means of an extruder;
(d) drying said granules to a state of
substantially absolute dryness by means of a
fluidised drier; and
(e) calcining the resulting dried granules by
means of a fluidised calcining furnace in order to
react chemically potassium with silicon present in
the fly ash and thereby to form the potassium
silicate soluble in citric acid.
Additionally, this invention provides an
apparatus for producing potassium silicate fertilizer soluble in citric acid according to the
aforesaid process provided by this invention, which apparatus comprises:
(a) a plurality of continuous quantitative feeders for supplying the potassium hydroxide
binder, potassium carbonate, fly ash and
pulverized coal for forming the mixture;
(b) a continuous kneader for continuously
kneading the mixture;
(c) an extruder for forming the resulting
kneaded mixture into granules;
(d) a fluidised drier for drying the granules to a state of substantially absolute dryness;
(e) a fluidised calcining furnace for calcining dried granules in order to react chemically potassium with silicon present in the fly ash and thereby to form the potassium silicate soluble in citric acid, and
(f) a cooling device for cooling the resulting calcined product.
In practising this invention, the pulverized coal generates heat throughout the period during which the kneaded and granulated product is calcined in the fluidised calcining furnace, and thereby acts so as to maintain the granular product at a high temperature over a long period of time.
Alternatively the calcined product is cooled by means of a highspeed cooling device and is then pulverized into powder by means of a pulverizer, after which it is transferred to a product storage tank.
When the calcined and pulverized product is to be shipped in the form of a powdery product, it can be removed from the product storage tank by means of a screw feeder and transported to a packaging station.
When the calcined and pulverized product is to be shipped in a granular form, it can be fed by means of a screw feeder into a granulator where it can be kneaded together with an added watersoluble binder, granulated and dried, after which it can be transported to a packaging station.
In order to prepare a calcined product in a granular form the apparatus of the invention can additionally be equipped with a pulverizer for pulverizing the calcined and cooled product, a storage tank for storing the pulverized product, a granulator for kneading and granulating the product carried out of the storage tank and a second fluidised drier for drying the granulated product.
Preferably, waste gas that is discharged from the first fluidised drier is introduced into a dry dust chamber to remove floating dust, and then the removed floating dust is returned to the continuous kneader.
Preferably, waste gas that is discharged from the fluid calcining furnace is introduced into a heat exchanger and the waste heat is transmitted to low temperature air from a secondary line. The air heated thereby can then be supplied to the first fluidised drier for use as a drying medium.
Further, it is preferable to supply waste gas discharged from the cooler directly into a second fluidised drier for use as a drying medium.
It is also preferable to introduce waste gas from the second fluidised drier into a dry dust chamber where floating dust present therein is -removed. The removed floating dust can then be returned to a product storage tank.
In another embodiment of this invention, there is provided a hot air generating device where natural gas or a fuel oil is burned in order to supply a calcining medium of high temperature to the fluidised calcining furnace used for the calcination of granulated product. Peferably, waste gas discharged from the fluidised calcining furnace is returned to said hot air generating device via a heat exchanger.
It is also preferable that waste heat in waste gas discharged from the fluid calcining furnace be transmitted to the low temperature air via the first and second heat exchangers, and the air heated thereby then supplied to the second drier as a drying medium.
The accompanying drawing diagrammatically illustrates an embodiment of the invention. The single Figure 1 is a flow sheet for the production of a potassium silicate fertilizer soluble in citric acid.
Now, the invention will be described in greater detail with reference to the Figure. As shown in the left upper part of the Figure, there are provided quantitative feeders 1 a to 1 ffor continuously measuring and feeding materials.
The first continuous quantitative feeder 1 a continuously measures 48% caustic potash (KOH) and feeds it into continuous kneader 2 via line La1. Similarly, second feeder 1 b handles potassium carbonate (K2CO3), third feeder 1 C handles magnesium hydroxide (Mg(OH)2), fourth feeder 1 d handles pulverised coal and sixth feeder 1f handles fly ash. The fifth feeder 1 e is a reserve. It should be noted that the abovementioned magnesium hydroxide is optional.
The materials supplied by the continuous quantitative feeders 1 a to 1 f are kneaded in the continuous kneader 2 to give a slurry which passes lines La-2 and reaches extruder 3. The slurry is formed by extruder 3 into granules of between substantially 3 mm and 5 mm in size and the granules are then supplied to fluidised drier 4 via line La-3.
Drier 4 is of a fluidised bed type equipped with a porous plate. Hot air is blown therethrough and is recovered in heat exchanger 18, mentioned later, via line Lb-4, whereby granules on the porous plate are fluidised and dried to a state of absolute dryness containing substantially no water. The drying temperature is in the range of between substantially 2000 to 3000C. The drying time is approximately 10 minutes. This is for the reason that if drying temperature is higher than substantially 3000C, cracks occur in the granule and if it is lower than substantially 2000 C, an absolute dryness is difficult to obtain.
Floating dust leaving fluid drier 4 passes lines
Lb-5 and Lc-2 and reaches dry dust chamber 1 7 where it is recovered. Recovered material is returned to continuous kneader 2 via line Ld-l. A part of the hot air leaving drier 4 is recycled to drier 4 via lines Lb-5 and Lb-6 with the aid of recycling fan 19.
The granular product, which has been dried to the state of absolute dryness in drier 4, passes line La-4 and is supplied to fluid calcining furnace 6 by screw feeder 5. Fluid calcining furnace 6 is of a fluidised bed type equipped with a porous plate.
The granular product on the porous plate is calcined and brought into a fluidised state by the action of hot air, which has been introduced from hot air generator 16 via line Lb-1. Silicon present in fly ash reacts with potassium to form a potassium silicate soluble in citric acid. The calcining temperature in fluid calcining furnace 6 is in the range of between substantially 9000 to 1,1 000C and the time period of calcination is approximately 1 5 minutes. This is for the reason that if calcining temperature is lower than substantially 9000 C, no reaction takes place. If it is higher than substantially 1,1 000C, the granules soften to plate-like form.
Hot air generator 1 6 has an adjacent liquefied gas tank 14 from which liquefied gas is fed into hot air generator 16 via line le by pump 15. The higher temperature waste gas leaving fluid calcining furnace 6 passes line Lb-2 and reaches heat exchanger 1 8 where it releases its heat by means of heat exchange, after which it passes line
Lb-3 and reaches hot air generator 1 6 again. On the other hand, air supplied from blower 20 into heat exchanger 18 via line Lc-l and heated there passes line Lb-4 and reaches drier 4.
The product, which has completely been calcined in fluid calcining furnace 6, passes line
La-5 and is sent to high speed cooling device 8 by screw feeder 7. High speed cooling device 8 is a fluidised bed type of cooler equipped with a porous plate. Cold air supplied by cooling fan 21 via line Lb-7 fluidises the calcined product and rapidly cools it. Hot air leaving the high speed cooling device 8 passes line Lb-8 and reaches second fluidised drier 13 mentioned hereinafter, where it is used as a drying medium for the drier 13. The residence time of calcined product in the high speed cooling device 8 is approximately 10 minutes.
Product cooled in high speed cooling device 8 passes line La-6 and reaches pulverizer 9 where it is pulverized into powder, after which it is transported to product tank 10 via line La-7.
Floating dust leaving product tank 10 passes line
Lc-3 and is recovered, after which it is returned to pulverizer 9 via Lc-4 by a transporting fan 22. The product in storage tank 10 is shipped as a powdery productA-l via screw feeder 11 and line
La-8. Otherwise, the product is sent to granulator 12 where it is kneaded together with a binder, i.e., water or other water-soluble binder fed from binder tank 23 via line Lf, and granulated, after which it passes line La-9, is dried in the second drier 13, passes line La-lO and is then shipped as a granular productA-2. Floating dust leaving the second drier 13 passes line Lc-5, is recovered in dry dust chamber 24, then passes line Ld-2 and is finally recovered in line La-7.
Waste gas leaving dry dust chamber 1 7 is driven by waste gas fan 25 and passes lines Lc-6 and Lc-8 to be released into the atmosphere from chimney 27, while waste gas leaving dry dust chamber 24 is driven by waste gas fan 26 and passes lines Lc-7 and Lc-9 to be released into the atmosphere via chimney 27.
A practical example of the above-mentioned process is now described. Starting materials were measured in continuous quantitative feeders Ia- ifin the following proportions:
0.88 Tonnes/Hour (T/H) of 45% caustic potash (KOH) solution as a binder,
0.436 T/H of potassium carbonate,
0.136 T/H of magnesium hydroxide,
0.4 T/H of pulverized coal, and
2.148 T/H of fly ash.
The materials were passed to continuous kneader 2 and kneaded therein. After kneading, the starting mixture was supplied as a slurry to extruder 3 where it was granulated into cylindrical granules having a diameter of 3 mm and a length of 5 mm.
Then, the granules were sent to drier 4 where they were dried at 2500C for 10 minutes until they reached absolute dryness. Subsequently, the granules were passed to the fluidised calcining furnace 6 where they were calcined at 1 ,0000C for 15 minutes. After calcination, the product was passed to the high speed cooler 8 where it was cooled with cold air for 1 5 minutes.
Claims (29)
1. A process for producing potassium silicate fertilizer soluble in citric acid, said process comprising:
(a) forming a mixture comprising a solution of potassium hydroxide as a binder, potassium carbonate, fly ash and pulverized coal;
(b) kneading said mixture by means of a continuous kneader;
(c) forming the resulting kneaded mixture into granules by means of an extruder;
(d) drying said granules to a state of substantially absolute dryness by means of a fluidised drier; and
(e) calcining the resulting dried granules by means of a fluidised calcining furnace in order to react chemically potassium with silicon present in the fly ash and thereby to form the potassium silicate soluble in citric acid.
2. The process according to Claim 1, wherein the product resulting from said fluidised calcining furnace is cooled by means of a high speed cooling device, then pulverized into powder by means of a pulverizer, transported to a product storage tank and stored therein.
3. The process according to Claim 2, wherein the powder is carried out of said product storage tank by means of a screw feeder and shipped as a powdery product.
4. The process according to Claim 2, wherein the powder is moistened and then granulated by means of a screw feeder, and the product thus granulated is dried by means of a second fluidised drier and shipped as a granular product.
5. The process according to Claim 4, wherein said powder is moistened with water or a watersoluble binder.
6. The process according to Claim 1, wherein waste gas containing floating dust is led from said fluidised drier and said dust is captured by means of a dry dust chamber and returned to said continuous kneader.
7. The process according to Claim 1, wherein waste gas is led from said fluidised drier and a part of said waste gas is accelerated by means of a recycling fan and returned to the fluidised drier.
8. The process according to Claim 1, wherein waste gas at a high temperature is led from said fluidised calcining furnace and said gas is introduced to a heat exchanger to transmit waste heat to low temperature air from a secondary source and the air thus heated is supplied to said fluidised drier and is used as a drying medium.
9, The process according to Claim 1, wherein waste gas at a high temperature is led from said fluidised calcining furnace and said gas is introduced to a heat exchanger to transmit waste heat to low temperature air from a secondary source and said gas is thereafter returned to a generator to provide hot air to said calcining furnace.
10. The process according to Claim 2, wherein waste gas at a high temperature is led from said high speed cooling device and said waste gas is supplied to said fluidised drier and is used as a drying medium.
11. The process according to Claim 2 or 4 wherein waste gas at a high temperature is led from said high speed cooling device and said waste gas is introduced to a second fluidised drier and is used as a drying medium.
12. The process according to Claims 1 or 4, wherein waste gas at a high temperature is led from said fluidised calcining furnace, and said waste gas is led to a heat exchanger to transmit waste heat to low temperature air from a secondary source, the air thus heated is led to a primary line of a second heat exchanger to transmit its heat to air from a secondary line and the air thus heated is led to a second fluidised drier and is uxed as a drying medium.
13. The process according to Claim 11, wherein waste gas leaving the second fluidised drier contains floating dust and said dust is captured by means of a dry dust chamber and is returned to a product storage tank.
14. The process according to any preceding claim, wherein a high temperature gas obtained by burning a liquefied gas or a fuel oil in a hot air generator is supplied to said fluid calcining furnace and is used as a calcining medium.
1 5. The process according to any preceding claim, wherein drying in said fluidised drier is carried out at a temperature of between substantially 2000C and 3000C for substantially 10 minutes.
16. The process according to any one of Claims 1-14, wherein calcination in said fluidisation calcining furnace is carried out at a temperature of between substantially 6000C and 1,1000C for substantially 1 5 minutes.
1 7. The process according to any preceding claim, wherein said granules have a size of between substantially 3 mm and 5 mm.
18. An apparatus for producing potassium silicate fertilizer soluble in citric acid according to the process of Claim 1 comprising:
(a) a plurality of continuous quantitative feeders for supplying potassium hydroxide binder, potassium carbonate, fly ash and pulverized coal for forming said mixture;
(b) a continuous kneader for continuously kneading said mixture:
(c) an extruder for forming the resulting kneaded mixture into granules;
(d) a fluidised drier for drying the granules to a state of substantially absolute dryness;
(e) a fluidised calcining furnace for calcining dried granules in order to react chemically potassium with silicon present in the fly ash and thereby to form the potassium silicate soluble in citric acid, and
(f) a cooling device for cooling the resulting calcined product.
1 9. Apparatus according to Claim 18, additionally equipped with:
a pulverizer for pulverizing the calcined and cooled product;
a product storage tank for storing the product pulverized in said pulverizer:
a screw feeder for transporting the product to said product storage tank; and
means for removing the pulverized product from said storage tank and transporting it to packaging means.
20. Apparatus according to Claim 18, additionally equipped with:
a pulverizer for pulverizing the calcined and cooled product:
a product storage tank for storing the product pulveried in said pulverizer;
a screw feeder for transporting the product to said product storage tank;
means for adding a binder to the pulverized product;
a granulator for granulating the resulting binder-containing mixture into granules;
a second fluidised drier for drying the granules formed by said granulator; and
means for removing the granular product from said second fluidised drier and transporting it to packaging means.
21. Apparatus according to Claim 1 9, wherein said fluidised drier is equipped with a dry dust chamber for recovering floating dust in waste gas from said drier, said dry dust chamber being connected to said fluidised drier via piping.
22. Apparatus according to Claim 19, wherein said fluidised calcining furnace is equipped with a hot air generator for generating a calcining medium, said hot air generator being connected to said fluidised calcining furnace via piping.
23. Apparatus according to Claim 19, wherein said fluidised calcining furnace is equipped with a heat exchanger for recovering waste heat from waste gas from said furnace, said heat exchanger being connected with said fluidised calcining furnace via piping, waste heat recovering being utilised in the fluidised drier.
24. Apparatus according to Claim 19, wherein said fluidised calcining furnace is equipped with a first heat exchanger and a second heat exchanger for recovering waste heat, both these heat exchangers being connected to said calcining furnace via piping, waste heat recovered being utilised in a second fluidised drier.
25. Apparatus according to Claim 20, wherein said second fluidised drier is equipped with a recovering device for floating dust present in waste gas therefrom, said recovering device being connected to said second drier via piping.
26. Apparatus according to Claim 24, wherein said second heat exchanger is equipped with a recovering device for floating dust present in waste gas after heat exchanger in said second heat exchanger said recovering device being connected to said second fluidised drier via piping.
27. Apparatus according to Claim 19, wherein said plurality of quantitative feeders include at least one reserve feeder.
28. Apparatus according to Claim 18, wherein said feeders continuously measure and feed the potassium hydroxide, potassium carbonate, the fly ash and the pulverized coal respectively at predetermined rates.
29. Apparatus for producing potassium silicate fertilizer soluble in citric acid according to the process of Claim 1, the apparatus being constructed and arranged substantially as described herein with reference to the accompanying drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12366878A JPS5551784A (en) | 1978-10-09 | 1978-10-09 | Method and apparatus for manufacturing potassium silicate fertilizer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2032903A true GB2032903A (en) | 1980-05-14 |
| GB2032903B GB2032903B (en) | 1983-05-11 |
Family
ID=14866331
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7934229A Expired GB2032903B (en) | 1978-10-09 | 1979-10-03 | Process for producing potassium silicate fertilizer and apparatus for performing said process |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5551784A (en) |
| AU (1) | AU529781B2 (en) |
| CA (1) | CA1125534A (en) |
| DE (1) | DE2939978C2 (en) |
| FR (1) | FR2438637A1 (en) |
| GB (1) | GB2032903B (en) |
| ZA (1) | ZA795023B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019167036A1 (en) | 2018-02-27 | 2019-09-06 | Dead Sea Works Ltd. | Potash dust granulation process |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH645083A5 (en) * | 1980-05-20 | 1984-09-14 | Escher Wyss Ag | METHOD AND DEVICE FOR RECALCINATING A SLAVE CONTAINING CALCIUM CARBONATE. |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1252212B (en) * | ||||
| JPS5122570A (en) * | 1974-08-14 | 1976-02-23 | Ube Industries | Kankoseikarihiryono seizohoho |
-
1978
- 1978-10-09 JP JP12366878A patent/JPS5551784A/en active Pending
-
1979
- 1979-09-21 ZA ZA00795023A patent/ZA795023B/en unknown
- 1979-10-02 DE DE2939978A patent/DE2939978C2/en not_active Expired
- 1979-10-03 GB GB7934229A patent/GB2032903B/en not_active Expired
- 1979-10-05 FR FR7924921A patent/FR2438637A1/en active Granted
- 1979-10-05 CA CA337,070A patent/CA1125534A/en not_active Expired
- 1979-10-09 AU AU51594/79A patent/AU529781B2/en not_active Ceased
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019167036A1 (en) | 2018-02-27 | 2019-09-06 | Dead Sea Works Ltd. | Potash dust granulation process |
| EP3758836A4 (en) * | 2018-02-27 | 2021-11-24 | Dead Sea Works Ltd. | Potash dust granulation process |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2438637A1 (en) | 1980-05-09 |
| AU529781B2 (en) | 1983-06-23 |
| GB2032903B (en) | 1983-05-11 |
| CA1125534A (en) | 1982-06-15 |
| DE2939978C2 (en) | 1983-12-22 |
| JPS5551784A (en) | 1980-04-15 |
| DE2939978A1 (en) | 1980-04-24 |
| FR2438637B1 (en) | 1982-06-25 |
| ZA795023B (en) | 1980-09-24 |
| AU5159479A (en) | 1980-04-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |