GB2077722A - A Process for the Production of Urea Granules - Google Patents
A Process for the Production of Urea Granules Download PDFInfo
- Publication number
- GB2077722A GB2077722A GB8115005A GB8115005A GB2077722A GB 2077722 A GB2077722 A GB 2077722A GB 8115005 A GB8115005 A GB 8115005A GB 8115005 A GB8115005 A GB 8115005A GB 2077722 A GB2077722 A GB 2077722A
- Authority
- GB
- United Kingdom
- Prior art keywords
- urea
- granules
- magnesium oxide
- melt
- solution
- 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
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05C—NITROGENOUS FERTILISERS
- C05C9/00—Fertilisers containing urea or urea compounds
- C05C9/005—Post-treatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
- B01J2/30—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic using agents to prevent the granules sticking together; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05B—PHOSPHATIC FERTILISERS
- C05B19/00—Granulation or pelletisation of phosphatic fertilisers, other than slag
- C05B19/02—Granulation or pelletisation of phosphatic fertilisers, other than slag of superphosphates or mixtures containing them
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C273/00—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
- C07C273/02—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of urea, its salts, complexes or addition compounds
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Fertilizers (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Medicinal Preparation (AREA)
- Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
Abstract
The production of urea granules by prilling or granulating a urea melt or an aqueous urea solution, which melt or solution contains a magnesium oxide containing additive. The urea granules thus obtained exhibit a high crushing strength, a high apparent density, and a very low caking tendency, and are suitable for bulk blending with single and triple superphosphate granules.
Description
SPECIFICATION
A Process for the Production of Urea Granules
This invention relates to a process for the production of urea granules.
For the production of urea granules, various methods are known. One of these is trilling, by which in this specification is understood a method in which a substantially anhydrous urea melt (having a water content of no more than 0.1 to 0.3 % by weight) is sprayed in the top of a prilling column in a rising stream of air of ambient temperature, in which the droplets solidify. The resulting prills have a maximum diameter of not much more than 3 mm, and are mechanically rather weak.
Urea granules having larger dimensions and better mechanical properties can be produced by the granulation of a substantially anhydrous urea melt in a drum generator, for example, by the sledrozier technique as described in British Patent Specification No. 894,773, or in a pan granulator, for example as described in U.S.Patent Specification No. 4,008,064, or by the granulation of an aqueous urea solution in a fluidized bed, for example as described in Dutch patent application 780621 3. In the process described in the last-mentioned publication, an aqueous urea solution having a urea concentration of 7099.9% by weight, preferably 8596% by weight, is sprayed in the form of very fine droplets having an average diameter of 20-120 micron into a fluidized bed of urea particles at a temperature at which the water evaporates from the solution sprayed onto the particles, and urea solidifies on the particles to form granules having a desired size which may be 25 mm and more, As rather large amounts of flydust are formed in this process, especially if the urea solution used as the starting material contains more than 5% by weight of water, in particular more than 10% by weight of water, preferably a crystallization retarder for the urea, in particular a water-soluble addition or condensation product of formaldehyde and urea, is added to the urea solution, whereby the formation of flydust is suppressed practically completely. The result of the presence of the crystallization retarder is that the granules remain plastic as they are being formed, so that owing to rolling and/or impacts during the formation mechanically strong, smooth and round granules may be formed.
The resulting granules have a high crushing strength, a high impact resistance, and little tendency of forming flydust through abrasion, and moreover do not cake together, not even upon prolonged storage, although urea exhibits a strong natural tendency of caking together.
Urea granules produced according to one of the known methods cannot be used for the production of heterogeneous binary and ternary fertilizer mixtures, such as N-P or N-P-K mixtures by bulk blending with the cheap superphosphate or triple superphosphate, as such urea granules are incompatible with these phosphates. Mixtures of such urea granules with superphosphate or triple superphosphate granules deliquesce after some time to form an unmanageable and unusable mud.
According to a paper by G. Hoffmeister and G. H. Megar, presented during "The Fertilizer Industry
Round Table" on November 6, 1975, at Washington D.C., this incompatibility is caused by a reaction according to the following equation Ca(H2PO4)2.H20+4CO(NH2)2oCa(H2PO4)2 4CO(NH2)2+H20 By the reaction of 1 mol monocalcium phosphate monohydrate, the main component of superphosphate and triple superphosphate, with 4 mols urea, a urea-monocalcium phosphate adduct is formed, with 1 mol water being released. As the adduct has a high solubility, it is readily dissolved in the water liberated to form a large volume of solution, which wets the granules in the mixture, owing to which the reaction proceeds at an ever faster rate.Up until now, no commercially acceptable means have been found to make urea compatible with superphosphate or triple superphosphate. As a consequence, it is virtually only the more expensive phosphate fertilizers monoammonium phosphate and diammonium phosphate that can be used for bulk blending with urea.
It is an object of the present invention to provide a process for the production of urea granules having preferred properties, including compatibility with superphosphate and triple superphosphate granules.
The invention provides a process for the production of urea granules by prilling or granulating a urea melt or an aqueous urea solution, which process is characterized in that the urea melt or solution to be prilled or granulated contains a magnesium oxide containing additive.
It has surprisingly been found that the granules produced according to the invention are compatible with superphosphate and triple superphosphate granules, by virtue of which they are suitable for bulk blending with these phosphate fertilizers. Mixtures of urea granules obtained according to the invention with superphosphate granules or triple superphosphate granules that were subjected to the "TVA Bottle Test" at 270C were still dry after 7 weeks, whereas analogous mixtures with urea granules not produced in accordance with the invention had deliquesced completely after 3 days.
It has further been found that the presence of magnesium oxide during the prilling or granulation of a urea melt or solution has for its result that the building-up of the granules proceeds flawlessly, and the formation of flydust is prevented, while in addition the resulting urea granules have a very high crushing strength and a very high apparent specific gravity. A further highly surprising feature is that the urea granules produced according to the invention do not cake together, not even upon prolonged storage.
The magnesium oxide can be used as such (MgO) or in the form of fully calcined dolomite (MgO+CaO) or a selectively calcined dolomite (MgO+CaCO3). A beneficial effect is already observed with a quantity of additive corresponding to 0.1% by weight of MgO, calculated on the urea in the melt or solution. Preferably the additive is used in a quantity corresponding to 0.52% by weight of MgO, calculated on the urea in the melt or solution. If desired, higher proportions may be used, but this does not seem to offer any particular advantages. The additive may be added in the form of a powder to the urea melt or solution prior to prilling or granulating.
Preferably, after their formation the granules are cooled to 300C or to a lower temperature, for example by means of a stream of air, the moisture content of which has preferably been reduced to such an extent that during the cooling process the granules do not absorb moisture from the cool air.
The invention also relates to compatible, heterogeneous fertilizer mixtures of urea granules obtained by the process according to the present invention with superphosphate or triple superphosphate granules, and, if desired, one or more other granular substances.
In addition to urea and superphosphate or triple superphosphate, a potassium fertilizer is mostly
included in the mixture, such as KCI. To prevent segregation of the mixture, the granule dimensions of the components to be blended must be adapted to one another.
For further information regarding the production of fertilizer granules, reference is made with
regard to prilling to U.S. Patent Specification No. 3,130,225 with regard to granulation in a pan
generator to U.S. Patent Specification No. 4,008,064, with regard to granulation in a drum generator
to British Patent Specification No. 894,773 and with regard to granulation in a fluidized bed to Dutch
patent application 7806213.
The effect of the process according to the invention is shown in and by the following examples.
The "TVA Bottle Test" referred to in the examples serves to determine the compatibility of urea
granules with superphosphate and triple superphosphate granules. In this test, a mixture of the urea
granules to be tested with superphosphate or triple superphosphate granules was kept in a closed
bottle of 120 cm3 at 270C, and the condition was periodically inspected. The condition observed is
evaluated as follows:
Condition of the mixture
D=dry, free-flowing
W-1=moisture patches, but usable
W-2=moist and slightly sticky, but probably usable
W-3=wet through and sticky, unsuitable for use
W-4=very wet, unsuitable for use
H=hard caked together, unsuitable for use.
In the "bag test" referred to in the examples, the caking tendency of the granules tested was determined. In this test urea granules were packed in bags of 35 kg, which were stored under a weight of 1000 kg at 270C. After 1 month, the average number of lumps per bag was determined, and the
average hardness of the lumps was measured, By hardness is understood here the force in kg,
exercised by a dynamometer to cause a lump of 7x7 x5 cm to disintegrate.
The crystallization retarder F 80, referred to in the examples, is a clear viscous liquid
commercially available under the name of "Formurea 80", which is stable between -200C and +400C, and upon analysis is found to contain per 100 parts by weight approximately 20 parts by
weight of water, approximately 23 parts by weight of urea and approximately 57 parts by weight of formaldehyde, approximately 55% of the formaldehyde being bound as trimethyl urea, and the balance
being present in the unbound state.
Example I
Tests were conducted in which an aqueous urea solution with and without a known
crystallization retarder (F 80) and with magnesium oxide as a crystallization retarder was sprayed into a fluidized bed of urea particles, The granulation conditions and the physical properties of the resulting
granules are listed in Table A.
Table A
Crystallization retarder none 1% F80 0.6 MgO 1%MgO Granulation conditions
urea solution
concentration, % by weight 94.6 94.5 94.5 94.5
temperature, OC 130 130 1 30 130
rate of flow, kg/h 280 280 280 280
Table A (cont.)
Crystallization retarder none 1%F80 0.6 MgO 1% MgO
injection air
rate of flow, Nm3/h 130 130 130 130
temperature, OC 140 140 140 140
fluidization air
rate of flow, Nm3/h 850 850 850 850
temperature, OC 45 64 54 58
bed temperature, OC 108 105 104 104
Product properties
apparent density, g/cm3 1.23 1.26 1.30 1.31
crushing strength dia. 2.5 mm, kg 2.1 2.8 4.0 4.3
fly dust, g/kg 5.4 < 0.1 0.1 < 0.1
bag test lumps, % 100 10 0 0
hardness, kg 22 0.1 0 0 TVA Bottle Test with superphosphate (SSP) 50/50
after 1 day W-2 W-2 D D
after 3 days W-4 W-4 D D
after 7 days W-4 W-4 D D
after 14 days W-4 W-4 W-1 D
after 21 days W-4 W-4 W-1 D
after 50 days W-4 W-4 W-1 D with triple superphosphate (TSP) 50/50
after 1 day W-2 W-2 D D
after 3 days W-4 W-4 D D
after 7 days W-4 W-4 D D
after 14 days W-4 W-4 W-1 D
after21 days W-4 W-4 W--1 fl after 50 days W-4 W-4 W-1 D
Example II
A subsequent series of tests were conducted analogously to those described in Example I, but
using selectively calcined dolomite and completely calcined dolomite as crystallization retarders
instead of magnesium oxide.The granulation conditions and the physical properties of the resulting
granules are listed in Table B.
Table B
selectively calcined completely calcined
dolomite dolomite
Crystallization retarder none 1.5% 3% 1.5% 3%
Granulation conditions
urea solution
concentration, % by weight 94.5 95.5 95.5 95.5 95.5 temperature, OC 130 130 130 130 130
rate of flow, kg/h 200 220 220 220 220
injection air rateofflow,Nm3/h 130 130 130 130 130 temperature, OC 140 134 149 150 149
fluidization air
rate of flow, Nm3/h 850 850 850 850 850
temperature, OC 58 75 66 53 57
bed temperature, OC 100 98 92 95 94
Table B (cont.)
completely calcined selectively calcined
dolomite dolomite
Crystallization retarder none 1.5% 3% 1.5% 3%
Product properties
apparent density, g/cm3 1.22 1.29 1.31 1.29 1.32
crushing strength, dia.2.5mm/kg 1.9 4.0 3.9 3.7 3.4
fly-dust, g/kg 2.2 0 0 0 0 bag test lumps, % 100 9 7 10 '23
hardness, kg 13 < 1 < 1 2 2
TVA Bottle Test
with SSP 50/50 after 3 days 14 days 14 days more than 60 more than 60
deliquesced usable usable days usable days usable
with TSP 50/50 after 3 days 14 days 14 days more than 60 more than 60
deliquesced usable usable days usable days usable
Example lil A substantially anhydrous urea melt with and without added magnesium oxide was sprayed in
the top of a prilling column in a rising stream of air of ambient temperature. The physical properties of
the resulting prills are listed in Table C.
Table C
Additive none 0.72% MgO 0.95% MgO
Product properties
apparent density, g/cm3 1.30 1.32 1.33
crushing strength, dia. 0.54 1.04 1.16
2.5 mm, kg
bag test lumps,% 100 0 0
hardness,kg. 9 0 0
TVA Bottle Test
with SSP 50/50 after 3 days more than 60 more than 60
deliquesced days usable days usable
with TSP 50/50 after 3 days more than 60 more than 60
deliquesced days usable days usable
Example IV
A urea melt to which magnesium oxide had been added was granulated in a rotary horizontal
granulation drum having a diameter of 90 cm and a width of 60 cm. The drum was provided on its
inner wall with eight longitudinal strips of 3.5 x 60 cm spaced equal distances from each other. The
speed was 1 5 rpm.The drum was filled with 60 kg urea granules having an average diameter of 1.8
mm and a temperature of 800C. Using two hydraulic sprayers, 60 kg anhydrous urea melt (99.8% by
weight of urea), to which 0.6% by weight of MgO had been added, having a temperature of 140 1 450C was sprayed into the rotary drum at a rate of approximately 100 kg/h over the granules
showered from the longitudinal strips. The granulation was effected at 11 00C.
At the end of the test, the granules were cooled to approximately 300C and sieved. The product
granules had a good roundness and a smooth surface. Their apparent density was 1.288 g/cm3 and the
crushing strength dia. 2.5 mm was 3.5 kg. Flydust formation was 3.9 g/kg. The granules had virtually
no caking tendency. 50/50 blends with SSP and with TSP were usable for more than 60 days. The
sieve analysis of the product was as follows:
> 4.00 mm: 17% 4.00-2.5 mm: 46% 2.5-2.0 mm: 29%
< 2.0 mm: 8%
average diameter: 3.0 mm.
Claims (13)
1. A process for the production of urea granules or urea coated granules, wherein the granule forming or growing, urea containing liquid incorporates or contains magnesium oxide.
2. A process for the production of urea granules by prilling or granulating a urea melt or an aqueous urea solution, characterized in that the urea melt or solution to be prilled or granulated contains a magnesium oxide containing additive.
3. A process as claimed in claim 2, wherein the additive is magnesium oxide per se.
4. A process as claimed in claim 1 or 2, wherein the magnesium oxide is incorporated or contained in the form of selectively or completely calcined dolomite.
5. A process as claimed in any one of claims 1 to 4, wherein the amount of additive corresponds to at least 0.1% by weight of MgO calculated on the urea in the melt or solution.
6. A process as claimed in claim 5, wherein the amount of additive corresponds to from 0.5 to 2% by weight of MgO, calculated on the urea in the melt or the solution.
7. A process for the production of urea granules as defined in claim 2, and substantially as hereinbefore described with reference to any one of the foregoing individual examples I to IV.
8. Urea granules produced by a process as claimed in any one of the preceding claims.
9. A compatible heterogeneous fertilizer blend comprising urea granules produced by a process as defined in any one of claims 1 to 7 and single or triple superphosphate granules.
10. A blend as claimed in claim 9, further comprising a granular fertilizer such as KCL.
11. Urea granules containing or incorporating magnesium oxide.
12. Granules having a coating of urea which contains or incorporates magnesium oxide.
13. The features hereinbefore desclosed or their novel equivalents in any combination.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL8002912A NL8002912A (en) | 1980-05-20 | 1980-05-20 | METHOD FOR MAKING UREA GRANULES, AND ARTICLES OF FERTILIZER MIXTURES INCLUDED THEREFORE. |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2077722A true GB2077722A (en) | 1981-12-23 |
| GB2077722B GB2077722B (en) | 1984-02-15 |
Family
ID=19835332
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8115005A Expired GB2077722B (en) | 1980-05-20 | 1981-05-15 | A process for the production of urea granules |
Country Status (28)
| Country | Link |
|---|---|
| JP (1) | JPS6035320B2 (en) |
| AT (1) | AT375917B (en) |
| BE (1) | BE888842A (en) |
| BG (1) | BG49613A3 (en) |
| BR (1) | BR8103139A (en) |
| CA (1) | CA1157288A (en) |
| CS (1) | CS259506B2 (en) |
| DD (1) | DD159040A5 (en) |
| DE (1) | DE3118454C2 (en) |
| EG (1) | EG15440A (en) |
| ES (1) | ES502903A0 (en) |
| FI (1) | FI71721C (en) |
| FR (1) | FR2482871B1 (en) |
| GB (1) | GB2077722B (en) |
| GR (1) | GR75604B (en) |
| HU (1) | HU184438B (en) |
| IE (1) | IE51964B1 (en) |
| IN (1) | IN153960B (en) |
| IT (1) | IT1136617B (en) |
| MX (1) | MX160067A (en) |
| NL (2) | NL8002912A (en) |
| NO (1) | NO151648C (en) |
| PL (1) | PL134458B1 (en) |
| PT (1) | PT73053B (en) |
| SE (1) | SE446625B (en) |
| TR (1) | TR21674A (en) |
| YU (1) | YU42568B (en) |
| ZA (1) | ZA813280B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2504909A1 (en) * | 1981-05-04 | 1982-11-05 | Gattys Ing Buero F J | PROCESS FOR THE STABILIZATION OF DEHYDRATED MAGNESIUM CHLORIDE AGAINST RE-HYDRATION |
| WO1995021689A1 (en) * | 1994-02-11 | 1995-08-17 | Incitec Ltd. | Granular urea |
| AU679330B2 (en) * | 1994-02-11 | 1997-06-26 | Incitec Ltd | Granular urea |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GR76402B (en) * | 1981-07-03 | 1984-08-10 | Azote Sa Cie Neerlandaise | |
| NL8502838A (en) * | 1985-10-17 | 1987-05-18 | Azote Sa Cie Neerlandaise | METHOD FOR MANUFACTURING UREA AND AMMONIUM SULFATE CONTAINING FERTILIZER GRAINS. |
| DE4232567C1 (en) * | 1992-09-29 | 1994-02-10 | Kali & Salz Ag | Granular sulphate fertiliser treatment to prevent dust formation during bulk transformation - comprises spraying with conc. urea soln. |
| DE102005018949A1 (en) * | 2005-04-18 | 2006-10-19 | Ami-Agrolinz Melamine International Gmbh | Solid particles production, especially urea particles, from flowable starting material containing e.g. actinium oxide, useful e.g. in catalysts or milling bodies, comprises splitting into droplets and introducing into solidification liquid |
| DE102021108187A1 (en) | 2021-03-31 | 2022-10-06 | Skw Stickstoffwerke Piesteritz Gmbh | Granulated pH neutral urea ammonium sulphate fertilizer with urease inhibitor |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB731686A (en) * | 1952-06-25 | 1955-06-15 | Ici Ltd | Improvements in and relating to urea compositions |
| GB837163A (en) * | 1958-01-31 | 1960-06-09 | Ici Ltd | Improvements in and relating to urea compositions |
| GB1220826A (en) * | 1967-09-13 | 1971-01-27 | Fisons Ltd | Process for the production of particulate urea |
-
1980
- 1980-05-20 NL NL8002912A patent/NL8002912A/en not_active Application Discontinuation
-
1981
- 1981-05-04 NL NL8102191A patent/NL8102191A/en not_active Application Discontinuation
- 1981-05-09 DE DE3118454A patent/DE3118454C2/en not_active Expired
- 1981-05-12 IE IE1062/81A patent/IE51964B1/en unknown
- 1981-05-12 IN IN501/CAL/81A patent/IN153960B/en unknown
- 1981-05-12 GR GR64915A patent/GR75604B/el unknown
- 1981-05-12 CA CA000377380A patent/CA1157288A/en not_active Expired
- 1981-05-14 AT AT0215381A patent/AT375917B/en not_active IP Right Cessation
- 1981-05-15 GB GB8115005A patent/GB2077722B/en not_active Expired
- 1981-05-15 FR FR8109729A patent/FR2482871B1/en not_active Expired
- 1981-05-18 ZA ZA00813280A patent/ZA813280B/en unknown
- 1981-05-19 PT PT73053A patent/PT73053B/en not_active IP Right Cessation
- 1981-05-19 NO NO811697A patent/NO151648C/en unknown
- 1981-05-19 CS CS813720A patent/CS259506B2/en unknown
- 1981-05-19 BE BE2/59164A patent/BE888842A/en not_active IP Right Cessation
- 1981-05-19 MX MX187383A patent/MX160067A/en unknown
- 1981-05-19 FI FI811539A patent/FI71721C/en not_active IP Right Cessation
- 1981-05-19 JP JP56074344A patent/JPS6035320B2/en not_active Expired
- 1981-05-19 HU HU811441A patent/HU184438B/en not_active IP Right Cessation
- 1981-05-19 YU YU1285/81A patent/YU42568B/en unknown
- 1981-05-19 IT IT21817/81A patent/IT1136617B/en active
- 1981-05-19 SE SE8103139A patent/SE446625B/en not_active IP Right Cessation
- 1981-05-20 ES ES502903A patent/ES502903A0/en active Granted
- 1981-05-20 BG BG052155A patent/BG49613A3/en unknown
- 1981-05-20 TR TR21674A patent/TR21674A/en unknown
- 1981-05-20 PL PL1981231271A patent/PL134458B1/en unknown
- 1981-05-20 BR BR8103139A patent/BR8103139A/en not_active IP Right Cessation
- 1981-05-20 EG EG283/81A patent/EG15440A/en active
- 1981-05-20 DD DD81230122A patent/DD159040A5/en not_active IP Right Cessation
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2504909A1 (en) * | 1981-05-04 | 1982-11-05 | Gattys Ing Buero F J | PROCESS FOR THE STABILIZATION OF DEHYDRATED MAGNESIUM CHLORIDE AGAINST RE-HYDRATION |
| WO1995021689A1 (en) * | 1994-02-11 | 1995-08-17 | Incitec Ltd. | Granular urea |
| AU679330B2 (en) * | 1994-02-11 | 1997-06-26 | Incitec Ltd | Granular urea |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732 | Registration of transactions, instruments or events in the register (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19930515 |