Chemistry: fertilizers – Processes and products – Organic material-containing
Reexamination Certificate
1999-05-25
2001-05-15
Langel, Wayne (Department: 1754)
Chemistry: fertilizers
Processes and products
Organic material-containing
C516S077000, C516S079000
Reexamination Certificate
active
06231632
ABSTRACT:
TECHNICAL FIELD
This invention generally relates to a urea processing agent useful in making particulate urea compositions and fertilizer compositions, and methods of making the urea compositions and fertilizer compositions.
BACKGROUND OF THE INVENTION
Urea is a leading source of solid form nitrogen in the fertilizer industry. This is because there are a number of advantages associated with urea over other fertilizers such as ammonium nitrate. In particular, urea has a high plant nutrient analysis. Urea is classified as a nonhazardous material whereas other fertilizers such as ammonium nitrate, under certain conditions, may be an explosive compound. Finally, environmental concerns such as minimizing air pollution are mitigated by using urea compared to many other fertilizers.
However, there are drawbacks associated with using urea as a fertilizer. When particulate urea is in the form of granules or prills, urea is highly friable due to relatively low hardness of the particles and prone to caking (prone to agglomeration). High friability is undesirable because the prills or granules tend to break into smaller particles, and produce substantial amounts of dust during handling, transportation, and application. Since urea products are often used in bulk blend fertilizer products, it is desirable for the urea to possess a predetermined, uniform size of granules to avoid unwanted segregation of the component products. If the urea product breaks into smaller particles, unwanted segregation of the urea may occur. Moreover, it is desirable for the urea to possess high hardness since urea granular products may break down when introduced into modern, rotating turbine-fan type field distribution equipment commonly used today. The breakdown of urea granules results in uneven distribution of the fertilizer from such equipment. And dusting is another undesirable consequence of relative low hardness.
Another concern with urea products is caking or agglomeration. Urea products are frequently transported, sold and used in large volumes and are thus transported and stored in bulk form. Because of the tendency for urea to cake or agglomerate, storage and transportation is not feasible without additional processing considerations that significantly add to the costs of production and/or handling. Furthermore, any additional processing must not involve undesirable reactions with the urea or raw materials used to make urea.
Attempts have been made to address these concerns. For example, it is known to incorporate formaldehyde and/or lignosulfonates into either the urea synthesis stream or the anhydrous molten urea melt stream. However, the use of formaldehyde is disfavored because it presents serious health and safety considerations. And the use of lignosulfonates can discolor the urea product to an unaesthetic brownish hue, with the result that the product is not well accepted in the marketplace.
The addition of a gelling type channelized 2:1 clay such as attapulgite or sepiolite to the urea melt stream or the urea synthesis stream is also known. Urea made with attapulgite or sepiolite has certain undesirable characteristics including color and increased agglomeration. Environmentally friendly urea products having increased hardness and increased resistance to agglomeration are desired.
SUMMARY OF THE INVENTION
In one embodiment, the present invention relates to a particulate urea composition containing particulate urea; kaolin; and a dispersant, wherein the dispersant is at least one of ammonia based dispersants, sulfonate dispersants, carboxylic acid dispersants and polymeric dispersants.
In another embodiment, the present invention relates to a method of making urea, involving the steps of contacting a urea process stream with a slurry comprising a liquid, kaolin, and a dispersant, wherein the dispersant is at least one of ammonia based dispersants, sulfonate dispersants, carboxylic acid dispersants and polymeric dispersants; and recovering urea.
In yet another embodiment, the present invention relates to method of making fertilizer, involving combining a particulate urea composition comprising particulate urea, kaolin, and a dispersant, wherein the dispersant is at least one of ammonia based dispersants, sulfonate dispersants, carboxylic acid dispersants and polymeric dispersants, with a fertilizer material to provide a fertilizer.
The present invention relates to an improved urea particulate compositions useful for direct application to the soil, as an intermediate product for the subsequent incorporation with other fertilizer materials into solid bulk blends, or in any application facilitated by the use of high hardness and/or anti-caking urea particulate compositions. The urea particulate compositions of the present invention have improved anticaking and nonfriable characteristics which render it superior to urea fertilizer granules produced by incorporation of gelling type 2:1 clays into an urea synthesis liquor.
REFERENCES:
patent: 3186828 (1965-06-01), Baarson et al.
patent: 3234004 (1966-02-01), Smith et al.
patent: 3686305 (1972-08-01), Otsuka et al.
patent: 3690931 (1972-09-01), Jasnosz, Jr.
patent: 3697245 (1972-10-01), Dilday
patent: 4301299 (1981-11-01), Inoue et al.
patent: 4670588 (1987-06-01), Zardi
patent: 4864059 (1989-09-01), Fujii
patent: 4885021 (1989-12-01), Elrod et al.
patent: 4988377 (1991-01-01), Manalastas et al.
patent: 5403956 (1995-04-01), Pagani
patent: 5622658 (1997-04-01), Lloyd et al.
patent: 5628813 (1997-05-01), Chen et al.
patent: 5676729 (1997-10-01), Elrod et al.
patent: 5767313 (1998-06-01), Jonckers
patent: 5782951 (1998-07-01), Aylen et al.
patent: 5837651 (1998-11-01), Hill
patent: 3013616 (1980-09-01), None
patent: 0628527A1 (1993-07-01), None
patent: 998588 (1961-08-01), None
patent: 1109665 (1965-03-01), None
International Search Report (No Date).
Gruber Karen A.
Mamun Shireen A.
Engelhard Corporation
Keller Raymond F.
Langel Wayne
LandOfFree
Urea processing agent does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Urea processing agent, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Urea processing agent will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2498789