WO1997032831A1

WO1997032831A1 - A process for manufacturing a fertilizer having a blend of constituents

Info

Publication number: WO1997032831A1
Application number: PCT/US1997/004355
Authority: WO
Inventors: Peter A. C. Chown
Original assignee: Monsanto Company
Priority date: 1996-03-05
Filing date: 1997-03-05
Publication date: 1997-09-12
Also published as: GB9604685D0; AU2217097A

Abstract

A solid fertilizer blend block has a substantially homogenous composition. The block is made by a process which comprises providing the constituents in a dry form, providing a filler material which is in a dry form and which is such that it hardens after admixture with water, mixing together the dry constituents and the dry filler material to form dry mixture, adding water to the dry mixture to form a wet mixture, introducing the wet mixture into a mold, hardening the wet mixture in the mold to form a molded block, removing the molded block from the mold, and drying the molded block to harden it further. The process is carried out in shaped molds made of cardboard, metal or plastic. The fertilizer blend is applied onto or into the soil by gradually removing the fertilizer blend material from the surface of the molded block by scraping or shaving it.

Description

A PROCESS FOR MANUFACTURING A FERTILIZER HAVING A BLEND OF CONSTITUENTS

FIELD OF THE INVENTION

This invention relates to a molded fertilizer block having a blend of constituents, to an apparatus and a process for manufacturing such block and to applying the fertilizer blend to the soil. BACKGROUND OF THE INVENTION

The known manufacture of blended fertilizers gives rise to a number of problems. For example, when transporting blended fertilizers, larger particles in the blended fertilizers tend to congregate together, thereby upsetting a balanced blend in the fertilizers. This in turn means that a balanced blend is not available for use and the fertilizer may contain substantially non-blended constituents in excessive concentrations. The constituents may be pure fertilizers or they may be materials such for example as pesticides, fungicides and insecticides.

Another problem of manufacturing known fertilizers having a blend of constituents is that some of the constituents can often present a health hazard. This may be because the constituents give rise to the formation of dust which can be inhaled, or because the constituents are poisonous or toxic to workers manufacturing the fertilizer. Where the known fertilizers having a blend of constituents are in granular form, it often occurs that the granules form large clusters when moisture is picked up during storage. This can present a major problem when spreading the known fertilizers by spreading machines since the large clusters tend to block up the spreading machines.

When spreading fertilizers from large machines for agricultural and horticultural purposes, granulated fertilizers having a blend of constituents can cause further problems insofar as the granules are usually of different sizes and weight. For those spreading machines that work on the principle of a rotating disc which throws out the granules, for example from either side of a tractor, then some granules will be thrown further than other granules because of the weight difference between the granules. The weight difference may be due to different sizes of granules or, alternatively, the weight difference may be due to certain granules within the blend having constituents which weigh more heavily than other constituents. For example, iron phosphate trace element constituents weigh more heavily than urea trace elements. Where a granulated fertilizer having a blend of constituents is not evenly distributed on the ground, then it will be apparent that plant life may be adversely affected by too little or too much or certain constituents within the fertilizer. For example, if there are too many nitrogen-based granules in one area, this may result in burning of grass if grassland is being fertilized.

Similarly, plants may be under nourished if they do not receive the required proportion of designated constituents.

An object of the present invention to obviate or reduce the above-mentioned problems.

Other objects of the present invention will become apparent to those skilled in the art upon studying the art upon studying this disclosure.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, a process for manufacturing a fertilizer having a blend of constituents includes the following steps.

First, fertilizer constituents in a dry form, a binder and optimally a filler material are mixed together to form a dry mixture. Water is then added to the dry mixture to form a wet mixture. The wet mixture is introduced into a mold where it is permitted to harden forming a molded block. The molded block is removed from the mold. The molded block then is dried to harden it further.

In accordance with another aspect of the present invention, a shaped mold for a fertilizer blend includes a lateral, preferably cylindrical wall, an end wall. The end wall preferably accommodates a shaft which extends in the center parallel to the lateral wall.

The shaft is made of a rigid material, such as metal, plastic or wood. The mold can be made of any rigid material which will retain the desired shape when the mold is filled with the wet fertilizer blend.

In accordance with a further aspect of the present invention, a method of applying a molded fertilizer blend involves abrading, grading, or shaving the surface of the mold to produce blended particulates and spreading the blended particulates onto or into the soil.

Other aspects of the present invention will become apparent to those skilled in the art upon studying this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made to the accompanying drawings which are given by way of example only and in which:

Figure 1 is a perspective view of a first apparatus for dispensing fertilizer from a molded block made in accordance with the process of the present invention;

Figure 2 is a side elevational view of second apparatus for dispensing fertilizer from a molded block made in accordance with the present invention;

Figure 3 is a perspective view of part of the apparatus shown in Figure 2; Figure 4 is an end view of part of third apparatus for dispensing fertilizer from a block made in accordance with the present invention;

Figure 5 is a plan view of the apparatus shown in Figure 4; Figure 6 shows fourth apparatus for dispensing fertilizer from a block made in accordance with the present invention;

Figure 7 shows firth apparatus for dispensing fertilizer from a block made in accordance with the invention;

Figure 8 shows a first mold for use in the process of the invention; and Figure 9 shows a second mold for use in the process of the invention. DETAILED DESCRIPTION OF THE INVENTION

It has been discovered that a fertilizer blend can be uniformly and efficiently applied to the soil by first forming a homogenous mixture of the fertilizer blend into a molded block and then producing particles from the block by scraping, shaving or grating its surface. The term "fertilizer blend" as used herein includes not only fertilizers but also other nutrients, trace elements, pesticides, fungicides, herbicides and insecticides. The molded block is formed using a fertilizer blend, a filler, a binder and water.

In some cases the same material may serve as a filler and a binder. For example, charcoal may serve both purposes.

The process of the invention may be one in which the blend of constituents includes different types of fertilizer. Any suitable and appropriate types of fertilizers can be blended together in any suitable and appropriate proportions and amounts. The blend may also include nutrients, trace elements and/or one or more of pesticides, fungicides and insecticides. The binder may be any suitable and appropriate inorganic or organic material, which is able to harden after being contacted with water. The preferred filler may be, for example, a clay. Preferably, the binder is gypsum. The reason gypsum is preferred is that it is capable of setting the blend without heat. Fillers can include wood flower, charcoal, seaweed powder and bone meal.

Usually the wet mixture will be formed in a mixing vessel. The mixing vessel may be of any suitable and appropriate size and construction. The water which is added to the blend may contain constituents for the fertilizer, i.e. dissolved or suspended fertilizer compounds or elements. Preferably, the process is one in which the wet mixture in the mold is hardened to form the molded block by allowing the filler to absorb the water in the wet mixture. If desired, external heat may be applied.

The mold is preferably of a circular or square cross sectional shape. Other cross sectional shapes may however be employed for the mold. The mold can be made from cardboard, plastic, metal or any other rigid material that will retain the shape of the mold during processing. Cardboard is preferred because it is inexpensive and easy to remove from the solid block.

Preferably, the molded block is further dried after removal from the mold. The drying may be effected using air, preferably hot air. The drying may alternatively be effected using a hot oven.

Fertilizer blocks produced according to the process of the present invention can be utilized in various ways as mentioned herein below.

A round fertilizer block can be rotated against means such for example as knives or serrations in order to produce granules of required size. If the block is a flat sided block, then the block can be reciprocated backwards and forwards over knives or serrations in order to provide the granules. The granules can be allowed to fall on to the land as they are produced or, alternatively, they can be fed on to a conveyor belt for storing for subsequent use.

Granules formed from a block of fertilizer can be given a hardening treatment to ensure that the granules stay hard and can be packed and transported without the blend being altered. If desired, a very fine cutter can be used to produce a very fine power which can then be placed in a rotating container. Water can be re-added to manufacture a very fine round granule that can then be dried, for example by hot air or in an oven, ensuring that the granule has an equally distributed blend of constituents throughout. Blocks of round fertilizer can be transported directly to farms where they can be granulated by appropriate granulating machinery on the rear of tractors.

For domestic use, the blocks of fertilizer may be granulated by hand using, for example, a grater.

For domestic, horticultural and agricultural use, appropriately sized blocks of the fertilizer can be made to place around or adjacent plants and shrubs. The blocks can then slowly release the fertilizer as they break down. If desired fertilizer blocks or granules produced from fertilizer blocks can be dissolved in water to form a liquid fertilizer for appropriate distribution.

The molded blocks may be in the form of collars for placing around trees or shrubs. If desired, the collars may be held together by using a coarse plastics material such for example as SCOTCH-BRITE®.

If desired, fertilizer blocks having different blends of constituents can be color coded. The color coding can be effected by providing the fertilizer blocks with different color dyes according to different blends of constituents. The dyes may be, for example, food dyes.

The blend of constituents may include organic materials such for example as blood, fishmeal and seaweed extract. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to Figure 1, there is shown first apparatus in the form of a grater 2 having serrated apertures 4. When a block 6 of fertilizer produced by the process of the present invention is rubbed over the grater 2, granules 8 are generated. The grater 2 is intended for hand use for dispensing the fertilizer in the form of the granules 8 around plants and small shrubs.

Figure 2 shows second apparatus in the form of a hand-operated trolley 10 for dispensing fertilizer from a block 12 or fertilizer of circular cross section. As can be seen, the block 12 is supported between three rollers 14. 16, 18. The rollers 14, 16, 18 are mounted on two side plates 20, 22 which form a frame. The side plates 20, 22 also support a pair of wheels 24, 26 and a handle 28. The handle 28 is pushing or pulling the trolley 10 over ground to be fertilized. As the trolley is pushed or pulled, the block 12 rotates and it rotates against a knife blade 30 which cuts granules off the circumference of the block 12. The knife blade 30 may alternatively be other cutter means including a grater.

Figure 4 shows a somewhat similar arrangement to that shown in Figure 2.

Similar parts have been given the same reference numerals for ease of comparison and understanding. In Figure 4, a line of blocks are employed and they are mounted on the back of a tractor 32. The line of blocks 12 is shown in Figure 5. The knife blade 30 or other cutter means extends the entire length of the blocks 12 as shown in Figure 5. The rollers 14, 16, 18 rotate faster or slower in dependence upon the speed of the tractor 32, thereby to generate more or less granules of fertilizer from the blocks 12.

Referring to Figure 6, there is shown fourth apparatus in which a serrated edge device 34 removes particles from a block 36 of fertilizer produced by the process of the present invention. The block 36 is mounted for rotation on a shaft 38. The block 38 is supported by a pair of support rollers 40, 42. Granules 44 removed from the block 36 pass along a conveyor belt 46 where they can be stored or further treated as may be desired.

Figure 7 shows fifth apparatus which utilizes a large grater 48 which is able to reciprocate backwards and forwards by virtue of being connected to a reciprocating arm

50. Granules 52 are generated from a large fertilizer block 54 produced in accordance with the process of the present invention.

Figure 8 shows a mold 56 of circular cross section. In the process of the invention, a wet mixture of the blend of constituents of the fertilizer and the filler material passes along pipe 58 and into the mold 56. The mold 56 has a central tube 60 which means that the produced block of fertilizer has an axial bore for receiving a shaft such for example as the shaft 38 shown in Figure 6.

Figure 9 shows a mold 62 of square cross sectional shape. The mold 62 has means 64 for enabling the mold 62 to be opened and closed. It is to be appreciated that the Examples and the drawings have been given for illustrative purposes only and that modifications may be made. In order to facilitate a full and complete understanding of the present invention, reference will now be made to the following Examples. The following examples are provided for illustrative purposes and are not intended to limit the scope of the present invention. Example 1

A blend of fertilizers, trace elements, pesticides, fungicides and insecticides were blended together in dry form with dry gypsum which acted as a filler. The constituents for the fertilizer and the gypsum were mixed together as a dry powder and the dry powder was then placed in a mixing vessel. Water was added to form a wet mixture. The wet mixture was poured into a mold having circular cross sectional shape and a center tube. The gypsum caused the wet mixture to hydrate and dry within 10-15 minutes to form a molded block. The molded block was removed from the mold and air dried to further harden the molded block.

The finished molded block was a block of fertilizer having a desired blend of constituents which were such that the composition of the blend could not be altered during transportation. Still further, the fertilizer block was safe and easy to handle even although it contained pesticides, fungicides and insecticides which in themselves are often harmful to handle. Also the molded fertilizer block did not provide any dust for causing injury by inhalation. Example 2

The process of Example 1 was repeated except that the water contained some constituents for the fertilizer, the wet mixture was poured into a mold having a square cross sectional shape, and the molded block that was removed from the mold was dried in a hot oven instead of being air dried. The formed fertilizer block was found to have all of the advantages that the fertilizer block of Example 1 had.

Example 3 The following procedure was used to make four molded blocks of the present invention. Dry ingredients of the following formulations were mixed in a ribbon blender. Enough water was then added to convert the mixture into a pourable slurry. Generally, the amount of water was in the range from about 250 ml to 275 ml per kilogram of dry blend. A setting agent in the form of gypsum was then added to the slurry and the resulting blend was thoroughly mixed. The blend was then poured into a cardboard mold and allowed to solidify. The solidification was completed in about 15 to 20 minutes.

(1) (2) (3) (4)

Ingredient Amount Amount Amount Amount

Urea 46 354 469 361 361

MAP - Muriate of Potash 50 50 50 50

Pot Nit - Potassium Nitrate 66 66 66 66

FeS0₄ 300 200 300 300

Dye 0 0 0 1

Gypsum 200 200 200 199

Iron Phosphate (22mls) 30 (l lmls) 15 (16mls) 23 (16mls) 23 l OOOg lOOOg lOOOg lOOOg

Analysis for

N-P205-K20 17.5-3-3 +6Fe 23-3-3 +4Fe 18-3-3 +6Fe 18-3-3 +6Fe

The fertilizer blend can be applied to the soil at the following rates: Application rate 35g/m2 70g m2 52g/m2 52g/m2

The weights of blocks needed for a 100 square meters of soil were calculated to be as follows: Weight needed for 100 m₂ 3.5kg 7.0kg 5.25kg 5.25kg

Many changes and modifications will occur to those skilled in the art upon studying this disclosure. All such changes and modifications are intended to be included in the invention defined by the following claims.

Claims

CLAIMS:

1. A process for manufacturing a fertilizer blend having a plurality of constituents, which process comprises the following steps: providing the constituents in a dry form, providing a binder which is in a dry form and which is such that it hardens after admixture with water, mixing together the dry constituents and the dry filler material to form a dry mixture, adding water to the dry mixture to form a wet mixture, introducing the wet mixture into a mold, hardening the wet mixture into the mold to form a molded block, removing the molded block from the mold, and drying the molded block to harden it further.

2. A process according to claim 1 in which the blend of constituents includes different types of fertilizers.

3. A process according to claim 2 in which the blend of constituents includes trace elements.

4. A process according to claim 2 in which the blend of constituents includes one or more of pesticides, fungicides, herbicides and insecticides.

5. A process according to claim 1 in which the binder is gypsum.

6. A process according to claim 1 in which the wet mixture is formed in a mixing vessel.

7. A process according to claim 1 in which the water contains constituents for the fertilizer.

8. A process according to claim 1 in which the wet mixture in the mold is hardened to form the molded block by allowing the filler to absorb the water in the wet mixture.

9. A process according to claim 1 in which the molded block is dried.

10. A process according to claim 9 in which the drying is effected using hot air.

1 1. A process according to claim 9 in which the drying is effected using a hot oven.

12. A process according to claim 1 further comprising a step of drying the molded block after the removing step.

13. A substantially homogeneous fertilizer blend comprising: a fertilizer blend constituents and a binder, said constituents being substantially uniformly thoughout the block.

14. A method of applying a fertilizer blend to the soil comprising the following steps: producing a substantially homogenous molded block of a fertilizer blend; 10 removing the material from the surface of the block, and applying the removed material to the soil.

15. A mold for receiving a fertilizer blend, slurry, said mold comprising; a lateral wall; an end wall; and a tubular member extending through the mold parallel to the lateral wall.

16. The mold according to claim 15 wherein the tubular member is a tube and wherein said tube is rigidly attached to the end wall.