AU627438B2 - Granular ammonium sulphate and process for the production thereof - Google Patents

Description

a OPI DATE 01/06/89 APPLN- I D 26011 88

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Li 6 7 IA 8 wo'AOJP DATE 06/07/89 PCT NUMBER PCT/AU88/00422 TENATINAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (51) International Patent Classification 4 (11) International Publication Number: WO 89/ 04291 C0C 1/242, 1/24, B01J 2/30 Al (43) International Publication Date: 18 May 1989 (18.05.89) (21) International Application Number: PCT/AU88/00422 (81) Designated States: AT (European patent), AU, BE (European patent), CH (European patent), DE (Euro- (22) International Filing Date: 28 October 1988 (28.10.88) pean patent), FR (European patent), GB (European patent), IT (European patent), JP, LU (European patent), NL (European patent), SE (European patent), (31) Priority Application Number: 115,920 SU.

(32) Priority Date: 2 November 1987 (02.11.87) Published (33) Priority Country: US With international search report.

(71) Applicant: RETEC LTD [AU/AU]; Paringa Road, Gibson Island, Murarrie, Brisbane, QLD 4000 (AU).

(72) Inventors: FISCHBEIN, Milton 10710-135 Street, Edmonton, Alberta T5M lJo BROWN, Anthony, Martin 9 Doheny Street, Mt. Gravatt, QLD 4122

(AU).

(74) Agent: GRANT ADAMS COMPANY; 333 Adelaide Street, Brisbane, QLD 4000 (AU).

(54) Title: GRANULAR AMMONIUM SULPHATE AND PROCESS FOR THE PRODUCTION THEREOF (57) Abstract A method for producing ammonium sulphate granules of exceptional size, hardness, and uniformity, which moreover are free-flowing and non-caking. The method may include producing the granules to have a pH within a specified range, using a granulating aid, and cooling the granules after drying and screening but prior to storage. Ammonium sulphate granules, of exceptional size and hardness, having a pH within a specified range, which are free-flowing and non caking.

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WO 89/04291 PCT/AU88/00422 TITLE: GRANULAR AMMONIUM SULPHATE AND PROCESS FOR THE PRODUCTION THEREOF BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

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The present invention relates to a process for the production of granular ammonium sulphate, and to the granular amtmoniumn sulphate produced by that process.

More specifically, the present invention relates to a granular ammnoniumn sulphate, and to a process for its production, that has an exceptional size and hardness and that ramains free-flowing and substantially free from caking during storage.

DESCRIPTION OF BACKGROUND AN]) RELEVANT MATERIALS Ammonium sulphate has a number of important applications, with perhaps the chief among these being agricultural f ertilization. In this capacity ammuonium sulphate provides a ready source of nitrogen and sulphur, which are critical crop nutrients.

Ammonium s".lphate may be produced in a number of ways, including as a by-product of other industries For example, ammonium sulphate is commonly crystallized from solutions produced as a by-product f rom coke ovens and caprolactum plants. The production of ammoniumi sulphate per se, rather than as an incidental by-product, generally involves combining axmmonia with sulphuric acid, which results in amrmonium sulphate having a crystalline structure.

Ammonium sulphate is often not used as a fertilizer by itself, but rather in combination with other vital plant nutrients. Therefore, in commercial use ammonium WO 89/04291 PCT/AU88/00 4 2 2 2 sulphate must often be blended with granular fertilizers to produce a balanced fertilizer blend.

Unfortunately, crystalline ammnonium sulphate suffers f rom serious drawbacks which impede its incorporation into fertilizer blends, and which even impair its use as a f ertilizer per se. Chief among these drawbac! s are small particle size; nonuniform particle size; and an inability to flow freely. These physical properties make it quite difficult to produce fertilizer blends containing ammonium sulphate in which the several constituents are uniformly distributed, which is of course important in achieving optimum results when the fertilizer is spread, and which also facilitates the mechanical ease and efficiency of the spreading process.

Even on those occasions when amm~onium sulphate is used by itself, the lack of uniformity in particle size causes dif ficulties in the spreading process and leads to uneven results.

Attempts have been made to overcome these drawbacks by modifying the crystallization processes, for example by using counter-current crystallization. In a conventional crystallization process, crystalline ammonium sulphate particles growing by evaporation in vacuum crystallizers move in numerous steps from hotter stages to cooler -stages. In the counter-current process, the fine crystals formed during a cooler stage I are led to the next hotter stage, where they are mixed with an evaporatiiig hot solution. Here the cooler crystals serve as nuclei for the formation of crystals from the oversaturated solution resulting from evaporation of the previous (hotter) stage.

Counter-current crystallization sugg~zz s from the disadvantage that fuel usage and maintenance costs in WO 89/04291 PcT/AU88/00422 3 Sthe dissolution and recrystallization phases are relatively high, and lead to higher production costs.

In addition, there are difficulties with recovering I and/or recycling the ammonium sulphate fines left over from processing operations such as screening. Moreover, the ammonium sulphate produced by recovery and recycling of the fines is formed of particles which are angular v and irregular in shape. In order to have good commercial utility, ammonium sulphate particles should j 10 have a rounded shape and be of a uniform size.

There is a long history of processes for the production of ammonium sulphate, and of attempts to improve on the shape, size, uniformity, and storage characteristics of ammonium sulphate either by modification of crystallization procedures or by the use of granulating techniques; ADAM et al., U.S. Patent 1,919,707, is directed to a method for the crystallization of ammonium sulphate in the form of elongated crystals that have a high proportion of voids in bulk, which is asserted to prevent caking. The high proportion of voids is said to follow from the elongated shape of the crystals, which is caused in turn by including a metallic salt, such as an iron, chromium, aluminium, titanium, beryllium, zirconium, or yttrium salt, in the sulphuric acid which is reacted with a stream of ammoniacal gas to form the ammonium sulphate crystals.

i BERKHOFF, U.S. Patent 2,102,107, is directed to a method of obtaining coarse-grained crystalline ammonium sulphate by adding, to a sulphuric acid liquor used to produce ammonium sulphate crystals, a phosphatic compound such as phosphoric acid or a phosphate. The phosphatic compound is stated to aid in the production

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a1 PCT/A U88/00 422 WO 89/0429 1 of coarse-grained cytlbypeitangotmetallic SIMMS, U.S. Patent 2,656,248, is directed to an improved method for operating a plurality of evaporative amtmonium sulphate crystallization units by maintaining the pH- of the ammonium sulphate mother liquor in each unit within an optimum range. This optimum range is stated to be from about 1.5 to 2.5 (see column 2, lines 30-34).

COSTOLOW, U.S. Patent 2,782,097, is directed to a method for expanding the "metastable" region of an I ammonium sulphate solution in a continuous evaporative 15 crystallizer in order to avoid the formation of fines in the crystallizer. This expansion is accomplished by adding, to the ammonium sulphate mother liquor, soluble salts of chromium, iron, and aluminium. The crystallizer is preferably operated at a pH of less than 6, pref erably in the range of 2 to 3 (see column 2, lines 4-6 and column 3, lines 50-52).

WILSON, U.S. Patent 3,035,899, is directed to production of granulated ammonium sulphate by contacting a sulphuric acid mixture with ammonia in a turbulent zone,. such as a mixing T, to foarm an ammuonium sulphate slurry which is then passed to a heated rotating contacting zone containing recycled product.

BURNS, U.S. Patent 3,351,455 is directed to a dry process for preparing granular amnmoniumi sulphate by contacting recirculated undersize product granules with a mixture of sulphuric acid and ammonia in a granulator.

The undersize granules are coated with the reaction mixture product, dried, and screened. The process disclosed by BURNS must be conducted with a granulator WO 89/04291 WO 8904291PCT/AU88/00422 Veffluent stream bulk pH of less than 2.5; if the pH equals or exceeds 2.5, product- size decreases so drastically as to require plant shutdown due to plugging Ii of equipment with dust and fine particles (see column 3, lines 24-35, and Example 2 at column5, line 56 through column 6, line 2).

HICKS, U.S. Patent 3,464,809, is directed to a process for the production of granular ammoniumn sulphate by partially ammoniating sulphuric acid in a V preneutralizer vessel and introducing the resulting ammnonium sulphate solution into a granulator containing a bed of recycled fines. The onsize product of HICKS is variously shown as having a pH of 1.9, 1.8 (both from Table II in column or 3.8 (see Table III, at column BLACKNORE, U.S. Patent 3,725,029, is directed to a method for granulating by-product ammnonium sulphate in a drum granulator, using a concentrated lignosulphonate solution as a binder. The resulting particles are cooled, coated with urea, and then coated with a dry powder in order to prevent caking of the product, which would otherwise occur when the product was allowed to stand during storage.

BARBER, U.S. Patent 3,738,821, is directed to a method f or agglomerating or pelletizing ammonium sulphate, by adding phosphoric acid to an aqueous solution of ammnoniumn sulphate which includes free ammnonia. This method is practiced in a fluid bed apparatus.

BECHT1{OLD et al., U.S. Patent 4,305,748, is directed to a process for granulating or7 pelletizing ammnonium sulphate by rapidly drying dissolved ammonium WO 89/04291 6 sulphate, and placing the granulating or pelletizing a thereto a fine spray of water.

PCT/AU88/00 4 2 2 mmonium sulphate in a pparatus while adding .1

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HARRISON et al., U.S. Patent 4,589,904, is directed to a process for the granulation of crystalline byproduct ammonium sulphate. Separate streams of sulphuric acid, ammonium sulphate solution, and gaseous anhydrous ammonia are introduced beneath the surface and near the centre of a rolling granulation bed of crystalline by-product ammonium sulphate in recycle material. This produces fresh ammonium sulphate, which is asserted to precipitate and to bind the crystals together. Mention is made of the optional use of a granulating aid, such as alum (see column 5, lines 12- 17). The ammonium sulphate produced by the process of HARRISON et al. is stated to have a crush strength of up to 5.0 pounds, whereas it is stated that a crush strength of 3.0 pounds is considered acceptable in the industry (see column 8, lines 65-68).

The process described by HICKS avoids the involvement of crystalline ammonium sulphate in the granulation process, with some corresponding improvement in the shape and consistency of size of the resulting granules.

However, the percent recovery of onsize product by HICKS is quite low; for example, Table III of the HICKS patent, in column 11, lines 13-35, demonstrates that only 85.4% of the product falls within the -6 +10 mesh size range. In addition, those of ordinary skill in the art would expect the granular ammonium sulphate produced by HICKS to be of mediocre hardness, which is a serious drawback in handling and processing the granules.

This expectation is confirmed in an article by HICKS et al., 17 Agr. Food Chem. 306-311 (1969). In

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1 _I _i_ WVO 89/04291 PCT/AU88/00422 7 characterising the physical and chemical properties of granules produced according to a process substantially identical to that disclosed in U.S. Patent 3,464,809, the authors state that after being stored at relative humidity at 86 0 F for 96 hours, the granules are "fairly firm under finger pressure." This description, while difficult to compare with more quantitative parameters, indicates that granular ammonium sulphate produced according to the HICKS process is very substantially softer than granular ammonium sulphate produced according to the present invention, as will be discussed later.

One common method of granulation, as shown in the above references, is to use a rotary ammoniator granulator.

Another common method is to use a pugmill to contact recycle fines with varying proportions of ammonia and sulphuric acid, using granulation aids such as phosphates, ammonium nitrate, urea, or lignosulphates.

It has been found that these methods of granulating ammonium sulphate tend to produce a product which is not hard and free-flowing unless granulating aids are used in prohibitively expensive amounts.

These prior art drawbacks have been partially overcome rec.ent by the reen ddevelopment of a process for the production of granular ammonium sulphate, in which ammonium sulphate is granulated in the presence of a granulation aid which is an aluminium salt or a ferric salt. In this process, described in Australian Patent 492,758, ammonia and sulphuric acid are first mixed in a pipe reactor to form a slurry. The slurry is distributed onto a bed of ammonium sulphate fines, where further ammoniation occurs, and is then granulated in the presence of the aluminium salt or the ferric salt. The resulting product is free-flowing and non-caking; has a 4r WO 89/04291 PCT/AU88/00 4 22 8 1 pH of about 4.0 to 4.5, measured in a 10% solution (by weight in water); and has an average Pfizer hardness (as defined below) of about 5.0 pounds. The granulation may be carried out in a conventional apparatus, such as a rotary granulator or a pugmill.

As can be seen from the foregoing discussion there is an ammonium sulphate product pH range which has been closed to the prior art. Representative of the low end of the range are HARRISON et al., showing a possible product pH range of 1.80-2.60, a preferred range of 2.20-2.50, and actual Examples of 1.99-2.4; and BURNS, showing a product pH of less than 2.5, preferably of between 1.9 and 2.25. BURNS was unable to operate above a product pH of 2.5 because, as stated therein, at any higher pH dust and fines would form in such quantities as to force a plant shutdown.

Representative of the high side of the range is Australian Patent 492,758, which epeeratesy in a product pH range of 4.0-4.5. Based on Applicants' experience attempts to operate at a pH of lower than 4.0 using this process would result in granular ammonium sulphate which sets to a concrete mass during storage, and is thus quite unusable.

According to the present invention, the process for producing granular ammonium sulphate in the presence of an aluminium or ferric salt, as in Australian Patent 492,758, has been dramatically improved by conducting granulation within a pH range that was considered completely unusable by the prior art, followed by -rapid- cooling of the reulting granular-am-vmonium- sulphate. By discovering a technique for producing granular ammonium sulphate within this previously unappreciated pH range, Applicants have succeeded in making a product that far ONr ,v(i i i. \o .V 1 1- 1 WO 89/04291 PCT/AU88/00422 9 exceeds prior art granular, amminonium sulphate in size distribution as well as in hardness.

SUMMARY OF THE INVENTION The present invention is directed to a process f or producing free-f lowing, non-caking granular ammonium sulphate. The process, which involves adding a granulating aid to a slurry of amm~ronia and sulphuric acid, may be carried out under sufficiently acidic conditions to yield granular ammnoniumn sulphate with a pH of less than about 4.0; preferably of between about and 4.0; and most preferably of between about 2. 5 and 2.9, with an average pH of about 2.7.

The granulating aid may be a metal oxide or a salt of a metal hydroxide, such as aluminium oxide or sodium aluminate, or a metal salt, for example an aluminium salt or a f erric salt, preferably the sulphate salt.

Aluminium sulphate is most preferred.

The granulating aid is added to the slurry in an amount suffficient to yield amimonium sulphate granules comprising more than about 0.05 percent by weight of the metal. When the granulating aid is an aluminium salt, the amount of the aluminium salt added to the slurry is sufficient to produce anmonium sulphate granules having an aluminium content of between about 0.05% and 1.06% by weight; preferably of between about 0.15% and 1.06% by weight; and most preferably of between about 0.20% and 0.40% by weight.

The present invention also includes a composition of matt~er comprising amnmonium sulphate granules produced according to the method as described above.

W089/4291PCT/AU88/00422 In a further embodiment, the process may include cooling the anmmoniumi sulphate granules af ter granulating. The granules are cooled to a temperature of less than about 150 0 F; preferably to a temperature of between about 600 and 130 0 F; and most preferably to a temperature of between about 1100 and 130 0

F.

P The rate of cooling is generally greater than about 7.50 F/minute, preferably between about 9.5 and 16.50 F/minute, and most preferably between about 9.5 and 11.50 F/minute.

This cooling may be accomplished using any suitable means, such as a rotary cooler or a fluidized bed 415 cooler.

In the production of granular amnmonium sulphate according to the present invention, more than about 85.7% of the product ammnonium sulphate granules equal or exceed +10 Tyler mesh screen size; preferably more than about 95% of the product ammnoniumn sulphate granules *1equal or exceed +10 Tyler mesh screen size; and most preferably at least about 99% of the product ammoniumn sulphate granules equal or exceed +10 Tyler mesh screen process according to the present invention yields anmmoniumi sulphate granules having a Pf izer hardness of greater than about 5.0 pounds; preferably of greater than about 6.8 pounds; and most preferably at least about 9.8 pounds, with a usual hardness range of between about 9.8 and 12.7 pounds.

The present invention is further directed to a composition of matter comprising free-flowing, noncaking ammonium sulphate granules having a pH of less I i r WO 89/04291 PCT/AU88/00422 11 than about 4.0; preferably of between about 2.5 and and most preferably of between about 2.5 and 2.9, with an average pH of about 2.7.

The ammonium sulphate granules may comprise a metal selected from the group consisting of aluminium and iron. The granules preferably include aluminium as the metal, and have an aluminium content of more than about 0.05% by weight. The aluminium content is generally between about 0.05% and 1.06% by weight; preferably between about 0.15% and 1.06% by weight; and most preferably between about 0.20% and 0.40% by weight.

The ammonium sulphate granules may have a Pfizer hardness of greater than about 6.8 pounds; preferably, of at least about 9.8 pounds, and most preferably of between about 9.8 and 12.7 pounds.

In addition, more than about 85.7% of the ammonium sulphate granules equal or exceed +10 Tyler mesh screen size; preferably more than about 95% of the ammonium sulphate granules equal or exceed +10 Tyler mesh screen size; and most preferably at least about 99% of the ammonium sulphate granules equal or exceed +10 Tyler mesh screen size.

DESCRIPTION OF PREFERRED EMBODIMENTS Prior experience with varying the pH at which granulation of ammonium sulphate is carried out was thought to have established that there are certain pH values within which a commercially useful product cannot be made.

Assuming that excessive production of fines and dust does not require plant shutdown, granular ammonium SWO 89/04291 PCT/AU88/00422 12 sulphate produced at pH levels within this range can cake during storage, is not free-flowing, and can even set up into an adhered mass which will need to be broken apart with heavy machinery before it can be used.

It has now been discovered that this pH range can be exploited, producing a commercially valuable product of a hardness and uniformity of size unknown in the prior art. As a result of being able to operate within this range of pH, ammonium sulphate granules can be produced which are substantially larger and harder than :ior art ammonium sulphate granules, and the percentage of product ammonium sulphate granules that exceed +10 Tyler mesh is significantly greater than the prior art.

The process according to the present invention generally involves the formation of an ammonium sulphate slurry by mixing ammonia and sulphuric acid in a pipe reactor.

The ammonium sulphate slurry is introduced onto a bed of recycled ammonium sulphate fines, where further ammoniation takes place. Granulation is then carried out in the presence of a granulating aid, and the resulting product is dried, screened, and cooled. Any conventional granulating system may be used, including rotary granulators and pugmills.

The granulating aid may be a metal oxide, preferably hydrated, such as aluminium oxide; a salt of a metal Shydroxide, such as sodium aluminate; an aluminium salt; or a ferric salt. Aluminium salts are preferred, with aluminium sulphate being most preferred. Where. the granulating aid contains aluminium, the aluminium should be present in a soluble form.

The aluminium oxide granulating, aid is preferably used in the form of a slurry, while the aluminium or fer:.ic f i 1 O 89/04291 PCT/AU88/00422 I13 i| salt may conveniently be introduced to the ammonium sulphate slurry in the form of an aqueous solution.

Generally, the aqueous solution is introduced into the slurry in the pipe reactor. However, the aqueous solution may be metered into the granulation apparatus at any convenient location, such as adjacent the inlet thereof. Alternatively, the aluminium or ferric salt may be added to the granulator or to the recycle in I solid form, by means of a feeding apparatus.

Si0 Where an aluminium salt is used, it is generally used in an amount sufficient to give a final product containing more than about 0.05% by weight of aluminium.

Preferably the product contains between about 0.05 and 1.06% by weight of aluminium, even more preferably t| between about 0.15 and 1.06%, and most preferably the !I aluminium content is between a.-ut 0.25 and 0.40% by weight.

The product may contain phosphate derived from the starting materials or phosphate may be deliberately added. The presence of phosphate may favorably affect the granulation of the ammonium sulphate.

The process according to the present invention is conducted, at a pH sufficient to yield ammonium sulphate granules with a pH of less than about 4.0, measured in a solution, and the pH may be as low as about Granules produced according to the present invetnion and exhibiting a pH of between about 2.5 and 4.0 show no caking during storage, as initially indicated by performing accelerated caking tests on such granules.

100 gram samples of granular ammoniuir sulphate were placed in a stainless stee. tube with an outer diametrr of 2.0 inches. The samples wr.re pressurised to 35 psi,

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WO 89/04291 PCT/AU88/00422 14 using a pneumatic piston, and stored f or one week at a temperature of 85 0 F. The samples were then removed from the stainless steel tube and examined f or caking; no -4 caking was observed.

The accelerated caking tests were confirmed by a series of full-scale production runs producing ammoniumi sulphate granules having pH values of from 2.5-4.0. The granules were cooled in accordance with the present invention and stored in commercial-sized storage piles V of 400-10,000 tons.

Af ter several weeks of storage, -the product remained free-flowing and free from caking.

Atrleaving tedrying step tegranules aesree and cooled prior to storage. Without being bound by this theory, it is thought that the non-caking Ii properties of the low pH granules result from the rapid cooling of the granules, such as in a rotary cooler, generally from an initial temperature of about 225 0 F to a pre-storage temperature of about 120 0

F.

The rate of cooling is generally greater t.ian about 7.50 F/minute, preferably between about 9.5 and 16.50 F/minute, and most preferably between about 9.5 and 11.5* F/minute.

While the cooling 2should be rapid, any suitable means may be employed, including but not limited to a rotary cooler or a fluidised bed- cooler. The critical factor is not how the granules are cooled, but rather that they be cooled to a pre-storage temperature of less than about 150OF and preferably of between about 60 and 130*F, with a pre-storage temparature of between about 110 arnd 130*F being most preferred.

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WO 89/04291 PCT/AU88/00422 Granulated ammonium sulphate produced according to this process remains free-flowing and does not consolidate or set to a hard mass upon being allowed to stan(' in large piles during storage. In addition, the resulting ammonium sulphate granules are substantially harder than granular ammonium sulphate known to the prior art.

The hardness of the granules is measured with a i 10 commercial compression tester, such as a Chatillon compression tester. At least 25 granules within the Tyler mesh rize range of -7 +8 from a given product run are tested individually, and the average of these measurements is taken as the Pfizer hardness of the product run from which the tested granules were taken.

SThe granules are placed, one at a time, on a flat surface provided on the compression tester. Pressure is applied to each granule using a flat-end rod attached to the compression tester, and a guage mounted in the compression tester measures the pressure required to fracture the granule. Ammonium sulphate granules produced according to the process of the present invention generally possess a Pfizer hardness in the range of from 9.8 to 12.7 pounds, while prior art granular ammonium sulphate has typical Pfizer hardness values of 5 pounds or less.

Due to the superior size and hardness of the granules, ammoniut sulphate produced according to the present invention experiences minimal breakdown into undesireably small fragments during cooling, storage, handling, blending, shipping and spreading.

Moreover, use of granular ammonium sulphate produced according to the present invention, either as a fertilizer per se or as an ingredient in fertilizer H i .i I I WO 89/04291 PCT/AU88/00422 16 blends, produces exceptionally uniform results. This follows from the fact that the mechanics of spreading fertilizer are improved by use of a physically more uniform product, resulting in more uniform spreading.

In addition, when fertilizer blends are used, blends using granular ammonium sulphate produced according to the present invention will remain uniformly blended, rather than tending to layer out by component by the time the end user is reached as is often the case with prior art blends.

It should be noted that in the process according to the present invention, ammonium sulphate fines produced therein are recycled through the granulation apparatus, where they are formed into the bed onto which the slurry containing ammonium sulphate is distributed. While the recycle ratio generally ranges from about 7:1 to 20:1, ratios as low as about 2.5:1 have been achieved.

The present invention may be further appreciated by Ireference to the following Examples. It is to be understood that these Examples are merely illustrative and in no way define or limit the scope of the present invention, which extends to any and all compositions, means, and methods suited for practice of the process according to the present invention, as well as to any and all products made thereby.

The following examples demonstrate production of anmmonium sulphate granules according to the present invention which, although produced with a low pH which results in larger and in harder granules, are freeflowing and non-caking: Ii 9- WO089/04291 PCT/AU88/00422 17 EXAMPLE 1 Granulation was conducted at a production rate of TPH. The pH of the resulting granular ammronium sulphate product ranged f rom about 2. 8 to 3. 1. The aluminium content of the resulting product ranged from about 0.31% to 0.36% by weight, and the average product temperature r exiting the cooler ranged from about 112 0 F to 130 0

F.

The product ranged in Pfizer hardness from about 9.8 to 12.7 pounds. Product size was between about 91.1 and 94.3%, on the Tyler mesh -6 +10 range, and did not cake during storage.

EXAMPLE II Granulation was conducted at a production rate of TPH. The pH of the resulting granular ammnonium sulphate product was about 2.9, and the aluminium content was about 0.27% by weight. The average product temperature exiting the cooler was about 93*F, and the product had a Pfizer hardness of about 10.1. About 93.3% of the product fell within the -6 +10 Tyler mesh range, and the 14 product did not cake during storage.

14 The following example demonstrates a typical cooling set-up for the pract ice of the process according to the 1425 present invention: EXAMPLE III Dried and screened granular amnmonium sulphate produced as in either Example I or Example II is introduced into a rotary drum cooler, counter to the air flow. Product entering the rotary cooler has a temperature of about 225*F, which has been reduced to about 120OF when product leaves the cooler. For a rotary cooler 30 feet long and 9 feet in diameter,, typical flow rates range .1i WO 89/04291 PCT/AU88/00422 from about 15 tne/hr to about 29 tne/hr, with a flow rate of about 25 tne/hr being typical.

EXAMPLE IV Granulation was conducted at a production rate of approximately 25 tonnes/hour over a 24-hour period.

Product exiting the cooler was determined to have a temperature of about 130 0 F, and was hard, free-flowing, and non-caking.

A 24-hour composite sample of the 600 tonnes of product produced during this run had the following chemical and physical properties: ii Ii~,

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Chemical Composition

N

S

H

2

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Al Weight 20.5 24.3 0.02 0.33 2.8 Product Size -10 Product Size +6 3.0 Product Size -6 +8 69.7 Product Size -8 +10 26.3 The following Tables exemplify the range of operating conditions by which the process according to the present invention may be practiced, but are not to be construed as in any way limiting. As may be clearly seen, the production of ammonium sulphate granules having a pH according to the process of the present invention yields a dramatic increase in hardness, which as previously demonstrated is not nullified by a loss of commercial utility through caking during storage.

i i i I i WO 89/04291 PCT/AU88/00422 19 TABLE 1 Summary of Product Quality and Operating Conditions For Granular Ammonium Sulphate Production Product pH 2.90 3.00 2.80 3.10 2.80 2.95 Product Aluminium 0.27 0.35 0.36 0.34 0.31 0.31 Cooler Outlet Temperature (Deg.F) 93 122 112 117 130 122 Pfizer Hardness (Pounds) 10.1 9.8 10.8 12.5 12.2 12.7 TABLE 1 (con't) Product Size -6+10 93.3 92.0 91.1 92.4 94.3 91.9 Product Size +6 2.2 5.0 4.1 4.8 3.0 2.9 Product Size -10 4.5 3.0 4.8 2.8 2.7 5.2 24 Hour Production

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594 594 334 384 582 532 If pr WO 89/04291 PCT/AU88/00422 TABLE 2 The following table demonstrates the outstanding onsize product yield attainable according to the present invention: Product Run +10 Total -6 +10 +6 1 98.4 92.2 6.2 2 99.0 96.0 3 98.0 93.8 4.2 4 98.0 91.6 6.4 5 98.0 91.1 6.9 TABLE 3 Correlation of Pfizer Hardness Verses Product pH Product Pfizer Sample Product Aluminium Hardness Number pH wt.) (Pounds) 1 4.3 0.28 6.7 2 4.30 0.29 6.9 3 3.80 0.36 7.7 4 4.60 0.39 9.3 4.10 N/A 9.2 6 3.20 N/A 8.3 7 2.90 N/A 10.1 8 3.00 0.35 9.8 9 2.80 0.36 10.8 3.10 0.34 12.5 11 2.80 0.31 12.2 12 2.95 0.31 12.7 13 4.80 0.32 8.8 30 14 4.00 0.39 7.8 Although the invention has been described with respect to the preferred embodiments discussed above, it is clearly understood that this is by way of example only, and that the invention is not limited to the particulars disclosed but extends to all equivalents within the scope of the claims.

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Claims (26)

1. A method for producing free-flowing, non- Scaking granular ammonium sulphate having a pH of between about 2.5 and 4.0 in the presence of a granulating aid, said method comprising the steps of: a) adding a granulating aid selected from the group consisting of a metal salt, a metal oxide, and a salt of a metal hydroxide, to a slurry of ammonia and sulphuric acid; and b) granulating said slurry to produce ammonium sulphate granules under sufficiently acidic conditions that said ammonium sulphate granules have a pH of between about 2.5 and

2. A composition of matter comprising ammonium sulphate granules produced according to the method as defined by claim 1.

3. The method as defined by claim 1, wherein said ammonium sulphate granules have a pH of between about and 2.9.

4. The method as defined by claim 3, wherein said ammonium sulphate granules have a pH of about 2.7. The method as defined by claim 1, wherein said granulating aid is added to said slurry in an amount sufficient to yield ammonium sulphate granules comprising more than about 0.05 percent by weight of said metal.

6. The method as defined by claim 5, wherein said metal is selected from the group consisting of iron and aluminium.

7. The method as defined by claim 5, wherein said granulating aid is selected from the group consisting of aluminium sulphate, ferric sulphate, aluminium oxide and sodium aluminate.

8. The method as defined by claim 5, wherein said granulating aid is an aluminium salt and further wherein the- amount of said aluminium salt added to said slurry I B WO 8904291PCT/AU88/00422 22 is suf ficient to produce arumonium sulphate granules U having an aluminium content of between about 0.05% and 1.06% by weight.

9. The method as defined by claim 8, wherein the amount of said aluminium salt added to said slurry is sufficient to produce axrmonium. sulphate granules having an aluminium content of between about 0.15% and 1.06% by weight. The method as def ined by claim 9, wherein the amount of said aluminium salt added to said slurry is sufficient to produce ammonium sulphate granules having an aluminium content of between about 0.20% and 0.40% by weight.

11. A method for producing free-flowing, non- caking granular ammoniumn sulphate having a pH of less than about 4. 0 in the presence of a granulating aid, said method comprising the steps of: a) adding a granulating aid selected from the group consisting of a metal salt, a metal oxide, and a salt of a metal hydroxide, to a slurry of ammonia and sulphuric acid, in an amount sufficient to yield ammonium sulphate granules comprising more than about 0.05 percent by weight of said metal; and b) granulating said slurry to produce ammonium sulphate granules under sufficiently acidic conditions 4 that said ammnonium sulphate granules have a pH of less than about

12. A composition of matter comprising ammnonium sulphate granules produced according to the method as defined by claim 11.

13. The method as def ined by claim 11, wherein said amnmonium sulphate granules have a pH of between about 2.5 and

14. The method as def ined by claim 13, wherein said 'ammonium sulphate granules have a pH of between about 2.5 and 2.9. WO 89/04291 PCT/AU88/00422 23 The method as defined by claim 14, wherein j Jsaid ammonium sulphate granules have a pH of about 2.7.

16. The method as defined by claim 11, wherein said metal is selected from the group consisting of iron and aluminium.

17. The method as defined by claim 11, wherein said granulating aid is selected from the group consisting of aluminium sulphate, ferric sulphate, aluminium oxide, and sodium aluminate.

18. The method as defined by claim 11, wherein I said granulating aid is an aluminium salt and further wherein the amount of said aluminium salt added to said slurry is sufficient to produce ammonium sulphate granules having an aluminium content of between about 0.05% and 1.06% by weight.

19. The method as defined by claim 18, wherein the i amount of said aluminium salt added to said slurry is i sufficient to produce ammonium sulphate granules having an aluminium content of between about 0.15% and 1.06% by weight. The method as defined by claim 19, wherein the amount of said aluminium salt added to said slurry is Vt sufficient to produce ammonium sulphate granules having an aluminium content of between about 0.20% and 4.0% by U 25 weight.

21. The method as defined by either claim 1 or claim 11, further comprising cooling said ammonium sulphate granules after granulating.

22. The method as defined by claim 21, wherein said ammonium sulphate granules are cooled to a temperature of less than about 150° F.

23. The method as defined by claim 22, wherein said ammonium sulphate granules are cooled to a temperature of between about 60 and 1300 F.

24. The method as defined by claim 23, wherein WO 89/04291__- PCT/AU88/00422 24 said ammoniumi sulphate granules are cooled to a temperature of between about 1100 and 1300 F The method as def ined by claim 21, wherein I said ammonium sulphate granules are cooled at a rate of greater than about 7.50 F/minute.

26. The method as defined by claim 25, wherein said amnmoniu~m sulphate granules are cooled at a rate of between about 9.5 and 16.50 F/minute.

27. The method as defined by claim 26, wherein 110 said ammoniumn sulphate granules are cooled at a rate of between about 9.5 and 11.50 F/minute..

28. The method as defined by claim 21, further comprising using a rotary cooler for said cooling.

129. The method as defined by claim 21, further 1 15 comprising using a fluidized bed for said cooling. The method as defined by either claim 1 or claim 11, wherein morc- than about 85.7% of said ammnoniumn 2 sulphate granules equal or exceed +10 Tyler mesh screc'n 4 size. 31. The method as defined by claim 30, wherein more than about 95% of said ammonium sulphate granules equal or exceed +10 Tyler mesh screen size. 32. The method as defined by claim 31, wherein at I least about 99% of said ammonium sulphate granules equal or exceed +10 Tyler mesh screen size. 33. The method as defi-ned by either claim 1 or claim 11, wherein said amimonium sulphate granules have a Pfizer hardness of greater than about 5.0 pounds. d34. The method as defined by claim 33, wherein said ammonium sulphate granules have a Pfizer hardness of greater than about 6.8 pounds. The method as defined by claim 34, wherein said ammnonium sulphate granules have a Pfizer hardness of at least about 9.8 pounds. 36. The method as defined by claim 35, wherein WO 89/04291 PTA8/02 PCT/AU88/00422 <I ~1I II 'I II said ammonium sulphate granules have a Pf izer hardness of between about 9.8 and. 12.7 pounds. 37. A method for producing free-flowing, non- caking granular amnmonium sulphate having a pH of less than about 4. 0 in the presence of a granulating aid, said method comprising the steps of: a) adding a granulating aid selected from the group consisting of a metal salt, a metal oxide, and a salt of a metal hydroxide, to a slurry of ammonia and sulphuric acid, in an amount sufficient to yield ammonium sulphate granules comprising more than about 0.05 percent by weight of said metal; b) granulating said slurry to produce ammoniumn sulphate granules under sufficiently acidic conditions that said ammnonium sulphate granules have a pH of less than about 4.0; and C) cooling said ammoniumn sulphate granules to a temperature of less than about 1500 F at a cooling rate of greater than about 7.50 F/minute, whereby more than about 85.7% of said ammnonium sulphate granules equal or exceed +10 Tyler mesh screen size and said amnmonium sulphate granules have a Pfizer hardness of greater than about 5.0 pounds. 38. The method as defined by claim 37, wherein the amount of said granulating aid added to said slurry is sufficient to yield ammonium sulphate granules comprising between about 0.05% and 1.06%, by weight, of s 1 aid metal; said ammonium sulphate granules have a pH of between about 2.5 and 4. 0; said ammonium sulphate granules are cooled to a temperature of between about 600 and 1300 F at a cooling rate of between about and 16.50 F/minute; said, ammonium sulphate granules have a Pfizer hardness of greater than about 9.8 pounds; and more than about 95% of said ammoniumn sulphate granules equal or exceed +10 Tyler mesh screen size. j WO 89/04291 PCT/AU88/00422 26 39. The method as defined by claim 38, wherein the amount of said granulating aid added to said slurry is sufficient to yield ammnoniumn sulphate granules comprising between about 0.20% and 0.40%, by weight, of said metal; said ammonium sulphate granules have a pH of between about 2.5 and 2.9; said amnmonium sulphate granules are cooled to a temperature of between about h 900 and 1300 'F at a cooling rate of between about and 11.50' F/minute; said ammnonium sulphate granules 1/10 have a Pfizer hardness of between about 9. 8 and 12.7 pounds; and at least about 99% of said amnmonium sulphate granules equal or exceed +10 Tyler mesh screen size. A composition of matter comprising free-- flowing, non-caking ammonium sulphate granules having a pH of between about 2.5 and 4.0, wherein said ammnonium I sulphate granules comprise a metal selected from the group consisting of aluminium and iron. 41. The composition of matter as defined by claim 40, wherein said ammonium sulphate granules have a pH of It betwreen about 2.5 and 2.9. 42. The composition of matter as defined by claim 41, wherein said ammonium sulphate granules have a pH of I about 2.7. 43. The composition of matter as defined by claim wherein said ammnonium sulphate granules have a V Pfizer hardL~ess of greater than about 6.8 pounds. 44. The composition of matter as defined by claim 43, wherein said ammoni'wn sulphate granules have a Pfizer hardness of atE least about 9.~8 pounds. The composition of matter as defined by claim 44, wherein said ammnonium sulphate granules have a Pfizer hardness o~f between about 9.8 and 12.7 po. ~S. 46. The omposition of matter as defined by claim 40, wherein said metal is aluminium. WO 89/04291 PCI'/AU88/00422 27 I 47. The composition of matter as defined by claim 46, wherein said ammonium sulphate granules have an aluminium content of greater than about 0. 05% by weight. 48. The composition of matter as defined by claim 47, wherein said ammonium sulphate granules have an aluminium, content o'f between about 0.05% and 1.06% by weight.

149. The composition of matter as defined by claim 48, wherein said ammoniumi sulphate granules have an aluminium content of between about 0.15% and 1.06% by weight. The composition of matter as def ined by claim 4 49, wherein said animon.Lum sulphate granules have an aluminium content of between a-bout 0.20% and 0.40% by weight. 51. The composition of matter as defined by claim wherein more than about 85.7% of said am~monium sulphate granules are equal to or larger than +10 Tyler mesh screen size. 52. The composition of matter as defined by claim 51, wherein more than about 95% of said granules are U equal to or larger than +10 Tyler mesh screen size. t53. The composition of matter as defined by claim 52, wherein at least about 99% of said granules are K equal to or larger than +10 Tyler mesh screen size. 54. A composition of matter comprising free- flowing, non-caking ammonium sulphate granules having a pH of less than about 4.0, wherein said ammonium sulphate granules. comprise more than about 0.05% by weight of a metal selected from the group consisting of aluminium and iron. The composition of matter as defined by claim 54, whcrein said ammonium sulphate granules have a pH of between about 2.5 and WO 89/04291 PCT/AU88/00422 28 56. The composition of matter as defined by claim wherein said ammonium sulphate cranules have a pH of between about 2.5 and 2.9. 57. The composition of matter as defined by claim 56, wherein said ammuonium sulphate granules have a pH of about 2'.7. 58. The composition of matter as defined by claim 54, wherein said ammonium sulphate granules have a Pfizer hardness of greater than about 6.8 pounds. 59. The composition of matter as defined by claim 58, wherein said ammonium sulphate granules have a Pfizer hardness of at least about 9.8 pounds. The composition of matter as defined by claim 59, wherein said ammonium sulphate granules have a Pfizer hardness of between about 9.8 and 12.7 pounds. 61. The composition of matter as def ined by claim 54, wherein said metal is, aluminium. 62. The composition of matter as def ined by claim 61, wherein said ammonium sulphate granules have an aluminium content of greater than about 0.05% by weight. 63. The composition of matter as def ined by claim 62, wherein said ammonium sulphate granules have an aluminium content of between about 0.05% and 1.06% by weight. 64. The composition of matter as def ined by claim 63, wherein said amnmonium sulphate granules have an aluminium content of between about 0.15% and 1.06% by weight. The composition of matter as defined by claim 64, wherein said ammonium sulphate granules have an aluminium content of between about. 0. 20% and 0. 40% by weight. 66. The composition of matter as def ined by claim 54, wherein more than about 85.7% of said eummonium sulphate granules are equal to or larger than +10 Tyler mesh screen size. WO089/04291 PCT/A1J88/00422 29 67. The composition of matter as defined by claim 66, wherein more than about 95% of said granules are equal to or larger than +10 Tyler mesh screen size. 68. The composition of matter as defined by claim 67, wherein at least about 99% of said granules are equal to or larger than +10 Tyler mesh screen size. 69. A composition of matter comprising free- flowing, non-caking ammonium sulphate granules wherein said ammonium sulphate granules have a Pfizer hardness 410 of greater than about 6.8 pounds. The composition of matter as defined by claim 69, wherein said amimoniumn sulphate granules have a Pfizer hardness of at least about 9.8 pounds. 71. The composition of matter as defined. by claim 70, wherein said ammonium sulphate granules have a Pfizer hardness of between about 9.8 and 12.7 pounds. 72. The composition of matter as defined by claim 69, wherein said ammnoniumn sulphate granules have a pH of less than about 73. The composition of matter as defined by claim 72, wherein said ammonium sulphate granules have a pH of between about 2.5 and 74. The composition of matter as defined by claim 73, wherein said ammonium sulphate granules have a pH of between about 2.5 and 2.9.

475. The composition of matter as defined by claim 74, wherein said ammonium sulphate granules have a pH of about 2.7. 76. The composition of matter as defined by claim 69, wherein said ammoniumn sulphate granules comprise a metal selected from the group consisting of aluminium and iron. 77. The composition of matter as defined by claim 76, wherein said metal is aluminium. 78. The composition of matter as defined by claim WO 89/04291 PCT/AU88/00422 77, wherein said ammonium sulphate granules have an aluminium. content of greater than about 0.05% by weight. 79. The composition of matter as defined by claim 78, wherein said ammonium sulphate granules have an aluminium content of between about 0.05% and 1.06% by weight. The composition of matter as defined by claim 79, wherein said amnmoniumn sulphate granules have an aluminium content of between about 0.15% and 1.06% by weight. 81. The composition of matter as defined by claim wherein said ammoniumn sulphate granules have an aluminium content of between about 0. 20% and 0.40% by weight. 82. The composition of matter as defined by claim 69, wherein more than about 85.7% of said amnmoniumn sulphate granules are equal to or larger than +10 Tyler mesh screen size. 83. The composition of matter as defined by claim 82, wherein more than about 95% of said -ranules are I equal to or larger than +10 Tyler mesh screen size. f 84. The composition of matter as def ined by claim 83, wherc.'in at least about 99% of said granules are equal to or larger than +10 Tyler mesh screen size. 85. A composition of matter comprising free- U flowing, non-caking ammonium sulphate granules wherein more than about 85.7% of said granules are equal to or Ularger than +10 Tyler mesh screen size. t 86. The comaposition of matter as defined by claim 85, wherein more than about 95% of said granules are equal to or larger than +10 Tyler mesh screen size. 87. The composition of matter as defined by claim 86, wherein at least about 99% of said granules are equal to or larger than +10 Tyler mesh screen size. 88. The composition of matter as defined by claim WO 89/04291 PCrr/AU88/00422 31 wherein said amnmoniumn sulphate granules have a pH of less than about 89. The composition of matter as defined by claim 88, wherein said ammoniumn sulphate granules have a pH of between about 2.5 and The composition of matter as defined by claim 89, wherein said ammonium sulphate granules have a pH of between about 2.5 and 2.9. 91. The composition of matter as defined by claim 90, wherein said ammonium sulphate granules have a pH of about 2.7. V92. The composition of matter as defined by claim wherein said ammonium sulphate granules have a Pfizer hardness of greater than about 6.8 pounds. 93. The composition of matter as defined by claim 92, wherein said ammonium sulphate granules have a Plizer hardness of at least about 9.8 pounds. 94. The composition of matter as defined by claim 93, wherein said ammoniumn sulphate granules have a Pfizer hardness of between about 9.8 and 12.7 pounds. The composition of matter as defined by claim wherein said ammonium sulphate granules comprise a metal selected f rom the group consisting of aluminium. and iron. 96. The composition of matter as def ined by claim wherein said metal is aluminium. 97. The composition of matter as defined by claim 96, wherein said ammnonium sulphate granules have an content of greater than about 0.05% by weight. 98.The composition of matter as defined by claim 97, wherein said amimonium sulphate granules have an aluminium content of between about 0.05% and 1.06% by weight. 99. The composition of matter as defined by claim 98, wherein -said ammonium sulphate granules have an WO 89/04291 PCT/AU88/00422 32 aluminium content of between about 0.15% and 1.06% by weight. 100. The composition of matter as defined by claim 99, wherein said ammonium sulphate granules have an aluminium content of between about 0.20% and 0.40% by weight. 101. A composition of matter comprising free- f lowing, non-caking ammonium sulphate granules wherein said ammonium sulphate granules have a pH of less than K 10 about 4.0; a Pfizer hardness of greater than about pounds; an aluminium content of more than about 0.05% by weight; and further wherein more than about 85.7% of said ammonium sulphate granules equal or exceed Tyler mesh screen size. 102. The composition of matter as defined by claim 101, wherein said ammonium sulphate granules have a pH of between about 2.5 and 4.0; have a Pfizer hardness of at least about 9.8 pounds; and have an aluminium content of between about 0.05% and 1.06% by weight; and further wherein more than about 95% of said ammonium sulphate granules equal or exceed +10 Tyler mesh screen size. 103. The composition of matter as defined by claim 102, wherein said ammonium sulphate granules have a pH of between about 2.5 and 2.9; have a Pfizer hardness of between about 9.8 and 12.7 pounds; and have an aluminium content of between about 0.20% and 0.40% by weight; and further wherein at least about 99% of said ammonium sulphate granules equal or exceed +10 Tyler mesh screen size. st BJ i INTERNATIONAL SEARCH REPORT Iternational Application No PCT/ AU 88/00422 1. CLASSIFICATION OF SUBJECT MATTER (if several ciassilicflon symbols apply, indicate all) According to internati~nai Patent Clasaicalion (IPC) or to both National Classification and IPC Int. Cl. C01C 1/242, COIC 1/24, B01J 2/30 It. FIELDS SEARCHED Minimum Documentation Searched Classification Syster, Ciasaification Symbol* IPC C01C 1/242, C01C 1/24, B01J 2/30 Documentation Searched other then Minimum Documentation to the Extent that such Documents ar* Included In the Fields Searched a AU IPC as above 1l1. DOCUMENTS CONSIDERIED TO of RELIVANTO Category a Citation of Document. 11 with Indication. where appropriate. of the relevant PaASSUGes Reievant to Claim No."1 X AU,B, 27818/30 (WI LLIAM GORDON ADAM)'10 April 1931 (1-20,40-42, (10.04.31) See column 5 lines 21-40, column 4 46-50,54-5717 lines 30-39, Claims 1,3 and 5 61-65) Y DE,C, 648539 FARBENINDUSTRIE AKT.-GES) August (1-23,40-42, 1937 (03.08.3-7) See page 2 lines 75-116, Claim 1 46-49,54-57, 61-65). Y DE,C, 651311 FARBENINDUSTRIE AKT.-GES) (1-23,40-42, 11 October 1937 (11.10.37) See page 1 lines 30-49, 46-49,54-57, Claim 1 61-65) A DE,C, 671784 (IMPERIAL CHEMICAL INDUSTRIES LIMITED) 14 February 1939 (14.02.39) See page 2 column 2 lines 75-116, Claim 1 A IDrE,C, 877297 (IMPERIAL CHEMICAL INDUSTRIES LIMITED) 1 21 May 1953 (21.05.53) See page 1 column 1 lines 4-10, page 2 colrimn 2 lines 108-121, page 3 column 3 lines 30-34, Claim 1 X US,A, 2782097 (JOHN J. COSTOLOW) 19 February 1957 (1-20,40-42, (19.02.57) See column 3 lines 50-52, Claim 3 46-50 54-57, (continued) 61-65, a Special categoutee of cited documents: 1e -r T lter document published aht the lntornational fiing date docuentdefi~ngthegeneal tat of he rt hichIs ot r priority date and not in conflict with 1he application but ocuentdofiingthegenral tat oftheart hic Isnot cited to und ,retand the principle or thocry underlying the csidered to be of particular relevanors Invention ,r Ne documvent butA pubiehed on or ehelr the International "X.document o particular relevance; the claimed Invention suem dale cannot be considered novel or cannot be considered to IV decumenti which may throw doubte on priority clalmn(s) Or Involve an inventive step which Is cited to establish the publication date of another document of particular relevance:' the cilimed Invention citail" or other speciall retasion (as specified) cannot be considered to Involve an inventive step when the 0" decent eferwlg te an oral disclosure, use. oxhibitlon or document is combined with one or more other such docu- ete means ments, such combination being obvious to a person skilled "110 decumet published pror to the International filing date but In the art. Waeir thtan the pority date claimed IV document member ot thoesame* patent family IV. CIERTIFICATION Cate elthe Actual Comoletion of the tnternotional Search Date of Mailing of this International Search Report 2 February 1989 (02.02.89) (O Z j ~6L9, tntemt- ee Searching Authority Signature of Authorized Omfcor Australian Patent Office 1 J WERNER form FCTOSA4O isecendl shoot) (January I east j InlefnalionaiI Application No. PCT/AU 88/00422 I. FURTHER INFORMATION CONTINUED FROM THE SECOND SHEET x I AU,B, 84667/75 (492758) (AUSTRALIAN FERTILIZERS LTD) 17 March 1977 (17.03.77) See page 5 lines 22-23, page 6 lines 1-8, Claim 11 US,A, 4589904 (CECIL P. HARRISON) 20 May 1986 (20.05.86) (1-2,5-13, 16-20,40, 46-50,54,55, 61-65) V.Q OBSERVATIONS -WHERE CERTAIN CLAIMS WERE FOUND UNSEARCHABLE'I This International search report has not been established In respect of certain claims under Article 17(2) for the following reasons: IQr Claim because they relate to subject matter not required to be searched by this Authority, namely: 2QClaim numnbers because they relate to parts of the International application that do not comply with the prescribed require. ments to such an extent that no meaningful Inti-rntionai search can be carried out. opecfltcasiiy; Clim numdeL...... because they are dependent clis and are rnot drafted in a c-dance with t" seco~nd and thid genterio5s Of PCT Rle 6.4(a). Ve.Q OSZERVATIONS WHERE UNITY OF INVENTION IS LACKING'8 This International Searching Authority found multiple Inventione In this internatlonaol application as follows: As all required additional search le@is were timely paid by the applicttnt this international search report covers all searchable claims at the International epplicaltin. As only same at the required additional search lees were timely paid by the applicant, this International search report covers only thate cilims of the International application far which lees were paid, specifically claims: &0F No fuqulved additional search fete were timely paid by the applicant. Consequently, this International search report I& restricted to the Invention first mentioned In the claime: Itlls covered by claim numbers: As @If searchable claims could be searched without effort justifyingaen additionel lee, the International Searching Authority did not invite payment at any additional teo. Remark on Protest Q The additional esech lees were accompenied by applicantes protest. [3 He Protest accompanied the payment at additionel search lees. -Form, PCTIISA#2I@ (supplemental ehoet (JanuaryI 1955) I' M I ANNEX TO THE INTERNATIONAL SEARCH REPORT ON INTERNATICNAL APPLICATION NO. PCT/AU 88/00422 This Annex lists the known publication level patent family nmbers relating to the patent documents cited in the above-mentioned international search report. The Australian Patent Office is in no way liable for these particulars which are merely given for the purpose of information. Patent Document Cited in Search Patent Family Members R port AU 84667/75 GB 151589 IN 143341 JP 51076199 MY 118/79 PH 14581 END OF ANNEX MR.