Process for producing crystalline ammonium orthophosphate

Abstract

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Description

[0001] “PROCESS FOR PRODUCING CRYSTALLINE AMMONIUM ORTHOPHOSPHATE”

[0002] FIELD OF THE INVENTION

[0003] The present invention is in the field of crystalline ammonium orthophosphate production, more specifically diammonium orthophosphate and / or monoammonium orthophosphate.

[0004] STATE OF THE ART

[0005] Diammonium phosphate and monoammonium phosphate are important phosphates that are often used as fertilizers, fire retards and food additives for example in yeast nutrition.

[0006] Some processes for producing crystalline ammonium phosphates are already known. The processes disclosed in the prior arts involve the reaction of phosphoric acid with ammonia either in gaseous form or in solution.

[0007] However, the processes disclosed the prior art often lack versatility as they do not enable easy recycling of various flows of matter.

[0008] There is thus a continuous need to improved processes for the production of crystalline ammonium phosphate.

[0009] INVENTION SUMMARY

[0010] The inventors have surprisingly found that the present invention solves the aforementioned issues.

[0011] The present invention concerns a process for producing a crystalline ammonium orthophosphate [hereafter, AP] composition, comprising at least the steps of:

[0012] (i). contacting at least one phosphoric acid composition and at least one ammoniacal source in at least one first vessel [hereafter, vessel (I)], thereby forming at least one mixture wherein said mixture has a N / P molar ratio comprised between 1.35 and 1.55 and a pH of at least 5.20 and at most 6.40, preferably at least 5.5 and at most 6.3, more preferably at least 5.7 and at most 6.2; wherein N is the mol % of nitrogen atoms and P is the mol.% of phosphorus atoms; and wherein said phosphoric acid composition comprises, based on the total weight of said phosphoric acid composition, at least 45 wt.% of phosphorus expressed as P2O5 equivalents;

[0013] (ii). transferring at least part of said mixture from said vessel (I) to at least one second vessel [hereafter, vessel (II)],

[0014] (iii). adjusting said N / P molar ratio of said mixture in said vessel (II) to either at least 1.70 and at most 2.30 or to at least 0.70 and at most 1.30 thereby forming at least one first slurry [hereafter, slurry] in said vessel (II); said slurry comprising a solid residue comprising AP and a liquid phase;

[0015] (iv). optionally transferring at least part of said slurry from said vessel (II) to at least one third vessel [hereafter, vessel (III)];

[0016] (v). separating at least part of said solid residue comprising AP from said liquid phase;

[0017] (vi). drying said solid residue thereby obtaining an AP composition.

[0018] The present invention also concerns a crystalline ammonium phosphate, preferably obtained or obtainable from the above process.

[0019] The present invention also concerns the use of at least one polyphosphate in a process for producing a crystalline ammonium orthophosphate.

[0020] The present invention also concerns the use of at least one polyphosphate in at least one AP composition for reducing the caking of said AP composition.

[0021] DETAILED DESCRIPTION

[0022] In the context of the present invention, the term “comprising” should not be interpreted as excluding features or elements other than those explicitly mentioned. It should be construed as specifying the presence of the features or elements indicated, but does not exclude the presence or addition of one or more other features or elements. Thus, the scope of the expression "a method comprising steps A and B" should not be limited to methods consisting only of steps A and B. Similarly, a composition comprising components A and B should not be limited to compositions consisting only of components A and B. Accordingly, the terms "comprising" and "including" encompass the terms more restrictive “consisting essentially of’ and “consisting of”.

[0023] In the context of the present invention, if an element or component is said to be selected from a list of recited elements or components, it should be understood that the element or component can also be any one of the individual recited elements or components in said list, or can also be selected from a group consisting of any two or more of the explicitly listed elements or components.

[0024] Unless stated otherwise, all the percentages and ppm concentrations are respectively percentages by weight (= wt.%) and ppm in weight (= ppm).

[0025] The use of roman numerals such as (i), (ii), (iii) for designating steps in a process does not necessarily impart an order to said steps, unless specified otherwise. Thus, for example, a step (iii) can be carried out before a step (ii). If one of the steps is optional that means that it can sometimes be omitted. For example, if step (iii) is optional, the skilled in the art understands that step (iv) can be carried out after step (ii).

[0026] The terms “one”, “a”, “an” encompass the term “at least one”, “at least a” and “at least an” respectively. Similarly, if the term “said” encompasses “said at least one”.

[0027] As explained above, the present invention concerns a process for producing crystalline ammonium orthophosphate [hereafter, AP],

[0028] Said process may be continuous.

[0029] Within the context of the present invention, the term “ammonium orthophosphate” also denoted AP, encompasses diammonium orthophosphate ((NH4)2HPO4, also called “DAP”) and monoammonium orthophosphate ((NH4)H2PO4, also called “MAP”). Thus, the process according to the present invention can be a process for producing crystalline diammonium orthophosphate or crystalline mono orthophosphate.

[0030] The term “crystalline” is given its normal meaning by the skilled person in the art. Generally speaking, “crystalline AP” is intended to denote AP such as DAP or MAP in a solid crystalline form. Thus, crystalline AP usually excludes aqueous solutions of AP or granulated AP. Granulated AP is usually produced in a granulator or ammoniator-granulator through, among other things, water evaporation. Processes for obtaining granulated AP do not comprise a solid / liquid separation. Thus, granulated AP obtained via water evaporation usually contains more impurities than AP that is obtained in a crystallization process.

[0031] Within the context of the present invention, an AP composition is intended to denote a composition comprising AP. Preferably, said AP composition comprises at least 50.0 wt.% of AP, more preferably at least 70.0 wt.% of AP, even more preferably at least 90.0 wt.% of AP, even more preferably at least 95.0 wt.% of AP, even more preferably at least 99.0 wt.% of AP, even more preferably at least 99.5 wt.%, even more preferably at least 99.9 wt.% based on the total weight of said AP composition.

[0032] Preferably, said AP composition comprises at most 100.0 wt.% of AP.

[0033] Usually crystalline AP, such as crystalline DAP or crystalline MAP contains low amount of insoluble matter. Preferably, said AP composition comprises at most 0.50 wt.%, at most 0.10 wt.%, at most 0.05 wt.% of insoluble matter.

[0034] Preferably said AP composition comprises, based on the total weight of said AP composition at most 150 ppm, at most 100 ppm, at most 75 ppm of iron. Preferably said AP composition comprises, based on the total weight of said AP composition at most 0.100 wt.%, preferably at most 0.075 wt.%, more preferably at most 0.050 wt.% of fluor.

[0035] Preferably said AP composition comprises, based on the total weight of said AP composition at most 1000 ppm, at most 750 ppm, at most 500 ppm of Al.

[0036] Preferably said AP composition comprises, based on the total weight of said AP composition at most 2.5 wt.%, preferably at most 2.0 wt.%, more preferably at most 1.5 wt.%, even more preferably at most 1.0 wt.% of sulfur atoms expressed as SO3 equivalents.

[0037] Preferably, said AP composition comprises, based on the total weight of said AP composition:

[0038] • at most 0.1 wt.% of insoluble matter; and

[0039] • at most 75 ppm of iron; and

[0040] • at most 0.050 wt.% of fluor; and

[0041] • at most 500 ppm of Al; and

[0042] • at most 1.0 wt.% of sulfur atoms expressed as SO3 equivalents.

[0043] Preferably, said AP composition comprises, based on the total weight of said AP composition:

[0044] • at least 90.0 wt.% of AP, even more preferably at least 95.0 wt.% of AP, even more preferably at least 99.0 wt.% of AP, even more preferably at least 99.5 wt.%, even more preferably at least 99.9 wt.% based on the total weight of said AP composition; and

[0045] • at least 52 wt.% and at most 65 wt.% of phosphorus expressed as P2O5 equivalents; and

[0046] • at most 0.1 wt.% of insoluble matter; and

[0047] • at most 75 ppm of iron; and

[0048] • at most 0.050 wt.% of fluor; and • at most 500 ppm of Al; and

[0049] • at most 1.0 wt.% of sulfur atoms expressed as SO3 equivalents; and

[0050] Preferably, said AP composition is a DAP composition comprising, based on the total weight of said DAP composition:

[0051] • at least 90.0 wt.%, even more preferably at least 95.0 wt.%, even more preferably at least 99.0 wt.%, even more preferably at least 99.5 wt.%, even more preferably at least 99.9 wt.% of DAP; and

[0052] • at least 52 wt.% and at most 56 wt.% of phosphorus expressed as P2O5 equivalents; and

[0053] • at most 0.01 wt.% of insoluble matter; and

[0054] • at most 75 ppm of iron; and

[0055] • at most 0.050 wt.% of fluor; and

[0056] • at most 500 ppm of Al; and

[0057] • at most 1.0 wt.% of sulfur atoms expressed as SO3 equivalents; and

[0058] • preferably at most 0.1 wt. % of water.

[0059] Preferably, said AP composition is a MAP composition comprising, based on the total weight of said MAP composition:

[0060] • at least 90.0 wt.%, even more preferably at least 95.0 wt.%, even more preferably at least 99.0 wt.%, even more preferably at least 99.5 wt.%, even more preferably at least 99.9 wt.% of MAP; and

[0061] • at least 55 wt.% and at most 65wt.% of phosphorus expressed as P2O5 equivalents; and

[0062] • at most 0.1 wt.% of insoluble matter; and

[0063] • at most 75 ppm of iron; and

[0064] • at most 0.050 wt.% of fluor; and

[0065] • at most 500 ppm of Al; and • at most 1.0 wt.% of sulfur atoms expressed as SO3 equivalents.

[0066] Preferably, said AP composition essentially consists of AP. The expression “essentially consisting of” is intended to denote that any additional ingredient in said AP composition, different from AP such as impurities, including for example water, insoluble salts, sulphates and / or fluorides are only present in a minor amount, typically, less than 3 wt.%, more advantageously less than 2 wt.%, even more advantageously less than 1 wt.%; being understood that said additional ingredients do not substantially modify the properties of said AP composition, i.e. do not materially affect the essential characteristics of said AP composition.

[0067] Step (i)

[0068] In step (i), at least one phosphoric acid composition is contacted with at least one ammoniacal source in at least one first vessel [hereafter, vessel

[0069] (I)], thereby forming at least one mixture wherein said mixture has a N / P molar ratio comprised between 1.35 and 1.55 a pH of at least 5.20 and at most 6.40, preferably at least 5.5 and at most 6.3, more preferably at least 5.7 and at most 6.2; wherein N is the mol % of nitrogen atoms and P is the mol.% of phosphorus atoms; and wherein said phosphoric acid composition comprises, based on the total weight of said phosphoric acid composition, at least 45 wt.% of phosphorus expressed as P2O5 equivalents.

[0070] Within the context of the present invention, the N / P molar ratio can be measured by any technique known by the skilled person in the art. If desired, the N / P molar ratio of the mixture can be measured with a titrator directly in the vessel (I) and / or (II) or from a sample of the vessel (I) and / or

[0071] (II).

[0072] The process according to the present invention, the N / P molar ratios can be measure through titration.

[0073] Within the context of the present invention, any type of vessel can be used as vessel (I), (II) and (III). Each of vessels (I), (II) and (III) can be the same types of vessels. Preferably, each vessel comprises homogenization means, such as agitation middles, agitators, baffles, ...

[0074] Within the context of the present invention, the term “phosphoric acid composition” is intended to denote a composition comprising phosphate ions, preferably phosphoric acid. Suitable examples include but are not limited to slurries comprising phosphate ions, preferably phosphoric acid, solutions comprising phosphate ions, preferably phosphoric acid.

[0075] Said phosphoric acid composition is preferably a liquid (a solution) or a suspension.

[0076] Said phosphoric acid composition preferably comprises, based on the total weight of said phosphoric acid composition, at least 45 wt.%, more preferably at least 50 wt.%, more preferably at least 58 wt.%, more preferably at least 60 wt.%, more preferably at least 62 wt.%, even more preferably at least 65 wt.% of phosphorus expressed as P2O5 equivalents. Said phosphoric acid composition preferably can comprise, based on the total weight of said phosphoric acid composition, at most 75 wt.%, preferably at most 70 wt.%, preferably at most 67 wt.%, preferably at most 65 wt.%, even more preferably at most 60 wt.% of phosphorus expressed as P2O5 equivalents.

[0077] In a preferred embodiment, said phosphoric acid composition preferably comprises, based on the total weight of said phosphoric acid composition, at least 45 wt.% and at most 75 wt.%, preferably at least 50 wt.% and at most 70 wt.%, even more preferably at least 58 wt.% and at most 65 wt.% of phosphorus expressed as P2O5 equivalents.

[0078] The term “ammoniacal source” is intended to denote any material comprising ammonium ions and / or ammonia and / or able to release ammonia or ammonium ions in solution.

[0079] Thus, said ammoniacal source can be gaseous ammonia or an ammonia solution. An ammonia solution is intended to denote a solution comprising ammonia and / or ammonium salts. Preferably, said ammoniacal source, in particular used in step (I), is gaseous ammonia or an ammonia solution, preferably said ammoniacal source is a gas of ammonia.

[0080] Preferably, said ammoniacal source, in particular used in step (I), comprises, based on the weight of said ammoniacal source at least 50 wt.%, preferably at least 80 wt.%, preferably at least 90 wt.%, preferably at least 95 wt.% of ammonia. Preferably said ammonia source, in particular used in step (I), comprises, based on the weight of said ammoniacal source at most 100 wt.%, of ammonia.

[0081] In a preferred embodiment, said ammoniacal source, in particular used in step (I), comprises, based on the weight of said ammonia source at least 50 wt.% and at most 100 wt.%, preferably at least 80 wt.% and at most 100 wt.%, more preferably at least 90 wt.% and at most 100 wt.%, even more preferably at least 95 wt.% and at most 100 wt.% of ammonia.

[0082] Preferably, said ammoniacal source is a gas comprising, based on the weight of said gas at least 75 wt.%, preferably at least 90 wt.%, preferably at least 95 wt.%, preferably at least 98 wt.% of ammonia. Preferably said ammoniacal source is a gas and comprises, based on the weight of said gas at most 100 wt.% of ammonia.

[0083] In a preferred embodiment, said ammoniacal source is a gas comprising, based on the weight of said gas at least 75 wt.% and at most 100 wt.%, preferably at least 95 wt.% and at most 100 wt.% of ammonia.

[0084] Preferably, said ammoniacal source is a gas that essentially consists of ammonia. The expression “essentially consisting of’ is intended to denote that any additional ingredient in said gas, different from ammonia such as impurities, including for example water, are only present in a minor being understood that said additional ingredients do not substantially modify the properties of said ammoniacal source, i.e., do not materially affect the essential characteristics of said gas. Preferably, the pH of said mixture is of at least 5.20, preferably at least 5.30, more preferably at least 5.40, even more preferably at least 5.50, even more preferably at least 5.60, even more preferably at least 5.70. Preferably, the pH of said mixture is of at most 6.50, preferably at most 6.40, more preferably at most 6.30, even more preferably at most 6.20.

[0085] In a preferred embodiment, the pH of said mixture is of at least 5.20 and at most 6.50, preferably at least 5.30 and at most 6.50, more preferably at least 5.40 and at most 6.40, even more preferably at least 5.50 and at most 6.30, even more preferably at least 5.60 and at most 6.20, even more preferably at least 5.70 and at most 6.20.

[0086] Preferably, said phosphoric acid composition comprises based on the total weight of said phosphoric acid composition at most 2000 ppm, preferably at most 1800 ppm, more preferably at most 1600 ppm, more preferably at most 1500 ppm of sulfur atoms expressed as SO3.

[0087] Said phosphoric acid composition can comprise based on the total weight of said phosphoric acid composition at least 100 ppm, or at least 500 ppm of sulfur atoms expressed as SO3.

[0088] In an embodiment, said phosphoric acid composition comprises based on the total weight of said phosphoric acid composition at least 100 and at most 2000 ppm, preferably at least 100 and at most 1800 ppm, more preferably at least 100 and at most 1500 ppm of sulfur atoms expressed as SO3.

[0089] Preferably, said phosphoric acid composition comprises based on the total weight of said phosphoric acid composition at most 700 ppm, preferably at most 650 ppm, more preferably at most 550 ppm, even more preferably at most 500 ppm, even more preferably at most 400 ppm, even more preferably at most 300 ppm, even more preferably at most 200 ppm, even more preferably at most 100 ppm, even more preferably at most 50 ppm of F. Said phosphoric acid composition can comprise based on the total weight of said phosphoric acid composition at least 1 ppm, or at least 2 ppm of F.

[0090] In an embodiment, said phosphoric acid composition comprises based on the total weight of said phosphoric acid composition at least 1 and at most 700 ppm, preferably at least 1 and at most 650 ppm, more preferably at least 1 and at most 550 ppm, even more preferably at least l and at most 500 ppm, even more preferably at least 1 and at most 400 ppm, even more preferably at least 1 and at most 300 ppm, even more preferably at least 1 and at most 200 ppm, even more preferably at least 1 and at most 100 ppm of F.

[0091] In a preferred embodiment, said phosphoric acid composition preferably comprises based on the total weight of said phosphoric acid composition:

[0092] . at least 100 and at most 2000 ppm, preferably at least 100 and at most 1800 ppm, more preferably at least 100 and at most 1500 ppm of sulfur atoms expressed as SO3;

[0093] • at least 1 and at most 300 ppm, even more preferably, preferably at least 1 and at most 200 ppm, even more preferably at least 1 and at most 100 ppm of F;

[0094] In a preferred embodiment, said phosphoric acid composition preferably comprises based on the total weight of said phosphoric acid composition:

[0095] • at least 51 wt.% and at most 58 wt.%, preferably at most 56 wt.% of phosphorus expressed as P2O5 equivalents;

[0096] . at least 100 and at most 1500 ppm of sulfur atoms expressed as SO3;

[0097] • at least 1 and at most 300 ppm, even more preferably, preferably at least 1 and at most 200 ppm, even more preferably at least 1 and at most 100 ppm of F; The advantage of the step (i) according to the present invention is that the N / P molar ratio in said vessel (I) is below the precipitation threshold. Thus, said mixture obtained in step (i) contains little or no solid AP. Thus, said vessel (I) and / or step (i) can be used to recycle other AP containing materials such as fines (see for example step (ix)) and dusts (for example obtained from step (viii)) which can come from other steps or part of said process. Other AP containing materials coming from other processes, or other steps of the process according to the present invention or AP containing materials that would have otherwise been discarded or rejected from the process according to the present invention or other processes, can also be recycled by addition thereof in said vessel (I) and / or step (i).

[0098] Said process preferably comprises a step (vii) of adding at least part of said liquid phase obtained in step (v) into said vessel (I) and / or said vessel (II) and / or optionally said vessel (III). Thus, enabling recycling at least part of said liquid phase.

[0099] Preferably, at least 10 wt.%, more preferably at least 20 wt.%, even more preferably at least 30 wt.%, even more preferably at least 50 wt.%, even more preferably at least 75 wt.% of said liquid phase is added into said vessel (I) and / or said vessel (II) and / or optionally said vessel (III). Preferably, at most 100 wt.%, more preferably at most 90 wt.%, more preferably at most 80 wt.%, even more preferably at most 75 wt.% of said liquid phase is added into said vessel (I) and / or said vessel (II) and / or optionally said vessel (III).

[0100] In a preferred embodiment, at least 10 wt.% and at most 100 wt.%, more preferably at least 20 wt.% and at most 90 wt.%, even more preferably at least 30 wt.% and at most 80 wt.%, even more preferably at least 30 wt.% and at most 75 wt.% of said liquid phase is added into said vessel (I) and / or said vessel (II) and / or optionally said vessel (III). Said process can also comprise a step of adding crystalline AP into said vessel (I).

[0101] Preferably, said process can comprise a step of adding at least 0.5 wt.%, preferably at least 1 wt.%, more preferably at least 5 wt. % of crystalline AP into said step (i) and / or into said vessel (I), with regards to the total of crystalline AP produced in said process according to the present invention. Preferably, said process can comprise a step of adding at most 30 wt.%, preferably at most 28 wt.%, more preferably at most 25 wt. % of crystalline AP into said vessel (I), with regards to the total of crystalline AP produced in said process according to the present invention.

[0102] It was observed that the addition of ammonium phosphate into said step (i) and / or into said vessel (I) improves the yield of the overall process according to the present invention.

[0103] Preferably, said step (i) of contacting at least one phosphoric acid composition and at least one ammoniacal source is carried out at a temperature of at least 40 °C and preferably at most 100°C, more preferably at least 50 °C and preferably at most 100 °C.

[0104] Preferably, if said process is a process for preparation diammonium orthophosphate, said step (i) of contacting at least one phosphoric acid composition and at least one ammoniacal source is carried out at a temperature of at least 40 °C, more preferably at least 50 °C, more preferably at least 55°C. Preferably, if said process is a process for preparation diammonium orthophosphate, said step (i) of contacting at least one phosphoric acid composition and at least one ammoniacal source is carried out at a temperature of at most 80 °C, more preferably at most 70°C, even more preferably at most 65 °C.

[0105] In a preferred embodiment, if said process is a process for preparation diammonium orthophosphate, said step (i) of contacting at least one phosphoric acid composition and at least one ammoniacal source is carried out at a temperature of at least 40 °C and at most 80°C, more preferably at least 50 °C and at most 70 °C, more preferably at least 55°C and at most 65°C.

[0106] Preferably, if said process is a process for preparation monoammonium orthophosphate, said step (i) of contacting at least one phosphoric acid composition and at least one ammoniacal source is carried out at a temperature of at least 80 °C, more preferably at least 85 °C, even more preferably at least 90°C.

[0107] Preferably, if said process is a process for preparation monoammonium orthophosphate, said step (i) of contacting at least one phosphoric acid composition and at least one ammoniacal source is carried out at a temperature of at most 110 °C, even more preferably at most 100°C.

[0108] Preferably, if said process is a process for preparation monoammonium orthophosphate, said step (i) of contacting at least one phosphoric acid composition and at least one ammoniacal source is carried out at a temperature of at least 80 °C and at most 110 °C, more preferably at least 85 °C and at most 110°C, even more preferably at least 90°C and at most 110°C, even more preferably at least 90°C and at most 100°C.

[0109] Step (ii) - Step (iii) - Step (iv)

[0110] Then, in step (ii), at least part of said mixture is transferred from said vessel (I) to at least one second vessel [hereafter, vessel (II)].

[0111] Thereafter, the N / P molar ratio of said mixture in said vessel (II) is adjusted to either:

[0112] • at least 1 .70 and at most 2.30, or to

[0113] • at least 0.70 and at most 1.30 thereby forming at least one first slurry [hereafter, slurry] in said vessel (II).

[0114] Preferably, the N / P molar ratio in said vessel (II) is adjusted to at least 1.70 and at most 2.30, preferably at least 1.80 and at most 2.10, when said process is a process for producing crystalline diammonium orthophosphate.

[0115] Preferably, the N / P molar ratio in said vessel (II) is adjusted to at least 0.70 and at most 1.30, preferably at least 0.90 and at most 1.20, when said process is a process for producing crystalline monoammonium orthophosphate.

[0116] Optionally, said process can comprise at least one step of concentrating said slurry. Said concentration can be achieved by heating, or heating under vacuum or partial vacuum.

[0117] The slurry formed in step (iii) comprises AP, and a liquid phase.

[0118] Preferably, the slurry comprises at least 500 g, preferably at least 600 g, more preferably at least 700 g, even more preferably at least 800 g of AP per liter of slurry.

[0119] Preferably, said slurry comprises at most 1500 g, more preferably at most 1300 g, even more preferably at most 1200 g, even more preferably at most 1100 g, even more preferably at most 1000 g of AP per liter of slurry.

[0120] In a preferred embodiment, slurry comprises at least 500 g and at most 1500 g, preferably at least 600 g and at most 1300 g, more preferably at least 700 g and at most 1200 g, even more preferably at least 800 g and at most 1100 g of AP per liter of slurry.

[0121] Said N / P ratio can be adjusted by any means known by the skilled person in the art. Examples of means for adjusting said N / P ratio include but are not limited to: addition of at least one ammoniacal source, addition of at least one phosphoric acid composition.

[0122] Preferably, said the N / P molar ratio of said mixture in said vessel (II) is adjusted by addition in said vessel (II) of at least one ammoniacal source and / or at least one phosphoric acid composition as defined above. Preferably, when said process according to the present invention is a process for producing a crystalline DAP, said ammoniacal source is added.

[0123] Preferably, when said process according to the present invention is a process for producing a crystalline MAP, said phosphoric acid composition is added.

[0124] Preferably, said ammoniacal source added in said vessel (II) is gaseous ammonia or an ammonia solution, preferably said ammoniacal source is a gas of ammonia.

[0125] Preferably, said ammoniacal source, in particular used in step (II), is gaseous ammonia or an ammonia solution (such as ammonium salts), preferably said ammoniacal source is a gas of ammonia.

[0126] Preferably, said ammoniacal source, in particular used in step (II), comprises, based on the weight of said ammoniacal source at least 50 wt.%, preferably at least 80 wt.%, preferably at least 90 wt.%, preferably at least 95 wt.% of ammonia. Preferably said ammonia source, in particular used in step (II), comprises, based on the weight of said ammoniacal source at most 100 wt.%, of ammonia.

[0127] In a preferred embodiment, said ammoniacal source, in particular used in step (II), comprises, based on the weight of said ammonia source at least 50 wt.% and at most 100 wt.%, preferably at least 80 wt.%, more preferably at least 90 wt.%, even more preferably at least 95 wt.% and at most 100 wt.% of ammonia.

[0128] Preferably, said ammoniacal source is a gas comprising, based on the weight of said ammoniacal gas at least 75 wt.%, preferably at least 90 wt.%, preferably at least 95 wt.%, preferably at least 98 wt.% of ammonia. Preferably said ammoniacal source is an ammoniacal gas and comprises, based on the weight of said ammoniacal gas at most 100 wt.% of ammonia.

[0129] In a preferred embodiment, said ammoniacal source is a gas comprising, based on the weight of said ammonia gas at least 75 wt.% and at most 100 wt.%, preferably at least 95 wt.% and at most 100 wt.% of ammonia.

[0130] Preferably, said ammoniacal source is a gas that essentially consists of ammonia. The expression “essentially consisting of’ is intended to denote that any additional ingredient in said ammoniacal source, different from ammonia such as impurities, including for example water, are only present in a minor being understood that said additional ingredients do not substantially modify the properties of said ammoniacal source, i.e. , do not materially affect the essential characteristics of said ammoniacal source.

[0131] Said phosphoric acid composition is preferably a liquid (a solution) or a suspension.

[0132] Said phosphoric acid composition preferably comprises, based on the total weight of said phosphoric acid composition, at least 45 wt.%, more preferably at least 50 wt.%, more preferably at least 58 wt.%, more preferably at least 60 wt.%, more preferably at least 62 wt.%, even more preferably at least 65 wt.% of phosphorus expressed as P2O5 equivalents. Said phosphoric acid composition preferably can comprise, based on the total weight of said phosphoric acid composition, at most 75 wt.%, preferably at most 70 wt.%, preferably at most 67 wt.%, preferably at most 65 wt.%, even more preferably at most 60 wt.% of phosphorus expressed as P2O5 equivalents.

[0133] In a preferred embodiment, said phosphoric acid composition preferably comprises, based on the total weight of said phosphoric acid composition, at least 45 wt.% and at most 75 wt.%, preferably at least 50 wt.% and at most 70 wt.%, even more preferably at least 58 wt.% and at most 65 wt.% of phosphorus expressed as P2O5 equivalents.

[0134] Optionally at least part of said slurry is transferred from said vessel

[0135] (II) to at least one third vessel [hereafter, vessel (III)]. The vessel (III) is thus essentially used for maturation of the crystalline AP in said slurry, when necessary.

[0136] The mixture can be transferred from said vessel (I) to said vessel (II) in step (II) and optionally said slurry can be transferred from said vessel (II) to said vessel (III) in step (iv) via techniques such as overflow, pumping system, valves, aspiration, gravity,

[0137] Preferably, the mixture can be transferred from said vessel (I) to said vessel (II) in step (II) via overflow. The slurry can be optionally transferred from said vessel (II) to said vessel (III) in step (iv) via overflow.

[0138] Preferably, the total residence time in said vessel (I), and said vessel (II) and optionally said vessel (III) is of at least 10 hours, preferably at least 11 hours, more preferably at least 12 hours. Preferably, the total residence time in said vessel (I), and said vessel (II) and optionally said vessel (III) is of at most 24 hours, preferably at most 23 hours, more preferably at most 22 hours, even more preferably at most 21 hours.

[0139] In a preferred embodiment, the total residence time in said vessel (I), and said vessel (II) and optionally said vessel (III) is of at least 10 hours and at most 24 hours, preferably at least 11 hours and most 23 hours, more preferably at least 12 hours and at most 22 hours, even more preferably at least 12 hours and at most 21 hours.

[0140] Within the context of the present invention, the residence time is given its normal meaning in the field. The residence time can be defined as the mean volume of the vessels (I) and (II) and optionally (III) divided by total input streams of ammoniacal source, of phosphoric acid composition and optionally water.

[0141] Preferably, the temperature of said slurry in said vessel (II) is of at least 40 °C, preferably at least 45 °C, more preferably at least 50°C. Preferably, the temperature of said slurry in said vessel (II) is of at most 130 °C, preferably at most 120°C, more preferably at most 100 °C. In a preferred embodiment, the temperature of said slurry in said vessel (II) is of at least 40°C and at most 130°C, preferably at least 45°c and at most 120°C, more preferably at least 50 °C and at most 100°C.

[0142] Preferably, the temperature of said slurry in said vessel (III) is of at least 40 °C, preferably at least 45 °C, more preferably at least 50°C. Preferably, the temperature of said slurry in said vessel (III) is of at most 130 °C, preferably at most 120°C, more preferably at most 100 °C. In a preferred embodiment, the temperature of said slurry in said vessel (III) is of at least 40°C and at most 130°C, preferably at least 45°c and at most 120°C, more preferably at least 50 °C and at most 100°C.

[0143] Step (v)

[0144] In step (v), at least a part of said solid residue comprising AP is separated from said liquid phase.

[0145] The separation can be achieved by any suitable means known by the skilled person in the art such as for example filtration or decantation or sedimentation or centrifugation. Preferably, the filtration is done with a device such as a band filter, drum filter, press filter, basket filter, centrifuge.

[0146] In particular, said liquid phase separated in step (v) can be for example a filtrate.

[0147] Preferably, said solid residue comprises at least 45 wt.%, more preferably at least 50 wt.%, even more preferably at least 55 wt. %, even more preferably at least 70 wt.%, even more preferably at least 80 wt.%, even more preferably at least 90 wt.% of AP, based on the total weight of said solid residue. Preferably, said solid residue comprises at most 10Ot.%, preferably at most 99 wt.%, more preferably at most 98 wt.%, even more preferably at most 95 wt.% of AP, based on the total weight of said solid residue.

[0148] In a preferred embodiment, said solid residue comprises at least 45 wt.% and at most 99 wt.%, more preferably at least 70 wt.% and at most 98 wt.%, even more preferably at least 80 wt.% and at most 98 wt.%, even more preferably at least 90 wt. / % and at most 95 w.% of AP, based on the total weight of said solid residue.

[0149] Preferably, said solid residue comprises at least 1 wt.%, more preferably at least 3 wt.%, even more preferably at least 5 wt.% of water, based on the total weight of said solid residue. Preferably, said solid residue comprises at most 30 wt.%, more preferably at most 20 wt.%, even more preferably at most 10 wt.% of water, based on the total weight of said solid residue.

[0150] In a preferred embodiment, said solid residue comprises at least 1 wt.% and at most 30 wt.%, more preferably at least 3 wt.% and at most 20 wt.%, even more preferably at least 5 wt.% and at most 10 wt.% of water, based on the total weight of said solid residue.

[0151] In a preferred embodiment, said solid residue comprises based on the total weight of said solid residue:

[0152] • at least 5 wt.% and at most 10 wt.% of water; and

[0153] • at least 90 wt.% and at most 95 wt.% of AP.

[0154] Step (vi)

[0155] In step (vi), said solid residue is dried, thereby providing an AP composition.

[0156] Within the context of the present invention, the term “drying” or “dried” is intended to refer to process by which the water content of what is being subjected to drying, is reduced (i.e., lower than before the action of drying). In other words, the AP composition obtained in step (vi) preferably comprises AP and a water content lower than the water content of said solid residue obtained in step (v).

[0157] Preferably, said AP composition comprises at least 50 wt.% of AP, more preferably at least 70 wt.% of AP, even more preferably at least 90 wt.% of AP, even more preferably at least 95 wt.% of AP, even more preferably at least 99 wt.% of AP, based on the total weight of said AP composition.

[0158] Preferably, said AP composition comprises at most 100 wt.% of AP.

[0159] Preferably, said AP composition essentially consists of AP. The expression “essentially consisting of’ is intended to denote that any additional ingredient in said AP composition, different from AP such as impurities, including for example water, insoluble salts, sulphates and / or fluorides are only present in a minor amount, typically, less than 3 wt.%, more advantageously less than 2 wt.%, even more advantageously less than 1 wt.%; being understood that said additional ingredients do not substantially modify the properties of said AP composition, i.e. do not materially affect the essential characteristics of said AP composition.

[0160] Preferably, said AP composition contains less than 1 ,5 wt.%, preferably less than 1 wt.%, preferably less than 0,5 wt.% water.

[0161] Preferably, said AP composition comprises at least 45 wt.%, preferably at least 50 wt.%, more preferably at least 51 wt.%, even more preferably at least 52 wt.%, even more preferably at least 53 wt.% of phosphorus expressed as P2O5 equivalents. Preferably, said AP composition comprises at most 65 wt.%, preferably at most 58 wt.%, more preferably at most 57 wt.%, even more preferably at most 56 wt.%, even more preferably at least 55 wt.% of phosphorus expressed as P2O5 equivalents.

[0162] In a preferred embodiment, said AP composition comprises at least 45 wt.% and at most 60 wt.%, preferably at least 50 wt.% and at most 58 wt.%, more preferably at least 51 wt.% and at most 57 wt.%, even more preferably at least 52 wt.% and at most 56 wt.%, even more preferably at least 53 wt.% and at least 55 wt.% of phosphorus expressed as P2O5 equivalents. Preferably, when 1 wt.% of said AP composition is dissolved in water, the resulting solution has a pH comprised between 3 and 10, preferably between 4 and 9. Preferably, when said AP composition is essentially made of MAP, when 1 wt.% of said AP composition is dissolved in water, the resulting solution has a pH comprised between 4 and 5.5.

[0163] Preferably, said AP composition comprises, based on the total weight of said AP composition, at least 55 wt.%, more preferably at least 58 wt.%, even more preferably at least 60 wt.% of phosphorus expressed as P2O5 equivalents. Preferably, said AP composition comprises based on the total weight of said AP composition, at most 65 wt.%, more preferably at most 63 wt.%, even more preferably at most 62 wt.% of phosphorus expressed as P2O5 equivalents.

[0164] In a preferred embodiment, said AP composition comprises based on the total weight of said AP composition, at least 55 wt.% and at most 65 wt.%, more preferably at least 58 wt.% and at most 63 wt.%, even more preferably at least 60 wt.% and at most 62 wt.% of phosphorus expressed as P2O5 equivalents.

[0165] Preferably, said AP composition comprises based on the total weight of said AP composition, at least 45 wt.%, more preferably at least 50 wt.%, even more preferably at least 52 wt.% of phosphorus expressed as P2O5 equivalents. Preferably, when said AP composition comprises based on the total weight of said AP composition, at most 60 wt.%, more preferably at most 58 wt.%, even more preferably at most 56 wt.% of phosphorus expressed as P2O5 equivalents.

[0166] In a preferred embodiment, when said AP composition comprises based on the total weight of said AP composition, at least 45 wt.% and at most 60 wt.%, more preferably at least 50 wt.% and at most 58 wt.%, even more preferably at least 52 wt.% and at most 56 wt.% of phosphorus expressed as P2O5 equivalents.

[0167] Preferably, when said AP composition is essentially made of DAP, when 1 g of said AP composition is dissolved in 100 g of water, the resulting solution has a pH comprised between 7.5 and 9, preferably between 7.5 and 8.5, more preferably between 7.5 and 8.1 . Preferably, when said AP composition is essentially made of MAP, when 1 g of said AP composition is dissolved in 100 g of water, the resulting solution has a pH comprised between 4.5 and 6; preferably between 4.7 and 5.5.

[0168] The drying step (vi) may be performed by any suitable means known by the skilled in the art. Preferably, said drying step (vi) may comprise drying said solid residue using a direct or indirect contact with a fluid (preferably hot fluid, preferably hot gases). The drying step (vi) may be carried out with a drying device such as (but not limited to) a fluidized bed, an atomizer, a flash dryer, a drum dryer, a spray dryer, or by a combination thereof.

[0169] Preferably said drying step (vi) is carried out until said AP composition obtained in step (vi) comprises at most 10 wt.%, preferably at most 5 wt.%, more preferably at most 2 wt.%, even more preferably at most 1 wt.% of water, based on the total weight of said AP composition.

[0170] Said solid residue is preferably dried in step (vi) for an overall time of at least 2 hours, more preferably at least 3 hours, even more preferably at least 4 hours. Said solid residue is preferably dried in step (vi) for at most 8 hours, more preferably at most 7 hours, even more preferably at most 6 hours. Alternatively, said solid residue may be dried in step (vi) substantially instantaneously, preferably for at least 15 seconds, more preferably at least 1 minute, even more preferably at least 3 minutes, even more preferably at least 5 minutes, even more preferably at least 10 minutes, even more preferably at least 15 minutes, even more preferably at least 30 minutes, even more preferably at least 1 hour. Said solid residue may be dried in step (vi) for at most 2 hours, more preferably at most 1 hour, even more preferably at most 45 minutes, even more preferably at most 20 minutes, even more preferably at most 10 minutes, even more preferably at most 5 minutes, even more preferably at most 1 minute. In a preferred embodiment, said solid residue may be dried in step (vi) during at least 10 seconds and at most 15 seconds, or at least 45 seconds and at most 90 seconds, or at least 4 minutes and at most 6 minutes or at least 10 minutes and at most 20 minutes, or at least 20 minutes and at most 40 minutes, or at least 1 hour and at most 2 hours.

[0171] Said steps (v) and (vi) can be carried out simultaneously (at the same time) or not or at least partially simultaneously.

[0172] Preferably, said drying step is a flash drying step.

[0173] Preferably, said drying step, more preferably flash drying step comprises:

[0174] • at least a step (vi a) of providing at least one stream of gas, preferably at a temperature of at least 80 °C, more preferably at last 90°C, more preferably at least 100°C, even more preferably at least 110°C; and

[0175] • at least a step (vi b) of contacting said solid residue with said at least one stream of gas, preferably during at least 1 second, more preferably at least 5 seconds, even more preferably at least 10 seconds, even more preferably at least 30 seconds, even more preferably least 1 minute, even more preferably at least 5 minutes, even more preferably at least 10 minutes, even more preferably at least 30 minutes, even more preferably at least 1 hour, even more preferably at least 2 hours.

[0176] Preferably, in said step (vi a), the at least one stream of gas is provided at a temperature of at most 200 °C, more preferably at most 180, even more preferably at most 160 °C, even more preferably at most 150 °C, more preferably at most 140°C, even more preferably at most 130 °C, even more preferably at most 120 °C.

[0177] In a preferred embodiment, said in said step (vi a), the at least one stream of gas is provided at a temperature of at least 90°C and at most 200 °C, more preferably at least 100°C and at most 180 °C, more preferably at least 110°C and at most 160°C, even more preferably at least 110°C and at most 150 °C, even more preferably at least 110°C and at most 130 °C.

[0178] Preferably, in said step (vi b), said solid residue is contacted with said at least one stream of gas during at most 10 hours, preferably at most 5 hours, even more preferably at most 2 hours, even more preferably at most 1 hour, even more preferably at most 30 minutes, even more preferably at most 10 minutes, even more preferably at most 5 minutes, even more preferably at most 1 minutes.

[0179] In a preferred embodiment, in said step (vi b), said solid residue is contacted with said at least one stream of gas during at least 1 second and at most 10 hours, preferably at least preferably during at least 1 minute and at most 5 hours, more preferably at least 5 minutes and at most 2 hours, even more preferably at least 10 seconds and at most 30 minutes.

[0180] Said step (vi a) and (vi b) can be carried out simultaneously or not or at least partially simultaneously.

[0181] Preferably, said AP composition comprises at most 2 wt.%, preferably at most 1 wt.%, more preferably at most 0.5 wt.%, even more preferably at most 0.1 wt. of water, based on the total weight of said AP composition.

[0182] Within the context of the present invention, water contents can be measured by thermogravimetric methods. Preferably, if the content of water is measured in an AP composition comprising DAP, the measurement can be done by weighting the AP composition before and after heating said AP composition at 45°C, the wt.% of water can then be deduced from the weight difference.

[0183] Preferably, if the content of water is measured in an AP composition comprising MAP and no DAP, the measurement can be done by weighting the AP composition before and after heating said AP composition at 105°C, the wt.% of water can then be deduced from the weight difference. In a preferred embodiment, said AP composition comprises based on the total weight of said AP composition:

[0184] • at most 0.5, preferably at most 0.1 wt.% of water; and

[0185] • at least 95.0 wt.% and at most 100 wt.%, more preferably at least 96.0 wt.% and at most 100 wt.%, even more preferably at least 97.0 wt.% and at most 100 wt.% of AP.

[0186] The gas coming from the drying step (vi) can be loaded with dusts. Thus, said drying step (vi) preferably further provides a gas comprising dusts. Said dusts comprise for example particles of AP such as DAP and / or MAP. Preferably, said dusts have a granulometry wherein at least 90 wt.% of said dust particles can pass through a mesh sieve of 500 pm or 400 pm, or 300 pm, or 200 pm.

[0187] Preferably, the drying step (vi) provides at least a gas comprising dusts comprising dust particles, preferably of AP such as DAP and / or MAP, wherein said dusts have a granulometry wherein at least 90 wt.% of said dust particles can pass through a mesh sieve of 500 pm or 400 pm, or 300 pm, or 200 pm

[0188] It is usually necessary to remove the dust from the stream of gas, before releasing the gas used during the drying step in the atmosphere.

[0189] Step (viii)

[0190] Optionally, after the drying step (vi), the gas used in the drying step (vi) contains dust of AP composition and needs to be cleaned.

[0191] Thus, the process according to the present invention can comprise a gas / solid separation step (viii) wherein at least part of said dusts contained in said gas used in said drying step, are removed from said gas, thereby providing:

[0192] • a treated gas, and

[0193] • dusts separated from said treated gas. The gas / solid separation step can be carried out by any means known by the skilled person in the art. Preferably, said gas / solid separation step can be carried out in device such as cyclonic separators, electrostatic precipitators, bag filters, sedimentation chamber, centrifuge separators and combination thereof.

[0194] At least part or all of said dusts separated from said treated gas, can be added in said vessel (I). Thus, said vessel (I) enables the recycling of the dusts separated from said treated gas, preferably from a gas / solid separation, in particular as defined above.

[0195] Preferably, said dusts separated from said treated gas comprise at least 95.0 wt.% and at most 100 wt.%, more preferably at least 96.0 wt.% and at most 100 wt.%, even more preferably at least 97.0 wt.% and at most 100 wt.% of AP. The AP can be MAP and / or DAP.

[0196] Preferably said gas used above in steps (viii) and / or (vi) can be air or dried air.

[0197] Step fix)

[0198] The process according to the present invention can comprise a step (ix) of washing said treated gas provided in step (viii) and / or exhaust gas coming from the different part of the process (e.g. vessel (I) and / or vessel (II) and / or step (x)) with water (such as for example demineralized water) or an aqueous solution, or an aqueous solution comprising phosphoric acid or a phosphoric acid composition, thereby preferably forming another composition comprising phosphoric acid (can also be called a composition comprising phosphoric acid (II)).

[0199] Said other composition comprising phosphoric acid or said composition comprising phosphoric acid (II), can be added to said vessel (I) and / or in step (i).

[0200] Said other composition comprising phosphoric acid or said composition comprising phosphoric acid (II) can be said phosphoric acid composition used in step (i). Said phosphoric acid composition, preferably phosphoric acid solution used in step (ix) preferably comprises at least 30 wt.%, more preferably at least 40 wt.%, even more preferably at least 50 wt.% of phosphoric acid, based on the total weight of said phosphoric acid composition or solution.

[0201] Said phosphoric acid composition, preferably phosphoric acid solution used in step (ix) preferably comprises at most 62 wt.%, more preferably at most 58 wt.%, even more preferably at most 56 wt.% of phosphoric acid, based on the total weight of said phosphoric acid composition or solution.

[0202] Said phosphoric acid composition, preferably phosphoric acid solution used in step (ix) preferably comprises at least 30 wt.% and at most 62 wt.%, more preferably at least 40 wt.% and at most 60 wt.%, even more preferably at least 50 wt.% and at most 58 wt.% of phosphoric acid, based on the total weight of said phosphoric acid composition or solution.

[0203] The resulting composition can be added in said vessel (I) and / or (II).

[0204] The resulting composition can form the phosphoric acid composition of step (i).

[0205] Step (x)

[0206] Preferably, said process can comprise at least one step (x) of separating at least one first fraction of said AP composition and optionally at least one second fraction of said AP composition, wherein said at least one second fraction has an average particle size, preferably a D50, higher than the average particle size, preferably a D50 of said AP composition and said at least one first fraction of AP has an average particle size, preferably a D50 lower than the average particle size, preferably the D50 of said AP composition, thereby adjusting the granulometric distribution of said AP composition.

[0207] Preferably, said AP composition, preferably obtained in step (x) has a D50 of at least 500 pm, preferably at least 550 pm, more preferably at least 600 pm, even more preferably at least 650 pm, even more preferably at least 700 pm. Preferably, said AP composition, preferably obtained in step (x) has a D50 of at most 1000 pm, preferably at most 950 pm, more preferably at most 900 pm, even more preferably at most 850 pm, even more preferably at most 800 pm.

[0208] In a preferred embodiment, said AP composition, preferably obtained in step (x) has a D50 of at least 500 pm and at most 1000 pm, preferably at least 550 pm and at most 950 pm, more preferably at least 600 pm and at most 900 pm, even more preferably at least 650 pm and at most 850 pm, even more preferably at least 700 pm and at most 800 pm.

[0209] The granulometric distribution can also be called the particle size distribution and is intended to denote the distribution of the different particles sizes of said AP composition.

[0210] Said step (x) can be achieved via any suitable techniques known by the skilled person in the art. Examples of such techniques include but are not limited to: sieving, centrifugating, sifting, screening and combinations thereof.

[0211] Preferably, the granulometric distribution of said AP composition is adjusted in step (x) so that at least 85.0 wt.%, preferably at least 90.0 wt.%, even more preferably at least 95.0 wt.%, even more preferably at least 97.0 wt.%, even more preferably at least 98.0 wt.%, even more preferably at least 99.0 wt.% of said AP composition obtained in step (x) can pass through a first sieve (I).

[0212] Preferably, said sieve (I) has a mesh of at least 1.5 mm, more preferably at least 1.7 mm, even more preferably at least 2.0 mm, even more preferably at least 2.4 mm. Preferably, said sieve (I) has a mesh of at most 3.5 mm, more preferably at most 3.0 mm, even more preferably at most 2.8 mm, even more preferably at most 2.7 mm.

[0213] In a preferred embodiment, said sieve (I) has a mesh of at least 1.5 mm and at most 3.5 mm, more preferably at least 1.7 mm and at most 3.0 mm, even more preferably at least 2.0 mm and at most 2.8 mm, even more preferably at least 2.4 mm and at most 2.7 mm.

[0214] In a most preferred embodiment, the granulometric distribution of said AP composition is adjusted so that at least 85.0 wt.%, preferably at least 90.0 wt.%, even more preferably at least 95.0 wt.%, even more preferably at least 97.0 wt.%, even more preferably at least 98.0 wt.%, even more preferably at least 99.0 wt.% of said AP composition obtained in step (x) can pass through a first sieve (I) having a mesh of 2.5 mm.

[0215] Preferably, at least 85.0 wt.%, preferably at least 90.0 wt.%, more preferably at least 94.0 wt.%, even more preferably at least 95.0 wt.%, even more preferably at least 96.0 wt.% of said AP composition obtained in step (x) can pass through a second sieve (II).

[0216] Preferably, said at least sieve (II) has a mesh of at least 0.1 mm, even preferably at least 0.5 mm, even more preferably at least 1 mm, even more preferably at least 1.2 mm, more preferably at least 1.3 mm, even more preferably at least 1.4 mm. Preferably, said at least sieve (II) has a mesh of at most 2.5 mm, more preferably at most 2.0 mm, even more preferably at most 1 .7 mm, even more preferably at most 1 .6 mm.

[0217] Preferably, said sieve (II) has a mesh of at least 0.1 mm and at most 2.5 mm, more preferably at least 0.5 mm and at most 2.0 mm, even more preferably at least 1.2 mm and at most 1.7 mm, even more preferably at least 1 .3 mm and at most 1 .6 mm.

[0218] In a most preferred embodiment, the granulometric distribution of said AP composition is adjusted so that: at least 85.0 wt.%, preferably at least 90.0 wt.%, even more preferably at least 95.0 wt.%, even more preferably at least 97 wt.%, even more preferably at least 98 wt.%, even more preferably at least 99 wt.% of said AP composition obtained in step (x) can pass through a first sieve (I) having a mesh of 2.5 mm, and at least 85.0 wt.%, preferably at least 90.0 wt.%, even more preferably at least 94.0 wt.%, of said AP composition obtained in step (x) can pass through a second sieve (II) having a mesh of 1 .4 mm.

[0219] In another most preferred embodiment, the granulometric distribution of said AP composition is adjusted so that:

[0220] • at least 99.0 wt.% of said AP composition obtained in step (x) can pass through a first sieve (I) having a mesh of 2.5 mm and

[0221] • at least 94.0 wt.% of said AP composition obtained in step (x) can pass through a second sieve (II) having a mesh of 1.4 mm.

[0222] Preferably, at most 20 wt.%, more preferably at most 15 wt.%, even more preferably at most 10 wt.%, even more preferably at most 6 wt.%, even more preferably at most 5 wt.% of said AP composition obtained in step (x) can pass through a third sieve (III).

[0223] Preferably, said sieve (III) has a mesh of at least 50 pm, preferably at least 75 pm, preferably at least 100 pm, more preferably at least 125 pm.

[0224] Preferably, said sieve (III) has a mesh of at most 250 pm, preferably at most 200 pm, preferably at most 175 pm.

[0225] In a preferred embodiment, said sieve (III) has a mesh of at least 50 pm and at most 250 pm, preferably at least 75 pm and at most 200 pm, more preferably at least 100 pm and at most 175 pm, even more preferably at least 125 pm and at most 175 pm.

[0226] In a most preferred embodiment, the granulometric distribution of said AP composition is adjusted so that at most 20 wt.%, more preferably at most 15 wt.%, even more preferably at most 10 wt.%; even more preferably at most 6 wt.%, even more preferably at most 5 wt.% of said AP composition obtained in step (x) can pass through a third sieve (III) having a mesh of 150 pm. In yet another preferred embodiment, the granulometric distribution of said AP composition is adjusted so that:

[0227] • at least 99.0 wt.% of said AP composition obtained in step (x) can pass through a first sieve (I) having a mesh of 2.5 mm and

[0228] • at least 90.0 wt.% of said AP composition obtained in step (x) can pass through a second sieve (II) having a mesh of 1.4 mm.

[0229] • at most 10 wt.% of said AP composition obtained in step (x) can pass through a third sieve (III) having a mesh of 150 pm.

[0230] Preferably, said step (x) is carried out with at least one vibratory sieve or rotatory screen.

[0231] Preferably, said fractions (I) and / or (II) of said AP composition have substantially the same chemical composition as said AP composition.

[0232] Preferably, said fractions (I) and / or (II) of said AP composition comprise at least 50 wt.% of AP, more preferably at least 70 wt.% of AP, even more preferably at least 90 wt.% of AP, even more preferably at least 95 wt.% of AP, even more preferably at least 99 wt.% of AP, based on the total weight of said fraction of AP from said AP composition.

[0233] Preferably, said fractions (I) and / or (II) of said AP composition comprises at most 100 wt.% of AP.

[0234] Preferably, said fractions (I) and / or (II) essentially consists of AP. The expression “essentially consisting of’ is intended to denote that any additional ingredient in said fraction of AP, different from AP such as impurities, including for example water, insoluble salts, sulphates and / or fluorides are only present in a minor amount, typically, less than 3 wt.%, more advantageously less than 2 wt.%, even more advantageously less than 1 wt.%; being understood that said additional ingredients do not substantially modify the properties of said AP composition, i.e. do not materially affect the essential characteristics of said AP composition. Preferably, said fractions (I) and / or (II) of said AP composition can be added to said vessel (I). Thus, the vessel (I) enables the recycling of fine particles of AP of said AP composition that have been separated in step (x).

[0235] Step (xi) - Polyphosphate addition

[0236] According to the process of the present invention, at least one polyphosphate can be added to said vessel (I) and / or optionally said vessel (II).

[0237] Preferably, said at least one polyphosphate is selected from the group consisting of polyphosphates having the formula Xn+2PnO3n+i, polyphosphates having the formula XmPmOsm, and mixtures thereof, wherein n is an integer, preferably at least 2, and preferably at least 3, and m is an integer, preferably of at least 2, more preferably at least 3 and preferably at most 10 and X is selected from the group consisting of H, ammonium, alkali metals, alkali-earth metals and combinations thereof.

[0238] Non limiting example of polyphosphates include: polyphosphoric acid, potassium metaphosphate, potassium tripolyphosphate, potassium polyphosphate, sodium polyphosphate, sodium tripolyphosphate, sodium metaphosphates, sodium hexametaphosphate, sodium pentapolyphosphate, ammonium polyphosphate.

[0239] The polyphosphate may be crosslinked or linear or cyclic, preferably the polyphosphate is linear.

[0240] The inventors have surprisingly found that when a polyphosphate as described above is added to said vessel (I) and / or optionally said vessel (II), the caking of the AP composition obtained via the process of the present invention is reduced or absent.

[0241] Caking can be assessed by the method for measuring caking values described below.

[0242] Thus, when a polyphosphate is added as described above and below, said AP composition obtained by the process according to the present invention may have a caking value after 7 days in a closed cell of at most 25 N, preferably at most 23 N, more preferably at most 20 N, even more preferably at most 17 N, even more preferably at most 15 N.

[0243] Preferably, at least 0.01 wt.%, more preferably at least 0.05 wt.%, even more preferably at least 0.1 wt.%, more preferably at least 0.5 wt.%, even more preferably at least 1 wt.% of at least one polyphosphate is added to said vessel (I) and / or optionally said vessel (II) with regards to the total weight of the mixture contained in said vessel (I) and / or the slurry contained said vessel (II) or with regards to the total weight of the AP, preferably DAP and / or MAP, composition produced by said process. Preferably, at most 6 wt.%, more preferably at most 5 wt.%, more preferably at most 4 wt.%, even more preferably at most 3 wt.%, more preferably at most 2 wt.%, at most 1.5 wt.%, even more preferably at most 1 wt.% of at least one polyphosphate is added to said vessel (I) and / or optionally said vessel (II) with regards to the total weight of the mixture contained in said vessel (I) and / or said slurry contained said vessel (II) or with regards to the total weight of the AP, preferably DAP and / or MAP, composition produced by said process.

[0244] In a preferred embodiment, at least 0.01 wt.% and at most 5 wt.%, more preferably at least 0.05 wt.% and at most 5 wt.%, even more preferably at least 0.1 wt.% and at most 5 wt.%, more preferably at least 0.5 wt.% and at most 4 wt.%, even more preferably at least 1 wt.% and at most 3 wt.% of at least one polyphosphate is added to said vessel (I) and / or optionally said vessel (II) with regards to the total weight of the mixture contained in said vessel (I) and / or said vessel (II) or with regards to the total weight of the AP, preferably DAP and / or MAP, composition produced by said process.

[0245] It was observed that the addition of the polyphosphate as detailed above enables to reduce or suppress the caking of said AP composition obtained by the process according to the present invention. The present invention also concerns the use of said at least one polyphosphate, preferably as described above, in a process for producing a crystalline ammonium orthophosphate, preferably said process for producing a crystalline ammonium orthophosphate according to the present invention, as described above, in particular for reducing the caking of said AP composition.

[0246] Additional steps

[0247] The impurities present in the starting materials (the phosphoric acid composition and the ammoniacal source) are preferably present in the liquid phase.

[0248] Preferably, at least one fraction of the mixture of vessel (I) and / or the liquid phase of vessel (II) and / or the liquid phase of vessel (III) may be removed from said vessel (I) and / or (II) and / or (III). This removal may be done continuously or by fraction. It may be done by any means know in the art: by suction or by gravity and may be treated.

[0249] In some embodiments, TCP (tricalcium phosphate) can be added to the AP composition obtained by the process according to the present invention.

[0250] Each feature described above for any step and any given embodiment may be combined with any other feature of any other embodiments in any step of the present invention.

[0251] The present invention also concerns a crystalline ammonium phosphate, preferably as described above, preferably obtained or obtainable from the above process.

[0252] The present invention also concerns the use of at least one polyphosphate in a process for producing a crystalline ammonium orthophosphate, preferably as described above, in particular for reducing the caking of said AP composition. Method for measuring N / P molar ratio

[0253] Within the context of the present invention, all the N / P molar ratio values are measured by titration, preferably with a methrom titrator.

[0254] Method for measuring the F content

[0255] Within the context of the present invention, all the percentage by weight of fluor may be measured by any suitable method known in the art. All the F wt.% may be determined by direct potentiometry.

[0256] Method for measuring the SOs content

[0257] Within the context of the present invention, the weight percentages of SO3 (sulfur atoms expressed as SO3 equivalents) can be measured by any known method. For example, it can be by ICP (inductive couple plasma). It can also be done through turbidimetric measurement is carried out using a Metrohm-type photometer of the Metrohm type, which measures the attenuation of the intensity of a light beam of known wavelength passing through the suspension. Calibration with 5-barium chloride solutions is performed.

[0258] Method for measuring D10, D50 and D90

[0259] Within the context of the present invention, all the D10, D50 and D90 values can be measured by laser granulometry (Mastersizer Hydro 200S of Malvern) with 3 minutes ultrasonication in methanol.

[0260] A D10 is defined as a diameter expressed in pm for which 10 % by volume with regards to the total volume of particles, have smaller diameter than the D10 value. Thus, for example, a composition having a D10 of 30 pm means that 10 vol.% of the total volume of composition has a particle diameter smaller than 30 pm.

[0261] A D50 is defined as a diameter expressed in pm for which 50 % by volume with regards to the total volume of particles, have smaller diameter than the D50 value. Thus, for example, a composition having a D50 of 30 pm means that 50 vol.% of the total volume of composition has a particle diameter smaller than 30 pm. A D90 is defined as a diameter expressed in pm for which 90 % by volume with regards to the total volume of particles, have smaller diameter than the D90 value. Thus, for example, a composition having a D90 of 30 pm means that 90 vol.% of the total volume of composition has a particle diameter smaller than 30 pm.

[0262] Method for measuring P2O5 content

[0263] Within the context of the present invention all the P2O5 wt.% may be measured by any suitable method known in the art. Preferably all the P2O5 wt.% can be measured by colorimetry of phospho-vanado-molybdate at 436 nm (yellow) (Light absorption spectrophotometry). Before measurement, the sample can be dried at 45°C or 105°C, for example in a stove.

[0264] Method for determining iron content

[0265] Within the context of the present invention, all the ppm and wt.% of Fe can be determined by ICP (inductive couple plasma).

[0266] Method for determining aluminum content

[0267] Within the context of the present invention, all the ppm and wt.% of Al can be determined by ICP (inductive couple plasma).

[0268] Method for determining the insoluble matter content

[0269] Within the context of the present invention, all the insoluble matter wt.% can be determined as follows.

[0270] A clean filter membrane is dried in an oven at 45°C for 5 minutes. Said filter membrane has a pore diameter of 0.45 pm. A certain quantity WM of a sample for which the insoluble matter content must be determined, is added to a certain volume of water in a beaker. The water is at room temperature. The resulted mixture is stirred in said beaker for 15 minutes at room temperature. The mixture is then filtered through said dried filter membrane. The beaker is further rinsed several times (for example 2 times) with water at room temperature. The water used for rinsing the beaker is filtered on said filter membrane. The filter membrane is dried overnight at 45°C.

[0271] The content in weight percent of insoluble matter in the sample is determined as follows:

[0272] 100*(WMI-WM) / WS, wherein WMI is the weight (in g) of the dried membrane filter containing the insoluble matter; WM is the weight (in g) of the membrane filter after it was dried in an oven but before being used to filter the sample; WS is the weight of the sample for which the insoluble matter content must be determined.

[0273] Method for measuring the caking value

[0274] The caking test is carried out in two steps: a first step of consolidation of the powder into a solid mass followed by a quantitative evaluation. In the test, powders with a caking character are transformed into a cylindrical solidified mass whose hardness reflects the intensity of the caking behavior. The quantification of the caking is carried out by evaluating the force necessary to break the consolidated cylindrical mass. Firstly, the powder is subject to a compressive force for a fixed time. Hence, a mass of AP is homogeneously fed into a lined cylinder. The mass is first surmounted by a piston. In conditions that prevent exchanges with ambient air, the compression of 6 Kg is maintained for 7 days at room temperature (22-25°C). The assembly is then placed on a bench equipped with dynamometer (Mecmesin Multitest-d fitted with a AFG 500N dynamometer). A tip moves at a speed of 60 mm / sec and compresses the cylinder of consolidated powder. The dynamometer records the force progressively applied up to the point or rupture of the consolidated mass. The greater the force at rupture, the higher the tendency to display a powder caking behavior in real storage conditions. EXAMPLE 1 - PREPARATION OF CRYSTALLINE DAP WITH ADDITION OF

[0275] SHMP

[0276] In step (i), at least one phosphoric acid composition was mixed with at least one ammoniacal source in a first vessel (I) at a temperature of about 90-100 °C, thereby forming at least one mixture wherein said mixture has a N / P molar ratio comprised between 1.35 and 1.55 and a pH of at least 5.70 and at most 6.20; wherein N is the mol % of nitrogen atoms and P is the mol.% of phosphorus atoms; and wherein said phosphoric acid composition comprises, based on the total weight of said phosphoric acid composition, at least 58 wt.% and at most 65 wt.% of phosphorus expressed as P2O5 equivalents.

[0277] The ammoniacal source was a gas essentially consisting of ammonia. The phosphoric acid composition comprised, based on the total weight of said phosphoric acid composition:

[0278] . at least 100 and at most 1500 ppm of sulfur atoms expressed as SO3

[0279] • at least 1 and at most 100 ppm of F.

[0280] At least part of said mixture was transferred from said vessel (I) to at least one second vessel [hereafter, vessel (II)].

[0281] Thereafter, the N / P molar ratio of said mixture in said vessel (II) was adjusted to at least 1.85 and at most 2.00 by addition of an ammoniacal gas essentially consisting of ammonia, thereby forming at least one first slurry in said vessel (II). Said slurry comprised a solid residue comprising DAP and a liquid phase. Said slurry comprised at least 800 g and at most 1000 g of DAP per liter of slurry.

[0282] All of the slurry was transferred from said vessel (II) to a third vessel [hereafter, vessel (III)]. The vessel (III) was used for maturation of the crystalline DAP in said slurry. The mixture was transferred from said vessel (I) to said vessel (II) via overflow and the slurry was transferred from said vessel (II) to said vessel (III) via overflow. Said slurry comprised at least 800 g and at most 1000 g of DAP per liter of slurry.

[0283] The total residence time in said vessel (I), and said vessel (II) and said vessel (III) was of at least 12 hours and at most 21 hours.

[0284] The temperature of the slurry in said vessel (II) was of at least 50 °C and at most 100°C. The temperature of the slurry in said vessel (III) was of at least 50 °C and at most 100°C.

[0285] In step (v), said solid residue comprising DAP was separated from said liquid phase via centrifuge. The solid residue comprised between 90 wt.% and 95 wt.% of DAP and between 1 and 10 wt.% of water based on the total weight of said solid residue.

[0286] The obtained liquid phase was added in said vessel (I).

[0287] In step (vi), said solid residue was dried in a flash drier, thereby providing a DAP composition. The drying was carried out until the content of water fell below 1 wt.%.

[0288] The obtained AP composition essentially consisted of DAP. The DAP composition comprised at least 53 wt.% and at most 55 wt.% of phosphorus expressed as P2O5 equivalents.

[0289] The drying step comprised:

[0290] • a step (vi a) of providing a stream of gas (air) at a temperature of at least at least 110°C and at most 130 °C; and

[0291] • a step (vi b) of contacting said solid residue with said at least one stream of gas, during at least 10 seconds.

[0292] After drying, said DAP composition comprises, based on the total weight of said DAP composition:

[0293] • at most 0.1 wt.% of insoluble matter; and

[0294] • at most 75 ppm of iron; and

[0295] • at most 0.050 wt.% of fluor; and

[0296] • at most 500 ppm of Al; and • at most 1.0 wt.% of sulfur atoms expressed as SO3 equivalents; and

[0297] • at most 0.5, preferably at most 1 wt.% of water; and

[0298] • at least 97.0 wt.% and at most 100 wt.% of DAP.

[0299] The gas coming from the drying step (vi) was loaded with dusts.

[0300] The dusts were mostly made of particles of DAP having granulometry wherein more than 90 wt.% of dust particles can pass through a mesh sieve of 200 pm.

[0301] Therefore, a gas / solid separation step (viii) was carried out in a cyclonic separator, wherein most of said dust was removed from said gas, thereby providing:

[0302] • a treated gas, and

[0303] • dusts separated from said treated gas.

[0304] The dusts separated from said treated gas had sensibly the same chemical composition as the DAP composition. The obtained dusts were added into said vessel (I).

[0305] The treated gas was then washed with a solution comprising phosphoric acid, comprising at least 30 wt.% of phosphoric acid.

[0306] The solution resulting from the washing was added in said vessel (I).

[0307] The DAP composition obtained after the drying step was subjected to a granulometric adjustment. During this step, a first fraction of said DAP composition and a second fraction of said DAP composition were separated from said DAP composition, wherein said second fraction has a D50, higher than the D50 of said DAP composition and said first fraction has a D50 lower than the D50 of said DAP composition.

[0308] The granulometric distribution of said DAP composition was adjusted so that:

[0309] • at least at least 99 wt.% of said DAP can pass through a first sieve (I) having a mesh of 2.5 mm and • at least 94 wt.% of said DAP composition can pass through a second sieve (II) having a mesh of 1 .4 mm. at most 6 wt.% of said DAP composition can pass through a third sieve (III) having a mesh of 150 pm.

[0310] The obtained DAP composition had a D50 of 730 pm.

[0311] Said first fraction that was removed from said DAP composition were added in said vessel (I).

[0312] During the process, to avoid the building up of impurities, at least one fraction of the mixture of vessels (I), (II) and / or (III) may be removed from said vessels (I), (II) and / or (III).

[0313] At least 0.5 wt.% and at most 4 wt.% of sodium hexametaphosphate was added to said vessel (I), with regards to the total weight of the mixture contained in said vessel (I) and / or said vessel (II) and / or vessel (III) or with regards to the total weight of the DAP in said DAP composition produced by said process.

[0314] The obtained DAP composition had a caking value after 7 days in a closed cell of at most 20 N.

[0315] EXAMPLE 2- PREPARATION OF CRYSTALLINE DAP WITH ADDITION OF

[0316] POLYPHOSPHORIC ACID

[0317] In step (i), at least one phosphoric acid composition was mixed with at least one ammoniacal source in a first vessel (I) at a temperature of about 90-100 °C, thereby forming at least one mixture wherein said mixture has a N / P molar ratio comprised between 1.35 and 1.55 and a pH of at least 5.70 and at most 6.20; wherein N is the mol % of nitrogen atoms and P is the mol.% of phosphorus atoms; and wherein said phosphoric acid composition comprises, based on the total weight of said phosphoric acid composition, at least 58 wt.% and at most 65 wt.% of phosphorus expressed as P2O5 equivalents. The ammoniacal source was a gas essentially consisting of ammonia. The phosphoric acid composition comprised:

[0318] . at least 100 and at most 1500 ppm of sulfur atoms expressed as SO3

[0319] • at least 1 and at most 100 ppm of F.

[0320] Between 0 and 15 wt.% of crystalline AP were added into said vessel (I), with regards to the total of crystalline AP produced in said the process.

[0321] At least part of said mixture was transferred from said vessel (I) to at least one second vessel [hereafter, vessel (II)].

[0322] Thereafter, the N / P molar ratio of said mixture in said vessel (II) was adjusted to at least 1.85 and at most 2.00 by addition of an ammoniacal gas essentially consisting of ammonia, thereby forming at least one first slurry in said vessel (II). Said slurry comprised a solid residue comprising DAP and a liquid phase.

[0323] All of the slurry was transferred from said vessel (II) to a third vessel [hereafter, vessel (III)]. The vessel (III) was used for maturation of the crystalline DAP in said slurry. The mixture was transferred from said vessel (I) to said vessel (II) via overflow and the slurry was transferred from said vessel (II) to said vessel (III) via overflow. Said slurry comprised at least 800 g and at most 1000 g of DAP per liter of slurry.

[0324] The total residence time in said vessel (I), and said vessel (II) and said vessel (III) was of at least 12 hours and at most 21 hours.

[0325] The temperature of the slurry in said vessel (II) of at least 50 °C and at most 100°C. The temperature of the slurry in said vessel (III) of at least 50 °C and at most 100°C.

[0326] In step (v), said solid residue comprising DAP was separated from said liquid phase via centrifuge. The solid residue comprised between 90 wt.% and 95 wt.% of DAP and between 1 and 5 wt.% of water based on the total weight of said solid residue. The obtained liquid phase was added in said vessel (I).

[0327] In step (vi), said solid residue was dried in a flash drier, thereby providing a DAP composition. The drying was carried out until the content of water fall below 1 wt.%.

[0328] The obtained AP composition essentially consisted of DAP. The DAP composition comprised at least 53 wt.% and at most 55 wt.% of phosphorus expressed as P2O5 equivalents.

[0329] The drying step comprised:

[0330] • a step (vi a) of providing a stream of gas (air) at a temperature of at least at least 110°C and at most 130 °C; and

[0331] • a step (vi b) of contacting said solid residue with said at least one stream of gas, during at least 10 seconds.

[0332] After drying, said DAP composition comprises, based on the total weight of said DAP composition:

[0333] • at most 0.01 wt.% of insoluble matter; and

[0334] • at most 50 ppm of iron; and

[0335] • at most 0.050 wt.% of fluor; and

[0336] • at most 500 ppm of Al; and

[0337] • at most 1.0 wt.% of sulfur atoms expressed as SO3 equivalents; and

[0338] • preferably at most 0.1 wt.% of water; and

[0339] • at least 97.0 wt.% and at most 100 wt.% of DAP.

[0340] The gas coming from the drying step (vi) was loaded with dusts.

[0341] The dusts were mostly made of particles of DAP having granulometry wherein more than 90 wt.% of dust particles can pass through a mesh sieve of 200 pm.

[0342] Therefore, a gas / solid separation step (viii) was carried out in a cyclonic separator, wherein most of said dust was removed from said gas, thereby providing: • a treated gas, and

[0343] • dusts separated from said treated gas.

[0344] The dusts separated from said treated gas had sensibly the same chemical composition as the DAP composition. The obtained dusts were added into said vessel (I).

[0345] The treated gas was then washed with a solution comprising phosphoric acid, comprising at least 30 wt.% of phosphoric acid.

[0346] The solution resulting from the washing was added in said vessel (I), preferably as the at least one phosphoric acid composition

[0347] The DAP composition obtained after the drying step was subjected to a granulometric adjustment. During this step, a first fraction of said DAP composition and a second fraction of said DAP composition were separated from said DAP composition, wherein said second fraction has a D50, higher than the D50 of said DAP composition and said first fraction has a D50 lower than the D50 of said DAP composition.

[0348] The granulometric distribution of said DAP composition was adjusted so that:

[0349] • at least at least 99 wt.% of said DAP can pass through a first sieve (I) having a mesh of 2.5 mm and

[0350] • at least 94 wt.% of said DAP composition can pass through a second sieve (II) having a mesh of 1 .4 mm. at most 6 wt.% of said DAP composition can pass through a third sieve (III) having a mesh of 150 pm.

[0351] The obtained DAP composition had a D50 of 730 pm.

[0352] Said first fraction that was removed from said DAP composition were added in said vessel (I).

[0353] During the process, to avoid the building up of impurities, at least one fraction of the mixture of vessels (I), (II) and / or (III) may be removed from said vessels (I), (II) and / or (III). At least 1 wt.% and at most 5 wt.% of polyphosphoric acid was added to said vessel (I), with regards to the total weight of the mixture contained in said vessel (I) and / or said vessel (II) and / or vessel (III) or with regards to the total weight of the DAP in said DAP composition produced by said process.

[0354] The obtained DAP composition had a caking value after 7 days in a closed cell of at most 20 N.

[0355] From the above examples, the following effects were observed:

[0356] • the addition of polyphosphate enables to reduce or suppress caking of the DAP composition;

[0357] • the presence of the vessel (I) at the above defined N / P molar ratio enabled to recycle: o said liquid phase obtained in step (v) into said vessel (I), o the dusts obtained in step (viii) o fine DAP particles such as the fraction of the DAP composition obtained in step (x) after the granulometric adjustment, having a D50 lower than the D50 of the DAP composition.

[0358] The above effect shows that the process according to the present invention is efficient and versatile.

Claims

CLAIMS1 . A process for producing a crystalline ammonium orthophosphate [hereafter, AP] composition, preferably a DAP or MAP composition, comprising at least the steps of:(i). contacting at least one phosphoric acid composition and at least one ammoniacal source in at least one first vessel [hereafter, vessel (I)], thereby forming at least one mixture wherein said mixture has a N / P molar ratio comprised between 1.35 and 1.55 and a pH of at least 5.20 and at most 6.40, preferably at least 5.50 and at most 6.30, more preferably at least 5.70 and at most 6.20; wherein N is the mol % of nitrogen atoms and P is the mol.% of phosphorus atoms; and wherein said phosphoric acid composition comprises, based on the total weight of said phosphoric acid composition, at least 45 wt.% of phosphorus expressed as P2O5 equivalents;(ii). transferring at least part of said mixture from said vessel (I) to at least one second vessel [hereafter, vessel (II)],(iii). adjusting said N / P molar ratio of said mixture in said vessel (II) to either at least 1.70 and at most 2.30 or to at least 0.70 and at most 1.30, thereby forming at least one first slurry [hereafter, slurry] in said vessel (II); said slurry comprising a solid residue comprising AP and a liquid phase;(iv). optionally transferring at least part of said slurry from said vessel (II) to at least one third vessel [hereafter, vessel (III)];(v). separating at least part of said solid residue comprising AP from said liquid phase;(vi). drying said solid residue thereby obtaining an AP composition.

2. Process according to claim 1 , wherein at least one polyphosphate is added to said vessel (I) and / or said vessel (II); wherein said polyphosphate is selected from the group consisting of polyphosphateshaving the formula Xn+2PnO3n+i, polyphosphates having the formula XmPmOsm, and mixtures thereof, wherein n is an integer of at least 2, and preferably at least 3; and m is an integer of at least 2, more preferably at least 3, and at most 10; and X is selected from the group consisting of H, ammonium, alkali metals, alkali-earth metals and combinations thereof.

3. Process according to any one of the preceding claims, wherein said slurry comprises at least 500 g, preferably at least 600 g, more preferably at least 700 g, even more preferably at least 800 g of AP per liter of said slurry.

4. Process according to any one of the preceding claims, wherein said ammoniacal source is a gas comprising, based on the weight of said ammoniacal gas at least 75 wt.%, preferably at least 90 wt.%, preferably at least 95 wt.%, preferably at least 98 wt.% of ammonia.

5. Process according to any one of the preceding claims, wherein said AP composition comprises at least 50.0 wt.% of AP, more preferably at least 70.0 wt.% of AP, even more preferably at least 90.0 wt.% of AP, even more preferably at least 95.0 wt.% of AP, even more preferably at least 99.0 wt.% of AP, even more preferably at least 99.5 wt.%, even more preferably at least 99.9 wt.% of AP based on the total weight of said AP composition.

6. Process according to any one of the preceding claims, wherein said AP composition comprises, based on the total weight of said AP composition at least 45 wt.%, more preferably at least 50 wt.%, even more preferably at least 52 wt.% of phosphorus expressed as P2O5 equivalents.

7. Process according to any one of the preceding claims, wherein said AP composition comprises based on the total weight of said AP composition, at most 60 wt.%, more preferably at most 58 wt.%, even more preferably at most 56 wt.% of phosphorus expressed as P2O5 equivalents.

8. Process according to any one of the preceding claims, wherein said AP composition comprises, based on the total weight of said APcomposition, at most 0.50 wt.%, at most 0.10 wt.%, at most 0.05 wt.% of insoluble matter.

9. Process according to any one of the preceding claims, wherein said AP composition comprises, based on the total weight of said AP composition, at most 150 ppm, at most 100 ppm, at most 75 ppm, at most 50 ppm of iron.

10. Process according to any one of the preceding claims, wherein said AP composition comprises, based on the total weight of said AP composition at most 0.100 wt.%, preferably at most 0.075 wt.%, more preferably at most 0.050 wt.% of fluor.

11. Process according to any one of the preceding claims, wherein said AP composition comprises, based on the total weight of said AP composition, at most 1000 ppm, at most 750 ppm, at most 500 ppm of Al.

12. Process according to any one of the preceding claims, wherein said AP composition comprises, based on the total weight of said AP composition at most 2.5 wt.%, preferably at most 2.0 wt.%, more preferably at most 1.5 wt.%, even more preferably at most 1.0 wt.% of sulfur atoms expressed as SO3 equivalents.

13. Process according to any one of the preceding claims, said drying step (vi) is carried out until said AP composition obtained in step (vi) comprises at most 10 wt.%, preferably at most 5 wt.%, more preferably at most 2 wt.%, even more preferably at most 1 wt.% of water, based on the total weight of said AP composition.

14. Process according to any one of the preceding claims, wherein said phosphoric acid composition comprises, based on the total weight of said phosphoric acid composition, at least 50 wt.%, more preferably at least 58 wt.%, more preferably at least 60 wt.%, more preferably at least 62 wt.%, even more preferably at least 65 wt.% of phosphorus expressed as P2O5 equivalents.

15. Process according to any one of the preceding claims, wherein said phosphoric acid composition comprises, based on the total weight of said phosphoric acid composition, at most 75 wt.%, preferably at most 70 wt.%, preferably at most 67 wt.%, preferably at most 65 wt.%, even more preferably at most 60 wt.% of phosphorus expressed as P2O5 equivalents.

16. Process according to any one of the preceding claims, wherein the pH of said mixture in said vessel (I) is of at least 5.30, preferably at least 5.40, more preferably at least 5.50, even more preferably at least 5.60, even more preferably at least 5.70.

17. Process according to any one of the preceding claims, wherein the pH of said mixture in said vessel (I) is of at most 6.30, more preferably at most 6.20.

18. Process according to any one of the preceding claims, wherein said phosphoric acid composition comprises, based on the total weight of said phosphoric acid composition, at most 2000 ppm, preferably at most 1800 ppm, more preferably at most 1600 ppm, more preferably at most 1500 ppm of sulfur atoms expressed as SO3.

19. Process according to any one of the preceding claims, wherein said phosphoric acid composition comprises based on the total weight of said phosphoric acid composition at least 100 ppm, or at least 500 ppm of sulfur atoms expressed as SO3.

20. Process according to any one of the preceding claims, said phosphoric acid composition comprises based on the total weight of said phosphoric acid composition at most 700 ppm, preferably at most 650 ppm, more preferably at most 550 ppm, even more preferably at most 500 ppm, of F.

21. Process according to any one of the preceding claims, wherein said step (i) of contacting at least one phosphoric acid composition and at least one ammoniacal source is carried out at a temperature of at least 40°C and preferably at most 100°C, more preferably at least 50 °C and preferably at most 100 °C.

22. Process according to any one of the preceding claims, wherein in step (iii), the N / P molar ratio of said mixture in said vessel (II) is adjusted to at least 1.70 and at most 2.30, preferably at least 1.80 and at most 2.10, and said process is a process for producing crystalline diammonium orthophosphate.

23. Process according to any one of claims 1 to 22, wherein in step (iii), the N / P molar ratio of said mixture in said vessel (II) is adjusted to at least 0.70 and at most 1.30, preferably at least 0.90 and at most 1.20, and said process is a process for producing crystalline monoammonium orthophosphate.

24. Process according to any one of the preceding claims, wherein said slurry comprises at least 500 g, preferably at least 600 g, more preferably at least 700 g, even more preferably at least 800 g of AP per liter of slurry.

25. Process according to any one of the preceding claims, wherein said slurry comprises at most 1500 g, more preferably at most 1300 g, even more preferably at most 1200 g, even more preferably at most 1100 g, even more preferably at most 1000 g of AP per liter of slurry.

26. Process according to any one of the preceding claims, wherein in step (iii) said the N / P molar ratio of said mixture in said vessel (II) is adjusted by addition in said vessel (II) of at least one ammoniacal source and / or at least one phosphoric acid composition.

27. Process according to any one of the preceding claims, wherein the temperature of said slurry in said vessel (II) is of at least 40 °C, preferably at least 45 °C, more preferably at least 50°C.

28. Process according to any one of the preceding claims, wherein the temperature of said slurry in said vessel (II) is of at most 130 °C, preferably at most 120°C, more preferably at most 100 °C.

29. Process according to any one of the preceding claims, wherein said solid residue comprises at least 45 wt.%, more preferably at least 50 wt.%, even more preferably at least 55 wt. %, even more preferably at least 70 wt.%, even more preferably at least 80 wt.%, even more preferably at least 90 wt.% of AP, based on the total weight of said solid residue.

30. Process according to any one of the preceding claims, wherein said solid residue comprises at least 1 wt.%, more preferably at least 3 wt.%, even more preferably at least 5 wt.% of water, based on the total weight of said solid residue.

31. Process according to any one of the preceding claims, wherein said solid residue comprises at most 30 wt.%, more preferably at most 20 wt.%, even more preferably at most 10 wt.% of water, based on the total weight of said solid residue.

32. Process according to any one of the preceding claims, wherein said AP composition obtained by said process comprises at least 50 wt.% of AP, more preferably at least 70 wt.% of AP, even more preferably at least 90 wt.% of AP, even more preferably at least 95 wt.% of AP, even more preferably at least 99 wt.% of AP, based on the total weight of said AP composition.

33. Process according to any one of the preceding claims, wherein said drying step (vi), preferably comprise:• at least a step (vi a) of providing at least one stream of gas, preferably air, at a temperature of at least 80 °C, preferably at last 90°C, more preferably at least 100°C, even more preferably at least 110°C; and• at least a step (vi b) of contacting said solid residue with said at least one stream of gas, during at least 1 second, more preferably at least 5 seconds, even more preferably at least 10 seconds, even more preferably at least 30 seconds, even more preferably least 1 minute, even more preferably at least5 minutes, even more preferably at least 10 minutes, even more preferably at least 30 minutes, even more preferably at least 1 hour, even more preferably at least 2 hours; thereby providing at least a gas comprising dusts comprising dust particles, preferably of AP such as DAP and / or MAP; said dusts preferably having a granulometry wherein at least 90 wt.% of said dust particles can pass through a mesh sieve of 500 pm or 400 pm, or 300 pm, or 200 pm.

34. Process according to claim 33, wherein said process further comprises a gas / solid separation step (viii) wherein at least part of said dusts are removed from said gas, thereby providing:• a treated gas, and• dusts separated from said treated gas.

35. Process according to claim 34, wherein said process further comprises a step of adding at last part of said dusts separated from said treated gas into said vessel (I).

36. Process according to any one of the preceding claims, wherein said process further comprises at least one step (x) of separating at least one first fraction of said AP composition and optionally at least one second fraction of said AP composition, wherein said at least one second fraction has an average particle size, preferably a D50, higher than the average particle size, preferably a D50 of said AP composition and said at least one first fraction of AP has an average particle size, preferably a D50 lower than the average particle size, preferably the D50 of said AP composition, thereby adjusting the granulometric distribution of said AP composition.

37. Process according to claim 10, wherein the granulometric distribution of said AP composition is adjusted in step (x) so that:• at least at least 99.0 wt.% of said AP composition obtained in step (x) can pass through a first sieve (I) having a mesh of 2.5 mm andat least 90.0 wt.% of said AP composition obtained in step (x) can pass through a second sieve (II) having a mesh of 1.4 mm.• at most 10 wt.% of said AP composition obtained in step (x) can pass through a third sieve (III) having a mesh of 150 pm.

38. Process according to claim 36 or 37, wherein at least part of said first and / or said second fraction is added into said vessel (I).

39. Process according to any one of the preceding claims, wherein at least part of said liquid phase obtained in step (v) is added into said vessel (I) and / or said vessel (II).

40. Use of at least one polyphosphate, preferably selected from the group consisting of polyphosphates having the formula Xn+2PnO3n+i, polyphosphates having the formula XmPmOsm, and mixtures thereof, wherein n is an integer of at least 2, and preferably at least 3, and m is an integer of at least 2, more preferably at least 3, and at most 10, and X is selected from the group consisting of H, ammonium, alkali metals, alkali- earth metals and combinations thereof, in a process for producing a crystalline AP composition preferably a process according to any one of the preceding claims, for reducing the caking of said AP composition.

41. Use according to claim 40, wherein said crystalline AP composition has a caking value after 7 days in a closed cell of at most 25 N, preferably at most 23 N, more preferably at most 20 N, even more preferably at most 17 N, even more preferably at most 15 N.

42. Ammonium orthophosphate composition obtained by the process according to any one of claims 1 to 39.