Polyhalite Granules

Abstract

The present invention provides a granular material comprising a polyhalite composition; 0.2% (w / w) to 2.0% (w / w) organic binder and 0.5% (w / w) to 6.0% (w / w) inorganic binder, wherein the ratio of inorganic binder to organic binder is greater than 1:1, as well as a process for preparing the material. The present invention further provides granules comprising polyhalite or polyhalite in combination with potassium salt(s), having a crushing strength of 2.0 kgf to 6.0 kgf and a final moisture content of 0.25 to 0.50% w / w.

Description

[Technical Field]

[0001] introduction The present invention relates to polyhalite granules and processes for their manufacture. The polyhalite granules comprise polyhalite and / or polyhalite together with a potassium salt, for example from a potash source, an organic binder, and an inorganic binder. [Background technology]

[0002] Background of the Invention Polyhalite granulation is a process that performs well when granulated without a binder or with an organic binder. However, a problem occurs when polyhalite granules have a high water uptake, which significantly reduces the crushing strength of the granulated product and leads to high levels of degradation and dust generation, even when no fine particles were present in the original granulated product. The aforementioned drawbacks occur particularly when starch is used as a binder due to the hygroscopic nature of starch, resulting in granules that degrade under humid conditions. As such, a limitation of polyhalite granules with starch as a binder is that the physical integrity of the granules is poor during long-term transportation, handling, and storage. Starch only provides physical interaction, not chemical interaction, and such physical interaction deteriorates over time and due to the action of microorganisms.

[0003] There is a need for polyhalite granules to remedy the above-mentioned problems. Summary of the Invention

[0004] According to a first aspect of the present invention: Polyhalite compositions; 0.2% (w / w) to 2.0% (w / w) of an organic binder; and 0.5% (w / w) to 6.0% (w / w) of an inorganic binder, wherein Inorganic binders with a ratio of inorganic binder to organic binder greater than 1:1 A granular material is provided comprising:

[0005] The ratio of inorganic binder to organic binder can be greater than 1:1 to about 10:1, typically about 2:1 to 10:1, and preferably about 3:1 to 8:1, in other words, there is more inorganic binder than organic binder.

[0006] The polyhalite composition may include polyhalite or polyhalite in combination with potassium salt(s). The polyhalite composition may consist essentially of polyhalite. The polyhalite composition may consist of polyhalite.

[0007] The polyhalite composition may be 8.0% (weight to weight) (w / w) to 98.0% (w / w) polyhalite in combination with 92.0% (w / w) to 2.0% (w / w) potassium salt(s); 30.0% (w / w) to 80.0% (w / w) polyhalite in combination with 70.0% (w / w) to 20.0% (w / w) potassium salt(s); and preferably 50.0% (w / w) to 80.0% (w / w) polyhalite in combination with 50.0% (w / w) to 20.0% (w / w) potassium salt(s). The polyhalite may comprise from 50.0% (w / w) to 70.0% (w / w) polyhalite in combination with 50.0% (w / w) to 30.0% (w / w) potassium salt(s), more preferably from 50.0% (w / w) to 70.0% (w / w) polyhalite in combination with 50.0% (w / w) to 30.0% (w / w) potassium salt(s), more preferably from 60.0% (w / w) to 70.0% (w / w) polyhalite in combination with 40.0% (w / w) to 30.0% (w / w) potassium salt(s), and typically about 65.0% (w / w) polyhalite in combination with 35.0% (w / w) potassium salt(s).

[0008] The potassium salt(s) may be selected from potassium chloride, potassium nitrate, potassium sulfate or a combination thereof, preferably potassium chloride.

[0009] The organic binder can be native starch, modified starch, pregel starch (pregel starch is starch that has been precooked and dried to enhance its thickening and water absorption capacity at lower temperatures), corn, potato, manioc, tapioca, rice starch, or any combination thereof, hydrogel, carboxymethylcellulose, magnesium lignosulfonate, sodium lignosulfonate, calcium lignosulfonate, and chitosan, or any combination thereof. The starch can be pretreated with sodium hydroxide (NaOH) to promote the low-temperature gelatinization of the starch and the resulting change in the rheological profile.

[0010] In a preferred embodiment of the present invention, the organic binder is carboxymethyl cellulose, which may have a weight of from about 90,000 to about 750,000 (inclusive).

[0011] The inorganic binder may be selected from gypsum, anhydrite, Na-bentonite, magnesium oxideplaster of paris, simple superphosphate, magnesium phosphate, aluminum silicate, sodium silicate, potassium silicate, kaolin, mica, syngenite, other forms of polyhalite (including calcined polyhalite, hydrated polyhalite), magnesium sulfate, or combinations thereof.

[0012] Preferred inorganic binders are gypsum alpha-hemihydrate or beta-hemihydrate, anhydrite, magnesium oxide, simple superphosphate, magnesium phosphate, syngenite, forms of polyhalite (including calcined polyhalite, hydrated polyhalite), magnesium sulfate (both as anhydrous and in monohydrate form) or combinations thereof, preferably gypsum alpha-hemihydrate.

[0013] The particulate material (granules) may further include boron, such as borax, colemanite, ulexite, or any combination thereof, and / or zinc oxide or zinc sulfate.

[0014] Boron may be present in an amount of 0.1% (w / w) to 1.0% (w / w), preferably 0.2% (w / w) to 0.8% (w / w) and even more preferably 0.3% (w / w) to 0.5% (w / w).

[0015] Zinc may be present in an amount of 0.1% (w / w) to 1.0% (w / w), preferably 0.1% (w / w) to 0.5% (w / w) and even more preferably 0.1% (w / w) to 0.3% (w / w).

[0016] The polyhalite granules may typically have a particle size range of 1.0 mm to 6.0 mm, preferably 2.5 mm to 4.0 mm, and even more preferably 2.7 mm to 3.1 mm.

[0017] The average particle size of the polyhalite granules is from 1 mm to 1.9 mm, preferably from 2 mm to 2.4 mm, preferably from 2.5 mm to 3.5 mm, preferably from 2.6 mm to 3.1 mm, and even more preferably from 2.70 mm to 2.80 mm.

[0018] The polyhalite granules according to the present invention may have a crush strength of about 2 kgf to about 6 kgf, more preferably about 2.5 kgf to about 5 kgf, and most preferably about 3.0 kgf to about 4 kgf. In one embodiment of the present invention, the polyhalite granules have a crush strength of above about 5 kgf.

[0019] Without being bound by theory, applicants believe that the above parameters result in an improved product with improved abrasion resistance and improved coating properties (i.e., ability to be coated). This is believed to be due to the granules assuming a smoother, more spherical shape that is easier to coat and less susceptible to abrasion. In this regard, it is preferred that the inorganic portion of the binder be larger than the organic portion.

[0020] According to a second aspect of the present invention, there is provided a process for the preparation of polyhalite granules according to the first aspect of the present invention, said process comprising: (a) (i) a polyhalite composition; (ii) 0.2% (w / w) to 2.0% (w / w) of an organic binder; (iii) 0.5% (w / w) to 6.0% (w / w) inorganic binder, wherein the ratio of inorganic binder to organic binder is greater than 1:1; and (iv) 0% (w / w) to 14% (w / w) water to obtain a polyhalite mixture; and (b) granulating the polyhalite mixture to produce polyhalite granules. A process is provided which includes the steps of:

[0021] The polyhalite composition may be added to a granulator to produce polyhalite granules.

[0022] The ratio of inorganic binder to organic binder can be greater than 1:1 to about 10:1, typically about 2:1 to 10:1, and preferably about 3:1 to 8:1, in other words, there is more inorganic binder than organic binder.

[0023] The polyhalite composition may include polyhalite or polyhalite in combination with potassium salt(s). The polyhalite composition may consist essentially of polyhalite. The polyhalite composition may consist of polyhalite.

[0024] The polyhalite composition may be 8.0% (weight to weight) (w / w) to 98.0% (w / w) polyhalite in combination with 92.0% (w / w) to 2.0% (w / w) potassium salt(s); 30.0% (w / w) to 80.0% (w / w) polyhalite in combination with 70.0% (w / w) to 20.0% (w / w) potassium salt(s); and preferably 50.0% (w / w) to 80.0% (w / w) polyhalite in combination with 50.0% (w / w) to 20.0% (w / w) potassium salt(s). The polyhalite may comprise from 50.0% (w / w) to 70.0% (w / w) polyhalite in combination with 50.0% (w / w) to 30.0% (w / w) potassium salt(s), more preferably from 50.0% (w / w) to 70.0% (w / w) polyhalite in combination with 50.0% (w / w) to 30.0% (w / w) potassium salt(s), more preferably from 60.0% (w / w) to 70.0% (w / w) polyhalite in combination with 40.0% (w / w) to 30.0% (w / w) potassium salt(s), and typically about 65.0% (w / w) polyhalite in combination with 35.0% (w / w) potassium salt(s).

[0025] The potassium salt(s) may be selected from potassium chloride, potassium nitrate, potassium sulfate or a combination thereof, preferably potassium chloride.

[0026] The organic binder can be native starch, modified starch, pregel starch (pregel starch is starch that has been precooked and dried to enhance its thickening and water absorption capacity at lower temperatures), corn, potato, manioc, tapioca, rice starch, or any combination thereof, hydrogel, carboxymethylcellulose, magnesium lignosulfonate, sodium lignosulfonate, calcium lignosulfonate, and chitosan, or any combination thereof. The starch can be pretreated with sodium hydroxide (NaOH) to promote the low-temperature gelatinization of the starch and the resulting change in the rheological profile.

[0027] In a preferred embodiment of the present invention, the organic binder is carboxymethyl cellulose, which may have a weight of from about 90,000 to about 750,000 (inclusive).

[0028] The inorganic binder may be selected from gypsum, anhydrite, Na-bentonite, magnesium oxideplaster of paris, simple superphosphate, magnesium phosphate, aluminum silicate, sodium silicate, potassium silicate, kaolin, mica, syngenite, other forms of polyhalite (including calcined polyhalite, hydrated polyhalite), magnesium sulfate, or combinations thereof.

[0029] Preferred inorganic binders are gypsum alpha-hemihydrate or beta-hemihydrate, anhydrite, magnesium oxide, simple superphosphate, magnesium phosphate, syngenite, forms of polyhalite (including calcined polyhalite, hydrated polyhalite), magnesium sulfate (both as anhydrous and in monohydrate form) or combinations thereof, preferably gypsum alpha-hemihydrate.

[0030] The particulate material (granules) may further include boron, such as borax, colemanite, ulexite, or any combination thereof, and / or zinc oxide or zinc sulfate.

[0031] Boron may be present in an amount of 0.1% (w / w) to 1.0% (w / w), preferably 0.2% (w / w) to 0.8% (w / w) and even more preferably 0.3% (w / w) to 0.5% (w / w).

[0032] Zinc may be present in an amount of 0.1% (w / w) to 1.0% (w / w), preferably 0.1% (w / w) to 0.5% (w / w) and even more preferably 0.1% (w / w) to 0.3% (w / w).

[0033] The process according to this aspect of the invention may have a granulation efficiency of at least about 40%, more preferably about 55% and more preferably about 70%.

[0034] Granulation efficiency is the % of granules that achieve a size that is considered an acceptable product at the end of the granulator. For the present invention, particles between 4mm and 2mm are considered preferred.

[0035] The polyhalite granules produced in step (b) may be dried in a drying apparatus.

[0036] According to a third aspect of the present invention, there is provided a granule comprising polyhalite in combination with potassium salt(s) having a crushing strength of from 2.0 kgf to 6.0 kgf and a final moisture content of from 0.25 to 0.50% w / w. [Brief explanation of the drawings]

[0037] The present invention will be more fully understood from the detailed description provided herein and from the accompanying figures and results, which are given by way of example only and do not limit the intended scope of the invention. [Figure 1] FIG. 1 is a flow diagram of the process for producing polyhalite granules of the present invention; [Figure 2] Figure 2 shows polyhalite + potassium chloride (65:35 w / w) granules produced by experiments 3, 14 and 14'; [Figure 3] Figure 3 shows polyhalite + potassium chloride (65:35 w / w) granules produced by experiments 5, 15 and 16; [Figure 4] Figure 4 shows polyhalite + potassium chloride (65:35 w / w) granules produced by experiments 19 and 20; [Figure 5] Figure 5 shows polyhalite + potassium chloride (65:35 w / w) granules produced by experiments 4, 21, 22, 23, 24, 25, 26 and 29; [Figure 6] Figure 6 shows polyhalite + potassium chloride (65:35 w / w) granules produced by experiments 17 and 18; [Figure 7]Figure 7 is polyhalite + potassium chloride (65:35 w / w) granules produced by experiment 32; [Figure 8] Figure 8 is a graph showing granulation efficiency (%) and crushing strength (kgf) for experiments 1 to 32; [Figure 9] Figure 9 shows the treatment conditions for further experiments; [Figure 10] FIG. 10 shows the properties of the polyhalite granules produced in further experiments 03, 04 and 05. DETAILED DESCRIPTION OF THE INVENTION

[0038] DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to the granulation of polyhalite (polyhalite is a hydrated evaporite mineral consisting of sulfates of potassium, calcium, and magnesium with the formula KCaMg(SO)·2H0) or polyhalite in combination with potassium salts (chlorides of potash), preferably potassium chloride, using a combination of organic and inorganic materials as binders to improve granulation and final product quality. The organic and inorganic additives or binders can be in either a solid or liquid phase. The liquid phase can be a suspension in water or a dilute material. Starch can also be pretreated in sodium hydroxide solution. Granulation can be effected in a drum, pan, fluidized bed, high shear, extruder, paddle mix, spheronizer, or any other type of granulator. Granulation can be carried out with or without steam, preferably at a temperature of at least 30°C (Celsius).

[0039] The present invention can reduce dust generation and minimize the loss of crushing strength over time. Better shaped granules, such as rounder particles, can also be produced. The combination of inorganic and organic binders can reduce the moisture uptake and / or its kinetics of the final product. Furthermore, this can also reduce the dependency on the need for high doses of other additives / chemicals, such as coatings, which only help prevent deterioration of the granules once they are produced.

[0040] The organic binder aids in the granulation process by binding the polyhalite and potassium salt together during agglomeration, and may be selected from native starch, modified starch, pregel starch (pregel starch is starch that has been precooked and dried to enhance its thickening and water absorption capacity at lower temperatures), corn, potato, manioc, tapioca, rice starch, or any combination thereof, hydrogel, carboxymethylcellulose, magnesium lignosulfonate, sodium lignosulfonate, calcium lignosulfonate, and chitosan, or any combination thereof. The starch may be pretreated with sodium hydroxide (NaOH) to promote the low-temperature gelatinization of the starch and the resulting change in its rheological profile. In a preferred embodiment of the present invention, the organic binder is carboxymethylcellulose. The carboxymethylcellulose may have a weight of about 90,000 to about 750,000 (inclusive).

[0041] According to the process of the present invention, it has been discovered that the combination of an organic binder with an inorganic binder improves not only the granulation process but also the crushing strength. Surprisingly, it has been discovered that gypsum, a soft sulfate mineral composed of calcium sulfate dihydrate, having the chemical formula CaSO4·2H2O, increases the granulation efficiency of the process and produces high crushing strength. Without wishing to be bound by theory, the increase in crushing strength is believed to be due to the formation of crystal bridges through mineral reaction or hydration, which surprisingly occurs without the presence of an acid for the reaction to occur. Alpha-hemihydrate gypsum is preferred due to its crystalline structure. Beta-hemihydrate consists of fine aggregates. In contrast, alpha-hemihydrate consists of coarse particles with well-defined crystals. Other inorganic binders that are expected to work similarly are anhydrite, magnesium oxide, simple superphosphate, magnesium phosphate, syngenite, forms of polyhalite (including calcined polyhalite, hydrated polyhalite), magnesium sulfate (both as anhydrous and in monohydrate form), or combinations thereof.

[0042] The ratio of binders contained in the granules has a surprising effect on the granules, where the best of each binder can be achieved when the correct ratio between organic and inorganic binders is added in the granulation. This can mean achieving higher crushing strength (using organics) and compacted and smooth particles and easier granulation (using inorganics). The organic:inorganic ratio will depend on the inorganic binder chosen. Organic binders are used at 1.5% w / w or less, while inorganic binders can reach loadings of up to 6% w / w. A more suitable inorganic:organic binder ratio appears to be between 3:1 and 8:1.

[0043] Granulation efficiency is the % of granules that achieve a size that is considered an acceptable product at the end of the granulator. For the present invention, particles between 4mm and 2mm are considered preferred.

[0044] The polyhalite granules according to the present invention may have a crush strength of about 2 kgf to about 6 kgf, more preferably about 2.5 kgf to about 5 kgf, and most preferably about 3.0 kgf to about 4 kgf. In one embodiment of the present invention, the polyhalite granules have a crush strength of above about 5 kgf.

[0045] The kilogram-force (kgf) is the metric unit of force, and is 9.80665 m / s 2 The force is equal to the force exerted on a mass of 1 kilogram in a gravitational field of 1. Thus, 1 kilogram-force is equal to 9.80665 Newtons.

[0046] Crushing strength is a measure of the resistance of granules to deformation or cracking under pressure. Crushing strength is of interest in estimating the expected handling and storage characteristics of granular materials and in determining the pressure limits to be applied during bag and bulk storage. A preferred procedure states that more than 25 granules (usually 30) between 2.36 mm and 2.79 mm are subjected to pressure until breakage is observed. The force applied to break the granules is the crushing strength (Granule Crushing Strength - IFDC Methodology S-115).

[0047] The granules further: Potassium sulfate, potassium chloride, langbeinite, potassium nitrate, etc. Sulfur (elemental sulfur, ammonium sulfate), and ·urea The nutrients may include macronutrients / micronutrients selected from:

[0048] Optional additional ingredients to the granules are: Boron (borax, colemanite, ulexite), Zinc (zinc oxide, zinc sulfate), and Magnesium (magnesium oxide, kieserite, magnesite) It can be one or more of: [Example]

[0049] Figure 1 shows the schematic process for each of the experiments. Figure 1 illustrates a process (10) for preparing polyhalite granules according to the present invention, in which a mixture of polyhalite (2), polyhalite and potassium salt (4), and a mixture of organic and inorganic binders (6) together with water (8) is added to an Eirich (RTM) intensive mixer (12) and then transferred to a pan granulator (16) (14). It will be appreciated that different granulation equipment can be used, such as a drum granulator, pan granulator, Eirich (RTM) high share, spheronizer, fluidized bed, or any other type or combination of equipment capable of producing granules. The wet granules are then transferred to a dryer (20) (18).

[0050] Drying conditions should be around 100°C, although it can also be done at lower temperatures (e.g., 70-95°C), but should not be higher than about 120°C to avoid decomposition or caramelization of the organic material.

[0051] Following drying, polyhalite granules (20) according to the present invention are produced. The granulation efficiency can be greater than 70-80% and the crushing strength can be greater than 4 kgf (39.23 N).

[0052] 32 experiments were performed with different binders and combinations added as follows, see Figure 8.

[0053] Water is used at 90 degrees Celsius for all experiments.

[0054] · Experiments 1, 1' and 12 - No binder No binder was used to produce the polyhalite and potassium chloride granules. Polyhalite and potassium chloride (65:35 w / w); and water at a temperature of 90°C were used in the granulation process to produce the polyhalite and potassium chloride granulates. The crushing strength of the granules for all three experiments was 1.7 kgf (16.67 N), and the granulation efficiency varied with the process conditions and the amount of water added during granulation.

[0055] [Table 1]

[0056] · Experiment 3, 14 and 14'-pregel cornstarch Polyhalite granules were produced using polyhalite, potassium chloride, pregel cornstarch, and water at a temperature of 90°C in a granulation process. The crushing strength of the granules was 3.7 kgf (36.28 N) and was reached when water was added at 7 wt% (Run 14'). Runs 3 and 14 did not produce granules with the desired particle size distribution (9% and 7.5% water added, respectively) and had roughness on the surface of the granules. The granulated polyhalite and potassium chloride product is shown in Figure 2.

[0057] [Table 2]

[0058] · Experiments 5, 15 and 16 - α-HH gypsum Granules of polyhalite and potassium chloride were produced using polyhalite, potassium chloride, α-HH gypsum, and water levels of 7.2, 7.0, and 7.5% in the granulation process for Experiments 5, 15, and 16, respectively. Crushing strength was very low, around -0.6 to 0.7 kgf (5.88 to 6.86 N). The granules were smooth and easy to granulate. α-HH gypsum was observed to offer lower hygroscopic behavior. The granulated polyhalite products are shown in Figure 3.

[0059] [Table 3]

[0060] · Experiments 19 and 20 - Bentonite and Starch Previous experience has shown that bentonite aids in granulation but not crushing strength. Starch has been added in combination with bentonite to aid in crushing strength. Polyhalite, potassium chloride, bentonite, starch, and water have been used in a granulation process to produce polyhalite and potassium chloride granules. The use of different organic and inorganic binders positively affected product hardness, granulation behavior, and the physical aspects of the final product.

[0061] [Table 4]

[0062] The resulting granulations did not reach the best liquid phase conditions. Granulation efficiency can be improved by changing the process conditions. The highest crushing strength was found in Experiment 19, which was 4.5 kgf (44.13 N).

[0063] The granulated polyhalite product is shown in FIG.

[0064] · Experiments 4, 21, 22, 23, 24, 25, 26 and 29 - ArrMaz Binder TM Polyhalite and potassium chloride, ArrMaz Binder TM (organic binder containing carboxymethyl cellulose), and water were used in the granulation process to produce granules of polyhalite and potassium chloride. TM " should be considered a registered trademark (RTM) designation). The granulation was successful due to the behavior of the binder. Small changes in granulation temperature seemed to have an effect on the granulation efficiency and the behavior of the product, which changed from being very difficult to granulate (only fine particles formed) to being very easy and fast to granulate, resulting in large dry balls in a few seconds after the addition of a small amount of water. The granulation curve appeared to be very small, going from fine to coarse particles very easily. The particles formed did not have a smooth surface, but despite this the binder had a positive effect on the crushing strength of the final product.

[0065] [Table 5]

[0066] The granulated polyhalite product is shown in FIG.

[0067] · Experiments 17, 18 and 32 - α-HH Gypsum and Starch Polyhalite, potassium chloride, α-HH gypsum, starch, and water were used in a granulation process to produce polyhalite and potassium chloride granules. They exhibited easier granulation behavior, high crushing strength (3.7, 3.6, and 2.0 kgf (36.28, 35.30; 19.61 N) for Runs 17, 18, and 32, respectively), and granulation efficiencies between 39 and 50%. The resulting polyhalite and potassium chloride mixture particles were rounder and easier to granulate than those produced using pregel cornstarch alone. The polyhalite and potassium chloride granules also had good crushing strength (which was not achieved with α-HH gypsum alone). The granulated polyhalite products are shown in Figures 6 and 7.

[0068] The use of different organic and inorganic binders affected the product hardness, granulation behavior and physical aspects of the final product.

[0069] [Table 6]

[0070] · Experiment 31 - α-HH Gypsum and ArrMAz Binder TM Polyhalite, potassium chloride, α-HH gypsum, ArrMaz Binder TMand water were used in the granulation process to produce granules of polyhalite and potassium chloride. The organic:inorganic binder ratio and process conditions can be manipulated to achieve the highest crushing strength, best physical characteristics, and higher granulation efficiency. Preliminary results suggest that the organic:inorganic ratio will depend on the inorganic binder chosen. Organic binders are used at 1.5% w / w or less, while inorganic binders can reach loadings of up to 6% w / w. A more suitable inorganic:organic binder ratio appears to be between 3:1 and 8:1.

[0071] [Table 7]

[0072] The use of different organic and inorganic binders affected the product hardness, granulation behavior and physical aspects of the final product.

[0073] Based on the above experiments, further experiments were carried out to understand the granulation behavior, crushing strength, liquid phase, product characteristics and granulation efficiency by varying the ratio between organic binder and inorganic binder. In this case, α-HH gypsum and ArrMaz Binder TM The following combinations were chosen. A central composite design (CCD) with two variables (organic:inorganic binder ratio and water addition) was run with two replicates at the center point. The granulation time used to run the experiment was fixed at 7 minutes (4 minutes in an intensive force mixer and 3 minutes in a pan granulator), the ratio of polyhalite to potassium chloride was the same for all CCDs (polyhalite:potassium chloride - 65:35), and the mixture during granulation, liquid addition, and compression times were also fixed. The processing conditions for further experiments are shown in Figure 9.

[0074] The results for the polyhalite and potassium chloride granule products are shown in Figure 10. Unfortunately, all CCD runs except for runs 3, 4, and 5 resulted in fine or coarse particles, and it was not possible to characterize the final products or proceed with statistical evaluation. The granulated polyhalite and potassium chloride products are shown in Figure 11.

[0075] [Table 8]

[0076] Based on the results, the ratio of binders contained in the granules has a surprising effect on the granules, where the best of each binder can be achieved when the correct ratio between organic and inorganic binders is added in the granulation, which can mean reaching higher crushing strength (using organics) and compacted and smooth particles and easier granulation (using inorganics).

[0077] · Experiments 32-35: Polyhalite with inorganic and organic binders. Polyhalite (100%) with a combination of organic / inorganic binders and water was used in a granulation process to produce polyhalite granules. The organic:inorganic binder ratio and process conditions can be manipulated to achieve the highest crushing strength, best physical characteristics, and higher granulation efficiency. Preliminary results suggest that the organic:inorganic ratio will depend on the inorganic binder chosen. Organic binders are used at 1.5% w / w or less, while inorganic binders can reach loadings of up to 6% w / w. A more suitable ratio is a ratio of inorganic binder to organic binder greater than 1:1.

[0078] [Table 9]

Claims

1. i. a polyhalite composition; ii. 0.2% (w / w) to 2.0% (w / w) of an organic binder; and iii. 0.5% (w / w) to 6.0% (w / w) of an inorganic binder; an inorganic binder, the ratio of inorganic binder to organic binder being greater than 1:1; , including granular materials.

2. 10. The material of claim 1, wherein the ratio of inorganic binder to organic binder is greater than 1:1 to about 10:

1.

3. 3. The material of claim 2, wherein the ratio of inorganic binder to organic binder is from about 2:1 to 10:

1.

4. 4. The material of claim 3, wherein the ratio of inorganic binder to organic binder is about 3:1 to 8:

1.

5. 10. The material of any one of the preceding claims, wherein the polyhalite composition comprises polyhalite or polyhalite in combination with potassium salt(s).

6. The material of claim 5 , wherein the polyhalite composition comprises a polyhalite.

7. 6. The material of claim 5, wherein the polyhalite composition comprises polyhalite in combination with potassium salt(s).

8. 8. The material of claim 7, wherein the polyhalite composition comprises 8.0% (weight to weight) (w / w) to 98.0% (w / w) polyhalite in combination with 92.0% (w / w) to 2.0% (w / w) potassium salt(s).

9. 9. The material of claim 8, wherein the polyhalite composition comprises 30.0% (w / w) to 80.0% (w / w) polyhalite in combination with 70.0% (w / w) to 20.0% (w / w) potassium salt(s).

10. 10. The material of claim 9, wherein the polyhalite composition comprises 50.0% (w / w) to 80.0% (w / w) polyhalite in combination with 50.0% (w / w) to 20.0% (w / w) potassium salt(s).

11. 11. The material of claim 10, wherein the polyhalite composition comprises 50.0% (w / w) to 70.0% (w / w) polyhalite in combination with 50.0% (w / w) to 30.0% (w / w) potassium salt(s).

12. 12. The material of claim 11, wherein the polyhalite composition comprises 60.0% (w / w) to 70.0% (w / w) polyhalite in combination with 40.0% (w / w) to 30.0% (w / w) potassium salt(s).

13. 13. The material of claim 12, wherein the polyhalite composition comprises about 65.0% (w / w) polyhalite in combination with 35.0% (w / w) potassium salt(s).

14. 14. The material of any one of claims 7 to 13, wherein the potassium salt(s) is selected from potassium chloride, potassium nitrate, potassium sulfate, or a combination thereof.

15. 15. The material of claim 14, wherein the potassium salt is potassium chloride.

16. 10. The material of any one of the preceding claims, wherein the organic binder is native starch, modified starch, pregel starch, corn, potato, manioc, tapioca, rice starch, or any combination thereof, hydrogel, carboxymethylcellulose, magnesium lignosulfonate, sodium lignosulfonate, calcium lignosulfonate, and chitosan, or any combination thereof.

17. 17. The material of claim 16, wherein the organic binder is carboxymethyl cellulose.

18. 18. The material of claim 17, wherein the carboxymethyl cellulose has a weight of from about 90,000 to about 750,000 (and inclusive).

19. 10. The material of any one of the preceding claims, wherein the inorganic binder is selected from gypsum, anhydrite, Na-bentonite, magnesium oxide calcined gypsum, simple superphosphate, magnesium phosphate, aluminum silicate, sodium silicate, potassium silicate, kaolin, mica, syngenite, other forms of polyhalite (including calcined polyhalite, hydrated polyhalite), magnesium sulfate, or combinations thereof.

20. 10. The material of any one of the preceding claims, wherein the inorganic binder is selected from gypsum alpha-hemihydrate or beta-hemihydrate, anhydrite, magnesium oxide, simple superphosphate, magnesium phosphate, syngenite, forms of polyhalite (including calcined polyhalite, hydrated polyhalite), magnesium sulfate (as anhydrous and in monohydrate form) or combinations thereof.

21. 21. The material of claim 20, wherein the inorganic binder is alpha-hemihydrate gypsum.

22. 10. The material of any one of the preceding claims, further comprising boron, colemanite, ulexite, or any combination thereof, and / or zinc oxide or zinc sulfate.

23. 23. The material of claim 22, wherein the boron is present in an amount of 0.1% (w / w) to 1.0% (w / w).

24. 24. The material of claim 23, wherein boron is present in an amount of 0.2% (w / w) to 0.8% (w / w).

25. 25. The material of claim 24, wherein boron is present in an amount of 0.3% (w / w) to 0.5% (w / w).

26. 23. The material of claim 22, wherein zinc is present in an amount of 0.1% (w / w) to 1.0% (w / w).

27. 27. The material of claim 26, wherein zinc is present in an amount preferably between 0.1% (w / w) and 0.5% (w / w).

28. 23. The material of claim 22, wherein zinc is present in an amount of, and even more preferably, from 0.1% (w / w) to 0.3% (w / w).

29. 10. The material of any one of the preceding claims, wherein the granules have a particle size range of 1.0 mm to 6.0 mm.

30. 30. The material of claim 29, wherein the granules have a particle size range of 2.5 mm to 4.0 mm.

31. 31. The material of claim 30, wherein the granules have a particle size range of 2.7 mm to 3.1 mm.

32. 10. The material according to any one of the preceding claims, wherein the granules have an average particle size of 1 mm to 1.9 mm.

33. 33. The material of claim 32, wherein the granules have an average particle size of 2 mm to 2.4 mm.

34. 34. The material of claim 33, wherein the granules have an average particle size of 2.5 mm to 3.5 mm.

35. 35. The material of claim 34, wherein the granules have an average particle size of 2.6 mm to 3.1 mm.

36. 36. The material of claim 35, wherein the granules have an average particle size of 2.70 mm to 2.80 mm.

37. 10. The material of any one of the preceding claims, wherein the granules have a crushing strength of about 2 kgf to about 6 kgf.

38. 38. The material of claim 37, wherein the granules have a crush strength of about 2.5 kgf to about 5 kgf.

39. 39. The material of claim 38, wherein the granules have a crush strength of about 3.0 kgf to about 4 kgf.

40. 37. The material of any one of claims 1 to 36, wherein the granules have a crushing strength of above about 5 kgf.

41. 1. A process for the preparation of polyhalite granules, the process comprising: (a) (i) a polyhalite composition; (ii) 0.2% (w / w) to 2.0% (w / w) of an organic binder; (iii) 0.5% (w / w) to 6.0% (w / w) inorganic binder, wherein the ratio of inorganic binder to organic binder is greater than 1:1; and (iv) 0% (w / w) to 14% (w / w) water to obtain a polyhalite mixture; and (b) granulating the polyhalite mixture to produce polyhalite granules. A process that includes the steps of:

42. 42. The process of claim 41, wherein the polyhalite mixture is added to a granulator to produce polyhalite granules.

43. 43. The process of claim 41 or 42, wherein the ratio of inorganic binder to organic binder is greater than 1:1 to about 10:

1.

44. 44. The process of claim 43, wherein the ratio of inorganic binder to organic binder is from about 2:1 to 10:

1.

45. 45. The process of claim 44, wherein the ratio of inorganic binder to organic binder is from about 3:1 to 8:

1.

46. 46. ​​The process of any one of claims 41 to 45, wherein the polyhalite composition comprises polyhalite or polyhalite in combination with potassium salt(s).

47. 47. The process of claim 46, wherein the polyhalite composition comprises a polyhalite.

48. 47. The process of claim 46, wherein the polyhalite composition comprises polyhalite in combination with potassium salt(s).

49. 49. The process of claim 48, wherein the polyhalite composition comprises 8.0% (weight to weight) (w / w) to 98.0% (w / w) polyhalite in combination with 92.0% (w / w) to 2.0% (w / w) potassium salt(s).

50. 50. The process of claim 49, wherein the polyhalite composition comprises 30.0% (w / w) to 80.0% (w / w) polyhalite in combination with 70.0% (w / w) to 20.0% (w / w) potassium salt(s).

51. 51. The process of claim 50, wherein the polyhalite composition comprises 50.0% (w / w) to 80.0% (w / w) polyhalite in combination with 50.0% (w / w) to 20.0% (w / w) potassium salt(s).

52. 52. The process of claim 51 , wherein the polyhalite composition comprises 50.0% (w / w) to 70.0% (w / w) polyhalite in combination with 50.0% (w / w) to 30.0% (w / w) potassium salt(s).

53. 53. The process of claim 52, wherein the polyhalite composition comprises 60.0% (w / w) to 70.0% (w / w) polyhalite in combination with 40.0% (w / w) to 30.0% (w / w) potassium salt(s).

54. 54. The process of claim 53, wherein the polyhalite composition comprises about 65.0% (w / w) polyhalite in combination with 35.0% (w / w) potassium salt(s).

55. 55. The process of any one of claims 48 to 54, wherein the potassium salt(s) are selected from potassium chloride, potassium nitrate, potassium sulfate, or combinations thereof.

56. 56. The process of claim 55, wherein the potassium salt is potassium chloride.

57. 57. The process of any one of claims 41 to 56, wherein the organic binder is native starch, modified starch, pregel starch, corn, potato, manioc, tapioca, rice starch, or any combination thereof, hydrogel, carboxymethyl cellulose, magnesium lignosulfonate, sodium lignosulfonate, calcium lignosulfonate, and chitosan, or any combination thereof.

58. 58. The process of claim 57, wherein the organic binder is carboxymethyl cellulose.

59. 59. The process of claim 58, wherein the carboxymethyl cellulose has a weight of from about 90,000 to about 750,000 (and inclusive).

60. 60. The process of any one of claims 41 to 59, wherein the inorganic binder is selected from gypsum, anhydrite, Na-bentonite, magnesium oxide calcined gypsum, simple superphosphate, magnesium phosphate, aluminum silicate, sodium silicate, potassium silicate, kaolin, mica, syngenite, other forms of polyhalite (including calcined polyhalite, hydrated polyhalite), magnesium sulfate, or combinations thereof.

61. 60. The process of any one of claims 41 to 59, wherein the inorganic binder is selected from gypsum alpha-hemihydrate or beta-hemihydrate, anhydrite, magnesium oxide, simple superphosphate, magnesium phosphate, syngenite, forms of polyhalite (including calcined polyhalite, hydrated polyhalite), magnesium sulfate (as anhydrous and in monohydrate form), or combinations thereof.

62. 62. The process of claim 61, wherein the inorganic binder is alpha-hemihydrate gypsum.

63. 63. The process of any one of claims 41 to 62, wherein the composition further comprises boron, colemanite, ulexite, or any combination thereof, and / or zinc oxide or zinc sulfate.

64. 64. The process of claim 63, wherein the boron is present in an amount of 0.1% (w / w) to 1.0% (w / w).

65. 65. The process of claim 64, wherein the boron is present in an amount of 0.2% (w / w) to 0.8% (w / w).

66. 66. The process of claim 65, wherein the boron is present in an amount of 0.3% (w / w) to 0.5% (w / w).

67. 65. The process of claim 64, wherein zinc is present in an amount of 0.1% (w / w) to 1.0% (w / w).

68. 68. The process of claim 67, wherein zinc is present in an amount preferably of 0.1% (w / w) to 0.5% (w / w).

69. 69. The process of claim 68, wherein zinc is present in an amount of, and even more preferably, from 0.1% (w / w) to 0.3% (w / w).

70. 70. The process of any one of claims 41 to 69, wherein the granules have a particle size range of 1.0 mm to 6.0 mm.

71. 71. The process of claim 70, wherein the granules have a particle size range of 2.5 mm to 4.0 mm.

72. 72. The process of claim 71, wherein the granules have a particle size range of 2.7 mm to 3.1 mm.

73. 73. The process of any one of claims 41 to 72, wherein the granules have an average particle size of 1 mm to 1.9 mm.

74. 74. The process of claim 73, wherein the granules have an average particle size of 2 mm to 2.4 mm.

75. 75. The process of claim 74, wherein the granules have an average particle size of 2.5 mm to 3.5 mm.

76. 76. The process of claim 75, wherein the granules have an average particle size of 2.6 mm to 3.1 mm.

77. 77. The process of claim 76, wherein the granules have an average particle size of 2.70 mm to 2.80 mm.

78. 78. The process of any one of claims 41 to 77, wherein the granules have a crushing strength of about 2 kgf to about 6 kgf.

79. 79. The process of claim 78, wherein the granules have a crushing strength of about 2.5 kgf to about 5 kgf.

80. 80. The process of claim 79, wherein the granules have a crushing strength of about 3.0 kgf to about 4 kgf.

81. 81. The process of any one of claims 41 to 80, wherein the granules have a crushing strength above about 5 kgf.

82. 82. The process of any one of claims 41 to 81, having a granulation efficiency of at least 40%, including about 55% and about 70%.

83. 83. The process of any one of claims 41 to 82, wherein the polyhalite granules produced in step (b) are dried in a drying apparatus.

84. A granule comprising polyhalite or polyhalite in combination with potassium salt(s), having a crushing strength of 2.0 kgf to 6.0 kgf and a final moisture content of 0.25 to 0.50% w / w.

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