Polyhalite particles

Abstract

The present invention provides a particulate material comprising a polyhalite composition; 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, where the ratio of inorganic binder to organic binder is greater than 1: 1, as well as a method of making the material. The invention further provides a particle comprising a polyhalite or a combination of a polyhalite and a potassium salt having a compressive 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] The present invention relates to polyhalite particles and a method for manufacturing the same. The polyhalite particles comprise polyhalite and / or a combination of polyhalite and potash (e.g., from a potash source), an organic binder, and an inorganic binder. Background Art

[0002] Granulation of polyhalite is a method that has good performance when granulating without using a binder or using an organic binder. However, the high water absorption of polyhalite particles poses challenges, which can significantly reduce the compressive strength of the granular product, even if there are no fines in the original granular product, resulting in a high level of degradation and dust generation. The above-mentioned drawbacks particularly occur when using starch as a binder, because the hygroscopicity of starch causes the particles to degrade under humid conditions. Therefore, the limitation of polyhalite particles with starch as a binder is that the physical integrity of the particles is poor during long-term transportation, handling, and storage. Starch only provides physical interaction and does not provide chemical interaction, and this physical interaction deteriorates over time and due to the action of microorganisms.

[0003] There is a need for polyhalite particles that can improve the above problems. Summary of the Invention

[0004] According to a first aspect of the present invention, there is provided a granular material comprising:

[0005] · A polyhalite composition;

[0006] · 0.2% (w / w) to 2.0% (w / w) of an organic binder; and

[0007] · 0.5% (w / w) to 6.0% (w / w) of an inorganic binder, wherein

[0008] The ratio of the inorganic binder to the organic binder is greater than 1:1.

[0009] The ratio of the inorganic to the organic binder can be greater than 1:1 to about 10:1, typically about 2:1 to 10:1, preferably about 3:1 to 8:1. In other words, there is more inorganic binder than organic binder.

[0010] The polyhalite composition may comprise polyhalite, or a combination of polyhalite and potash. The polyhalite composition may consist essentially of polyhalite. The polyhalite composition may consist of polyhalite.

[0011] The polyhalite composition may comprise a combination of 8.0% (by weight) (w / w) to 98.0% (w / w) polyhalite and 92.0% (w / w) to 2.0% (w / w) potash; a combination of 30.0% (w / w) to 80.0% (w / w) polyhalite and 70.0% (w / w) to 20.0% (w / w) potash, preferably a combination of 50.0% (w / w) to 80.0% (w / w) polyhalite and 50.0% (w / w) to 20.0% (w / w) potash, more preferably a combination of 50.0% (w / w) to 70.0% (w / w) polyhalite and 50.0% (w / w) to 30.0% (w / w) potash, even more preferably a combination of 60.0% (w / w) to 70.0% (w / w) polyhalite and 40.0% (w / w) to 30.0% (w / w) potash, typically a combination of about 65.0% (w / w) polyhalite and 35.0% (w / w) potash.

[0012] The potash may be selected from potassium chloride, potassium nitrate, potassium sulfate or combinations thereof, preferably potassium chloride.

[0013] The organic binder may be natural starch, modified starch, pregelatinized starch (pregelatinized starch is starch that has been pre-cooked and dried to enhance its thickening and water-absorbing capabilities at lower temperatures), corn, potato, tapioca, cassava, rice starch or any combination thereof, hydrogel, carboxymethyl cellulose, magnesium lignosulfonate, sodium lignosulfonate, calcium lignosulfonate and chitosan, or any combination thereof. The starch may be pretreated with sodium hydroxide (NaOH) to facilitate low-temperature gelatinization of the starch and the resulting rheological profile changes.

[0014] In a preferred embodiment of the present invention, the organic binder is carboxymethyl cellulose. The weight of the carboxymethyl cellulose may be from about 90,000 to about 750,000 (including the end values).

[0015] The inorganic binder may be selected from gypsum, anhydrite, sodium bentonite, magnesium oxide plaster of Paris, monocalcium phosphate, magnesium phosphate, aluminum silicate, sodium silicate, potassium silicate, kaolin, mica, potassium sulfate, other forms of polyhalite (including calcined polyhalite, hydrated polyhalite), magnesium sulfate or combinations thereof.

[0016] Preferred inorganic binders are the α - hemihydrate or β - hemihydrate of gypsum, anhydrite, magnesium oxide, monocalcium phosphate, magnesium phosphate, potassium sulfate, various forms of polyhalite (including calcined polyhalite, hydrated polyhalite), magnesium sulfate (in anhydrous and monohydrate forms) or combinations thereof, preferably α - hemihydrate gypsum.

[0017] The granular material (particles) may further comprise boron, such as borax, colemanite, ulexite or any combination thereof, and / or zinc oxide or zinc sulfate.

[0018] 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).

[0019] 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).

[0020] The particle size range of the kainite particles may generally be from 1.0 mm to 6.0 mm, preferably from 2.5 mm to 4.0 mm, and even more preferably from 2.7 mm to 3.1 mm.

[0021] The average particle size of the kainite particles 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.

[0022] The kainite particles according to the present invention may have a compressive 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 kainite particles have a compressive strength higher than about 5 kgf.

[0023] Without being bound by theory, the applicant believes that the above parameters result in an improved product with improved wear resistance and improved coating properties (i.e., the ability to be coated). This is thought to be due to the particles presenting a smoother spherical shape, which is easier to coat and less likely to be worn. In this regard, it is preferred that the inorganic part in the binder is greater than the organic part.

[0024] According to a second aspect of the present invention, there is provided a method for preparing the kainite particles according to the first aspect of the present invention, the method comprising the following steps:

[0025] (a) Mixing

[0026] (i) A kainite composition;

[0027] (ii) An organic binder of 0.2% (w / w) to 2.0% (w / w);

[0028] (iii) An inorganic binder of 0.5% (w / w) to 6.0% (w / w), wherein the ratio of the inorganic binder to the organic binder is greater than 1:1; and

[0029] (iv) Water of 0% (w / w) to 14% (w / w),

[0030] to obtain a kainite mixture; and

[0031] (b) Granulate the kainite mixture to produce kainite particles.

[0032] The kainite composition can be added to a granulator to produce kainite particles.

[0033] The ratio of inorganic to organic binder can be greater than 1:1 to about 10:1, typically about 2:1 to 10:1, preferably about 3:1 to 8:1. In other words, there is more inorganic binder than organic binder.

[0034] The kainite composition can comprise kainite, or a combination of kainite and potash. The kainite composition can consist essentially of kainite. The kainite composition can consist of kainite.

[0035] The kainite composition can comprise a combination of 8.0% (by weight) (w / w) to 98.0% (w / w) kainite and 92.0% (w / w) to 2.0% (w / w) potash; a combination of 30.0% (w / w) to 80.0% (w / w) kainite and 70.0% (w / w) to 20.0% (w / w) potash, preferably a combination of 50.0% (w / w) to 80.0% (w / w) kainite and 50.0% (w / w) to 20.0% (w / w) potash, more preferably a combination of 50.0% (w / w) to 70.0% (w / w) kainite and 50.0% (w / w) to 30.0% (w / w) potash, even more preferably a combination of 60.0% (w / w) to 70.0% (w / w) kainite and 40.0% (w / w) to 30.0% (w / w) potash, typically about 65.0% (w / w) kainite and 35.0% (w / w) potash.

[0036] The potash can be selected from potassium chloride, potassium nitrate, potassium sulfate, or a combination thereof, preferably potassium chloride.

[0037] The organic binder can be natural starch, modified starch, pregelatinized starch (pregelatinized starch is starch that has been precooked and dried to enhance its thickening and water-absorbing capabilities at lower temperatures), corn, potato, tapioca, cassava, rice starch, or any combination thereof, hydrogel, carboxymethyl cellulose, magnesium lignosulfonate, sodium lignosulfonate, calcium lignosulfonate, and chitosan, or any combination thereof. The starch can be pretreated with sodium hydroxide (NaOH) to promote low-temperature gelatinization of the starch and the resulting change in rheological profile.

[0038] In a preferred embodiment of the present invention, the organic binder is carboxymethyl cellulose. The weight of the carboxymethyl cellulose can be from about 90,000 to about 750,000 (and including the end values).

[0039] The inorganic binder may be selected from gypsum, anhydrite, sodium bentonite, magnesia plaster, monocalcium phosphate, magnesium phosphate, aluminum silicate, sodium silicate, potassium silicate, kaolin, mica, potassium sulfate, other forms of polyhalite (including calcined polyhalite, hydrated polyhalite), magnesium sulfate or combinations thereof.

[0040] Preferred inorganic binders are the α - hemihydrate or β - hemihydrate of gypsum, anhydrite, magnesia, monocalcium phosphate, magnesium phosphate, potassium sulfate, various forms of polyhalite (including calcined polyhalite, hydrated polyhalite), magnesium sulfate (in anhydrous and monohydrate forms) or combinations thereof, with α - hemihydrate gypsum being preferred.

[0041] The granular material (particles) may also contain boron, such as borax, ulexite, tincalconite or any combination thereof, and / or zinc oxide or zinc sulfate.

[0042] Boron may be present in an amount of from 0.1% (w / w) to 1.0% (w / w), preferably from 0.2% (w / w) to 0.8% (w / w) and even more preferably from 0.3% (w / w) to 0.5% (w / w).

[0043] Zinc may be present in an amount of from 0.1% (w / w) to 1.0% (w / w), preferably from 0.1% (w / w) to 0.5% (w / w) and even more preferably from 0.1% (w / w) to 0.3% (w / w).

[0044] The method according to this aspect of the invention may have a granulation efficiency of at least about 40%, more preferably about 55% and even more preferably about 70%.

[0045] The granulation efficiency is the percentage of particles that reach an acceptable product size at the end of the granulator. For the present invention, particles between 4 and 2 mm are preferably considered.

[0046] The polyhalite particles produced in step (b) may be dried in a drying device.

[0047] According to a third aspect of the present invention, there is provided a particle comprising a combination of polyhalite and a potassium salt, having a compressive strength of 2.0 kgf to 6.0 kgf and a final moisture content of 0.25 to 0.50% w / w. Description of the Drawings

[0048] The present invention will be fully understood from the detailed description given herein, as well as the drawings and results, which are given by way of illustration only and do not limit the intended scope of the invention.

[0049] Figure 1 is a flow chart of the method for preparing polyhalite particles of the present invention;

[0050] Figure 2Are the kainite + potassium chloride (65:35 w / w) particles produced in Experiments 3, 14, and 14';

[0051] Figure 3 Are the kainite + potassium chloride (65:35 w / w) particles produced in Experiments 5, 15, and 16;

[0052] Figure 4 Are the kainite + potassium chloride (65:35 w / w) particles produced in Experiments 19 and 20;

[0053] Figure 5 Are the kainite + potassium chloride (65:35 w / w) particles produced in Experiments 4, 21, 22, 23, 24, 25, 26, and 29;

[0054] Figure 6 Are the kainite + potassium chloride (65:35 w / w) particles produced in Experiments 17 and 18;

[0055] Figure 7 Are the kainite + potassium chloride (65:35 w / w) particles produced in Experiment 32;

[0056] Figure 8 Is a graph showing the granulation efficiency (%) and compressive strength (kgf) of Experiments 1 to 32;

[0057] Figure 9 Shows the processing conditions of further experiments;

[0058] Figure 10 Shows the characteristics of kainite particles produced in further Experiments 03, 04, and 05. Detailed Description

[0059] The present invention relates to the granulation of kainite (kainite is a hydrated evaporite mineral that contains sulfates of potassium, calcium, and magnesium, with the chemical formula K2Ca2Mg(SO4)4·2H2O) or a combination of kainite and potash salts (chlorides of potash), preferably potassium chloride, using a combination of organic and inorganic materials as binders to improve granulation and the quality of the final product. The organic and inorganic additives or binders can be in solid or liquid phase. The liquid phase can be a suspension or a dilution material in water. Starch can also be pretreated in a sodium hydroxide solution. Granulation can be carried out in a drum, a pan, a fluidized bed, a high-shear mixer, an extruder, a paddle mixer, a 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 (degrees Celsius).

[0060] The present invention can reduce the generation of dust and minimize the reduction of compressive strength over time. It can also produce particles with a better shape, such as more rounded particles. The combination of inorganic and organic binders can reduce the water absorption of the final product and / or its kinetics. In addition, this can also reduce the dependence on high doses of other additives / chemicals (such as coatings), which only help to prevent the deterioration of the particles after they are made.

[0061] The organic binder aids the granulation process by binding polyhalite and sylvite during the aggregation process and can be selected from natural starches, modified starches, pregelatinized starches (pregelatinized starches are starches that have been pre-cooked and dried to enhance their thickening and water absorption capabilities at lower temperatures), corn, potato, tapioca, cassava, rice starch or any combination thereof, hydrogels, carboxymethyl cellulose, magnesium lignosulfonate, sodium lignosulfonate, calcium lignosulfonate and chitosan, or any combination thereof. The starch can be pretreated with sodium hydroxide (NaOH) to promote low-temperature gelatinization of the starch and the resulting rheological profile changes. In a preferred embodiment of the present invention, the organic binder is carboxymethyl cellulose. The weight of the carboxymethyl cellulose is from about 90,000 to about 750,000 (and including the end values).

[0062] According to the method of the present invention, it has been found that the combination of an organic binder and an inorganic binder not only improves the granulation process but also improves the compressive strength. The surprising finding is that gypsum, a soft sulfate mineral composed of calcium sulfate dihydrate with the chemical formula Ca2SO4·2H2O, can improve the granulation efficiency of the process and produce a high compressive strength. Without wishing to be bound by theory, it is believed that the increase in compressive strength is due to the formation of crystal bridges through the reaction or hydration of the mineral, which surprisingly occurs in the absence of an acid for the reaction to take place. Due to its crystal structure, α-hemihydrate gypsum is preferred. The β-hemihydrate consists of fine aggregates. In contrast, the α-hemihydrate consists of coarser particles that are well-defined crystals. Other inorganic binders expected to act in the same way are anhydrite, magnesium oxide, monocalcium phosphate, magnesium phosphate, langbeinite, polyhalite forms (including calcined polyhalite, hydrated polyhalite), magnesium sulfate (anhydrous and monohydrate forms) or combinations thereof.

[0063] The proportion of the binder contained in the particles has a surprising effect on the particles. If the organic and inorganic binders are added in the correct proportions during granulation, the best effects of each binder can be achieved. This means achieving a higher compressive strength (using the organic matter), compacted and smooth particles, and easier granulation (using the inorganic matter). The organic:inorganic ratio will depend on the inorganic binder selected. The amount of the organic binder is 1.5% w / w or less, while the addition amount of the inorganic binder can reach 6% w / w. A more suitable inorganic:organic binder ratio seems to be between 3:1 and 8:1.

[0064] Granulation efficiency is the percentage of particles at the end of the granulator that reach a size considered to be an acceptable product. For the present invention, particles between preferably 4 and 2 mm are considered.

[0065] The carnallite particles according to the present invention may have a compressive strength of from about 2 kgf to about 6 kgf, more preferably from about 2.5 kgf to about 5 kgf, and most preferably from about 3.0 kgf to about 4 kgf. In one embodiment of the present invention, the carnallite particles have a compressive strength higher than about 5 kgf.

[0066] The kilogram-force (kgf) is a metric unit of force equal to the force exerted in a gravitational field by a mass of 1 kilogram. Thus, one kilogram-force is equal to 9.80665 N. 2 The magnitude of the force exerted by a mass of 1 kilogram in a gravitational field. Thus, one kilogram-force is equal to 9.80665 N.

[0067] Compressive strength is a measure of the ability of a particle to resist deformation or breakage under pressure. Compressive strength helps to estimate the expected handling and storage characteristics of particulate materials and to determine the pressure limits applied during bagged and bulk storage. A preferred procedure dictates that pressure is applied to more than 25 (usually 30) particles between 2.36 mm and 2.79 mm until breakage is observed. The force applied to break the particles is the compressive strength (Particle Compressive Strength - IFDC Methodology S-115).

[0068] The particles may also contain nutrients, including macronutrients / micronutrients selected from:

[0069] · Potassium sulfate, potassium chloride, kainite, potassium nitrate, etc.,

[0070] · Sulfur (elemental sulfur, ammonium sulfate) and

[0071] · Urea

[0072] Optional additional components of the particles may be one or more of the following:

[0073] · Boron (borax, colemanite, ulexite),

[0074] · Zinc (zinc oxide, zinc sulfate) and

[0075] · Magnesium (magnesium oxide, kieserite, magnesite).

[0076] Examples

[0077] Figure 1 Illustrates the graphical procedure for each experiment. Figure 1A method (10) for preparing polyhalite particles according to the present invention is shown, wherein a mixture of polyhalite (2), a mixture of polyhalite and potash (4), and an organic and inorganic binder (6) with water (8) is added to an Eirich (RTM) high-intensity mixer (12) and then transferred (14) to a disk granulator (16). It should be understood that different granulation equipment can be used, such as a drum granulator, a disk granulator, an Eirich (RTM) high-shear machine, a spheronizer, a fluidized bed, or any other type of equipment or combination capable of producing particles. The wet particles are then transferred (18) to a dryer (20).

[0078] The drying conditions should be around 100 °C, but it can also be carried out at a lower temperature (e.g., 70 - 95 °C), but should not be higher than about 120 °C to avoid degradation or caramelization of the organic materials.

[0079] After drying, polyhalite particles (20) according to the present invention are prepared. The granulation efficiency can be higher than 70 - 80%, and the compressive strength is higher than 4 kgf (39.23 N).

[0080] 32 experiments were carried out by adding different binders and combinations, as shown below, see Figure 8 :

[0081] All experiments used water at 90 degrees Celsius.

[0082] · Experiment 1, 1' and 12 - without binder

[0083] No binder was used to produce polyhalite and potassium chloride particles. Polyhalite and potassium chloride (65:35 w / w) and water at 90 °C were used during the granulation process to produce polyhalite and potassium chloride particles. The compressive strength of the particles in all three experiments was 1.7 kgf (16.67 N), and the granulation efficiency varied with the process conditions and the water added during the granulation process.

[0084]

[0085] · Experiment 3, 14 and 14' - pre-gelatinized corn starch

[0086] Polyhalite, potassium chloride, pre-gelatinized corn starch, and water at 90 °C were used during the granulation process to produce polyhalite particles. The compressive strength of the particles was 3.7 kgf (36.28 N), and this compressive strength was achieved when 7 wt% of water was added (Experiment 14'). Experiments 3 and 14 did not produce particles with an ideal particle size distribution (9% and 7.5% of water were added respectively), and the particle surface had roughness.

[0087] The granular polyhalite and potassium chloride products are as Figure 2 shown.

[0088]

[0089] · Experiment 5, 15 and 16 - α-HH gypsum

[0090] For Experiments 5, 15, and 16, kieserite, potassium chloride, α-HH gypsum, and water with contents of 7.2%, 7.0%, and 7.5% respectively were used in the granulation process to produce kieserite and potassium chloride granules. The compressive strength was very low - approximately 0.6 - 0.7 kgf (5.88 - 6.86 N). The granules were smooth and easy to granulate. It was observed that α-HH gypsum had less hygroscopic behavior. The granular kieserite product is as Figure 3 shown.

[0091]

[0092] · Experiment 19 and 20 - bentonite and starch

[0093] Previous experience has shown that bentonite helps with granulation but not with compressive strength. Starch was added to combine with bentonite to increase the compressive strength. Kieserite, potassium chloride, bentonite, starch, and water were used in the granulation process to produce kieserite and potassium chloride granules. The use of different organic and inorganic binders had a positive impact on the hardness of the product, granulation behavior, and physical properties of the final product.

[0094]

[0095] The resulting granules did not reach the optimal liquid phase conditions. The granulation efficiency can be improved by changing the process conditions. The compressive strength of Experiment 19 was the highest, at 4.5 kgf (44.13 N).

[0096] The granular kieserite product is as Figure 4 shown.

[0097] · Experiment 4, 21, 22, 23, 24, 25, 26 and 29 - ArrMaz Adhesive TM

[0098] Kieserite and potassium chloride, an ArrMaz binder TM (an organic binder containing carboxymethyl cellulose), and water were used in the granulation process to produce kieserite and potassium chloride granules. (" TM " is regarded as the designation of a registered trademark (RTM)). Due to the action of the binder, granulation was successful. A slight change in the granulation temperature seemed to affect the granulation efficiency and product behavior, changing from very difficult to granulate (only forming fine powder) to very easy and rapid granulation, and after adding a small amount of water, a large dry ball was formed within a few seconds. The granulation curve looked small and it was easy to transition from fine powder to coarse granules. The formed granules did not have a smooth surface, but nevertheless, the binder had a positive impact on the compressive strength of the final product.

[0099]

[0100] Granular polyhalite products are as Figure 5 shown.

[0101] · Experiment 17, 18 and 32 - α-HH gypsum and starch

[0102] In the granulation process, polyhalite, potassium chloride, α-HH gypsum, starch, and water are used to produce polyhalite and potassium chloride granules. It is easier to granulate, with high compressive strength (3.7, 3.6, and 2.0 kgf (36.28, 35.30; 19.61 N) in Experiments 17, 18, and 32 respectively), and the granulation efficiency is between 39 - 50%. The granules of the produced polyhalite and potassium chloride mixture are rounder and easier to granulate than using pre-gelatinized corn starch alone. The polyhalite and potassium chloride granules have good compressive strength (which cannot be achieved by using α-HH gypsum alone). Granular polyhalite products are as Figure 6 and Figure 7 shown.

[0103] The use of different organic and inorganic binders affects the product hardness, granulation behavior, and physical properties of the final product.

[0104]

[0105] · Experiment 31 - α-HH gypsum and ArrMAz adhesive TM

[0106] In the granulation process, polyhalite, potassium chloride, α-HH gypsum, ArrMaz binder TM and water are used to produce polyhalite and potassium chloride granules. The ratio of organic:inorganic binders and process conditions can be controlled to achieve the highest compressive strength, the best physical properties, and higher granulation efficiency. Preliminary results indicate that the organic:inorganic ratio will depend on the selected inorganic binder. The amount of organic binder is 1.5% w / w or less, while the addition amount of inorganic binder can reach 6% w / w. A more suitable inorganic:organic binder ratio seems to be between 3:1 and 8:1.

[0107]

[0108] The use of different organic and inorganic binders affects the product hardness, granulation behavior, and physical properties of the final product.

[0109] Based on the above experiments, further experiments were conducted by changing the ratio of organic and inorganic binders to understand the granulation behavior, compressive strength, liquid phase, product properties, and granulation efficiency. In this example, α-HH gypsum and ArrMaz binder TMCombinations. Continuing with the Central Composite Design (CCD) having 2 variables (organic:inorganic binder ratio and water addition), there are 2 replicates at the central point. The granulation time used for the experiments was fixed at 7 minutes (4 minutes in a high-shear mixer and 3 minutes in a pan granulator), the ratio of polyhalite and potassium chloride was the same for all CCDs (polyhalite:potassium chloride - 65:35), and the mixing, liquid addition, and compaction times during granulation were also fixed. The processing conditions for further experiments are as Figure 9 shown.

[0110] The results of the polyhalite and potassium chloride granule products are as Figure 10 shown. Unfortunately, all CCD experiments except experiments 3, 4, and 5 resulted in fines or coarse particles, and the properties of the final product could not be determined or a statistical evaluation could not be performed. The granular polyhalite and potassium chloride products are shown in Figure 11.

[0111]

[0112] Based on the results, the ratio of the binder contained in the granules has a surprising effect on the granules. If the organic and inorganic binders are added in the correct ratio during granulation, the best effects of each binder can be achieved. This means achieving higher compressive strength (using organic matter), compacted and smooth granules, and easier granulation (using inorganic matter).

[0113] · Experiment 32 - 35 - kainite with inorganic and organic binders

[0114] The combination of polyhalite (100%) with organic / inorganic binder and water was used in the granulation process to produce polyhalite granules. The ratio of organic:inorganic binder and the process conditions can be controlled to achieve the highest compressive strength, optimal physical properties, and higher granulation efficiency. The preliminary results indicate that the organic:inorganic ratio will depend on the selected inorganic binder. The amount of organic binder used is 1.5% w / w or less, while the addition amount of inorganic binder can reach 6% w / w. A more suitable ratio is that the ratio of inorganic binder to organic binder is greater than 1:1.

[0115]

Claims

1. A granular material, comprising: i. A polyhalite composition; ii. 0.2% (w / w) to 2.0% (w / w) organic binder; and iii. 0.5% (w / w) to 6.0% (w / w) inorganic binder; wherein the ratio of the inorganic binder to the organic binder is greater than 1:

1.

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

1.

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

1.

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

1.

5. The material according to any one of the preceding claims, wherein the polyhalite composition comprises polyhalite, or a combination of polyhalite and sylvite.

6. The material according to claim 5, wherein the polyhalite composition comprises polyhalite.

7. The material according to claim 5, wherein the polyhalite composition comprises a combination of polyhalite and sylvite.

8. The material according to claim 7, wherein the polyhalite composition comprises a combination of 8.0% (by weight) (w / w) to 98.0% (w / w) polyhalite and 92.0% (w / w) to 2.0% (w / w) sylvite.

9. The material according to claim 8, wherein the polyhalite composition comprises a combination of 30.0% (w / w) to 80.0% (w / w) polyhalite and 70.0% (w / w) to 20.0% (w / w) sylvite.

10. The material according to claim 9, wherein the polyhalite composition comprises a combination of 50.0% (w / w) to 80.0% (w / w) polyhalite and 50.0% (w / w) to 20.0% (w / w) sylvite.

11. The material according to claim 10, wherein the polyhalite composition comprises a combination of 50.0% (w / w) to 70.0% (w / w) polyhalite and 50.0% (w / w) to 30.0% (w / w) sylvite.

12. The material according to claim 11, wherein the polyhalite composition comprises a combination of 60.0% (w / w) to 70.0% (w / w) polyhalite and 40.0% (w / w) to 30.0% (w / w) sylvite.

13. The material according to claim 12, wherein the polyhalite composition comprises a combination of about 65.0% (w / w) polyhalite and 35.0% (w / w) sylvite.

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

15. The material according to claim 14, wherein the sylvite is potassium chloride.

16. The material according to any one of the preceding claims, wherein the organic binder is natural starch, modified starch, pregelatinized starch, corn, potato, tapioca, cassava, rice starch, or any combination thereof, hydrogel, carboxymethyl cellulose, magnesium lignosulfonate, sodium lignosulfonate, calcium lignosulfonate, and chitosan, or any combination thereof.

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

18. The material according to claim 17, wherein the weight of the carboxymethyl cellulose is from about 90,000 to about 750,000 (and including the end values).

19. The material according to any one of the preceding claims, wherein the inorganic binder is selected from gypsum, anhydrite, sodium-based bentonite, magnesia plaster of Paris, monocalcium phosphate, magnesium phosphate, aluminum silicate, sodium silicate, potassium silicate, kaolin, mica, potassium sulfate, other forms of polyhalite (including calcined polyhalite, hydrated polyhalite), magnesium sulfate or combinations thereof.

20. The material according to any one of the preceding claims, wherein the inorganic binder is selected from the α - hemihydrate or β - hemihydrate of gypsum, anhydrite, magnesia, monocalcium phosphate, magnesium phosphate, potassium sulfate, various forms of polyhalite (including calcined polyhalite, hydrated polyhalite), magnesium sulfate (anhydrous and monohydrate forms) or combinations thereof.

21. The material according to claim 20, wherein the inorganic binder is α - hemihydrate gypsum.

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

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

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

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

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

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

28. The material according to claim 22, wherein the zinc is present in an even more preferred amount of 0.1% (w / w) to 0.3% (w / w).

29. The material according to any one of the preceding claims, wherein the particle size range of the particles is from 1.0 mm to 6.0 mm.

30. The material according to claim 29, wherein the particle size range of the particles is from 2.5 mm to 4.0 mm.

31. The material according to claim 30, wherein the particle size range of the particles is from 2.7 mm to 3.1 mm.

32. The material according to any one of the preceding claims, wherein the average particle size of the particles is from 1 mm to 1.9 mm.

33. The material according to claim 32, wherein the average particle size of the particles is from 2 mm to 2.4 mm.

34. The material according to claim 33, wherein the average particle size of the particles is from 2.5 mm to 3.5 mm.

35. The material according to claim 34, wherein the average particle size of the particles is from 2.6 mm to 3.1 mm.

36. The material according to claim 35, wherein the average particle size of the particles is from 2.70 mm to 2.80 mm.

37. The material according to any one of the preceding claims, wherein the particles have a compressive strength of from about 2 kgf to about 6 kgf.

38. The material according to claim 37, wherein the particles have a compressive strength of from about 2.5 kgf to about 5 kgf.

39. The material according to claim 38, wherein the particles have a compressive strength of from about 3.0 kgf to about 4 kgf.

40. The material according to any one of claims 1 to 36, wherein the particles have a compressive strength higher than about 5 kgf.

41. A method for preparing polyhalite particles, the method comprising the steps of: (a) Mixing (i) a polyhalite composition; (ii) 0.2% (w / w) to 2.0% (w / w) organic binder; (iii) 0.5% (w / w) to 6.0% (w / w) inorganic binder, wherein the ratio of the inorganic binder to the 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 particles.

42. The method according to claim 41, wherein the polyhalite mixture is added to a granulator to produce the polyhalite particles.

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

1.

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

1.

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

1.

46. The method according to any one of claims 41 to 45, wherein the polyhalite composition comprises polyhalite, or a combination of polyhalite and potash.

47. The method according to claim 46, wherein the polyhalite composition comprises polyhalite.

48. The method according to claim 46, wherein the polyhalite composition comprises a combination of polyhalite and potash.

49. The method according to claim 48, wherein the polyhalite composition comprises a combination of 8.0% (by weight) (w / w) to 98.0% (w / w) polyhalite and 92.0% (w / w) to 2.0% (w / w) potash.

50. The method according to claim 49, wherein the polyhalite composition comprises a combination of 30.0% (w / w) to 80.0% (w / w) polyhalite and 70.0% (w / w) to 20.0% (w / w) potash.

51. The method according to claim 50, wherein the polyhalite composition comprises a combination of 50.0% (w / w) to 80.0% (w / w) polyhalite and 50.0% (w / w) to 20.0% (w / w) potash.

52. The method according to claim 51, wherein the kainite composition comprises a combination of 50.0% (w / w) to 70.0% (w / w) kainite and 50.0% (w / w) to 30.0% (w / w) potash salts.

53. The method according to claim 52, wherein the kainite composition comprises a combination of 60.0% (w / w) to 70.0% (w / w) kainite and 40.0% (w / w) to 30.0% (w / w) potash salts.

54. The method according to claim 53, wherein the kainite composition comprises a combination of approximately 65.0% (w / w) kainite and 35.0% (w / w) potash salts.

55. The method according to any one of claims 48 to 54, wherein the potash salts are selected from potassium chloride, potassium nitrate, potassium sulfate, or a combination thereof.

56. The method according to claim 55, wherein the potash salt is potassium chloride.

57. The method according to any one of claims 41 to 56, wherein the organic binder is natural starch, modified starch, pregelatinized starch, corn, potato, cassava, tapioca, rice starch, or any combination thereof, hydrogel, carboxymethyl cellulose, magnesium lignosulfonate, sodium lignosulfonate, calcium lignosulfonate, and chitosan, or any combination thereof.

58. The method according to claim 57, wherein the organic binder is carboxymethyl cellulose.

59. The method according to claim 58, wherein the weight of the carboxymethyl cellulose is from about 90,000 to about 750,000 (including the end values).

60. The method according to any one of claims 41 to 59, wherein the inorganic binder is selected from gypsum, anhydrite, sodium-based bentonite, magnesia plaster of Paris, monocalcium phosphate, magnesium phosphate, aluminum silicate, sodium silicate, potassium silicate, kaolin, mica, potassium sulfate, other forms of kainite (including calcined kainite, hydrated kainite), magnesium sulfate, or a combination thereof.

61. The method according to any one of claims 41 to 59, wherein the inorganic binder is selected from the α - hemihydrate or β - hemihydrate of gypsum, anhydrite, magnesia, monocalcium phosphate, magnesium phosphate, potassium sulfate, various forms of kainite (including calcined kainite, hydrated kainite), magnesium sulfate (anhydrous and monohydrate forms), or a combination thereof.

62. The method according to claim 61, wherein the inorganic binder is α - hemihydrate gypsum.

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

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

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

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

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

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

69. The method according to claim 68, wherein the zinc is present in an even more preferred amount of 0.1% (w / w) to 0.3% (w / w).

70. The method according to any one of claims 41 to 69, wherein the particle size range of the particles is from 1.0 mm to 6.0 mm.

71. The method according to claim 70, wherein the particle size range of the particles is from 2.5 mm to 4.0 mm.

72. The method according to claim 71, wherein the particle size range of the particles is from 2.7 mm to 3.1 mm.

73. The method according to any one of claims 41 to 72, wherein the particles have an average particle diameter of 1 mm to 1.9 mm.

74. The method according to claim 73, wherein the average particle diameter of the particles is 2 mm to 2.4 mm.

75. The method according to claim 74, wherein the average particle diameter of the particles is 2.5 mm to 3.5 mm.

76. The method according to claim 75, wherein the average particle diameter of the particles is 2.6 mm to 3.1 mm.

77. The method according to claim 76, wherein the average particle diameter of the particles is 2.70 mm to 2.80 mm.

78. The method according to any one of claims 41 to 77, wherein the particles have a compressive strength of about 2 kgf to about 6 kgf.

79. The method according to claim 78, wherein the particles have a compressive strength of about 2.5 kgf to about 5 kgf.

80. The method according to claim 79, wherein the particles have a compressive strength of about 3.0 kgf to about 4 kgf.

81. The method according to any one of claims 41 to 80, wherein the particles have a compressive strength higher than about 5 kgf.

82. The method according to any one of claims 41 to 81, which has a granulation efficiency of at least 40%, including about 55% and about 70%.

83. The method according to any one of claims 41 to 82, wherein the carnallite particles produced in step (b) are dried in a drying device.

84. A particle comprising carnallite or a combination of carnallite and potash, having a compressive 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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