Sulfate suspension

Abstract

Provided herein is a suspension comprising at least one sulfate at a concentration of at least 50% w / w; and at least one suspending agent.

Description

Field of the Invention

[0001] The present invention relates to the field of fertilizers, in particular to the production of sulfate suspensions acting as fertilizers. Background of the Invention

[0003] To grow properly, plants require nutrients that can normally be found in the soil (nitrogen, phosphorus, potassium, calcium, zinc, magnesium, iron, manganese, etc.) Fertilizers are sometimes needed to enhance or achieve a desired stage of plant growth.

[0004] Plant growth is met through two main modes. The traditional mode is to provide nutrients through additives. The second mode is that some fertilizers enhance the effectiveness of the soil by changing the water retention and aeration of the soil. Fertilizers usually provide three major macronutrients, three minor macronutrients and micronutrients in varying proportions. The major macronutrients are:

[0005] Nitrogen (N): leaf growth;

[0006] Phosphorus (P): Development of roots, flowers, seeds, and fruits;

[0007] Potassium (K): vigorous stem growth, movement of water in the plant, promotion of flowering and fruiting;

[0008] Secondary macronutrients are: calcium (Ca), magnesium (Mg), and sulfur (S);

[0009] Micronutrients are: copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn), boron (B), and occasionally significant amounts of silicon (Si), cobalt (Co) and vanadium (V) as well as rare mineral catalysts.

[0010] The most reliable and effective way to make nutrients available and consistent with plant needs is to control the release of nutrients into the soil solution through the use of slow release fertilizers or controlled release fertilizers.

[0011] Both slow-release fertilizers (SRF) and controlled-release fertilizers (CRF) supply nutrients gradually. However, slow-release fertilizers and controlled-release fertilizers differ in many aspects: the technology they use, release mechanism, lifespan, release control factors, and more.

[0012] Solid fertilizers include granules, prills, crystals and powders. Prilled fertilizers are granular fertilizers of a type of spherical shape made by solidifying free-falling droplets in air or fluid media. Most of the controlled-release fertilizers (CRFs) used in commercial nurseries are granular fertilizers coated with sulfur or polymers. These products have been developed to allow nutrients to be slowly released into the root zone throughout crop development. Known sulfate-containing compounds are different in water solubility capacity.

[0013] The most soluble and popular sources of sulfate fertilizers are ammonium sulfate (AS), single superphosphate (SSP), potassium sulfate, and magnesium sulfate. Polyhalite is an evaporite mineral, a single complex crystalline dehydrated form of sulfates of potassium, calcium, and magnesium having the formula: K2Ca2Mg(SO4)4·2H2O. Polyhalite is used as a fertilizer because it is considered low in chloride and contains both major and minor macronutrients as follows:

[0014] 48% SO3 in terms of sulfate

[0015] 14% K2O

[0016] 6% MgO

[0017] 17% CaO.

[0018] The use of liquid fertilizers encompasses a number of advantages over the use of dry (e.g., granular or powdered) fertilizers. For example, dry powdered fertilizers tend to spread out, such as when there is wind. In addition, liquid-based fertilizers tend to be more uniform, for example, than granular fertilizers, and provide an even distribution of fertilizer to the plants.

[0019] However, certain fertilizers such as polyhalite tend to precipitate quickly when high concentrations of polyhalite are used in suspension. SUMMARY OF THE INVENTION

[0021] According to some demonstrative embodiments, provided herein is a sulfate suspension and a process for producing the sulfate suspension.

[0022] According to some illustrative embodiments, provided herein is a high concentration sulfate suspension comprising at least 50% w / w salt, preferably at least 60% w / w salt, more preferably at least 70% w / w salt.

[0023] According to some embodiments, the sulfate salt may include any mineral selected from the group consisting of Anhydrite, Polyhalite, Gypsum, Kieserite, Epsomite, Glauberite, Blodite, Langbeinite, Kainite, Schonite, calcium sulfate, potassium magnesium and sulfur fertilizer (e.g. ) and similar minerals.

[0024] According to some embodiments, the sulfate may preferably be polyhalite.

[0025] According to some embodiments, the polyhalite may be produced from a standard grade of polyhalite, ie, polyhalite having a particle size of less than 2 mm.

[0026] According to some embodiments, the present invention may allow for the formation of a stable suspension using polyhalite having a particle size of 0.5 mm to 2 mm, for example, a non-uniform or varying particle size within the range of 0.5 mm to 2 mm.

[0027] According to other embodiments, the sulfate may preferably be kieserite.

[0028] According to some embodiments, the kieserite may have a particle size of less than 3 mm.

[0029] According to some embodiments, the suspension of the present invention is stable for at least one month, preferably at least two months, more preferably at least three months.

[0030] According to some embodiments, the stability of a suspension can be measured by the absence or minimal separation into different layers and / or the absence or minimal precipitation of mass.

[0031] According to some embodiments, the stability of the suspension can be measured by pouring the suspension into a 100 ml tube and measuring the change in height over time due to sedimentation. A stable suspension is defined as a change of 0 mm for a minimum of two weeks from preparation, preferably 1 month from preparation, and most preferably at least 2 months from preparation.

[0032] According to some embodiments, the suspensions of the invention may include one or more suspending agents, for example, to enable the creation of a flowable and stable suspension.

[0033] According to some embodiments, one or more suspending agents may include a suitable thickening agent or clay.

[0034] According to some embodiments, the concentration of the one or more suspending agents may be between 0.2% w / w-1% w / w.

[0035] According to some embodiments, one or more suspending agents may be selected from the group consisting of: organically modified smectite clay; beneficiated smectite clay; colloidal magnesium aluminum silicate; and gums such as microcrystalline cellulose, cellulose gum, xanthan gum, guar gum, and similar suspending agents.

[0036] According to some embodiments, the one or more suspending agents may preferably be a clay, most preferably an organically modified beneficiated montmorillonite clay.

[0037] According to some embodiments, the suspension of the present invention may have a viscosity of about 2000 cP and a density of about 1.9 g / cc.

[0038] According to some embodiments, the suspension may further comprise at least one dispersant selected from the group consisting of: a nonionic surfactant formed by ethoxylation of sorbitan; a blend of polyethoxylated alkylamines (C8-C18) alkyl polyoxyethylene glycols and organic acids; sodium hexametaphosphate (SHMP); a hydrotrope; a wetting agent; a super wetting agent; a nonionic surfactant; a nonionic surfactant having a hydrophilic polyethylene oxide chain; a sodium polymethacrylate dispersant, and similar dispersants.

[0039] According to some embodiments, provided herein is a method for preparing a sulfate suspension, the method comprising: premixing water (e.g., reverse osmosis water) with one or more suspending agents via mechanical agitation; adding the sulfate in three steps (equal amounts) while mixing via mechanical agitation; and wherein the concentration of the sulfate is at least 50% w / w.

[0040] According to some embodiments, the sulfate salt may be selected from the group comprising anhydrite, polyhalite, gypsum, kieserite, epsomite, glauberite, leonite, leonite, kainite, kainite, calcium sulfate, potassium magnesium and sulfur fertilizers.

[0041] According to some embodiments, the sulfate may preferably be polyhalite or kieserite.

[0042] According to some embodiments, the concentration of clay may be between 0.2% w / w-1% w / w. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A vial test is depicted, according to some demonstrative embodiments.

[0045] Figure 2 A vial test is depicted, according to some demonstrative embodiments.

[0046] Figure 3 Depicted are exemplary polyhalite suspensions, according to some demonstrative embodiments.

[0047] Figure 4 Depicted are exemplary polyhalite suspensions, according to some demonstrative embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0049] According to some demonstrative embodiments, provided herein is a sulfate suspension and a process for producing the sulfate suspension.

[0050] According to some illustrative embodiments, provided herein is a high concentration sulfate suspension comprising at least 50% w / w salt, preferably at least 60% w / w salt, more preferably at least 70% w / w salt.

[0051] According to some embodiments, the sulfate salt may include any mineral selected from the group consisting of anhydrite, polyhalite, gypsum, kieserite, epsomite, glauberite, leonite, philite, kainite, calcium sulfate, potassium magnesium, and sulfur fertilizers (e.g. ) and similar minerals.

[0052] According to some embodiments, the sulfate may preferably be polyhalite.

[0053] According to some embodiments, the polyhalite may be produced from a standard grade of polyhalite, ie, polyhalite having a particle size of less than 2 mm.

[0054] According to some embodiments, the present invention may allow for the formation of a stable suspension using polyhalite having a particle size of 0.5 mm to 2 mm, for example, a non-uniform or varying particle size within the range of 0.5 mm to 2 mm.

[0055] According to other embodiments, the sulfate may preferably be kieserite.

[0056] According to some embodiments, the kieserite may have a particle size of less than 3 mm.

[0057] According to some embodiments, the suspension of the present invention is stable for at least one month, preferably at least two months, more preferably at least three months.

[0058] According to some embodiments, the stability of a suspension can be measured by the absence or minimal separation into different layers and / or the absence or minimal settling of clumps.

[0059] According to some embodiments, the stability of the suspension can be measured by pouring the suspension into a 100 ml tube and measuring the change in height over time due to sedimentation. A stable suspension is defined as a change of 0 mm for a minimum of two weeks from preparation, preferably 1 month from preparation, and most preferably at least 2 months from preparation.

[0060] According to some embodiments, the suspensions of the invention may include one or more suspending agents, for example, to enable the creation of a flowable and stable suspension.

[0061] According to some embodiments, one or more suspending agents may include a suitable thickening agent or clay.

[0062] According to some embodiments, the concentration of the one or more suspending agents may be between 0.2% w / w-1% w / w.

[0063] According to some embodiments, the one or more suspending agents may be selected from the group consisting of: organically modified montmorillonite clay; beneficiated montmorillonite clay; colloidal magnesium aluminum silicate; and gums such as microcrystalline cellulose, cellulose gum, xanthan gum, guar gum, and similar suspending agents.

[0064] According to some embodiments, the one or more suspending agents may preferably be a clay, most preferably an organically modified beneficiated montmorillonite clay.

[0065] According to some embodiments, the suspension of the present invention may have a viscosity of about 2000 cP and a density of about 1.9 g / cc.

[0066] According to some embodiments, the suspension may further comprise at least one dispersant selected from the group consisting of: a nonionic surfactant formed by ethoxylation of sorbitan; a blend of polyethoxylated alkylamines (C8-C18) alkyl polyoxyethylene glycols and organic acids; sodium hexametaphosphate (SHMP); a hydrotrope; a wetting agent; a super wetting agent; a nonionic surfactant; a nonionic surfactant having a hydrophilic polyethylene oxide chain; a sodium polymethacrylate dispersant, and similar dispersants.

[0067] As is known in the art, stable dispersion of powders in liquids is a process in which aggregates and agglomerates of the powder are dispersed into individual units, typically followed by a wet milling process and stabilization of the resulting suspension to prevent aggregation and agglomerate sedimentation.

[0068] According to some embodiments, the liquid used in the present invention may be water, and thus, a hydrophilic solid may be used as a suspending agent, such as bentonite clay.

[0069] According to some embodiments, in ordinary suspensions, particles may experience aggregation during storage time due to van der Waals forces or dipole attraction. According to some embodiments, in order to overcome this attractive energy, it is necessary to have repulsive energy between particles or to create a three-dimensional gel that thickens the suspension and keeps the suspension uniform.

[0070] According to some embodiments, since the particle density is generally greater than the density of the medium, the particles tend to settle into a dense sediment that can be very difficult to redisperse again. According to some embodiments, the present invention uses suspending agents, such as thickeners and clays, to produce a gel network with high viscosity that prevents the particles from settling.

[0071] According to some embodiments, one of the objectives of the present invention is to prepare stable suspensions with a long shelf life (>2 months, preferably >3 months) without applying continuous stirring.

[0072] According to some embodiments, the suspension of the present invention may include using any sulfate salt, such as polyhalite or kieserite, with a particle size distribution having a particle size less than 2 mm and preferably comprising large particles in the range between 0.5 mm and 2.0 mm.

[0073] According to some embodiments, it may be challenging to produce a uniform suspension of all particle sizes, avoid sedimentation, or avoid the necessity to apply constant stirring simply to keep the suspension stable.

[0074] According to some embodiments, to prepare a flowable and stable suspension, finding or using a suitable suspending agent among the infinite possibilities can be extremely challenging.

[0075] Furthermore, one of the main challenges, particularly for the suspensions of the present invention, is to find a suitable suspending agent that will form a stable network to hold large particles and reduce the tendency to settle and coagulate into a mass that cannot be suspended.

[0076] According to some embodiments, the unique particle size and water swelling capacity of the suspending agents used in the present invention allow for the formation of stable suspensions that do not require the size reduction of the sulfate salts to uniformly below 0.5 mm.

[0077] According to some embodiments, provided herein is a method for preparing a sulfate suspension, the method comprising: premixing water (e.g., reverse osmosis water) with one or more suspending agents via mechanical agitation; adding the sulfate in three steps (equal amounts) while mixing via mechanical agitation; and wherein the concentration of the sulfate is at least 50% w / w.

[0078] According to some embodiments, the sulfate salt may be selected from the group comprising anhydrite, polyhalite, gypsum, kieserite, epsomite, glauberite, leonite, leonite, kainite, kainite, calcium sulfate, potassium magnesium and sulfur fertilizers.

[0079] According to some embodiments, the sulfate may preferably be polyhalite or kieserite.

[0080] According to some embodiments, the concentration of the suspending agent may be between 0.2% w / w-1% w / w.

[0081] According to some embodiments, it was found to be important to add the polyhalite in more than one step, preferably in three steps, in order to avoid frictional heat formed during mixing and to protect the mechanical stirrer from damage. According to some embodiments, it was also found that when the polyhalite was added using three steps, a more homogeneous suspension was formed.

[0082] According to some embodiments, generally, when adding additives such as xanthan gum to suspend the particles of the suspension, it is necessary to use a high shear mixer, which may be more expensive and also grinds all particles including the active material to obtain a uniform suspension.

[0083] According to some embodiments, the present invention enables overcoming these disadvantages through the unique use of a mechanical agitator.

[0084] According to some demonstrative embodiments, provided herein is a polyhalite (also referred to herein as "polysulphate") suspension and a process for producing the polyhalite suspension.

[0085] According to some illustrative embodiments, provided herein is a high concentration polyhalite suspension comprising at least 50% w / w polyhalite, preferably at least 60% w / w polyhalite, more preferably at least 70% w / w polyhalite.

[0086] According to some embodiments, the polyhalite may be produced from a standard grade of polyhalite, for example a polyhalite having a particle size of less than 2 mm, d50 = 760 μm.

[0087] According to some embodiments, polyhalite at high concentrations, e.g., above 15% w / w, tends to precipitate, and one of the ways to at least partially overcome this precipitation is by attempting to grind the polyhalite into powder particles, e.g., powder particles having a size of less than 0.4 mm. However, according to some other embodiments, the present invention allows for the formation of a stable polyhalite suspension using polyhalite particles, e.g., using polyhalite particles wherein at least 80% of the particles have an average size of at least 0.5 mm.

[0088] According to some embodiments, in the present invention, polyhalite particles (eg, standards) may be sieved prior to preparing the suspension, for example, by using a sieve with 710 micron openings.

[0089] According to some demonstrative embodiments, the suspension of the invention may include polyhalite added to water at a concentration of at least 50% w / w, preferably at least 70% w / w, optionally together with a dispersant (also called a "stabilizer").

[0090] According to some embodiments, it is known that high concentrations of polyhalite in aqueous environments tend to precipitate. Therefore, the present invention provides a unique solution to the challenge of producing a stable suspension of high concentrations of polyhalite.

[0091] According to some embodiments, the term "stable" as used herein may refer to a substantially homogeneous suspension, ie, a suspension that does not include two or more separate sediments but rather a single fraction.

[0092] According to some embodiments, the suspension of the invention may be stable for at least 1 month from the moment of production, preferably more than 2 months, and most preferably at least 3 months.

[0093] According to some embodiments, most suspensions contain soluble salts and can be used for foliar spraying in the case of fertilizers. However, many sulfates, such as polyhalite, are low solubility minerals and therefore, their use in suspensions is extremely challenging because the nozzles will clog or plug.

[0094] According to some other embodiments, provided herein is a use of the sulfate suspension of the present invention for fertilizing crops or fields, wherein the use may include adding substances to the suspension, for example to enhance fertilization.

[0095] According to these embodiments, the presence of the sulfate salt, such as polyhalite, in suspension allows for effective mixing and / or combination with other materials.

[0096] According to some embodiments, substances that may be added to the suspension of the present invention may include, but are not limited to, biostimulants, microorganisms, organic fertilizers, and the like.

[0097] According to some embodiments, the suspension of the invention may allow for efficient spreading of low solubility fertilizers, in particular sulfates, such as sparingly soluble sulfates, preferably polyhalite.

[0098] According to some embodiments, potassium is the first nutrient to be released when the suspension of the present invention comes into contact with the soil.

[0099] According to these embodiments, the rapid and complete release of potassium from the polyhalite mineral, such as when specifically used in the suspension according to the invention, allows a large amount of potassium to be absorbed by the plant, which, as previously mentioned, plays an important role in the development of the plant. According to some embodiments, other important nutrients for the plant are released shortly thereafter.

[0100] According to some embodiments, the suspension may include one or more suspending agents that act as rheological additives, such as clays, preferably organically modified montmorillonite clays and / or beneficiated montmorillonite clays, such as, for example, polysilicates or industrial montmorillonite clays, such as, for example, polysilicates or industrial montmorillonite clays for systems containing high levels of dissolved electrolytes, such as magnesium aluminum silicates (e.g., VAN ES); colloidal magnesium aluminum silicate, such as VAN B; microcrystalline cellulose and / or cellulose gum, e.g. 611.

[0101] According to some preferred embodiments of the present invention, the clay may preferably be an organically modified montmorillonite clay and / or a beneficiated montmorillonite clay, such as for example DYCE.

[0102] According to some embodiments, the suspending agent may be a clay and is used in a concentration between 0.2% w / w-1.0% w / w.

[0103] According to some illustrative embodiments, the unique use of clay, particularly at low concentrations, such as less than 1% w / w, allows the formation of a three-dimensional network structure that creates repulsive forces between the sulfate particles, thereby preventing their agglomeration and precipitation. According to some embodiments, the use of clay can promote fluidization of the sulfate particles in the aqueous suspension.

[0104] According to some embodiments, provided herein is a sulfate suspension comprising: a sulfate, such as polyhalite or kieserite, at a concentration of at least 50% w / w; and a clay at a concentration between 0.2% w / w and 1% w / w.

[0105] According to some embodiments, in addition to the suspending agent, the suspension of the present invention may also include one or more dispersants, wherein the dispersant may include any suitable substance that can reduce the viscosity of the sulfate salt and / or prevent or delay the separation of the suspension into two or more separate fractions, and / or prevent or reduce the formation of precipitates.

[0106] According to some embodiments, the one or more dispersants may be selected from the group comprising: nonionic surfactants, for example, formed by ethoxylation of sorbitan, for example, polysorbates such as polysorbate 20 (also known as Tween 20); blends of polyethoxylated alkylamines (C8-C18) alkyl polyoxyethylene glycols and organic acids (also known as "Optima"); sodium hexametaphosphate (SHMP); hydrotropes, for example, hydrotropes for nonionic surfactants such as n-octylphosphonic acid (also referred to herein as SURFARON); wetting agents and / or superwetting agents, such as wetting agents based on n-octyl-2-pyrrolidone, for example Easy-Wet TM ; a nonionic surfactant, preferably a nonionic surfactant having a hydrophilic polyethylene oxide chain, such as polyethylene glycol p-(1,1,3,3-tetramethylbutyl)-phenyl ether (also known as Triton X-100); a sodium polymethacrylate dispersant, for example and similar dispersants.

[0107] According to some embodiments, a combination of dispersants may be used, such as a combination of clay and n-octylphosphonic acid. According to some embodiments, the clay may be used in a concentration between 0.1 w / w-1.5% w / w, preferably between 0.3% w / w-0.7% w / w, and the n-octylphosphonic acid may be used in a concentration between 0.2% w / w-1% w / w, preferably between 0.5% w / w-0.6% w / w.

[0108] According to some illustrative embodiments, the suspension of the present invention may have a viscosity of about 2000 cp-4000 cp and a density of 1.2 g / ml-2.5 g / ml, preferably 1.8 g / ml-1.9 g / ml.

[0109] According to some illustrative embodiments, provided herein is a method for preparing a sulfate suspension, the method comprising:

[0110] - premixing water with the organically modified clay via mechanical stirring, for example at 250 rpm for 10 minutes;

[0111] - Add the sulfate in three steps (equal amounts) while mixing via mechanical stirring, for example via mechanical stirring at 200 rpm for 10 minutes.

[0112] According to some embodiments, the sulfate may preferably be polyhalite.

[0113] According to some embodiments, the suspension is a 50% w / w polyhalite suspension, preferably a 70% w / w polyhalite suspension.

[0114] According to some embodiments, the concentration of clay may be between 0.2% w / w and 1% w / w, preferably between 0.3% w / w and 0.7% w / w, most preferably 0.5% w / w.

[0115] According to some illustrative embodiments, provided herein is a method for preparing a polyhalite suspension, such as a 70% w / w suspension, the method comprising:

[0116] Reverse osmosis (RO) water is premixed with an organically modified clay (e.g., Bentone DY CE) at a concentration of, for example, 0.5% w / w using mechanical agitation, e.g., at 250 rpm for 10 minutes.

[0117] Add n-octylphosphonic acid at a concentration of, for example, 1.0% w / w

[0118] The polyhalite is added in three steps (equal amounts) while mixing via mechanical stirring, for example via mechanical stirring at 200 rpm for 10 minutes.

[0119] According to some embodiments, the sulfate suspension may be used in agricultural applications including, but not limited to, soil conditioning and fertilization.

[0120] According to some preferred embodiments, the suspension of the invention may be particularly useful when applied to animal manure, for example for reducing NH3 emissions.

[0121] In other embodiments, the sulfate suspension may be used in industrial applications such as water treatment or as an additive in building materials.

[0122] According to further embodiments, the suspension may include additional agents, such as colorants, preservatives or anti-caking agents.

[0123] According to some embodiments, the high concentration sulfate suspension may include a viscosity modifier to facilitate pumping or spraying of the suspension, including but not limited to polymers such as xanthan gum, hydroxyethyl cellulose (HEC), polyvinyl alcohol (PVA); associative thickeners such as hydrophobically modified ethoxylated urethanes (HEUR), hydrophobically modified alkali soluble emulsions (HASE); inorganic agents such as silica gel, fumed silica; organic compounds such as polyacrylates, alginates, guar gum; and similar suspensions.

[0124] In another embodiment, the high concentration sulfate suspension may include additional salts or minerals to provide multifunctional capabilities.

[0125] In other embodiments, highly concentrated sulfate salt suspensions may be formulated for time-release applications, where the salt dissolves over an extended period of time.

[0126] In another embodiment, the polyhalite may be pre-treated, such as by heating or chemical treatment, to alter its solubility or other properties prior to forming the suspension.

[0127] Example 1

[0128] For all examples, a standard grade of polyhalite was used. The standard grade was sieved with a 1 mm sieve. The fraction smaller than 1 mm (65.2% w / w) was used for the suspension.

[0129] 1.1. Vial testing of polyhalite suspensions with various dispersants

[0130] 50% w / w and 70% w / w polyhalite suspensions were prepared and tested by vial testing with the following dispersants and stabilizers as shown in Table 1 (concentrations in w / w):

[0131]

[0132] Table 1

[0133] For 10.0 g of the 50% w / w and 70% w / w suspensions, each of the above stabilizers was added to a vial and mixed. A blank sample containing only the polyhalite suspension without additives was used for comparison.

[0134] 1.2. After screening the dispersant, prepare 250.0 g of polyhalite suspension

[0135] After screening the stabilizers, good results were obtained: either complete stability or stabilizers that prevented the formation of unsuspendable sediment. 250.0 g of the suspension were prepared.

[0136] 2. Results:

[0137] 2.1. Vial test

[0138] All vials were left for one day without being moved. After 24 hours, each vial was shaken to test which stabilizer prevented the formation of mass blocks.

[0139] The results are shown in Table 2 and Figure 1 Displayed in.

[0140]

[0141] Table 2

[0142] Reference now Figure 1 , Figure 1 Vial testing of 50% w / w polyhalite suspensions with various stabilizers is depicted, as shown in Table 3 below:

[0143] Dispersants / stabilizers serial number No stabilizer, 50% w / w polysulfate 1 Twain 20 2 Optima 3 SHMP 4 Surfaron 5 Easy wet 6 Triton X-100 7 Darvan 7N 8 Benton DY-CE 9 Van gel B 10 Van gel ES 11 Avicell611 12

[0144] Table 3

[0145] According to some embodiments, Figure 1 As shown in Example 1, a 50% w / w suspension of polyhalite in water was tested with various dispersants.

[0146] As from Figure 1 It can be seen that the 50% w / w suspension of polyhalite in water forms three layers.

[0147] This test indicates that montmorillonite clay ( DY CE) can provide the best results as it maintains the suspension without phase separation.

[0148] Example 2

[0149] In Example 2, a 70% w / w suspension of polyhalite in water was tested with various dispersants, according to some embodiments.

[0150] Reference now Figure 2 , Figure 2 Vial testing of 70% w / w polyhalite suspensions with various stabilizers is depicted, as shown in Table 4 below:

[0151] Dispersants / stabilizers serial number No stabilizer, 70% w / w polysulfate 1 Tween 20,1% 2 Tween 20,2% 3 Optima 4 SHMP 5 Surfaron, 1% 6 Surfaron, 2% 7 Easy wet 8 Triton X-100 9 Darvan7N 10 Benton DY-CE 11 Van gel B 12 Van gel ES 13 Avicell 611 14

[0152] Table 4

[0153] As can be seen from the results, the suspension of 70% w / w polyhalite in water formed three layers, and it can be seen that the montmorillonite clay ( DY CE) is the best candidate because it remains in suspension without phase separation.

[0154] Example 3

[0155] Method for preparing polyhalite suspension:

[0156] The following was done with 0.5% w / w organically modified montmorillonite clay ( DY CE) Preparation of 70% w / w polyhalite suspension:

[0157] RO water was premixed with clay. Mixing was done by mechanical stirring at 250 rpm for 10 minutes.

[0158] Polyhalite was added in three steps (equal amounts) while mixing. Mixing was performed by mechanical stirring at 200 rpm for 10 minutes.

[0159] The suspension remained stable for 1 month.Viscosity at 100 rpm: 1340 cP.

[0160] Example 4

[0161] The following was done with 1.0% w / w organically modified beneficiated montmorillonite clay (Bentone DY CE) and 0.5% w / w n-octylphosphonic acid. Preparation of 70% w / w polyhalite suspension:

[0162] Water was premixed with clay. Mixing was done by mechanical stirring at 250 rpm for 10 minutes.

[0163] Octylphosphonic acid Add to premix.

[0164] Polyhalite was added in three steps (equal amounts) while mixing. Mixing was performed by mechanical stirring at 200 rpm for 10 minutes.

[0165] The suspension remained stable for 1 month.Viscosity at 100 rpm: 727 cP.

[0166] Example 5

[0167] The following was done with 0.3% w / w organically modified beneficiated montmorillonite clay (Bentone DY CE) and 0.6% w / w n-octylphosphonic acid Preparation of 70% w / w polyhalite suspension:

[0168] Water was premixed with n-octylphosphonic acid. Mixing was performed by mechanical stirring at 250 rpm for 2 minutes.

[0169] Add clay to premix. Mix at 250 rpm for 10 minutes.

[0170] Polyhalite was added in three steps (equal amounts) while mixing. Mixing was performed by mechanical stirring at 200 rpm for 10 minutes.

[0171] The suspension remained stable for two weeks.Viscosity at 100 rpm: 550 cP.

[0172] Example 6

[0173] Preparation of sieved (<1 mm) standard polyhalite suspension

[0174] The standard grade was sieved with a 1 mm sieve. The fraction smaller than 1 mm (65.2%) was used for the suspension.

[0175] A 70% polyhalite suspension was prepared with 0.5% w / w montmorillonite clay (Bentone DY CE) as follows:

[0176] • RO water was premixed with montmorillonite clay (Bentone DY CE). Mixing was done by mechanical stirring at 250 rpm for 10 minutes.

[0177] • Add polyhalite in three steps (equal amounts) while mixing.

[0178] • Mixing was performed by mechanical stirring at 200 rpm for 10 minutes.

[0179] The amounts of raw materials used to prepare the 70% w / w sieved polyhalite suspension are shown in Table 5:

[0180]

[0181] Reference now Figure 3 , Figure 3 The resulting polyhalite suspensions are shown in Table 5.

[0182] Example 7

[0183] 1.0% w / w n-octylphosphonic acid was used as follows A 70% w / w polyhalite suspension was prepared with 0.5% w / w montmorillonite clay (Bentone DY CE):

[0184] • Premix RO water with montmorillonite clay. Mixing was done by mechanical stirring at 250 rpm for 10 minutes.

[0185] ·Will n-Octylphosphonic acid Add to premix.

[0186] Add in three steps (equal amounts) while mixing Polyhalite Mixing was performed by mechanical stirring at 200 rpm for 10 minutes.

[0187] The amounts of raw materials used to prepare the 70% w / w sieved polyhalite suspension are shown in Table 6:

[0188] raw materials Amount (g) water 71.25 Montmorillonite Clay 1.25 n-Octylphosphonic acid 2.5 Polyhalite 175.0 total 250.0

[0189] Reference now Figure 4 , Figure 4 The resulting polyhalite suspensions are shown in Table 6.

[0190] Example 8

[0191] Preparation of standard (<2 mm) polyhalite suspension

[0192] This work describes preliminary results for the development of stable standard polyhalite suspensions at concentrations of 50% w / w-70% w / w as well as polyhalite suspensions based on sieved polyhalite.

[0193] Viscosity measurements were performed by Brookfield digital viscometer at 100 rpm and 50 rpm. The suspension was stored in a 100 ml plastic cup with a red plastic lid.

[0194] Suspension preparation:

[0195] To prepare the suspension a mechanical stirrer was used.

[0196] Suspensions at concentrations of 50% w / w and 70% w / w were prepared.

[0197] Procedure for preparing standard polyhalite suspension:

[0198] Add water to the polypropylene (PP) beaker

[0199] Add clay while stirring at 250 rpm

[0200] Stirring lasts 10-15 minutes

[0201] Add 3 doses of standard polyhalite* while stirring (divide the required amount into 3 doses)

[0202] Keep stirring for 30 minutes

[0203] The amounts of raw materials used to prepare a 50% w / w polyhalite suspension are shown in Table 8 (Test No. 22):

[0204] raw materials Amount (g) water 123.0 Montmorillonite Clay 2.0 Polyhalite 125.0 total 250.0

[0205] The amounts of raw materials used to prepare the 70% w / w polyhalite suspension are shown in Table 9 (Test No. 25):

[0206] raw materials Amount (g) water 73.0 Montmorillonite Clay 1.25 n-Octylphosphonic acid 0.75 Polyhalite 175.0 total 250.0

[0207] The following table will describe the data on a flowable and stable polyhalite suspension observed for 3 months. Viscosity measurements were performed with a SPDL 3 at 100 rpm and 50 rpm immediately after preparation.

[0208] Table 10 summarizes the most flowable standard polyhalite suspensions:

[0209]

[0210] According to some embodiments, the suspension is prepared based on unscreened standard polyhalite having a particle size greater than 1 mm and less than 2 mm. Typically, most suspensions undergo sedimentation when left standing due to gravity and the density difference between the particles and the dispersion medium. In this case, Brownian diffusion cannot overcome gravity, and sedimentation occurs, resulting in an increase in particle concentration from the top to the bottom of the container. The larger the particle size, the greater the difficulty of stabilization.

[0211] Although the invention has been described in terms of some specific embodiments, many modifications and variations are possible. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

Claims

1. A suspension comprising at least one sulfate salt in a concentration of at least 50% w / w; and at least one suspending agent.

2. The suspension according to claim 1, wherein the sulfate is selected from the group consisting of anhydrite, polyhalite, gypsum, kieserite, epsomite, glauberite, leonite, langbeinite, sylvite, leonite, calcium sulfate, potassium magnesium and sulfur fertilizers.

3. The suspension according to claim 2, wherein the concentration of the sulfate salt is at least 60% w / w.

4. The suspension according to claim 3, wherein the sulfate is polyhalite.

5. The suspension according to claim 3, wherein the sulfate salt is kieserite.

6. The suspension of claim 4, wherein the concentration of polyhalite is at least 70% w / w.

7. The suspension according to claim 3, wherein the concentration of the suspending agent is between 0.2% w / w and 1% w / w.

8. The suspension according to claim 7, wherein the suspending agent is a clay selected from the group consisting of: organically modified montmorillonite clay; beneficiated montmorillonite clay; colloidal magnesium aluminum silicate; microcrystalline cellulose and cellulose gum.

9. The suspension according to claim 8, wherein the clay is an organically modified beneficiated montmorillonite clay.

10. The suspension of claim 3, comprising a viscosity of about 2000 cP and a density of about 1.9 g / cc.

11. The suspension according to claim 7, further comprising at least one dispersant, wherein the at least one dispersant is selected from the group consisting of: a nonionic surfactant formed by ethoxylation of sorbitan; a blend of polyethoxylated alkylamines (C8-C18) alkyl polyoxyethylene glycols and organic acids; sodium hexametaphosphate (SHMP); a hydrotrope; a wetting agent; a superwetting agent; a nonionic surfactant; a nonionic surfactant having a hydrophilic polyethylene oxide chain; and a sodium polymethacrylate dispersant.

12. A method for preparing a sulfate suspension, comprising: Premix the water and suspending agent by mechanical stirring; adding the sulfate while mixing using a mechanical stirrer; as well as wherein the concentration of the sulphate salt is at least 50% w / w.

13. The method of claim 12, wherein the sulfate salt is selected from the group consisting of anhydrite, polyhalite, gypsum, kieserite, epsomite, glauberite, leonite, leonite, kainite, kainite, calcium sulfate, potassium magnesium and sulfur fertilizers.

14. The method of claim 13, wherein the sulfate salt is polyhalite.

15. The method according to claim 14, wherein the addition of the sulfate is done in three steps (equal amounts).

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