A FERTILIZER GRANULE OF POLYHALITE AND POTASSIUM SULPHATE AND A COMPACTION PROCESS FOR THE PRODUCTION THEREOF

Abstract

According to some demonstrative embodiments, there is provided herein a fertilizer granule comprising Polyhalite and potassium sulphate, wherein said Polyhalite is present in a concentration of 30-70% w/w and said Potassium Sulphate is present in a concentration of 70-30% w/w, wherein the strength of granule immediately after production 1.3 Kg granule.

Claims

1. A fertilizer granule comprising Polyhalite and potassium sulphate, wherein said Polyhalite is present in a concentration of 30-70% w/w and said Potassium Sulphate is present in a concentration of 70-30% w/w, wherein the strength of granule immediately after production 1.3 Kg granule.

2. The granule of claim 1, wherein Polyhalite is present in a concentration of 40-60% w/w and said Potassium Sulphate is present in a concentration of 60-40%

3. The granule of claim 1, further comprising a binder in a concentration of between 1-5% w/w.

4. The granule of claim 3, wherein said binder is selected from the group including organic or inorganic binders, such as, starch, bentonite, sodium silicate, lignosulfonates, molasses, hydrated lime, bitumen, Portland cement, clay, acids (nitric, hydrochloric, phosphoric, sulphuric), cellulose gum, sucrose, water, water glass, cements, or combinations thereof.

5. The granule of claim 4, wherein said binder is selected from the group including: Starch, activated starch, whether alone or in combination with potassium silicate; meta kaolin; potassium silicate; sodium silicate or a combination thereof.

6. The granule of claim 5, the binder is activated starch.

7. The granule of claim 4, wherein said binder is present in a concentration of between 0.1-5% w/w.

8. A compaction process comprising the following steps: Mixing Polyhalite with Potassium sulphate to provide a mixture; Adding organic or inorganic binder in a concentration between 1-5% w/w preferably between 2-4% w/w; Adding water between 0.5-2%, preferably 0.5-1%; Heating said mixture to a temperature between 80-180° C.; Feeding said mixture into a compactor to provide compacted flakes; Grinding of said flakes to provide ground flakes; and Sieving said ground flakes.

9. The process of claim 8, wherein said sieving results in three types of yield: Desired sized flakes—between 2-4 mm thickness, S.G. between 1.9 to 2.4 g/cm.sup.3. Oversized (OS) flakes—between 4-20% w/w of the total resulting flakes. Undersized (US) flakes—between 10 to 80% w/w of the total resulting flakes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0023] According to some demonstrative embodiments, there is provided herein a fertilizer granule comprising 30-70% w/w Polyhalite and 70-30% w/w of

[0024] Potassium sulphate and optionally a binder, preferably, 40-60% w/w Polyhalite and 60-40% w/w of Potassium sulphate.

[0025] According to some embodiments, it has been surprisingly found that although both polyhalite and SOP are both sulphate salts, the resulting granule exhibits superior strength properties.

[0026] According to some demonstrative embodiments, adding SOP to a polyhalite granule elevates the concentrations of Potassium and sulphate in the granule, while maintaining the granule as chloride free.

[0027] According to some demonstrative embodiments, a number of cash crops, such as vegetables, fruits, nuts and field crops, are known for their sensitivity to chloride. Chloride toxicity is expressed in the affected plants as leaf scorching. When the chloride concentration in the soil solution increases, plants take up chloride on the account of essential anionic nutrients, and this may result in reduced crop yield and quality.

[0028] Traditional preparation processes of chloride-free potash fertilizers (KNO.sub.3, K.sub.2CO.sub.3 and K.sub.2SO.sub.4) have certain limitations, such as complicated operation and existing potential pollution.

[0029] According to some demonstrative embodiments, the combination of SOP and polyhalite in a single granule possess numerous surprising advantages.

[0030] According to some embodiments, the granule of the present invention comprises two different sources for providing the plant with Potassium and Sulphate. According to some embodiments, the first source may be polyhalite, and the second source may be SOP. According to some embodiments, SOP and Polyhalite comprise different dissolution rates, and according to some embodiments enable a plant exposed to the granule of the present invention to absorb vital nutrients such as Potassium and Sulphate in quick rate and in a controlled, e.g., slower, rate.

[0031] According to some embodiments, the dissolution quantity of SOP is 120 g L.sup.−1 at 25° C.

[0032] According to some embodiments, the dissolution of SOP can further be enhanced by adding one or more additives which ameliorate the diffusion coefficient (D) and the diffusion layer thickness (h), such as sodium tripolyphosphate (STPP) and/or urea phosphate (UP).

[0033] Polyhalite on the other hand, upon contact with water precipitates as gypsum and syngenite and magnesium sulphate.

[0034] According to some embodiments, the granule of the present invention may further include one or more additional fertilizers, for example, selected from the group including any material of natural or synthetic origin that is applied to soils or to plant tissues to supply one or more plant nutrients essential to the growth of plants, including, for example, Single nutrient (“straight”) fertilizers such as Ammonium nitrate, Urea, calcium ammonium nitrate, superphosphate, e.g., “Single superphosphate” (SSP), phosphogypsum, Triple superphosphate (TSP) or a mixture thereof; Multinutrient fertilizers such as Binary (NP, NK, PK) fertilizers, e.g., monoammonium phosphate (MAP) and/or diammonium phosphate (DAP), NPK fertilizers which are three-component fertilizers providing nitrogen, phosphorus, and potassium; fertilizers which include one or more of the main micronutrients sources of iron, manganese, boron, molybdenum, zinc, and copper and the like; Compound fertilizers, e.g., which contain N, P, and K; Organic fertilizers such as peat, animal wastes, plant wastes from agriculture, and sewage sludge; and/or Other elements such as calcium, magnesium, and sulfur.

[0035] According to some demonstrative embodiments, the granule of the present invention may also include one or more binders, e.g., selected from the group including any suitable material or compound that may mechanically and/or chemically hold or draw other materials together to form a cohesive whole including, for example, organic or inorganic binders, such as, starch, bentonite, sodium silicate, lignosulfonates, molasses, hydrated lime, bitumen, Portland cement, clay, acids (nitric, hydrochloric, phosphoric, sulphuric), cellulose gum, sucrose, water, water glass, cements, or combinations thereof.

[0036] According to some demonstrative embodiments, the binder may preferably be selected from the group including: Starch, most preferably, activated starch, whether alone or in combination with potassium silicate; meta kaolin; potassium silicate; sodium silicate or a combination thereof.

[0037] According to some preferable embodiments, the binder is activated starch.

[0038] According to some embodiments, the granule of the present invention may comprise a binder in a concentration of between 0.1-5% w/w, preferably 0.5-3% w/w, most preferably 1-2% w/w.

[0039] According to some embodiments, the ratio between polyhalite and SOP in the granule may be 1.1:0.9 to 0.9:1.1.

[0040] According to some embodiments, there is provided herein a compaction process comprising [0041] mixing a mixture of 30-70% w/w Polyhalite and 70-30% of Potassium sulphate w/w and optionally a binder; [0042] mixing is performed in a blade blender and/or any other suitable device capable of having a rotation speed that creates a swirling motion for a perfect homogenization and a high blending precision, e.g., a Ploughshare® Mixer. [0043] Performing a wet compaction of the mixture.

[0044] According to some embodiments, the compaction process may include the addition of a binder in a concentration of 1-5% w/w.

[0045] According to some embodiments, the binder may include but not limited: for example, organic or inorganic binders, such as, starch, bentonite, sodium silicate, lignosulfonates, molasses, hydrated lime, bitumen, Portland cement, clay, cellulose gum, sucrose, water, water glass, cements, Fly Ash,

[0046] Potassium and Sodium Silicate, MgO, CaO, Alganite, Geo-polymers, oils and waxes and the like, or a combination thereof.

[0047] According to some demonstrative embodiments, the compaction process may be a dry compaction process and may include the following steps: [0048] Mixing Polyhalite with Potassium sulphate; [0049] Optionally adding micronutrients; [0050] Adding organic or inorganic binder in a concentration between 1-5% w/w preferably between 2-4% w/w; [0051] Adding water between 0.5-2%, preferably 0.5-1%.

[0052] According to some embodiments, the mixture may be heated to a temperature between 80-180° C., preferably 160° C.

[0053] Feeding the mixture into a compactor to provide compacted flakes;

[0054] Grinding of the flakes;

[0055] Sieving of the grinded flakes; and

[0056] After sieving there are three types of yield: [0057] 1. Desired sized flakes—between 14-33 mm thickness, S.G. between 1.9 to 2.4 g/cm.sup.3. According to some embodiments, the desired size of the flakes (also referred to herein as “particles” or “granules”) is between 1-6 mm, most preferably between 2-4 mm. [0058] 2. Oversized (OS) flakes—are returned to the grinding stage, e.g., between 4-20% w/w of the total resulting flakes. [0059] 3. Undersized (US) flakes—are recycled to the mixture for compaction, e.g., between 10 to 80% w/w of the total resulting flakes.

[0060] According to some embodiments, in the dry process, optionally a binder may be added in a concentration of between 0.01-7% w/w, preferably between 1-5% w/w, most preferably between 2-4% w/w.

[0061] The final product may be submitted to post-treatment. Oil may be added to the resulting granules, e.g., to improve the rheology of the product and diminish dust formation. Polishing the granules or Coating. The resulting flakes/granules may be glazed and further coated with a suitable coating. For example, the coatings may include biodegradable coatings, sustained release coatings, controlled release coatings, oily coatings, wax coatings.

[0062] The dry compaction process may include the following steps: [0063] 1. Mixing materials—Polyhalite, potassium sulphate in 200 lit mixer [0064] 2. Adding binder [0065] 3. Adding water [0066] 4. Compacting—Diameter 600 mm, width 145 mm. working force 100-90 KN/cm. roll velocity 6 rpm. [0067] 5. Crushing using hammer mill— [0068] 6. Screening [0069] 7. Drying the granule between 2-4 mm Single strength 1.3 Kg/granules [0070] 8. Recycling-80% [0071] 9. Analysis. All analyses conducted according to the standard procedure

Example 1

[0072] 50% polyhalite+50% potassium sulphate

[0073] Abrasion in—12 mesh 58% immediately, 46% after 24 hours

[0074] Eco dust 3% immediately, 2.9% after 24 hours

[0075] Strength of granule immediately after production 1.3 Kg granule

[0076] Strength of granule after 24 hours 1.8 Kg/granule

[0077] Strength of granule after 1 month 3 Kg granule

Example 2

[0078] 49% polyhalite+49% potassium sulphate+0.7-2% water

[0079] Abrasion in—12 mesh 37% immediately, 27% after 24 hours

[0080] Eco dust 2.2% immediately, 1.9% after 24 hours

[0081] Strength of granule immediately after production 1.8 Kg granule

[0082] Strength of granule after 24 hours 2.4 Kg/granule

[0083] Strength of granule after 1 month 3.9 Kg granule

Example 3

[0084] 48% polyhalite+48% potassium sulphate+2% lignosulphonate+0.7-1% water

[0085] Abrasion in—12 mesh 21% immediately, 18% after 24 hours

[0086] Eco dust 1.26%, immediately, 1.1% after 24 hours

[0087] Strength of granule immediately after production 1.7 Kg granule

[0088] Strength of granule after 24 hours 2.3 Kg/granule

[0089] Strength of granule after 1 month 4.3 Kg granule

Example 4

[0090] 50% polyhalite+41% potassium sulphate+2% starch+7% water Strength of granule immediately after production 2.6 Kg granule

Example 5

[0091] 50% polyhalite+41% potassium sulphate+2% metakaoline+7% water Strength of granule immediately after production 1.4 Kg granule.

Example 6

[0092] 50% polyhalite+41% potassium sulphate+2% potassium silicate+7% water.

[0093] Strength of granule immediately after production 2.6 Kg granule. 50%

Example 7

[0094] polyhalite+41% potassium sulphate+1% starch+1% potassium silicate+7% water

[0095] Strength of granule immediately after production 2 Kg granule