IL135297A - Homogeneous solid composition containing phosphorous acid and its salts and mkp, and process for its preparation - Google Patents

Abstract

A solid soluble granular fertilizer composition characterized in that it contains a mixture, homogeneous at particle level, based on phosphorous acid and its salts, and monopotassium phosphate (MKP), and optionally, nutrients selected from monoammonium phosphate (MAP), KNO3, NH4NO3, K2SO4, NaNO3, NH4Cl, KCl, Ca(H2PO4)2, and micronutrients as boron (B) and copper (Cu) and/or iron (Fe) and/or manganese (Mn) and/or zinc (Zn) and/or molybdenum (Mo) and/or magnesium (Mg) as micronutrients and their mixtures.

Description

/00 135297/2 ιπ]3π"7 i^nm ,ΜΚΡ -1 ΓΓΤΪ71.1 n^is g π^ηιπ ΏΏΓΪ ^τπ ^ΊΤΠΠ ΙΟΊΠ HOMOGENEOUS SOLID COMPOSITION CONTAINING PHOSPHOROUS ACID AND ITS SALTS AND MKP, AND PROCESS FOR ITS PREPARATION 10143/00 135297/2 -1- HOMOGENEOUS SOLID COMPOSITION CONTAINING PHOSPHOROUS ACID AND ITS SALTS AND MKP. AND PROCESS FOR ITS PREPARATION z Field of the Invention This invention relates to a fertilizer compositio and preparation of soluble fertilizers containing phosphorous acid (H3PO3) and its salts, monopotassium phosphate (MKP), and other ingredients which may be added to the fertilizer, nutrients N, P, K and micronutrients.

The fertilizer composition provides a homogeneous and uniform granular fertilizer, at single particle level in dry solid form. This solid fertilizer dissolves completely in water.

Background of the Invention Fertilizer compositions for plants containing phosphonate and phosphate salts are disclosed in the prior art. U.S. Patent No. 5,800,837 relates to compositions with active materials which contain phosphorous acid and its salts. Such compositions provide protection for plants against fungal infection and a method for treating plants against attack by fungi and bacteria.

Compositions based on phosphorous acid or its salts, used in controlling parasitic fungi in plants, are known in the art, containing as active material the group comprising phosphorous acid and/or mineral salts of phosphorous acid which protect plants against fungus disease. 10143/00 135297/2 -2- U.S. Patent No. 5,736,164 relates to a composition which contains phosphite and phosphate salts. and derivatives thereof, for controlling parasitic fungi on plants.

U.S. Patent No. 4,119,724 discloses fungicidal compositions containing phosphorous acid and inorganic and organic salts, as well as a method for its application to plants for controlling fungus disease.

U.S. Patent No. 5,514,200 teaches that phosphate fertilizers inhibit the beneficial symbiosis between plant roots and mycorrhizal fungi, and further promotes bacterial and fungicidal growth.

It is known in the art that fertilizer compositions should be solid, stable and easily soluble in water, so that they can be readily stored and marketed. Various phosphate compounds have been prepared that are useful in fungicidal and fertilizer compositions. U.S. Patent 4,075,324, for instance, describes phosphorous acid and its inorganic and organic salts as a fertilizer and fungicide.

Summary of the Invention The proposed invention relates to fertilizer compositions and to a process for preparing granular fertilizer which is characterized in that it contains a mixture, homogeneous at particle level, based on phosphorous acid (H3PO3) also its salts, and monopotassium phosphate (KH2PO4) (MKP), and other salts containing plant nutrients (N, P, K) selected from monoammonium phosphate (MAP), KNO3, NH4N03, K2S04, NaN03, NH4C1, KC1, Ca(H2P04) and boron (B) and copper (Cu) and/or iron (Fe), manganese (Mn) and/or zinc (Zn) and/or molybdenum (Mo) as micronutrients. 10143/00 135297/2 -3- The ratio between MKP and KH2PO3, as well as between them and the other nutrients and micronutrients, is determined according to the relative content of nutrients N, K, P desired in the fertilizer.

J" These micronutrients may be provided also as chelates, such as EDTA chelates or the like. Boron may be supplied e.g. as boric acid, molybdenum e.g. as sodium molybdate, copper e.g. as copper sulfate, and zinc e.g. as zinc sulfate.

The present invention provides a solid fertilizer, essentially homogeneous at particle level, and as for granular size, which dissolves completely in water, and is substantially dry.

It is difficult to make uniformly sized and homogeneous granular fertilizers based on molten phosphorous acid and monopotassium phosphate (MKP) in a conventional process. The present invention provides a process to obtain uniform and homogeneous granular fertilizer by a molten mixture containing phosphorous acid, and monopotassium phosphate (MKP) and optionally other fertilizer ingredients in different weight ratios. The invention is carried out by adding phosphorous acid and MKP to a preformed molten mixture of phosphorous acid and MKP and optionally the other fertilizer ingredients containing nutrients selected from monoammonium phosphate (MAP), KNO3, NH4NO3, K2SO4, Na(N03), NH4CI, KC1, Ca(H2P04)2 and boron and copper and iron and/or manganese and/or zinc and/or molybdenum as micronutrients by heating the components together or by adding the above mixtures of solid salts to the molten mixture, the mixture being at a temperature of about 60° to 130°C. 10143/00 135297/2 -4- The mixture contains at least 10% and up to 90% by weight of phosphorous acid, based on the weight of the molten mixture, and preferably from 10% to 50% by weight. The amount of monopotassium phosphate (MKP) is in the range of 90% to 10% by weight based on the weightf of the molten mixture preferably in the range of 30% to 90% by weight, and optionally contains nutrients selected from monoammonium phosphate (MAP), KN03, NH4N03) K2S04, Na(N03), NH4C1, KCl, Ca(H2P04)2 and micronutrients selected from boron (B), copper (Cu), and/or iron (Fe) and/or manganese (Mn) and/or zinc (Zn) and/or molybdenum (Mo) as micronutrients. The micronutrients may be dispersed in the melt in a homogeneous way, and the advantages of the invention are attained even if some or all of the micronutrients are not melted.

The molten mixture is neutralized by a base, MR, e.g., wherein M is a cation as K+, NH4+, Ca+2, Mg+2, and R is selected from carbonate and hydroxide ions: KH2P0 + H3PO3 + K2CO3 → KH2P04 + KH2PO3+H2O + C02 The molten mixture can be converted to granules by rapidly cooling, immediately after a substantially homogeneous molten mixture is obtained, and disintegration of the solid material.

All the above and other characteristics and advantages of the invention will be better understood through the following illustrative and non-limitative examples. 10143/00 135297/2 -5- EXAMPLES Example 1 A molten mixture was prepared by mixing 80 g monopotassium phosphate (MKP), and 20 g phosphorous acid. /The reactor was heated, and the melt temperature was 62°C. The resulting molten mixture was partially neutralized by 20.8 g potassium carbonate, the pH 3.8 in the 1% solution.

The molten product was cooled by feeding it to a cool medium. After cooling, a solid product was obtained, which disintegrated to yield a granular product with hygroscopity expressed by the critical relative humidity of 60-65%.

Example 2 A mixture containing 80 g monopotassium phosphate (MKP), and 20 g phosphorous acid was heated, and the melt temperature was 62°C. The resulting molten mixture was partially neutralized by 21.2 g potassium carbonate, the pH 4.4 in 1% solution.

The molten mixture was cooled by feeding it to a cool medium. After cooling, a solid product was obtained, which disintegrated to yield a granular product with hygroscopicity expressed by the critical relative humidity of 55-60%.

Example 3 A mixture containin 80 g monopotassium phosphate (MKP), and 20 g phosphorous acid in a glass reactor was heated, the mixture melting at 62°C, partially neutralized by 22.8 g potassium carbonate, the pH 5.0 in 1% solution. 10143/00 135297/2 -6- The molten mixture was cooled by feeding it to a cool medium. After cooling, a solid product was obtained, which disintegrated to yield a granular product with hygroscopicity expressed by the critical relative humidity of 50-55%. fs" i Example 4 A mixture containing 66 g monopotassium phosphate (MKP), 21.5 g phosphorous acid, and a mixture of micronutrients, 2.0 g Mg EDTA and 0.5 Mn EDTA, in a glass reactor was heated, partially neutralized by 18.7 g potassium carbonate. The pH was 4.2 in 1% solution.

The molten mixture was cooled by feeding it to a cool medium. After cooling, a solid product was obtained, which disintegrated to yield a granular product with hygroscopicity expressed by the critical relative humidity of 55-60%.

Example 5 A mixture containing 66 g monopotassium phosphate (MKP), 21.5 g phosphorous acid, and a mixture of micronutrients, 2.0 g Mg EDTA and 0.5 Mn EDTA, in a glass reactor was heated to the melting point (62°C), partially neutralized by 13.1 g calcium bicarbonate and then heated to 130°C over 13 minutes, the pH 3.4 in 1% solution.

The molten mixture was cooled by feeding it to a cool medium. After cooling, a solid product was obtained, which disintegrated to yield a granular product with hygroscopicity expressed by the critical relative humidity of 55-60%. 10143/00 135297/2 -7- All the above has been provided for the purpose of illustration and is not intended to limit the invention in any way, except as defined in the claims to follow. Many modifications can be effected in the materials and methods described above, without exceeding the scope of the invention. 135297/4 -8-

Claims (16)

1. A solid soluble granular fertilizer composition characterized in that it contains a mixture, homogeneous at particle level, based on phosphorous acid and its salts, and monopotassium phosphate (MKP), and optionally, nutrients selected from monoammonium phosphate (MAP), KNO3, NH4NO3, K2SO4, NaN03, NH4C1, KC1, Ca(H2P04)2, and micronutrients as boron (B) and copper (Cu) and/or iron (Fe) and/or manganese (Mn) and/or zinc (Zn) and/or molybdenum (Mo) and/or magnesium (Mg) as micronutrients and their mixtures.

2. A fertilizer composition according to claim 1 wherein phosphorous salt is selected from the group consisting of K2HPO3, KH2PO3 and K3PO3.

3. A fertilizer composition according to claim 1 or 2 which contains from 10% to 90% by weight of phosphorous acid.

4. A fertilizer composition according to any of claims 1 to 3 which contains from 10% to 50% by weight of phosphorous acid.

5. A fertilizer composition according to claim 1 which contains from 30% to 90% by weight of MKP.

6. A fertilizer composition according to any one of claims 1 to 5 which optionally contains from 0 to 20% by weight of nutrients selected from one or more of monoammonium phosphate (MAP), KNO3, NH4NO3, K2S04, NaN03, H4CI, KC1, 135297/5 -9- Ca(H2P04), and boron (B) and copper (Cu) and/or iron (Fe) and/or manganese (Mn) and/or zinc (Zn) and/or molybdenum (Mo) as micronutrients.

7. A fertilizer composition according to any one of claims 1 to 5 which contains optionally micronutrients selected from one or more of boron (B), copper (Cu), iron (Fe), manganese (Mn), zinc (Zn), molybdenum (Mo), total content of said micronutrients being in the range of from 0.1% to 4% by weight.

8. Fertilizer composition according to claim 7 wherein the micronutrients are in the form of salts or chelates.

9. A process for preparing granular fertilizers comprising melting a mixture of phosphorous acid, monopotassium phosphate (MKP), nutrients selected from monoammonium phosphate (MAP), KN03, NH4NO3, K2SO4, NaN03, NH4C1, KC1, Ca(H2P04)2 and boron (B) and copper (Cu) and/or iron (Fe) and/or manganese (Mn) and/or zinc (Zn) and/or molybdenum (Mo) and/or magnesium (Mg) as micronutrients, cooling said molten mixture, and disintegrating it.

10. A process according to claim 9 wherein the mixture melts at temperatures between 60°C to 130°C.

11. A process according to claims 9 and 10 wherein the molten mixture is prepared by heating the components together.

12. A process according to any one of claims 9 to 11, wherein the molten mixture is prepared by adding to molten phosphorous acid monopotassium phosphate 10143/00 135297/4 -10- (MKP), phosphorous acid (H3PO3) and optionally nutrients selected from monoammonium phosphate (MAP), KNO3, NH4NO3, K2SO4, NaNOs, ΝΗ401, KC1, Ca(H2P04)2 and micronutrients boron (B) and copper (Cu) and/or iron (Fe) and/or manganese (Mn) and/or zinc (Zn) and/or molybdenum (Mo).

13. A process according to any one of claims 9 to 12, wherein the molten mixture is partially neutralized by a base MR, wherein M is a cation selected from K, NH4, Ca, and R is selected from carbonate and hydroxide ions.

14. A process according to claim 13, wherein the base is potassium carbonate, calcium carbonate, or ammonium carbonate, calcium hydroxide, potassium hydroxide or ammonium hydroxide.

15. A process according to any one of claims 9 to 14 wherein the mixture is immediately cooled after a substantially homogeneous molten mixture has been obtained, and the final pH controls the hygroscopicity of the product.

16. A process according to any one of claims 9 to 14 wherein the molten mixture is converted into granules by cooling and disintegrating the solid material obtained. LUZZA s LUZZATTO By