WO2011005174A1 - Engrais à libération lente - Google Patents

Engrais à libération lente Download PDF

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Publication number
WO2011005174A1
WO2011005174A1 PCT/SE2010/050762 SE2010050762W WO2011005174A1 WO 2011005174 A1 WO2011005174 A1 WO 2011005174A1 SE 2010050762 W SE2010050762 W SE 2010050762W WO 2011005174 A1 WO2011005174 A1 WO 2011005174A1
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WO
WIPO (PCT)
Prior art keywords
slow
salt
release fertilizer
calcium
ammonia
Prior art date
Application number
PCT/SE2010/050762
Other languages
English (en)
Inventor
Jörg BRÜCHER
Original Assignee
Sveaskog Förvaltnings AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sveaskog Förvaltnings AB filed Critical Sveaskog Förvaltnings AB
Publication of WO2011005174A1 publication Critical patent/WO2011005174A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05C—NITROGENOUS FERTILISERS
    • C05C3/00—Fertilisers containing other salts of ammonia or ammonia itself, e.g. gas liquor
    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
    • C05G5/00—Fertilisers characterised by their form
    • C05G5/30—Layered or coated, e.g. dust-preventing coatings
    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
    • C05G5/00—Fertilisers characterised by their form
    • C05G5/30—Layered or coated, e.g. dust-preventing coatings
    • C05G5/38—Layered or coated, e.g. dust-preventing coatings layered or coated with wax or resins

Definitions

  • the present invention relates to a slow-release fertilizer and a method for preparing a slow-release fertilizer.
  • Fertilizers can be modified in a number of ways in order to achieve slow- release properties.
  • fertilizers may be coated with
  • the fertilizer In order for a fertilizer to release nutrients, such as nitrogen, during a period of time of 0.5 to 2 years, the fertilizer should preferably have the following properties: - Mechanical stability to facilitate storing in large stacks or piles and withstand fertilizing using mechanical means, such as fertilizing using a centrifugal (spinning) disk distributer.
  • a coating to extend the period of time during which the fertilizer is "dissolved” in the ground i.e. a coating to enhance the slow-release properties.
  • the fertilizer should preferably be composed of compounds that are naturally occurring in the soil or ground in order to reduce unnecessary spreading of chemicals to e.g. the forest or cultivated lands.
  • An object of the invention is also to provide a fertilizer that allows nutrient uptake by plants or trees during an extended period of time.
  • Yet another object of the invention is to provide a fertilizer having a primary nitrogen source other than nitrate.
  • a further object is to provide a fertilizer that does not lead to spreading of unnatural products in the soil.
  • a slow-release fertilizer comprising a salt between ammonia and an organic acid, and a binder, wherein the salt has a solubility in water of less than 100 g/l at 20 0 C, and the binder comprises a salt between calcium and a dicarboxylic acid or a salt between calcium and sulfuric acid.
  • the organic acid is a dicarboxylic acid.
  • the salt between ammonia and a dicarboxylic acid is ammonium oxalate, (NH 4 ) 2 C2 ⁇ 4 .
  • the salt between calcium and a dicarboxylic acid is calcium oxalate.
  • the slow-release fertilizer is in the form of granules or pellets.
  • the granules or pellets are porous and comprise an internal hydrophobic coating in at least some of the pores.
  • the internal hydrophobic coating may comprise tall oil and/or salts of resin acids and/or salts of fatty acids. Further, the internal hydrophobic coating may comprise betulin.
  • the slow-release fertilizer is further comprising a surface coating.
  • the surface coating may comprise a salt of a resin acid and/or a salt of a modified resin acid.
  • the surface coating comprises a lignin compound or the product of the lignin compound reacted with urea, wherein the lignin compound is provided by a method comprising the steps of:
  • a method for preparing a slow-release fertilizer comprising a salt between ammonia and an organic acid, wherein the salt has a solubility in water of less than 100 g/l at 20 0 C, comprising the steps of:
  • the organic acid is defined as in relation with the first aspect.
  • the calcium salt is selected from calcium nitrate, calcium acetate, calcium chloride and calcium sulphate.
  • the method further comprises the step:
  • the internal hydrophobization may be performed by adding tall oil and/or resin to the slow-release fertilizer. Further, the internal hydrophobization may be performed by adding betulin to the slow-release fertilizer.
  • the method further comprises the step:
  • the coating may be performed by adding resin acids and/or fatty acids to the slow release fertilizer.
  • the coating may also be performed by adding a lignin compound or the product of the lignin compound reacted with urea, to the slow-release fertilizer, wherein the lignin compound is provided by a method comprising the steps of:
  • a slow-release fertilizer comprising a salt between ammonia and an organic acid, and a binder, wherein the salt has a solubility in water of less than 100 g/l at 20 0 C, and the binder comprises a salt between calcium and a dicarboxylic acid or a salt between calcium and sulfuric acid.
  • a fertilizer refers to a compound comprising at least one nutrient with the ability to promote plant or tree growth following uptake by plant or tree roots.
  • a slow-release fertilizer refers to a fertilizer having slow-release properties, i.e. a fertilizer able to release nutrients to the soil or ground during an extended period of time, such as during at least 1 month.
  • a salt refers to any compound composed by at least one anion and at least one cation, and wherein the net charge of the compound is zero.
  • a salt may e.g. be formed in a neutralization reaction between an acid and a base.
  • a salt between ammonia and an organic acid thus refers to any compound formed in a neutralization reaction between ammonia and an organic acid.
  • organic acid refers to any organic compound with acidic properties.
  • the organic acid may be a carboxylic acid, i.e. comprise at least one ionizable carboxylic group (-COOH).
  • the solubility of salt in water refers to the maximum amount of salt dissolved in water at eqilibhum and a specified temperature.
  • a binder refers to any type of compound that enhances the mechanical strength of the slow-release fertilizer, e.g. by binding to the crystals of the above-mentioned salt between ammonium and an organic acid.
  • the first aspect of the invention is based on the insight that a fertilizer comprising a salt between ammonia and an organic acid, and a binder, wherein the salt has a solubility in water of less than 100 g/l at 20 0 C, and the binder comprises a salt between calcium and a dicarboxylic acid or a salt between calcium and sulfuric acid has a number of positive characteristics.
  • the primary nitrogen source is ammonia, which thus decreases unfavorable leaching of nitrate to the surroundings.
  • the ammonia works as an excellent nitrogen source for the soil, and the organic acid is naturally degraded in the soil and is thus an excellent carbon source for microbes present in the soil.
  • a salt between ammonia and an organic acid, wherein the salt has a solubility lower than 100 g/l at 20 0 C increases the period during which the fertilizer dissolves in the ground or soil.
  • a binder comprising a salt between calcium and a dicarboxylic acid or a salt between calcium and sulfuric acid further enhances the properties of the fertilizer.
  • a binder surrounds or encloses the salt between ammonium and an organic acid with a sparingly soluble membrane, which enhances the slow-release properties.
  • the presence of a salt between calcium and a dicarboxylic acid or a salt between calcium and sulfuric acid further facilitates formation, such as peptization, of the slow-release fertilizer during preparation, since it facilitates hardening or baking of the fertilizers during drying.
  • the binder comprising a salt between calcium and a dicarboxylic acid or a salt between calcium and sulfuric acid gives the fertilizer mechanical properties so that it can withstand harsh handling, such as storing in large piles and spreading by centrifugal or spinning means during fertilization.
  • the salt between calcium and a dicarboxylic acid may be calcium oxalate.
  • Calcium oxalate has similar properties as gypsum, i.e.
  • calcium oxalate may form a sparingly soluble membrane around the crystals of the salt between ammonium and an organic acid, thus increasing the slow-release properties.
  • the organic acid comprises at least one carboxylic group.
  • a carboxylic group refers to COOH, i.e. the functional group present in carboxylic acids.
  • the organic acid may comprise any number of carboxylic groups, such as one, two or three carboxylic groups.
  • An organic acid comprising at least one carboxylic group may form salts with ammonia having low solubility, thus facilitating an extended release of nitrogen to the soil.
  • the organic acid may be a dicarboxylic acid.
  • a dicarboxylic acid refers to any organic molecule comprising two carboxylic groups.
  • the molecular formula of the carboxylic acid may be HOOC-R-COOH, where R is a single bond or a hydrocarbon, such as an alkyl, alkenyl or alkynyl group.
  • Dicarboxylic acids and ammonia form salts having low solubility, thus facilitating an extended release of nitrogen to the soil.
  • the salt may have the general formula
  • Salts between ammonia and an organic acid having the general formula as described above, i.e. having an even number of carbon atoms, have a low solubility in water, usually below 100 g/l at 20 0 C, preferably below 75 g/l at 20 0 C and thus improves the slow-release properties of the fertilizer.
  • the salt between ammonia and a dicarboxylic acid is ammonium oxalate, (NH 4 J 2 C 2 O 4 .
  • Ammonium oxalate has a very low solubility in water, about 50 g/l at 20 0 C, and the oxalate ion used as a counter ion to the positively charged ammonium ions is a carbon compound that is a natural product in the soil, since it is formed naturally during the degradation of organic material. Thus, the ammonium oxalate does not give rise to unnecessary deposition of unnatural substances to the soil.
  • a fertilizer comprising ammonium oxalate has shown to have outstanding slow-release properties as illustrated in the Examples of the present disclosure.
  • the salt between ammonium and an organic acid may be ammonium oxalate and the salt between calcium and an organic acid may be calcium oxalate.
  • the slow-release fertilizer is in the form of granules or pellets.
  • Granules refer to small particles or grains and pellets refer to small particles typically created by compressing, such as extruding, an original material.
  • the size and dimensions of fertilizers in the form of granuels and pellets are known to a person skilled in the art.
  • a fertilizer in the form of granules or pellets facilitates both distribution and fertilization of the fertilizer to the ground as well as storing of the fertilizer.
  • the granules or pellets may be porous and comprise an internal hydrophobic coating in at least some of the pores.
  • a porous slow-release fertilizer refers to a slow-release fertilizer comprising pores or interstices.
  • a hydrophobic coating refers to a coating that when applied to an interface lowers the critical surface tension of the interface.
  • An internal hydrophobic coating thus refers to a coating applied in at least some of the pores or interstices of the material and which decreases water absorption into the coated pores or interstices. Consequently, an internal hydrophobic coating decreases water absorption into the fertilizer and thus increases the slow-release properties of the fertilizer.
  • the internal hydrophobic coating may comprise tall oil and/or salts of resin acids and/or salts of fatty acids.
  • Tall oil also called liquid rosin or tallol, refers to the viscous liquid obtained from the Kraft process in pulp manufacture, and may comprise at least one compound selected from rosins, resin acids, fatty acids and unsaponifiable sterols.
  • Resin acids refer to terpenoid acids produced by the resin ducts of conifers or synthesized terpenoid acids.
  • the resin acids may have two types of functional groups, such as the carboxylic group and double bonds. Further, the resin acid may have the basic skeleton of a 3-ring fused system, e.g. with the formula C19H29COOH.
  • the resin acids may be at least one of abietic acid, neoabietic acid, dehydroabietic acid, palusthc acid, levopimaric acid, pimaric acid and isopimaric acids.
  • Fatty acids refers to a carboxylic acid having an alifatic tail, which may be branched or unbranched.
  • the resin acids and/or the fatty acids may originate from tall oil and the internal hydrophobic coating may thus be formed by subjecting the porous slow-release fertilizer to tall oil.
  • Tall oil and/or salts of resin acids and/or fatty acids may give rise to an internal hydrophobic coating and degradation may often result in compounds naturally occurring in the ground or soil .
  • the resin acids are by-products from the pulp industry.
  • the resin acids may be abietic acid dehydroabietic acid and pimaric acid that originate from soft timbers or conifers used in the pulp industry.
  • the internal hydrophobic coating may comprise betulin.
  • Betulin is hydrophobic and is a naturally occurring thterpene in the bark of birch trees.
  • betulin is hydrophobic and is naturally occuring in the forest and therfore does not lead to spreading of unnatural products in the soil.
  • the slow-release fertilizer is further comprising a surface coating.
  • the coating may cover the whole fertilizer or part of the fertilizer.
  • a coating may inhibit or decrease water absorption into the fertilizer and thus increase the slow-release properties of the fertilizer.
  • the coating may provide protection for the fertilizer during storage and transportation.
  • the surface coating may comprise a salt of a resin acid and/or a salt of a modified resin acid.
  • Resin acids refers to what is described above. Resin acids are naturally occurring in the ground, i.e. do only give rise to natural products upon degradation, and have hydrophobic and antimicrobial properties.
  • Modified resin acids refer to resin acids reacted with phenols or polyalcohols.
  • the coating may further comprise turpentine to increase the antimicrobial properties, such as turpentine in an amount of 0.1 -2 % (w/w), such as 0.2-1 % (w/w).
  • the coating may comprise a combination of sparingly soluble inorganic salts, such as calcium sulfate and/or calcium hydroxyphosphate, which in combination with the resin acids may give rise to a coating that is sparingly soluble and very hydrophobic, thus increasing the slow-release properties of the fertilizer.
  • a salt or a compound that is sparingly soluble may be salt or a compound having a solubility in water of less than 50 g/l at 20 0 C.
  • the surface coating may also comprise a lignin compound or the product of the lignin compound reacted with urea, wherein the lignin compound is provided by a method comprising the steps of:
  • “Lignocellulosic material” refers to material comprising lignin and cellulose.
  • Subjecting the lignocellulosic material to delignification in alkaline conditions refers to subjecting the lignocellulosic material to an alkaline fluid, such as an alkaline gas or liquid having a pH above 10, such as above 13, to liberate lignin from the cellulose.
  • the alkaline fluid added may have a temperature above 90 0 C, such as above 100 0 C.
  • Black liquor refers to an aqueous solution comprising lignin residues and the inorganic chemicals used to delignify the lignocellulosic material in alkaline conditions.
  • Evaporating black liquor refers to subjecting the black liquor to conditions so that liquid is driven off from the black liquor.
  • the evaporating may be heating and may lead to an evaporated black liquor comprising at least 50 % dry matter, such as at least 70 % dry matter.
  • Subjecting at least part of the evaporated black liquor to carbon dioxide to precipitate the lignin compound refers to injecting carbon dioxide into the evaporated black liquor to decrease the pH so that at least some lignin residue, i.e. the lignin compound, is precipitated.
  • Recovering the lignin compound refers to extracting the precipitated lignin compound.
  • a lignin compound provided by steps a1-e1 above may form a coating with low solubility in water. Further, a lignin compound provided by steps a1 - e1 reacted with urea may also form a coating with low solubility in water.
  • the black liquor may also be black liquor obtained by the Kraft process (also known as the sulphate process) of the pulping industry, in which black liquor is obtained by treating lignocellulosic material with a mixture of sodium hydroxide and sodium sulphide to delignify the lignocellulosic material.
  • the Kraft process is well known to the skilled person.
  • the lignin compound may also provided by the LignoBoostTM method.
  • the LignoBoostTM method is a method known in the art for providing a lignin compound.
  • the coating may also comprise a lignin compound or the product of the lignin compound reacted with urea, wherein the lignin compound is provided by the LignoBoostTM method.
  • a method for preparing a slow-release fertilizer comprising a salt between ammonia and an organic acid, wherein the salt has a solubility in water of less than 100 g/l at 20 0 C, comprising the steps of:
  • a mixture comprising the salt between ammonia and an organic acid refers to any type of mixture, e.g. a liquid comprising the ammonia and an organic acid.
  • the mixture may be a liquid to which the salt between ammonia and an organic acid has been added.
  • the mixture may be a sludge, i.e. a liquid of high viscosity which may comprise suspended solid material.
  • Kneading and mixing the mixture with a calcium salt refers to adding a calcium salt to the mixture before or while subjecting the mixture to kneading and mixing.
  • the calcium salt added to the mixture increases the binding between the salt crystals of the salt between ammonia and an organic acid.
  • the kneading and mixing may be performed in a kneading machine.
  • a bound mixture refers to a mixture that has a higher mechanical strength than the mixture comprising the salt between ammonia and an organic acid.
  • Forming and drying the bound mixture refers to subjecting the bound mixture to means so as to form a slow-release fertilizer in a desired shape.
  • the forming may be peptization and the drying may be performed by heating the bound mixture, either before, after or concurrently with the forming.
  • the drying may e.g. be performed at 50-110 0 C, such as at 50-70 0 C.
  • the other terms and definitions used in embodiments of the second aspect of the invention are as defined in connection with the first aspect of the invention above.
  • the organic acid is as defined in relation to the first aspect above.
  • the organic acid may be a dicarboxylic acid.
  • Dicarboxylic acids and ammonia form salts having low solubility, thus facilitating an extended release of nitrogen to the soil.
  • the ammonia and dicarboxylic acid may be by-products from the pulp industry. If the ammonia and dicarboxylic acid are by-products from the pulp industry, it may facilitate preparation of the fertilizer, since the need for transporting either the ammonia or the dicarboxylic acid is decreased.
  • the salt between ammonia and a dicarboxylic acid may be ammonium oxalate, (NH 4 ) 2 C2 ⁇ 4 .
  • Ammonium oxalate has a very low solubility in water, about 50 g/l, and the oxalic acid used as a counter ion to the positively charged ammonium ions is a carbon compound that is a natural product in the soil, since it forms naturally during the degradation of organic material. Thus, the ammonium oxalate does not give rise to unnecessary deposition of unnatural substances to the soil.
  • the mixture comprising ammonium oxalate may be a sludge prepared from by-products of the pulp industry.
  • the sludge comprising ammonium oxalate may be obtained by a process comprising the steps of: a1 ) reacting calcium oxalate and sulphuric acid in a first reactor to obtain oxalic acid and calcium sulphate;
  • the calcium oxalate may be a by-product from the sulfite process of the pulp industry and the ammonium sulphate may be a by-product from the sulphate process of the pulp industry.
  • the calcium salt is selected from calcium nitrate, calcium acetate and calcium sulphate.
  • a calcium salt such as calcium nitrate, calcium acetate and/or calcium sulphate, e.g. in an amount of about 1-15 % (w/w), such as about 2-10 % (w/w)
  • w/w %
  • calcium oxalate may be formed.
  • Calcium oxalate has similar properties as gypsum, i.e.
  • hydrated calcium sulfate may thus provide stability to the fertilizer and facilitate formation of bonds between crystals of the salt between ammonium and an organic acid.
  • calcium oxalate may form a sparingly soluble membrane around the crystals of the salt between ammonium and an organic acid, thus increasing the slow-release properties of the fertilizer.
  • the calcium salt may be calcium hydroxide.
  • the method is further comprising the step:
  • Subjecting the slow-release fertilizer to internal hydrophobization refers to coating a porous slow-release fertilizer in at least some of pores or interstices with a hydrophobic coating that decreases water absorption into the slow- release fertilizer.
  • the internal hydrophobization may be performed by adding tall oil and/or resin to the slow-release fertilizer.
  • the tall oil and/or resin may be heated prior to addition to the slow-release fertilizer and may have a temperature of about 50-160 0 C, such as about 70-140 0 C.
  • the slow-release fertilizer may be subjected to the tall oil and/or resin during 1 -30 min, such as during 5-10 min.
  • the internal hydrophobic coating may be performed by adding betulin to the slow-release fertilizer.
  • Betulin as discussed in relation with the first aspect above, is hydrophobic and is naturally occuring in the forest and therfore does not lead to spreading of unnatural products in the soil. Further, the betulin used for internal hydrophobization may be a by-product from the paper or forest industry.
  • the method is further comprising the step:
  • Coating the slow-release fertilizer refers to subjecting the slow-release fertilizer to conditions in which a coating is formed on at least part of the surface of the fertilizer.
  • the coating may be performed by adding a coating material or compound, such as polymers and/or fatty acids to the slow- release fertilizer.
  • the coating may be performed by adding resin acids and/or fatty acids to the slow release fertilizer.
  • Resin acids refers to what is described above.
  • the coating may be performed by adding a combination between resin acids and fatty acids to the slow-release fertilizer.
  • the resin acids may be modified resin acids, which may be resin acids modified with phenols or polyalcohols.
  • the coating may be performed by adding resin or modified resin to the slow-release fertilizer.
  • Resin refers to a hydrocarbon secretion from plants, usually a viscous liquid comprising volatile fluid terpenes and carboxylic acids, such as resin acids.
  • the resin may also be synthetic resin, e.g. manufactured by esterification of organic compounds.
  • Modified resin refers to resin reacted with phenols or polyalcohols.
  • Adding resin or modified resin to the slow-release fertilizer may lead to a coating of resin acids that are naturally occurring in the ground, i.e. do only give rise to natural products upon degradation, and have hydrophobic and antimicrobial properties.
  • the slow-release fertilizer comprises sparingly soluble inorganic salts, such as calcium sulfate and/or calcium hydroxyphosphate
  • the addition of resin or modified resin may lead to a coating that is sparingly soluble and very hydrophobic, due to combination of inorganic salts and resin acids.
  • the coating may also be performed by adding a lignin compound or the product of the lignin compound reacted with urea, wherein the lignin compound is provided by a method comprising the steps of:
  • Coating the slow-release fertilizer with a lignin compound provided by steps a1 -e1 above, or such lignin compound reacted with urea, may result in a coating having low solubility in water, hence facilitating a more prolonged release of nitrogen.
  • the coating may be performed by adding a lignin compound or the product of the lignin compound reacted with urea, wherein the lignin compound is provided by the LignoBoostTM method.
  • a salt between ammonia and an organic acid as defined in relation to the first aspect above and a calcium salt for the manufacture of a slow-release fertilizer.
  • the terms and definitions used in relation to the third aspect of the invention are as defined in connection with the first and second aspect of the invention above. Methods for measuring the solubility is known to a person skilled in the art.
  • the organic acid comprises at least one carboxylic group.
  • the use the slow-release fertilizer according to the present disclosure for fertilizing soil or ground facilitates release of nutrients to the soil during an extended period of time, thus decreasing the frequency at which the soil or ground needs to be fertilized. Further, the use of the slow-release fertilizer according to the present disclosure only gives rise to spreading of
  • the fertilization with the slow-release fertilizer of the present disclosure may be performed by using a centrifugal (spinning) disk atomizer.
  • Figure 1 shows the shootlength (mm) of two year old Picea abies seedlings not fertilized at all (only water) (solid circles), fertilized with slow- release fertilizers consisting of ammonium oxalate crystals coated with calcium oxalate (solid squares) or fertilized with the commercial fertilizer Silvamix (open triangles) as a function of period of growth.
  • Pellets of slow-release fertilizers consisting of ammonium oxalate crystals coated with calcium oxalate were produced by:
  • the calcium oxalate functions as a binder and has similar properties as gypsum, i.e. hydrated calcium sulfate, and provides stability to the fertilizer and help form bonds between crystals of the salt between ammonium and an organic acid.
  • Ammonium oxalate is an ammonia salt with a relatively low solubility. Calcium oxalate has an even lower solubility. Therefore, the slow-release properties of the prepared fertilizer is enhanced.
  • the prepared fertilizers were coated with an internal resin coating.
  • the internal resin coating was obtained by placing the formed pellets in molten abietic acid for 1 -2 minutes. During this time, internal volumes of the pellets were filled with abietic acid and surface bound resin acids
  • Silvagen 80 TE is a slow-release fertilizer in which the nitrogen is present as formaldehyde urea and is described as having a disintegration time of 3-5 months.
  • the Basacotes are konventional NPK-fertilizers, and slow-release properties of these fertilizers are achieved by a membrane of polysulfonic acid.
  • Basacote 6 MK has a release time of 6 months, whereas Basacote 12 M will release its fertilizer content within 12 months.
  • disintegration and nutrient release of the formulations described were however accelerated and occurred within 3-7 days. In these tests, the formulation internally and externally coated with abietic acid had a disintegration time somewhat as Basacote 6 MK.
  • Example 1 shows that fertilizers comprising ammonium oxalate and calcium oxalate as a binder, i.e. fertilizers that do not give rise to unnecessary deposition of unnatural substances to the soil, disintegrateed at a rate similar to those of commercially available fertilizers.
  • the shootlength of spruce seedlings were analysed in a pot experiment during the winter 2009.
  • the spruce seedlings were fertilized with pellets of slow-release fertilizers prepared as in Example 1 above.
  • the pellets thus consisted of ammonium oxalate crystals coated with calcium oxalate.
  • spruce seedlings were also fertilized with the commercially available slow-release nitrogen fertilizer Silvamix, which is a slow-release fertilizer in which the nitrogen is present as formaldehyde urea.
  • Two year old spruce (Picea abies) seedlings with a low nitrogen content (1.4%) were planted in squared pots with a volume of 3 liters in an nitrogen free peat with a pH of 5.5.
  • Example 2 shows that the slow-release fertilizers according to the present invention, having ammonium oxalate as a primary nitrogen source and calcium oxalate as a binder, work as well as a commercially available slow-release fertilizer for the seedlings.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Pest Control & Pesticides (AREA)
  • Fertilizers (AREA)

Abstract

La présente invention porte sur un engrais à libération lente comprenant un sel entre l'ammoniac et un acide organique, et un liant, ledit sel ayant une solubilité dans l'eau de moins de 100 g/l à 20°C, et ledit liant comprenant un sel entre le calcium et un acide dicarboxylique ou un sel entre le calcium et l'acide sulfurique. De plus, l'invention porte sur un procédé de fabrication d'un engrais à libération lente comprenant un sel entre l'ammoniac et un acide organique, le sel ayant une solubilité dans l'eau de moins de 100 g/l à 20°C. Le procédé comprend les étapes consistant à : se procurer un mélange comprenant le sel entre l'ammoniac et un acide organique ; malaxer et mélanger le mélange avec un sel de calcium afin d'obtenir un mélange lié, et façonner et sécher le mélange lié afin d'obtenir l'engrais à libération lente. La présente invention porte également sur l'utilisation d'un sel entre l'ammoniac et un acide organique, le sel ayant une solubilité dans l'eau de moins de 100 g/l à 20°C, et sur un sel de calcium pour la fabrication d'un engrais à libération lente.
PCT/SE2010/050762 2009-07-07 2010-07-02 Engrais à libération lente WO2011005174A1 (fr)

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SE0950533 2009-07-07

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4169882A (en) * 1978-11-13 1979-10-02 Tennessee Valley Authority Purification of phosphoric acid with oxalic acid
US5628813A (en) * 1992-12-21 1997-05-13 Exxon Chemical Patents Inc. Abrasion resistant topcoats for control release coatings
WO1997046075A2 (fr) * 1996-06-05 1997-12-11 Innoval Management Limited Engrais a liberation prolongee
US20030033843A1 (en) * 2001-08-09 2003-02-20 Sumitomo Chemical Company, Limited Granular coated fertilizer
CZ2004495A3 (cs) * 2004-04-15 2005-02-16 Výzkumný ústav anorganické chemie, a. s. Způsob granulace síranu amonného
WO2006038863A1 (fr) * 2004-10-07 2006-04-13 Lignoboost Ab Procede de separation de lignine d'un liquide/d'une boue contenant de la lignine

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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