CN101391905A - Urea-formaldehyde fertilizer and urea-formaldehyde complex fertilizer and preparation method thereof - Google Patents
Urea-formaldehyde fertilizer and urea-formaldehyde complex fertilizer and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a urea-formaldehyde fertilizer, a urea-formaldehyde compound fertilizer and preparation methods thereof. The method for preparing the urea-formaldehyde fertilizer comprises the steps as follows: 1) amylum and water are mixed to get amylum paste by pasting, wherein, the mass percentage of the amylum and water is 1: 5 to 20, and the preference is 1: 5 to 10; 2) urea and formaldehyde are added in the amylum paste, and reacted for 30 to 120 min with the pH value of 10.5 to 13 and temperature of 65 to 80 DEG C to obtain solution I, wherein, the mol ratio of the urea and formaldehyde is 2 to 4: 1, and the preference is 2.45: 1; the mass percentage of the urea and formaldehyde is 30 to 60: 1, and the preference is 45 :1; and the preferential pH value is 10.5 to 11, the preferential temperature is 65 to 70 DEG C and the preferential reacting time is 60 to 120 min; and 3) an adsorbent and sulfuric acid solution are added in the solution I, urea-formaldehyde fertilizer slurry is obtained by evenly mixing, and the urea-formaldehyde fertilizer is obtained by solidification. The content of hot water insoluble nitrogen in the urea-formaldehyde fertilizer obtained by the preparation method is greatly reduced, the fertilizer availability is improved; and the release of free un-reacted nitrogen and quick-acting nitrogen are slowed, thus leading the slow release property of the obtained fertilizer to be enhanced.
Description
Technical field
The present invention relates to a kind of urea-formaldehyde fertilizer and urea-formaldehyde complex fertilizer and preparation method thereof.
Background technology
Urea-formaldehyde fertilizer is the slow release fertilizer that urea and formaldehyde condensation form.Commercial urea-formaldehyde fertilizer is made up of urea and formaldehyde condensation products that a series of molecular weight do not wait.According to the solvability urea-formaldehyde fertilizer in water can be divided into cold water solubles (CWSN), hot water molten-cold water molten (HWSN-CWSN) and hot water insoluble (HWIN) three parts, three components contents generally equate in the urea-formaldehyde fertilizer of business level (U-F).But find that after deliberation the mineralization velocity of hot water wherein insoluble (HWIN) part only is every year 10%, plant growth is difficult to play the effect of fertilizer for this season, is difficult to limited the application of urea aldehyde slow release fertilizer on field crop by plant utilization.And cold water solubles (CWSN) part contains three kinds of compositions usually, promptly free unreacted urea, monomethyl two ureas, dimethyl triuret, decomposition and inversion is very fast in soil, and especially free unreacted urea decomposition is faster, is difficult to satisfy the requirement of certain plants to fertilizer slow release.Urea-formaldehyde fertilizer is used on agricultural, and the contradiction that is difficult to coordinate most is to guarantee that fertilizer has higher utilising efficiency when keeping the fertilizer slow.
At present, according to the difference of releasing mechanism, sustained release generally is divided into 4 kinds of different systems: (1) diffusion control system; (2) chemical control system; (3) activating solvent system; (4) magnetic control system system.
What research was maximum in the control delivery theory is the diffusion control system.The diffusion control system is divided into container (Reservoir) and two kinds of systems of matrix (Matrix).(Fig. 1, A are to be 0 o'clock system the time, and B is the system when the time being T in container (Reservoir) system, 1 is the coating material, and 2 for treating releaser), treat that h substance is aggregated the thing embedding, treat the film of h substance, slowly be diffused in the environment, reach the effect of slowly-releasing by polymer formation; Then belong to container (Reservoir) control delivery as the fertilizer coating technology.(Fig. 2 in matrix (Matrix) system, A is to be 0 o'clock system the time, B is the system when the time being T, 1 for being dissolved in the urea in the polymkeric substance, and 2 is polymeric system), polymkeric substance is because the effect of the polar functional group on its skeleton, has huge adsorptive power, make and treat that h substance lumps together with dissolving or dispersive form and polymer scale, treats that h substance slowly is discharged in the environment by the diffusion in polymkeric substance, reaches the effect of slowly-releasing.And the chemical control system comprises degraded system (Biodegradable system) (Fig. 3, A is to be 0 o'clock system the time, B is the system when the time being T, and 1 for being dispersed in medicine in the polymkeric substance), the hydrolysis that h substance passes through polymkeric substance for the treatment of wherein slowly discharges.
In the production research of China's slow release fertilizer, making up container (Reservoir) system (being coated urea) is the research focus, but the research of matrix (Matrix) system and degraded system (Biodegradable system) report is less.
Summary of the invention
An object of the present invention is to provide a kind of method for preparing the urea-formaldehyde fertilizer of long-acting slow-release.
The method for preparing urea-formaldehyde fertilizer provided by the present invention comprises the steps:
1) starch is mixed with water, gelatinization obtains starch paste; The mass ratio of described starch and described water is starch: water=1:5-20, is preferably 1:5-10;
2) adding urea and formaldehyde in described starch paste, is that 10.5-13, temperature are to react 30-120 minute under 65-80 ℃ the condition in pH value, obtains solution I; The mol ratio of described urea and described formaldehyde is 2-4:1, is preferably 2.45:1; The mass ratio of described urea and described starch is 30-60:1, is preferably 45:1;
Described pH value is preferably 10.5-11, and described temperature is preferably 65-70 ℃, and the time of described reaction is preferably 60-120 minute;
3) add sorbent material and sulphuric acid soln in described solution I, mixing obtains the urea-formaldehyde fertilizer slurry, solidifies to obtain urea-formaldehyde fertilizer.
Another object of the present invention provides a kind of method for preparing urea-formaldehyde complex fertilizer.
The method for preparing urea-formaldehyde complex fertilizer provided by the present invention comprises the steps:
1) starch is mixed with water, gelatinization obtains starch paste; The mass ratio of described starch and described water is starch: water=1:5-20, is preferably 1:5-10;
2) adding urea and formaldehyde in described starch paste, is that 10.5-13, temperature are to react 30-120 minute under 65-80 ℃ the condition in pH value, obtains solution I; The mol ratio of described urea and described formaldehyde is 2-4:1, is preferably 2.45:1; The mass ratio of described urea and described starch is 30-60:1, is preferably 45:1;
Described pH value is preferably 10.5-11, and described temperature is preferably 65-70 ℃, and the time of described reaction is preferably 60-120 minute;
3) add sorbent material and sulphuric acid soln in described solution I, mixing obtains the urea-formaldehyde fertilizer slurry, solidifies to obtain urea-formaldehyde fertilizer; When described solution I begins to solidify, stop to add described sulphuric acid soln.
Above-mentioned two kinds of methods all can also comprise the step of granulation; In order not destroy the matrix system that fertilizer and sorbent material constitute, (fertilizer slurry curing to having plasticity-but do not have before the completely solidified) carried out when the water content of the described slurry of described granulation in step 3) was 5-40%.
Described process for granulating can be direct broken granulation, extruding pelletization or the direct extrusion process of mould.Described direct chopping process for granulating is for being cut into described urea-formaldehyde fertilizer slurry the particle of different-grain diameter; The method of described extruding pelletization is carried out granulation for adopting extruding granulator.Described direct chopping prilling process and extruding pelletization method can obtain the product of different-grain diameter, as＜1mm, 1-2mm, 2-4mm, 4-8mm and 8mm or the like.The extruding pelletization method also can obtain difform product, as short cylinder, strip, bar-shaped, can select according to actual needs; the diameter of column fertilizer wherein can be as required; regulate arbitrarily by the discharge port rugosity of adjusting tablets press, for example, 1mm, 2mm, 8mm, 20mm etc.The method of the direct extrusion molding of mould can be selected the shape and the size of mould arbitrarily according to the needs that use.
In above-mentioned two kinds of methods, in the described step 3), when described solution I begins to solidify, stop to add described sulphuric acid soln.
In above-mentioned two kinds of methods, described sorbent material is non-metallic minerals powder and/or organism powder; Described non-metallic minerals powder can be at least a or several mixture in zeolite, wilkinite, diatomite and the attapulgite; Described organism powder can be stalk, sawdust and the peat composed of rotten mosses or the fertilizer that becomes thoroughly decomposed at least a or several mixtures.
In above-mentioned two kinds of methods, the mass ratio of described non-metallic minerals powder and described urea can be 1:2-10, is preferably 1:3; The mass ratio of described organism powder and described urea can be 1:3-40, is preferably 1:10-40.
In above-mentioned two kinds of methods, the diameter of described non-metallic minerals powder can be the 60-2000 order, is preferably the 150-200 order; The diameter of described organism fine powder can be 0.1-5mm, is preferably 0.1-1mm.
In above-mentioned two kinds of methods, described starch can be some non-putrid cheap various starch such as dust collection thing of wheat-flour, Semen Maydis powder, sweet potato powder or milling plant.
The urea-formaldehyde fertilizer that is obtained by arbitrary described method for preparing urea-formaldehyde fertilizer of the present invention also belongs to protection scope of the present invention, and the pH value of this urea-formaldehyde fertilizer is 6.8-7, and the insoluble nitrogen content of hot water wherein is smaller or equal to 8% (quality percentage composition).
In preparing the method for urea-formaldehyde complex fertilizer, described phosphorus potash fertilizer can be ground phosphate rock, calcium superphosphate, monoammonium phosphate, diammonium phosphate, Repone K, vitriolate of tartar, salt of wormwood, potassic-magnesian fertilizer, potash-lime fertilizer etc., and described middle trace element fertilizer can be lime carbonate and/or sal epsom and/or manganous sulfate and/or Manganous chloride tetrahydrate and/or boric acid and/or borax and/or zinc sulfate and/or zinc chloride and/or ammonium molybdate and/or ferrous sulfate etc.
Wherein the amount of phosphorus potash fertilizer of Tian Jiaing and/or trace element fertilizer can be decided according to practical situation.
The urea-formaldehyde complex fertilizer that is obtained by arbitrary described method for preparing urea-formaldehyde complex fertilizer of the present invention also belongs to protection scope of the present invention.
Zeolite is the title of the silicon aluminate mineral of a class rack columnar structure, its architecture basics is silicon (aluminium) oxygen tetrahedron, silicon (aluminium) oxygen tetrahedron is connected to form various Closed loops by oxo bridge in the plane, various rings are connected in the three-dimensional space by oxo bridge and form the polyhedron of different shape rule, the hole or the cage of zeolite have been constituted, these cages or cave connect combination with tridimensional different modes again, have formed one dimension, two dimension, the 3 D pore canal system of zeolite again.Zeolite has powerful absorption and ion exchanging function.
Bentonitic mineralogical composition mainly is montmorillonite, and wilkinite is divided into sodium base and calcium-base bentonite according to the difference of its interlayer exchangeable cation, and it is typical 2:1 three-decker, is made up of an alumina octahedral of folder between two silicon-oxy tetrahedrons.Aluminium and the silicon in the tetrahedron in the octahedron can be replaced by other ion, form interlayer charge, and superfluous interlayer charge adsorbs positively charged ion and reaches charge balance.Wilkinite has bigger surface-area and stronger ion adsorption capacity.
Diatomite is a kind of hydration Mg, Al, and the clay pit of Si is to be formed by the remains precipitation that is grown in the unicellular organism diatom in ocean or the amber.Diatomite is the chain-like structure of 2:1, is made of the silicon-oxy tetrahedron that is connected with hydroxyl by oxygen, and extraordinary perviousness and adsorptive type are arranged.
Organism fine powder (as stalk, sawdust or the peat composed of rotten mosses or the fertilizer that becomes thoroughly decomposed) has stronger adsorptivity equally.
The method for preparing urea-formaldehyde fertilizer of the present invention, by changing proportioning raw materials and the synthesis condition of fertilizer in synthetic, the content of the insoluble nitrogen of hot water in the urea-formaldehyde fertilizer is significantly reduced (1-8% that only accounts for fertilizer quality), the AI value of fertilizer〉50%, improved the quality of fertilizer, thereby the utilization ratio of nitrogen in the raising fertilizer improves the validity of fertilizer.
In the inventive method, before being chosen in fertilizer and solidifying is to wherein adding sorbent material under the liquid state, by stirring sorbent material is evenly distributed in the fertilizer, utilize the viscosity (viscosity increases gradually in the fertilizer solidification process) of fertilizer self that sorbent material evenly is included in wherein then, thereby make the fertilizer that makes constitute uniform matrix system and degraded system.In this system structure, sorbent material has adsorbed the quick-acting nitrogens of free unreacted in the fertilizer to greatest extent, and its release is slowed down, and in the fertilizer decomposition course, also makes the quick-acting nitrogen that is decomposed to form (as NH by adsorption simultaneously
4 +-N) release is delayed, and the slow-releasing of the fertilizer that makes is strengthened.
In the inventive method, be chosen in fertilizer and be cured to and have plasticity-but before not having completely solidified, carry out granulation processing, be chosen in and carry out granulation this opportunity, can not destroy the body system structure and the degraded system structure of fertilizer; Utilize the viscosity of fertilizer self, can add other any binding agent; Utilize the plasticity-of fertilizer, can take flexile granulation mode, adapt to different users's demand; as; directly broken mode also can adopt extruding pelletization or adopt the mould extruder grain, the particle diameter of fertilizer and, shape, the degree of packing can be according to user's needs regulated at will.
In addition, granulation process is strengthened the degree of packing of fertilizer.Because urea-formaldehyde fertilizer itself is that the needs degraded could be by plant absorbing, and water-soluble is lower, so, outer layer segment of the fertilizer of certain grain type and additive have certain iris action to the release of inner fertilizer nutrient, and the size of fertiliser granulates and the degree of packing all can influence the slow of fertilizer.Experiment shows, the slow-releasing of the fertilizer that the present invention obtains is apparently higher than common urea, and particle is big more, consolidation, fertilizer slow release that the AI value is big more are strong more more; Fertilizer of the present invention can be accomplished single-dose application in the plantation practice, do not burn seedling, and common urea can suppress the growth of crop under the situation that waits the nitrogen amount.And, meet the law of nutritive absorption of crop because fertilizer slowly discharges, thereby reduce the loss of fertilizer, increase utilization rate of fertilizer, reduce fertilizer amount.
The pH value of the urea-formaldehyde fertilizer that the inventive method makes is suitable for the use of most of farm crop between 6.8-7.
The present invention prepares in the method for urea-formaldehyde complex fertilizer, also be chosen in the phosphorus potash fertilizer that adds other when being in liquid state before urea-formaldehyde fertilizer solidifies, fertilizer etc., utilize in the urea-formaldehyde fertilizer solidification process viscosity of self to make then to add fertilizer evenly to be included in the urea-formaldehyde fertilizer, overcome in the ordinary compound fertilizer the especially micro-composition of some fertilizer composition effectively and added and be difficult for a uniform difficult problem.
Sorbent materials such as non-metallic minerals powder that adds in fertilizer and organism powder are reasonable soil improvement agents, and therefore, in actual the use, after fertilizer of the present invention decomposed, these materials all can further play the effect of improving the soil.
Based on above advantage, the present invention prepares the method for urea-formaldehyde fertilizer and urea-formaldehyde complex fertilizer and the urea-formaldehyde fertilizer and the urea-formaldehyde complex fertilizer that make thus are suitable for applying.
Description of drawings
Fig. 1 is a container diffusion control delivery systme square section synoptic diagram.
Fig. 2 is diffusion control delivery systme square section synoptic diagram-matrix system.
Fig. 3 is a degraded system square section synoptic diagram.
Fig. 4 is the elution curve of different-grain diameter urea-formaldehyde fertilizer.
Embodiment
Employed experimental technique is ordinary method if no special instructions among the following embodiment.
The preparation of embodiment 1, fertilizer and detection
One, preparation
1,400g Semen Maydis powder and 4kg water are added in the beaker (mass ratio of Semen Maydis powder and water is 1:10), be heated to boiling, insulation 15min, gelatinization forms starch paste, and all starch pastees are changed in the reactor.
2, add 18kg urea and 10 liter of 37% formaldehyde again in reactor, the mol ratio of urea and formaldehyde is 2.45:1, and the mass ratio of urea and Semen Maydis powder is 45:1; With the pH value to 11 of 10%NaOH solution conditioned reaction still internal reaction system, be warming up to 70 ℃ then rapidly, insulation 60min obtains solution I.
3,6kg non-metallic minerals powder sorbent material (mass ratio of non-metallic minerals powder sorbent material and urea is 1:3) is put into another empty container, solution I is added in this container then, add concentration simultaneously and be 20% H
2SO
4Solution, the limit adds the sulfuric acid limit and stirs, when beginning to solidify, solution I stops to add acid, make non-metallic minerals powder sorbent material uniform distribution therein, obtain the urea-formaldehyde fertilizer slurry, continue to stir, the viscosity of urea-formaldehyde fertilizer slurry increases gradually, solidify gradually, the viscosity of slurry self can keep the non-metallic minerals powder sorbent material that adds uniform distribution therein, and the urea-formaldehyde fertilizer slurry that obtains has Metrix system structure and degraded system structure.
Wherein, non-metallic minerals powder sorbent material is the mixture of zeolite, wilkinite, diatomite and attapulgite, and the diameter of each mineral powder is 150 orders; The mass ratio of zeolite, wilkinite, diatomite and attapulgite is 1:1:1:1.
4, granulation
In the water content of above-mentioned urea-formaldehyde fertilizer slurry is 30% o'clock (be slurry curing to having plasticity-but before not having completely solidified), and slurry is processed granulation, carries out according to following three kinds of methods respectively:
(1) direct broken granulation: have a chopping of plastic fertilizer slurry with above-mentioned, screening is then divided into＜fertiliser granulates of 1mm, 1-2mm, three grades of 2-4mm by size, with particle diameter〉part of 4mm further chopping until all by the 4mm mesh screen; The product degree of packing that present method makes is less relatively.
(2) extruding pelletization:,, make 1mm respectively, 2mm, the particle of 4mm diameter by changing the size of sieve aperture on the template with roller-flat-die type powdered extruding granulator.
(3) extruding pelletization: use the screw extruding granulator,, make 1mm respectively, 2mm, the particle of 4mm diameter by changing the size of sieve aperture on the template.
The particle that above prilling process is made carries out shaping with granulating disc or cylinder tablets press, and more than operation is normally carried out at 30% o'clock in the water content of fertilizer, and the product after the granulation carries out seasoning or directly oven dry, obtains urea-formaldehyde fertilizer.
Directly the method for chopping adopts and will have the particle of plastic raw material chopping to a certain size, and the product degree of packing that present method makes is little.And extruding pelletization or extrusion molding granulation in mould, because of the difference of the squeeze that applied, the degree of packing of product is also different, but the degree of packing all the degree of packing of the product that obtains of more directly chopping method is big.The product that adopts the screw extruding granulator is owing to the different cause of feed system, and product is bigger than adopting the degree of packing that roller-flat-die type powdered extruding granulator obtains.
The urea-formaldehyde fertilizer pH value of slurry when recording granulation and the pH value of the urea-formaldehyde fertilizer after the granulation are 7.
Two, effect detection
(1) detection of fertilizer nitrogen content and validity
The fertilizer crushed after being dried of the different grain types that will make according to method described in the step 1 is sieved by 0.25mm.
Measure total nitrogen content of fertilizer with Kjeldahl method.
The mensuration of the insoluble nitrogen of cold water in the fertilizer: take by weighing the fertilizer sample of 1.000g by 0.25mm sieve in the 100ml beaker, moistening with small amount of ethanol, add 20ml (25 ± 2 ℃) water, stirred 15 seconds every one minute, after 15 minutes, the quick filter paper filtering of clear liquor, use synthermal water washing insolubles 4-5 time again after, insolubles is all transferred on the filter paper, continued thorough washing again and make filtrate to 250ml.Measure the nitrogen content that remains fertilizer on the filter paper with Kjeldahl method, be the content of the insoluble nitrogen of cold water.
The mensuration of the insoluble nitrogen of hot water in the fertilizer: take by weighing the fertilizer sample of 1.000g by 0.25mm sieve in the 100ml beaker, moistening with small amount of ethanol, add ebullient 0.063M phosphate buffer solution 100ml, stir, cover watch-glass, put into ebullient water-bath (the beaker liquid level all immerses boiling water), stirred gently for 15 seconds every 10 minutes, after 30 minutes, use quick filter paper filtering, time of filtration will be placed in the ebullient water-bath by surplus solution.At last insolubles is all transferred on the filter paper, continued again to make filtrate reach 250ml with the damping fluid washing of boiling.Measure the content of the insoluble nitrogen of hot water on the filter paper with Kjeldahl method.
The calculation formula of fertilizer AI value is as follows: AI value=(the insoluble nitrogen amount of the insoluble nitrogen amount-hot water of cold water) * insoluble nitrogen amount of 100%/cold water.
3 repetitions are established in experiment, and the result shows, the total nitrogen content average out to 32.66% of the urea-formaldehyde fertilizer that makes with present method, the content of the insoluble nitrogen of cold water (%) average out to 12.69%, the content of hot water insoluble nitrogen (%) average out to 4.67%, AI value average out to 64%.The validity height that shows fertilizer of the present invention.
(2) mensuration of different-grain diameter fertilizer nutrient release rate
The diameter that 1-2mm fertilizer sample of making after direct fragmentation with the urea-formaldehyde fertilizer that makes in the step 1 and screw extruding granulator are made is that the fertilizer sample of 4mm is as experiment material, with urea in contrast; In the experimental technique of three kinds of fertilizer, except used fertilizer difference, all the other are all identical.
Dress earth pillar: 16 of the plastics tubings of cut-off footpath 5cm, high 35cm, earlier seal mouth at the bottom of the plastics tubing with gauze, again to wherein adding following material successively: earlier to the 40g sand of wherein packing into, again by certain degree of packing air-dry soil of crossing the 2mm sieve of 500g of packing into, fertilizer sample with 0.5gN is sprinkling upon the top then, again thereon according to the same degree of packing air-dry soil of crossing the 2mm sieve of 100g of packing into, the 40g sand of packing at last.Every kind of fertilizer repeats for four times, does blank simultaneously.
Drip washing: drip washing for the first time: add 150ml water earlier and make water saturation in the earth pillar, after 2 hours, treat that moisture all oozes down, again with the disposable adding leaching of 100ml water earth pillar, leaching back was fully sealed earth pillar with the Para film, puts into 25 ℃ of incubators, took out earth pillar later on every 3 days, with the disposable adding leaching of 100ml water earth pillar, leaching back fully continues to cultivate after sealing earth pillar with the Para film.
The making of elution curve: measure in each earth pillar that fertilizer is housed to compare with space management and drench that the total nitrogen increasing amount is the longitudinal axis in the fluid, the time is transverse axis, makes the elution curve of fertilizer.
The result is (A is a urea, and B is urea aldehyde 1-2mm, and C is urea aldehyde 4mm) as shown in Figure 4, and the result shows that urea is after initial twice drip washing, and about 80% nutrient all is leached out; It is also bigger that the more open urea-formaldehyde fertilizer of diameter 1-2mm, quality that makes through direct broken granulation mode drenches output in earlier stage, but still more much smaller than urea leaching amount; The urea-formaldehyde fertilizer leaching speed of the diameter 4mm that makes through the extruding pelletization mode is obviously slow, elution curve is type linearly almost, this be since the fertiliser granulates that makes of extruding pelletization mode than consolidation, the particle diameter of fertilizer is bigger, wherein the iris action of indissoluble part is more obvious, quick-acting attitude nitrogen wherein can not be discharged very soon, but progressively discharge along with the slow decomposition of fertilizer.
This experiment shows that also fertilizer is formed under the identical situation, and its structure, diameter, the degree of packing etc. have caused the release rate of nutrients difference of fertilizer.
The preparation of embodiment 2, fertilizer and detection
One, preparation
1,500g sweet potato powder and 2.5kg water are added in the beaker (mass ratio of sweet potato powder and water is 1:5), be heated to boiling, insulation 15min, gelatinization forms starch paste, and all starch pastees are changed in the reactor.
2, add 15kg urea and 10 liter of 37% formaldehyde again in reactor, the mol ratio of urea and formaldehyde is 2:1, and the mass ratio of urea and sweet potato powder is 30:1; With the pH value to 10.5 of 10%NaOH solution conditioned reaction still internal reaction system, be warming up to 65 ℃ then rapidly, insulation 30min obtains solution I.
3,7.5kg non-metallic minerals powder sorbent material (mass ratio of non-metallic minerals powder sorbent material and urea is 1:2) is put into another empty container, solution I is added in this container then, add concentration simultaneously and be 20% H
2SO
4Solution, the limit edged stirs, and stops to add sulfuric acid when solution I begins to solidify.Stirring makes non-metallic minerals powder sorbent material uniform distribution therein, obtain the urea-formaldehyde fertilizer slurry, continue to stir, the viscosity of urea-formaldehyde fertilizer slurry increases gradually, solidify gradually, the viscosity of slurry self can keep the non-metallic minerals powder sorbent material that adds uniform distribution therein, and the urea-formaldehyde fertilizer slurry that obtains has Metrix system structure and degraded system structure.
Wherein, non-metallic minerals powder sorbent material is the mixture of zeolite, wilkinite, diatomite and attapulgite, and the diameter of each mineral powder is 60 orders; The mass ratio of zeolite, wilkinite, diatomite and attapulgite is 1:1:1:1.
4, granulation
In the water content of above-mentioned urea-formaldehyde fertilizer slurry is 5% o'clock (be slurry curing to having plasticity-but before not having completely solidified), and slurry is processed granulation, among prilling process such as the embodiment 1 described in the step 1.
The urea-formaldehyde fertilizer pH value of slurry when recording granulation and the pH value of the urea-formaldehyde fertilizer after the granulation are 7.
Two, effect detection
(1) detection of fertilizer nitrogen content and validity
The fertilizer crushed after being dried that will make according to method described in the step 1 is sieved by 0.25mm.Detect total nitrogen content, the content of the insoluble nitrogen of cold water and the content of the insoluble nitrogen of hot water in the fertilizer according to method described in embodiment 1 step 2 then, calculate the AI value of fertilizer.
3 repetitions are established in experiment, and the result shows, the total nitrogen content average out to 31% of the urea-formaldehyde fertilizer that makes with method described in the present embodiment, the content of the insoluble nitrogen of cold water (%) average out to 23%, the content of hot water insoluble nitrogen (%) average out to 8%, AI value average out to 65%.The validity height that shows fertilizer of the present invention.
(2) mensuration of different-grain diameter fertilizer nutrient release rate
Measure according to method described in the step 2 among the embodiment 1.
3 repetitions are established in experiment.The result shows, under the condition of same composition, the urea-formaldehyde fertilizer leaching speed of the diameter 4mm that makes through the extruding pelletization mode of the present invention is very slow, elution curve is type linearly almost, it is also bigger that the leaching speed of the urea-formaldehyde fertilizer that diameter 1-2mm, the quality that the direct broken granulation mode of warp of the present invention makes is more open is drenched output in early stage, still all much smaller than the leaching speed of urea; Show that fertilizer of the present invention has tangible slow-releasing.
The preparation of embodiment 3, fertilizer and detection
One, preparation
1,200g wheat-flour and 4kg water are added in the beaker (mass ratio of wheat-flour and water is 1:20), be heated to boiling, insulation 15min, gelatinization forms starch paste, and all starch pastees are changed in the reactor.
2, add 9kg urea and 3 liter of 37% formaldehyde again in reactor, the mol ratio of urea and formaldehyde is 4:1, and the mass ratio of urea and wheat-flour is 45:1; With the pH value to 13 of 10%NaOH solution conditioned reaction still internal reaction system, be warming up to 80 ℃ then rapidly, insulation 120min obtains solution I.
3,0.9kg non-metallic minerals powder sorbent material (mass ratio of non-metallic minerals powder sorbent material and urea is 1: 10) is put into another empty container, then solution I is added in the beaker, add concentration simultaneously and be 20% H
2SO
4Solution, the limit edged stirs, when beginning to solidify, solution I stops to add sulfuric acid, stirring makes non-metallic minerals powder sorbent material uniform distribution therein, obtains the urea-formaldehyde fertilizer slurry, continues to stir, the viscosity of urea-formaldehyde fertilizer slurry increases gradually, solidify gradually, the viscosity of slurry self can keep the non-metallic minerals powder sorbent material that adds uniform distribution therein, and the urea-formaldehyde fertilizer slurry that obtains has Metrix system structure and degraded system structure.
Wherein, non-metallic minerals powder sorbent material is the mixture of zeolite, wilkinite, diatomite and attapulgite, and the diameter of each mineral powder is 2000 orders; The mass ratio of zeolite, wilkinite, diatomite and attapulgite is 1:1:1:1.
4, granulation
In the water content of above-mentioned urea-formaldehyde fertilizer slurry is 40% o'clock (be slurry curing to having plasticity-but before not having completely solidified), and slurry is processed granulation, among prilling process such as the embodiment 1 described in the step 1.
The urea-formaldehyde fertilizer pH value of slurry when recording granulation and the pH value of the urea-formaldehyde fertilizer after the granulation are 7.
Two, effect detection
(1) detection of fertilizer nitrogen content and validity
The fertilizer crushed after being dried that will make according to method described in the step 1 is sieved by 0.25mm.Detect total nitrogen content, the content of the insoluble nitrogen of cold water and the content of the insoluble nitrogen of hot water in the fertilizer according to method described in embodiment 1 step 2 then, calculate the AI value of fertilizer.
3 repetitions are established in experiment, and the result shows, the total nitrogen content average out to 40% of the urea-formaldehyde fertilizer that makes with method described in the present embodiment, the content of the insoluble nitrogen of cold water (%) average out to 5%, the content of hot water insoluble nitrogen (%) average out to 2%, AI value average out to 60%.The validity height that shows fertilizer of the present invention.
(2) mensuration of different-grain diameter fertilizer nutrient release rate
Measure according to method described in the step 2 among the embodiment 1.
3 repetitions are established in experiment.The result shows, under the condition of same composition, the urea-formaldehyde fertilizer leaching speed of the diameter 4mm that makes through the extruding pelletization mode of the present invention is very slow, elution curve is type linearly almost, it is also bigger that the leaching speed of the urea-formaldehyde fertilizer that diameter 1-2mm, the quality that the direct broken granulation mode of warp of the present invention makes is more open is drenched output in early stage, still all much smaller than the leaching speed of urea; Show that fertilizer of the present invention has tangible slow-releasing.
The preparation of embodiment 4, urea aldehyde organic-inorganic compound fertilizer
In above embodiment 1 in the step 1, when adding the non-metallic minerals sorbent material, add and dry the pig manure of pulverizing after 3kg organism fine powder sorbent material and 3kg become thoroughly decomposed, the fertilizer that the used organism fine powder sorbent material and the back oven dry of becoming thoroughly decomposed are pulverized is all by the 2mm sieve, and the mass ratio of the two is 1:1.Other making method is with embodiment 1, and fertilizer solidifies the back and adopts the granulation of extruding pelletization method, promptly obtains urea aldehyde radical organic-inorganic compound fertilizer.The compound organic and inorganic fertilizer of making through above method proves that through the rape pot experiment fertilizer efficiency period is long, and than common fertilizer nutrient supply abundance, single-dose application can be satisfied the demand of crop whole growing.
Claims (10)
1, a kind of method for preparing urea-formaldehyde fertilizer comprises the steps:
1) starch is mixed with water, gelatinization obtains starch paste; The mass ratio of described starch and described water is starch: water=1:5-20, is preferably 1:5-10;
2) adding urea and formaldehyde in described starch paste, is that 10.5-13, temperature are to react 30-120 minute under 65-80 ℃ the condition in pH value, obtains solution I; The mol ratio of described urea and described formaldehyde is 2-4:1, is preferably 2.45:1; The mass ratio of described urea and described starch is 30-60:1, is preferably 45:1;
Described pH value is preferably 10.5-11, and described temperature is preferably 65-70 ℃, and the time of described reaction is preferably 60-120 minute;
3) add sorbent material and sulphuric acid soln in described solution I, mixing obtains the urea-formaldehyde fertilizer slurry, solidifies to obtain urea-formaldehyde fertilizer.
2, method according to claim 1 is characterized in that: described method comprises the step of granulation; When being 5-40% (quality percentage composition), the water content of the described urea-formaldehyde fertilizer slurry of described granulation in step 3) carries out.
3, method according to claim 1 and 2 is characterized in that: in the described step 3), when described solution I begins to solidify, stop to add described sulphuric acid soln.
4, method according to claim 1 and 2 is characterized in that: described sorbent material is non-metallic minerals powder and/or organism powder; Described non-metallic minerals powder is at least a in zeolite, wilkinite, diatomite and the attapulgite; Described organism powder is at least a in stalk, sawdust and the peat composed of rotten mosses.
5, method according to claim 1 and 2 is characterized in that: the mass ratio of described non-metallic minerals powder and described urea is 1:2-10, is preferably 1:3; The mass ratio of described organism powder and described urea is 1:3-40, is preferably 1:10-40.
6, the urea-formaldehyde fertilizer of arbitrary described method preparation among the claim 1-5, the pH value of this urea-formaldehyde fertilizer is 6.8-7, the insoluble nitrogen content of hot water wherein is smaller or equal to 8% (quality percentage composition).
7, a kind of method for preparing urea-formaldehyde complex fertilizer comprises the steps:
1) starch is mixed with water, gelatinization obtains starch paste; The mass ratio of described starch and described water is starch: water=1:5-20, is preferably 1:5-10;
2) adding urea and formaldehyde in described starch paste, is that 10.5-13, temperature are to react 30-120 minute under 65-80 ℃ the condition in pH value, obtains solution I; The mol ratio of described urea and described formaldehyde is 2-4:1, is preferably 2.45:1; The mass ratio of described urea and described starch is 30-60:1, is preferably 45:1;
Described pH value is preferably 10.5-11, and described temperature is preferably 65-70 ℃, and the time of described reaction is preferably 60-120 minute;
3) add sorbent material in described solution I, add phosphorus potash fertilizer and/or fertilizer and/or middle trace element fertilizer, add sulphuric acid soln, mixing obtains the urea-formaldehyde complex fertilizer slurry, solidifies to obtain urea-formaldehyde complex fertilizer; When described solution I begins to solidify, stop to add described sulphuric acid soln.
8, method according to claim 7 is characterized in that: described method comprises the step of granulation; When being 5-40% (quality percentage composition), the water content of the described urea-formaldehyde complex fertilizer slurry of described granulation in step 3) carries out.
9, according to claim 7 or 8 described methods, it is characterized in that: described sorbent material is non-metallic minerals powder and/or organism powder; Described non-metallic minerals powder is at least a in zeolite, wilkinite, diatomite and the attapulgite; Described organism powder is at least a in stalk, sawdust and the peat composed of rotten mosses.
10, according to claim 7,8 or 9 described methods, it is characterized in that: the mass ratio of described non-metallic minerals powder and described urea is 1:2-10, is preferably 1:3; The mass ratio of described organism powder and described urea is 1:3-40, is preferably 1:10-40.
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