A kind of preparation method of granular compound fertilizer
Technical field
The invention belongs to agricultural slow release fertilizer, relate to the synthetic of fertilizer complete processing and novel material.
Background technology
China is a large agricultural country, and agricultural is the basis of national economy.And the important substance basis that relevant therewith chemical fertilizer industry and water resources are utilized modern agriculture production especially and development.But China's chemical fertilizer utilization ratio only is 30-35% generally for a long time, and low utilization rate of fertilizer has not only caused enormous economic loss, but also can cause serious environmental to be polluted.On the other hand, drought and water shortage also is the important factor of restriction China's agricultural development.Arid and semi-arid area is lack of water throughout the year, and rainwater most ofly ran off or evaporated rainy season, and irrigation water is the often former thereby loss because of evaporation or infiltration etc. also, is not fully utilized.Therefore, the slow release fertilizer technology combined with agricultural water-loss reducer (water-absorbing resin) improve the utilization ratio of chemical fertilizer and water, provide an effective way for addressing this problem.
At present, the slow release fertilizer of development is mainly coating/coated both at home and abroad, and wherein enveloped slow release fertilizer is in fertiliser granulates surface-coated high molecular polymer or inorganic materials.But because the complicated process of preparation of high polymer film-coated type slow release fertilizer, the cost of coated fertilizer is higher, so the actual output of this kind fertilizer is not high.It is core that coated slow releasing fertilizer adopts particle fertilizer such as urea more, and powderies such as phosphate fertilizer fertilizer is sheating material, and by plain disk or drum granulating production, technology is simple, and the fertilizer price is lower, but often slow release effect is not ideal enough.
Water-absorbing resin is a kind of hydrophilic polymer with three-dimensional net structure, and it can absorb a large amount of water within a short period of time, and the moisture of its absorption also can keep under pressurized conditions.Because its premium properties, water-absorbing resin has been successfully applied to agriculture field.Polyacrylate series water-absorbing resin is a topmost in the market series products, but because its refractory organics is easily accumulated in soil after using and caused secondary pollution, has limited its application to a great extent.
Attapulgite clay is a kind of zeopan inorganic mineral material of chain layer structure, and is abundant at China's reserves, cheap, because its unique crystalline structure and performance, the physical properties that can improve the soil can increase its water-retentivity to sandy soil, and soil can increase its water-permeable to hardening.Secondly,, use so itself can be used as fertilizer owing to itself contain the required various nutrient elements K of crop, P, Ca, Mg, Fe, Mn etc., and then the performance fertilizer efficiency.In addition, because attapulgite clay has one dimension Nano structure, surface-area is very big, and adsorptive power is very strong.With after fertilizer mixes, fertilizer nutrient is slowly discharged it, improve fertilizer efficiency, reduce the loss of available fertilizer.Chinese patent literature CN 1380374A directly mixes as fertilizer sources with attapulgite with urea.But conventional components such as this fertilizer is not phosphorous, potassium, fertility is limited, and is not particle fertilizer, uses also to be subjected to bigger restriction.
Summary of the invention
In view of above-mentioned, the advantage that the present invention is intended to comprehensive inorganic mineral material, natural product and some hydrophilic high molecular polymers prepares a kind of particulate state multilayer coated compound fertilizer and improves granulation of fertilizer technology.This particulate state fertilizer comprises the required various nutrient elements of plant.Simultaneously, the multilayer coating by attapulgite clay, sodium alginate and water-absorbing resin make it to have water-absorbing-retaining, multiple function such as slowly-releasing, soil conditioning.
For achieving the above object, the present invention takes following technical scheme:
A. in granulating disc, put into the urea granules that diameter is 1-2mm, spray into atomized water with the urea granules moistened surface after, the attapulgite clay, urea and the potassium primary phosphate powder that mix are partly added in the disk, and rotary disk is wrapped in the urea granules surface with mix powder; With atomized water that particle surface is wetting once more, and add mix powder, it is wrapped in particle surface; Like this repeated multiple times is wrapped in the urea granules skin with the mix powder of whole attapulgite clay, urea and potassium primary phosphate, obtains the fertilizer kernel.
B. sodium alginate powder is joined in the granulating disc, rotary disk makes sodium alginate be wrapped in fertilizer kernel skin, and spraying into concentration, to be that 5% calcium chloride water carries out sodium alginate crosslinked, the sodium alginate as fertilizer sources internal layer coating after crosslinked.
C. water-absorbent resin powder is joined in the granulating disc, rotary disk makes water-absorbent resin powder be wrapped in the fertiliser granulates skin, the outer coating of as fertilizer sources.
D.. after the fertiliser granulates drying that coating is finished, obtain the granulated fertilizer that particle diameter is 2.5-3.5mm, be finished product.
The finished product outward appearance is black, and ultimate compression strength is 21.6-28.4N.
The present invention compares with domestic and international other composite fertilizer, and its outstanding feature is:
1. attapulgite clay can effectively improve the fertilizer granulating rate as the binding agent in the granulation process; Attapulgite clay itself contains the required various nutrient elements K of plant, P, Ca, Mg, Fe, Mn etc., can improve fertilizer efficiency; Because the porous crystal structure of Attapulgite can carry out active adsorption to fertilizer, thereby slow down the release of nutritive element.
2. institute's synthetic water-absorbing resin has certain degradation property, and the water absorbent rate height, and it is heavy 200 times for self that normal pressure can be inhaled down tap water.The adding of humic acids had both improved the water-retaining capacity of water-absorbing resin, can be used as a kind of fertilizer again and slowly discharged.The adding of sodium alginate has improved the degradation property of this water-absorbing resin.Measure water-absorbing resin use before and after the variation of soil pH value, the result shows, this water-absorbing resin can be with pH value the soil of 3-10 effectively to be adjusted to the pH value be about 6.5, show that this water-absorbing resin can be used as a kind of soil conditioner.This owing to contain in this water-absorbing resin structure a large amount of-COOH and-COO
-Group ,-COOH can with the OH in the alkaline soil
-Reaction ,-COO
-Can with the H in the acid soil
+Reaction, thus play shock absorption.
3. the elemental analyser measurement result shows, nitrogen phosphorus potassium total content is about 30% in this fertilizer sample, and slow-release time can reach more than one month.
4. this product physical strength height, deliquescence does not transport and uses conveniently.
Description of drawings
Fig. 1 is a main technique schematic flow sheet of the present invention.
Fig. 2 is the release profiles of nitrogen (a), potassium (b), phosphorus (c) in 20% the soil for the fertilizer sample of example 1 under the room temperature in soil humidity.
Embodiment
Below, again technical scheme of the present invention being further described by embodiment, the umber of embodiment is parts by weight.
Embodiment 1:
A. the preparation of water-absorbing resin
3 parts of sodium alginates are joined in the reactor, after adding 200 parts of dissolved in distilled water, add 26.7 parts of vinylformic acid, adding 10.4 parts of sodium hydroxide again neutralizes, add 13.3 parts of acrylamides, 4 parts of humic acidss, 0.4 part of ammonium persulphate, 0.024 part of N then successively, N '-methylene-bisacrylamide is after stirring, be warming up to 75 ℃, reacted 3 hours.After reacting end,, cross 110 mesh sieves, get water-absorbing resin product oven dry, pulverizing, standby.
B. the preparation of granular compound fertilizer
I. 70 parts of attapulgite clay, 50 parts of urea and 50 parts of potassium primary phosphates are pulverized, crossed 150 mesh sieves, mix.
Ii. (institute is built in the Yingyang City, Henan Province at granulating disc, model LZ25) the lining urea granules that to put into 30 parts of diameters be 1-2mm, spray into atomized water with the urea granules moistened surface after, partly add the attapulgite clay, urea and the potassium primary phosphate powder that mix in the disk, rotary disk is wrapped in the urea granules surface with mix powder; It is wetting with particle surface to spray into atomized water once more, and adds mix powder, and it is wrapped in particle surface; 8 times so repeatedly, the mix powder of whole attapulgite clay, urea and potassium primary phosphate is wrapped in the urea granules skin, obtain the fertilizer kernel.
Iii. the sodium alginate powder with 10 parts of mistake 110 mesh sieves joins the coating that rolls in the granulating disc; make sodium alginate be wrapped in fertilizer kernel skin; and spray into concentration and be 5% calcium chloride water sodium alginate is carried out crosslinked, the sodium alginate as fertilizer sources internal layer coating after crosslinked.
Iv. at last 15 parts of water-absorbent resin powders that prepare are joined the coating that rolls in the disk, make water-absorbent resin powder be wrapped in the fertiliser granulates skin, the outer coating of as fertilizer sources.Room temperature is dried then, and promptly obtaining particle diameter is the granulated fertilizer finished product of 2.5-3.5mm.
The content of granulated fertilizer finished product internal layer coating sodium alginate is 6%, and the consumption of calcium chloride water is 12% of a sodium alginate consumption, and the content of outer coating water-absorbing resin is 11%.Ultimate compression strength is 26.5N.
What Fig. 2 showed is that this sample is 20% in soil humidity, the slow release effect curve under the room temperature condition.As shown in the figure, in the sample release of nitrogen very fast, discharging percentage ratio in 5 days is 92.6%.This is because the solubleness of urea is bigger, and is difficult for adsorbed by charged water-absorbing resin and attapulgite clay as a kind of neutral organic molecule.But compare (discharge in 12 hours and surpass 98%) with the common urea particle, the slow-releasing of nitrogen still has certain improvement in this sample.The release of phosphorus and potassium is slower, has discharged 81% and 91% in 30 days respectively, has effectively prolonged the release period of fertilizer, more helps the absorption of crop.
Embodiment 2: the working condition of water-absorbing resin is with embodiment 1.60 parts of attapulgite clay, 60 parts of urea and 70 parts of potassium primary phosphates are pulverized, cross 150 mesh sieves, branch joins for 9 times and is placed with 40 parts of particle diameters in the disk of the granular urea that is 1-2mm after mixing, and wraps up under the effect of atomized water, makes the powder wrapped that mixes on the granular urea surface.Then, join the coating that rolls in the disk, spray into 5% calcium chloride water after coating is finished the sodium alginate powder of 15 parts of mistake 110 mesh sieves.With 20 parts of water-absorbent resin powders that prepare, cross 110 mesh sieves at last, add the coating that rolls in the disk, dry, promptly obtaining particle diameter is the granulated fertilizer finished product of 2.5-3.5mm.The content of this finished product internal layer coating sodium alginate is 9%, and the consumption of calcium chloride water is 14% of a sodium alginate consumption, and the content of outer coating water-absorbing resin is 13%.Sample ultimate compression strength is 24.5N.