A press for making microporous needle-shaped fertilizer

Abstract

The present application relates to a kind of press for preparing microporous needle-shaped fertilizer, the press includes cylinder and the double screw rod arranged in the cylinder;The side of the cylinder is provided with feed inlet, bottom is provided with aperture plate;The double screw rod includes first screw and second screw, which are arranged side by side and the rotation direction is opposite, the thread of the first screw and the thread of the second screw are engaged with each other, one end of the double screw rod close to the feed inlet is connected with driving mechanism, the end of the first screw and the second screw close to the aperture plate is respectively equipped with 2-6 stirring paddles.The microporous needle-shaped fertilizer prepared by the press of the present application has faster dissolution speed, and the solution after dissolution has low viscosity and low turbidity, which can be better applied to large-area drip irrigation system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fertilizer production, in particular to a press for preparing microporous needle-shaped fertilizer. BACKGROUND

[0002] CN110526761A discloses a kind of granular fertilizer dry production process, which includes the following steps: the raw material of granular fertilizer containing starch or polyethylene glycol is crushed, mixed and stirred, to obtain dry powder material with water mass 1.5%~3%; The dry powder material is introduced into a double-screw extruder, so that the dry powder material is extruded at an environment of 65~70℃ to extrude continuous long strip fertilizer with water mass less than 2%; The continuous long strip fertilizer is dried and cooled, and granulated to obtain granular fertilizer.

[0003] However, the existing method for preparing granular fertilizer still has the problem of slow dissolution speed. SUMMARY

[0004] The present application aims to overcome the above-mentioned defects of existing granular fertilizer, and provide a press for preparing microporous needle-shaped fertilizer with faster dissolution speed.

[0005] To achieve the above-mentioned purpose, the present application provides a press for preparing microporous needle-shaped fertilizer, which comprises a cylinder 1 and a double screw arranged in the cylinder 1, the side of the cylinder 1 is provided with a feeding port 5, and the bottom is provided with a hole plate 6; The double screw comprises a first screw 21 and a second screw 22 arranged side by side and rotating in opposite directions, the threads of the first screw 21 and the threads of the second screw 22 are engaged with each other, one end of the double screw close to the feeding port 5 is connected with a driving mechanism, and the ends of the first screw 21 and the second screw 22 close to the hole plate 6 are respectively equipped with 2-6 stirring paddles 9; The driving mechanism comprises a driving motor 4 connected to the first screw 21 and a gear set 12 connected between the first screw 21 and the second screw 22; The gear set 12 comprises a first gear 121 and a second gear 122, the first gear 121 is fixed on the first screw 21, the second gear 122 is fixed on the second screw 22, and the first gear 121 and the second gear 122 are engaged with each other; The driving motor 4 is drivingly connected to the first screw 21 through a speed reducer 41; The first screw 21 and the second screw 22 can rotate in opposite directions at the same speed.

[0006] Optionally, the diameters of the first screw 21 and the second screw 22 are 20-50 cm respectively, and the lengths are 40-100 cm respectively; The center distance between the first screw 21 and the second screw 22 is 20-50 cm.

[0007] Optionally, the screw channel depth of the first screw 21 and the second screw 22 is 5-10 cm, the screw rib width is 1-5 cm, and the thread rise angle is 2-10°.

[0008] Optionally, the length of the stirring paddle 9 is 5-22 cm, the width is 1-5 cm, and the thickness is 0.5-3 cm, the inner ends of the plurality of stirring paddles 9 surround to form a gap area 10, the diameter of the gap area 10 is 2-10 cm, and the distance between the inner ends of two adjacent stirring paddles 9 is 2-10 cm; the stirring paddle 9 comprises a first stirring paddle 91 and a second stirring paddle 92, the first stirring paddle 91 and the second stirring paddle 92 can rotate on the same plane, and the outer end of the first stirring paddle 91 extends into between two adjacent second stirring paddles 92.

[0009] Optionally, the thickness of the barrel 1 is 1-5 cm; the inner wall of the barrel 1 is further provided with an internal thread 11, the depth of the internal thread 11 is 1-8 mm, the width is 1-5 mm, and the thread rise angle is 1-15°.

[0010] Optionally, the distance between the screw rib of the first screw 21 and the second screw 22 and the inner surface of the barrel 1 is 0.1-5 mm.

[0011] Optionally, the thickness of the hole plate 6 is 0.5-2 cm, the hole plate 6 is provided with a hole 61, the hole diameter of the hole 61 is 1-3 mm, and the hole spacing is 2-10 mm.

[0012] Optionally, the distance between the stirring paddle 9 and the hole plate 6 is 1-5 mm.

[0013] Optionally, the middle of the hole plate 6 is provided with a non-hole belt 62, the non-hole belt 62 comprises a first area 63, a second area 64 and a third area 65 connected in sequence, the first area 63 and the third area 65 are rectangular, the length is 4-14 cm, and the width is 1-4 cm; the second area 64 is circular, and the diameter is 2-5 cm.

[0014] Optionally, the tail of the corresponding barrel 1 part of the stirring paddle 9 is provided with a cooling jacket 7, and the cooling jacket 7 is connected with a cooling water pipe 8.

[0015] Through the above technical scheme, the microporous needle-shaped fertilizer prepared by the press machine has a faster dissolution speed and can be better applied to a large-area drip irrigation system.

[0016] Other features and advantages of the present application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of the specification, illustrate embodiments of the application and are used to explain the application, but are not intended to limit the application. In the drawings:

[0018] Figure 1 is a schematic diagram of the structure of the press of the present application;

[0019] Figure 2 is a schematic diagram of the structure of the double screw and gear set of the present application;

[0020] Figure 3 is a schematic diagram of the structure of the upper part of the double screw of the present application;

[0021] Figure 4 is a schematic diagram of the structure of the barrel of the present application;

[0022] Figure 5 is a schematic diagram of the structure of the perforated plate of the present application.

[0023] Explanation of reference signs

[0024] 1 - barrel; 11 - internal thread; 12 - gear set; 121 - first gear; 122 - second gear; 123 - gear box; 2 - drive rod; 21 - first screw; 22 - second screw; 4 - drive motor; 41 - speed reducer; 5 - feed inlet; 6 - perforated plate; 61 - hole; 62 - non-perforated band; 63 - first zone; 64 - second zone; 65 - third zone; 7 - cooling jacket; 8 - cooling water pipe; 9 - stirring paddle; 91 - first stirring paddle; 92 - second stirring paddle; 10 - gap zone. DETAILED DESCRIPTION

[0025] The specific embodiments of the present application are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the present application.

[0026] The present application is unexpectedly found that under the conditions of proper pressure and shear and kneading, the powder fertilizer premix without using binder and / or filler can be converted into slurry material with proper viscosity, and the gas entrained in the fertilizer premix can be uniformly dispersed into the slurry material with proper viscosity to form micro-bubbles, which can further form micropores after extrusion, thus obtaining the microporous needle-shaped fertilizer, and thus obtaining the present application. The microporous needle-shaped fertilizer of the present application can be prepared by extrusion granulation without using binder and / or filler, thus avoiding the adverse effects of binder and / or filler on dissolution rate and turbidity after dissolution; and the microporous needle-shaped fertilizer of the present application can further significantly improve the dissolution rate and achieve instantaneous dissolution due to the micropores.

[0027] The application provides a press machine for preparing microporous needle-shaped fertilizer, referring to Figures 1-3 The press machine comprises a barrel 1 and double screws arranged in the barrel 1, a feeding port 5 is arranged on the side of the barrel 1, and a hole plate 6 is arranged on the bottom of the barrel 1; the double screws comprise a first screw 21 and a second screw 22 arranged side by side and rotating in opposite directions, the thread of the first screw 21 and the thread of the second screw 22 are engaged with each other, one end of the double screws close to the feeding port 5 is connected with a driving mechanism, and the driving mechanism is located at the upper end of the barrel 1; the end of the first screw 21 and the end of the second screw 22 close to the hole plate 6 are respectively equipped with 2-6 stirring paddles 9; the driving motor 4 is in driving connection with the first screw 21 through a speed reducer 41; and the first screw 21 and the second screw 22 can rotate in opposite directions at the same rotating speed.

[0028] In the press machine, the first screw 21 and the second screw 22 are arranged side by side and rotate in opposite directions, the thread of the first screw 21 and the thread of the second screw 22 are engaged with each other, and the first screw 21 and the second screw 22 can extrude and first shear the fertilizer premix and the air entrained by the fertilizer premix, so that the material starts to soften and co-melt into slurry material under the action of extrusion, shearing and other mechanical forces. In the press machine, the stirring paddles 9 can second shear and knead the material after extrusion and first shearing, further improve the shearing force, so that the material is fully mixed and uniform and the slurry material containing micro-bubbles is obtained. More specifically, by adding the stirring paddles 9 at the ends of the double screws, the shearing force is greatly increased, on the one hand, the raw material becomes slurry material, and on the other hand, the entrained gas is uniformly mixed into the slurry material in the form of micro-bubbles, the slurry material containing micro-bubbles forms a line after passing through the hole plate 6, and the micro-bubbles expand to form pores during the hardening process, and the line is segmented to obtain microporous needle-shaped fertilizer. In the application, due to the existence of micropores, the dissolution speed of the microporous needle-shaped fertilizer is greatly improved; and the raw material without adding a binder or a filler can be prepared into microporous needle-shaped fertilizer, so that the viscosity and turbidity of the microporous needle-shaped fertilizer after dissolution are significantly reduced.

[0029] According to the application, the driving mechanism comprises a driving motor 4 connected to the first screw 21 and a gear set 12 connected between the first screw 21 and the second screw 22. Figure 2 The first gear 121 of the two gears is fixed on the first screw 21 and can rotate coaxially with the first screw 21, Figure 2A second gear 122 of the two gears is fixed on the second screw 22 and can rotate coaxially with the second screw 22, and the first gear 121 is engaged with the second gear 122. The driving motor 4 can be connected with the first screw 21 through a suitable reducer 41. The first screw 21 and the second screw 22 can rotate reversely at the same speed. The reducer 41 and the upper end of the first screw 21 can be connected through a driving rod 2. The gear set 12 can be contained in a gear box 123.

[0030] According to the present application, the threads of the first screw 21 and the second screw 22 are arranged alternately and engaged with each other.

[0031] According to the present application, as a preferred embodiment, the diameters of the first screw 21 and the second screw 22 are 20-50 cm respectively, and the lengths are 40-100 cm respectively; and the center distance between the first screw 21 and the second screw 22 is 20-50 cm. In this preferred embodiment, the first screw 21 and the second screw 22 can provide sufficient and appropriate pressure and shear force. The length direction of the first screw 21 and the second screw 22 refers to the direction of the rotating shaft.

[0032] According to the present application, as a preferred embodiment, the thread groove depth of the first screw 21 and the second screw 22 is 5-10 cm respectively, the thread width is 1-5 cm respectively, and the thread angle is 2-10° respectively. In the direction from outside to inside of the cylinder 1, the thread is inclined downward. In this preferred embodiment, the energy consumption and the wear rate of the press can be reduced.

[0033] According to the present application, the number of the plurality of stirring paddles 9 can be 2, 3, 4, 5 or 6, and the plurality of stirring paddles 9 can be arranged uniformly and symmetrically at the end of the first screw 21 and the second screw 22 close to the hole plate 6; optionally, the length of the stirring paddle 9 is 5-22 cm, the width is 1-5 cm, and the thickness is 0.5-3 cm, and the inner ends of the plurality of stirring paddles 9 surround a gap area 10, the diameter of the gap area 10 is 2-10 cm, and the distance between the inner ends of two adjacent stirring paddles 9 is 2-10 cm; the stirring paddle 9 includes a first stirring paddle 91 and a second stirring paddle 92, the first stirring paddle 91 and the second stirring paddle 92 can rotate on the same plane, and the outer end of the first stirring paddle 91 extends into the space between two adjacent second stirring paddles 92. The gap area 10 allows the material to flow, which is beneficial to enhance the effect of shearing and kneading. The length direction of the stirring paddle 9 refers to the radial direction of the screw.

[0034] According to the application, optionally, as shown in Figure 4 The thickness of the barrel 1 is 1-5 cm; the inner wall of the barrel 1 is further provided with an internal thread 11, the depth of the internal thread 11 is 1-8 mm, the width is 1-5 mm, and the thread rise angle is 1-15°. The internal thread 11 of the barrel inner wall can further increase the shearing and kneading of the material, so that the material realizes co-melting.

[0035] According to the application, optionally, the distance between the screw flight of the first screw 21 and the second screw 22 and the inner surface of the barrel 1 is 0.1-5 mm. Through the above-mentioned implementation, it is beneficial to the heat conduction of the mechanical heat generated by the first screw 21 and the second screw 22 and the increase of the shearing force, so as to obtain the slurry material, while reducing the return flow of the slurry material.

[0036] According to the application, optionally, as shown in Figure 5 The thickness of the hole plate 6 is 0.5-2 cm, and the hole plate 6 is provided with a hole 61, the hole diameter of the hole 61 is 1-3 mm, and the hole spacing is 2-10 mm. Through the above-mentioned implementation, it is beneficial to the extrusion of the slurry material containing micro-bubbles through the hole plate 6. The slurry material containing micro-bubbles after extrusion through the hole plate 6 can be formed into microporous needle-shaped fertilizer by cutting and granulating.

[0037] According to the application, optionally, the distance between the stirring paddle 9 and the hole plate 6 is 1-5 mm; the middle of the hole plate 6 is provided with a non-hole belt 62, the non-hole belt 62 includes a first area 63, a second area 64 and a third area 65 connected in sequence, the first area 63 and the third area 65 are rectangular respectively, the length is 4-14 cm, and the width is 1-4 cm; the second area 64 is circular, and the diameter is 2-5 cm. The stirring paddle 9 and the hole plate 6 have a certain distance, forming a space, which is beneficial to the cooperation of the non-hole belt 62 of the hole plate 6 and the stirring paddle 9, so that the density of the extruded slurry material containing micro-bubbles fluctuates periodically, so that the extruded slurry material containing micro-bubbles can be naturally and uniformly broken and hardened into microporous needle-shaped fertilizer, and cutting and granulation can not be used.

[0038] According to the application, optionally, the tail of the corresponding barrel 1 part of the stirring paddle 9 is provided with a cooling jacket 7, and the cooling jacket 7 is connected with a cooling water pipe 8. The cooling jacket 7 can control the temperature of the material during the second shearing and kneading, avoid the decomposition of part of the material due to high temperature, and is beneficial to the stable distribution of micro-bubbles in the slurry material.

[0039] In the preferred embodiment of the present application, the diameters of the first screw 21 and the second screw 22 are preferably 25-40 cm, further preferably 30 cm, and the lengths of the first screw 21 and the second screw 22 are preferably 45-90 cm, further preferably 50 cm; the center distance between the first screw 21 and the second screw 22 is preferably 25-40 cm, further preferably 30 cm. The channel depths of the first screw 21 and the second screw 22 are preferably 6-8 cm, further preferably 7 cm, the flight widths are preferably 2-5 cm, further preferably 3 cm, and the thread angles are preferably 3-9°, further preferably 5°.

[0040] In the preferred embodiment of the present application, the length of the stirring paddle 9 is preferably 8-15 cm, further preferably 10 cm, the width is preferably 2-4 cm, further preferably 3 cm, the thickness is preferably 1-2 cm, further preferably 1.5 cm, and the diameter of the gap region 10 is preferably 3-9 cm, further preferably 5 cm.

[0041] In the preferred embodiment of the present application, the thickness of the barrel 1 is preferably 2-4 cm, further preferably 3 cm; the depth of the internal thread 11 provided on the inner wall of the barrel 1 is preferably 2-7 mm, further preferably 5 mm, the width is preferably 2-4 mm, further preferably 3 mm, the thread angle is preferably 2-12°, further preferably 5°, and the distance between the flights of the first screw 21 and the second screw 22 and the inner surface of the barrel 1 is preferably 0.2-4 mm, further preferably 0.3 mm.

[0042] In the preferred embodiment of the present application, the thickness of the perforated plate 6 is preferably 0.8-1.5 cm, further preferably 1 cm, the hole diameter of the holes 61 provided on the perforated plate 6 is preferably 1.5-2.5 mm, further preferably 2 mm, the hole spacing is preferably 5-8 mm, further preferably 6 mm, the distance between the stirring paddle 9 and the perforated plate 6 is preferably 2-4 mm, further preferably 3 mm, the rectangular length of the non-perforated band 62 provided in the middle of the perforated plate 6 is preferably 6-10 cm, further preferably 8 cm, the width is preferably 1-3 cm, further preferably 2 cm, and the diameter of the circle is preferably 2.5-4 cm, further preferably 3 cm.

[0043] The press machine of the present application is suitable for a method for preparing microporous needle-shaped fertilizer. The method can use a suitable press machine to granulate the fertilizer, preferably, the method uses the press machine provided by the present application to granulate the fertilizer, which comprises: feeding the fertilizer premix to be granulated into the feed inlet 5 of the press machine, using a double screw to extrude and first shear the fertilizer premix and the gas entrained by the fertilizer premix, and using the stirring paddle 9 to second shear and knead the material after extrusion and first shearing to obtain slurry material containing micro-bubbles, and then extruding the slurry material containing micro-bubbles through the hole plate 6.

[0044] Through extrusion and first shearing, the powdered fertilizer premix can be converted into slurry material with suitable viscosity, and through second shearing and kneading, the gas entrained in the fertilizer premix can be uniformly dispersed into the slurry material with suitable viscosity to form micro-bubbles, which can further form micropores after extrusion, thus obtaining microporous needle-shaped fertilizer, thereby obtaining the present application. The microporous needle-shaped fertilizer of the present application can further significantly improve the dissolution speed due to the micropores, and can achieve instantaneous dissolution.

[0045] The powdered fertilizer premix can contain or not contain a binder and / or a filler, and particularly preferably, the powdered fertilizer premix does not contain a binder and / or a filler, which can avoid the adverse effects of the binder and / or the filler on the dissolution speed and the turbidity after dissolution, while also increasing the content of effective nutrient ingredients in the fertilizer product after extrusion and granulation, and reducing the cost of purchasing raw materials and transportation and storage.

[0046] The present application can improve the shearing force by extruding and first shearing the fertilizer premix and the gas entrained by the fertilizer premix with a double screw, and second shearing and kneading the material after extrusion and first shearing with the stirring paddle 9, so that the viscosity of the premix is reduced, and the gas entrained by the premix becomes micro-bubbles with pressure mixed into the slurry premix to obtain slurry material containing micro-bubbles, which is naturally cooled after extrusion through the hole plate 6, and the micro-bubbles in it expand to form micropores naturally, and the extruded linear slurry naturally breaks and hardens to form microporous needle-shaped fertilizer.

[0047] According to the present application, the extrusion pressure is 5-50 MPa, the shearing force of the first shearing and the second shearing is 30-300 kN respectively, and the weight of the slurry material containing micro-bubbles extruded through the hole plate 6 per minute is 5-20 kg. In the present application, the pressure and the shearing force are the maximum values in the press machine, which can be achieved by adjusting the structure and operating parameters of the press machine. In the present application, the pressure can be measured by a pressure probe, and the shearing force can be calculated by the motor power and the shearing linear speed.

[0048] According to the application, the rotating speed of the double screw is 10-100 rpm, preferably 40-80 rpm, and more preferably 50-70 rpm.

[0049] According to the application, the temperature of the material after extrusion and first shearing is 70-150 DEG C, and the temperature of the slurry material containing micro-bubbles is 50-120 DEG C.

[0050] According to the application, in order to further facilitate the pore forming of the micro-pores, as a preferred embodiment, the moisture content of the fertilizer premix is 0.5-3 wt%, and the bulk density is 0.8-1.5 g / cm3. In this preferred embodiment, the gas entrained in the fertilizer premix is in a suitable range, which is beneficial to the pore forming of the micro-pores and the breaking and forming of the micro-porous needle-shaped fertilizer.

[0051] According to the application, the composition of the fertilizer premix is not particularly required, and can be an existing composition or a mature composition, or a new composition in the future. Optionally, the fertilizer premix comprises at least one of nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, calcium fertilizer, magnesium fertilizer, sulfur fertilizer, boron fertilizer, manganese fertilizer, iron fertilizer, zinc fertilizer, copper fertilizer, molybdenum fertilizer and chlorine fertilizer.

[0052] Preferably, the fertilizer premix is a nitrogen-phosphorus-potassium compound fertilizer premix, and the content of the phosphorus fertilizer is 5-65 wt% relative to 20-80 wt% of the nitrogen fertilizer, and the content of the potassium fertilizer is 10-50 wt%.

[0053] According to the application, the raw materials are optionally crushed, and then are optionally screened through a screen with a pore size of 0.5-1.5 mm, and then are fed into a mixer for stirring and mixing uniformly to obtain the fertilizer premix.

[0054] According to the application, the nitrogen fertilizer comprises one or more of ammonium nitrate, ammonium phosphate, urea, ammonium chloride, ammonium sulfate, ammonium bicarbonate, monoammonium phosphate, diammonium phosphate and ammonium polyphosphate.

[0055] According to the application, the phosphorus fertilizer comprises one or more of ammonium phosphate, diammonium phosphate, nitrate phosphate, superphosphate, double superphosphate, calcium-magnesium phosphate and ammonium polyphosphate.

[0056] According to the application, the potassium fertilizer comprises one or more of potassium chloride, potassium sulfate, potassium-magnesium sulfate and potassium nitrate.

[0057] The application obtains a micro-porous needle-shaped fertilizer, which has a diameter of 1.2-3 mm and a length of 2-15 mm, and the micro-pores have a pore size of 0.1-50 μm and a porosity of 7-25%.

[0058] According to the present application, the water content of the microporous needle-shaped fertilizer is 0.1-1% by weight, and the bulk density is 0.6-1.1 g / cm3.

[0059] According to the present application, the viscosity of a 10% by weight aqueous solution of the dissolved microporous needle-shaped fertilizer is 1-10 centipoise, and the turbidity is 2-100 NTU.

[0060] The microporous needle-shaped fertilizer can contain at least one of nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, calcium fertilizer, magnesium fertilizer, sulfur fertilizer, boron fertilizer, manganese fertilizer, iron fertilizer, zinc fertilizer, copper fertilizer, molybdenum fertilizer and chlorine fertilizer.

[0061] Preferably, the microporous needle-shaped fertilizer is a nitrogen-phosphorus-potassium compound microporous needle-shaped fertilizer, wherein the content of the phosphorus fertilizer is 5-65 parts by weight, and the content of the potassium fertilizer is 10-50 parts by weight, relative to 20-80 parts by weight of the nitrogen fertilizer.

[0062] Preferably, the microporous needle-shaped fertilizer is prepared by the above method.

[0063] The microporous needle-shaped fertilizer of the present application has a faster dissolution rate, and the solution after dissolution has low viscosity and low turbidity, and can be better applied to large-area drip irrigation systems.

[0064] The present application will be further illustrated by the following examples, but the present application is not limited in any way by the examples.

[0065] The diameters of the first screw 21 and the second screw 22 of the press machine used in the present application are 30 cm, and the lengths are 50 cm; the center distance of the first screw 21 and the second screw 22 is 30 cm. The screw groove depths of the first screw 21 and the second screw 22 are 3 cm, the screw rib widths are 4 cm, and the thread angles are 5°. The lengths of the first stirring paddle 91 and the second stirring paddle 92 are 10 cm, and the width and thickness are 3 cm and 1.5 cm, respectively. The diameter of the gap region 10 is 5 cm. The thickness of the cylinder 1 is 3 cm, and the distances between the screw ribs of the first screw 21 and the second screw 22 and the inner surface of the cylinder 1 are 0.3 mm. The thickness of the perforated plate 6 is 1 cm, the hole diameter of the hole 61 is 1.1 mm, and the hole spacing is 6 mm.

[0066] Example 1

[0067] In this example, a microporous needle-shaped fertilizer is prepared, and the specific method comprises the following steps:

[0068] The fertilizer premix comprises, by mass percentage, urea 15.6%, monoammonium phosphate 36.5%, ammonium chloride 20.8%, and potassium chloride 27.1%.

[0069] The fertilizer premix to be granulated is fed into the feed inlet 5 of the press, the driving motor 4 drives the first screw 21 and the second screw 22 to rotate reversely in the barrel 1, the fertilizer premix and the air entrained by the fertilizer premix are extruded and first sheared, and the extruded and first sheared material is second sheared and kneaded by the first stirring paddle 91 and the second stirring paddle 92, while the material temperature is controlled by the cooling jacket 7, to obtain a slurry material containing micro-bubbles, then the slurry material containing micro-bubbles is extruded through the holes 61 on the hole plate 6, and the extruded slurry material containing micro-bubbles is naturally cooled, the micro-bubbles therein expand and naturally form micro-holes, the extruded linear slurry material naturally breaks and hardens to form the micro-hole needle-shaped fertilizer.

[0070] The extrusion pressure is 40 MPa, the shearing force of the first shearing and the second shearing is 200 kN respectively, the weight of the slurry material containing micro-bubbles extruded through the hole plate per minute is 18 kg, the rotating speed of the first screw and the second screw is 60 rpm, the temperature of the extruded and first sheared material is 90℃, and the temperature of the slurry material containing micro-bubbles is 80℃.

[0071] The micro-hole needle-shaped fertilizer obtained in this embodiment has a diameter of 1.4-1.6 mm and a length of 8-12 mm.

[0072] Example 2

[0073] This embodiment prepares a micro-hole needle-shaped fertilizer, and the specific method comprises the following steps:

[0074] The fertilizer premix comprises, by mass percentage, urea 62.0%, monoammonium phosphate 15.0%, and potassium chloride 23.0%.

[0075] The fertilizer premix to be granulated is fed into the feed inlet 5 of the press, the driving motor 4 drives the first screw 21 and the second screw 22 to rotate reversely in the barrel 1, the fertilizer premix and the air entrained by the fertilizer premix are extruded and first sheared, and the extruded and first sheared material is second sheared and kneaded by the first stirring paddle 91 and the second stirring paddle 92, while the material temperature is controlled by the cooling jacket 7, to obtain a slurry material containing micro-bubbles, then the slurry material containing micro-bubbles is extruded through the holes 61 on the hole plate 6, and the extruded slurry material containing micro-bubbles is naturally cooled, the micro-bubbles therein expand and naturally form micro-holes, the extruded linear slurry material naturally breaks and hardens to form the micro-hole needle-shaped fertilizer.

[0076] The extrusion pressure is 30 MPa, the shear force of the first shear and the second shear is 150 kN respectively, the weight of the slurry material containing micro-bubbles extruded through the hole plate per minute is 15 kg, the rotating speed of the first screw and the second screw is 50 rpm, the temperature of the material after extrusion and the first shear is 80℃, and the temperature of the slurry material containing micro-bubbles is 70℃.

[0077] The diameter of the micro-porous needle-shaped fertilizer obtained in the embodiment is 1.2-1.4 mm, and the length is 10-15 mm.

[0078] Embodiment 3

[0079] The embodiment prepares a micro-porous needle-shaped fertilizer, and the specific method comprises the following steps:

[0080] The fertilizer premix comprises, by mass percentage, 22.4% of ammonium nitrate phosphate, 32.2% of monoammonium phosphate, 2.0% of ammonium sulfate, and 43.4% of potassium sulfate.

[0081] The fertilizer premix to be granulated is sent into the feeding port 5 of the press, the driving motor 4 drives the first screw 21 and the second screw 22 to rotate reversely in the barrel 1, the fertilizer premix and the air entrained by the fertilizer premix are subjected to extrusion and the first shear, and the first stirring paddle 91 and the second stirring paddle 92 are used to perform the second shear and the kneading on the material after the extrusion and the first shear, while the temperature of the material is controlled by the cooling jacket 7 to obtain the slurry material containing micro-bubbles, then the slurry material containing micro-bubbles is extruded through the hole 61 (hole diameter 2 mm) on the hole plate 6, and the extruded slurry material containing micro-bubbles is naturally cooled, the micro-bubbles in the slurry material expand, and the micro-pores are naturally formed, the extruded linear slurry material is naturally broken and hardened to form the micro-porous needle-shaped fertilizer.

[0082] The extrusion pressure is 50 MPa, the shear force of the first shear and the second shear is 300 kN respectively, the weight of the slurry material containing micro-bubbles extruded through the hole plate per minute is 20 kg, the rotating speed of the first screw and the second screw is 100 rpm, the temperature of the material after extrusion and the first shear is 130℃, and the temperature of the slurry material containing micro-bubbles is 100℃.

[0083] The diameter of the micro-porous needle-shaped fertilizer obtained in the embodiment is 2.3-2.5 mm, and the length is 6-10 mm.

[0084] Embodiment 4

[0085] The embodiment prepares a micro-porous needle-shaped fertilizer, and the specific method comprises the following steps:

[0086] The fertilizer premix comprises, by mass percentage, 44.1% of urea, 10.2% of potassium sulfate, 38.9% of ammonium sulfate, 6.7% of potassium chloride, and 0.1% of ammonium bicarbonate.

[0087] The fertilizer premix to be granulated is fed into the feed inlet 5 of the press, the driving motor 4 drives the first screw 21 and drives the second screw 22 to rotate reversely in the barrel 1, the fertilizer premix and the air entrained by the fertilizer premix are extruded and first sheared, and the extruded and first sheared material is second sheared and kneaded by the first stirring paddle 91 and the second stirring paddle 92, while the temperature of the material is controlled by the cooling jacket 7, to obtain a slurry material containing micro-bubbles, then the slurry material containing micro-bubbles is extruded through the holes 61 on the hole plate 6, and the extruded slurry material containing micro-bubbles is naturally cooled, the micro-bubbles in the slurry material expand, and the micro-holes are naturally formed, the extruded linear slurry material is naturally broken and hardened to form the micro-porous needle-shaped fertilizer material.

[0088] The extrusion pressure is 30 MPa, the shearing force of the first shearing and the second shearing is 150 kN respectively, the weight of the slurry material containing micro-bubbles extruded through the hole plate per minute is 10 kg, the rotating speed of the first screw and the second screw is 40 rpm, the temperature of the extruded and first sheared material is 70℃, and the temperature of the slurry material containing micro-bubbles is 60℃.

[0089] The diameter of the micro-porous needle-shaped fertilizer obtained in the example is 1.2-1.3 mm, and the length is 5-12 mm.

[0090] Comparative Example 1

[0091] The fertilizer is prepared according to the method of Example 1, except that all the stirring paddles 9 on the first screw 21 and the second screw 22 of the press are removed; after the press is started and the premix is fed in, the hole plate 6 of the press is deformed by extrusion and cannot extrude and granulate the fertilizer.

[0092] Comparative Example 2

[0093] The fertilizer is prepared according to the method of Example 1, except that all the stirring paddles 9 on the first screw 21 and the second screw 22 of the press are removed, and 2% by weight of starch is added to the premix; after the press is started and the premix is fed in, the hole plate 6 of the press can extrude continuous long strip fertilizer, but does not have micro-holes and cannot be naturally broken, and needs to be cut into granules additionally.

[0094] Test Example 1

[0095] The fertilizers prepared in Examples 1-4 and Comparative Example 2 are tested for dissolution speed, turbidity, viscosity, oil absorption rate, pore size and porosity, and the results are shown in Table 1.

[0096] Dissolution speed: the dissolution time of 10 g of fertilizer in 100 mL of water.

[0097] Turbidity: measured by turbidimeter.

[0098] Viscosity: the viscosity of a solution of 10 g fertilizer dissolved in 100 mL water. Refer to the determination method of liquid viscosity in GB / T 22235-2008 for testing.

[0099] Oil absorption rate: the pore condition of the granule is reflected by the oil absorption rate index, which is detected according to the "4.4 oil absorption rate gravimetric method" in HG / T 3280-2011 porous granular ammonium nitrate.

[0100] Pore size and porosity: refer to the mercury intrusion method in GB / T 21650.1-2008 for determination.

[0101] Table 1.

[0102]

[0103] As can be seen from Table 1, the microporous needle-shaped fertilizer of the present application has faster dissolution speed, lower solution viscosity, lower turbidity and larger oil absorption rate, and can be better applied to large-area drip irrigation systems.

[0104] The preferred embodiments of the present application are described in detail above in combination with the drawings, but the present application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0105] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the present application will not further describe various possible combination manners.

[0106] In addition, various different embodiments of the present application can also be combined in any manner, as long as it does not deviate from the technical concept of the present application, and it should also be considered as disclosed content of the present application.

Claims

1. A press for making microporous needle-shaped fertilizer, characterized by, The pressure machine comprises a barrel (1) and double screws arranged in the barrel (1); a feeding port (5) is arranged on the side of the barrel (1), and a hole plate (6) is arranged on the bottom surface of the barrel (1); the double screws comprise first and second screws (21 and 22) arranged side by side and rotating in opposite directions, the threads of the first screw (21) and the threads of the second screw (22) are engaged with each other, one end of the double screws close to the feeding port (5) is connected with a driving mechanism, and the ends of the first and second screws (21 and 22) close to the hole plate (6) are respectively equipped with 2-6 stirring paddles (9); The diameters of the first and second screws (21 and 22) are respectively 20-50 cm, and the lengths of the first and second screws (21 and 22) are respectively 40-100 cm; The length of the stirring paddle (9) is 5-22 cm, the width of the stirring paddle (9) is 1-5 cm, and the thickness of the stirring paddle (9) is 0.5-3 cm; the inner ends of the plurality of stirring paddles (9) surround a gap area (10), the diameter of the gap area (10) is 2-10 cm, and the distance between the inner ends of two adjacent stirring paddles (9) is 2-10 cm; The stirring paddle (9) comprises first and second stirring paddles (91 and 92) assembled on the first and second screws (21 and 22), the first and second stirring paddles (91 and 92) can rotate on the same plane, and the outer end of the first stirring paddle (91) extends into the space between two adjacent second stirring paddles (92); The thickness of the hole plate (6) is 0.5-2 cm, the hole plate (6) is provided with a plurality of holes (61), the diameter of the hole (61) is 1-3 mm, and the distance between the holes is 2-10 mm; The distance between the stirring paddle (9) and the hole plate (6) is 1-5 mm; A non-hole belt (62) is arranged in the middle of the hole plate (6), the non-hole belt (62) comprises first, second and third areas (63, 64 and 65) connected in sequence, the first and third areas (63 and 65) are rectangular, the length of each of the first and third areas (63 and 65) is 4-14 cm, and the width of each of the first and third areas (63 and 65) is 1-4 cm; the second area (64) is circular, and the diameter of the second area (64) is 2-5 cm; The driving mechanism comprises a driving motor (4) connected to the first screw (21) and a gear set (12) connected between the first and second screws (21 and 22); the gear set (12) comprises first and second gears (121 and 122), the first gear (121) is fixed on the first screw (21), the second gear (122) is fixed on the second screw (22), and the first and second gears (121 and 122) are engaged with each other; The driving motor (4) is drivingly connected with the first screw (21) through a speed reducer (41); the first and second screws (21 and 22) can rotate in opposite directions at the same speed. The inner wall of the barrel (1) is further provided with an internal thread (11), the depth of the internal thread (11) is 1-8mm, the width is 1-5mm, and the thread rise angle is 1-15°; The distance between the screw flight of the first screw rod (21) and the second screw rod (22) and the inner surface of the barrel (1) is 0.1-5mm respectively.

2. The press according to claim 1, wherein, The center distance of the first screw rod (21) and the second screw rod (22) is 20-50cm.

3. The press machine of claim 1, wherein, The screw channel depth of the first screw rod (21) and the second screw rod (22) is 5-10cm respectively, the screw flight width is 1-5cm respectively, and the thread rise angle is 2-10° respectively.

4. The press of claim 1 wherein, The thickness of the barrel (1) is 1-5cm.

5. The press of claim 1 wherein, The tail of the barrel (1) corresponding to the stirring paddle (9) is provided with a cooling jacket (7), and the cooling jacket (7) is connected with a cooling water pipe (8).

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