JP2002362991A - Apparatus for manufacturing coated fertilizer and method of manufacturing this apparatus and coated fertilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the damage of films by the collision of fertilizer particles 8 under treatment against the inside surface of a guide pipe 6 and the occurrence of adhesion, deposition and consolidation of a coating material and the fertilizer particles 8 to the inside surface of the guide pipe 6 and to prevent the generation of static electricity between the inside surface layer of the guide pipe 6 for preventing the same and the polymer in the coating material and the peeling and damage of the inside surface layer with an apparatus for manufacturing the coated fertilizer equipped with a jet column 1 into which the fertilizer particles 8 are supplied, a throttling section 3 which spouts air currents upward from a bottom 2 of the jet column 1, the guide pipe 6 which is erected upward of the throttling section 3 and a spray nozzle 9 which sprays the coating material into the guide pipe 6. SOLUTION: A plating layer of rigid chromium carbide (Cr+Cr23 C6 ) is formed on the inside surface of the guide pipe 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a coated fertilizer having a film formed on the surface of fertilizer particles in order to control the elution of fertilizer from the fertilizer particles, and an apparatus and a method for producing the coated fertilizer. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Conventionally, a coated fertilizer manufacturing apparatus includes a jet tower to which fertilizer particles are supplied, a throttle section for jetting an airflow upward from the bottom of the jet tower, and a guide pipe standing above the throttle section. And a spray nozzle for spraying a coating material in a guide tube are known (Japanese Patent Publication No. 2-310).
No. 39). Further, there is also known an apparatus in which a fluorine resin lining is provided as an inner surface layer of a guide tube in the above-mentioned coated fertilizer production apparatus (Japanese Patent Application Laid-Open No. H10-156166).

[0003] These coated fertilizer production devices are jet-type devices in which a coating material is adhered and dried while fluidizing fertilizer particles as a jet, and the production of coated fertilizer using these devices is performed by removing fertilizer particles supplied into a jet tower. While blowing up into the guide tube with the airflow spouting from the constricted part, the fertilizer particles that have fallen around from the upper end of the guide tube are again blown up with the airflow, and while repeating this, the coating material containing the usual polymer is sprayed onto the fertilizer particles from the spray nozzle After the spraying and drying of a predetermined amount are completed, the supply of the airflow from the narrowing section is stopped, and the coated fertilizer particles on which the coating material has been formed are dropped from the narrowing section and taken out.

[0004]

In the above-mentioned conventional jet-type coated fertilizer manufacturing apparatus, in which the guide pipe is not provided with a special inner surface layer, the fertilizer particles being processed collide with the inner surface of the guide pipe. In addition to the coating being easily damaged, the coating material and the fertilizer particles adhere to the inner surface of the guide tube, accumulate and narrow the inside of the guide tube, or form (consolidate) a massive coated fertilizer particle adhered to each other. There are easy problems. If the coating of the coated fertilizer particles is damaged, the initial dissolution control by the coating is no longer possible. When the coating material and fertilizer particles adhere and accumulate on the inner surface of the guide pipe and narrow the inside of the guide pipe, it becomes difficult to form a jet containing fertilizer particles, and in order to maintain a stable jet, the operation is periodically interrupted. This needs to be removed, which causes a reduction in manufacturing efficiency. Consolidation also reduces the quality of the resulting coated fertilizer.

On the other hand, among the conventional jet-type coated fertilizer production apparatuses, the one in which the inner surface layer of the guide pipe is lined with a fluororesin, the impact when the fertilizer particles being processed collide with the inner surface of the guide pipe is used. A fluororesin lining is applied from the viewpoint of softening, and has an advantage that not only damage to the coating is easily suppressed but also adhesion and accumulation of the coating material and fertilizer particles on the inner surface of the guide tube and solidification can be suppressed.

However, in the case of a coated fertilizer manufacturing apparatus in which a fluororesin is lined on the inner surface of the guide tube, static electricity is generated between the fluororesin and the polymer contained in the coating material, and flammable as a solvent for the coating material. When a solvent is used, there is a concern about ignition of vaporized components, dust explosion due to combustible dust generated, and the like. Further, there is also a problem that the abrasion resistance of the lining layer of the fluororesin is weak, and the base material is exposed due to peeling or abrasion in a short period of time, so that maintenance management is troublesome.

[0007] The present invention has been made in view of the above-mentioned conventional problems, and is directed to the production of a coated fertilizer by a jet method.
In addition to preventing the damage of the coating due to the fertilizer particles colliding with the inner surface of the guide tube during the treatment, the deposition of the coating material and the fertilizer particles on the inner surface of the guide tube, and the occurrence of solidification, the guide tube for preventing these is prevented It is an object of the present invention to prevent generation of static electricity between the inner surface layer and the polymer in the coating material, and also prevent the inner surface layer from being peeled or worn.

[0008]

Means for Solving the Problems In a jet-type coated fertilizer manufacturing apparatus, the present inventors have found that a coating material and a fertilizer particle being processed adhere to the inner surface of a guide tube in a jet tower, and are deposited or solidified. Is caused by the affinity between the inner surface of the guide tube, the coating material (particularly, the polymer contained in the coating material), and the fertilizer particles to which the coating material adheres. Considering that it is due to friction with the inner surface of the guide tube, we studied the inner layer of the guide tube, which has a small affinity for the coating material and the fertilizer particles to which it is attached, and has a small frictional resistance. In particular, if the damage of the coating is not the impact at the time of collision with the inner surface of the guide tube but friction is the main cause,
As the inner surface layer, a hard material having excellent wear resistance can be used as long as the frictional resistance is small.As a result of examination including this hard material, it was found that a plated layer of hard chromium carbide was most suitable. It has been reached.

That is, the present invention provides a jet tower to which fertilizer particles are supplied, a throttle section for jetting out an airflow upward from the bottom of the jet tower, a guide pipe standing above the throttle section, and a guide pipe. A coated fertilizer manufacturing apparatus provided with a spray nozzle for spraying a coating material, wherein a plated layer of hard chromium carbide is formed on at least an inner surface of a guide tube.

According to the present invention, the hard chromium carbide plating layer is excellent in abrasion resistance and is not only a conductive material that can prevent generation of static electricity, but also has an affinity for the coating material and the fertilizer particles to which the coating material adheres. Therefore, the object of the present invention can be achieved because the frictional resistance is small and the frictional resistance can be reduced.

According to the present invention, the hard chromium carbide plating layer is also formed on the inner surface at the bottom of the jet tower and on the jet tower side surface of the throttle portion. Is included as a preferred embodiment thereof. According to the former, it is possible to more reliably prevent damage to the film and the occurrence of caking, and according to the latter, it is possible to more reliably prevent adhesion.

The present invention also relates to a method of manufacturing a coated fertilizer manufacturing apparatus according to the present invention, wherein the hard chromium carbide plating layer has irregularities on the surface. Blasting the surface,
An object of the present invention is to provide a method of manufacturing a coated fertilizer manufacturing apparatus, characterized in that a blasted surface is polished while leaving irregularities by blasting, and then a hard chromium plating layer is formed on the polished surface. According to the manufacturing method of the coated fertilizer manufacturing apparatus according to the present invention, the surface of the hard chromium carbide plating layer can be easily and surely brought into the uneven state in which the effect of preventing adhesion is easily improved.

Further, the present invention provides a method for producing a coated fertilizer, characterized by producing a coated fertilizer using the coated fertilizer producing apparatus according to the present invention. According to the method for producing a coated fertilizer according to the present invention, damage to the coating due to the fertilizer particles being processed colliding with the inner surface of the guide tube, and adhesion and deposition of the coating material and fertilizer particles on the inner surface of the guide tube are generated. It is possible to produce coated fertilizer while preventing static electricity between the inner surface layer of the guide tube and the polymer in the coating material, and also preventing peeling and wear of the inner surface layer, in order to prevent these problems. You can do it.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, based on FIG. 1 and FIG.
An example of the coated fertilizer production apparatus according to the present invention will be described. FIG.
2 is an overall configuration diagram, and FIG. 2 is an enlarged view of the jet tower 1 in FIG.

The jet tower 1 has a circular cross section having a mortar-shaped bottom 2. The inclination angle of the bottom 2 is determined at the time of taking-out described later, by the fertilizer particles 8 having been completely covered.
(See FIG. 2) may be any angle as long as it is ejected without large resistance.

The central part (lowest part) of the bottom part 2 of the jet tower 1
Is connected to an extraction pipe 5 provided with a valve 4 at a lower end portion. In the jet tower 1, a cylindrical guide pipe 6 is provided upright above the throttle section 3 with a space between the bottom section 2 and the guide section 6. In other words, the guide tube 6 is supported or suspended in a state where the center axis thereof is oriented in the vertical direction and the guide tube 6 is set up at an interval from the bottom 2. The throttle unit 3 causes the airflow supplied by the blower 13 described later to be jetted upward from the bottom 2 into the jet tower 1, and the airflow causes the fertilizer particles 8 to fall out of the jet tower 1 and fall into the pipe 5 without rolling. Alternatively, an orifice or a nozzle is formed at a location where the flow path of the connection portion of the extraction pipe 5 to the jet tower 1 is narrowed down to make it in a jet flow state. Further, the guide tube 6 may be a cylindrical member having no hole in the peripheral surface. However, in order to adjust the flow velocity of the jet in the guide tube 6, a cylindrical member having a hole in the peripheral surface, a punching board or a wire mesh is formed in a cylindrical shape. It can also be a member rounded in a shape.

Fertilizer particles 8 can be supplied from the fertilizer particle hopper 7 to the jet tower 1. Further, as clearly shown in FIG. 2, a spray nozzle 9 is provided in the vicinity of the center of the throttle unit 3 in an upward direction.
The coating material supplied from the coating material adjusting tank 11 can be sprayed toward the inside of the guide tube 6 by the pump 10 shown in FIG. The tip position of the spray nozzle 9 is
As long as the coating material can be sprayed toward the inside of the guide tube 6, it may be above or below the narrowest portion of the narrowed portion. The coating material adjusting tank 11 is provided with a stirring blade 12 so that each material constituting the coating material can be stirred and mixed here.

As shown in FIG. 1, air or gas (for example, an inert gas such as nitrogen) sent to a heater 14 by a blower 13 is supplied to a middle portion of the extraction pipe 5 as a heated air flow. The gas is jetted upward from the bottom of the jet tower 1 through the throttle unit 3.
The air flow jetted into the jet tower 1 mainly blows up in the guide pipe 6 and is discharged at an outlet 15 provided at the top of the jet tower 1 (FIG. 2).
) To the bag filter 16 to remove accompanying solids. After the liquid component vaporized from the coating material is condensed and removed by the cooling condenser 17, the liquid component is again sent to the heater 14 by the blower 13. It is supposed to be.

In particular, in the coated fertilizer manufacturing apparatus according to the present invention, a plating layer of hard chromium carbide is provided on at least the inner surface of the guide tube 6. In the present invention, hard chromium carbide means chromium carbide alloy (Cr and Cr
₂₃ C ₆ alloy) and contains a carbide having a composition of Cr ₂₃ C _{6 in} addition to Cr. Therefore, when a plated layer is formed, the surface is harder than hard chromium and is more resistant to abrasion and peeling (for example, ,
Suzuki Zhangsuke, "Hard chromium carbide plating under no lubrication", Practical Surface Technology, Vol. 35, No. 7, (1988), p. 360). Therefore, even if it is provided as an inner layer of the guide tube 6, peeling and wear can be prevented. Hard chromium carbide is a conductor and can prevent the generation of static electricity, and at the same time, has a small frictional resistance, so that the fertilizer particles 8 being processed collide with the inner surface of the guide tube 6 to damage the coating. Can also be suppressed. Further, the hard chromium carbide plating layer has a small affinity for the coating material and the fertilizer particles 8 to which the coating material adheres, and has a property that these hardly adhere. Therefore, the hard chromium carbide plating layer is applied to the inner surface of the guide tube 6. By providing the coating material, it is possible to prevent the coating material and the fertilizer particles 8 from adhering and depositing on the inner surface of the guide tube 6 and consolidation due to this.

The plating layer of hard chromium carbide is preferably provided on the entire inner surface of the guide tube 6, but in particular, a portion of the guide tube 6 where the coating material and the fertilizer particles 8 are likely to adhere (for example, a lower portion of the guide tube 6). It can also be only.
In order to more reliably suppress the occurrence of caking, in addition to the inner surface of the guide tube 6 (preferably the entire inner surface of the guide tube 6), the inner surface of the bottom 2 of the jet tower 1 and the jet tower 1 side of the throttle unit 3 It is preferable to provide a hard chromium carbide plating layer also on the surface.
This is because the fertilizer particles 8 to which the coating material adheres stay and contact the bottom 2 of the jet tower 1 or the surface of the throttle unit 3 on the side of the jet tower 1 to cause consolidation. The coating may be damaged when 8 falls on the bottom portion 2 or the squeezed portion 3. If a plated layer of hard chromium carbide is provided also at these locations, consolidation and damage of the coating are prevented there. It is thought that it is possible.

It is desirable that the hard chromium carbide plating layer has an effective thickness after plating of about 60 μm in order to maintain abrasion resistance. However, in order to reduce friction, the effective thickness after plating is effective. Is preferably 10 μm to 50 μm.

The hard chromium carbide plating layer has irregularities on the surface. More specifically, when the surface is observed with a microscope, the plating layer is formed of bubbles or rounded particles as schematically shown in FIG. It is preferable to have aggregated fine irregularities. With such irregularities, it is possible to reduce the contact area particularly when the fertilizer particles 8 to which the coating material adheres come into contact, and it is possible to make the fertilizer particles 8 less likely to adhere. The irregularities preferably have a height difference of about 40 to 60 μm.

The plating layer of hard chromium carbide having fine irregularities in the form of bubbles or round particles on the surface can be easily obtained in the following manner.

First, the base surface of the portion to be plated with hard chromium carbide is polished (for example, buffed) as necessary, and then blasted. Blasting is a process in which the ground material is ground and hardened by impact by striking the ground material with a method such as centrifugal projection or water injection, etc. Sand blasting using, for example, silica sand, river sand, or crushing is preferable, and sand blasting using a polishing material of # 400 or less, particularly, sand blasting of # 60 to # 100. Sandblasting using a scavenging material is preferred. Then, by this blasting, a matte-like uneven surface having a height difference of 50 to 75 μm is formed on the base surface, and the formed uneven surface is polished while leaving the unevenness by the blasting. By plating the polished surface with the hard chromium carbide,
A hard chromium carbide plating layer having fine irregularities in the form of collected cells can be provided. Polishing of the uneven surface by the blast processing can be performed by, for example, buffing, and the height difference between the unevenness is 10 to 30%, particularly 15 to 25%.
It is preferable that the degree of polishing is polished and the upper surface of the convex portion is mirror-finished.

FIGS. 4A and 4B show the above procedure, wherein FIG. 4A schematically shows a cross section of the base after blasting, and FIG.
FIG. 3A is a diagram schematically showing a cross section of a ground where an uneven surface is polished, and FIG. 3C is a diagram schematically showing a cross section of a ground where hard chromium carbide is plated on the uneven surface of FIG. In the figure, A is a base, and B is a plating layer.

Further, the present invention will be described together with the operation states of the apparatus shown in FIGS.

First, while the valve 4 is closed, the blower 13 is operated, and air or gas heated by the heater 14 is extracted and supplied to the jet tower 1 through the pipe 5 and the throttle 3. This air or gas is preferably supplied as a circulating gas as described above to minimize emissions.

When the fertilizer particles 8 are supplied from the fertilizer particle hopper 7 into the jet tower 1, the fertilizer particles 8 are blown up in the guide tube 6 by the heated airflow spouted from the throttle unit 3 to form a jet. At the same time, the fertilizer particles 8 that have fallen from the upper end of the guide tube 6 to the surroundings slide down the bottom 2 of the jet tower 1 and the surface of the throttle unit 3 on the jet tower 1 side, and are again blown up into the guide pipe 6 as a jet. repeat.

The type of fertilizer particles 8 that can be treated in the present invention is not particularly limited, and conventionally known ones can be treated. Specifically, for example, urea, aldehyde condensed ureas such as formaldehyde condensed urea, guanyl urea sulfate, lime nitrogen, ammonium nitrate, ammonium sulfate, ammonium chloride, ammonium dihydrogen phosphate, ammonium compounds such as diammonium hydrogen phosphate, Potassium salts such as potassium nitrate, potassium chloride and potassium sulfate; calcium salts such as calcium phosphate, calcium sulfate, calcium nitrate and calcium chloride; magnesium salts such as magnesium nitrate, magnesium chloride, magnesium sulfate and magnesium phosphate; ferrous nitrate; nitric acid Iron salts such as ferric, ferrous phosphate, ferric phosphate, ferrous sulfate, ferric sulfate, ferrous hydrochloride, and ferric hydrochloride, and double salts thereof, or these And a composite of two or more. It is preferable that these fertilizer particles 8 have a shape close to a spherical shape. Usually, from the viewpoint of the elution characteristics of the fertilizer when it is a coated fertilizer, those having a narrow particle size distribution are preferable. The particle diameter of the fertilizer particles 8 to be treated in the present invention is 0.5 to
It is preferably 10 mm, more preferably 1 to 5
mm.

Normally, after the fertilizer particles 8 are preheated to the coating temperature, the pump 10 supplies the coating material from the coating material adjusting tank 11 to the spray nozzle 9, and the fertilizer flowing as a jet in the guide pipe 6. The coating material is sprayed on the particles 8 and adhered thereto.

The temperature of the coating is not particularly limited, but usually, the surface temperature of the fertilizer particles 8 is preferably 40 ° C. to 120 ° C. In addition, the air flow for forming the jet is preferably set to a temperature and a flow rate at which the solvent contained in the coating material is quickly vaporized after adhering to the fertilizer particles 8. , Heater 1 as shown in FIG.
Preferably, the air stream is heated in step 4.

The coating material is obtained by dissolving a film-forming material such as a polymer or other additives in a solvent (some of them may be in a dispersed state). A curable resin or a thermoplastic resin can be used. Examples of the thermoplastic resin include α-olefin (co) polymers such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-butene copolymer, and ethylene-octene copolymer. The same applies to the following.), Α- such as ethylene-vinyl acetate copolymer.
Olefin-vinyl ester copolymers, polyvinyl chloride, vinyl halide polymers such as polyvinylidene chloride, poly (meth) acrylates including poly (methyl) acrylate, and copolymers thereof;
Α-olefin- (meth) acrylate copolymers such as ethylene-ethyl (meth) acrylate, polymers of aromatic vinyl compounds such as styrene, polylactic acid, polycaprolactone, polyesters of aliphatic dicarboxylic acids and diols, and Examples thereof include natural or petroleum waxes such as petroleum wax, paraffin wax, and microcrystalline wax, rosin-based resins, and terpene-based resins. Of these, α-olefin (co) polymers and α-olefin-vinyl ester copolymers are preferred from the viewpoint of controlling the elution of the fertilizer of the coated fertilizer and from the viewpoint of coating strength. Of the α-olefin (co) polymers, polyethylene is preferred, and low molecular weight polyethylene is more preferred because it has biodegradability. When a low-molecular-weight polyethylene is used, a mechanical strength is liable to occur by itself, so that an α-olefin (co) polymer such as another ethylene-octene copolymer or an α-olefin such as an ethylene-vinyl acetate copolymer is used. It is preferable that an olefin-vinyl ester copolymer and the like coexist. Examples of the thermosetting resin include conventionally known urethane resins, alkyd resins, melamine resins, epoxy resins, and phenol resins. Among these, a thermoplastic resin is preferable as the film forming material of the coated fertilizer. The amount of polymer is
It is preferably from 10 to 97% by weight, more preferably from 80 to 40% by weight, based on the whole film forming material.

The coating material may contain, as a film-forming material, an inorganic filler or an organic filler in addition to the polymer.
Examples of the inorganic filler include metal oxides such as talc, clay, calcium carbonate, diatomaceous earth and titanium oxide, and powdery inorganic compounds such as sulfur powder. The amount of the inorganic filler is 3 in the total coating material forming material.
It is preferably from 80% by weight to 80% by weight, more preferably from 20 to 60% by weight. Above this range, the physical strength of the coated fertilizer tends to decrease. Examples of the organic filler include starch, oxidized starch and modified starch, cellulose and carboxy-modified cellulose, agar, xanthone, and the like. The amount of these organic fillers is preferably 40% or less based on the total weight of the film forming material. Above this, it becomes difficult to control the elution of fertilizer from the coated fertilizer. The organic filler is sometimes used as a dissolution rate regulator for the fertilizer of the initial dissolution-suppressed coated fertilizer.

[0034] Either the organic filler or the inorganic filler may coexist, but from the viewpoint of the temperature dependence of the elution of fertilizer from the coated fertilizer, the inorganic filler may be contained. Is preferred.

The coating material used in the present invention, besides these,
It may contain a fertilizer elution modifier, a coloring agent, an anti-caking agent, and other additives.

As a dissolution regulator of fertilizer from the coated fertilizer, a conventionally known cationic, nonionic or anionic surfactant can be used. Examples of the nonionic surfactant include alkyl esters or alkyl ethers of polyethylene oxide, and alkyl esters or alkyl ethers of polypropylene oxide. Among these, nonionic and anionic surfactants can be suitably used. These surfactants can be used alone or in combination of two or more. The amount of such a surfactant is preferably from 0.01 to 20% by weight, more preferably from 0.1 to 10% by weight, based on the coated fertilizer.

Prior to spraying from the spray nozzle 9, the coating material is sufficiently dissolved or dispersed in the coating material adjusting tank 11 so that each component can be uniformly attached to the fertilizer particles 8. It is preferable to carry out, and if necessary, heat dissolution can be performed. The solvent used for the coating material is not particularly limited, but preferably dissolves at least the polymer which is the main film forming material. Specifically, aliphatic hydrocarbons such as hexane and heptane; aromatic hydrocarbons such as benzene, toluene and xylene; ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate and butyl acetate; tetrachloroethylene and dichloroethane And halogenated hydrocarbons such as trichloroethane.

A predetermined amount of a coating material is sprayed and adhered to the fertilizer particles 8 flowing as a jet in the guide pipe 6, and the adhered coating material is dried by an air stream to form a desired coating on the surface of the fertilizer particles 8. Is formed, the supply of the airflow by the blower 13 is stopped and the valve 4 is opened, whereby the coated fertilizer can be taken out. The amount of the coating adhered to the fertilizer particles 8 is usually 3 to 30% by weight, preferably 4 to 20% by weight.
It is. The coated fertilizer obtained by using the apparatus of the present invention is obtained without damage or consolidation of the coating and without charging due to the presence of the hard chromium carbide plating layer.

[0039]

The present invention will be specifically described below with reference to examples and comparative examples.

Example 1 An apparatus as shown in FIGS. 1 and 2 was used as a guide tube in a jet tower, and after buffing the inner surface, plating with hard chromium carbide was performed to a thickness of 30 μm to 50 μm. The coated fertilizer was produced at a production rate of 10,000 kg / day for 10 days.

The jet tower, the guide tube and the throttle are all made of SUS304, and the jet tower has a height of 50,000 mm.
A guide tube with a height of 1,
Those having a diameter of 600 mm and an inner diameter of 338 mm were used.

The results are shown in Table 1.

The measurement and evaluation of each measurement item in Table 1 were performed as follows.

Anti-adhesion property: The inner surface of the guide tube at the end of daily production was visually observed, and ◎ indicates that no adhesion of the coating material and fertilizer particles was observed, ○ indicates that slight adhesion was observed, and Those with adhesion were rated as x.

Anti-consolidation property: The produced coated fertilizer was sieved to find the consolidation, and if no consolidation was found, ◎ indicates that no consolidation was found; 、, x was found when a large amount of solidified was found.

Film Damage Prevention: A 10 g sample was prepared from the manufactured coated fertilizer, immersed in 10 ml of blue-black ink for writing preheated to 35 ° C. for 2 hours, filtered, collected and washed with water. Dry with warm air at ℃
Observation by a stereoscopic microscope showed that 傷 indicates that no scratches penetrated by the ink were observed, を indicates that slight scratches were observed, and × indicates that many scratches were observed.
And

Abrasion resistance: After completion of the production for 10 days, the inner surface of the guide tube was visually observed, and ◎ indicates that no abnormality was observed, and X indicates that abnormality was observed.

Antistatic property: When inspecting the inside of the guide tube at the end of daily production, those who did not feel static electricity on the human body were evaluated as ◎, and those who felt it were evaluated as x.

Example 2 After buffing the inner surface of the guide tube, sand blasting was performed using sand # 100, and the uneven surface was polished while leaving the formed unevenness. (Trade name "Blastron", Chiyoda Daiichi Kogyo Co., Ltd.) is applied in a thickness of 30 μm to 50 μm,
A coated fertilizer was produced in the same manner as in Example 1 except that a hard chromium carbide plating layer having irregularities on the surface was used.
The measurement and evaluation of each evaluation item were performed in the same manner as described above.

Table 1 shows the results.

EXAMPLE 3 Hard chromium carbide was plated on the inner surface of the guide tube, the inner surface of the bottom of the jet tower, and the jet tower side surface of the throttle by the same processing and processing as in Example 1. A coated fertilizer was produced in the same manner as in Example 1 except that a layer was provided.
The measurement and evaluation of each evaluation item were performed in the same manner as described above.

Table 1 shows the results.

Comparative Example 1 Example 1 was the same as Example 1 except that the inner surface of the guide tube was left as a SUS304 base without a hard chromium carbide plating layer.
A coated fertilizer was manufactured in the same manner as in Example 1, and the measurement and evaluation of each evaluation item were performed in the same manner as in Example 1.

Table 1 shows the results.

Comparative Example 2 The same procedure as in Example 1 was carried out except that the inner surface of the guide tube was lined with a tetrafluoroethylene resin to a thickness of 2 mm instead of forming the hard chromium carbide plating layer. Manufacture of fertilizer was performed, and measurement and evaluation of each evaluation item were performed in the same manner as in Example 1.

Table 1 shows the results.

[0057]

[Table 1]

In Example 1 in which a hard chromium carbide plating layer having a smooth surface was provided on the inner surface of the guide tube, as is clear from the comparison with Comparative Example 2, the case where the lining of ethylene tetrafluoride resin was applied was used. As a result, the anti-adhesion property, the anti-caking property, and the anti-damage property of the coating film are sufficiently high in practical use, as is clear from comparison with Comparative Example 1. The effect is shown. Further, as is apparent from Example 2, when a hard chromium carbide plating layer having irregularities in the form of aggregated cells is used, the anti-adhesion property can be improved, and from Example 3, the amount of the hard chromium carbide plating layer is reduced. It can be seen that the anti-caking property and the damage to the coating film can be improved by providing the inner surface at the bottom of the jet tower and the jet tower side surface of the throttle portion.

[0059]

The present invention is as described above. Damage of the coating due to collision of the fertilizer particles during treatment with the inner surface of the guide tube, adhesion of the coating material and fertilizer particles to the inner surface of the guide tube, and In addition to preventing the occurrence of consolidation, the coating fertilizer can be removed while preventing the generation of static electricity between the inner layer of the guide tube and the polymer in the coating material, and the separation and wear of this inner layer to prevent these. It can be manufactured, and can improve the efficiency, safety, and quality in the production of coated fertilizer, and can reduce the labor of maintenance and management.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an example of a coated fertilizer production apparatus according to the present invention.

FIG. 2 is an enlarged view of a jet tower portion in FIG.

FIG. 3 is a view showing a preferred surface state of a hard chromium carbide plating layer in the present invention.

FIG. 4 is a view showing a procedure for obtaining a hard chromium carbide plating layer having a surface state shown in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spout tower 2 Bottom part 3 Restriction part 4 Valve 5 Extraction pipe 6 Guide pipe 7 Fertilizer particle hopper 8 Fertilizer particle 9 Spray nozzle 10 Pump 11 Coating material adjustment tank 12 Stirrer blade 13 Blower 14 Heater 15 Gas outlet 16 Bag filter 17 Cooling Condenser A Base B Plated layer

Claims (5)

[Claims] 1. A jet tower to which fertilizer particles are supplied, a throttle section for jetting out an airflow upward from a bottom of the jet tower, a guide pipe erected above the throttle section, and a coating material sprayed into the guide pipe. A coated fertilizer manufacturing apparatus, comprising: a spray nozzle having a hard chromium carbide plating layer formed on at least an inner surface of a guide tube. 2. The coated fertilizer production apparatus according to claim 1, wherein a hard chromium carbide plating layer is also formed on the inner surface at the bottom of the jet tower and on the jet tower side surface of the throttle portion. 3. The coated fertilizer production apparatus according to claim 1, wherein the surface of the hard chromium carbide plating layer has irregularities. 4. A blasting process is performed on a base surface of a portion where a hard chromium carbide plating layer is to be formed, and the blasted surface is polished while leaving irregularities due to the blasting process. The method for producing a coated fertilizer production apparatus according to claim 3, wherein: 5. A method for producing a coated fertilizer, comprising producing a coated fertilizer using the coated fertilizer production apparatus according to claim 1.