JP2008163399A - Curing device for agglomerated fine powder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance hardness of agglomerated fine powders by effectively performing steam curing using a cementitious binder so that a post-process can be immediately performed when agglomerating fine powders so as to make the powders easy to handle in a device such as an incinerator, a shaft furnace, and a steelmaking plant, which generates a large amount of the fine powders. <P>SOLUTION: In the device for agglomerating a finely-powdered raw material by adding the cementitious binder and thereafter rapidly increasing compressive strength of the agglomerate by steam curing, there are provided: an injection port at the upper part of a tower-like curing bath for an agglomerated material having insufficient compressive strength; a blowing port at a lower part of the bath for warm air containing water vapor; a removal port at the bottom end of the peripheral part for a hardened agglomerated material; a dispersing board having a conical shape at the top located at the lower part of the curing bath; and a peripheral gap between the periphery of the conical board and an internal wall of the curing bath where cured and strength-increased agglomerated material is filled. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a device that generates a large amount of fine powder, such as an incinerator, a blast furnace, a steel mill, etc. In order to agglomerate the generated fine powder for easy handling, a cement-based binder is used, and steam curing is used to express strength. It is related with the curing apparatus or the curing method which makes it ready for a post process.

  Incinerators, blast furnaces, steelworks, etc. generate a large amount of fine powder separated by a dust remover. The processing of these fine powders is difficult, and it has been considered that the powders are agglomerated by heating and melting. However, melting requires a large amount of heat source, and carbon dioxide gas is generated when the heat source is obtained, and there is a concern about the re-scattering of fine powder, which is not a preferable method in terms of environment and profitability.

Although it can be agglomerated using a cement-based binder, it takes 3 to 7 days to obtain a compressive strength that can be processed and a compressive strength of 7 to 10 N / mm ² or more. When the amount of fine powder discharged per day is in units of tons, a huge amount of site is required to mix with cement-based binder and wait for the expression of compressive strength, which is difficult to achieve. Patent Document 1 discloses a method in which carbon-containing powder is blended with zinc-containing dust and cement is further blended to increase the strength of the agglomerated material and return it to the molten metal. In Patent Document 2, powdered slag that is difficult to use alone due to its fineness is solidified with cement and agglomerated. It is disclosed that the agglomeration is cured as it is or the strength is increased by treatment under steam at high temperature and high pressure. However, neither Patent Document 1 nor Patent Document 2 discloses a specific curing tank.
JP-A-7-166255 JP 2002-86121 A

  In order to agglomerate a large amount of fine powder with a cement-based binder, a vast site is required at room temperature, and normally this site cannot be secured, so steam curing is performed. The method of stacking high in a tower-like tall curing tank and sending water vapor from the lower part is very desirable because it takes no place and has high thermal efficiency. However, since the agglomerate just kneaded with cement is very weak, the lower agglomerate cannot withstand the weight of the upper agglomerate and is crushed or crushed. Even when steam curing is performed, it is necessary to provide a curing room having a large area, and it is difficult to perform treatment using a normal steam curing room. High-temperature and high-pressure curing requires a pressure-resistant and heat-resistant curing tank, and it was difficult to use it for dust treatment.

  When the amount of dust becomes a large amount of one ton or more per day, it is necessary to process promptly without incurring expenses. Agglomeration with a cement-based binder seems preferable because it can be agglomerated without applying energy, but cement-based binders require a date and time to develop the required strength, and generally have a strength of 28 days. I use it. Steam curing is a feasible method for the energy consumed. The present inventors have assumed a tower-shaped curing room that does not take a place and is energy efficient, but the agglomerates located in the lower part cannot withstand the weight of a large amount of agglomerates existing thereon and deform. It was difficult.

  The object of the present invention is to solve the above-mentioned problems, and the constitution thereof is to agglomerate by adding a cement-based binder to a fine powdery raw material, and then steam curing to quickly increase the compressive strength of the agglomerated product. In order to increase, at the upper part of the tower-shaped curing tank, an inlet of agglomerated material still insufficient in compressive strength is provided, an air outlet of warm air containing water vapor is provided at the lower part, and below the outer peripheral part of the lower end part, A hardened agglomerate outlet is provided, and a conical disperser is provided at the bottom of the curing tank, and the agglomerated material is cured and increased in strength between the outer periphery of the disperser and the inner wall of the curing tank. It is characterized by providing an outer peripheral gap that is filled with.

  That is, the present invention provides an efficient steam curing device, which agglomerates a raw material in the form of fine powder called dust to such an extent that it can withstand impact by using a cement-based binder. First, the powder is kneaded with cement and water to agglomerate into dumplings, and precured to such an extent that it can withstand the impact of being charged from the hopper into the curing tank. The pre-cured agglomerate is dropped from the hopper onto the top of the curing tank.

  The curing tank has a tower shape surrounded by a heat insulating wall, and an upper cone-shaped disperser is provided at the center of the lower end, and an outer peripheral gap is provided between the outer periphery of the disperser and the lower end of the curing tank, and a sufficiently hardened lump. Made the chemical fall. The agglomerated material is taken out from the lower end of the outer peripheral gap, and hot air containing water vapor is supplied from the lower part. The warm air containing water vapor is heated from the lower part of the agglomerated material accumulated in the curing tank, heated to the upper part, and then discharged. The agglomerate immediately after being introduced from the hopper is insufficient in strength, but since the distance to the upper part of the agglomerated material is short, it is accumulated in the upper tank while maintaining its shape. In the curing tank, it is heated by warm air containing water vapor, and the strength is quickly increased.

  That is, the agglomerate gradually descends from the top to the bottom and increases its strength as it falls downward. As it goes down, the weight of the agglomerate stacked above it increases, but the strength increases to withstand the pressure. If the agglomerated material that has reached a sufficient strength from the outlet at the lower end of the curing tank is taken out at a rate equal to the supply rate from the hopper at the upper end, the curing tank will always be filled with a certain amount of agglomerated material. Continuous operation is possible.

  According to the present invention, an agglomerate that does not yet have sufficient strength is supplied from the upper end, and the agglomerate that has reached sufficient strength as the curing progresses is taken out from the lower end. It can be used to process large quantities of powder in a small site. Furthermore, steam is supplied from the lower part and rises while curing the agglomerates. The agglomerates located in the lower part come into contact with high-temperature steam, and the steam temperature decreases toward the upper part, but curing is still insufficient. Suitable for curing large agglomerates. As a result, the energy and area required for curing can be extremely saved, and no particular effort is required, and fine powder dust can be processed efficiently.

  The powder in the present invention is a fine powder such as blast furnace dust, steelmaking dust, incineration ash, and automobile final crushed material, and is a fine powder having a diameter of 1 mm or less, preferably 0.5 mm or less, more preferably 0.1 mm or less. is there. It is a fine powder containing dust having a diameter of 1 mm or less that is generated in a large amount of 1 ton or more and 10 tons or more per day. When containing valuables, it can be agglomerated and returned to the furnace for effective use. When no valuables are contained, it can be agglomerated and used for landfill.

As the cement-based binder, Portland cement, ordinary Portland cement, alumina cement and the like can be used.
The agglomerated material in the present invention is obtained by adding water and a cement-based binder to a raw material fine powder and kneading them into a lump shape, preferably a substantially spherical dumpling shape. This is a broad concept including various strengths, such as a sufficiently hard material having a compressive strength of 10 N / mm ² or more. The agglomerated material is generally a ball-like dumpling, and its diameter is 50 mm to 1000 mm, preferably 30 to 500 mm.

  The present invention is implemented using a curing tank as shown in FIG. FIG. 1 is a schematic view of a vertical cross section of the curing tank of the present invention. 1 is a vertical cylindrical curing tank, and the outer wall 2 is a heat insulating wall using a heat insulating material such as glass wool or rock wool. A hopper 3 is provided at the top of the curing tank 1, and an upper cone-like and lower columnar dispersion disc 5 is provided inside the lower end. In the lower part of the curing tank, the width of the outer wall is widened, and the agglomerated material is sufficiently cured by providing an outer peripheral gap 17 between the periphery of the cylindrical portion at the lower end of the disperser 5 and the inner periphery of the lower end of the outer wall 2. It was made to fall in order. The take-out port 4 was formed in a part of the lower end outside the cylindrical portion of the lower part of the dispersion plate 5 provided in the lower part of the curing tank 1.

  In some cases, the dispersing disc 5 is not provided with a lower cylindrical portion, and the curing tank 1 may not have a lower end. If a part of the lower end is provided with a spread, a well-cured agglomerated material can enter from the outer periphery and can be taken out from the outlet 4 just below the spread provided at the lower end. Depending on the type and amount of fine powder to be processed, one or two or more outlets 4 are provided at equal intervals. A known means such as a rotor valve can be used for the take-out port 4.

  Reference numeral 6 denotes a water vapor generator which blows air through a valve 7a. Reference numeral 8 denotes a hot air blower, which is mixed with water vapor through a valve 7b, passes through the disperser 5 through a valve 7c, and is sent from the surface of the conical portion of the disperser 5 to the curing tank 1. The temperature of the warm air containing water vapor is 60 to 90 ° C, the inside is heated to 50 to 60 ° C, and the exhaust temperature is lowered to 30 to 45 ° C.

  Reference numeral 9 denotes a charging conveyor, which drops an agglomerate 10 obtained by granulating a kneaded material kneaded with cement and water through a granulator from the upper part of the hopper 3 in a kneader. The strength at which the agglomerate 10 is not deformed when dropped can be determined because it varies significantly depending on factors such as the type and amount of fine powder, the design of the curing tank, and the operating conditions. If the agglomerated material 10 is piled up to the vicinity of the hopper 3 in the curing tank 1, the impact of dropping is reduced. Further, the hopper may be rolled with a gentle inclination. The curing time is about 10 minutes to 2 hours, more preferably 30 minutes to 1 hour.

  There is no limitation on the kneader, and a commonly used kneader such as an Eirich mixer or a biaxial mixer is used. The granulator is not limited, and a commonly used granulator such as a bread granulator or a briquette machine is used.

  Reference numeral 11 denotes an exhaust pipe, which discharges the warm moist air used for steam curing by the fan 12, and warm air containing water vapor rises from the bottom of the curing tank according to the discharge amount. A table feeder 13 slowly rotates the bottom of the curing tank. Reference numeral 14 denotes a rotating shaft of the table feeder 13. At least one take-out nozzle 15 is provided at a position corresponding to the take-out port 4 of the table feeder 13, and the agglomerates 10 that have reached a sufficient compressive strength are taken out sequentially. Reference numeral 16 denotes an agglomerate receiving tank. Normally, when the curing tank is large, the table feeder 14 is not attached, and a plurality of outlets 4 are provided at equal intervals and discharged directly from the outlets.

A curing tank 1 having an outer diameter of 10 m and a height of 25 m as shown in FIG. 1 was provided. A concrete separator 5 was formed integrally with the foundation in the lower center. Hot air containing water vapor was supplied from a plurality of vent pipes 18 provided in the separator. The temperature of the warm air was about 70 ° C.
As fine powder, cement and water were kneaded into fine blast furnace dust discharged from the blast furnace. To 100 parts by weight of fine powder, 6 to 12 parts by weight of ordinary Portland cement and 2 to 6 parts by weight of water are added and kneaded. In this example, 9 parts by weight of cement and 4 parts by weight of water were added to 100 parts by weight of fine powder and kneaded.

  In FIG. 1, the kneader and the granulator are drawn above, but in reality, they are kneaded and granulated on the ground, and sent onto the hopper 3 using the input conveyor 9. After granulation, it took about 1 hour to reach the upper part of the hopper 3, but during this time, the agglomerated material was not damaged by the impact that dropped the agglomerated material from the hopper 3 onto the agglomerated material accumulated in the curing tank 1. It came to have strength. About 500 kg of agglomerated material was discharged from the take-out nozzle 15 for 1 hour, and the average curing time was 8 hours.

The 130 ° C. steam generated from the steam generator 6 and supplied via the valve 7a was mixed with the warm air supplied via the valve 7b and supplied to the vent pipe 18 via the valve 7c. The water vapor was supplied at 600Nm ³ / time, warm air was supplied at 500Nm ³ / time. The exhaust fan 12 was exhausted at an absolute pressure of 0.1 MPa and 12 m ³ / min.
The obtained agglomerated material had a compressive strength of 7 to 10 N / mm ² .

FIG. 1 is a schematic view of a vertical section of a curing tank according to one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Curing tank 2 Outer wall 3 Hopper 4 Outlet 5 Dispersion board 6 Steam generator 7 Valve 8 Hot air generator 9 Input conveyor 10 Agglomerated material 11 Exhaust pipe 12 Fan 13 Table feeder 14 Rotating shaft 15 Extraction nozzle 16 Agglomerated material receiver Tank 17 Perimeter gap 18 Vent pipe

Claims (5)

In order to increase the compressive strength of the agglomerated material immediately after steam curing after adding cement-based binder to the fine powdery material and agglomerating,
At the top of the tower-shaped curing tank, there is an inlet for agglomerated material that still has insufficient compression strength, an air blowing port for hot air containing water vapor is provided at the bottom, and a hardened agglomeration under the outer periphery of the lower end An apparatus for curing fine powder agglomerates, characterized in that a chemical outlet is provided. A disperser with a conical upper part is provided at the lower part of the curing tank, and an outer peripheral gap is formed between the outer periphery of the dispersing disk and the inner wall of the curing tank to fill the agglomerated material that has been cured and increased in strength. The curing apparatus for agglomerated fine powder according to claim 1. The curing device for agglomerated fine powder according to claim 1 or 2, wherein the cement binder is Portland cement or alumina cement. In order to increase the compressive strength of the agglomerated material immediately after steam curing after adding cement-based binder to the fine powdery material and agglomerating,
By blowing warm air containing water vapor from the bottom of the tower-shaped curing tank, throwing in agglomerates that still have insufficient compression strength from the top, and sequentially taking out the agglomerated hardened material from below the outer periphery of the lower end, Curing method of fine powder agglomerates arranged so as to be located in the lower part of the curing tank in order from the agglomerated material which has progressed curing. A disperser with a conical upper part is provided at the lower part of the curing tank, and an outer peripheral gap is formed between the outer periphery of the dispersing disk and the inner wall of the curing tank to fill the agglomerated material that has been cured and increased in strength. An apparatus for curing a fine powder agglomerated product according to claim 4.