JP2010227769A - Device for manufacturing modified ash and method of manufacturing modified ash - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide modified ash which is used as a cement additive and free from an unburnt carbon and does not cause the eluation of boron when used as a building material. <P>SOLUTION: This device for manufacturing modified ash comprises a slurry tank 2 for turning fly ash FL to slurry, a flotation machine 12 for separating the slurry S2 which is discharged from the slurry tank 2 and through with a surface modifying machine 4, into a lipophilic component and a hydrophilic component, a solid-liquid separator 14 for making a solid-liquid separation of the hydrophilic component to be discharged from the flotation machine 12, a boron elimination device 19 for eliminating the boron from a filtrate L1 to be discharged from the solid-liquid separator 14, and a circulation route 18 for returning the boron-free drain L3 to the slurry tank 2 from the boron elimination device 19. In addition, the inclusion of the boron into the cake C1 of the solid-liquid separator 14 due to the gradual increase of the boron inside the device for manufacturing the modified ash is inhibited. Therefore, when the modified ash is used as a building material, the modified ash free from the eluation of the boron is available. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an apparatus and a method for producing modified ash used as a cement additive or the like from fly ash generated in a coal-fired thermal power plant or the like.

  Conventionally, fly ash generated at coal-fired thermal power plants has been used as a raw material for cement admixtures, concrete admixtures, artificial lightweight aggregates, etc. Therefore, it is necessary to remove unburned carbon. In addition, when low-grade fly ash is used, harmful substances such as boron and chromium exceeding the environmental standard value may diffuse into the surrounding environment. It is necessary to remove in advance.

  Therefore, Patent Document 1 discloses that the flowability of the cement-containing composition when fly ash is used as a raw material for the cement-containing composition by improving the efficiency of sorting and processing the untreated fly ash, A method for producing modified ash has been proposed in which air entrainment and strength development are improved, and the amount of harmful substances (boron and hexavalent chromium) eluted is kept below a certain value.

JP 2007-245007 A

  The method for producing modified ash described in Patent Document 1 measures various physical properties such as BET specific surface area, pH, electrical conductivity and the like for fly ash, and treatment for suppressing elution of boron and the like based on the results. However, it does not disclose a method for removing boron from fly ash. In addition to Patent Document 1, there is no disclosure of a method for removing boron from fly ash.

  Therefore, the present invention has been made in view of the above-described conventional technology, and is a modified ash from which unburned carbon for cement additive is removed, and boron is eluted when used as a construction material. It is an object of the present invention to provide an apparatus and a method for producing modified ash without any problems.

  In order to achieve the above object, as a result of intensive research, the present inventors have eluted boron into the filtrate generated in the dehydration process in the unburned carbon removal process of faraiash using the wet flotation method. The present inventors have found that the present invention has been made.

  That is, the present invention is an apparatus for producing modified ash, a slurry tank for slurrying fly ash, and a flotation machine for separating the slurry discharged from the slurry tank into a lipophilic component and a hydrophilic component; A solid-liquid separator for solid-liquid separation of the hydrophilic component discharged from the flotation machine, a boron removing apparatus for removing boron from the filtrate discharged from the solid-liquid separator, and a boron from the boron removing apparatus A circulation route for returning the waste water from which the water has been removed to the slurry tank is provided.

  And according to this invention, in order to remove boron from the filtrate discharged | emitted from the solid-liquid separator which solid-liquid-separated the hydrophilic component discharged | emitted from a flotation machine, the circulating liquid containing a boron returns to a slurry tank. Therefore, it is possible to prevent boron in the modified ash production apparatus from gradually increasing and mixing boron into the cake of the solid-liquid separator. Thereby, the modified ash from which boron does not elute when used as a construction material can be obtained.

  In the modified ash production apparatus, a front surface reformer that imparts a shearing force while adding a hydrophobic agent to the slurry may be provided in a previous stage of the flotation device. According to this, the shear force is applied to the slurry and the hydrophobic agent to modify the surface of the unburned carbon, or the particles such as unburned carbon and true fly ash contained in the slurry are crushed finely. The removal efficiency of fuel carbon can be increased.

  Further, the present invention is a method for producing modified ash, wherein water is added to fly ash to form a slurry, and the pH of the slurry is adjusted to 5 or more and 10 or less while stirring the slurry. Hydrophobic agent and foaming agent are added to the slurry, stirred to generate bubbles, and by flotation, the unburned carbon in the fly ash is caused to adhere to the bubbles and float, and the unburned carbon in the fly ash is removed. The tail obtained by the flotation is solid-liquid separated, boron is removed from the separated filtrate, and the filtrate after removing the boron is used for the production of the slurry, and the tail is solid-liquid. The modified ash is obtained from the separated cake. According to the present invention, as in the case of the above-described invention, boron is removed from the filtrate to be circulated. Therefore, when used as a construction material, modified ash that does not elute boron can be obtained.

  In the modified ash production method, the slurry has a solid concentration of 1% by mass to 50% by mass, the slurry temperature of 1 ° C. to 50 ° C., and the slurry agitation time of 1 minute to 180 minutes. More preferably, the solid concentration can be 10 mass% to 20 mass%, the temperature can be 20 ° C. to 40 ° C., and the stirring time can be 10 minutes to 60 minutes.

  Furthermore, in the method for producing the modified ash, sulfuric acid or carbon dioxide gas can be used for the pH adjustment.

  As described above, according to the present invention, it is possible to obtain a modified ash from which unburned carbon for cement additive is removed, and in which boron is not eluted when used as a construction material. it can.

It is a flowchart which shows one Embodiment of the manufacturing apparatus of the modified ash concerning this invention. It is a graph for demonstrating the effect of the manufacturing method of the modified ash concerning this invention.

  Next, an embodiment for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an embodiment of a modified ash production apparatus according to the present invention, which is roughly divided into a fly ash tank 1, a slurry tank 2, a surface reformer 4, and a storage tank. 7, the adjustment tank 8, the flotation machine 12, the solid-liquid separator 14, the filter press 15, the boron adsorption tower 19, and the like.

  The fly ash tank 1 is provided for storing fly ash FL carried as waste from a coal-fired thermal power plant or the like and supplying it to the slurry tank 2.

  The slurry tank 2 is provided to add water to the fly ash FL to generate the slurry S1, and includes a stirring blade for stirring the slurry S1. Although not shown in the figure, the slurry tank is provided with a pump or the like for supplying sulfuric acid or carbon dioxide gas to the slurry tank 2. A pump 3 for sending the slurry S1 generated in the slurry tank 2 to the surface reformer 4 is disposed at the subsequent stage of the slurry tank 2.

  The surface reformer 4 modifies the surface of unburned carbon in the slurry S1 by applying a shearing force while adding a hydrophobic agent to the slurry S1 from the slurry tank 2, or particles contained in the slurry S1. It is provided to crush the material. The surface reformer 4 is provided with a hydrophobic agent tank 5 that stores kerosene as a hydrophobic agent and a pump 6 that supplies kerosene to the surface reformer 4. In addition to kerosene, common hydrophobic agents such as light oil and heavy oil can be used as the hydrophobic agent.

  The storage tank 7 is provided to store the slurry S2 from the surface reformer 4 while stirring, and the stored slurry S2 is conveyed to the adjustment tank 8.

  The adjustment tank 8 is provided to add the foaming agent supplied from the foaming agent tank 9 via the pump 10 to the slurry S2 from the storage tank 7 and to mix them. A stirring blade for stirring and mixing the slurry S2 and the foaming agent is provided inside the adjustment tank 8, and the slurry S3 generated in the adjustment tank 8 is flotated at the subsequent stage of the adjustment tank 8. A pump 11 for sending to the machine 12 is arranged.

  The flotation machine 12 is provided to separate the unburned carbon from the slurry S3 by causing the unburned carbon contained in the slurry S3 supplied from the adjustment tank 8 to float on the bubbles. An air supply device (not shown) for supplying air for generating bubbles is provided above the flotation machine 12, and a tail T is sent to the solid-liquid separator 14 at the subsequent stage of the flotation machine 12. The pump 13 is arranged.

  The solid-liquid separator 14 is provided for solid-liquid separation of the tail T including the fly ash discharged from the flotation machine 12, and separates the tail T into the cake C1 and the filtrate L1. The separated cake C1 is fly ash from which unburned carbon is removed, that is, modified ash. The separated filtrate L1 is supplied to the boron adsorption tower 19.

  The filter press 15 is provided for solid-liquid separation of the floss F containing unburned carbon from the flotation machine 12, and the unburned carbon contained in the separated cake C2 can be used as auxiliary fuel or the like. . The filtrate L2 discharged from the filter press 15 is reused in the slurry tank 2 and the like via the pump 16.

  The boron adsorption tower 19 is disposed on a circulation route 18 for returning the filtrate L1 of the solid-liquid separator 14 to the slurry tank 2 in order to remove boron in the filtrate L1 of the solid-liquid separator 14, and has a boron adsorption property. The resin which has is used. This resin includes a glucamine type resin in which an N-methyl-D-glucamino group is introduced into a cross-linked copolymer composed of styrene-divinylbenzene, and 2-amino-2 in a cross-linked copolymer composed of glycidyl methacrylate and divinylbenzene. A resin obtained by reacting -hydroxymethyl-1,3-propanediol, a polymer porous body having a matrix formed of a hydrophilic crosslinking agent, or the like can be used. Waste water L3 from which boron has been removed by the boron adsorption tower 19 is returned to the slurry tank 2 as circulating water.

  Next, operation | movement of the manufacturing apparatus of the modified ash which has the said structure is demonstrated, referring FIG.

  The fly ash FL carried as waste from a coal-fired thermal power plant or the like is stored in the fly ash tank 1 and then supplied to the slurry tank 2 and mixed with water to generate a slurry S1. In addition, sulfuric acid or carbon dioxide gas is added to the slurry tank 2 to adjust the pH of the slurry S1 to 5 or more and 10 or less while stirring the slurry S1, thereby precipitating calcium in the slurry and suppressing scale growth.

  Here, from the viewpoint of the removal efficiency of unburned carbon in the subsequent stage flotation machine 12, the solid concentration of the slurry S1 in the slurry tank 2 is 1% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 20% by mass. % Or less. Further, from the viewpoint of the solubility of gypsum, the temperature of the slurry S1 is 1 ° C. or higher and 50 ° C. or lower, more preferably 20 ° C. or higher and 40 ° C. or lower. Furthermore, the storage time of the slurry S1 is 1 minute or more and 180 minutes or less, more preferably 10 minutes or more and 60 minutes or less from the viewpoint of adhesion and growth of the precipitated gypsum to the seed crystal.

  Next, the slurry S 1 in the slurry tank 2 is supplied to the surface reformer 4 via the pump 3. The surface reformer 4 is supplied with light oil as a hydrophobic agent from a hydrophobic agent tank 5 via a pump 6. In the surface reformer 4, a shearing force is applied to the slurry S <b> 1 to which the hydrophobic agent has been added, or particles contained in the slurry S <b> 1 are crushed extremely finely. The slurry S2 to which the shearing force has been applied is conveyed from the surface reformer 4 to the storage tank 7 and stored in the storage tank 7 while stirring.

  Next, the slurry S2 is transferred from the storage tank 7 to the adjustment tank 8, and the foaming agent is supplied to the adjustment tank 8 from the foaming agent tank 9 via the pump 10. In the adjustment tank 8, the slurry S2 and the foaming are supplied. A slurry S3 is produced by mixing the agent.

  Next, the slurry S3 is supplied to the flotation machine 12 through the pump 11, and air is supplied to the flotation machine 12. Bubbles are generated in the flotation machine 12, and the bubbles are not adsorbed by the hydrophobic agent. While adhering burnt carbon, bubbles that have floated due to adhering unburned carbon are removed. Thereby, the unburned carbon contained in the fly ash FL can be removed.

  Next, the tail T including the fly ash from the flotation machine 12 is solid-liquid separated by the solid-liquid separator 14, and the cake C1 is recovered as the modified ash. In addition, the unburned carbon content of this modified ash is 0.5% by mass or less. Further, the filtrate L1 separated from the solid and the liquid by the solid-liquid separator 14 is introduced into the boron adsorption tower 19 through the pump 17, and boron is removed using a resin having boron adsorptivity. The foaming agent which circulates in the slurry tank 2 and remains in the filtrate L2 is reused.

  On the other hand, the floss F containing unburned carbon discharged from the flotation machine 12 is solid-liquid separated by the filter press 15 to recover unburned carbon. The recovered unburned carbon can be used as an auxiliary fuel in a cement kiln or the like. On the other hand, the filtrate L2 generated in the filter press 15 is returned to the slurry tank 2 via the pump 16. The filtrate L2 can be added to the storage tank 7 or reused in the flotation machine 12 for defoaming when unburned carbon is attached to the bubbles.

  As described above, according to the present embodiment, when the filtrate L1 of the solid-liquid separator 14 is circulated and used, the boron adsorption tower 19 is used to remove boron. Producing modified ash that can prevent boron from gradually increasing and mixing boron into the cake C1 of the solid-liquid separator 14 so that boron does not elute when used as a construction material. Can do.

  Next, an embodiment of the present invention will be described with reference to FIG. FIG. 2 shows the operation of the modified ash production apparatus in which the pH of the slurry S1 in the slurry tank 2 is maintained at 8 to 9 without installing the boron adsorption tower 19 in FIG. It is a graph which shows transition of the boron content rate of the filtrate L1 of the solid-liquid separator 14 performed.

  From this graph, it can be seen that when the operation time of the modified ash production apparatus exceeds 80 hours, the boron content rapidly increases and gradually increases with time. According to the present invention, since the boron adsorption tower 19 is installed on the circulation route 18 and boron is removed from the filtrate (circulated water) L1, an increase in boron content as shown in the graph may be caused. Absent. Therefore, as described above, it is possible to prevent boron from being mixed into the cake C1 of the solid-liquid separator 14, and it is possible to obtain a modified ash that does not elute boron when used as a construction material.

DESCRIPTION OF SYMBOLS 1 Fly ash tank 2 Slurry tank 3 Pump 4 Surface reformer 5 Hydrophobic agent tank 6 Pump 7 Storage tank 8 Adjustment tank 9 Foaming agent tank 10 Pump 11 Pump 12 Flotation machine 13 Pump 14 Solid-liquid separator 15 Filter press 16 Pump 17 Pump 18 Circulation route 19 Boron adsorption tower

Claims (5)

A slurry tank for slurrying fly ash;
A flotation machine for separating the slurry discharged from the slurry tank into a lipophilic component and a hydrophilic component;
A solid-liquid separator for solid-liquid separation of the hydrophilic component discharged from the flotation machine;
A modified ash comprising: a boron removing device for removing boron from the filtrate discharged from the solid-liquid separator; and a circulation route for returning waste water from which boron has been removed from the boron removing device to the slurry tank. Manufacturing equipment.   The apparatus for producing modified ash according to claim 1, further comprising a surface reformer that imparts a shearing force while adding a hydrophobic agent to the slurry in a previous stage of the flotation machine. Add water to fly ash to make a slurry,
While stirring the slurry, the pH of the slurry is adjusted to 5 or more and 10 or less,
Hydrophobic agent and foaming agent are added to the slurry after pH adjustment, and agitation is generated to generate bubbles. By flotation, the unburned carbon in the fly ash is caused to adhere to the bubbles and float to the bubbles. Removing unburned carbon
The tail obtained by the flotation is subjected to solid-liquid separation, boron is removed from the separated filtrate, and the filtrate after removing the boron is used for the production of the slurry, and the tail is subjected to solid-liquid separation. A method for producing modified ash, comprising obtaining modified ash from   The slurry has a solid concentration of 1% by mass or more and 50% by mass or less, the temperature of the slurry is 1 ° C. or more and 50 ° C. or less, and the stirring time of the slurry is 1 minute or more and 180 minutes or less, more preferably, the solid concentration is 10% by mass. The method for producing modified ash according to claim 3, wherein the temperature is 20 ° C. or more and 40 ° C. or less, and the stirring time is 10 minutes or more and 60 minutes or less.   The method for producing modified ash according to claim 3 or 4, wherein sulfuric acid or carbon dioxide gas is used for the pH adjustment.

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