JP2002114547A - Method for producing artificial lightweight aggregate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain optimal production conditions based on the properties of coal ash without conducting test production or inspection. SOLUTION: A desired artificial aggregate is produced by obtaining a coarse powder containing fine particles having particle sizes of <=10 μm by classifying coal ash, forming green pellets 65 by granulating the coarse powder and firing the green pellets 65 to form fired pellets 65". Then, the properties of the fired pellets 65" are calculated by a prediction formula for predicting the properties of the fired pellets, which formula is constituted of the coal ash property parameters exhibiting the properties of the coal ash, and at the same time, the properties of green pellets 65 are calculated by a prediction formula for predicting the properties of the green pellets, which formula is constituted of the same coal ash property parameters. Further, the production conditions of the artificial aggregate using the coal ash are obtained according to the properties of the green pellets 65 when the properties of fired pellets 65" become the desired artificial aggregate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an artificial lightweight aggregate applied to aggregate of lightweight concrete from coal ash.

[0002]

2. Description of the Related Art As one of effective techniques for utilizing coal ash discharged from a coal-fired boiler, there is an artificial lightweight aggregate applied to aggregate of lightweight concrete. The artificial lightweight aggregate using this coal ash is specified in JIS-A5002. For example, the absolute dry specific gravity, which is an index of weight reduction, is 1.0 to 1.0 for M class.
It is set to 1.5.

[0003] Conventionally, in the case of producing artificial lightweight aggregate from coal ash, when coal ash is received from a power plant or the like, the average particle size, specific surface area, true specific gravity, alkalinity, etc. of the coal ash have been known. Analyze the properties of coal ash and determine the manufacturing conditions based on the analysis results so that the artificial lightweight aggregate is within the standard. Then, prepared coal ash and dummy ash that are similar in properties are prepared, and bench tests and pilot tests are performed using these coal ash and dummy ash to produce raw pellets of intermediate products and final products. Produce sintered pellets. After that, the raw pellets and the sintered pellets are respectively inspected, and if the sintered pellets do not have the desired properties as artificial lightweight aggregate, the manufacturing conditions are reviewed based on the properties of the raw pellets and the like, and the sintered pellets are again formed. Prototype and inspection. Then, after repeating the trial and error to find the optimum manufacturing conditions for obtaining a desired sintered pellet, the production of an artificial lightweight aggregate is started under these manufacturing conditions.

[0004]

However, in the above-mentioned conventional method in which trial production and inspection of artificial lightweight aggregates are repeated using coal ash to determine production conditions, a large amount of production conditions are required until optimum production conditions are obtained. In many cases, coal ash is required, so that there is a problem that the production cost is likely to increase due to a decrease in yield. In addition, such prototypes and inspections
This is a burden on the operator, particularly when the production of artificial lightweight aggregate is to be started early after receiving coal ash.

[0005] Accordingly, the present invention provides a method for producing an artificial lightweight aggregate that can determine optimum production conditions based on the properties of coal ash without performing trial production or inspection.

[0006]

In order to solve the above-mentioned problems, a first aspect of the present invention is to classify coal ash to a particle size of 10 μm.
m, forming a coarse pellet containing fine particles having a particle size of m or less, granulating the coarse powder to form a raw pellet, and then firing the raw pellet to form a sintered pellet, thereby producing a desired artificial lightweight aggregate. A method for producing an artificial lightweight aggregate, wherein the properties of the sintered pellets are obtained by a sintered pellet property prediction formula composed of coal ash property parameters indicating the properties of the coal ash, and the same coal ash property parameters are used. Determine the properties of the raw pellets by the configured raw pellet properties prediction formula,
The manufacturing conditions of the artificial lightweight aggregate using the coal ash are obtained based on the properties of the raw pellet when the property of the sintered pellet becomes a desired artificial lightweight aggregate.

According to the above configuration, since the properties of the sintered pellets and the raw pellets are obtained by the sintered pellet property prediction formula and the raw pellet property prediction formula composed of the same coal ash property parameters, respectively, When the property of the pellet is a desired artificial lightweight aggregate, the property of the raw pellet in the intermediate stage before the sintered pellet can be obtained. As a result, the manufacturing conditions can be determined based on the properties of the raw pellets, so that it is possible to eliminate a decrease in yield and a burden on the operator as in the case where the manufacturing conditions are determined by performing trial manufacture and inspection.

According to a second aspect of the present invention, coal ash is classified into coarse powder containing fine particles having a particle size of 10 μm or less, and the coarse powder and a filler are mixed and granulated to form raw pellets. A method for producing an artificial lightweight aggregate for producing a desired artificial lightweight aggregate by firing the raw pellet to form a sintered pellet, wherein coal ash property parameters indicating properties of the coal ash, While obtaining the properties of the sintered pellets by a sintered pellet property prediction formula composed of filler property parameters indicating the properties of the filler, raw pellets composed of the same coal ash property parameters and filler property parameters Determine the properties of the raw pellets by a property prediction formula,
The manufacturing conditions of the artificial lightweight aggregate using the coal ash are obtained based on the properties of the raw pellet when the property of the sintered pellet becomes a desired artificial lightweight aggregate.

According to the above configuration, the properties of the sintered pellets and the raw pellets are obtained by the sintered pellet property prediction equation and the raw pellet property prediction equation composed of the same coal ash property parameter and filler property parameter, respectively. Therefore, when the property of the sintered pellet is a desired artificial lightweight aggregate, the property of the raw pellet in the intermediate stage before the sintered pellet can be obtained. This allows the production conditions to be determined based on the properties of the raw pellets,
It is possible to eliminate a decrease in yield and a burden on an operator as in the case of obtaining a manufacturing condition by performing a trial manufacture or inspection.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The method for manufacturing an artificial lightweight aggregate according to the present embodiment is based on properties of raw pellets and sintered pellets based on properties of coal ash discharged from a coal burning facility such as a power plant using a plurality of types of coal. And an artificial lightweight aggregate manufacturing facility that manufactures sintered pellets under the manufacturing conditions determined based on the properties of the raw pellets and the like obtained by the property prediction device.

The above-mentioned property prediction device includes a data input unit such as a mouse and a keyboard, a screen display unit such as a CRT and an LCD, and a hard disk drive capable of recording various data and a program such as a pellet property prediction routine. Department and
It comprises, for example, a personal computer provided with a memory and an arithmetic unit for executing a program such as a pellet property prediction routine. As shown in FIG. 2, the pellet property prediction routine executed by the property prediction apparatus includes a simple ash prediction formula, a pearlite addition prediction formula, a heavy oil ash addition prediction formula, a sewage sludge incineration ash addition prediction formula, Fluidized bed boiler ash
Equipped with five types of prediction formulas, the incineration ash addition prediction formula, and the properties of sintered pellets and raw pellets can be calculated by substituting data of coal ash property parameters and filler property parameters into these prediction formulas It has become.

That is, the pellet property prediction routine uses “average particle size A (μm)” and “1” as the coal ash property parameters.
% By weight of fine particles less than 0 μm B ”and“ specific surface area C (cm
² ) "," True specific gravity D "and densely packed bulk density E (g / cc)"
And "alkalineness F (%)", and as filler property parameters "perlite weight% G", "heavy oil ash weight% H", "incinerated ash weight% I", and "flow Floor boiler ash wt% J "and incinerated ash wt% K".

The simple ash prediction formula is based on the absolute dry gravity, water absorption (%), and raw powder crushing strength (K
g / P) and coarse powder crushing strength (Kg / P) are determined based on the following sintered pellet property prediction formulas (1-1) to (1-4), respectively, and the moisture content indicating the properties of the raw pellets (%) Is calculated using the raw pellet property prediction formula (1-5).

Absolute dry specific gravity = -0.000809 (A) + 0.004505 (B) + 0.000006186 (C) + 0.2104 (D) + 0.4064 (E)-0.01511 (F) + 0.3573 ... (1-1) Water absorption = 0.00869 ( A) -0.1473 (B) -0.000286 (C) -1.7674 (D) -15.717 (E) +0.3148 (F) +43.833… (1-2) Crushing strength of raw powder = 26.613 (A) +15.195 (B) + 0.00566 (C) +496.45 (D) -14.411 (E) -5.551 (F) -1984.4… (1-3) Crude powder crushing strength = 0.91935 (A) +4.2279 (B) -0.06212 (C) +312.19 (D ) +145.15 (E) +2.457 (F) +576.19… (1-4) Water content = 0.08106 (A) -0.1435 (B) +0.001656 (C) +3.4828 (D) -13.511 (E) -0.07984 (F ) +23.706… (1-5)

The pearlite addition prediction formula is obtained by calculating the absolute pellet specific gravity, the water absorption (%), and the crushing strength (Kg / P) indicating the properties of the sintered pellet as follows:
And (2-3), the water content (%), the crushing strength (Kg / P), the drop resistance (times), and the apparent specific gravity, which indicate the properties of the raw pellets, are estimated from the raw pellet property prediction formula ( 2-
4) Each is calculated based on (2-7).

Absolute dry specific gravity = 0.005868 (A) + 0.007266 (B) + 0.00002138 (C) + 0.4945 (D) -0.08322 (F)-0.01098 (G)-0.07585 ... (2-1) Water absorption = -0.2490 ( A) -0.3328 (B) -0.001227 (C) -8.2926 (D) +0.9606 (F) +0.4419 (G) +52.644… (2-2) Crush strength = 0.06354 (A) +3.1301 (B) -0.0161 ( C) -107.34 (D) +0.4524 (F) +0.001596 (G) +274.93… (2-3) Water content = -0.1795 (A) -0.4655 (B) +0.001531 (C) -4.5370 (D) +0.3182 (F) +0.3061 (G) +41.587… (2-4) Crushing strength = -0.1024 (A) -0.0433 (B) +0.0003789 (C) +1.3991 (D) -0.01968 (F) -0.004135 (G)- 2.272… (2-5) Drop resistance = 0.02491 (A) +0.08726 (B) -0.000123 (C) +0.4066 (D) +0.03785 (F) +0.03487 (G) -1.6222… (2-6) Apparent specific gravity = 0.008968 (A) +0.0209 (B) -0.000055 (C) +0.2513 (D) -0.004971 (F) -0.01100 (G) +0.3460… (2-7)

The formula for predicting the addition of heavy oil ash is based on absolute dry gravity, water absorption (%), and crushing strength (Kg), which indicate the properties of sintered pellets.
/ P) and the following sintered pellet property prediction equations (3-1) to (3-
3), and the moisture content (%) indicating the properties of the raw pellets is determined based on the raw pellet property prediction formula (3-4).

Absolute dry specific gravity = -0.00218 (A)-0.01111 (B)-0.00027 (C) + 3.3595 (D) -1.8218 (E)-0.01 (H)-3.3107… (3-1) Water absorption = 0.3078 ( A) +0.6025 (B) +0.01132 (C) -103.43 (D) +82.183 (E) +0.64 (H) +118.24… (3-2) Crush strength = -0.8432 (A) -2.744 (B) -0.03416 (C) +292.78 (D) -178.87 (E) -1.13 (H) -212.0… (3-3) Water content = -0.0169 (A) -0.2049 (B) +0.00358 (C) +1.6177 (D)- 1.0546 (E) -0.0583 (H) +14.89… (3-4)

The sewage sludge incineration ash addition prediction formula is obtained by calculating the absolute dry gravity, water absorption (%), and crushing strength (Kg / P), which indicate the properties of sintered pellets, as follows: -
1) To calculate the moisture content (%), which indicates the properties of the raw pellets, based on the results of (1) to (4-3)
(4-4).

Absolute dry specific gravity = 0.00862 (A) -0.00726 (B) -0.000373 (C) -0.2296 (D) +0.4500 (E) -0.4893 (F) -0.0024 (I) +1.2697… (4-1) Water absorption Rate = -0.09431 (A) + 0.1124 (B) + 0.00172 (C) + 5.271 (D) -7.6497 (E) + 6.6939 (F) + 0.11 (I) + 2.246… (4-1) Crush strength = -1.6924 (A) -3.3027 (B) +0.04351 (C) -0.9251 (D) -17.239 (E) +13.048 (F) -1.077 (I) +117.42… (4-4) Water content = -0.147 (A)- 0.2766 (B) +0.00579 (C) +6.636 (D) -9.4528 (E) +3.8231 (F) +0.094 (I) +6.819… (4-5)

In addition, the equation for predicting the addition of fluidized bed boiler ash and incinerated ash is obtained by calculating the absolute dry gravity, water absorption (%), and crushing strength ((K) g / P) indicating the properties of sintered pellets as follows. The water content (%), the crushing strength ((K) g / P), and the drop resistance (times) indicating the properties of the raw pellets are obtained based on the pellet property prediction formulas (5-1) to (5-3). And apparent specific gravity are determined based on the raw pellet property prediction formulas (5-4) to (5-7).

Absolute dry specific gravity = 0.002268 (A)-0.03418 (B) + 0.0003878 (C) + 0.2084 (D) + 0.4720 (E)-0.001714 (J)-0.00414 (K) + 0.0936… (5-1) Water absorption Rate = -0.1344 (A)-0.6148 (B) + 0.00432 (C)-3.4652 (D)-3.3566 (E) + 0.3814 (J) + 0.3543 (K) + 29.043… (5-2) Crush strength = 0.3290 ( A) +3.4795 (B) -0.02216 (C) +0.6300 (D) +52.586 (E) -1.6938 (J) -0.6931 (K) +32.630… (5-3) Water content = -0.09317 (A) -0.1510 (B) +0.006617 (C) +1.2601 (D) +25.734 (E) +0.02857 (J) +0.2657 (K) -19.397… (5-4) Crush strength = -0.00581 (A) +0.01144 (B)- 0.00018 (C) +0.01149 (D) -0.3846 (E) +0.01505 (J) +0.00848 (K) +0.8166… (5-5) Drop resistance = 0.00885 (A) +0.10082 (B) -0.00136 (C) + 0.2658 (D) -1.5384 (E) +0.08524 (J) +0.02738 (K) +2.3177… (5-6) Apparent specific gravity = 0.009524 (A) -0.03395 (B) +0.0006052 (C) +0.20099 (D) +1.7569 (E) +0.007810 (J) -0.004905 (K) -1.7854… (5-7)

On the other hand, as shown in FIG. 1, the facility for producing an artificial lightweight aggregate is provided with a classifier 11 for classifying coal ash by air sorting. The classifier 11 is provided with a rotating body that rotates each particle of the coal ash to give a centrifugal force due to the rotational flow and a drag force due to the air flow to each particle, and blows the coarse particles toward the outer periphery of the rotating body by the centrifugal force. By sending the fine particles together with air in the inner circumferential direction of the rotating body, both particles are selected. Then, the classifier 11 arbitrarily changes the rotation speed of the rotating body so as to classify the coal ash into coarse powder in which the weight ratio of the fine particles having a particle size of 10 μm or less is equal to or less than a predetermined value and other fine powder. Has been enabled. .

Here, when classifying coal ash, a particle size of 10
The reason for paying attention to the fine particles having a particle size of μm or less is that if there are many fine powders in the coarse powder, the fine powder enters between the coarse powders and fills the voids. Also, the amount of fine powder having a particle size of 10 μm or less greatly affects the absolute specific gravity, and even if the amount of fine powder having a particle size of more than 10 μm is specified, the absolute dry specific gravity does not change so much.
Furthermore, the classification efficiency when classifying coal ash is 10 μm in particle size.
If the ratio exceeds the limit, the efficiency of collecting the coarse powder is reduced, and the fine powder and the coarse powder cannot be separated. Especially in the case of coal ash, the fine powder is J
Since it can be sold as IS ash, it is necessary to separate fine particles having a particle size of 10 μm or less in order to set the selection ratio between coarse powder and fine powder within 50% ± 20%.

Classifier 11 for classifying coal ash as described above
The outlet 11a for coarse powder containing fine particles is connected to the first hopper 1 of the pellet forming system 43. The pellet forming system 43 includes first to fifth hoppers 1a to 1e, a kneader 5, a crusher 6, a belt feeder 7, and a bread granulator 8 in this order from the upstream side. The first hopper 1a temporarily stores the coal ash sent from the classifier 11. Further, the second to fifth hoppers 1b to 1e are connected to the first hopper 1
a. These second to fifth hoppers 1b
1e contain heavy oil ash, sewage sludge incineration ash, fluidized bed boiler ash, and perlite as fillers, respectively.
In addition, a filler means the material which reduces absolute dry specific gravity. And these first to fifth hoppers 1a to 1e
The supply ports at the lower end are connected to each other, so that coal ash and filler are mixed at an arbitrary ratio, and this mixture can be supplied to the kneading machine 5 at the subsequent stage.

Here, heavy oil ash, sewage sludge incineration ash, and fluidized bed boiler ash are used as low specific gravity agents.
As the low specific gravity agent, a substance whose true specific gravity or apparent specific gravity is lighter than coal ash which is a main raw material, or any substance containing a component which burns and burns out can be used. Common low-specific-gravity agents include chaff, sawdust, chute, bacass, coal grains, coke grains, charcoal grains, wood chips, and crushed paper.

The low-specific-gravity agent is a fluid-bed boiler ash or sewage-sludge incineration ash that is disposed of as landfill because of its low availability and high cost. It is preferable to effectively use at least one of construction mud and heavy oil ash that contains residual carbon. Sewage sludge incineration ash is a residue generated when burning sludge generated in a sewage treatment plant, and construction mud is waste mainly composed of earth and sand generated in construction and civil engineering work. Fluid bed boiler ash is a residue of coal burned in a fluid bed boiler, and heavy oil ash is a residue generated when burning heavy oil. In particular, fluidized-bed boiler ash alone is not a lightweight aggregate and has more residual carbon than coal ash, so it is suitable for mixing with coal ash to lower the absolute dry specific gravity. However, waste-based low-specific-gravity agents such as fluidized-bed boiler ash mixed with 100 parts by weight of coal ash are mixed up to 40 parts by weight. If the amount exceeds 40 parts by weight, the yield rate at the time of sintering is deteriorated due to the decrease in crushing strength, and the decrease in specific gravity of absolutely dry is reduced.

The above-mentioned pearlite is used as a foaming agent. As the foaming agent, besides perlite, at least one or more of foamable minerals such as shirasu and zeolite and gypsum can be used. Shirasu, perlite and zeolite are naturally occurring minerals, and gypsum may be any of industrial products or those generated in a desulfurization process. The foaming agent is not limited to the above-mentioned materials, and may be any material that exhibits foaming properties in a high temperature range of 800 ° C. or higher. However, the amount of the foaming agent mixed with the coal ash is limited to 20 parts by weight with respect to 100 parts by weight of the coal ash or the coal ash and the low specific gravity agent. This is because even when the amount exceeds 20 parts by weight, a decrease in the absolute specific gravity is not observed.

A kneader 5 is disposed downstream of the first to fifth hoppers 1a to 1e containing various additives and coal ash as described above. The kneading machine 5 is configured to add water 5 ′ to coal ash or a mixture of coal ash and a filler and knead the mixture. The kneader 5 is connected to a crusher 6 for crushing the mixture, and the crusher 6 is connected to a bread granulator 8 via a belt feeder 7. The bread granulator 8 is set so as to form the mixture from the crusher 6 as raw pellets 65 having a predetermined particle size.

The above-mentioned pan-type granulator 8 is connected to a self-combustion-type linear moving sintering machine 12 using a grate.
The linear moving sintering machine 12 is configured to sinter the raw pellets 65 supplied from the pan-type granulator 8 by performing a drying-ignition-sintering-cooling process by a continuous operation.

That is, the firing machine 12 comprises an endless grate 21 which moves in the horizontal direction (arrow A in the figure) and this grate 21.
Of the drying / preheating furnace 22, the ignition furnace 23 and the sintering / heat preserving furnace 24, the hot air tube 28 for feeding high-temperature air to each furnace 22, 23/24, and the sintering / heat preserving furnace 24. And a cooling zone 29 provided on the downstream side. Below the grate 21, a wind box 25 having an upper end opened toward the grate 21 is provided. The lower end of the wind box 25 is connected to a suction side of a blower 27 through an exhaust duct 26. ing. And
A chute 30 for leading out a sintered body of the raw pellets 65 generated by the firing machine 12 and a crusher 31 for separating the sintered body are provided downstream of the linear moving firing machine 12 configured as described above. And a sieving machine 32 for sifting the sintered body into product pellets having a predetermined shape.

A method for manufacturing an artificial lightweight aggregate having the above structure will be described. First, before manufacturing an artificial lightweight aggregate using coal ash, optimum manufacturing conditions for obtaining a desired artificial lightweight aggregate are determined using a property prediction device.

That is, as shown in FIG. 2, for the property prediction device executing the pellet property prediction routine, “average particle size of coal ash” and “less than 10 μm” are used as the coal ash property parameters used in the prediction formula. Each data of "% by weight of fine particles", "specific surface area", "true specific gravity", "closely packed bulk density", and "alkalinity" is input (S1).

Next, it is determined by the operator whether to manufacture the artificial lightweight aggregate using only the coal ash or to mix the coal and the filler, and if the manufacturing is performed using only the coal ash, the plain ash is used. A prediction formula is selected. In the case where pearlite is used as the filler because it is a mixture of coal properties and a filler, a pearlite addition prediction formula is selected. Similarly,
A heavy oil ash addition prediction formula, a sewage sludge incineration ash addition prediction formula, and a fluidized bed boiler ash / incineration ash addition prediction formula are selected depending on the type of the filler (S2).

When the prediction formula is selected as described above,
If a prediction formula other than the simple ash prediction formula is selected, the filler property parameters corresponding to each prediction formula, such as “perlite weight%”, “heavy oil ash weight%”, and “incineration ash Data of "% by weight", "% by weight of fluidized bed boiler ash", and "% by weight of incinerated ash" are input (S3). And
By substituting the coal ash property parameter and filler property parameter data into the selected prediction formula, the properties of the sintered pellet, such as the absolute dry gravity, and the properties of the raw pellet, such as the moisture content, are determined and displayed. It is displayed (S4). Thereafter, the properties of the sintered pellets displayed on the screen are confirmed by the operator, and the operator determines whether or not to change the data of the filler property parameters (S5). If it is to be changed (S5, YES), S3 is executed again, and the data of the filler property parameter is input again. On the other hand, when the data of the filler property parameter is not changed (S5, NO), it is subsequently determined whether to change the data of the coal ash property parameter (S6). And when it changes (S6, YES), S2 is executed again,
Data input of the coal ash property parameters is performed again.

On the other hand, when the data of the coal ash property parameter is not changed (S6, NO), it is determined whether to change the prediction formula (S7). When changing the prediction formula (S7, YES), S1 is executed again, and a prediction formula is selected. On the other hand, when the prediction formula is not changed (S7,
NO), this routine ends.

If the simple ash prediction formula is selected in S2, the properties of the sintered pellet such as the absolute dry specific gravity are substituted by substituting the data of the coal ash property parameters into the simple ash prediction formula. And properties such as the moisture content of the raw pellets are determined and displayed on the screen (S4). Thereafter, S6 and S7 are executed, and the data of the coal ash property parameter and the prediction formula can be changed by the same operation as described above, and then this routine is ended.

When the desired property of the sintered pellet is obtained by the property predicting apparatus as described above, the property of the raw pellet calculated simultaneously with the sintered pellet is confirmed. Then, production conditions are determined based on the properties of the raw pellets, and the operation of the production equipment in FIG. 1 is set.

When the setting of the manufacturing conditions for the manufacturing equipment is completed, the coal ash stored in a pit (not shown), which is the basis for calculating the above-mentioned prediction formula, is sent to the classifier 11. Then, in the classifier 11, as the coal ash is rotated, each particle of the coal ash is given a centrifugal force due to the rotational flow and a drag force due to the air flow. Thereby, while the coarse particles of the coal ash are blown outward by the centrifugal force, the fine particles of the coal ash are sent in the inner circumferential direction together with the air, whereby the coal ash is sorted (classification step). Then, when the coal ash, which is a coarse powder in which the weight ratio of the fine particles having a particle diameter of 10 μm or less occupies a predetermined value or less, is obtained by classification, the coal ash is sent from the delivery port 11a to the first hopper 1 at the subsequent stage.

Next, coal ash is supplied to the kneader 5 from the first hopper 1. The filler is fed to the kneader 5 from the second to fifth hoppers 1b to 1e as needed. Then, water 5 'is injected by the kneading machine 5, and the coal ash and the filler are kneaded. This kneaded material is crushed in the crusher 6,
It is supplied to the bread-type granulator 8 at a constant supply amount by the belt feeder 7. Then, after being formed into raw pellets 65 having a predetermined particle size in the bread type granulator 8, the linear moving firing machine 1 is used.
2 (raw pellet forming step).

The raw pellets 65 fed to the linear moving firing machine 12 are sintered through a drying-ignition-firing-cooling process. That is, the raw pellets 65 are supplied in a fixed amount onto the grate 21, and when the raw pellets 65 move along with the grate 21 and pass through the furnaces 22, 23, 24, the hot air is supplied from the hot air tube 28. The raw pellets are supplied and sucked downward by the blower 27 toward the lower side of the raw pellet (arrow B in the figure). Note that sintered pellets are laid for the floor of the raw pellets 65. Then, sintering is performed by the high-temperature air. Specifically, the raw pellets 65 are dried and dried by the preheating furnace 22.
Is dried, and then the dried pellets 6
Unburned coal in 5 'ignites. Further, the burning of the unburned coal in the dry pellets 65 'is shifted downward by the sintering / heating furnace 24, and the entire sintering is completed to form sintered pellets 65''(firing step).

Thereafter, the sintered pellet 65 ″ is conveyed to the cooling zone 29, and a part of the suction air of the blower 27 passes downward through the layer of the sintered pellet 65 ″ (arrow C in the figure). Thus, the sintered pellet 65 ″ is cooled. The pellet mass of the cooled sintered pellet 65 ″ is sent to the crusher 31 via the chute 30 and separated. Then, the separated sintered pellet 6
5 ″ is sieved into product pellets having a predetermined shape by the sieving machine 32 to obtain an artificial lightweight aggregate having a specific gravity of 1.25 or less.

Incidentally, the coefficients of the respective prediction equations in the present embodiment were obtained based on the test results in Tables 1 to 5. That is, as shown in Table 1, the simple ash prediction formula measures the properties of coal ash, raw pellets, and sintered pellets when 17 types of coal ash samples are actually prepared as sintered pellets. Then, these measurement data were created by multiple regression.

[0044]

[Table 1]

As shown in Table 2, the pearlite addition prediction formula measures the coal ash properties, raw pellet properties, and sintered pellet properties of 14 types of coal ash samples when sintered pellets were actually prepared. Then, these measurement data were created by multiple regression.

[0046]

[Table 2]

The prediction formula for heavy oil ash addition is as shown in Table 3,
Coal ash properties, raw pellet properties, and sintered pellet properties when actually producing sintered pellets for 11 types of coal ash samples were measured, and these measurement data were prepared by multiple regression.

[0048]

[Table 3]

The prediction formula for heavy oil ash addition is as shown in Table 4.
Coal ash properties, raw pellet properties, and sintered pellet properties when actually producing sintered pellets for 12 types of coal ash samples were measured, and these measurement data were prepared by multiple regression.

[0050]

[Table 4]

The formula for predicting the addition of fluidized bed boiler ash and incinerated ash is as follows:
As shown in Table 5, coal ash properties, raw pellet properties, and sintered pellet properties when actually producing sintered pellets for eight types of coal ash samples were measured, and these measurement data were subjected to multiple regression. Created.

[0052]

[Table 5]

[0053]

According to the first aspect of the present invention, coal ash is classified.
A coarse powder containing fine particles having a particle size of 10 μm or less is formed, the coarse powder is granulated to form a raw pellet, and then the raw pellet is fired to form a sintered pellet, whereby a desired artificial lightweight aggregate is obtained. A method for producing an artificial lightweight aggregate to be produced, wherein the properties of the sintered pellets are obtained by a sintered pellet property prediction formula composed of coal ash property parameters indicating the properties of the coal ash, and the same coal ash properties are obtained. The properties of the raw pellets were determined by a raw pellet property prediction formula composed of parameters, and the coal ash was used based on the properties of the raw pellets when the properties of the sintered pellets became a desired artificial lightweight aggregate. This is a configuration for obtaining the manufacturing conditions of the artificial lightweight aggregate.

According to the above configuration, since the properties of the sintered pellets and the raw pellets are obtained by the sintered pellet property prediction formula and the raw pellet property prediction formula composed of the same coal ash property parameters, respectively, When the property of the pellet is a desired artificial lightweight aggregate, the property of the raw pellet in the intermediate stage before the sintered pellet can be obtained. As a result, since the manufacturing conditions can be obtained based on the properties of the raw pellets, it is possible to eliminate the reduction in yield and the burden on the operator as in the case of obtaining the manufacturing conditions by performing trial manufacture and inspection. Play.

According to a second aspect of the present invention, the coal ash is classified into coarse powder containing fine particles having a particle size of 10 μm or less, and the coarse powder and the filler are mixed and granulated to form raw pellets. A method for producing an artificial lightweight aggregate for producing a desired artificial lightweight aggregate by firing the raw pellet to form a sintered pellet, wherein coal ash property parameters indicating properties of the coal ash, While obtaining the properties of the sintered pellets by a sintered pellet property prediction formula composed of filler property parameters indicating the properties of the filler, raw pellets composed of the same coal ash property parameters and filler property parameters Determine the properties of the raw pellets by a property prediction formula,
The production conditions of the artificial lightweight aggregate using the coal ash are determined based on the properties of the raw pellets when the properties of the sintered pellets become the desired artificial lightweight aggregate.

According to the above configuration, the properties of the sintered pellets and the raw pellets are obtained by the sintered pellet property prediction equation and the raw pellet property prediction equation composed of the same coal ash property parameters and filler property parameters, respectively. Therefore, when the property of the sintered pellet is a desired artificial lightweight aggregate, the property of the raw pellet in the intermediate stage before the sintered pellet can be obtained. This allows the production conditions to be determined based on the properties of the raw pellets,
As a result, it is possible to eliminate the reduction in yield and the burden on the operator, which is the case when the production conditions are obtained by performing trial manufacture and inspection.

[Brief description of the drawings]

FIG. 1 is a process diagram of a facility for manufacturing an artificial lightweight aggregate.

FIG. 2 is a flowchart of a pellet property prediction routine.

[Explanation of symbols]

 1a to 1e 1st to 5th hoppers 5 Kneader 6 Crusher 7 Belt feeder 8 Bread granulator 11 Classifier 12 Linear moving firing machine 43 Pellet forming system 65 Raw pellet

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Jiro Terokina 4-3-1, Bingo-cho, Chuo-ku, Osaka-shi, Osaka Prefecture Kobe Steel, Ltd. Osaka branch office (72) Inventor Kazunobu Exit Bingo, Chuo-ku, Osaka-shi, Osaka 4-3-1, Komachi Kobe Steel, Ltd. Osaka Branch Office (72) Inventor Masaji Abe 2109-8 Yashima Nishimachi, Takamatsu City, Kagawa Prefecture Techno Resources Corporation Headquarters (72) Inventor Kyoya Tamura Takamatsu, Kagawa Prefecture 2109-8, Ichiyajima-Nishimachi Techno-Resource Co., Ltd. (72) Inventor Tokuji Akiba 2-2-5 Yanaka, Taito-ku, Tokyo (72) Inventor Masami Kato Morigo Shinoda, Miwa-cho, Kaifu-gun, Aichi Prefecture 78 F term (reference) 4D004 AA36 BA02 CA04 CA08 CA14 CA15 CA30 CA45 DA03 DA20

Claims (2)

[Claims] 1. Classifying coal ash into coarse powder containing fine particles having a particle size of 10 μm or less, granulating the coarse powder to form a raw pellet, and firing the raw pellet to form a sintered pellet. A method for manufacturing an artificial lightweight aggregate by forming a desired artificial lightweight aggregate, wherein the sintering is performed by a sintered pellet property prediction formula composed of coal ash property parameters indicating properties of the coal ash. The properties of the pellets are determined, and the properties of the raw pellets are determined by a raw pellet property prediction formula composed of the same coal ash property parameters, and the properties of the sintered pellets are changed to a desired artificial lightweight aggregate. A method for producing an artificial lightweight aggregate, wherein the conditions for producing the artificial lightweight aggregate using the coal ash are determined based on the properties of the pellet. 2. Classifying the coal ash into a coarse powder containing fine particles having a particle size of 10 μm or less, mixing and granulating the coarse powder and a filler to form a raw pellet, and then firing the raw pellet. Forming a sintered pellet to produce a desired artificial lightweight aggregate, a method for producing an artificial lightweight aggregate, the coal ash property parameters indicating the properties of the coal ash, and the properties of the filler The properties of the sintered pellets are obtained by a sintered pellet property prediction formula composed of the filler property parameters shown and the raw pellet property prediction formula composed of the same coal ash property parameter and filler property parameter. The properties of the raw pellets are determined, and the manufacturing conditions of the artificial lightweight aggregate using the coal ash are determined based on the properties of the raw pellets when the properties of the sintered pellets become the desired artificial lightweight aggregate. Process for producing an artificial lightweight aggregate, wherein the door.