JPH0676241B2 - Low heat cement clinker manufacturing equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a low heat-generating cement clinker suitable for use in underground structures, bridges, dam construction, etc., and particularly to fluidized bed granulation furnaces and fluidized bed firing. The present invention relates to a low heat-generating cement clinker manufacturing device using a furnace, a primary fluidized bed cooling device, and a secondary fluidized bed cooling device.

"Conventional technology and its problems" Low heat cement is FC, MFC, KC-specified in JIS.
B, blast furnace cement for dam, ASTM type II or special mixed cement, etc., but all of them have a limitation in mineral composition because they burn cement clinker in a rotary kiln. In other words, 3CaO for low heat cement clinker
It is necessary to reduce SiO ₃ (C ₃ S) and 3CaO ・ Al ₂ O ₃ (C ₃ A), but since it contributes to cement clinker mineral formation as a high temperature liquid phase inside the rotary kiln, C ₃ A is eliminated. It was impossible to manufacture cement clinker with the above mineral composition due to the coating adhesion in the kiln. In addition, no study has been made on a composition with low C ₃ A content in terms of the low exothermic semmet mineral composition. AQC also for cement clinker cooling
With (air quenching cooler), it is difficult to secure the cooling rate and the quality of the cement clinker.

By the way, in the conventional method for producing low heat-generating cement, when it is produced by the rotary kiln as described above, C ₃ A or 4CaO ・ Al ₂ O ₃・ Fe ₂ O ₃ (C ₄ AF) + 2CaO ・ Fe ₂ O in the clinker mineral is used.
It is completely impossible to manufacture by significantly reducing the content of ₃ (C ₂ F), especially the content of C ₃ A, due to the adhesion of coating in the rotary kiln, etc. C ₃ A in heat-generating cement clinker is 3
I had to make it more than%. Therefore, in this case, the calorific value (heat of hydration cal / g) of the produced low exothermic cement was extremely high, and the practical value was low. Furthermore, the C ₃ A in the low heat cement clinker is produced in rotary kiln good low heat cement 3% or less is completely impossible, C ₃ of low heat cement clinker minerals
There was no technology in the world that could reduce A to 3% or less.

In addition, the C ₂ S content in conventional low heat-generating cement clinker minerals is extremely high at about 70%, and since the content of γ-C ₂ S is extremely large because it is fired in a rotary kiln and then gradually cooled, the cement clinker The amount of γ-C ₂ S, which is the main cause of dusting, was significantly generated and the quality of the low heat-generating cement clinker produced was significantly reduced.

The present invention has been made to improve the above points,
Cement clinker Increases the strength of the low heat generation cement clinker produced by adding gypsum, reduces the heat of hydration, and enables stable and continuous production of the low heat generation cement clinker with less dusting and stable quality. Another object of the present invention is to provide a production apparatus capable of producing a low heat-generating cement clinker in which the heat of hydration reaction of cement clinker is significantly reduced and the mortar compressive strength is increased.

[Means for Solving the Problem] In the low heat-generating cement clinker manufacturing apparatus of the present invention, the content of 3CaO.Al ₂ O _{3 in} the cement clinker mineral is 0 to 2%.
And a suspension preheater for preheating low-heat-generating cement raw material powder, which is compounded so that the total content of 4CaO ・ Al ₂ O ₃・ Fe ₂ O ₃ and 2CaO ・ Fe ₂ O ₃ is 7 to 20%. And a spouted bed granulation furnace connected to this suspension preheater for granulating preheated cement raw material powder, a fluidized bed firing furnace connected to this spouted bed granulation furnace through an exhaust gas duct and an airtight discharge device, and this flow 3CaO in cement clinker mineral consisting of a cooling device connected to a layer firing furnace to cool the fired product
Al ₂ O ₃ content is 0 to 2%, and 4CaO ・ Al ₂ O ₃・ Fe
In ₂ O ₃ and total manufacturing apparatus low heat cement clinker content of 7-20 percent of the 2CaO · Fe ₂ O _3, constitutes a cooling device in the primary fluidized bed cooling device and the secondary cooling device The upper part of the primary fluidized bed cooling device and the freeboard part of the fluidized bed firing furnace are connected via an exhaust gas duct, and the vicinity of the interface between the upper side of the fluidized bed of the fluidized bed firing furnace and the fluidized bed of the primary fluidized bed cooling device Are connected via an overflow discharge chute so that the fired cement clinker is discharged by overflowing, the primary fluidized bed cooling device and the secondary cooling device are connected via an airtight discharge device, and The upper part and the wind of the fluidized bed firing furnace are connected via an exhaust gas duct, and 3C in the cement clinker mineral is connected.
The content of aO ・ Al ₂ O ₃ is 0-2%, and 4CaO ・ Al ₂ O ₃
- The total content of Fe ₂ O ₃ and 2CaO · Fe ₂ O ₃ is that it has to produce low calorific cement clinker from 7 to 20 percent as means for solving the above-described problem.

"Working" Thus, the present invention is C ₃ A0 to in the cement clinker minerals
2%, preferably 0 to 1%, the total of C ₄ AF + C ₂ F is 7 to 20
%, Preferably 12-18%, of a low heat-generating cement raw material is fired in a fluidized bed firing furnace, and the upper side of the fluidized bed of the firing furnace and the vicinity of the interface between the fluidized bed of the primary fluidized bed cooling device. The low heat-generating cement clinker that has been fired in the fluidized bed is rapidly cooled to 1000 ° C to 1100 ° C by passing through an overflow discharge chute provided with a water cooling jacket so that the low heat-generating cement clinker overflows and is discharged. It is not changed mainly due serving γ-C ₂ S dusting is exhausted, γ-C ₂ S is decreased significantly, made the low heat cement clinker good quality, yet C ₃ a is 0-2% It is possible for the first time to preferably set 0 to 1% and the total of C ₄ AF + C ₂ F to 7 to 20%, preferably 12 to 18%, and set C ₃ A to 0.
It is extremely small at ~ 2%, and in order to make the total of C ₄ AF + C ₂ F 7 to 20%, it was impossible to produce good quality low heat-generating cement by the conventional rotary kiln technology due to the coating adhesion problem in the kiln. The fluidized bed technology of the present invention (particularly using a quench chute) makes it possible for the first time to produce an extremely high quality low heat-generating cement with a 10% increase in compressive strength and a 10% decrease in calorific value.

[Examples] Hereinafter, preferred examples of the present invention will be described in detail with reference to the drawings. However, the shape of the components described in this embodiment, the relative arrangement, and the like, unless otherwise specified, are not intended to limit the scope of the present invention to only those, and are merely illustrative examples. Only.

[Example 1] As shown in Fig. 1, a device for producing a low heat-generating cement clinker of the present example has a suspension preheater (preheater) 3 for preheating low-heat-generating cement raw material powder, and a low heat generating device connected to this suspension preheater. A spouted bed granulating furnace 1 for granulating preheated cement raw material powder, a fluidized bed calcining furnace 2 connected to this spouted bed granulating furnace via an exhaust gas gact 13 and an airtight discharge device 7, and this fluidized bed calcining furnace In a low heat-generating cement clinker manufacturing apparatus including a cooling device connected to cool a fired product, the cooling device is configured by a primary fluidized bed cooling device 20 and a secondary fluidized bed cooling device 21, and a temporary fluidized device cooling device 20 Is connected to the freeboard portion 22 of the fluidized bed firing furnace 2 via exhaust gas dust 23, and the upper side of the fluidized bed of the fluidized bed firing furnace 2 and the vicinity of the interface of the fluidized bed of the primary fluidized bed cooling device 20 are connected. , Low heat firing The ment clinker is connected via an overflow discharge chute 24 so that the ment clinker can be discharged by overflow, the primary fluidized bed cooling device 20 and the secondary fluidized bed cooling device 21 are connected via an airtight discharge device 25, and the secondary Fluidized tank cooling device 21
And an air box 26 of the fluidized bed firing furnace 2 are connected via an exhaust gas duct 27. 28 is a burner, 30, 31,
32 is an air dispersion plate, 33 is a pushing fan, and 34 is a partition plate. Although the secondary fluidized bed cooling device 21 is shown as a multi-chamber type, it is not limited to this and may be another type such as a single chamber. Further, the cooling device is not limited to the fluidized bed cooling device, and may be another type of cooling device such as a packed bed cooler.

In the low heat-generating cement clinker manufacturing apparatus configured as described above, the suspension preheater (preheating section) 3
The cement raw material powder preheated in (1) is charged into the spouted bed granulation furnace 1 and granulated. The low heat-generating cement raw material that has not been granulated in the spouted bed granulation furnace 1 is returned to the spouted bed granulation furnace 1 again via the cyclone C ₁ .

The granulated material that has accumulated and grown in the spouted bed granulation furnace 1 is discharged to the fluidized bed firing furnace 2 by the airtight discharge device 7, and there again.
It is baked at 1400-1450 ° C. The fired cement clinker is instantaneously cooled by overflow and is discharged to the primary fluidized bed cooling device 20.

In the primary fluidized bed cooling device 20, the cement clinker is rapidly cooled in the range of 1000 to 1100 ° C. The primary cooled cement clinker is discharged to the secondary fluidized bed cooling device 21 via the airtight discharge device 25, and is sequentially cooled while overflowing the partition plate 34 in the secondary fluidized bed cooling device.

In the primary fluidized bed cooling device 20, the high-temperature cooling air that has exchanged heat with the calcined low heat-generating cement clinker is discharged into the exhaust gas duct 23.
And is introduced into the freeboard portion 22 of the fluidized bed firing furnace 2 through the overflow discharge chute 24 and mixed with the fluidized bed firing furnace exhaust gas to lower the temperature of the fluidized bed firing furnace exhaust gas.

As a result, the wall surface temperature of the freeboard portion 22 of the fluidized bed firing furnace 2 is lowered, so that the high temperature low heat generation cement clinker small particles that have jumped out of the fluidized bed of the fluidized bed firing furnace 2 do not adhere to the wall surface. .

Example 2 As shown in FIG. 1, the apparatus for producing a low heat-generating cement clinker of this example controls a bed pressure loss by connecting a bed pressure loss measuring device to the fluidized bed of the primary fluidized bed cooling device 20. The bed pressure drop measuring device is used so that the calcined cement clinker is supplied on the interface of the fluidized bed.
35 and an air supply valve 36 of the airtight discharge device 25 of the primary fluidized bed cooling device 20 are connected via an arithmetic unit 37.

In this way, the bed pressure loss of the primary fluidized bed cooling device 20 is controlled by adjusting the discharge amount of the airtight discharge device 25, and the discharged cement clinker from the fluidized bed firing furnace 2 is controlled by the primary fluidized bed cooling device. Be constantly fed over 20 fluidized bed interfaces. Other configurations and operations are similar to those of the first embodiment.

[Embodiment 3] As shown in FIGS. 1 and 5, the apparatus for manufacturing a low heat-generating cement clinker of this embodiment is provided with a water cooling jacket 38 in the overflow discharge chute 24 of the fluidized bed firing furnace 2 and A variable draft resistance device 40 such as a variable throttle is provided in the overflow discharge chute 24 on the downstream side. 41
Is a fluidized bed cooling device, for example, a primary fluidized bed cooling device as shown in FIG. 1 is used. 42 is a burner, 43 and 44 are wind boxes, 45 discharge weirs, and 46 is a granule input port.

As described above, in this example, in order to reduce the flow velocity of the gas flowing from the fluidized bed cooling device 41 to the fluidized bed firing furnace 2 in the overflow discharge chute 24, the water cooling jacket 38 is moved toward the cooling device side, for example, a vertically movable variable. By providing a variable ventilation resistance such as a diaphragm, even small particles can be easily discharged.

[Example 4] In the fluidized bed firing furnace 2 of this example, as shown in Figs. 2 to 5, an overflow discharge chute 24 is connected to the side wall of the furnace body above the fluidized bed, and the inlet of this overflow discharge chute is connected. An overflow weir 45 is provided in the portion, a water cooling jacket 38 is provided in the overflow discharge chute 24 adjacent to this weir, and the lower end of the overflow discharge chute 24 is connected to the fluidized bed cooling device 41 near the bed interface.

The granulated material supplied to the fluidized bed firing furnace 2 is mixed with the particles in the fluidized bed and is fired at a temperature of 1400 to 1450 ° C while staying. The burned cement clinker overflows the weir 45 and is transferred into the discharge chute 24.

However, since the water cooling jacket 38 is provided adjacent to the weir 45, the high temperature adhesive cement clinker particles that have overflowed the weir 45 contact the water cooling jacket 38 and immediately contact the surface of the cement clinker particles. To be cooled. As a result, the particles lose their tackiness and the discharge chute 24
It is transferred to the fluidized bed cooling device 41 without adhering to the inner wall.

Further, since the low heat-generating cement clinker supply decay 47 of the fluidized bed cooling device 41 is provided in the vicinity of the layer interface, the low heat-generating cement clinker particles are not filled in the discharge chute 24, and therefore the moving bed is There is no formation, and the low heat-generating cement clinker particles are smoothly supplied into the cooling device 41.

Therefore, the particles do not adhere to the wall surface in the discharge chute 24 and do not adhere to each other, and the low heat-generating cement clinker is smoothly transferred from the fluidized bed firing furnace 2 to the cooling device.

As described above, since the moving bed is not formed in the discharge chute 24, the cement clinker is instantaneously discharged into the cooling device 41. Therefore, the cement clinker is rapidly cooled from the temperature level of 1400 to 1450 ° C to the temperature level of 1000 to 1100 ° C, and a high quality low heat-generating cement clinker can be manufactured.

[Fifth Embodiment] In the fluidized bed firing furnace 2 of the present embodiment, as shown in Figs. 3 and 4, the vertical discharge chute portion 48 is adjacent to the overflow weir 45.
And a water cooling jacket 38 is provided adjacent to the downstream side of the vertical discharge chute.

The cement clinker particles transferred from the fluidized bed firing furnace 2 into the discharge chute 24 first fall by gravity on the vertical discharge chute section 48. For this reason, the cement clinker particles have an inertial force, roll in the discharge chute 24, and can be smoothly discharged. Other configurations and operations are similar to those of the fourth embodiment.

[Example 6] In the fluidized bed firing furnace 2 of this example, as shown in Figs. 2 to 5, the inlet 46 of the granulated material into the fluidized bed firing furnace 2 is located below the upper end of the overflow weir 45. It was installed in. Therefore, the granulated material charged into the fluidized bed firing furnace 2 does not stay in the bed of the fluidized bed firing furnace and immediately overflows the discharge chute.
It is no longer discharged to the 24 outlets. Other configurations and operations are similar to those of the fourth embodiment.

[Example 7] Using the starting materials of the low heat-generating cement shown in Table 1, these were mixed in the following compounding ratios to obtain a low heat-generating cement clinker by the manufacturing apparatus shown in the first embodiment. The firing was performed in an electric furnace at 1420 ° C for 30 minutes.

This clinker was analyzed by JIS method, and the results are shown in Table 2.

As shown in Table 2, the obtained clinker did not have C ₃ A, and C ₄ AF + C ₂ F was 12 to 18%.

[Example 8] Using a clinker separately obtained by the compounding and manufacturing method of Example 7, the mortar compressive strength and the heat of hydration were measured. The chemical composition of the clinker is shown in Table 3, and the mineral composition of the clinker, the mortar compressive strength and the heat of hydration are shown in Table 4. For comparison, the conventional ordinary cement clinker is also shown.

Here, the conventional product 3 is manufactured by a rotary kiln.

As can be seen from Table 4, the product of the present invention had C ₃ A of zero and C ₄ AF of + C ₂ F of 14.3%. In addition, this product was superior to the conventional product in both mortar compressive strength and heat of hydration.

[Example 9] A low heat-generating cement clinker of the present invention was obtained in the same manner as in Example 8, the chemical composition of the clinker is shown in Table 5, the mineral composition of the clinker and the mortar compressive strength and the heat of hydration are shown in Table 6. Indicated. For comparison, the conventional ordinary cement clinker is also shown.

As can be seen from Table 6, the product of the present invention is superior to the conventional product in both mortar compressive strength and heat of hydration as in Example 8.

Apparatus for producing a low heat cement clinker of the present invention as has been described, "Effect of the Invention" because it has to obtain those containing little C ₃ A, low heat cement clinker obtained is cement hydration reaction heat Significantly reduced, mortar strength is also higher than conventional products.

In addition, since the cement clinker is fired in the fluidized bed from the rotary kiln, the cement clinker having a clinker mineral composition containing no C ₃ A can be fired.

Furthermore, since the burned cement clinker is made into an overflow type from the fluidized bed firing furnace and rapidly cooled and discharged to the fluidized bed cooler, high quality of the cement clinker can be secured.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a low heat-generating cement clinker manufacturing apparatus of the present invention, FIG. 2 is a sectional view of a fluidized bed firing furnace in the manufacturing apparatus shown in FIG. 1, FIG. 3 and FIG. FIG. 5 is a sectional view showing another example of the fluidized bed firing furnace, and FIG. 4 is an enlarged sectional view taken along the line AA in FIG. C ₁ -C ₄ ...... cyclone, 1 ...... spouted bed granulating furnace, 2 ...... fluidized bed sintering furnace, 3 ...... suspension preheater (preheating section) 7 ...... airtight discharge device, 13,23,27 ...... exhaust gas Duct, 20 …… Primary fluidized bed cooling device, 21 …… Secondary fluidized bed cooling device, 22 …… Freeboard part, 24 …… Overflow discharge chute, 25 …… Airtight discharge device, 26 …… Wind box,

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuo Igarata 3-7-5-105 Tsudanuma, Narashino City, Chiba Prefecture (72) Inventor Yoshikazu Matsuoka 813 Hinoguchi, Matsudo City, Chiba Prefecture

Claims (1)

[Claims] 1. A content of 3CaO · Al ₂ O ₃ in the cement clinker minerals is 0-2%, and _{4CaO · Al 2 O 3 · Fe} 2 O 3 and 2Ca
A suspension preheater (3) that preheats the low heat-generating cement raw material powder blended so that the total content of O and Fe ₂ O ₃ is 7 to 20%, and the preheated cement raw material powder that is connected to this suspension preheater. A spouted bed granulation furnace (1) for granulation, a fluidized bed firing furnace (2) connected to this spouted bed granulation furnace via an exhaust gas duct (13) and an airtight discharge device (7), and this fluidized bed 3CaO in cement clinker mineral consisting of a cooling device connected to a firing furnace to cool the fired product
Al ₂ O ₃ content is 0 to 2%, and 4CaO ・ Al ₂ O ₃・ Fe ₂
In a low heat-generating cement clinker manufacturing apparatus having a total content of O ₃ and 2CaO / Fe ₂ O ₃ of 7 to 20%, the cooling device is a primary fluidized bed cooling device (20) and a secondary cooling device (21 ) And the upper part of the primary fluidized bed cooling device and the fluidized bed firing furnace (2)
Is connected to the freeboard section (22) of the same through the exhaust gas duct (23), and the upper side of the fluidized bed of the fluidized bed firing furnace (2) and the vicinity of the interface of the fluidized bed of the primary fluidized bed cooling device are fired cement clinker Are connected via an overflow discharge chute (24) so as to be discharged by overflowing, and the primary fluidized bed cooling device (20) and the secondary cooling device (21) are connected to the airtight discharging device (25).
, The upper part of the secondary cooling device and the wind (26) of the fluidized bed firing furnace are connected through the exhaust gas duct (27), and the content of 3CaO ・ Al ₂ O ₃ in the cement clinker mineral is increased. 0-2%
, And the and _{4CaO · Al 2 O 3 · Fe} 2 O 3 and 2CaO · Fe ₂ O ₃ to the total low heat cement clinker manufacturing apparatus content to produce a low heat cement clinker from 7 to 20 percent of the.