JP2003313055A - Cement raw material and method of producing cement - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cement raw material in which the scrap wood of a silica heat insulating material largely produced in petrochemical plants, thermoelectric power plants or the like can effectively be utilized and recycled, and to provide a method of producing cement. <P>SOLUTION: The cement raw material is a pulverized material with a particle diameter of 50 mm obtained by pulverizing the scrap wood of a silica heat insulating material for the heat insulation of piping and/or tanks used in petrochemical plants, thermoelectric power plants or the like. The producing method is provided with a pulverized material producing stage where the above pulverized material is obtained; a preparation stage where the pulverized material, limestone and coal ash are prepared to obtain a preparation; a stage where the preparation is fired to obtain a clinker; and a finishing stage where gypsum is mixed into the clinker to obtain cement. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement raw material and a method for producing cement, and more specifically, it effectively recycles a large amount of waste silica heat insulating material generated in a thermal power plant or a petrochemical plant. The present invention relates to a cement raw material and a method for producing cement.

[0002]

2. Description of the Related Art Generally, in facilities such as thermal power plants and petrochemical plants, pipes, tanks and the like are provided with a heat retaining structure in order to improve heat retaining properties thereof. This heat retaining structure is
For example, a silica heat insulating material containing calcium silicate as a main component is held by a cover member made of an iron plate corresponding to the outer shape of a pipe, a tank, or the like. The silica heat insulating material having such a heat insulating structure is replaced with a new one by periodical inspection or the like. The waste material of the silica heat insulating material generated after the replacement cannot be recycled as a new heat insulating material, and is therefore disposed of as landfill as industrial waste.

[0003]

It is extremely difficult to secure a stable landfill disposal site due to factors such as the location environment in the landfill disposal of the waste material of the silica heat insulating material as described above. Therefore, in thermal power plants and petrochemical plants,
It is desired to effectively utilize a large amount of waste silica heat insulating material as a recycling resource without landfilling it as industrial waste.

[0004]

[Means for Solving the Problems] The present inventors have been able to supplement the waste material of the silica heat insulating material with natural clay which is the main raw material of cement and silicon dioxide (SiO ₂ ) which is the main component of natural silica stone,
The inventors have found that the waste material of the silica heat insulating material can be effectively used as a substitute for natural clay or natural silica stone as a raw material for cement, and have completed the present invention. Further, in a thermal power plant, a petrochemical factory, and the like, a large amount of coal ash is discharged in the same manner as the waste silica heat insulating material. Main component of the coal ash _(Al 2 _{O 3:} about 30%, SiO _2: about 50%) and, the main component of natural clay as a cement raw material _(Al 2 _{O 3:} about 15%, SiO _2: 65% ), The coal ash contains more Al ₂ O ₃ than the natural clay and SiO ₂
Is very scarce. Therefore, the present inventors can supplement the silica component of the coal ash with the silica heat insulating material waste material to bring the coal ash closer to the main component of the natural clay. The inventors have found that they can be effectively used as a substitute for, and have completed the present invention.

The cement raw material of the present invention is characterized in that the waste material of the silica heat insulating material is crushed to have a particle size of 10 to 100 mm. Further, the silica heat insulating material can be used for heat insulation of pipes and / or tanks used in petrochemical plants and the like.

The method for producing cement according to the present invention comprises a pulverized product producing step of pulverizing a waste silica insulation material to obtain a pulverized product,
A mixing step of blending at least the crushed product and limestone to obtain a blend; a firing step of firing the blend to obtain a clinker; and a finishing step of blending gypsum into the clinker to obtain cement. Is characterized by. In addition, the pulverized product may have a particle size of 10 to 100 mm. Further, the silica heat insulating material can be used for heat insulation of pipes and / or tanks used in petrochemical plants and the like. Further, the formulation can be prepared by blending coal ash in addition to the pulverized product and limestone. Further, the coal ash can be recovered from a thermal power plant or the like. Further, the waste material of the silica heat insulating material may contain calcium oxide and silicon dioxide, and the total amount of the calcium oxide and the silicon dioxide may be 70% or more based on the whole. Further, in the pulverized product producing step, fine powder generated when pulverizing the waste silica heat insulating material can be removed.

The "waste material of the silica heat insulating material" may be of any shape, size, composition and the like. Its shape is
For example, a rod shape, a curved rod shape, a flat plate shape, a curved plate shape, an irregular shape, etc. can be mentioned. The components can be, for example, 40 to 60% by weight of calcium oxide (CaO) and 60 to 40% by weight of silicon dioxide (SiO ₂ ) when the total of calcium oxide and silicon dioxide is 100% by weight. The silica heat insulating material can be, for example, a xonotlite-based calcium silicate heat insulating material.
Accordingly, the heat insulating material can be excellent in heat insulation and humidity control. Further, the above-mentioned "crushed product" is not particularly limited in its shape, size, main component and the like. The size is preferably, for example, a particle size of 10 to 100 mm. This is because if the particle size is less than 10 mm, the storage and transportation of this pulverized product becomes complicated, and if the particle size exceeds 100 mm, there are restrictions on the receiving mechanism side into which this pulverized product is charged. The particle size of the pulverized product is preferably 30 to 80.
mm, and more preferably 40 to 60 mm. Further, the above-mentioned “formulation” can be prepared by mixing various other raw materials in addition to the crushed product and limestone. Examples of the other various raw materials include natural clay, natural silica stone, iron raw materials, and the like, or a combination of two or more thereof. Moreover, as a substitute for the above-mentioned natural clay, for example, one or a combination of casting sand, coal ash, incinerated ash such as municipal waste, and sludge such as sewage can be mentioned. Examples of the iron raw material include polishing powder and dust ash.

Examples of the "cement" include Portland cement, mixed cement, special cement and the like. Examples of the type of Portland cement include normal, early strength, super early strength, moderate heat, sulfate resistant Portland cement and the like. Examples of the mixed cement include blast furnace, silica, fly ash cement and the like. Examples of the special cement include white, ultra-rapid hardening, colloid, oil well, geothermal well, expansion, and alumina cement. Furthermore, the above "fine powder"
Can be appropriately dust-treated to be sludge. Thereby, the sludge can be effectively used as a cement raw material. For reference, a powder obtained by crushing a silica refractory material used for the inner and outer walls of a building or the like can be used as a cement raw material.

[0009]

EFFECTS OF THE INVENTION According to the cement raw material of the present invention, the waste material of the silica heat insulating material which is generated in a large amount in a petrochemical factory or the like can be effectively utilized as a substitute for natural clay or natural silica as a raw material for cement and recycled. it can. As a result, the collection of natural clay or natural silica stone can be suppressed to a necessary minimum, and the cement production cost can be significantly reduced. Further, since the cement raw material has a particle size of 10 to 100 mm, it is easy to store and convey the cement raw material, and the cement raw material is not restricted by the receiving mechanism of the cement manufacturing facility and is easy to handle. be able to. Further, when the silica heat insulating material is for heat insulation of pipes and / or tanks used in petrochemical factories and the like, a large amount of waste silica heat insulating material can be effectively utilized as a cement raw material.

According to the cement manufacturing method of the present invention, the waste material of the silica heat insulating material is crushed to obtain a crushed product, and then the crushed product and limestone are blended to obtain a compounded product.
This formulation will be fired to obtain a clinker and then gypsum will be compounded to this clinker to obtain cement. Therefore, a large amount of waste silica heat insulating material generated in a petrochemical factory or the like can be effectively utilized as a substitute for natural clay or natural silica stone as a raw material for cement and recycled. As a result, the collection of natural clay or natural silica stone can be suppressed to a necessary minimum, and the cement production cost can be significantly reduced. Also, the particle size of the crushed product is 1
In the case of 0 to 100 mm, the crushed material can be easily stored and transported, and there is no restriction on the receiving mechanism of the cement manufacturing facility. Further, when the silica heat insulating material is for heat insulation of pipes and / or tanks used in petrochemical factories and the like, a large amount of waste silica heat insulating material can be effectively utilized as a cement raw material. Further, when the formulation is prepared by blending coal ash in addition to the pulverized product and limestone, it is possible to bring the coal ash closer to the main component of natural clay by the action of the waste material of the silica heat insulating material. Coal ash, along with waste silica insulation materials that are produced in large quantities in factories
It can be effectively used as a substitute for natural clay as a raw material for cement and recycled. Moreover, when the said coal ash is collect | recovered from a thermal power plant etc., the coal ash generated in large quantities in a thermal power plant etc. can be effectively utilized as a cement raw material. Further, when the waste material of the silica heat insulating material contains calcium oxide and silicon dioxide, and the total amount of the calcium oxide and the silicon dioxide is 70% or more with respect to the whole, the waste material of the silica heat insulating material is a silica component. Since it contains a large amount of, the waste material of the silica heat insulating material can be more effectively utilized as a cement raw material. Further, in the pulverized material producing step, when fine powder generated when pulverizing the waste material of the silica heat insulating material is removed, a pulverized material of higher quality can be obtained.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings. In this example, waste silica silica heat insulating material for heat insulation of pipes and tanks used in petrochemical plants, and coal ash generated at a thermal power plant are used as substitutes for natural clay and natural silicon as cement raw materials. It shall be. In addition, in the present embodiment, it is assumed that the pulverized product generation process is performed in the waste material treatment plant, and the mixing process, the firing process, and the finishing process are performed in the cement plant.

(1) Pulverized Material Generation Process As shown in FIG. 1, in the waste material processing factory 1, the waste material of the silica heat insulating material recovered from the petrochemical factory is appropriately stored in the storage facility 2. The waste material of this silica heat insulation material is 150 mm ×
It has a rectangular bar shape of 914 mm × 100 mm. In addition, a sample of the waste material of the silica heat insulating material was pressure-molded into a pellet shape and measured by a fluorescent X-ray apparatus.
O: 41.2%, SiO ₂ : 36.1%, Al ₂ O ₃ :
The content was 0.9%, MgO: 0.4%, TiO ₂ : 0.3% and the like. Here, the waste material of the silica heat insulating material contains calcium oxide (CaO) and silicon dioxide (SiO ₂ ),
It is preferable that the total amount of calcium oxide and silicon dioxide is 75% or more based on the whole. As a result, the waste material of the silica heat insulating material containing a large amount of silica component can be effectively used as a cement raw material.

The waste material W of the silica heat insulating material stored in the storage facility 2 is conveyed to the crusher 4 (manufactured by Horai Co., Ltd., model: XKST40100) via the belt conveyor 3. The crusher 4 has a crushing capacity of 10 t / day (8 hours operation). Then, the waste material W of the silica heat insulating material is crushed by the crusher 4 to have a particle size of about 50 mm, and a crushed silica heat insulating material waste material S (hereinafter, also simply referred to as crushed material S) as a cement raw material is obtained. Thereafter, the crushed material S is appropriately conveyed to the carry-out facility 6 via the belt conveyor 5, and is stored in a container (capacity: about 14 m ³ ) temporarily placed in the carry-out facility 6. And
The container loaded with the crushed material S is carried out toward the cement factory by a hook roll car or the like. The crusher 4 and the belt conveyor 5 are provided with one end side of a dust collecting duct 8 connected to the dust collector 7, and the dust collector 7 removes dust (fine powder) generated in the crusher 4 and the belt conveyor 5. Be recovered. Then, the collected dust is appropriately treated in the treatment facility 9 to generate sludge. This sludge can also be effectively used as a raw material for cement.

(2) Mixing Process Next, in the cement factory 10 shown in FIG.
In addition, coal ash recovered from a thermal power plant is mixed in an appropriate ratio to produce a high-quality clayey raw material (hereinafter also simply referred to as clay) that substitutes for natural clay and natural silica as a cement raw material. . This clay is stored in each raw material storage 11a, 11b, 11c in the same manner as other cement raw materials {limestone, iron raw materials (polishing powder, dust ash, etc.)}. These raw materials are put into the production line 12 via a receiving hopper (not shown).
Here, the production line 12 has a cement production capacity of 3000 t / day (8 hours operation). Further, in this production line 12, for the production of 1 ton of cement, limestone: 1200 kg, clay: 250 kg, iron raw material: 50
kg is required. The limestone and clay put into the production line 12 are roughly crushed by the coarse crusher 15 via the respective automatic weighing machines 13a and 13b to form a mixture. Then, the mixture is dried by the dryer 16 and then the raw material crusher 1
7, further finely pulverized, mixed with the iron raw material to be fed into the production line 12 via the automatic weighing machine 13c, and temporarily stored in the raw material silo 18.

(3) Firing Step Next, the mixture of the raw material silo 18 is preheated by the preheating machine 21 and then fired by the rotary kiln 22 at a predetermined firing temperature (1350-1450 ° C.) to form a molten clinker. Become. Then, the clinker is cooled by the cooler 23 and then stored in the clinker silo 24.

(4) Finishing Step Next, the clinker of the clinker silo 24 is mixed with the gypsum stored in the raw material storage 11d and then finely pulverized by the finishing pulverizer 25 to obtain cement. After that, this cement is cooled by a cooler 26 and then stored in a cement silo 27, and then, via a bulk storage tank 28 or a bagging machine 29, appropriate conveying means 30a, 30b, 3
It will be shipped to the outside with 0c. The chemical composition of the cement product produced in this way is CaO: 64.
_{2%, SiO 2: 22.2%} , Al 2 O 3: 5.2%,
Fe ₂ O ₃ : 3.1%, MgO: 1.4%, Na ₂ O:
0.6%, K ₂ O: 0.2%, H ₂ O: 0.6%, CO
₂ : It was 0.1%.

(5) Effects of the Embodiments As described above, in the cement manufacturing method of this embodiment, waste materials of silica heat insulating materials and coal ash, which are generated in large quantities in petrochemical plants, are used as natural clay and natural materials as cement raw materials. It can be effectively used as a substitute for silica stone and recycled.
As a result, the cement factory does not need to collect natural clay or natural silica stone, and the manufacturing cost of cement can be extremely suppressed. Further, in the present embodiment, since the pulverized product obtained by pulverizing the waste material of the silica heat insulating material to have a particle size of about 50 mm is used as the cement raw material, the storage and transportation of the cement raw material are easy, and It is possible to provide an easy-to-handle cement raw material without any restrictions on the receiving hopper of the production line in the cement factory.

It should be noted that the present invention is not limited to the above-mentioned embodiment, and various modifications may be made within the scope of the present invention according to the purpose and application. That is, in the present example, as a substitute for natural clay and natural silica as a raw material for cement, a waste material of silica heat insulating material and a mixture of coal ash were used in an appropriate ratio, but the present invention is not limited to this. It is possible to use only the silica heat insulating material waste material as a cement raw material, or to use a mixture of the silica heat insulating material waste material and combustion ash such as municipal waste in an appropriate ratio as a cement raw material. Further, in the present embodiment, the pulverized material producing step is carried out in the waste material processing factory 1, and the mixing step is carried out in the cement factory 10.
Although the firing process and the finishing process are performed, the present invention is not limited to this. For example, the crushed product producing process may be performed in the cement factory 10.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for explaining a pulverized product producing step.

FIG. 2 is an explanatory diagram for explaining a cement manufacturing process.

[Explanation of symbols]

1; Waste material treatment factory, 10: Cement factory, W: Waste material of silica heat insulating material, S: Ground material.

Claims (9)

[Claims] 1. A waste material of a silica heat insulating material is pulverized to have a particle size of 1
Cement raw material characterized by being 0 to 100 mm. 2. The cement raw material according to claim 1, wherein the silica heat insulating material is for heat insulation of a pipe and / or a tank used in a petrochemical factory or the like. 3. A pulverized product producing step of pulverizing a waste material of a silica heat insulating material to obtain a pulverized product, a preparing step of preparing at least the pulverized product and limestone to obtain a preparation, and a clinker by firing the preparation. And a finishing step of mixing the clinker with gypsum to obtain cement. 4. The crushed product has a particle size of 10 to 100.
The method for producing the cement according to claim 3, wherein the cement is mm. 5. The method for producing cement according to claim 4, wherein the silica heat insulating material is used for heat insulation of pipes and / or tanks used in petrochemical plants and the like. 6. The method for producing cement according to claim 3, wherein the mixture is prepared by mixing coal ash in addition to the pulverized product and limestone. 7. The method for producing cement according to claim 6, wherein the coal ash is recovered from a thermal power plant or the like. 8. The waste material of the silica heat insulating material contains calcium oxide and silicon dioxide, and the total amount of the calcium oxide and the silicon dioxide is 70% or more based on the whole amount. The method for producing the cement according to the item. 9. The method for producing cement according to claim 3, wherein in the pulverized product producing step, fine powder generated when pulverizing the waste material of the silica heat insulating material is removed.