JP6004880B2 - Method for producing Portland cement clinker - Google Patents

Description

  The present invention relates to a method for producing a Portland cement clinker. In detail, it is related with the cement compounding raw material and its manufacturing method regarding manufacture of the said Portland cement clinker.

  The cement industry is a mass-production / mass-consumption industry, and resource conservation and energy conservation are and will continue to be the most important issues. Mainly, the energy cost associated with firing and powdering of raw materials is large.

  For example, in order to produce Portland cement, which is produced in the largest amount, it is necessary to sinter the raw material prepared in a predetermined chemical composition at a temperature as high as 1450 ° C. to 1550 ° C. to obtain a clinker. The energy cost to obtain is enormous.

  Furthermore, in order to use the clinker lump produced by firing as cement, it is required to pulverize the clinker lump. Even at this time, much energy is consumed.

  Further, in connection with recent global environmental problems, effective use of waste, by-products, etc. has become an important issue. It is necessary to pulverize the raw material containing these wastes, by-products and the like to a certain level or more, and the power required for pulverization is enormous.

  In the cement industry, which is a mass production and mass consumption type industry, it is important to efficiently use or treat waste as raw materials and fuels during cement production, and to efficiently produce cement with resource and energy savings.

JP 2006-151748 A

  Of course, even if it can be produced with resource and energy savings, it does not make sense if the cement has certain physical properties. One of the factors affecting the physical properties of cement is free calcium oxide (free lime, f-CaO). Cement (clinker) with a large amount of free lime is preferable because it has a problem of agglomeration abnormality. One way to reduce this free lime is to sinter sufficiently at a high temperature or for a long time, but this conflicts with the solution to the problem of energy saving.

  Accordingly, an object of the present invention is to provide a method for producing a Portland cement clinker capable of reducing the total energy cost without sacrificing physical properties such as strength development and fluidity.

  In order to solve the above problems, the present inventors have conducted intensive studies. As a result, in the pulverization of the mixed raw material, by making the raw material finer, it becomes easier to be fired, not only can the energy during firing be reduced, but also surprisingly the clinker lump obtained is easily crushed. The present inventors have found that grinding energy can be reduced and have accumulated further knowledge to complete the present invention.

That is, the present invention is a method for producing a Portland cement clinker including a step of pulverizing a mixed raw material and firing the powdered raw material to obtain a clinker.
Portland the powder of the raw material, 212 m Furuizan is 2 mass% or less, 90 [mu] m Furuizan 20 mass% or more, 26 wt% or less, and performs as 38μm Furuizan is 9 5 mass% or more This is a method for producing a clinker.

  According to the present invention, the calcination can be reduced when firing the clinker, so that the firing energy can be reduced, and the clinker having a good grinding efficiency when the cement is made from the fired clinker can be obtained, so that the grinding energy can be reduced. In addition, it is possible to obtain a cement having good physical properties such as strength development and the like.

In the production method of the present invention, a powder of the mixed materials, 212 m Furuizan is 2 mass% or less, 90 [mu] m Furuizan 20 mass% or more, 26 wt% or less, so that 38μm Furuizan is 9 5 mass% or more To do. If the 212 μm sieve residue exceeds 2% by mass, or the 90 μm sieve residue exceeds 26% by mass, the energy required for sufficient firing increases (high temperature is required) or (low temperature Cement strength developability is reduced). Furthermore, the energy required for pulverization of the obtained clinker cannot be reduced.

  On the other hand, since the effect of pulverization reaches a certain level, when it is made too fine, the disadvantage that more pulverization energy is required in powdering of the raw material exceeds other merits. The balance is 90% by mass or more.

The 212 μm sieve residue is preferably 1.5% by mass or less. 90μm Furuizan is good Mashiku is 22.5 to 25 wt%. It is Raniwa, and more preferably 75μm Furuizan is 25 to 35 mass%.

  The method for producing the cement clinker of the present invention is not particularly limited, and a known cement raw material is prepared and mixed at a predetermined ratio so as to have a mineral ratio and coefficient of a known cement clinker, and a known method (for example, It can be easily obtained by mixing and pulverizing the raw materials so as to have a predetermined fineness with a ball mill, a vertical mill, etc., and firing by a known method (for example, SP kiln or NSP kiln).

As concrete cement raw materials,
Examples include CaO sources such as limestone, quicklime and slaked lime, SiO ₂ sources such as silica, Al ₂ O ₃ sources such as clay, Fe ₂ O ₃ sources such as iron sources, etc. Furthermore, waste, by-products, etc. are used Of course, it is possible.

In the production method of the present invention, it is preferable to use one or more of wastes, by-products and the like from the viewpoint of promoting effective use of wastes, by-products and the like. Specific examples of usable waste and by-products include blast furnace slag, steelmaking slag, non-ferrous iron slag, coal ash, sewage sludge, purified water sludge, papermaking sludge, construction generated soil, foundry sand, dust, incineration fly ash, melting Examples include fly ash, chlorine bypass dust, wood scrap, waste white clay, waste, tires, shells, municipal waste and incinerated ash. is there)
As a raw material preparation method, the chemical composition of each raw material is measured, the preparation ratio of each raw material is calculated so as to be within a desired range from the ratio of each component in the raw material, and the raw material is prepared at that ratio. .

The blending ratio of the raw materials is not particularly limited as long as it generates Portland cement clinker, and can be applied to any Portland cement such as ordinary Portland cement, moderately hot Portland cement, low heat Portland cement, early-strength Portland cement, etc. Has a C ₃ S content of 40 to 75% by mass, a C ₂ S content of 5 to 25% by mass, a C ₃ A content of ₃ to 15% by mass and a C ₄ AF content of 7 to 25% by mass. More preferably, the C ₃ S content is 50 to 70% by mass, the C ₂ S content is 10 to 20% by mass, the C ₃ A content is 7 to 12% by mass, and the C ₄ AF content is 7%. ˜12% by mass.

  In the production method of the present invention, the respective raw materials may be individually pulverized and mixed, or may be pulverized after mixing. The pulverization method can use the same ball mill, vertical mill and the like as in the production of a known Portland cement clinker, and is not particularly limited, but a ball mill is preferred. In pulverization, classification is usually performed to obtain a mixed raw material having a desired particle size. For the classification, a known method can be appropriately employed. For example, the classification is performed using a dry classifier such as an air separator, and the residue of the 212 μm sieve residue is 2% by mass or less, the 90 μm sieve residue is 26% by mass or less, and the 38 μm sieve residue is 90%. Classification is preferably performed so that the 90 μm sieve residue is 20 to 26% by mass, and the 38 μm sieve residue is 95% by mass or more so as to be at least mass%.

  The firing method is not particularly limited, and an apparatus capable of high-temperature heating such as an NSP kiln known as an existing Portland cement manufacturing facility or a cement kiln represented by an SP kiln can be preferably used. The firing temperature is usually about 1400 to 1500 ° C.

The Portland cement clinker produced by the method of the present invention can be used in the same manner as known Portland cement clinker. That is, it may be mixed with gypsum or the like so that the amount of SO ₃ is 1.5 to 5.0% by mass, and pulverized until the specific surface area of branes becomes about 2800 to 4500 cm ² / g.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to these Examples.

  Using industrial raw materials containing wastes such as limestone, coal ash and construction generated soil, the raw materials were formulated so that clinker of different composition including general-purpose cement clinker composition was obtained on a fired basis. Table 1 shows the mineral composition and coefficient values of the prepared raw materials according to the Borg formula.

  The raw material was pulverized by changing the time with a ball mill to prepare three samples (A to C). 100 g of each raw material powder sample was weighed and classified by overlapping sieves of 212 μm, 90 μm, 75 μm, and 38 μm. Table 2 shows the classification results and the sieve residue of each sieve of each sample. In addition, this sieve residue is displayed including the classification result with a large sieve mesh. That is, the 90 μm sieve residue is a combination of the classification amount of the 212 μm sieve and the classification amount of the 90 μm sieve, and the 38 μm sieve residue is the combination of the classification amounts of the 212 μm sieve, the 90 μm sieve, the 75 μm sieve, and the 38 μm sieve. Is.

Each sample was fired at a predetermined temperature for 90 minutes to obtain a cement clinker. Gypsum was added to the cement clinker so that the SO ₃ content was 1.8 to 1.9% by mass, and the mixture was pulverized to have a brain specific surface area of 3200 to 3300 cm ² / g to prepare a cement. At that time, the grinding time required until the Blaine specific surface area reached 3100 cm ² / g was measured and used as an index of grindability. The mortar compressive strength and cement paste flow of the obtained cement were measured. Table 3 shows the firing temperature, free lime, pulverization time, mortar compressive strength, and paste flow results for each example.

Moreover, each measurement is based on the following method.
(1) Measurement of chemical composition of raw material and cement clinker: Measured by a fluorescent X-ray analysis method according to JIS R 5204.
(2) Measurement of mortar compressive strength: It was measured by a method based on JIS R 5201.
(3) Measurement of cement paste flow: Measured according to JASS 15 M-103, mixing time is 3 minutes, water / cement ratio is 0.50, no admixture added test temperature is 20 ° C. The flow immediately after was measured.

  Examples 1 to 3 relate to the present invention, and f-CaO shows 1.0% or less in 1450 ° C. firing, so that easy firing is good and the pulverization time until a predetermined brane value is reached. Can be done in a short time. Moreover, the strength development property is also a favorable result in each material age.

  Comparative Examples 1 and 2 show the results when the raw material particle size is coarser than the Examples, and f-CaO shows a very high value of 1.61% when calcined at 1450 ° C. I understand. It can also be seen that the pulverization time required to reach a predetermined brain value is longer than that of the example. It can be seen that the strength development is also significantly reduced compared to the examples.

Claims (4)

In the manufacturing method of Portland cement clinker including the step of pulverizing the mixed raw material and firing the powdered raw material to obtain the clinker,
Portland the powder of the raw material, 212 m Furuizan is 2 mass% or less, 90 [mu] m Furuizan 20 mass% or more, 26 wt% or less, and performs as 38μm Furuizan is 9 5 mass% or more A manufacturing method of toncliner. The method according to Portland cement clinker of claim 1, wherein performing a powder of the raw material as 75μm Furuizan is 25 to 35 mass%.   The method for producing a Portland cement clinker according to claim 1 or 2, wherein the raw material is powdered with a ball mill. A raw material powder used in a method for producing a Portland cement clinker including a step of firing a powdery raw material to obtain a clinker,
212μm Furuizan is 2 mass% or less, 90 [mu] m Furuizan 20 mass% or more, 26 wt% or less, Portland cement clinker production raw material powder wherein a 38μm Furuizan is 9 5 mass% or more.