KR100404337B1 - The method for manufacturing of active portland cement - Google Patents

Abstract

The present invention is 80 to 90 parts by weight of low-grade limestone with a K ₂ O content of 1 part by weight or more, 2 to 5 parts by weight of clay or feldspar, etc. of clay material, 1 to 3 parts by weight of sulfate raw materials such as jarosite (pet cokeyl 10-15 parts by weight of the fuel), 1 to 3 parts by weight of red mud mixed with fluorapatite 0.2 to 0.7 parts by weight based on the F- so that the powder of the raw material is 88μm residues or less 15 parts by weight After controlling and firing at 1450 ℃ in a rotary furnace, and relates to a method of producing a high-active cement, characterized in that the powder is prepared by grinding to 3000 to 4000cm ² / g without any additional gypsum.

Description

{The method for manufacturing of active portland cement}

The present invention relates to a method for producing a high active cement, and in detail, to increase the initial and long-term hydration activity of the common portland cement that is commonly used as a general building material, relatively high strength without using the existing high-strength mixtures or additives The present invention relates to a method for producing highly active cement having the effect of shortening air and giving durability, which is the most important factor in civil construction work.

The present invention relates to a manufacturing method for changing a homogeneous low-temperature structure of allite (C ₃ S), which has the greatest influence on the strength characteristics of the constituent compounds of cement clinker, to a crystal structure having high hydration activity. It is about a technique for dramatically improving long-term strength. Currently, the first type of Portland cement used as the main material in the field of construction civil engineering does not satisfy the requirements for the construction method and application development of the construction and civil engineering, which are diversified, despite its versatility.

At present, this problem is addressed by the development of construction methods, but it is time to develop materials to solve more fundamental problems. Moreover, considering that the reduction of construction period and the development of high strength are the most important considerations in the selection of cement materials. There is a need for the development of cement that meets these needs.

Generally, Portland cement is composed of clinker compounds such as allite (C ₃ S), bellite (C ₂ S), and interstitial (C ₃ A, C ₄ AF). Each has its own characteristics. Allite is a mineral that plays the most important role in the expression of physical properties of cement. During its cooling stage, allite undergoes various phase transformation processes depending on the amount, type and cooling conditions of the trace components employed in the crystal structure. It is a major condition for property expression. The crystal structure of the commonly used ordinary portland cement is a triclinic form that is poorly hydrated. The phase transformation process is as follows.

600 ^o C 920 ^o C 980 ^o C 990 ^o C 1060 ^o C 1070 ^o C

T1 → T2 → T3 → M1 → M2 → M3 → R

(T: triclinic, M: monoclinic, R: rhombohedral)

In order to increase the hydration activity of the alite, it is necessary to exist in the R type rather than the T and M types. The method for this is to control the cooling rate and stabilize the solution by solid solution in the alite lattice. In reality, the control of the cooling rate is difficult to realize due to the limitation of the equipment, and the method by the trace component is possible.

The existing method for giving the initial activity of cement is a method for producing cemented carbide. In Japan, the cement known as jet cement is the main mineral phase changed to C ₁₁ A ₇ CaF ₂ by the addition of fluorite (CaF ₂ ), and the hydration of this mineral is carried out within a day and shows very fast fastness. As another method, there is a method for producing an Arwin-based cement which is mainly made of various sulfates and bauxite. The main mineral phase of this cement is C ₄ A ₃ S, which also has a fast hardening which gives a practical strength in one day.

In addition, Korean Patent Publication No. 10-220340 discloses 40-50 parts by weight of limestone as CaO source, aluminum sludge as Al ₂ O ₃ source, shale and dihydrate gypsum mixture as SiO source and then 1200 ~ 1350 ℃. The mixture was calcined for 1 hour at to prepare a clinker composed mainly of calcium aluminate (12CaO · 7Al ₂ O ₃ ) _, calcium silicate, calcium sulfoaluminate, and then 60 to 80 parts by weight of the grinder pulverized product, and anhydrous gypsum 10 to 30. A technique is described for a fast-hardening cement composition in which 99 to 99.9 parts by weight of a mixture consisting of 1 part by weight and 1 to 13 parts by weight of plaster and 0.1 to 1 part by weight of gypsum is mixed.

Korean Laid-Open Patent Publication No. 10-98-82507 uses fluorinated salts composed of magnesium fluoride, zinc fluoride, sodium fluoride, manganese fluoride and calcium fluoride, and type II anhydrous gypsum and is an industrial by-product as a subsidiary material. Techniques for powder admixtures for high strength concrete are disclosed using coal ash and / or blast furnace slag fine powder.

In the conventional method of manufacturing fast cement, the main mineral is completely different from the ordinary portland cement, and the firing process itself is also different. This entails process problems. In addition, the main application is a rigid repairing material, and its range of use is very different from that of ordinary Portland cement. In addition, the jet cement has a weak resistance to sulfate, Irwin-based cement is very poor resistance to heat. Table 1 shows the difference between the technology of the present invention and the existing fast cement.

Table 1. Comparison of fast cement

Remarks Hydration mineral Main raw material Attainment of practical strength Firing temperature ( ^o C) Usage Invention C ₃ S Ordinary cement raw material, apatite 3 days 1450 General, high strength concrete Jet Cement C ₁₁ A ₇ CaF ₂ Limestone, Fluorite 5-10 hours 1100-1200 For repair Awin Cement C ₄ A ₃ S Sulfate, limestone, bauxite One day 1250-1350 For repair

In order to solve the problems described above, the present invention solves the problems of the initial strength and the long-term strength, which are disadvantages of the characteristics of ordinary portland cement, and solves problems such as lengthening of the formwork type due to the initial strength decrease in mass-casting concrete structure construction. It is an object of the present invention to provide a method of producing high-active cement that fundamentally solves the problem of generating heat of hydration in sub-mixed concrete by exhibiting high strength even with low amount of cement.

The present invention is a low-grade limestone 80 to 90 parts by weight of K ₂ O content of more than 1 parts by weight of limestone, which is the main raw material in the firing of the ordinary Portland cement clinker, clay or feldspar 2 to 5 parts by weight of clay raw materials, 1 to 3 parts by weight of sulfate raw materials such as jarosite (10 to 15 parts by weight of fuel in the case of pet coke) and 1 to 3 parts by weight of red mud are mixed so as to have 0.2 to 0.7 parts by weight of fluoroapatite on an F ⁻ basis. . It relates to a high active cement and a method for manufacturing the composition of which the composition ratio of the combination is adjusted so that the weight ratio of the minor component to the F ^- ion in the composition is 0.1-0.5 / 1.0-1.5 ratio.

The role of these minerals is so important that the physical properties of portland cement are largely dependent on calcium silicate compounds (allite, bellite), which make up most of the constituent clinker compounds. Particularly, allite is a compound that has a great influence on the initial strength and long-term strength of ordinary cement, which is an important variable that affects the quality of overall concrete. As described above, the main crystal structure of allite maintains a triclinic type under conventional manufacturing facilities, and its characteristics are low initial strength and low hydration activity.

Initial hydration activity is greater rombo head barrels in order to produce the Al light of (rhombohedral) type is employed in the minor constituent to maintain the crystal structure at high temperature is very important and typical trace components therefor are fluorine (F ^-), Fluorite (CaF ₂ ) or pullor apatite (Ca ₅ (PO) ₄ F) may be a representative raw material in the natural state as ions such as zinc (Zn). The adjustment of the solubility of trace components is not simple, and proper solution of appropriate ions should be made in consideration of the solution molar ratio of each ion. If F ^- ions are solely dissolved in the alite, stabilization of the R-type alite is not expected, and thus there is no effect of increasing the hydration activity. That is, the effect of hydration activity can be obtained only when the solid solution with other ionic species, that is, the solid solution with ions such as Al, Mg, Zn, and SO ₃ .

In theory, F ^- ions are hardly dissolved in 0.5% or more of Allite alone, and the above ^-mentioned solid solution is transferred to other minerals with phase transitions such as C ₁₁ A ₇ CaF ₂ . Sudden deterioration occurs, causing various problems such as difficulty in controlling the plasticity process. Fluorine apatite, fluorite (CaF ₂ ), etc. may be used as a raw material for supplying F ⁻ , and in particular, in the case of fluoroapatite, it is very advantageous to control the calcination process.

Co-employment of F ^- ions with other trace components is also a technical problem to be achieved in the present invention. The continuous solid solution of alite to be finally obtained in the present invention may be represented by the following formula.

Ca ₃ Si _1-x M _x O _5-x F _x (M: Al) or Ca _3-x M _x SiO _5-x F _x (M: Mg, Zn, SO ₃ )

The role of these trace components is closely related to the viscosity control of the molten phase during the firing process, and each ion is dissolved together in the alite lattice to thermodynamically increase the stabilization range of the R type, thereby promoting the production of R type alite. Fundamentally increases hydration activity. Meanwhile, raw material ships for the supply of trace components are also very important factors. Al and Mg may be used as clay and limestone raw materials, but other raw materials and fuels should be considered for the supply of Zn and SO ₃ . It is preferable to use red mud as the raw material of Zn, and to use pet coke, jarosite and the like as the SO ₃ raw material. These raw materials are all kinds of wastes. Technical considerations should also be taken to solve the problems that may arise when these lead and raw materials are introduced into the process.

In the preparation of the cement of the present invention, the powder of the raw material is adjusted to have an amount of 88 μm or less in an amount of 15 parts by weight or less, thereby promoting solid phase reaction in a rotary furnace and firing at 1450 ^° C. The calcined clinker is prepared by pulverizing the powder to 3000 to 4000 cm ² / g without additional gypsum or by mixing 40 to 60 parts by weight of fly ash or slag, which is an industrial by-product, for the prepared high active cement. .

The roles and mechanisms for each step in the manufacturing process are as follows. Cl by having an effect that is substituted in place ^- if the role of the minor components in each composition fluorine apatite is at least about 800 ^o C F ^- ions begins to volatilize, and the volatilized F chlorine ions and the like are condensed in the vicinity of the preheater ^- to prevent the clogging of the material caused by the F ion and volatilization in the ^step-ion has the effect of which is substituted with oxygen (O ^2-) of the Al light structure as the calcination proceeds place in the kiln. This is represented by the following reaction scheme.

(F ^- ↑)

Ca ₅ (PO) ₄ F → Ca ₅ (PO) ₄ Cl + Ca ₃ SiO _5-x F _x

(Cl ^- ↓)

F ^- in addition to the principle that waste materials that interact with the firing process to be used for the supply of trace components are as follows. SO ₃ in jarosite and pet coke is volatilized during the firing process and participates in lattice employment inside C ₃ S together with F ^- ions to promote formation of highly active R-type allite. SO ₃ circulating inside the kiln in excess is red mud or the high alkali and alkali and reaction of the limestone eliminate the process instability, aligning the molar ratio of alkali / sulfur and the condensed compound, double salt (nitro calcium Trang Bay: 2CaSO ₄ · K ₂ SO ₄ ) adheres to the clinker surface during the cooling process. This double salt plays a role in eliminating the post-adding process of gypsum, which is essential in cement manufacturing. In the same principle, the use of red mud results in a solid solution effect of Zn in the alumina of the trace component to stabilize the R-type alite by F ^- ion, and the alkali present reacts with S to form a double salt. It adheres to the clinker surface.

If the content of F ^- ion is too low compared to other trace components, the effect of hydration activity due to the formation of R type allite is insignificant, and if the content of other trace components is high, abnormal hydration delay and abnormal development of clinker minerals may result. Will adversely affect.

When slag or fly ash is mixed, it is possible to prevent the degradation of initial strength, which is the most problematic when using these materials, which makes it ideal for large-scale civil engineering works such as waste treatment plants, port facilities, airports, and bridges.

The present invention will be described in more detail with reference to the following Examples.

Examples (1-4)

F ^- ion clinker 0.1 parts by weight and 0.5 parts by weight in the total alite and 2.3 to 2.6 parts by weight of dissolved gypsum in the total clinker was calcined in a rotary furnace at a temperature of 1450 ^o C powder powder 3200 cm ² / g Cement was prepared after grinding in a ball mill. Fineness is 3000 cm ² / g of fly ash and the powder also has 4000cm ² / g was produced in the blast furnace granulated slag, 40 parts by weight was added to a mixer mixing the cement with respect to the manufacture of cement. The compounding ratio of the Example is shown in Table 2.

Comparative Example (1 to 3)

Fineness is 3200cm ² / g is usually prepared using a Portland cement ball mill was the fineness of the manufactured cement 3000 cm ² / g of fly ash and the fineness is 4000cm ² / g, 40 parts by weight of a blast furnace granulated slag To add a mixed cement was prepared using a mixer. The compounding ratio of the comparative example is shown in Table 2.

TABLE 2

division F-content (%) High activity cement Common Portland Cement Fly ash Slag Example 1 0.12 100 parts by weight - - - Example 2 0.46 100 parts by weight - - - Example 3 0.46 60 parts by weight - 40 parts by weight - Example 4 0.46 60 parts by weight - - 40 parts by weight Comparative Example 1 - - 100 parts by weight - - Comparative Example 2 - - 60 parts by weight 40 parts by weight - Comparative Example 3 - - 60 parts by weight - 40 parts by weight

Experimental Example

In order to test the physical properties of the cements prepared in Examples and Comparative Examples, a condensation and compressive strength test method according to KS was used, and EPMA (Electron Probe Micro Analysis) was used to confirm the high capacity of F ^- ion in allite. . The results are shown in Tables 2 and 3.

TABLE 3

Remarks (Min.) Compressive strength (kg / cm ² ) Candle texture Termination 1 day 3 days 7 days 28 days 56 days Example 1 140 195 185 343 445 540 610 Example 2 245 320 260 475 526 649 712 Example 3 260 385 179 286 367 557 618 Example 4 265 400 165 279 377 589 648 Comparative Example 1 185 335 92 147 298 389 422 Comparative Example 2 290 395 46 112 201 346 417 Comparative Example 3 285 375 53 121 212 392 456

The present invention as described above has the advantage that the raw material is cheap and easy to produce. Highly active cements have the following advantages:

First, it can shorten the construction period by improving the initial strength of concrete due to the activation of allite and dramatically improve the durability of concrete structures. Second, it is economical and environmentally friendly because it utilizes low grade or waste such as high alkali limestone and pet coke. Third, it is possible to omit the gypsum addition process that is inevitably involved in the manufacture of cement, which can simplify the process, significantly reducing the manufacturing cost.

Claims (3)

In the manufacturing method of high-active cement, 80 to 90 parts by weight of low-grade limestone with K ₂ O content of 1 part by weight or more, 2 to 5 parts by weight of clay or feldspar in clay materials, 1 to 3 parts by weight of sulfate raw materials such as jarosite (10 to 15 parts by weight of fuel in the case of pet coke), 1 to 3 parts by weight of red mud mixed with fluoroapatite to 0.2 to 0.7 parts by weight based on the F-, the powder of the raw material of the 88μm residue 15 weight The method of manufacturing a highly active cement, characterized in that it is prepared to be pulverized in the rotary furnace at 1450 ^o C in a rotary furnace and then pulverized to 3000 to 4000 cm ² / g without additional gypsum. The method according to claim 1, wherein the composition is manufactured by adjusting the composition ratio of the combination so that the weight ratio of the trace component to F ⁻ ions in the manufactured fired product is 0.1-0.5 / 1.0-1.5. In the manufacturing method of high-active cement, 80 to 90 parts by weight of low-grade limestone with K ₂ O content of 1 part by weight or more, 2 to 5 parts by weight of clay or feldspar in clay materials, 1 to 3 parts by weight of sulfate raw materials such as jarosite (10 to 15 parts by weight of fuel in the case of pet coke), 1 to 3 parts by weight of red mud mixed with fluoroapatite to 0.2 to 0.7 parts by weight based on the F-, the powder of the raw material of the 88μm residue 15 weight It is adjusted to less than a part and fired at 1450 ^o C in a rotary furnace and then pulverized to 3000 to 4000 cm ² / g of powder without any gypsum added to the mixture to 2000-3000 cm ² / g, fly ash, Highly active mixed cement, characterized in that manufactured by mixing 30 to 70 parts by weight of blast furnace slag of 3000-5000cm ² / g.