Calcium ferroaluminate compound, cement admixture and process for producing same, and cement composition

A technology of calcium ferric aluminate and compound, applied in iron compounds, chemical instruments and methods, inorganic chemistry, etc., can solve the problem of not confirming the effect of nitrite acid resistance, etc., and achieve excellent anti-rust effect, infiltration inhibition, The effect of sufficient operating time

Active Publication Date: 2014-04-02
DENKA CO LTD
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the effect of nitrite imparting acid resistance was not confirmed

Method used

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  • Calcium ferroaluminate compound, cement admixture and process for producing same, and cement composition
  • Calcium ferroaluminate compound, cement admixture and process for producing same, and cement composition
  • Calcium ferroaluminate compound, cement admixture and process for producing same, and cement composition

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0063] (specification of the crystal structure of the compound)

[0064] Synthetic calcium ferrite (C 2 F), calcium aluminum ferrite (C 4 AF, C 6 A 2 F, C 6 AF 2 ), calcium aluminate, calcium aluminate (CA 2 ).

[0065] figure 1 Show calcium ferrite (C 2 F) and calcium aluminum ferrite (C 4 AF, C 6 A 2 F, C 6 AF 2 ) XRD measurement result. Depend on figure 1 It can be seen that these have the same crystal structure.

[0066] on the other hand, figure 2 Calcium aluminate and calcium aluminate (CA 2 ) XRD measurement result. It can be seen that calcium aluminum ferrite maintains CA 2 While the structure, Fe 2 o 3 solid solution. In addition, if Fe 2 o 3 If it exceeds 15%, there will be no solid solution, and the precipitation of magnetite can be seen. It has been confirmed from the above that calcium aluminate ferrite is different from the previously known CaO-Al 2 o3 -Fe 2 o 3 The calcium aluminum ferrite system compound is a completely different co...

experiment example 1

[0068] Calcium carbonate of reagent grade 1 and aluminum oxide of reagent grade 1 were compounded so that the molar ratios shown in Table 1 were obtained in terms of oxides, and iron oxide of reagent grade 1 was adjusted to the ratio shown in Table 1 with respect to the complex. Fe 2 o 3 The method of content is compounded and fired in an electric furnace. CaO / Al 2 o 3 The substance with a molar ratio of 0.7 is at 1400°C, CaO / Al 2 o 3 The substance with a molar ratio of 0.6 is at 1450°C, CaO / Al 2 o 3 The substance with a molar ratio of 0.4 is at 1500°C, CaO / Al 2 o 3 The substances with a molar ratio of 0.15 were respectively calcined at 1550° C. for 3 hours, and then slowly cooled to synthesize them. All Blaine values ​​adjusted to 4,000cm 2 / g. In addition, for comparison, for the case of not adding iron oxide, containing SiO 2 case, containing R 2 The case of O is also synthesized in the same manner. The presence or absence of unreacted substances was evaluated...

experiment example 2

[0078] Cement compositions were prepared by mixing 7 parts of the CFA compounds shown in Table 2 with 100 parts of cement compositions consisting of cement and CFA compounds, and mortars with a water / binder ratio of 0.5 were prepared in accordance with JIS R 5201. Using this mortar, setting time, antirust effect, compressive strength, chloride penetration depth, Ca ion infiltration, and sulfate resistance were investigated. The results are also listed in Table 1. In addition, the test was performed at an ambient temperature of 30°C.

[0079]

[0080] CFA compound A: mix the calcium carbonate of the reagent grade 1 with the alumina of the reagent grade 1 in a specified ratio, and use Fe 2 o 3 The iron oxide of grade 1 of the reagent is mixed so that the content becomes 3%, and it is synthesized by firing in an electric furnace at 1550°C in the same manner as in Experimental Example 1, and then slowly cooling CaO / Al 2 o 3 Molar ratio 0.1, Blaine value 4,000cm 2 / g

[008...

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Abstract

It is the object of the invention to provide a cement admixture, and a cement composition that can impart good enough rustproofness to reinforcing bars in hardened cement concrete, and can have resistance to penetration of chloride ions entering from the outside, present the hardened cement concrete from getting porous due to reduced leaching of Ca ions and have a self-recovery capability. The invention provides a cement admixture characterized by containing a calcium ferroaluminate compound comprising a CaO-Al 2 O 3 -Fe 2 O 3 system, and having a Fe 2 O 3 content of 0.5 to 15% by mass and a CaO·2Al 2 O 3 structure with a CaO / Al 2 O 3 molar ratio ranging from 0.15 to 0.7. It is preferable that the fineness is 2,000 to 7,000 cm 2 / g as represented in terms of the Blaine's specific surface area value; the potentially hydraulic substance and / or pozzolan substance (pozzolan substance or the like) is also used; the pozzolan substance or the like contains one or two or more selected from the group consisting of finely pulverized, quenched, granulated blast-furnace slag, fly ash, silica fume, metakaolin, incinerated pulp sludge ash, incinerated sewage sludge ash, and waste glass powder; and the blending proportion of the calcium ferroaluminate compound to the pozzolan substance or the like ranges from 10 / 1 to 1 / 10 by mass. The invention also provides a cement composition containing cement and the cement admixture.

Description

technical field [0001] The present invention mainly relates to cement admixtures and cement compositions used in civil engineering and construction industries. Background technique [0002] CaO-Al used as cement admixture 2 o 3 -Fe 2 o 3 The compound of the system is known as calcium aluminum ferrite. Calcium aluminum ferrite known as 4CaO·Al 2 o 3 · Fe 2 o 3 (C 4 AF), 6CaO 2Al 2 o 3 · Fe 2 o 3 (C 6 A 2 F), 6CaO·Al 2 o 3 2Fe 2 o 3 (C 6 AF 2 )Wait. [0003] These aluminum calcium ferrites have 2CaO·Fe as one of the calcium ferrites 2 o 3 (C 2 F) Crystal structure. Namely, Al 2 o 3 Much solid solution in C 2 While F, the crystal structure remains C 2 The structure of F, to obtain Al with various compositions 2 o 3 / Fe 2 o 3 The molar ratio of. C 2 The crystal structure of F is orthorhombic, [0004] On the other hand, CaO·2Al is known as one type of calcium aluminate 2 o 3 (CA 2 ). CA 2 The crystal structure is monoclinic, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B22/08C01G49/00
CPCC01G49/0045C04B28/02C04B7/32C01P2002/72C01G49/0036C04B22/0093C04B2111/26Y02W30/91C04B2103/0088C04B14/106C04B14/22C04B18/08C04B18/10C04B18/141C04B18/146
Inventor 森泰一郎田原和人山本贤司盛冈实樋口隆行
Owner DENKA CO LTD
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