AU2021242669B2

AU2021242669B2 - Cement clinker and cement composition

Info

Publication number: AU2021242669B2
Application number: AU2021242669A
Authority: AU
Inventors: Hideyuki Nasu; Tomoki Sato; Jun Shimizu; Yoh YAMADA; Kyosuke Yamagata
Original assignee: Sumitomo Osaka Cement Co Ltd
Current assignee: Sumitomo Osaka Cement Co Ltd
Priority date: 2020-03-27
Filing date: 2021-03-18
Publication date: 2022-07-21
Anticipated expiration: 2041-03-18
Also published as: AU2021242669A1; CN114080372A; JP6780798B1; CN114080372B; JP2021155291A; KR102338228B1; WO2021193368A1; SG11202113234YA; KR20210135604A; NZ782813A

Abstract

Provided is cement clinker and a cement composition with which it is possible to improve the strength development of mortar while suppressing the increase in environmental impact. A cement clinker wherein: the proportion of 3CaO·SiO

Description

DESCRIPTION TITLE OF INVENTION CEMENT CLINKER AND CEMENT COMPOSITION

Technical Field

[0001]

The present invention relates to a cement clinker and

a cement composition, especially ordinary Portland cement.

Background Art

[0002]

As a method for improving strength development of

mortar, a method for increasing fineness (Blaine's specific

surface area) of a cement composition and a method for

increasing a content of 3CaO-SiO2 in a cement composition

are known (Non Patent Literature No. 1).

In addition, TiO 2 and MgO, which are trace components

in a cement clinker, give to a mineral composition and a

physical property of cement. For example, it has been

reported that when a MgO content increases, reactivity of

alite decreases and strength development decreases (Non

Patent Literature No. 2).

Citation List

[00031

Non Patent Literature

[Non Patent Literature No. 1] Cement Association,

"Common Knowledge of Cement", "4. Types and Applications of

Cement", 2004, pp. 11-17

[Non Patent Literature No. 2] Keiji Chabayashi et

al., "Effects of TiO 2 and MgO on clinker mineral composition

and physical properties of cement", Cement and Concrete

Proceedings, vol. 66 (2012), pp. 211-216

[0003a]

Any discussion of the prior art throughout the

specification should in no way be considered as an admission

that such prior art is widely known or forms part of common

general knowledge in the field.

Summary of Invention

Technical Problem

[0004]

However, when the strength development of mortar is

increased by means for changing the fineness or mineral

composition of the cement composition, such as increasing

the fineness as in Non Patent Literature No. 1 and

increasing the content of 3CaO-SiO2, a problem that setting

time is shortened and fluidity is lowered arises.

In addition, in order to increase the fineness, a

problem that energy required for pulverizing a cement

clinker increases arises, and when a content of 3CaO-SiO2 is

to be increased, a problem that a limestone basic unit is

required to be increased arises.

All of these are not preferable because the problems

lead to an increase in carbon dioxide emissions and an

increase in energy for clinker calcining, which increases

an environmental burden.

[00051

Further, as in Non Patent Literature No. 2, it is not

possible to obtain a sufficient improvement in the strength

development of the mortar only by examining contents of TiO 2

and MgO.

Therefore, an object of the present invention is to

provide a cement clinker composition capable of improving

the strength development of mortar while suppressing an

increase in environmental burden by examining a content of

each compound in a cement clinker.

It is an object of the present invention to overcome

or ameliorate at least one of the disadvantages of the

prior art, or to provide a useful alternative.

Unless the context clearly requires otherwise,

throughout the description and the claims, the words

"comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of

"including, but not limited to".

Solution to Problem

[00061

In cement clinker manufacture and cement manufacture,

a physical property of cement is affected by not only main

components such as A1 2 0 3 but also various trace components,

manufacture conditions, or the like.

Non Patent Literature No. 2 reports on an influence of

TiO 2 and MgO on a clinker mineral composition and a physical

property of cement, but simply adjusting the content of

these components is not sufficient to improve the strength

development of the mortar.

[0007]

Therefore, as a result of detailed examination of

components in a cement composition, the present inventors

have found that when examining a content of each compound

in 3CaO-SiO2 (abbreviation: C 3 S) and 2CaO-SiO2

(abbreviation: C 2 S), a cement clinker composition capable of

improving strength development of mortar while suppressing

an increase in environmental burden can be obtained.

That is, the present invention provides the following

[1] to [3].

[1] A cement clinker including:

3CaO•SiO2 in a proportion, calculated by Bogue

formula, of 50.0% by mass or more and 75.0% by mass or

less;

2CaO•SiO2 in a proportion, calculated by Bogue

formula, of 5.0% by mass or more and 25.0% by mass or less;

MgO;

Na20; and

MnO,

wherein Formula (1) is satisfied.

MgOC 3 Sx (-0. 6)+Na 2 OC 3 Sx (15. 3)+MgOC 2 SX (-6. 9) +Na 2 OC 2 SX(5.2)+MnOC 2SX(145.7) 5.700 •••(1)

In the formula,

MgOC 3 S represents a content (% by mass) of MgO in

3CaO-SiO 2 ,

Na2O_C 3 S represents a content (% by mass) of Na20 in

3CaO-SiO 2 ,

MgOC 2 S represents the content (% by mass) of MgO in

2CaO -SiO 2 ,

Na2O_C 2 S represents the content (% by mass) of Na20 in

2CaO-SiO2, and

MnOC 2 S represents the content (% by mass) of MnO in

2CaO-SiO 2 .

[2] The cement clinker according to [1], in which

Formula (2) is further satisfied.

MgOC 2 S X (-6. 9) +Na 2 O C 2 S X (5.2) +MnOC 2 S X (145. 7) 2; 4. 600 • (2)

[3] A cement composition including:

the cement clinker according to [1] or [2]; and

gypsum.

Advantageous Effects of Invention

[0008]

According to the present invention, it is possible to

obtain a cement clinker and a cement composition capable of

improving strength development of mortar while suppressing

an increase in environmental burden.

Description of Embodiments

[0009]

Hereinafter, a cement clinker and a cement composition

of the present invention will be described in detail.

[0010]

[Cement clinker]

The cement clinker of the present invention is

preferably used for ordinary Portland cement.

[0011]

The cement clinker of the present invention is a main

component forming a cement composition, and is manufactured

by blending limestone (CaO component), clay (A1 2 0 3 component and SiO2 component), silica stone (SiO2 component), an iron oxide raw material (Fe203 component), and the like and firing. The cement clinker of the present invention may contain industrial waste or the like such as coal ash, construction-generated soil, steelmaking slag, blast furnace slag, converter slag, by-product gypsum, municipal waste incineration ash, and a by-product produced during a production process, as raw materials.

Contents of SiO 2 , A1 2 0 3 , Fe203 and CaO are measured

according to JIS R 5204:2019 "Analysis method for cement by

X-ray fluorescence".

[0012]

The content of the SiO 2 of the cement clinker of the

present invention is preferably 15.00% by mass or more,

more preferably 17.00% by mass or more, and still more

preferably 18.00% by mass or more, and is preferably 30.00%

by mass or less, more preferably 25.00% by mass or less,

and still more preferably 23.00% by mass or less.

[0013]

The content (WA1203% by mass) of the A1 2 0 3 of the cement

clinker of the present invention is preferably 2.00% by

mass or more, more preferably 4.00% by mass or more, and

still more preferably 4.50% by mass or more, and is

preferably 10.00% by mass or less, more preferably 8.00% by mass or less, and still more preferably 7.00% by mass or less.

[00141

The content (WFe203% by mass) of the Fe203 of the cement

clinker of the present invention is preferably 1.00% by

mass or more, more preferably 1.50% by mass or more, and

still more preferably 2.00% by mass or more, and is

preferably 10.00% by mass or less, more preferably 7.00% by

mass or less, and still more preferably 5.00% by mass or

less.

[0015]

The content of the CaO of the cement clinker of the

present invention is preferably 50.00% by mass or more,

more preferably 55.00% by mass or more, and still more

preferably 60.00% by mass or more, and is preferably 80.00%

by mass or less, more preferably 75.00% by mass or less,

and still more preferably 70.00% by mass or less.

[0016]

The cement clinker of the present invention contains

MgO, Na20, and MnO, as trace components. Each content of

the MgO, the Na20, and the MnO is measured in accordance

with JIS R 5204:2019 "Analysis method for cement by X-ray

fluorescence".

The MgO is introduced into the cement clinker, for

example, by using a slag containing a large amount of MgO

as a raw material for the cement clinker.

The Na20 is introduced into the cement clinker, for

example, by using construction-generated soil as a raw

material for the cement clinker.

The MnO is introduced into the cement clinker by

using, for example, a blast furnace slag and a converter

slag as raw materials for the cement clinker.

[0017]

The content (Wmgo% by mass) of the MgO of the cement

clinker of the present invention is preferably 0.05% by

mass or more, more preferably 0.2% by mass or more, and

still more preferably 0.5% by mass or more, and is

preferably 5.00% by mass or less, more preferably 3.00% by

mass or less, and still more preferably 2.5% by mass or

less.

[0018]

The content (WNa20% by mass) of the Na20 of the cement

clinker of the present invention is preferably 0.10% by

mass or more and more preferably 0.15% by mass or more, and

is preferably 1.00% by mass or less, more preferably 0.80%

by mass or less, and still more preferably 0.50% by mass or

less.

[0019]

The MnO content (WMno% by mass) of the cement clinker

of the present invention is preferably 0.01% by mass or

more and more preferably 0.02% by mass or more, and

preferably 0.50% by mass or less, more preferably 0.30% by

mass or less, and still more preferably 0.20% by mass or

less.

[0020]

In 3CaO-SiO2 (abbreviation: C 3 S) and 2CaO-SiO2

(abbreviation: C 2 S) in the cement clinker of the present

invention, MgOC 3 S (content (% by mass) of MgO in

3CaO-SiO2), Na2O_C 3 S (content (% by mass) of Na20 in

3CaO-SiO2), MgOC 2 S (content (% by mass) of MgO in

2CaO-SiO2), Na2O_C 2 S (content (% by mass) of Na20 in

2CaO-SiO2), MnOC 2S (content (% by mass) of MnO in

2CaO-SiO2) satisfy the relationship of Formula (1).

These contents are determined by an EPMA measurement

to be described later.

[0021]

[0022]

Non Patent Literature No. 2 examines the mineral

composition of C 3 S and C 2 S based on a composition of the

TiO 2 and the MgO in the cement clinker as described above.

However in the present invention, by examining a chemical

composition in C 3 S and C 2 S, the strength development of the

mortar manufactured from the cement clinker is improved.

The chemical composition of the C 3 S and the C 2 S can be

appropriately adjusted depending on raw materials to be

used and combinations thereof.

[0023]

A left side of Formula (1) is 5.700 or more, and from

a viewpoint of the strength development of the mortar,

preferably 5.900 or more, more preferably 6.000 or more,

and still more preferably 6.100 or more.

An upper limit of the left side of Formula (1) is not

particularly limited, and from the viewpoint of ease of

procurement and manufacture of raw materials, is more

preferably 12.000 or less, still more preferably 11.000 or

less, and still more preferably 10.000 or less.

[0024]

The MgOC 3 S is adjusted together with other components

according to the value on the left side of Formula (1), and

is preferably 0.100 or more, more preferably 0.300 or more,

and still more preferably 0.400 or more and more preferably

2.000 or less, still more preferably 1.500 or less, and

still further preferably 1.000 or less.

[0025]

The Na20_C 3 S is adjusted together with other

components according to the value on the left side of

Formula (1), and is preferably 0.050 or more, more

preferably 0.070 or more, and still more preferably 0.080

or more and more preferably 1.000 or less, still more

preferably 0.500 or less, and still further preferably

0.300 or less.

The MgOC 2 S is adjusted together with other components

according to the value on the left side of Formula (1), and

is preferably 0.010 or more, more preferably 0.100 or more,

and still more preferably 0.200 or more and more preferably

2.000 or less, still more preferably 1.000 or less, and

still further preferably 0.700 or less.

[0026]

The Na20_C 2 S is adjusted together with other

components according to the value on the left side of

Formula (1), and is preferably 0.050 or more, more

preferably 0.100 or more, and still more preferably 0.200

or more and more preferably 2.000 or less, still more

preferably 1.200 or less, and still further preferably

0.800 or less.

The MnOC 2 S is adjusted together with other components

according to the value on the left side of Formula (1), and

is preferably 0.001 or more, more preferably 0.010 or more,

and still more preferably 0.020 or more and more preferably

0.200 or less, still more preferably 0.100 or less, and

still further preferably 0.070 or less.

[0027]

The cement clinker of the present invention contains

3CaO-Al 20 3 (abbreviation: C 3 A) and 4CaO-Al 20 3 -Fe2O3

(abbreviations: C 4AF), in addition to the 3CaO-SiO2

(abbreviation: C 3 S) and the 2CaO-SiO2 (abbreviation: C 2 S).

The cement clinker is formed of main minerals of alite (C3 S)

and belite (C 2 S) and an interstitial phase or the like of an

aluminate phase (C 3 A) and a ferrite phase (C 4 AF) existing

between crystals of the main minerals.

[0028]

Proportions of C3S, C 2 S, C 3 A, and C 4 AF in the cement

clinker are determined from proportions of CaO, SiO 2 , A1 2 0 3

, and Fe203, measured by JIS R 5204:2019 "Analysis method for

cement by X-ray fluorescence" in cement clinker, by a

calculation called Bogue formula in a field of cement

chemistry (for example, see "Science of Cement", translated

by Masaki Daimon, Uchida Old Tsuruno (1989), p. 11).

[0029]

The proportion of the 3CaO-SiO2 calculated by the

Bogue formula in the cement clinker of the present

invention is preferably 50.0% by mass or more, more preferably 52.0% by mass or more, still more preferably

54.0% by mass or more because the strength development of

the concrete and the mortar manufactured by using the

cement clinker can be set to a practical level, and is more

preferably 75.0% by mass or less, more preferably 70.0% by

mass or less, and still more preferably 65.0% by mass or

less because the heat of hydration of the cement

composition can be suppressed.

[00301

The proportion of the 2CaO-SiO2 calculated by the

Bogue formula in the cement clinker of the present

invention is preferably 5.0% by mass or more, more

preferably 10.0% by mass or more, and still more preferably

15.0% by mass or more because it is suppressed that

3CaO-SiO2 increases and the heat of hydration of the cement

composition becomes too high, and is preferably 25.0% by

mass or less, and more preferably 24.0% by mass or less

because the short-term strength of concrete and mortar

manufactured by the cement clinker can be raised to a

practical level or higher.

[0031]

<Total proportion of 3CaO-Al2O3 (C 3 A) and

4CaO-Al 20 3 -Fe2O3 (C 4AF)>

A total proportion of 3CaO-Al2O3 and 4CaO-Al2O3-Fe2O3 calculated by the Bogue formula in the cement clinker of the present invention is preferably 15.0% by mass or more, more preferably 16.0% by mass or more, and still more preferably 17.0% by mass or more, because when the amount of a liquid phase generated during the calcining of the cement clinker composition is small, the solid-phase-liquid phase reaction due to the intervention of the liquid phase does not proceed rapidly, and the calcining of the cement clinker composition may be insufficient, and the calcining of the cement clinker composition may be insufficient, and also dust is scattered during the cement kiln and the radiant heat from a burner is blocked, so calcining of the cement clinker may not be performed efficiently, and is preferably 22.0% by mass or less and more preferably 21.0% by mass or less, because the short-term strength of concrete and mortar produced using the cement clinker can be set to a practical level or higher.

[0032]

The proportion of the 3CaO-A1203 calculated by the

Bogue formula in the cement clinker of the present

invention is preferably 3.0% by mass or more, more

preferably 5.0% by mass or more, and still more preferably

7.0% by mass or more, because the decrease in viscosity of

the liquid phase generated during calcining of cement clinker is suppressed, the granulation of cement clinker is appropriately proceeded, it is suppressed that a layer pressure in the clinker cooler becomes unstable due to decrease in the particle size of cement clinker and the heat of hydration can be reduced, and is preferably 15.0% by mass or less and more preferably 12.0% by mass or less, because the layer pressure in the clinker cooler becomes constant, and the cement clinker can be quenched.

[00331

The proportion of the 4CaO-Al2O3-Fe2O3 calculated by

the Bogue formula in the cement clinker of the present

invention is preferably 5.0% by mass or more, more

preferably 7.0% by mass or more, and still more preferably

8.3% by mass or more because the heat of hydration of the

cement composition can be suppressed, and is preferably

13.0% by mass or less and more preferably 11.0% by mass or

less because the short-term strength of concrete and mortar

manufactured by the cement clinker can be raised to a

practical level or higher.

[0034]

It is also preferable that MgOC 2 S, Na20_C 2 S and

MnOC 2 S in C 2 S of the cement clinker of the present

invention satisfy the relationship of Formula (2).

[0035]

MgOC 2 S X (-6. 9) +Na 2OC 2 S X (5. 2) +MnOC 2 S X (145. 7) 4. 600 ••(2)

[0036]

A left side of Formula (2) is, from a viewpoint of the

strength development of the mortar, preferably 4.600 or

more, more preferably 4.700 or more, and still more

preferably 4.800 or more.

An upper limit of the left side of Formula (2) is not

particularly limited, and from the viewpoint of ease of

procurement and manufacture of raw materials, is more

preferably 10.000 or less, still more preferably 9.000 or

less, and still further preferably 8.500 or less.

[0037]

[Method for manufacturing cement clinker]

A clinker of the present invention can be

manufactured, for example, as follows.

As a clinker raw material, those containing at least

Mg, Na, and Mn, in addition to Ca, Si, Al, and Fe are used.

As long as the raw material contains the above elements,

any form thereof such as an elemental substance, an oxide,

a carbon oxide can be used and mixtures thereof can be

used. Examples of natural raw materials include limestone,

clay, silica stone, and iron oxide raw materials. Examples

of industrial raw materials include waste raw materials containing the above elements, a blast furnace slag, fly ash, and the like. Regarding the mixing proportion of the clinker raw material, it is preferable to mix the raw material so as to have a component composition corresponding to the target Bogue formula value and satisfy

Formula (1).

[00381

Then, the clinker raw material mixed in a composition

so as to obtain the targeted clinker is calcinated under a

normal calcining condition and cooled. Firing is usually

performed using an electric furnace, a rotary kiln, or the

like. Examples of a calcining method include a method

including: a first calcining step in which a clinker raw

material is heated and calcinated at a predetermined first

calcining temperature for a first calcining time; a

temperature raising step of raising a temperature, after

the first calcining step, from the first calcining

temperature to a predetermined second calcining temperature

over a predetermined temperature raising time; and a second

calcining step of heating and calcining, after the

temperature raising step, at the second calcining

temperature for a predetermined second calcining time.

The temperature and time of each step may be the

conditions usually carried out, and the cement clinker can

be manufactured by quenching the calcined product.

[0039]

[Cement composition]

The cement composition of the present invention

contains the cement clinker and gypsum. The Blaine's

specific surface area of the cement used in the present

invention is preferably 3000 cm 2 /g or more and 3400 cm 2 /g or

less, and more preferably 3100 cm 2 /g or more and 3300 cm 2 /g

or less.

[Gypsum]

A proportion of the gypsum in the cement composition

of the present invention is preferably 0.5% to 2.5% by

mass, and more preferably 1.0% to 1.8% by mass in terms of

SO 3 equivalent. When setting the proportion of the gypsum

to the range, drying shrinkage of the cement composition

can be made appropriate, and strength exhibited by the

cement composition can be increased. A proportion of SO 3 in

the gypsum can be measured in accordance with JIS R

5202:2010 "Chemical analysis method for Portland cement". A

proportion of the mass of the gypsum converted to SO 3 in the

cement composition can be determined from a blending amount

of the gypsum and the proportion of the SO 3 contained in the

gypsum.

As the gypsum, any of anhydrous gypsum, hemihydrate

gypsum, and dihydrate gypsum can be used.

[0040]

Fly ash, blast furnace slag, silica fume, or the like

can be further added to the cement composition of the

present invention in order to control fluidity, a hydration

rate, or strength development. Further, an AE water

reducing agent, a high-performance water reducing agent, or

a high-performance AE water reducing agent, particularly a

polycarboxylate-based high-performance AE water reducing

agent, can be added to the cement composition of the

present invention.

[0041]

[Mortar and concrete]

Cement milk can be prepared by mixing the cement

composition of the present invention with water, mortar can

be prepared by mixing with water and sand, and concrete can

be manufactured by mixing sand and gravel. Further, when

producing the mortar or the concrete from the cement

composition, a blast furnace slag, fly ash, or the like can

be added.

Examples

[0042]

Hereinafter, the present invention will be described

in more detail with reference to examples. However, the

present invention is not limited to the following examples.

1. Measurement and evaluation

1-1. Clinker composition

A chemical composition (content rate of each

component) in cement clinkers of Examples and Comparative

Examples was measured in accordance with JIS R 5204:2019

"Analysis method for cement by X-ray fluorescence". Results

are shown in Table 1.

A mineral composition was calculated from the obtained

mass proportions of CaO, SiO 2 , A1 2 0 3 , and Fe203 by using the

following Bogue formula. Results are shown in Table 2.

C3S = (4.07 x CaO) - (7.60 x SiO 2 ) - (6.72 x A1 2 0 3 )

(1.43 x Fe203)

C2S = (2.87 x SiO 2 ) - (0.754 x C3S)

C 3A = (2.65 x A1 2 0 3 ) - (1.69 x Fe203)

C 4 AF = 3.04 x Fe203

Further, the value on the left side of Formula (1) was

calculated using the obtained content rate of each

component. Results are shown in Table 3.

[0043]

1-2. EPMA measurement

The cement clinker of Examples and Comparative

Examples was pulverized to a particle size of about 1 to 2

mm to adjust the particle size. The obtained particles were

embedded in an epoxy resin, and then the resin surface was

mirror-polished. After the mirror polishing, carbon vapor

deposition was performed on the resin surface to produce a sample for EPMA measurement.

An EPMAJXA-8200 manufactured by JEOL Ltd. was used as

a measuring device, and a structure image of the cement

clinker particles on the mirror surface of the sample was

observed under the following conditions. In the structure

image, each mineral was specified based on the

characteristics of above (a) to (d).

Each mineral was identified based on characteristics

of (a) to (d).

(a) C3S: Polygonal particle, light gray, and tens of

Pm

(b) C2S: Elliptical particle, dark gray, and tens of

Pm

(c) C 3 A: Amorphous structure observed between silicate

phases, dark gray, and several pm to a dozen pm

(d) C4AF: Amorphous structure observed between

silicate phases, white, and several pm to a dozen pm

A characteristic X-ray was analyzed at 20 points for

each of the four minerals, with acceleration voltage: 15

kV, irradiation electric current: 3.0 x 10 -8 A, beam

diameter: about 1 pm, and a correction calculation method:

oxide-ZAF method.

Among these, for C 3 S, the analysis points within the

range of 2.7 < CaO content rate (%)/SiO 2 content rate (%) <

3.3 were adopted, and the average value obtained was adopted as the chemical composition (% by mass) in C 3 S.

Among these, for C 2 S, the analysis points within the

range of 1.8 < CaO content rate (%)/SiO 2 content rate (%) <

2.5 were adopted, and the average value obtained was

adopted as the chemical composition (% by mass) in C2S.

[0044]

1-3. Mortar strength at 28 days of age (strength

development, 28d strength)

For the mortar strength at 28 days of age using the

cement clinker of Examples and Comparative Examples,

according to JIS R 5201 "Physical test method for cement:

10. 4 Method for producing specimens", mortar prepared from

cement compositions was placed in three metal molds of 40 x

40 x 160 mm, respectively, and 24 hours later, the mold was

removed to prepare three mortar specimens. The material was

cured in water at 200C until 28 days of age, and the

compressive strength was measured according to JIS R 5201

"Physical test method for cement: 10.5 measurement".

[0045]

1-4. Setting measurement method

The cement paste was prepared according to JIS R

5201:2015 "Physical testing methods for cement", the

standard soft water amount was determined, and then the

start time and end time were measured with the standard

soft paste.

[00461

2. Preparation of cement composition

2-1. Clinker

As raw materials for the cement clinker, calcium

carbonate (manufactured by Kishida Chemical Co., Ltd.,

reagent first grade, CaCO3), silicon dioxide (manufactured

by Kanto Chemical Co., Ltd., reagent first grade, SiO 2 ),

aluminum oxide (manufactured by Kanto Chemical Co., Ltd.,

reagent first grade, A1 2 0 3 ), iron oxide (III) (manufactured

by Kanto Chemical Co., Ltd., reagent special grade, Fe203),

basic magnesium carbonate (manufactured by Kishida Chemical

Co., Ltd., reagent special grade, 4MgCO3-Mg(OH)2-5H20),

sodium carbonate (manufactured by Kishida Chemical Co.,

Ltd., special grade, Na2CO3), potassium carbonate

(manufactured by Kanto Chemical Co., Ltd., reagent first

grade, K 2 CO3 ), calcium sulfate dihydrate (manufactured by

Kishida Chemical Co., Ltd., reagent first grade,

CaSO 4 -2H20), titanium dioxide (manufactured by Kanto

Chemical Co., Ltd., reagent special grade, TiO 2 ), tricalcium

phosphate (manufactured by Kishida Chemical Co., Ltd.,

reagent first grade, Ca3(PO4)2), manganese oxide

(manufactured by Kanto Chemical Co., Ltd., Cica first

grade, MnO2), and zinc oxide (manufactured by Kanto Chemical

Co., Ltd., reagent special grade, ZnO) were used.

[0047]

The raw materials blended with varying the blending

amount were put into an electric furnace and calcined at

10000C for 30 minutes. Then, a temperature was raised from

10000C to 14500C over 45 minutes, and further calcined at

14500C for 30 minutes.

Then, the calcined product was quenched by taking the

calcined product into an atmosphere to prepare cement

clinkers of Examples 1 to 6 and Comparative Example 1.

[0048]

2-2. Preparation of cement composition

Semi-hydrated gypsum (manufactured by Kanto Chemical

Co., Inc., semi-hydrated gypsum, model number: 07108-01

(calcined gypsum deer first grade) with SO 3 equivalent

amount of 1.5% by mass) was blended with the prepared

cement clinker. The compound was pulverized with a ball

mill so that the Blaine's specific surface area value

became in a range of about 3200 ± 200 cm 2 /g to prepare

cement compositions of Examples 1 to 5 and Comparative

Examples 1 and 3.

[0049]

2-3. Preparation of mortar

Mortar was adjusted from the cement compositions of

Examples and Comparative Examples in accordance with JIS R

5201:2015 "Physical testing methods for cement". The

obtained mortar was cast into three metal molds having a size of 40 mm x 40 mm x 160 mm, and after 24 hours, the mortar was demolded to prepare three specimens.

cf)

m cn m - L)L 0> 0> 0 >, C) -0 Q 0 LC) 0C0 0 mLC)

cf)

CD D C C CDCD D D Dj -,C D m' Ln 0

m cnr)

0 c cC C c C1 C c c

00000 L0)0 0 0 Q0 m LC)

Q0 n )cfo> )) Ln cnr-cn cn)

U o0 r 0 KD

0 LC) M CD M 1D -- lh LC l 0 0 0 0- 00m

o C

I'l Q0 co m m 'l ~ 0 Oc -1 c m (D Lc) u L)K L0 > QjuC)LC)LC

0, "N LC 0 0LC

0 -0

oo M Q0 Q0 0o LC)Qo C) C~) LC L) L C) 0

M M CD Q(NL(N 0 0 m Q0

U)>0-, C CD KD 0

CD -1 ~ -1 4-1 4 1

CDDC 1 KD C

co co coQ)Q Q4 Q4H Q4- xxxx xF

A4 4 C0 C4 C0 (N 0 w ru~r u 09 09 0E

000n

4-w C C C DL) C D C

(n)-A m)0 0 0 Il Q0 cn~l -1 y -l ~0~ ~

OOAO l Q 0 (n -A-00 ( C

co

C

4- KDC')AAO (C) LC C) U)

0

CC CC)0 00-Am -0C 0 0D

CD 0Amm C C) [- m' (n

M '~ D - A C U)

0

AA C 00A 0 (n Q 0C An C

0)0) (n LC

A 4-

a)0

HOTI

(Df

(n rH4 a)> > ~ >(4 4) CD d CD IlHj Q C') - QQ Q K K

10 1 Li

[00531

In Examples 1 to 5 and Comparative Examples 1 to 3,

the TiO 2 focused on in Non Patent Literature No. 2 is set to

about 0.30% by mass, and evaluation results of the cement

clinker with the value on the left side of Formula (1) and

mortar using the same were obtained.

It was found that all of Examples 1 to 5 were superior

in 28d strength compared to Comparative Examples 1 to 3.

Further, in the invention described in Non Patent

Literature No. 1, the setting time was shortened by

changing the fineness and the mineral composition, but it

was confirmed that the setting time was not shortened in

the present invention as shown in Table 3.

[0054]

Example 2 is a cement clinker adjusted to satisfy

Formula (1) by decreasing MgOC 2 S and Na20C 2 S and

increasing MnOC 2 S from Example 1. Example 4 is a cement

clinker adjusted to satisfy Formula (1) by decreasing

Na20_C 3 S and Na20_C 2 S and increasing MnOC 2 S. In both cases,

the 28d strength became a large value.

In Example 3, MnOC 2 S was reduced from Example 1, but

the 28d strength became a large value by adjusting so as to

satisfy Formula (1).

[00551

As described above, it was found that when adjusting the MgO_C 3 S, the Na20_C 3 S, the MgO_C 2 S, the Na20_C 2 S, and the

MnOC 2 S so as to satisfy Formula (1), a cement clinker with

excellent properties can be obtained.

Claims

1. A cement clinker comprising:

3CaO•SiO2 in a proportion, calculated by Bogue

formula, of 50.0% by mass or more and 75.0% by mass or

less;

2CaO•SiO2 in a proportion, calculated by Bogue

formula, of 5.0% by mass or more and 25.0% by mass or less;

MgO;

Na20; and

MnO,

wherein Formula (1) is satisfied,

MgOC 3 S X (-O 6)+Na 2OC3S X (15. 3) +MgOC 2 S X (-6. 9) +Na 2 OC 2 S X (5. 2)+MnOC 2 S X (145. 7) 5. 700 . (1)

in the formula,

MgOC 3 S represents a content (% by mass) of MgO in

3CaO -SiO2 ,

Na2O_C 3 S represents a content (% by mass) of Na20 in

3CaO -SiO2 ,

MgOC 2 S represents a content (% by mass) of MgO in

2CaO-SiO2,

Na2O_C 2 S represents a content (% by mass) of Na20 in

2CaO-SiO2, and

MnOC 2 S represents a content (% by mass) of MnO in

2CaO-SiO 2 .

2. The cement clinker according to claim 1,

wherein Formula (2) is further satisfied

MgO-C 2 S X(-6. 9) +Na 2OC 2 S X(5.2) +MnOC 2 S X(145, 7) 4. 600 ••(2)

3. A cement composition comprising:

the cement clinker according to claim 1 or 2; and

gypsum.