AU2014258396A1

AU2014258396A1 - Fluidity improvement type cement clinker

Info

Publication number: AU2014258396A1
Application number: AU2014258396A
Authority: AU
Inventors: Takashi CHABAYASHI; Hiroyoshi Kato; Akinori Nakamura; Shingo Yoshimoto
Original assignee: Tokuyama Corp
Current assignee: Tokuyama Corp
Priority date: 2013-04-24
Filing date: 2014-04-16
Publication date: 2015-11-05
Anticipated expiration: 2034-04-16
Also published as: WO2014175294A1; JP6353264B2; JP2014224033A; AU2014258396B2

Abstract

This Portland cement clinker, which has a hydraulic modulus of 1.8-2.2, a silica modulus of 2.0-2.8, an iron modulus of 1.7-2.0, and a TiO

Description

1 DESCRIPTION FLUIDITY IMPROVEMENT TYPE CEMENT CLINKER 5 TECHNICAL FIELD The present invention relates to Portland cement clinker. More specifically, it relates to cement clinker which provides a cement composition having excellent fluidity even when it contains TiO2 derived from a raw 10 material. BACKGROUND ART Portland cement clinker is essentially composed of SiO 2 , A1 2 0 3 , CaO and Fe 2

O

3 . These components are contained in the 15 clinker as minerals. More specifically, the minerals contained in the clinker are C 3 S (3CaO-SiO 2 ) , C3A (3CaO-Al 2 0 3 ) ,

C

2 S (2CaO-SiO2) and C 4 AF (4CaO-Al 2 O3-'Fe 2 O3), and it is well known that the existence ratio of these components has a great influence upon the physical properties of cement. 20 Various studies are being made on the influences of minor components contained in cement. For example, the content of magnesium oxide, the total content of alkalis and the content of a chloride ion in cement are specified by JIS standards (JIS R 5210). 25 The disposal of wastes and by-products is becoming a social problem. Examples of these include water sludge, incinerated ash of sewage sludge, incinerated ash of city garbage, blast furnace water granulated slag, blast furnace air-cooled slag and iron and steel slag. It is expected that 30 the number of types and the amounts of wastes and by-products which are difficult to be disposed of will increase in the future, and further studies on the establishment of effective methods for disposing of these and reusing and recycling methods are required.

2 For the manufacturing of cement, the above wastes and by-products have been recycled as raw materials and heat energy sources. However, there are many cases in which various components except for main components constituting 5 cement and minor components specified by JIS standards are contained in the above wastes and by-products in relatively large quantities. One of the components is a Ti component (chemical species containing a titanium atom) Especially when 10 neutralized slag (titanium slag) produced in the purif ication step of titanium is used as a cement raw material, the content of TiO 2 in the manufactured cement clinker often becomes about 1 mass%. Coal ash which is generally used as a cement raw material may contain a relatively large amount 15 of a Ti component (refer, for example, to JP-A 2010-120832) . In this respect, JP-A 2012-224503 reports that although the fluidity of cement degrades when it contains TiO 2 , the cement exhibits excellent fluidity by setting a specific iron modulus and a specific silica modulus even when 20 the content of TiO 2 becomes about 1 mass%. DISCLOSURE OF THE INVENTION However, since the presence ratio of clinker minerals has a great influence upon physical properties, when the iron 25 modulus and the silica modulus change, the physical properties of the obtained cement deviate from those of normal Portland cement. When a large amount of waste having a high content of a Ti component is used as a raw material, a cement composition having the same iron modulus and the 30 same silica modulus as those of normal Portland cement becomes unsatisfactory in terms of fluidity. The present invention was made to break through this situation. It is therefore an object of the present invention to provide cement clinker which provides a cement composition having excellent fluidity even when the content of Ti0 2 becomes high in the same mineral composition as that of normal Portland cement clinker. 5 The inventors of the present invention conducted intensive studies in view of the above problem. As a result, they found that excellent fluidity is ensured by adjusting the content of MnO ir cement clinker when the content of Ti0 2 is high in the same mineral composition as that of normal 10 Portland cement clinker. The present invention was accomplished based on this finding. That is, the present invention provides Portland cement clinker which has a hydraulic modulus of 1.8 to 2.2, a silica modulus of 2.0 to 2.8 and an iron modulus of 1.7 15 to 2.0 and contains 0.3 to 1.0 mass% of Ti0 2 and MnO in an amount which is 1.5 times or more the mass of TiO 2 . BEST MODE FOR CARRYING OUT THE INVENTION The Portland cement clinker of the present invention 20 (may also be simply referred to as "cement clinker" hereinafter) has a hydraulic modulus of 1. 8 to 2.2, a silica modulus of 2.0 to 2.8 and an iron modulus of 1.7 to 2.0. Preferably, it has a hydraulic modulus of 1. 9 to 2. 1, a silica modulus of 2.3 to 2.6 and an iron modulus of 1.8 to 2.0. 25 The above hydraulic modulus, silica modulus and iron modulus (three modulus) are calculated by inserting the results of chemical composition analysis obtained for cement clinker into the following equations, respectively, as is well known. 30 Hydraulic modulus = CaO/ (SiO 2 +Al 2 O3+Fe 2 03) Silica modulus = Si2/ (Al203+e 2 O3) iron modulus = A1203/ e203 In the above equations, the terms represented by the chemical formulas mean the contents of the species obtained 4 by the chemical composition analysis of the cement clinker (based on mass). The values of the above three modulus of the cement clinker of the present invention fall within the same ranges 5 as those of Portland cement clinker which exhibit normal properties. However, the cement clinker of the present invention contains 0.3 to 1.0 mass% of TiO 2 . It is known that when the cement clinker contains TiO 2 , the fluidity of the obtained 10 cement composition degrades. The present invention relates to a technology for restoring fluidity impaired by containing Ti0 2 by further containing MnO in cement clinker containing TiO 2 . When the content of TiO2 i~s lower than 0.3 mass%, the reduction of fluidity by TiC 2 can be substantially ignored 15 and accordingly, it is meaningless to apply the present invention. When the content of TiC 2 is higher than 1. 0 mass%, even if other requirements for the cement clinker of the present invention are satisfied, the restoration of fluidity in the obtained cement composition may become unsatisfactory, 20 thereby causing a big practical problem. The content of TiC 2 in the cement clinker of the present invention is preferably 0.5 to 1.0 mass%. The cement clinker of the present invention contains Mno in an amount which is 1.5 times or more the mass of Ti O2. 25 In this text, when the content of MnO satisfies the above requirement, fluidity which is degraded by the Ti component can be restored to such an extent that the cement clinker becomes industrially useful. Meanwhile, as the content of MnO becomes higher, the compressive strength of a hardened 30 body becomes lower. Therefore, the content of MnO is preferably not more than 2.5 mass%, more preferably not more than 2.0 mass%. The content of TiO2 and the content of MnO in this text are not limited to the contents of chemical species existent in the form of T102 and MnO, respectively. These values are calculated from the amounts of a titanium atom and a manganese atom determined by the chemical composition analysis of the cement clinker in terms of the masses of TiO 2 and Mno, 5 respectively. The chemical composition analysis (quantitative analysis) of components contained in the cement clinker may be carried out in accordance with, for example, the chemical analysis method specified in JIS R 5202 or the fluorescent 10 X-ray analysis method specified in JIS R 5204. The process for manufacturing the cement clinker of the present invention is not particularly limited. Since the three modulus of the cement clinker of the present invention fall within the same ranges as those of 15 conventionally known cement clinker having normal properties, as for the selection and preparation technology of main raw materials such as limestone and silica, conventionally known methods may be used as they are. Since the cement clinker of the present invention may 20 have a high content of TiO 2 it has an advantage that a large amount of waste containing a Ti component can be used as a raw material. A conventionally known process for producing cement clinker may be suitably selected and employed except that the blending ratio of the raw materials is adjusted by 25 further adding a suitable Mn source to the raw materials so as to ensure that cement clinker after burning has the above three modulus and the above content of TiO 2 and the above content of MnO. As the raw materials which can be used, not only natural 30 raw materials such as limestone, clay, silica stone and iron ore but also wastes and by-products may be used. Specific examples of the wastes and the by-products include blast furnace slag, steel slag, nonferrous slag, coal ash, sewage sludge, water purification sludge, paper making sludge, 6 construction generated soil, molding sand, dust, incineration fly ash, molten fly ash, wood, waste white clay, coal refuse, waste tires, shells, city garbage and incineration ash of city garbage (some of these become the 5 raw materials of the cement clinker and heat energy sources) . Raw materials having a high content of a Ti component include titanium slag, coal ash and blast furnace slag; and raw materials having a high content of a Mn component (chemical species containing a manganese atom) used to set 10 the content of MnO to the above range include manganese minerals and waste batteries. The Ti component and the Mn component contained in the raw materials are often contained in a form (for example, oxide, composite oxide or alloy) having almost no volatility 15 at a clinker burning temperature. Therefore, calculation may be carried out to determine the blending ratio based on the condition that all of titanium atoms and manganese atoms contained in the Ti component and the Mn component contained in the raw materials move into cement clinker. When it is 20 known in advance that there are/is a Ti component and/or a Mn component which volatilize in the raw material grinding step or burning step and are not introduced into the cement clinker, calculation must be carried out by taking this into consideration as a matter of course. When calculation is 25 carried out in accordance with a determined method for the control of composition at the time of manufacturing cement clinker, the composition of components of the cement clinker after burning can be generally controlled to a range of calculated valuetO.05 mass%. 30 Cement clinker can be obtained by burning the raw materials whose blending ratio has been adjusted as described above in accordance with a determined method in the industry. The burning method is not particularly limited, and a conventionally known method is suitably selected to burn the raw materials. For example, a cement kiln such as NSP kiln or SP kiln which is capable of high -temperature heating is used to burn the raw materials at a temperature of 1, 450'C or higher for preferably 20 to 120 minutes. 5 The cement clinker manufactured as described above may be used as a JIS-standard cement composition, a cement composition based on standards other than JIS standards or the raw material of a cement-based solidifying agent in accordance with a known method. 10 The JIS-standard cement composition or the cement composition based on standards other than JIS standards preferably contains at least a ground product of the cement clinker manufactured as described above and a ground product of gypsum. In addition to these, the composition may contain 15 a ground product of at least one selected from blast furnace slag, limestone (calcium carbonate) , f-y ash and silica fume. The content of a ground product of gypsum in the above cement comnposition is preferably 0.5 to 5 parts by mass, more preferably 1.5 to 3 parts by mass in terms of SO 3 based on 20 100 parts by mass of a ground product of the cement clinker. The preferred contents of other components based on 100 parts by mass of a ground product of the cement clinker are given below. Blast furnace slag: preferably not more than 70 parts by mass, 25 more preferably 0.5 to 60 parts by mass, much more preferably 0.5 to 30 parts by mass Limestone (calcium carbonate) : preferably not more than 30 parts by mass, more preferably 0.5 to 10 parts by mass Fly ash: preferably not more than 50 parts by mass, more 30 preferably 0.5 to 30 parts by mass Silica fume: preferably not more than 20 parts by mass, more preferably 0.5 to 10 parts by mass The above cement composition may be produced by grinding the above components after they are mixed together, 8 mixing the components after they are each ground, or a combination of these methods. A suitable grinding aid may be added at the time of grinding. The above cement composition has a Blaine specific 5 surface area of preferably not less than a value determined by JIS standards, more preferably 2, 800 to 5, 000 cm/g. This specific surface area can be achieved by suitably adjusting the degree of the above grinding. The cement composition obtained as described above may 10 be used to produce a hardened body by adding water directly or after it is mixed with a suitable material such as an aggregate or water reducing agent and may also be used as blast furnace slag cement or fly ash cement by mixing blast furnace slag or fly ash. 15 EXAMPLES Although the constitution and effect of the present invention will be explained with reference to the following examples, it is to be understood that the present invention 20 is not limited to these examples. The following reagents were used as the raw materials of the cement clinker in the following examples and comparative examples. 25 TiO 2 source: titanium dioxide (special grade) of Wako Pure Chemical Industries, Ltd. CaO source: calcium carbonate (special grade) of Wako Pure Chemical Industries, Ltd. SiC 2 source: silicon dioxide (special grade) of Wako Pure 30 Chemical Industries, Ltd. Al 2

O

3 source: aluminum oxide (special grade) of Wako Pure Chemical Industries, Ltd. Fe 2 O3 source: iron oxide (first grade) of Wako Pure Chemical Industries, Ltd.

9 MnO source: manganese oxide (first grade) of Wako Pure Chemical Industries, Ltd. The gypsum used to prepare the cement composition was byproduct gypsum generated from a thermal power plant. 5 Reference Example, Examples i to 5 and Comparative Examples I to 5 (1) Preparation of cement clinker and analysis of composition 10 The above cement composition raw materials were fed to an electric furnace and fully mixed together to ensure that the contents of C3S, C 2 S, C 3 A and C 4 AF calculated by Bogue' s equations and also the contents of TiO 2 and MnC became values shown in Table i below and burned in the atmosphere 15 at 1,450'C for 1.5 hours to obtain cement clinker. The chemical composition obtained by fluorescent X-ray analysis based on JIS R 5204 of the cement clinker obtained above, the three modulus calculated from the composition and the composition of clinker minerals obtained by inserting 20 the composition into the Bogue' s equations are shown in Table (2) Preparation of cement composition and measurement of cement paste flow 25 After gypsum was added to the cement clinker obtained above to ensure that the content of S03 became 1. 8 to 1. 9 mass%, the resulting product was ground by using a ball mill to ensure that its Blaine specific surface area became 3,200 to 3,300 cm 2 /g to prepare a cement composition. 30 A cement paste flow of the cement composition obtained above was measured right after kneading under the conditions of a water/cement ratio of 0.50, a kneading time of 3 minutes and a testing temperature of 20 'C without adding an admixture in accordance with JASS 15 M-103. The measurement results 10 are shown In Table 1.

4-) r- 0 - 0 0 0 0 10 a a- a --- A S 0 0 10 0 0o 0 01'0 0 0 l0 ) n- qi - rii - - I H H-4i H mi iJ f' ----- E2 0 ~ i f U) 5 iI~ f 0 o i 4-) 0H o 0 0 C)~ H H Ht' H Ht H HA H H H H1 ci) 1- D (0 0 "q LO it5 SD k0 LO ID rD SD n D - (0 u' 6 4- 1 44) M: ~ N N ( p0: co m2 w2 o 00 co 00 00 co 002 1 N Tj 00 ___ I, i (n) ci) 00c,-o r- r r r-4 02 N 1 1S . N N N 0 c 024 024 N, N' NI4.C4 P4-; F-fC C) N N N N C ( N (N C N C4 TH H:H HA - H H Hl H- Hi H I 4- (Y0:(Y 5D4 U)---------- CA 0o co- - r- r- r- W 42V Hn O H H H 0H H Ho HO H o o 5 ~ '' (N CH N N N A' -4( H N A( C\1 cC 2 4 N IN IN N N N N ND ND 0 C14 LI 1-- U) mI W LI mI I mI rl OH 0 to 0 En LO (1 SD (N H O2 0 L O -H

------

(N-H

---

li0 si) (N4 (N0 H H H HN 0 m__ LO U)LO o o 0 0( o o (N CC N L C;) r-4 HI r-I H 'Yf N (0 IN --- 4 M3 I - --------- 12 Reference Example is an example of normal Portland cement having no Ti02. In Comparative Examples i to 5, the content of Ti0 2 is 0.5 mass% and 1.0 mass%, respectively. The cement paste flow values of these comparative examples 5 are smaller than that of the reference example. In contrast to this, in Examples 1 to 5 in which MnO is contained in an amount which is 1.5 times or more the mass of Ti0 2 , it is understood that a large flow value is obtained even when TiC 2 is contained. 10 Effect of the Invention According to the present invention, even when TiC 2 is contained in cement clinker by using a recycled raw material, a cement composition having excellent fluidity can be 15 obtained by increasing the content of MnO in the clinker. Therefore, it is possible to use a raw material having a high content of a Ti component. in a larger amount than before, thereby promoting the effective use of waste.

Claims

1. Portland cement clinker having a hydraulic modulus of 1.8 to 2.2, a silica modulus of 2.0 to 2.8 and an iron modulus 5 of 1. 7 to 2. 0 and a Ti'2 content of 0. 3 to 1. 0 mass% and containing MnO in an amount which is 1.5 times or more the mass of Ti02

2. The Portland cement clinker according to claim 1, 10 wherein the content of MnO is 1. 5 to 2. 5 times the mass of TiO2.

3. A cement composition comprising a ground product of the Portland cement clinker of claim 1 or 2 and a ground 15 product of gypsum.

4. The cement composition according to claim 3 which further comprises a ground product of at least one selected from blast furnace slag, limestone, fly ash and silica fume.