Scholarly article on topic 'Advances in the Use of the Steel Industry by-products when Manufacturing Traditional Ceramics for Sustainable Purposes'

Advances in the Use of the Steel Industry by-products when Manufacturing Traditional Ceramics for Sustainable Purposes Academic research paper on "Materials engineering"

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{"Traditional ceramics" / "blast furnace slag" / "sustainable manufacturing."}

Abstract of research paper on Materials engineering, author of scientific article — J.L. Mendoza-Cuenca, M. Mayorga, L. Romero-Salazar, H.T. Yee-Madeira, J. Jiménez-Gallegos, et al.

Abstract The ceramic industry is not only one of the most profitable worldwide industries, but also a large carbon footprint one, mainly due to the use of virgin raw non-renewable materials and high consumption of fuels. On the other hand, the steel industry produces by-products as blast furnace and electric arc furnace slag that can be recycled in other manufactures. These slags are mainly composed of alumina, silica, calcium oxide, magnesium oxide and iron oxide, which are some of the components of ceramic raw materials. Blast furnace slag is widely used in the cement industry as a clinker replacement for the manufacturing of the Composite Portland Cement, a less carbon footprint product when compared besides Ordinary Portland Cement. In this research, we communicate some preliminary laboratory-scale results when including steel slags in traditional processes of ceramic manufacturing. We completely replaced kaolin by slag and designed different ceramic compound mix formulations. We report some fresh and sintered properties such as dry shrinkage and porosity. This investigation is part of a major project focused on the development of a methodology for the utilization of steel by-products in the industrial-level manufacturing of traditional ceramic products especially tiles and building bricks.

Academic research paper on topic "Advances in the Use of the Steel Industry by-products when Manufacturing Traditional Ceramics for Sustainable Purposes"

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Procedía Engineering 118 (2015) 1202 - 1207

Procedía Engineering

www.elsevier.com/locate/procedia

International Conference on Sustainable Design, Engineering and Construction

Advances in the use of the steel industry by-products when manufacturing traditional ceramics for sustainable purposes

Mendoza-Cuenca, J.L.a, Mayorga, Mb., Romero-Salazar, L.b, Yee-Madeira H.T.c, Jiménez-Gallegos J.c and Arteaga-Arcos, J.C.b*

aDoctorado en Diseño, Facultad de Arquitectura y Diseño, UAEMex, Toluca C.P. 50130, México bFacultad de Ciencias, UAEMex, Toluca C.P. 50200, México bEscuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, México D.F C.P. 07738, México

Abstract

The ceramic industry is not only one of the most profitable worldwide industries, but also a large carbon footprint one, mainly due to the use of virgin raw non-renewable materials and high consumption of fuels. On the other hand, the steel industry produces by-products as blast furnace and electric arc furnace slag that can be recycled in other manufactures. These slags are mainly composed of alumina, silica, calcium oxide, magnesium oxide and iron oxide, which are some of the components of ceramic raw materials. Blast furnace slag is widely used in the cement industry as a clinker replacement for the manufacturing of the Composite Portland Cement, a less carbon footprint product when compared besides Ordinary Portland Cement. In this research, we communicate some preliminary laboratory-scale results when including steel slags in traditional processes of ceramic manufacturing. We completely replaced kaolin by slag and designed different ceramic compound mix formulations. We report some fresh and sintered properties such as dry shrinkage and porosity. This investigation is part of a major project focused on the development of a methodology for the utilization of steel by-products in the industrial-level manufacturing of traditional ceramic products especially tiles and building bricks.

© 2015Published byElsevier Ltd.Thisisanopen access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Peer-review under responsibility of organizing committee of the International Conference on Sustainable Design, Engineering and Construction2015

Keywords: Traditional ceramics; blast furnace slag; sustainable manufacturing.

* Corresponding author. Tel.: +52 (722) 2565556 x 124; fax: +52 (722) 2565554. E-mail address: jcarteaga@y ahoo. com.mx

1877-7058 © 2015 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Peer-review under responsibility of organizing committee of the International Conference on Sustainable Design, Engineering and Construction 2015 doi:10.1016/j.proeng.2015.08.464

1. Introduction

There is currently a huge worldwide need to recycle waste from multiple industrial activities of the human being. One of these industrial residues is a by-product from the steel industry; the blast furnace slag. Blast furnace slag is obtained by smelting iron ore in an electric blast furnace. Commonly it contains at least two-thirds by mass of glassy slag. Its major constituents are alumina (Al2O3), silica (SiO2), calcium oxide (CaO), magnesium oxide (MgO) and iron oxide (Fe2O3) [1]. In order to illustrate the use of iron by-products, in cement industry, these slag are used as a clinker replacement for the manufacturing of the Composite Portland Cement and also the so-called green cements, these environmentally friendly cements are used all around the world being less carbon footprint and less expensive products when compared against Ordinary Portland Cement [2, 3]. The alternative of using steel slag as a replacement of raw material for the manufacturing of traditional ceramic is a little-studied topic, even though the constituents of the slag are some of the most common components of clay ceramic raw materials.

Particularly, in Mexico the ceramic industry utilizes clay, silica (quartz), calcium carbonate, kaolin and feldspars in order to formulate the ceramic compound mix. The amount of each component is strongly dependent of the sintering temperature, the manufacturing process and the kind of ceramic piece to be fabricated; all these facts develop formulas for the industry of tiles that may differ from formulations used in other pottery manufacture. After a careful state-of-the-art review, we identify some previously reported studies regarding the employment of blast furnace slag as replacement in the formulation of ceramic compound mix. In Mexico, Osuna et al. reported the successful inclusion of slag for the manufacture, at laboratory level, of ceramic tiles; in that research they partially replaced different amounts of kaolin by slag [4]. Other reports have been conducted worldwide since roughly ten years ago. In some cases the investigations were focused in the substitution of the feldspars by slag, in such a case, the conclusion was that it is not recommended to conduct this change because the slag behaves as a refractory instead of as a flux, which is the objective of the usage of feldspars [5]. Other works reported the inclusion of the substitution of clay for different amounts of slag into the ceramic compound mix [6].

In this research work, we communicate some preliminary laboratory-scale results of the inclusion of slag in the process of traditional ceramic manufacturing. The component we selected for total substitution was the kaolin (2SiO2.Al2O3.2H2O), since this is the most expensive constituent of the formulation, and also because the slag is mostly composed by alumina (Al2O3) and silica (SiO2), which are the present oxides of kaolin. The amount of slag content in a triaxial design (in this case slag, clay and quartz) was varied from 10% to 50%.

2. Experimental study

The clay was obtained from a mine located at Lerma, a town near Toluca city in central México. Commercially available quartz of 99.9 pure percentage was used as silica. Kaolin was also commercially available with controlled composition. The chemical composition of clay, kaolin and blast furnace slag (BFS) are summarized in Table 1.

We designed two batches of different ceramic compound mixes, utilizing a common industrial tri-axial formulation [7]. The materials in each vertex of the triangle were clay, quartz and kaolin. The variation of the amounts of each compound went from 10% to 50% in order to reach 100% of the mixture. We selected 14 points as shown in Figure 1. The sintering of the samples was conducted using an electric laboratory oven at 1100° C during six hours. This first batch was named as the reference formulation in order to observe fresh and sintered properties (plasticity, dry and sintered shrinkage, and sintered porosity), of typical industrial formulations. On the other hand, in the second batch's formulation, we completely replace the kaolin by slag and selected the same 14 points previously defined to conduct a comparative analysis.

Each sample point had a total weight of dry material of 100 gr. All the dry materials were manually mixed for a period of five minutes using a ceramic mortar. After this mixing period, around 50 wt. % of water was added in order to homogenize the materials. After the addition of water, the saturated paste was placed over gypsum plaster clapboard in order to reduce excess moisture.

Table 1. Chemical composition ofclay, kaolin and blast furnace slag.

Oxide content in different materials (%)

Kaolin Blast Furnace Slag Lerma Clay

SiO2 45.7 18.4 58.2

Al2O3 37.4 6.8 26.2

Fe2O3 0.8 2.4 4.8

TiO2 0.4 0.1 1.2

P2O5 0.2 0.1 ----

CaO 0.2 38.6 0.6

MgO 0.1 6.5 0.8

Na2O 0.1 ---- 0.2

K2O 0.3 ---- 1.6

We measured plasticity in accordance with the plasticity scale proposed by Singer where exceptional, good, medium, poor and null are the values that this variable can take [7].

LERMA CLAY 100%

Fig. 1. Tri-axial diagram utilized for the ceramic compound mix design. Clay, quartz and kaolin or slag are placed in each vertex.

After measuring plasticity, three tiles of 120x10x5 mm were prepared for each of the 28 analyzed points. A line of 100 mm length was traced over the upper face of tile (120x10 mm) in order to assess the dry and sintered shrinkage as shown in Figure 2. The dry shrinkage was measured after the tiles were placed into the stove at 40° C for one day in order to eliminate humidity. The length decrease of the 100 mm line expressed as a percentage of the original line size is the dry shrinkage. Sintered shrinkage is the reduction of the line length also expressed as a percentage of the original line size after sintering process. The reported values of shrinkage are the 3 tiles average.

Fig. 2. (a) Utilized Molds to form the clay tiles. (b) The complete batch built by 14 samples as defined in the tri-axial diagram.

The sintered porosity was determined by Hald's procedure [8]. After sintered, the samples are oven dried at 110°C for 12 hours. Afterwards they are dry weighted, and then the samples are immersed in boiling water for a period of two hours. The saturated samples are newly weighted and the porosity is the percentage of the weight increase after water saturation.

3. Results and discussion

Table 2 shows plasticity values, the dry & sintered shrinkage and also the sintered porosity average values for each point of the two different characterized batches. Figure 3 shows a picture of each batch after the sintering process.

Table 2. Plasticity, dry & sintered shrinkage and sintered porosity measured values.

Control Batch Slag Batch

Sample Code Plasticity Shrinkage (%) Dry Sintered Porosity (%) Sample Code Plasticity Shrinkage (%) Dry Sintered Porosity (%)

C1 Exceptional 7.0 13.0 10.96 S1 Good 5.0 9.0 24.14

C2 Exceptional 6-0 11.0 12.70 S2 Good 5.0 9.0 20.22

C3 Exceptional 6.0 13.0 9.44 S3 Good 3.0 6.0 28.38

C4 Exceptional 5.7 11.0 13.51 S4 Medium 4.0 7.0 24.86

C5 Exceptional 5.0 9.0 13.64 S5 Medium 4.0 7.0 23.91

C6 Exceptional 6.0 11.0 13.01 S6 Poor 3.0 5.0 28.57

C7 Exceptional 6.0 10.0 11.81 S7 Poor 3.0 5.0 27.13

C8 Good 5.0 8.0 14.97 S8 Poor 3.0 5.0 26.46

C9 Good 5.3 5.3 16.92 S9 Null 3.3 5.0 24.48

C10 Exceptional 5.0 11.0 12.36 S10 Null 2.0 4.0 31.87

C11 Exceptional 5.0 10.0 14.59 S11 Null 2.0 5.0 30.56

C12 Good 5.0 8.0 15.66 S12 Null 2.0 4.0 28.19

C13 Medium 5.0 7.0 16.43 S13 Null 2.0 3.0 28.72

C14 Medium 4.7 6.0 17.21 S14 Null 2.0 4.0 26.42

Note: In the sample code, the number after each letter, denotes each of the selected points of the tri-axial diagram (Fig 1), e. g, in sample C7, C denotes that this sample is from the control batch, 7 denotes point 7 as defined in the tri-axial diagram; it contains 50% clay, 20% quartz and 30% kaolin. Letter S denotes total replacement of kaolin by blast furnace si

As can be observed from data in Table 2, the control batch showed the better values of plasticity; most of the 14 samples where catalogued from exceptional to medium, this is the expected behavior required to accurately form different shapes of clay for industrial purposes when the ceramic compound mix is designed utilizing the tri-axial diagram methodology with the materials reported herein (clay, quartz and kaolin), in such a case kaolin provides plasticity to the mix [7, 9]. On the other hand, the slag batch showed less favorable plasticity behavior. As shown in Table 1, the slag contents almost 40% of Calcium Oxide (CaO). The CaO reacts in the presence of water to produce calcium hydroxide Ca(OH)2. The calcium hydroxide is a sort of cementitious material that tends to harden and to produce stiffness as the hydration process is being produced. This natural behavior of Ca(OH)2 produces the loss of plasticity reported in Table 2. In order to attain to an adequate plasticity, it was necessary to add larger amounts of water to the slag batch than the 50 wt. % supplied to control batch.

Fig. 3. Sintered samples. (a) Control batch. (b) Slag batch.

On the other hand, the slag batch displayed less dry and sintered shrinkage than the one observed in our control batch. This behavior can be explained by emerge of calcium hydroxide due to presence of Calcium Oxide contented in the slag. The stiffening provided by the Ca(OH)2 leads to a better mechanical behavior previously to sintering process, producing less reduction of the original length when water evaporates.

Finally, regarding the porosity, the slag batch showed higher values than the control batch. Again this behavior can be related to the greater amount of water required to achieve an adequate plasticity. When water is evaporated from the paste before the sintering process, the space filled by it is occupied by the atmospheric air. Furthermore, part of the additional water supplied to the slag mixture was chemically joined to the CaO to form calcium hydroxide. If water is removed from Ca(OH)2, then calcium oxide is retrieved, this chemical change is produced during the sintering process and, the water joined to calcium hydroxide is removed by evaporation at 1100° C, leading to more space previously occupied by water now filled with air. It is worth to note that to the naked eye, it is notable the presence of higher porosity in the slag batch when compared with the control samples as appreciate in Figure 3.

It is necessary to conduct further characterization of materials, as well as the precursors (clay and slag) and the sintered ceramics concerning with a better understanding of the expected chemical reactions and the formation of minerals due to the combination of the products used in this research. It is necessary to explore other alternatives to

remove the calcium oxide excess and monitor the yielding sintered ceramics and their properties; the alternative replacement product must have a similar chemical composition as kaolin (the slag without CaO).

4. Conclusions

The total replacement of kaolin in the formulation of clay ceramic compound mix was conducted by using a blast furnace slag with high content of silica and calcium oxide.

The presence of calcium oxide in the slag produced a larger amount of water required for the preparation of the ceramic compound mix, leading to a loss of plasticity and the increase of the sintered porosity; this could be due to the formation of calcium hydroxide.

Further characterization of materials is required for a better understanding of the expected chemical reactions and the formation of minerals due to the combination of the products used in this research.

It is necessary to explore some alternatives to remove calcium oxide excess and then to observe the properties of the materials obtained using the same blast furnace slag free of CaO contamination.

Acknowledgements

This research was partially supported by the Secretaría de Investigación y Estudios Avanzados of the Universidad Autónoma del Estado de México by grant numbers 3752/2014/CID & 3814/2014/CIA and by CONACyT under grant number 133229.

References

[1] CEN, Standard EN197. Cement - Part 1: Composition, specifications and conformity criteria for common cements Brussels: European Commitee for Standarization, 2008.

[2] M. S. Imbabi, C. Carrigan and S. McKenna, "Trends and developments in green cement and concrete technology," International Journal of Sustainable Built Environment, vol. 1, p. 194-216, 2012.

[3] A. Hasanbeigi, L. Price and E. Lin, "Emerging energy-efficiency and CO2 emission-reductiontechnologies for cement and concrete production: A technical review," Renewable and Sustainable Energy Reviews, vol. 16, p. 6220 -6238, 2012.

[4] J. G. Osuna-Alarcón, R. A Pérez-Guzmán and E. M. Múzquiz-Ramos, "Reciclado de escoria de alto horno para la producción de loseta vitrocerámica," Acta Química Mexicana, vol. 1, no. 2, pp. 1-14, 2009.

[5] K. Dana and S. Das, "Partial subtitution of feldspart by B.F. slag in triaxal porcelain: phase and microstructural evolution," Journal of the European Ceramic Society, vol. 24, pp. 3833-3839, 2004.

[6] E. Karamanova, G. AvdeeV and A Karamanov, "Ceramics from blast furnace slag, kaolin and quartz," Journal of the European Ceramic Society, vol. 31, pp. 989-998, 2011.

[7] F. Singer, Cerámica Industrial. Enciclopedia de la Química Industrial vol. 9, Bilbao: URMO, 1979.

[8] P. Hald, Técnica de la Cerámica, Barcelona Ediciones Omega, 1977.

[9] D. W. Richerson, Modern Ceramics Engineering, New York: Marsel Deker, 1992.