Use of Kaolin Processing Waste for the Production of Mullite Bodies

Brasileiro, Maria Isabel; Menezes, Romualdo Rodrigues; Farias, Mainara; Lira, Hélio Lucena; Neves, G. A.; Santana, Lisiane Navarro de Lima

doi:10.4028/www.scientific.net/msf.591-593.799

Cited by 10 publications

(9 citation statements)

References 16 publications

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“…This result is in connection with the ceramic properties of the sample presented in Figures 7-9 concerning the firing behaviour with the vitrification features (see Section 3.5). Then, ceramic bodies with high relative proportion of crystalline mullite and minor of quartz, besides vitreous phase, can be obtained by firing at 1300-1350 • C. In general, these thermal features are in agreement with previous results reported in studies on kaolinitic clays [19,34,39,56,60].…”

Section: Development and Evolution Of Crystalline Phases By Thermal T...supporting

confidence: 89%

“…Several important industries use this kind of refractories, for instance iron and steel, cement, catalysts, petrochemicals, glass and many other advanced functional applications [20][21][22][23][24][25][26][27][28][29][30][31][32]. Thus, it is very important and a real problem the valorization of mining residues by the production of mullite-based ceramic materials [32][33][34][35][36][37][38][39][40][41]. This investigation is a contribution for this purpose.…”

Section: Introductionmentioning

confidence: 99%

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Study of a Waste Kaolin as Raw Material for Mullite Ceramics and Mullite Refractories by Reaction Sintering

et al. 2022

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A deposit of raw kaolin, located in West Andalusia (Spain), was studied in this work using a representative sample. The methods of characterization were X-ray diffraction (XRD), X-ray fluorescence (XRF), particle size analysis by sieving and sedimentation, and thermal analysis. The ceramic properties were determined. A sample of commercial kaolin from Burela (Lugo, Spain), with applications in the ceramic industry, was used in some determinations for comparison purposes. The kaolin deposit has been produced by alteration of feldspar-rich rocks. This raw kaolin was applied as an additive in local manufactures of ceramics and refractories. However, there is not previous studies concerning its characteristics and firing properties. Thus, the meaning of this investigation was to conduct a scientific study on this subject and to evaluate the possibilities of application. The raw kaolin was washed for the beneficiation of the rock using water to increase the kaolinite content of the resultant material. The results indicated that the kaolinite content of the raw material was 20 wt % as determined by XRD, showing ~23 wt % of particles lower than 63 µm. The kaolinite content of the fraction lower than 63 µm was 50 wt %. Thus, an improvement of the kaolinite content of this raw kaolin was produced by wet separation. However, the kaolin was considered as a waste kaolin, with microcline, muscovite and quartz identified by XRD. Thermal analyses by Thermo-Dilatometry (TD), Differential Thermal Analysis (DTA) and Thermo-Gravimetry (TG) allowed observe kaolinite thermal decomposition, quartz phase transition and sintering effects. Pressed samples of this raw kaolin, the fraction lower than 63 µm obtained by water washing and the raw kaolin ground using a hammer mill were fired at several temperatures in the range 1000–1500 °C for 2 h. The ceramic properties of all these samples were determined and compared. The results showed the progressive linear firing shrinkage by sintering in these samples, with a maximum value of ~9% in the fraction lower than 63 µm. In general, water absorption capacity of the fired samples showed a decrease from ~18–20% at 1050 °C up to almost zero after firing at 1300 °C, followed by an increase of the experimental values. The open porosity was almost zero after firing at 1350 °C for 2 h and the bulk density reached a maximum value of 2.40 g/cm3 as observed in the ground raw kaolin sample. The XRD examination of fired samples indicated that they are composed by mullite, from kaolinite thermal decomposition, and quartz, present in the raw sample, as main crystalline phases besides a vitreous phase. Fully-densified or vitrified materials were obtained by firing at 1300–1350 °C for 2 h. In a second step of this research, it was examined the promising application of the previous study to increase the amount of mullite by incorporation of alumina (α-alumina) to this kaolin sample. Firing of mixtures, prepared using this kaolin and α-alumina under wet processing conditions, produced the increase of mullite in relative proportion by reaction sintering at temperatures higher than 1500 °C for 2 h. Consequently, a mullite refractory can be prepared using this kaolin. This processing of high-alumina refractories is favoured by a previous size separation, which increases the kaolinite content, or better a grinding treatment of the raw kaolin.

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Section: Development and Evolution Of Crystalline Phases By Thermal T...supporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Study of a Waste Kaolin as Raw Material for Mullite Ceramics and Mullite Refractories by Reaction Sintering

et al. 2022

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“…The kaolin waste generally discarded in the open air causes significant environmental problems; affecting fauna, flora and people's health. Numerous studies have been dedicated to the recycling of kaolin processing waste aimed at the production of bricks, tiles and ceramic coatings [12][13][14][15][16]. However, recycling and reuse of wastes should not only be seen from an environmental point of view but also in terms of economic viability.…”

Section: Introductionmentioning

confidence: 99%

Preparation of mullite based ceramics from clay–kaolin waste mixtures

Alves

Silva

Campos

et al. 2016

Ceramics International

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“…Tables 15-17 list the chemical composition of primary kaolin industry waste, processing parameters and technological properties of the ceramic materials developed. Brasileiro et al [133,134] reported the use of the residue from the primary kaolin industry as alternative raw material for the production of mullite ceramics. The kaolin residue is mainly composed of SiO ).…”

Section: Kaolin Processing Wastementioning

confidence: 99%

Mullite-Based Ceramics from Mining Waste: A Review

et al. 2021

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Mullite (3Al2O3·2SiO2) is an aluminosilicate characterized by excellent physical properties, which makes it an important ceramic material. In this way, ceramics based on mullite find applications in different technological fields as refractory material (metallurgy, glass, ceramics, etc.), matrix in composite materials for high temperature applications, substrate in multilayer packaging, protective coatings, components of turbine engines, windows transparent to infrared radiation, etc. However, mullite is scarce in nature so it has to be manufactured through different synthesis methods, such as sintering, melting-crystallization or through a sol-gel route. Commonly, mullite is fabricated from pure technical grade raw materials, making the manufacturing process expensive. An alternative to lowering the cost is the use of mining waste as silica (SiO2) and alumina (Al2O3) feedstock, which are the necessary chemical compounds required to manufacture mullite ceramics. In addition to the economic benefits, the use of mining waste brings out environmental benefits as it prevents the over-exploitation of natural resources and reduces the volume of mining waste that needs to be managed. This article reviews the scientific studies carried out in order to use waste (steriles and tailings) generated in mining activities for the manufacture of clay-based ceramic materials containing mullite as a main crystalline phase.

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Use of Kaolin Processing Waste for the Production of Mullite Bodies

Cited by 10 publications

References 16 publications

Study of a Waste Kaolin as Raw Material for Mullite Ceramics and Mullite Refractories by Reaction Sintering

Study of a Waste Kaolin as Raw Material for Mullite Ceramics and Mullite Refractories by Reaction Sintering

Preparation of mullite based ceramics from clay–kaolin waste mixtures

Mullite-Based Ceramics from Mining Waste: A Review

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