scholarly journals Waste to Wealth Strategy: Preparation and Properties of Lightweight Al2O3-SiO2-Rich Castables Using Aluminum Dross Waste

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7803
Author(s):  
Nan Su ◽  
Zishen Li ◽  
Youdong Ding ◽  
Hongliang Yang ◽  
Jingzhou Zhang ◽  
...  

Aluminum dross is a well-known industrial waste generated in the aluminium industry, and its recycling and reuse is still a worldwide issue. Herein, aluminum dross waste (ADW) was recycled to progressively replace the aggregate fraction of clay at 70, 75, 80, 85, and 90 wt% for the fabrication of Al2O3-SiO2-rich porous castable refractories. Their physical properties and mechanical behavior were assessed by the measurement of linear shrinkage rate, bulk density, apparent porosity, cold crushing strength, and thermal conductivity. The microstructure and phase evolutions were analyzed via scanning electron microscopy (SEM) and X-ray diffraction (XRD). The incorporation of 85 wt% of ADW allowed the development of a waste-containing conventional refractory castable with improved properties as compared to those of the other samples. The sustainable refractory castable exhibited decent thermal conductivity and physical and mechanical characteristics, and is suitable for application as reheating furnace lining. It is a “green” practice to partially replace the traditional raw materials with industrial waste in the manufacture of conventional refractory castables and provides environmental and economic benefits.

2020 ◽  
Vol 17 (2) ◽  
pp. 113-119
Author(s):  
H.E. Mgbemere ◽  
E.O. Obidiegwu ◽  
A.U. Ubong

In this research, kaolin, ball clay, sawdust and rice husk were used to produce insulation bricks through the solid state synthesis method. Two temperatures, 1100oC and 1200oC were used to sinter the green samples. X-ray fluorescence, scanning electron microscopy, compressive strength tests etc. were used to analyse the properties of the produced bricks. Chemical composition analysis on the starting raw materials showed that SiO2 and Al2O3 were the major constituents while Fe2O3, Na2O, K2O and TiO2 were the minor constituents. As the amounts of kaolin used in preparing the samples decrease, the bulk density, modulus of rupture and cold crushing strength of the bricks decreases while the water absorption capacity, linear shrinkage increases. The thermal analysis showed that on heating the samples, the reactions were mainly exothermic with between 8 to 10 mW/mg of heat released. The morphology of the samples showed that the pores began to collapse when the amount of kaolin present is below 70 wt. %. Sintering the samples at 1100oC and 1200oC led to slightly different values in the results and is therefore very significant. Keywords: Insulation bricks, Kaolin, sawdust, rice husk, temperature effects


2016 ◽  
Vol 697 ◽  
pp. 547-550 ◽  
Author(s):  
Meng Fei Wu ◽  
Yuan Bing Li ◽  
Shu Jing Li ◽  
Ya Wei Li ◽  
Shao Bai Sang

In this paper, high-purity porous calcium hexaluminate materials were prepared with α-alumina, nano-meter calcium carbonate and ρ-alumina as raw materials. The properties of the prepared porous materials, such as bulk density, true density, thermal conductivity, and cold crushing strength, were investigated. The increase in sintering temperature led to the increase of true density. Bulk density and cold crushing strength of the specimen fired at 1500°C had the lowest values. As ρ-alumina content increased, bulk density, true density, and cold crushing strength had no obvious changes, but the thermal conductivity decreased at first and then increased. The calcium hexaluminate formation was intense from 1450°C to 1500°C and finished at 1500°C. Above 1500°C, the main phase of specimens was calcium hexaluminate (CA6). And CA6 grains were regular hexagonal plates morphology and widely spread after firing at 1550°C.


Respuestas ◽  
2018 ◽  
Vol 23 (1) ◽  
pp. 27 ◽  
Author(s):  
Jorge Sanchez-Molina ◽  
Diana Carolina Alvarez-Rozo ◽  
John Fredy Gelves-Díaz

ResumenLa industria cerámica representa un sector representativo para la economía del Norte de Santander. A pesar del reconocimiento de la calidad de los productos fabricados a nivel nacional e internacional, el desarrollo del sector aún se encuentra en fase de consolidación si se compara con los grandes referentes del mundo, entre estos, la industria cerámica Española e Italiana. En la búsqueda de alternativas que permitan entrar en esta dinámica global, el equipo de investigación realizó algunas actividades encaminadas a aplicar el concepto de la economía circular (reutilización de residuos a los sistemas de producción) al proceso cerámico regional. En este caso particular se ha propuesto la reutilización del cisco de café (residuo de agroindustria regional) como sustituto del material arcilloso en la fabricación de materiales cerámicos de construcción. El trabajo experimental se desarrolló a nivel de laboratorio, usando la extrusión como técnica de conformado. Las materias primas fueron caracterizadas mediante fluorescencia y difracción de rayos X (FRX/DRX), así como por análisis térmico (TG/DSC); las propiedades tecnológicas del cerámico evaluadas fueron: la contracción lineal de secado/cocción, porcentaje de absorción de agua, resistencia mecánica a la flexión y resistencia a la abrasión profunda. Al material de mejor comportamiento físico cerámico le fue evaluada la conductividad térmica mediante un método transitorio de flujo de calor. Los resultados obtenidos evidencian el potencial del cisco para reducir la conductividad térmica del material y el aporte calórico al sistema. La utilización del cisco de café permite obtener cerámicos para uso como revestimientos y pavimento de tipo residencial.Palabras clave: Caracterización, cisco de café, economía circular, materiales cerámicos.AbtractThe ceramic industry is a representative sector for the economy of Norte de Santander (Colombia). Despite the recognition of the quality of the products manufactured nationally and internationally, the development of the sector is still in the consolidation phase if it is compared with the major references in the world, including the Spanish and Italian ceramic industry. In the search for   alternatives that allow entering this global dynamic of being recognized, the work team has carried out some activities aimed at applying the concept of the circular economy (reuse of waste to production systems) to the regional ceramic process. In this   particular case, the reuse of coffee husk (waste from regional agro-industry) as a substitute for clay material in the manufacture of ceramic construction materials has been proposed. The experimental work was developed at the laboratory level, using extrusion as a forming technique. The raw materials were characterized by fluorescence and X-ray diffraction (XRF / XRD), as well as by thermal analysis (TG / DSC). The technological properties of the ceramic evaluated were the linear shrinkage of drying / firing, percentage of water absorption, mechanical resistance to bending and resistance to deep abrasion. To the material with the best ceramic physical behavior, the thermal conductivity was evaluated by means of a transient heat flow method. The results obtained show the potential of the coffee husk to reduce the thermal conductivity of the material and the caloric contribution to the system. The use of coffee husk allows to obtain ceramics for use as coatings and residential type pavement.Keywords: Characterization, coffee husk, circular economy, ceramic materialsResumoA indústria cerâmica representa um setor representativo para a economia do Norte de Santander. Apesar do reconhecimento da qualidade dos produtos fabricados nos níveis nacionais e internacionais, o desenvolvimento do setor ainda está em fase de consolidação, quando comparado com as grandes figuras do mundo, entre eles, a indústria cerâmica espanhol e italiano. Na busca de alternativas que permitissem entrar nessa dinâmica global, a equipe de pesquisa realizou algumas atividades voltadas à aplicação do conceito de economia circular (reutilização de resíduos aos sistemas produtivos) ao processo cerâmico regional. Neste caso particular, tem sido proposto o reuso do café cisco (resíduo da agroindústria regional) como substituto do material argiloso na fabricação de materiais cerâmicos de construção. O trabalho experimental foi desenvolvido em nível de laboratório, usando a extrusão como técnica de formação. As matérias-primas foram caracterizadas por fluorescência e difração de raios-X (FRX / DRX), bem como por análise térmica (TG / DSC); As propriedades tecnológicas das cerâmicas avaliadas foram: retração linear de secagem / cozimento, porcentagem de absorção de água, resistência mecânica à flexão e resistência à abrasão profunda. Para o material com melhor comportamento físico cerâmico, a condutividade térmica foi avaliada por meio de um método de fluxo de calor transiente. Os resultados obtidos mostram o potencial do cisco para reduzir a condutividade térmica do material e a contribuição calórica para o sistema. O uso do café cisco permite obter cerâmicas para uso como revestimentos e pavimentos residenciais.Palabras Chave: Caracterização, cisco de café, economia circular, materiais cerâmicos.


2010 ◽  
Vol 105-106 ◽  
pp. 9-11
Author(s):  
Jian Er Zhou ◽  
Xue Bing Hu ◽  
Shuang Hua Wang ◽  
Yong Qing Wang ◽  
Xiao Zhen Zhang

Using aluminum chloride, aluminite powders and butyl titanate as raw materials, alumina- aluminum titanate fiber was prepared by sol-gel method at 1200°C. The influences of the holding time on the aspect ratio, the bulk density, the thermal conductivity coefficient and the heating linear shrinkage of the fiber were studied systemically. The results show that the holding time has an important effect on the properties of the fiber. With the increase of the holding time from 0 h to 3 h, the aspect ratio of the fiber decreases from 870 to 210 and the bulk density of the fiber adds from 352 Kg•m-3 to 432 Kg•m-3. Furthermore, the thermal conductivity coefficient of the fiber keeps rising from 0.162 W•m-1•K-1 to 0.199 W•m-1•K-1 and the heating linear shrinkage of the fiber decreases from 2% to 1.82%.


2018 ◽  
Vol 760 ◽  
pp. 132-138
Author(s):  
Lenka Nevřivová

In this research, the impact of firing temperature and MgO addition on mechanical and physical properties of self–compacting no-cement castables were investigated. For this propose up to 3.3 wt % of MgO was added to the corundum castable compositions and the specimens were fired at 600 °C, 800 °C, 1000°C, 1200°C and 1500°C. The mixtures were made so that the consistency of each one was the same. There were only minimal differences in the mixtures water content. The mineral composition of the input raw materials for manufacturing of the refractory castables was determined. The physical and mechanical properties of castable compositions such as self-flow values, bulk density, apparent porosity, cold crushing strength and flexural strength were examined. Also, the X-ray diffraction (XRD) and scanning electron microscopy (SEM/EDX) techniques were used for detection the ceramic phase formation. The corrosion resistance was determined by means of the crucible test according to ČSN P CEN/TS 15418 (726022) Method of test for dense refractory products – Guidelines for testing the corrosion resistance of refractories caused by liquids. The study follows up on research, the results of which were published last year [1], but the study is focused to self-compacting refractory castable.


2020 ◽  
pp. 180-191
Author(s):  
A. O. Aluko ◽  
C. O. Ikubuwaje

The influence of the weight of grog on some refractory properties of raw Abusoro clay samples found in Abusoro Village, Ondo State, Nigeria was evaluated. These samples were presented for refractory tests (apparent porosity, linear shrinkage, refractoriness, bulk density and cold crushing strength). The weights of the grog were varied from 20-40 wt. % in the blend. The chemical and microstructural examinations of the untreated alumino-silicate Abusoro clay samples indicated that they are abundant in silica, SiO2 (62.74wt. %) and alumina, Al2O3 (31.42wt. %). Other minor compounds found are Fe2O3 (1.43%), K2O (0.30%) with no trace amounts of MgO (0.00); therefore, they are regarded as alumino-silicate. Particular observation is made on MgO with zero amounts and the total of K2O + Na2O + MgO which are less than 2% in the clay samples. These results signify that the clay possesses high viability for manufacturing of refractory bricks, pulp and paper, ceramics, fertilizers, paint and cement. The performance evaluations of the refractory bricks measured indicated acceptable and satisfactory results vis-à-vis standard refractory properties for refractory fireclay bricks. However, the apparent porosity (43.2%) and CCS (21.21MPa) obtained for Abusoro clay sample at 30% weight of grog may as well be suitable for insulating refractory applications. The high apparent porosity could be an indication of high content of silicon oxide in the raw clay.


2021 ◽  
pp. 002199832110316
Author(s):  
Nuno Gama ◽  
B Godinho ◽  
Ana Barros-Timmons ◽  
Artur Ferreira

In this study polyurethane (PU) residues were mixed with residues of textile fibers (cotton, wool and synthetic fibers up to 70 wt/wt) to produce 100% recycled composites. In addition, the effect of the type of fiber on the performance of the ensuing composites was evaluated. The presence of fibers showed similar effect on the density, reducing the density in the 5.5-9.0% range. In a similar manner, the addition of fillers decreased their thermal conductivity. The 70 wt/wt wool composite presented 38.1% lower thermal conductivity when compared to the neat matrix, a reduction that was similar for the other type of fibers. Moreover, the presence of fillers yields stiffer materials, especially in the case of the Wool based composites, which with 70 wt/wt of filler content increased the tensile modulus of the ensuing material 3.4 times. This was attributed to the aspect ratio and stiffness of this type of fiber. Finally, the high-water absorption and lower thermal stability observed, especially in the case of the natural fibers, was associated with the hydrophilic nature of fibers and porosity of composites. Overall, the results suggest that these textile-based composites are suitable for construction and automotive applications, with the advantage of being produced from 100% recycled raw-materials, without compromised performance.


2021 ◽  
Vol 11 (8) ◽  
pp. 3545
Author(s):  
Fernanda Andreola ◽  
Isabella Lancellotti ◽  
Paolo Pozzi ◽  
Luisa Barbieri

This research reports results of eco-compatible building material obtained without natural raw materials. A mixture of sludge from a ceramic wastewater treatment plant and glass cullet from the urban collection was used to obtain high sintered products suitable to be used as covering floor/wall tiles in buildings. The fired samples were tested by water absorption, linear shrinkage, apparent density, and mechanical and chemical properties. Satisfactory results were achieved from densification properties and SEM/XRD analyses showed a compact polycrystalline microstructure with albite and wollastonite embedded in the glassy phase, similar to other commercial glass-ceramics. Besides, the products were obtained with a reduction of 200 °C with respect to the firing temperatures of commercial ones. Additionally, the realized materials were undergone to leaching test following Italian regulation to evaluate the mobility of hazardous ions present into the sludge. The data obtained verified that after thermal treatment the heavy metals were immobilized into the ceramic matrix without further environmental impact for the product use. The results of the research confirm that this valorization of matter using only residues produces glass ceramics high sintered suitable to be used as tile with technological properties similar or higher than commercial ones.


2021 ◽  
Vol 320 ◽  
pp. 181-185
Author(s):  
Elvija Namsone ◽  
Genadijs Sahmenko ◽  
Irina Shvetsova ◽  
Aleksandrs Korjakins

Because of low calcination temperature, magnesia binders are attributed as low-CO2 emission materials that can benefit the environment by reducing the energy consumption of building sector. Portland cement in different areas of construction can be replaced by magnesia binder which do not require autoclave treatment for hardening, it has low thermal conductivity and high strength properties. Magnesium-based materials are characterized by decorativeness and ecological compatibility.The experimental part of this research is based on the preparation of magnesia binders by adding raw materials and calcinated products and caustic magnesia. The aim of this study was to obtain low-CO2 emission and eco-friendly material using local dolomite waste materials, comparing physical, mechanical, thermal properties of magnesium binders.


2013 ◽  
Vol 2013 ◽  
pp. 1-4
Author(s):  
Mihail Doynov ◽  
Tsvetan Dimitrov ◽  
Maria Kokkori

The synthesis of arsenic-free ceramics from industrial waste is studied. Samples of waste containing siliceous material passed the exploitation leap-guard layer shift reactor whose main oxide is -Al2O3and, with the addition of natural raw materials and pure oxide, arsenic-free ceramics were synthesized with thermal and electrical properties related to the main phase of spinel group minerals; solid solutions were also formed in the process of synthesis. Insulating properties were established by successive heating and cooling of the specimen for six cycles. Electrical insulating properties were established by the method of resistance to arcing. The relative density was determined by hydrostatic method and diffusion lines of molecules at the main phase were characterized by X-ray diffraction analysis. The experimental procedures followed in this study allowed mixing on a molecular level due to the small dimensions of the crystallite which in turn explains the relatively high density.


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