Stoneware Body Research Articles

Examining the properties, behaviour in firing and potential application of coal mine overburden for stoneware ceramics

Purpose. A binary mixture of a ceramic body was studied, incorporating overburden from a coal mine site in Bontang, East Kalimantan, Indonesia. This overburden material has been tested for the manufacture of stone-ceramic body. Methods. The initial characterization of overburden materials includes testing the chemical composition by XRF analysis and mineral content by XRD analysis on raw materials and overburden exposed to high temperature. The composition of ceramic specimens is a mixture of 85% overburden material and 15% fine sand. Firing temperatures in the range of 900-1100°C were applied to the ceramic body specimen. Then, ceramic properties, such as physical color, plasticity, shrinkage, water absorption and density were analyzed. Findings. The results show that the ceramic specimen experiences densification when exposed to high temperature in this range, which in turn contributes to low water absorption and high flexural strength. This ultimately results in low water absorption below 1.0% at 1100°C, which is favorable for stoneware type of ceramics. The mechanical properties of specimen at 1000°C is in accordance with stoneware body standard. In addition to this, it is believed to be more energy efficient, since the low firing temperature is sufficient to achieve the stoneware specification. Originality. The binary clay-based ceramic have been tested using coal mine overburden and river sand with a high Fe2O3 content. Together with the presence of alkali oxides and calcium in the raw materials, this can potentially reduce the use of fluxing agent. A comprehensive study has been conducted on the characteristics, firing effect and application of stoneware. Practical implications. Some ceramic prototypes from this result were also made using a rotary technique and heated in this temperature range. Since overburden is generally considered to be backfill material, the selective clay material application for ceramics can provide the potential to stimulate local product innovation by utilizing easily available overburden materials.

Fabricating Ceramic Scaffolding Nest through the addition of Calcium Carbonate (CaCO₃) in Ceramic Stoneware Body

Edible bird nest (EBN) is based from swiftlet's saliva and it is widely consumed as a health food due to its high beneficial effects to human health and has been considered to be one of the most precious food items by the Chinese for thousands of years. The role of a scaffolding nest is to guide the young swiftlet to build a typical form of the edible bird nest that will increase its commercial values. However, the price of edible bird nests decreased due to various shapes and sizes of EBN in the market. This study will design standard scaffolding nests followed by MS 2334:2011 and introduce the Calcium Carbonate as the main material and associate it with the stoneware body as the binder to create a natural environment to swiftlets.

Kinetics of the transformations occurring during the firing process of an industrial spray-dried porcelain stoneware body

Pressed compacts of an industrial spray-dried porcelain stoneware powder, consisting mainly of albite, quartz, kaolinite, and illite, were thermally treated at different temperatures and times. Fired test piece bulk density and water absorption, in addition to phase content (using X-ray diffraction (XRD) data and Rietveld refinements) and microstructure (using scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM–EDS)), were determined. The isothermal kinetics of densification, mullite precipitation, and feldspar and quartz dissolution were obtained. The evolution of the mullite, quartz, feldspar, and vitreous phase mass percentages with the dissolved feldspar fraction was independent of thermal treatment. The evolution of water absorption, linear shrinkage, and bulk density with vitreous phase content was also independent of thermal treatment. Water absorption decreased linearly as vitreous phase content increased, until it cancelled out at a vitreous phase content of 66% by weight.

The Utilization of Volcanic Ash in Medium Fired Stoneware Ceramic Body

The aims of this research are to develop a medium fired stoneware body (1150 o C-1250 o C) as well as a prototype of glazed ceramic products based on several local clays using volcanic ash. The developed clay comes from Sukabumi, Singkawang, Bojonegoro and Malang. Research includes analysis of raw materials, development of stoneware ceramic bodies, testing of physical properties of ceramic bodies, determination of optimum ceramic bodies and development of prototype products. Raw material analysis consists of mineral analysis using XRD and Atomic Absorption Spectroscopy (AAS). Ceramic body development was carried out by the line blend method followed by testing plasticity, shrinkage, porosity and fracture strength. Prototype product development was carried out on optimum ceramic bodies composition. The results showed volcanic ash can be used to develop local clay-based ceramic stoneware bodies from Sukabumi, Bojonegoro and Malang which optimum ceramic bodies coded as Sb-2, Sb-3, Sb-4, Sb-5, Bn-5, Ml-4 and Ml-5 with volcanic ash percentage of 10%-40%. In this research, the optimum composition for Singkawang clay has not yet been found. However, opaq, matt and celadon glazes that applied to the optimum ceramic body resulted good and decent prototype products

REFRACTORY CLAY RAW MATERIALS OF REPUBLIC OF BELARUS FOR PRODUCTION OF THE PORCELAIN TILE

The possibility of replacing imported refractory clays and kaolines, which are part of porcelain stoneware mix, with refractory clay materials of the Republic of Belarus, in particular quartz-pyrophyllite-kaolinite rock and kaolin of “Dedovka” and “Sitnitsa” deposits, was explored. Porcelainised stoneware body formulations of JSC “Keramin” (Minsk, Republic of Belarus) was taken as the basis. It was found that physico-chemical properties and operational characteristics of porcelain tiles comply with the requirements of EN 14411: 2014, when adding 2.5–15.0 wt.% quartz-pyrophyllite-kaolinite rock. Incorporation of quartz-pyrophyllite-kaolinite rock in percentage higher than 15.0 wt.% resulted in reduction in the total amount of the vitreous phase of porcelain stoneware, thus increasing water absorption, apparent porosity as well as reduces flexural strength and bulk density. The main crystalline phases in the synthesized materials were quartz and mullite. It was also revealed that imported kaolines could be completely replaced by kaolines of “Dedovka” and “Sitnitsa” deposits. In this, required physico-chemical properties and operational characteristics of porcelain tiles was maintained. SEM analysis revealed that specimens synthesized using considered kaolines show quite dense microstructures, with a high degree of vitrification. The gas phase in these materials was practically absent, the presence of only individual small irregular pores was found. XRD analysis indicated that the major phases were mullite, quartz, microcline and hematite. It was hematite that gives the obtained porcelain stoneware samples a dark gray color scheme. Thus, the use of domestic refractory clay raw materials provides import substitution and declining production costs.

Usage of marble wastes in traditional artistic stoneware clay body

Abstract Recycling of industrial wastes aids environmentally friendly production and has the advantage of lowering costs. Marble production generates large amounts of waste. Recycling of such wastes by incorporating them into ceramic industry is a practical solution for pollution problem. The aim of this work is to assess the possibility of the recycling of marble wastes in the production of stoneware clay bodies as a raw material for ceramic artwork production. Five different clay body mixes containing marble waste up to 27% were prepared and evaluated for firing color, water emission, morphology, microstructure, thermal expansion coefficient and thermal behavior. The results of the tests show that the utilization of marble waste in stoneware body is feasible for ceramic artwork production.

Ceramic porcelain stoneware production with Spanish clays purified by means of the removal of iron compounds and organic matter using physical methods

As the production of ceramic porcelain stoneware in Spain is totally conditioned by the importation of ball clays, because of the lack of adequate Spanish ball clays, this work has focused on the formulation of ceramic porcelain body from Spanish clays purified by means of physical removal processes. This method was applied to three Spanish clays containing common clay impurities of iron (hematite and siderite) and organic matter. Iron removal was carried out using the wet sieve method, the hydrocycloning method and the electromagnetic filtering method, obtaining a reduction in iron content of up to 80wt%, while the clay containing organic matter was treated thermally at 400°C for 30min so as to leave it almost completely purified. These treated clays, after being characterized (chemical and mineralogical composition, plasticity, organic carbon, thermal behaviour and colour), were used in the porcelain stoneware body composition instead of imported clays, the result being a composition capable of substituting the standard porcelain stoneware formulation in terms of sintering, morphology, colour, flexural strength and dilatometry.

Metal nanoparticles in contemporary potters’ master pieces: Lustre and red “pigeon blood” potteries as models to understand the ancient pottery

Reduction of metal precursors within the molten glaze is a rather complex route to obtain coloured glaze. “Sang de bœuf”, “pigeon blood” or “flammé” first discovered glazes by the Chinese potters of the Song Dynasty (10th c.) are produced by atmosphere controlled firing of copper-containing glaze on porcelain and stoneware body. Lustre pottery, an Abbasid potters’ innovation (9th c.), offers to the eyes of the connoisseur an iridescent reflection, which is only visible at specular position. For centuries connoisseurs’ interest in these objects has been continuous and the development of transmission electronic microscopy (TEM) associated with energy-dispersive X-ray spectroscopy (TEM-EDX) allows us an in depth study of the micro and nano-structure of these objects. A porcelain with red “pigeon blood” decor made by the late famous French-American potter Fance Franck, and lustre stonewares made by the French potter Eva Haudum, have been investigated by TEM-EDX and nanochemical analysis in order to better understand the key parameters controlling the microstructure and the colour of glazes. Although some authors assigned the red colour of pigeon-blood to Cu2O, our results clearly demonstrate that the colour only arises from Cu° nanoparticles. Phase separation of the glassy phase was observed close to the surface. Concerning the lustrewares, analysis confirmed that the alternating reducing and oxidising conditions during the firing lead well to the formation of metal-free/metal-rich alternate layers in the lustre decor.

Thermal analysis and vitrification behavior of slag containing porcelain stoneware body

Three porcelain stoneware compositions were formulated using common ceramic minerals and slag of metallurgical industries. Standard body was prepared by mixing 45 % kaolin, 40 % feldspar and 15 % quartz (VP 1), and other two contain blast furnace (BF) and basic oxygen furnace slag replacing 30 % of feldspar (VP 2 and VP 3, respectively). The physical changes, phase transformation and mass loss were measured by simultaneous thermo-gravimetric and differential thermal analysis up to 1150 °C. The endothermic peaks obtained in the range of 519–520.79 °C were due to the dehydroxylation of kaolin and α to β quartz transformation. The exothermic peaks in the range of 1000–1080 °C were attributed to mullite crystallization. The compacted samples were heated in the temperature range of 1150–1280 °C. It was found that addition of slag replacing part of feldspar brought early vitrification compared to standard body. It was also observed that BF slag containing vitrified body shows superior flexural strength (>80 MPa). X-ray diffraction pattern, field emission scanning electron microscopic studies and energy-dispersive X-ray analysis confirm the presence of quartz and mullite in VP 1 and anorthite and quartz crystals in VP 2 and VP 3.

Effects of technical factors on dimensional stability of porcelain stoneware body during sintering process: Isothermal kinetic study, Part II

The effect of technical factors on dimensional stability of porcelain stoneware bodies during the isothermal sintering was investigated by measuring linear shrinkage. Different milling times and forming pressures were considered in the preparation of specimens. The sintering process was isothermally carried out at different soaking times. It was observed that the presence of nepheline syenite in the composition negatively affects the dimensional stability range. In order to improve the dimensional stability of modified composition, the milling time should be increased up to 12h. It was found that the pressure drastically influences the thermal shrinkage and dimensional stability range. The increment in pressure is able to reduce the defects of microstructure. In the next step, a modified kinetic model was applied to analyze the shrinkage variation. The heterogonous diffusion of liquid phase into the pores was confirmed from the computation of a dimensionless factor and calculation of average rate constant.

Crystalline phases and physical properties of modified stoneware body with glaze sludge

Ceramic stoneware body has been modified with ceramic and glass industrial wastes by replacing 25–100% as flux in the formula. The effects of solid wastes added to the bodies were studied after firing in the temperature range 950–1280°C. The physical properties of linear shrinkage, bulk density, apparent porosity, water absorption and 3-point bending strength were determined. A composition which related to the general stoneware properties was found when using soda-lime cullet and glaze sludge. It had a firing range lowered to 1050–1100°C. SEM results demonstrated the sintered microstructure increased in density with increase in solid waste in the modified body. XRD results after firing showed the crystalline phases comprised of mullite, albite calcian and quartz. Thermal expansion was measured in the range 6.53–6.67×10−6K−1 at 30–500°C. The modified bodies were capable of forming prototype products by slip casting and jiggering.

Characterization of Low Firing Temperature Ceramic Glaze Using Phuket MSW and Soda Lime Cullet

The normal firing temperature of ceramic products is around 1200 °C. In order to reduce firing temperature, industrial wastes were utilized in ceramic glaze. Phuket municipal solid waste (MSW), soda lime cullet, and borax were used as raw materials for low firing temperature glazes. The glaze compositions were designed using a triaxial diagram. Stoneware ceramic body was glazed then fired at 1000 and 1150 °C for 15 minutes. Morphology and phase composition of glazes were analyzed by Scanning electron microscopy (SEM-EDS) and X-ray diffraction (XRD). Thermal expansion compatibility of Stoneware body and glazes were investigated using a dilatometer. Melting behaviour of selected glaze was analyzed by heating stage microscopy. Phuket MSW and Soda lime glass cullet can be used in high percentage as major raw materials for low firing temperature ceramic glaze that show good texture and vitrified at lower firing temperature without using any commercial ceramic frits. The firing temperature can be reduced up to 150 °C in this study.

Influence of CaO–ZrO 2–Al 2O 3–SiO 2 glass-ceramic frits on the technological properties of porcelain stoneware bodies

In the present work, the effect of the addition to a porcelain stoneware body of glass-ceramic frits belonging to the CaO–ZrO 2–Al 2O 3–SiO 2 (CZAS, containing 1, 3, 5, and 10 mol% of Al 2O 3) system as replacement of the “state of the art” frit belonging to CaO–ZrO 2–SiO 2 system (CZS) was evaluated. The firing process was performed in a furnace able to complete the thermal cycle in 50 min, in order to simulate the industrial process. Technological properties such as water absorption, firing shrinkage, flexural strength, and thermal expansion behaviour were measured. Aesthetical properties were also evaluated. X-ray diffraction and scanning electron microscopy studies were also carried out to analyse the microstructure and the phase compositions of the studied samples. It was found that the sample containing the CZAS frit with 5 mol% of Al 2O 3 shows, in general, the best combination of properties in term of mechanical, physical and aesthetical properties.

Study of mullite formation in porcelain stoneware applying isoconversional and IKP methods

Abstract The growth process of mullite in a porcelain stoneware body has been studied under isoconversional, isokinetic relationship and invariant kinetic parameters. Activation energy for mullite crystallisation of over 589–628 kJ mol −1 and a Ln A over 50–59 min −1 was obtained. The model was Johnson–Melh–Avrami with n = 1.5. The model chosen implies quick nucleation and subsequent one or three-dimensional growth. Isoconversional methods show an independent activation energy variation in mid range conversion degrees. Lower and higher conversion degrees show different reactions in mullite formation. Results obtained with the methods employed here are in agreement with a previous paper where the Kissinger non-isothermal method and Ligero et al. approximation were applied.

Kinetic model for isothermal sintering of porcelain stoneware body in presence of nepheline syenite

The effect of nepheline syenite on porosity–soaking time relationship of porcelain stoneware bodies has been studied using the experimentally measured total porosity. A new kinetic model was applied to quantify porosity as function of temperature and soaking time. In the first part of work, the effect of nepheline syenite was evaluated on the kinetic parameters and the porosity variations were found to be related to surface tension/viscosity ratio of melted phase which influences the minimum porosity of ceramic body. The kinetic analysis of data indicated that the optimum soaking time to achieve minimum porosity in ceramic body is controlled by amount of nepheline syenite and milling time. The validity of presented theory to predict the experimental results was substantiated by computing total porosity at other temperatures and soaking times. The proposed model can be used to describe the sintering process of ceramic bodies that are sintered by diffusing melted phase.

Malayaite Ceramic Pigments Prepared from Industrial Wastes: Formulation and Characterization

In this work chrome-tin red malayaite pigments Ca(Cr,Sn)SiO5 were obtained from industrial wastes: a marble sawing sludge, a galvanizing sludge from the Cr/Ni process and a foundry sand. The pigments were prepared using the common solid state reaction process. The influence of Cr2O3/SnO2 ratio, calcination temperature and introduced sludges compositions, on its structural stability, was investigated by X-ray diffraction coupled with SEM/EDS. Standard formulations, obtained from commercial reagents, were also prepared and characterized for sake of comparison. CIELab colour measurements and UV-Vis spectroscopy were used to evaluate the stability (thermal and chemical) and applicability of the synthesized pigments in colouring distinct ceramic matrixes fired at high temperatures (1050°C-1200°C). The pigment was added (1/20 wt. ratio) to a transparent and shining lead free glaze and to a porcelain stoneware body (1/10 wt. ratio). The incorporation of three industrial wastes, in the chrome-tin red malayaite pigment, was possible without a notorious change in terms of colouring effect allowing decreasing the synthesis temperature.

Effect of nepheline syenite on the colorant behavior of porcelain stoneware body

Effect of nepheline syenite on the colorant behavior of porcelain stoneware body

Blue cobalt doped-hibonite pigments prepared from industrial sludges: Formulation and characterization

The structural stability of the pigment was investigated using X-ray diffraction coupled with SEM and UV–vis–IR analysis, as a function of the relative Co content and calcination temperature. A standard formulation prepared from commercial reagents was also prepared and characterized for the sake of comparison. The pigment was added to a transparent glaze and to a porcelain stoneware body. Since the relative amount of cobalt was low and the sintering temperature of the pigment was not too high (1350–1400 °C), the new pigment system offers an interesting alternative to spinel, olivine and willemite commercial blue pigments. Moreover, the use of several wastes in the pigment formulation does not diminish its colouring performance.

Rheological behaviour and mechanical properties of porcelain stoneware bodies containing Italian clay added with bentonites

This paper presents the results obtained by replacing German and Ukrainian clays in a porcelain stoneware body with a clay from Sardinia island, Italy, added with 10 wt% of different bentonites available on Italian territory in order to lower the body costs. Two series of bodies were prepared: a first series by substituting completely German clay and partially Ukrainian clay (5 wt%) and a second series by substituting completely the Ukraine clay. Rheological measures were carried out on the suspensions prepared in order to verify the effect of the bentonites presence on the shear and time dependence. The fired specimens were characterized across the technological parameters (water absorption, linear shrinkage, etc.), mechanical and aesthetical properties and compared with a standard/industrial composition.

Dilatometeric study of shrinkage during sintering process for porcelain stoneware body in presence of nepheline syenite

The shrinkage of porcelain stoneware body containing different values of nepheline syenite was investigated. Dilatomeric tests were carried out on suitable specimens to obtain the expansion-shrinkage behavior of ceramic bodies. The differences found in shrinkage data were evaluated by kinetic model and determination of activation energy. The results showed that the activation energy increases with Na 2O + K 2O/quartz ratio and reaches to constant value when 10.0 wt.% nepheline syenite is added to starting composition. The maximum value of shrinkage also approximately remains constant with increasing fluxing agent. It was found that the fluxing effect of nepheline syenite was quite evident with the observed enhanced rate of densification accompanied by the typical compensation effect.