scholarly journals Characteristics of Thermal Parameters and Some Physical Properties of Mineral Eutectic Type: Petalite–Alkali Feldspars

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7321
Author(s):  
Agata Stempkowska

The aim of the research was to check whether the system of three fluxes based on lithium aluminium silicate and alkali feldspars has a eutectic point, i.e., with the lowest melting temperature. Lithium was introduced into the mixtures in the form of petalite, which occurs naturally in nature (Bikita Zimbabwe deposit). Using naturally occurring raw materials such as petalite, sodium feldspar, and potassium feldspar, an attempt was made to obtain eutectics with the lowest melting point to facilitate thermal processing of the mineral materials. In addition, the high-temperature viscosity of the mineral alloys and physical parameters such as density, linear shrinkage, and open porosity were studied. The study showed that in these systems, there is one three-component eutectic at 1345 °C, with the lowest viscosity of 1·105 Pas and the highest density of 2.34g/cm3, with a weight content of petalite 20%, sodium feldspar 20%, and potassium feldspar 20%.

2018 ◽  
Vol 25 (1) ◽  
pp. 84-99 ◽  
Author(s):  
Shihab A. Zaidan ◽  
Shahad Sarmed Abdull-Razzak

Porcelain is one of the most important ceramic materials with a wide range of traditional and technical applications. Since most mixtures of porcelain have a high sintering temperature, bentonite has been added in this research to improve the characteristics of sintering and burning. The porcelain mixture consisted of the following Iraqi raw materials: 30% wt kaolin, 30 wt% non-plastic clay (grog), 10% wt sodium feldspar, 10 wt% potassium feldspar and 20 wt% flint. After the mechanical mixing process and transfer the powder mixture to the slurry by adding distilled water, then different weight percentage of the sodium bentonite(0, 2.5, 5, 7.5 and 10) wt% was added. The specimens were prepared by using the solid casting method, and after the drying process, the specimens were burned at1100 oC. The results of x-ray diffraction showed that bentonite reduced the crystallization of the main ceramic phases (mullite, quartz), which stimulates the appearance of amorphous glass phases. Also, the loss of mass on ignition increased when the addition of bentonite from 5.66% to 8.2%. There was also a great convergence between the granules of porcelain when adding bentonite and thus increase the shrinkage of the dimensions from 9.33% to 12.37 %. This led to increasing the bulk density from 1.97 g/cm3 to 2.67 g/cm3 at firing temperature 1100oC, and the porosity was decreased from 17.1% to 1.44%. Diametrical strength and flexural strength (bending) increased with bentonite (14.88 to 34.46MPa), (6.2 to 8.65 MPa), respectively.  


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4334
Author(s):  
Agata Stempkowska

In this paper, the system of natural mineral alkali fluxes used in typical mineral industry technologies was analyzed. The main objective was to reduce the melting temperature of the flux systems. Particular attention was paid to the properties of lithium aluminium silicates in terms of simplifying and accelerating the heat treatment process. In this area, an alkaline flux system involving lithium was analyzed. A basic flux system based on sodium potassium lithium aluminosilicates was analyzed; using naturally occurring raw materials such as spodumene, albite and orthoclase, an attempt was made to obtain the eutectic with the lowest melting point. Studies have shown that there are two eutectics in these systems, with about 30% spodumene content. The active influence of sodium feldspar was found.


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 410 ◽  
pp. 699-703
Author(s):  
Valeriya È. Shvarczkopf ◽  
Irina A. Pavlova ◽  
Elena P. Farafontova

The research focuses on the properties of by-products formed in the production of porcelain stoneware: polishing residue and residue of the mixture-preparation shop. The polishing residue consists of glassy phase (80%), quartz (14%), mullite (5%). Residue of the mixture-preparation shop consists of quartz (~ 18%), muscovite (~ 6.9%), kaolinite (~ 20.5%), calcium-sodium feldspar (~ 51.4%), diopside (~ 2.98%). Polishing residue occurs when polishing porcelain stoneware to create a glossy surface and when polishing the side faces of porcelain stoneware to obtain accurate tile geometry. The particle size of the polishing residue is less than 0.2 mm, and the residue of the mixture-preparation shop is less than 40 microns. Residue of the mixture-preparation shop is formed when cleaning equipment: mills, mixers, slipways, etc. The ways of utilization of by-product are follows: as a filler for the silicate production; for polymer-cement, water-dispersion and oil paints; as a filler for the production of roofing materials, bituminous roofing mastics based on organic binders; raw materials for the production of foam glass materials and products.


Cerâmica ◽  
2013 ◽  
Vol 59 (351) ◽  
pp. 473-480 ◽  
Author(s):  
K. C. P. Faria ◽  
J. N. F. Holanda

The sugarcane industry generates huge amounts of sugarcane bagasse ashes (SCBA). This work investigates the incorporation of a SCBA waste as an alternative raw material into a clay body, replacing natural clay material by up to 20 wt.%. Clay ceramic pieces were produced by uniaxial pressing and fired at temperatures varying from 700 to 1100 ºC. The technological properties of the clay ceramic pieces (linear shrinkage, apparent density, water absorption, and tensile strength) as function of the firing temperature and waste addition are investigated. The phase evolution during firing was followed by X-ray diffraction. The results showed that the SCBA waste could be incorporated into red ceramics (bricks and roofing tiles) in partial replacement for natural clay material. These results confirm the feasibility of valorisation of SCBA waste to produce red ceramic. This use of SCBA can also contribute greatly to reducing the environmental problems of the sugarcane industry, and also save the sources of natural raw materials used in the ceramic industry.


Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2383
Author(s):  
Daniele Torsello ◽  
Mattia Bartoli ◽  
Mauro Giorcelli ◽  
Massimo Rovere ◽  
Rossella Arrigo ◽  
...  

We report on the microwave shielding efficiency of non-structural composites, where inclusions of biochar—a cost effective and eco-friendly material—are dispersed in matrices of interest for building construction. We directly measured the complex permittivity of raw materials and composites, in the frequency range 100 MHz–8 GHz. A proper permittivity mixing formula allows obtaining other combinations, to enlarge the case studies. From complex permittivity, finally, we calculated the shielding efficiency, showing that tailoring the content of biochar allows obtaining a desired value of electromagnetic shielding, potentially useful for different applications. This approach represents a quick preliminary evaluation tool to design composites with desired shielding properties starting from physical parameters.


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


2019 ◽  
Vol 51 (2) ◽  
pp. 189-197
Author(s):  
Ye Li ◽  
Hengze Zhao

Cordierite ceramic was fabricated by reducing Al2O3 mole ratio from 2.0 to 1.4 with kaolin, silicon dioxide and magnesium oxide as the raw materials. The effect of reduced Al2O3 mole ratio on the sintering behaviors, phase transition, main properties, and microstructure were characterized in detail. The results show that cordierite phase becomes the main crystallization phase at 1300?C, and mullite phase can be consumed to produce cordierite phase by reducing Al2O3 mole ratio. But additional quartz phase still exists until 1400?C. Moreover, the open porosity, pore connectivity and pore size increase as Al2O3 mole ratio reduces from 2.0 to 1.4 while the linear shrinkage percent and bulk density decrease with the reduced Al2O3. It is considered that the sintering activity of the raw materials at low temperature decreases due to the increase of chemically pure magnesium oxide and silica with the decrease of Al2O3 mole ratio, while the crystallization process, pore growth and cordierite phase rather than the liquid phase control the densification process at high temperature.


2008 ◽  
Vol 26 (No. 5) ◽  
pp. 309-323 ◽  
Author(s):  
H. Vlková ◽  
V. Babák ◽  
R. Seydlová ◽  
I. Pavlík ◽  
J. Schlegelová

Microbial biofilms which form on all types of surfaces of technological systems in the dairy industry and on dairy farms adversely affect the quality and safety of final products, i.e. both foodstuffs and raw materials used for their production. The fact that a number of microorganisms are alimentary pathogens, e.g. <I>Staphylococcus aureus</I> or <I>Listeria monocytogenes,</I> makes a serious problem directly affecting human health. Biofilms are usually formed by various species of microorganism, which protect each other against the effects of biocidal (antibacterial) agents and are resistant to these agents. The colonisation of surfaces of the open and closed piping systems, floors, waste, walls and ceilings of the production halls becomes a major problem in the selection of effective sanitation agents for their control. Based on the existing model studies, practical methods for testing the effectiveness of sanitation procedures should be evaluated, including the selection of biocides and comparison of the physical parameters of the sanitation procedures. Testing the effectiveness of the sanitation agents should be performed with the use of standardised tests, which consider microbial, structural, and chemical characteristics of the living microbial communities on specific contact surfaces in the food-processing industry.


2015 ◽  
Vol 1088 ◽  
pp. 395-398
Author(s):  
Luiz Oliveira Veriano dalla Valentina ◽  
Marilena Valadares Folgueras ◽  
Wanessa Rejane Knop ◽  
Maria Cristina Pacheco do Nascimento ◽  
Glaucia Aparecida Prates

The work evaluates the possibility of the use the exhauster powder generated in the foundry process in ceramic mass atomized semigre type. The raw materials used were semi-stoneware kind atomized powder used on the coating ceramic manufacturing and dust exhaust byproduct supplied by a foundry industry both from brazilian industries . Tests were conducted using a heating rate of 10o.C / min and oxidant and / or inert atmosphere. Specimens contained different amounts of byproduct to the extent of 30% by mass, in order to verify the maximum addition of byproduct and were used in order to analyze the technological properties evaluation (water absorption linear shrinkage, bulk density). at the temperature of 1100 ° C showed higher difference between the results obtained and 1200o C this difference decreased.


Sign in / Sign up

Export Citation Format

Share Document