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Regret for the inconvenience: we are taking measures to prevent fraudulent form submissions by extractors and page crawlers. Received: August 07, Published: August 24, Study for vitreous waste recovery in the formulation of heavy clay ceramics. DOI: Download PDF. The study was to analyze the technical feasibility of the incorporation of vitreous waste, from enamel decanters, into a heavy clay mass for fired clay ceramic structural block production.
The analyzed waste is considered as class I—Dangerous due to the presence of toxic elements in the leachate above the Brazilian waste classification standard. Chemical and mineralogical characterization tests of the raw materials carried out.
The technological properties evaluated were linear thermal retraction of drying and firing, loss on fire, water absorption and mechanical resistance. Where it was possible to decrease the water absorption and increase the mechanical strength. This work also contributes to the reduction of the environmental impact and favors the sustainable development of the heavy clay ceramics contributing to the improvement of the quality of the pieces.
Keywords : heavy clay ceramic, waste recovery, vitreous waste, fired clay ceramic structural block. Over time, the planet's natural resources, formerly considered abundant, have been used indiscriminately generating significant amounts of solid waste. However, this practice has caused serious environmental problems. The civil construction sector, particularly in the manufacture of inputs, is constantly increasing with great potential impact. The economy already gives indications that will grow again which will improve the construction market.
Therefore, recycling or re-use within the same process can be a reasonable way of preserving the environment. However, increasing the value of by-products using the waste recovery methodology has been a sustainable alternative to avoid their disposal in soil conditioners or landfills. Such a tool considers industrial wastes as by-products or alternative materials that can feed another industry.
Currently produced ceramic coatings are generally composed of three distinct layers: the ceramic support, the englobe and the enamel. Ceramic materials are among those most traditionally used in the construction sector. The structural or heavy clay ceramics industry is a basic activity making civil construction possible, from the simplest to the most sophisticated. This segment which mainly produces perforated bricks, solid bricks, slab components, hollow and structural blocks, tiles, shackles and rustic floors.
Is very important in generating income in the Brazilian industrial sector. The annual global of ceramic for masonry production is currently around billion and its demand is expected to grow steadily. Such a productive increase demands a large amount of raw material which generates environmental problems related to the scarcity of natural resources.
Although the sector has a great environmental degrading potential due to mineral extraction by the high consumption of clay. The manufacture of red ceramics is able to absorb high amounts of solid residues from several segments, mainly due to the large volumes involved, allows greater tolerance in the composition of its mass. This factor causes the number of researches to increase the incorporation of a series of residues in ceramic mass, such as glass, 14 , 15 ashes of the most diverse sources, 16 mining wastes, 19 sludge from a wide variety of treatment sources, 20 waste from heavy clay ceramic process 23 and other wastes.
Therefore, innovative approaches to the production of heavy clay ceramics that are less dependent on virgin sources are highly encouraged from the perspective of protecting natural resources and sustainable development. Within this premise, the study aims to take advantage of a residue from the manufacture of ceramic coating.
More specifically the enamel industry as a raw material to incorporated with the manufacture of ceramic blocks for masonry. The waste it is a ceramic sludge, rich in vitreous and fluxing materials that if deposited in inappropriate places cause contamination of the environment. Mainly because it contains significant quantities of heavy metals lead and cadmium and considerable proportions of aluminum. The ceramic residue used in this work provided by a Brazilian company from Santa Catarina state from the process of washing and residues of enamels.
The ceramic mass supplied by a ceramic company from South of Santa Catarina, Brazil used for the manufacture of structural blocks. The clay mass was obtained from the mixture of four clays that was collected after complete homogenization and removal after the rolling process.
The ideal moisture for making these specimens is determined by the Pfefferkorn plasticity assay. Being a ratio of the initial measure to the final.
For this procedure the weighings of the Standard Mass STD and also of the waste were carried out with a balance electronic mark, model SF with a maximum capacity of 10 kg.
The amount of sample prepared was 1 kg for each formulation and then homogenized manually with the help of a metal spatula and then an eccentric mixer. The duly identified formulations were packed in hermetically sealed plastic containers for moisture homogenization for a period longer than 24 h.
The conformation was formulated using a laboratory press with a capacity of 15 tons. Ten samples were pressed for each formulation in a total of 60 samples at a pressure of 5 tons. The samples are press with diameters of 73 mm and thickness of 15 mm identified, weighed, and measured. This procedure was adopted in order to guarantee the same conditions established by the industrial process.
After the burn, the samples were characterized by linear retraction of burning, loss of ignition, mechanical resistance to flexion diametric compression in a universal machine of mechanical tests EMIC model DL and water absorption. Table 2 shows the chemical composition of the raw materials obtained by X-ray fluorescence spectrometry FRX , where it is possible to verify the predominance of silica SiO 2 and alumina Al 2 O 3 in all samples.
Silica is found in several mineralogical phases, clayey and non-clayey, especially quartz its purest natural form and kaolinite Al 2 Si 2 O 5 OH 4. Alumina is also generally associated with kaolinite, being a very characteristic mineralogical phase of clays .
At lower levels, iron oxide Fe 2 O 3 0. Iron oxide is known to favor reddish tones in the burned parts and by the fluxing effect in the ceramics. It can be observed that the waste presents significant levels of alkaline earth metals, mainly calcium oxide this also contributes to assist the sintering of the ceramic mass in certain temperatures. The presence of calcium CaO , magnesium MgO and potassium K2O assist with increasing resistance to sudden changes in temperature.
The presence of silica SiO2 in main content is an indicator that the residue can improve the quality of the piece, mainly in the mechanical strength, since it is an oxide flux related to the verification of the material.
The results also indicated that the residue is not flammable. In a mixture with water in a ratio of by weight, it has a pH of 9. Table 3 shows the parameters tested for toxicity in the leaching test. Due to the results obtained during the leaching test, the residue is toxic because it contains barium and lead in concentrations.
Table 4 presents the results of the Raw Residue of the STD and enamel waste, showing that the residue used has a smaller particle size than the standard mass, directly aiding in the packaging factor, contributing to a better compaction.
The results expressed in Figure 1 indicate that samples containing approximately This content is the standard for the accomplishment of the conformation of the specimens. The graph of Figure 2 shows the results of total linear thermal retraction drying and firing of the formulations and standard mass STD used in the study. It is possible to observe that in the linear retraction of drying the results decrease with the increase of the added waste.
The burning tends to reduce the amount of organic material present in the clays and its dimensions too. Therefore, it is possible to analyze the difference in the linear retraction of burning of the formulations.
As the waste content increases it also increased retraction, because of the waste having considerable amounts of fluxing materials as shown in Table 2 , which aids in the fusion of the piece, causing the retraction.
According to Figure 3 , the loss of ignition of the standard mass and of the formulations was coherent, since they presented values between 5.
The results also indicate a reduction in loss of ignition as the residual content increases, since the residue presents a lower amount of organic matter 4. The results of mechanical strength obtained by the diametrical compression method and the water absorption presented in the graph Figure 4. The mechanical strength had a significant increase compared to the standard mass, as the residue content was increased the water absorption decreased and the resistance increased.
Formulations F5 and F6 showed higher strength 5. Again, these results are related to the considerable content of fluxes in the waste.
This favors the formation of liquid phase in the sintering process. Reducing the amount of pores favoring the reduction of water absorption and the increases of the mechanical resistance. Which for companies this is of fundamentally important because it guarantees the quality of the final product. Through the work carried out, it can be said that the addition of the enamel waste to the clayey mass of heavy clay ceramics influences its properties.
Changing its characteristics in the finished product. It is a flux waste the silica base when sintered forms a liquid phase, decreases the porosity of the material, and causing a sintering faster or at a lower temperature. Additions from enamel waste contributed to the increase of physical properties such as burning retraction, mechanical resistance to bending, and decreased water absorption and loss of ignition.
The higher the addition the more intense this effect. These tailings have the potential to be used as an alternative raw material in the manufacture of heavy clay ceramics and therefore, from a manufacturing point of view, can be used as a great flux that still generates improvements in the characterization of the final product and gains in sustainable marketing.
With this waste it can possible of introducing faster firing cycles. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and build upon your work non-commercially. Withdrawal Policies Publication Ethics. Research Article Volume 1 Issue 2. Figure 1 Index of plastic deformation by the humidity of the plasticity test by Pfefferkorn test.
Figure 2 Linear thermal retraction of the formulations studied. Figure 3 Loss of ignition of the standard mass and formulations used in this research.
Figure 4 Water absorption versus mechanical resistance to diametric compression of the formulations carried out in the research. Surface properties of new green building material after TiO2—SiO2 coatings deposition.
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ABNT NBR ISO 10007:2005-03-30