Production Of Frits Research Articles

An Estimation of Distribution Algorithm-Based Hyper-Heuristic for the Distributed Assembly Mixed No-Idle Permutation Flowshop Scheduling Problem

The distributed assembly mixed no-idle permutation flowshop scheduling problem (DAMNIPFSP), a common occurrence in modern industries like integrated circuit production, ceramic frit production, fiberglass processing, and steel-making, is a new model that considers mixed machines with no-idle restrictions as well as conventional machines. This article introduces an estimation of distribution algorithm-based hyper-heuristic (EDA-HH) to solve the DAMNIPFSP. Ten simple heuristic rules as low-level operations are utilized to search the solution space. The estimation of distribution algorithm is integrated into the framework of hyper-heuristic as the high-level strategy to control the low-level heuristics sequence in the solution space. The destruction and construction procedures are conducted on products and jobs in order to enhance the exploitation competence of EDA-HH. The computational simulation is carried out and the experimental results show that the proposed EDA-HH is significantly superior to the competitors in the statistical sense. The results of the 810 large-scale problem instances show the effectiveness of the EDA-HH in solving the DAMNIPFSP. Moreover, the CPLEX solver is utilized to verify the correctness of the model with some small instances.

Effect of the combustion system on reduction of thermal specific energy consumption in an industrial high temperature process

This paper presents an experimental study carried out in an industrial furnace for frits production using different configurations of burners based on different combustion techniques such as enriched air combustion, flat-flame oxy-combustion and preheater air combustion. The residence time of combustion gases inside the furnace also was modified. Several combustion configurations were tested and its effects on productivity and thermal energy specific consumption and efficiency were determined. The results show that higher residence time of the combustion gases can decrease significantly the specific consumption of fuel, while the change of the burners and combustion techniques did not show significant effects on decreasing the energy consumption. However, it is highlighted that the oxy-combustion flat-flame burners produced the lowest specific consumption of fuel. Even though the experiments were conducted in a furnace for frit production, the corresponding results can also be applied to guide or improve other industrial high temperature processes.

Use of boron mining waste as an alternative to boric acid (H3BO3) in opaque frit production

Colemanite (CaO·3B2O3·5H2) enrichment waste material from mines was employed as an alternative to boric acid (H3BO3) for producing opaque matt frits. The aim of the study was to reduce boric acid consumption and to substitute boron-containing waste material for H3BO3 used for frit production. Laboratory and pilot-scale production was carried out based on frit production methods currently used in the ceramic industry. The frits were then used to produce commercial glossy opaque glazes using existing fabrication and sintering processes with amounts ranging between 16 and 31 wt%. The fabricated glazes successfully passed EN ISO 10545 testing, exhibiting desirable surface abrasion, chemical resistance, thermal shock resistance, and staining characteristics.

Usage of Colemanite in Transparent Wall Tile Glazes

Boric oxide has an important place in glaze technology and is the second most important network-former after silica. Lower thermal expansion coe cient; higherchemical and mechanical durability; good glaze appearance are some of the bene ts of boric oxide. In wall tile production; generally transparent frits with 1 7% boric oxide are used to obtain glossy transparent glaze. It can be said that boric acid is the fourth expensive raw material in frit production after zirconium, zinc oxide and potassium carbonate due to its high cost limits its usage in frit production. The aim of this study is to investigate colemanite (CaB3O4(OH)3·H2O) mineral usage in transparent frit production instead of using boric acid. To achieve this aim, four di erent frit mixtures Std, K.1, K.2 and K.3 with 0 wt.%, 3 wt.%, 6.5 wt.% and 11.5 wt.% colemanite content were prepared respectively. For comparison of the thermal behavior of frits, hot stage microscope was used. It was observed that, all of the samples prepared with colemanite have lower sintering and softening temperatures than the standard recipe because of its high earth alkaline oxide content. The obtained glazes were characterized by X-ray di raction, dilatometer, Harcourt and Autoclave tests.

Environmental management of bottom ash from municipal solid waste incineration based on a life cycle assessment approach

Conventional bottom ash (BA) management consists of a solidification process using inorganic binder reagents, such as cement. However, despite the heavy metal content, the use of BA as a natural aggregate has become increasingly more common. In particular, bottom ash is used as a raw material for clinker, cement mortar or frit production, as a drainage layer in landfills or as a sub-base material in road construction. In this study, the life cycle assessment approach was used to evaluate and compare ash solidification with ash recycling in Portland cement production as a clinker and gypsum substitute. The findings showed that the substitution of ash for clinker resulted in the lowest natural resources (NR) consumption and the lowest environmental burdens (EB). The decrease in the clinker substitution percentage generated a higher NR consumption and an increased EB. In ash recycling, the distance between the incinerator and the cement facility is an important parameter in the decision-making process. Specifically, ash solidification presented less favourable results than ash recycling (with a clinker substitution of 25 %), despite the increasing distance between the incinerator and the cement facility. However, when the clinker substitution decreased to 2.5 % or when ash was substituted for gypsum, the distance played an important role in the water impact.

Numerical and experimental thermal analysis of an industrial kiln used for frit production

This paper describes a methodology for the study and modeling of the thermal energy in ceramic frit melting kilns with an oxy-fired combustion process through the development of a numerical simulation in CFD software. Ceramic frits are vitreous compounds that provide glazes with specific properties for use in the coating of other ceramics, especially those of the ceramic tile industry. The aim of this study is to generate technical subsidies in order to support economically viable proposals for the ceramic industry. The CFD modeling is performed using the commercial software Ansys CFX 11.0, which is based on the method of finite volumes. The geometric domain of resolution consists of the internal cavity of the kiln. The CFD resolution is coupled to a three-dimensional heat conduction code along the kiln walls to determine the external temperature distribution. The thermal problem is composed of the combustion of natural gas with oxygen, the internal turbulent flow of exhaust gases, the energy loss by convection and radiation to the environment through the walls and the radiation within the kiln cavity with participating media. Data collected in an operating kiln are used to verify the numerical solution, achieving a good agreement in the general analysis of the kiln. The numerical solution provides physically consistent results, making it possible to predict the behavior of the kiln as a whole in similar cases with changes in the parameters of the manufacturing process or in the geometry. Other specific results, such as heat flux inside the kiln, are presented and discussed.

Life cycle assessment of ceramic tiles. Environmental and statistical analysis

The aim of this paper is to conduct a life cycle assessment study of ceramic tiles (single-fired glazed stoneware) in order to identify the stages that produce the greatest impact on the environment and the materials and/or processes that make the largest contribution to that impact. The life cycle is considered to be made up of seven stages: (1) mining the clay, (2) atomising the clay, (3) production of frits and glazes, (4) production of ceramic tiles, (5) distribution, (6) installation and usage, and, on ending their useful life (7) treatment as construction and demolition waste. A specific life cycle inventory was developed taking 1 m2 of ceramic tile over a period of 20 years as the functional unit and using annual data gathered directly from 35 Spanish enterprises involved in the different stages of the life cycle of ceramic tiles. This inventory was then used to obtain environmental indicators (global warming, ozone layer depletion, acidification, eutrophication, photochemical oxidation and human toxicity) for each enterprise and each stage of the life cycle under study. Environmental data were submitted to a statistical analysis. This analysis made it possible to model the distribution of environmental behaviour of the life cycle of ceramic tiles considering the different influences from the different companies that were consulted for each stage in the life cycle. The statistical study allowed also obtaining confidence intervals for the mean and standard deviation of the environmental results obtained for each impact category. The stage of the life cycle with the greatest environmental impact for all the impact categories is the manufacture of the tile, followed by the process of atomising the clay and the distribution of the product. There is a direct correlation between these findings and the high level of energy consumption (mainly natural gas and fuel) in these stages. Moreover, the statistical analysis provided 95% level of confidence intervals for the mean and the standard deviation very accurate which shows that using the mean inventory values from all the enterprises that were consulted within the same stage of the life cycle is a suitable method of working. Future users of the inventory may use the probability distributions obtained for calculating percentiles or other measures to assess their data.

Dynamic corrosion of Al2O3–ZrO2–SiO2 and Cr2O3-containing refractories by molten frits. Part I: Macroscopic analysis

Manufacturing of enamels and frits has undergone dramatic changes since the 1980s. This has required significant efforts in research and development. Typical compositions of frits for ceramic tiles are silica-based with fluxing agents; some of the components are highly corrosive. Improvements in the production of frits would imply the selection of the most adequate refractories as a function of the chemical composition of the considered frit and the fabrication procedure.The refractories currently used in frit furnaces are Al2O3–ZrO2–SiO2 (AZS) fused cast materials and Cr2O3-based materials. In this work, results on dynamic corrosion studies of AZS and Cr2O3-based materials by two ZnO-containing frits are described. Experiments have been performed using the “Merry Go Round” test at ≅1500°C. Macroscopic results are analysed in terms of the remaining volume after the tests, as usually done in the glass industry. The significance and limits of such an approach are discussed.

Use of Incinerator Bottom Ash for Frit Production

SummaryThis article presents the results of an experimental activity aimed at investigating the technical feasibility and the environmental performance of using municipal solid waste incineration bottom ash to produce glass frit for ceramic glaze (glaze frit). The process includes an industrial pretreatment of bottom ash that renders the material suitable for use in glaze frit production and allows recovery of aluminum and iron. The environmental performance of this treatment option is assessed with the life cycle assessment (LCA) methodology. The goal of the LCA study is to assess and compare the environmental impacts of two scenarios of end of life of bottom ash from municipal solid waste incineration (MSWI): landfill disposal (conventional scenario) and bottom ash recovery for glaze frit production (innovative scenario). The main results of the laboratory tests, industrial simulations, and LCA study are presented and discussed, and the environmental advantages of recycling versus landfill disposal are highlighted.

Production of opaque frits with low ZrO2 and ZnO contents and their industrial uses for fast single-fired wall tile glazes

The amounts of zirconium and zinc oxides, which raise the production costs of ceramic glazes, were decreased in fast single-fired wall tile frit compositions and an industrial frit production was conducted. Opacity of the fired frit-based glazes was accomplished by compositional modifications of frits with no other nucleating agent. It was determined that the ratios of Al2O3/ΣR2O, Al2O3/ΣRO, and Al2O3/B2O3 have significant effects on decreasing ZrO2 and ZnO levels in the frit composition. A reduction of 25% in both zirconia and zinc oxide contents of frit batches, with respect to the reference frit (R) containing 6–10% ZrO2 and 6–10% ZnO for a glossy white opaque wall tile glaze, was achieved in the ZD glaze consisting of 4.5–7.5% zirconia and 4.5–7.5% ZnO in its frit composition. It was concluded that zircon was the main crystalline phase of the glaze contributing the opacity. The ZD frit-based glaze has a thermal expansion coefficient value of 61.13 ± 0.32 × 10−7 °C−1 at 400 °C which well matches to that of the wall tile body. TS EN ISO 10545 standard tests were also applied to the final ZD glaze. It is confirmed that the production cost of a fast single-fired wall tile glaze can be decreased by 15–20% with the successful new frit developed.

Zircon-free frits suitable for single fast-firing opaque wall tile glazes and their industrial productions

Wall tile glazes with a smooth surface texture, high glossiness, and whiteness are usually based on zirconium containing frits. However, these frits are quite expensive and therefore, there have recently been certain attempts to lower the production cost such as taking suitable glass–ceramic glaze systems into an account. With the present work, the frit-based glaze compositions belonging to the K 2O–MgO–CaO–ZnO–Al 2O 3–B 2O 3–SiO 2 glass–ceramic system were studied to prepare newly synthesized wall tile glazes for industrial single fast-firing. The design of a glass–ceramic glaze for this type of tiles should ensure that the selected frit precursor is technically and commercially compatible with the manufacturing conditions generally used in the production of glazed ceramic wall tiles. The aim of the study is to develop zircon-free, frit-based, glossy opaque glass–ceramic glazes for wall tiles by optimizing the CaO/MgO and adjusting the Al 2O 3/alkali ratios in the starting frit compositions. Frit production, glaze preparation, application, and single fast-firing of wall tiles were, first of all, conducted under laboratory working conditions and then, successful recipes were adapted to the relevant industry. The frit crystallization capability and crystallization temperature range were determined by differential thermal analysis (DTA). Thermal expansion coefficient values of glazes were determined by a dilatometer. Characterization of single fast-fired glass–ceramic glazes was made by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques. Colour and gloss analyses of the final glazes were measured with a spectrophotometer and a gloss meter, respectively.

The production technology of Egyptian blue and green frits from second millennium BC Egypt and Mesopotamia

The microstructures and chemical compositions of some 55 Egyptian blue and green frit samples from New Kingdom Egypt and 15th century BC Mesopotamia are determined using analytical scanning electron microscopy, the main focus being on frit cakes, powder residues, and frit vessel and bead fragments from one of the “factory areas” at Amarna in Middle Egypt. Replicate Egyptian blue frits produced in the laboratory are similarly investigated. Comparison of the microstructures of the ancient and replicate samples suggest that frit cakes are the primary product, and that these were ground to produce the powder, and then moulded to shape and refired to produce the vessels and beads. Egyptian blue and green frits are shown to be distinct pigments, the pigment produced depending on the relative proportions of copper oxide and lime in the mixtures. The bulk and glass phase compositions are used to try to infer the different sources of the quartz, lime, copper and alkali flux used in the production of frits from Egypt and Mesopotamia. An estimate is made of the scale of production of Egyptian blue frit in New Kingdom Egypt.