scholarly journals Heating Rate Effect during Sintering on the Technological Properties of Brazilian Red Ceramics

2021 ◽  
Author(s):  
Carlos Guimarães ◽  
Geovana Delaqua ◽  
Afonso Rangel Garcez de Azevedo ◽  
Sergio Neves Monteiro ◽  
Lucas Amaral ◽  
...  
Keyword(s):  
Ceramic Body ◽  
Linear Shrinkage ◽  
Production Costs ◽  
Technological Properties ◽  
Heating Rates ◽  
Rapid Sintering ◽  
Excessive Consumption ◽  
Clay Ceramics ◽  
Red Ceramics

Abstract Unbalanced energy consumption in the production of ceramic artifacts is responsible for considerable undesirable impacts, such as increased emissions of polluting gases, excessive consumption of fuel materials, land degradation and unpredictable financial costs. By contrast, the practice of optimizing the ceramic sintering, which in associated with firing of high temperature, can result in increased productivity and reduced production costs preserving an environmentally friendly production system. Moreover, it allows further improvements in the quality of the final product. This work compares the effect of different sintering cycles, with heating rates of 2, 15 and 30°C/min, on the technological properties of a Brazilian industrial clay ceramic body. Initially the clay ceramic specimens was characterized in terms of mineralogical, chemical and physical properties. Specimens were prepared by extrusion and fired at temperatures of 800, 900 and 1000°C. The evaluated properties by standard tests were water absorption, post-firing linear shrinkage and flexural strength. It was found that owing to sintering carried out at higher heating rates, red ceramic products with superior technological properties were obtained. This is an unprecedented conclusion for common clay ceramics produced in Brazil. Based on the promising obtained results it is evidenced, in a clear and detailed way, the benefits of rapid sintering cycle application for conventional brick production.

Influence of Firing Temperature on the Behavior of Clay Ceramics Incorporated with Elephant Grass Ash

2014 ◽  
Vol 798-799 ◽  
pp. 526-531 ◽  
Author(s):  
Aline Marcia Ferreira Dias da Silva ◽  
Rosane Toledo ◽  
Veronica Scarpini Candido ◽  
Sergio Neves Monteiro ◽  
Carlos Maurício Fontes Vieira ◽  
...  
Keyword(s):  
Water Absorption ◽  
Firing Temperature ◽  
Rupture Strength ◽  
Linear Shrinkage ◽  
Standard Test ◽  
Elephant Grass ◽  
Technological Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Clay Ceramics

The microstructural and technological properties of clay ceramic incorporated with 10 and 20 wt% of elephant grass ashes were investigated at different firing temperatures of 650, 850 and 1050oC. X-ray diffraction were used to obtain the minerals and phase compositions. The microstructure was analyzed by scanning electron microscopy. The technical properties related to water absorption, linear shrinkage and flexural rupture strength were obtained by standard test. The results showed significant changes in the microstructure and phasic composition with increasing firing temperature. A marked improvement in the water absorption, decreasing to 18% as well as increase in strength, above 5 MPa, was found at 1050°C. However, only a slight contribution might be attributed to the incorporation of elephant grass ash. Nevertheless, its use as a by-product and the associated saving in clay are relevant environmental and economical advantages.

Properties of Clay Ceramic Incorporated with Red Mud

2014 ◽  
Vol 798-799 ◽  
pp. 509-513 ◽  
Author(s):  
Michelle Pereira Babisk ◽  
Thalissa Pizetta Altoé ◽  
Henrique Junio de Oliveira Lopes ◽  
Ulisses Soares do Prado ◽  
Monica Castoldi Borlini Gadioli ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Water Absorption ◽  
Red Mud ◽  
Raw Materials ◽  
Linear Shrinkage ◽  
Insoluble Residue ◽  
Technological Properties ◽  
Calcium Aluminates ◽  
Clay Ceramics ◽  
Related Compounds

The red mud is a well known insoluble residue generated in the Bayer process to benefit bauxite ores. This residue is composed of ceramic related compounds such as iron oxide, sodium aluminum silicates, carbonates, calcium aluminates and titanium dioxide. The incorporation of industrial residues in clay ceramics has been extensively investigated, not only as an environmentally correct solution but also as an economic way to save raw materials. Therefore, the present work evaluated the properties of clay ceramics incorporated with up to 40 wt% of red mud. Clay bodies with different percentages of red mud were press-molded and fired at 750, 950 and 1050°C. The evaluated technological properties were linear shrinkage, water absorption and mechanical strength. Sensible changes in such properties were found with red mud addition. In particular, the ceramic fired at 1050°C displayed favorable water absorption with red mud incorporation.

scholarly journals Processing of red ceramic using a fast-firing cycle

Cerâmica ◽  
2012 ◽  
Vol 58 (347) ◽  
pp. 393-399 ◽  
Author(s):  
G. T. Saleiro ◽  
J. N. F. Holanda
Keyword(s):  
Flexural Strength ◽  
Water Absorption ◽  
Ceramic Materials ◽  
Linear Shrinkage ◽  
Important Variable ◽  
Firing Cycle ◽  
Technological Properties ◽  
High Consumption ◽  
Red Ceramics ◽  
Fast Firing

This work reports on the processing of red ceramic for civil construction using fast-firing cycles. The firing cycle is an important variable in the processing of red ceramic materials, which contributes to a high consumption of energy. The red ceramic pieces were prepared by industrial extrusion and fired at firing temperatures varying from 700 ºC to 1100 ºC using different firing cycles (slow-firing cycle - 1º C/min and fast-firing cycle - 10 ºC/min and 20 °C/min). The technological properties (linear shrinkage, water absorption, apparent porosity, apparent density, and flexural strength) as function of the firing temperature and firing cycle are investigated. The development of the microstructure was followed by SEM/SEI. The results showed that fast-firing red ceramics exhibits technological properties and microstructure comparable to conventionally fired red ceramics, resulting in great advantages in energy saving.

Characterization of a Clay Body Used for Red Ceramics in São Sebastião, District of Campos dos Goytacazes, State of Rio de Janeiro, Brazil

2015 ◽  
Vol 820 ◽  
pp. 8-12 ◽  
Author(s):  
Afonso Rangel Garcez de Azevedo ◽  
Jonas Alexandre ◽  
Euzébio Barnabé Zanelato ◽  
Rafael Picanço Oliveira ◽  
Rodolfo Cretton de Souza ◽  
...  
Keyword(s):  
Rio De Janeiro ◽  
Northern Region ◽  
Chemical Characteristics ◽  
Technological Properties ◽  
Clay Deposits ◽  
Clay Body ◽  
Physical And Chemical ◽  
Red Ceramics

The municipal area of Campos dos Goytacazes in the northern region of the state of Rio de Janeiro, Brazil, is the state’s major industrial pole for red ceramic fabrication. The extensive clay deposits and easy to mine conditions have attracted more than one hundred ceramic industries to operate in the area. In particular, the district of São Sebastião contributes to the production of red bricks and tiles but the characterization of the existing clay and the quality of ceramic pieces has not yet been evaluated. Therefore the present work carried out an investigation of a typical clay body used in São Sebastião by means of its physical and chemical characteristics. The technological properties of red ceramics fabricated from this clay body and fired at temperatures of 700, 850 and 1100oC indicate that they comply with the mechanical strength requirements for masonry bricks. However water absorption is not satisfactory due to the excess of sand and lack of fluxing elements.

Reformulation of a Kaolinitic Clay Ceramic Body with Sand and Flux Clay for Roofing Tiles Production

2012 ◽  
Vol 727-728 ◽  
pp. 965-970 ◽  
Author(s):  
Carlos Maurício Fontes Vieira ◽  
Sérgio Neves Monteiro
Keyword(s):  
Mechanical Strength ◽  
Water Absorption ◽  
Rupture Strength ◽  
Ceramic Body ◽  
Linear Shrinkage ◽  
Flexural Behavior ◽  
Ceramic Product ◽  
Technological Properties ◽  
Kaolinitic Clay ◽  
Press Molding

A ceramic body traditionally used to produce bricks and roofing tiles was reformulated by the addition of sand and illitic clay. The objective was to obtain a ceramic product with better technological properties. Specimens were made by uniaxial press-molding at 20 MPa and then fired at temperatures varying from 850 to 1100°C. The determined technological properties were: linear shrinkage, water absorption and flexural rupture strength. The results showed that both sand and illitic clay contribute to reduce the water absorption of the industrial clayey body. With respect to the flexural behavior, it was observed that the incorporation of sand decreased the mechanical strength. On the other hand, the illitic, incorporated in an amounts of 30 wt.% contributed to increase the mechanical strength of the clayey ceramic.

ВЛИЯНИЕ БИОКОНСЕРВАНТА «СИЛОСТАН» НА КАЧЕСТВО СЕНАЖА ИЗ КОЗЛЯТНИКА ВОСТОЧНОГО И СЫРОПРИГОДНОСТЬ МОЛОКА КОРОВ

2019 ◽  
pp. 51-56
Author(s):  
A.S. KARAMAEVA ◽  
N.V. SOBOLEVA ◽  
S.V. KARAMAEV
Keyword(s):  
Serum Proteins ◽  
Metabolizable Energy ◽  
Holstein Cows ◽  
Technological Properties ◽  
Holstein Breed ◽  
Feed Digestibility ◽  
Ayrshire Breed ◽  
Milk Coagulation ◽  
Dry Substance

От породы коров и ее особенностей зависят эффективность использования кормов, качество и технологические свойства молока. Материалом исследований служили коровы чернопестрой голштинской и айрширской пород. Для повышения качества сенажа из козлятника восточного использовали микробиологический препарат. В готовом корме с биоконсервантом содержание сухого вещества было выше на 3,66, обменной энергии на 8,04, сырого протеина на 10,86, переваримого протеина на 13,59. Улучшение качества корма оказало положительное влияние на метаболические процессы в рубце подопытных коров. Независимо от технологии приготовления сенажа коровы айрширской породы лучше переваривали, по сравнению с голштинами, сухое вещество на 2,062,91 (Р0,05), органическое на 1,212,04 (Р0,05), сырой протеин на 2,222,49 (Р0,05), БЭВ на 0,921,36, но при этом голштины лучше переваривали сырой жир на 2,732,78 (Р0,05) и сырую клетчатку на 1,551,86. В результате внесения в сенаж биоконсерванта Силостан и улучшения переваримости корма у коров опытных групп значительно улучшился химический состав и технологические свойства молока. Очень важно для сыроделия, что в молоке коров, получавших в рационе сенаж с биоконсервантом, повышается массовая доля казеина на 2,42,7, а доля сывороточных белков и фракции казеина, которые не свертываются под действием сычужного фермента, наоборот, снижается на 1,41,5 и на 0,30,9, соответственно. Уменьшается продолжительность свертывания молока сычужным ферментом, снижаются потери сухого вещества с сывороткой, и увеличивается выход казеинового сгустка. Плотность казеинового сгустка повышается в молоке голштинских коров на 14,3, айрширских на 5,7 и составляет, соответственно, 1,92 и 2,96 г/см2.The efficiency of feed use, the quality, as well as technological properties of milk depend on cow breed and its characteristics. Blackandwhite Holstein and Ayrshire breeds were used as the material for research. Microbiological preparation was used to increase the quality of halyage made of Eastern galega. The content of dry substance in the readymade feed was 3.66 higher, the metabolizable energy 8.04 higher, raw protein 10.86 higher, and digestible protein 13.59. Improvement of feed quality positively influenced the metabolic processes in the rumen of experimental cows. Without regard to the technology of halyage preparation, cows of Ayrshire breed showed betterdigestion of dry substance by 2.06 2.91 (P0.05) than Holstein cows, organic substance by 1.21 2.04 (P0.05), raw protein by 2.22 2.49 (P0.05), nitrogenfree extractive fraction by 0.92 1.36, but Holstein breed showed better digestion of raw fat by 2.73 2.78 (P0.05) and raw fiber by 1.55 1.86. Chemical composition and technological properties of milk improved significantly as a result of addition of Silostan biopreservative to the halyage and improvement of feed digestibility in cows from test groups. The fact that the mass percentage of casein is increased by 2.4 2.7, and the share of serum proteins and ycasein fractions which do not coagulate under the influence of enzyme rennet is inversely decreased by 1.4 1.5 and 0.3 0.9, accordingly, is very important for cheese making. The duration of milk coagulation with rennet is decreased, the loss of dry substance with serum is decreased, and the yield of casein coagulate is increased. Density of casein coagulate is increased in the milk of Holstein cows by 14.3, Ayrshire cows by 5.7, and equals to 1.92 and 2.96 g/cm2, accordingly.

Resistance to Synthetic Seawater Aggression of Clay Ceramics Incorporated with an Ornamental Stone Residue

2014 ◽  
Vol 798-799 ◽  
pp. 269-274 ◽  
Author(s):  
Gustavo de Castro Xavier ◽  
Jonas Alexandre ◽  
Paulo César de Almeida Maia ◽  
Fernando Saboya Albuquerque ◽  
Leonardo Gonçalves Pedroti ◽  
...  
Keyword(s):  
Firing Temperature ◽  
Standard Procedure ◽  
Degradation Process ◽  
Ceramic Materials ◽  
Linear Shrinkage ◽  
Synthetic Seawater ◽  
Internal Expansion ◽  
Ornamental Stone ◽  
Clay Ceramics ◽  
Chloride Salts

Clay ceramic materials exposed to a marine environment may be subjected to complete degradation due to the presence of chloride salts in the air. The exposition allows the chloride to penetrate in structural pores causing an internal expansion, which eventually split the ceramic apart. In open air, the solar radiation as well as the rain and wind contribute to accelerate the degradation process. In the present work the laboratory assisted degradation of clay ceramics incorporated with a granite residue from ornamental stone processing was evaluated by synthetic seawater aggression according to standard procedure. The amount of incorporated residues, up to 10 wt % and the ceramic firing temperature, up to 900°C, were variable conditions statistically analyzed by factorial planning. Degradation wetting-drying tests were conducted up to 6 months. The results showed that the linear shrinkage of the residue-free ceramics do not stabilize during the test period for any firing temperature. By contrast, the residue-incorporated ceramics tend to stabilize after 4 months. In addition, a decrease in water absorption and flexural strength was observed in same speciemens.

scholarly journals Eating Habits during the COVID-19 Lockdown in Italy: The Nutritional and Lifestyle Side Effects of the Pandemic

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2279
Author(s):  
Federica Grant ◽  
Maria Luisa Scalvedi ◽  
Umberto Scognamiglio ◽  
Aida Turrini ◽  
Laura Rossi
Keyword(s):  
Food Waste ◽  
Eating Habits ◽  
Cross Sectional Study ◽  
Waste Prevention ◽  
Online Questionnaire ◽  
Cross Sectional ◽  
Nutritional Recommendations ◽  
Food And Nutrition ◽  
Excessive Consumption

To limit the spread of coronavirus SARS-CoV-2, a nationwide lockdown started in Italy in March 2020. In this unpredictable situation, a cross-sectional study using an online questionnaire was carried out by the Observatory on Food Surplus, Recovery and Waste of CREA Food and Nutrition Centre. The aim of this work was to evaluate how Italian habits changed during this period, the determinants of changes, and the effect on food waste prevention. In a sample of 2678 respondents, 62% showed low Adherence to the Mediterranean Diet (AMD). During lockdown many of participants improved the quality of their diet, increasing their consumption of fruit (24.4%), vegetables (28.5%), legumes (22.1%), nuts (12%), and fish or shellfish (14%). Unfavorable changes were observed with the excessive consumption of sweets or pastries (36.9%) and comfort foods (22.7%), and a lack of physical activity (37.2%). The main novelty of this study was the examination of dietary changes identified by a cluster analysis. Respondents with generally high AMD improved their eating habits, while the habits of the respondents with generally low AMD remained unchanged. In addition, nearly 80% of respondents were sensitive to food waste. The study provides a useful contribution to the debate on nutritional recommendations in case of further lockdown.

Effect of Green Microstructure and Processing Variables on the Microwave Sintering of Alumina

1990 ◽  
Vol 189 ◽  
Author(s):  
Arindam Dé ◽  
Iftikhar Ahmad ◽  
E. Dow Whitney ◽  
David E. Clark
Keyword(s):  
Particle Size ◽  
Microwave Sintering ◽  
Heating Rates ◽  
Hybrid Heating ◽  
Processing Variables ◽  
Conventional Sintering ◽  
Rapid Sintering ◽  
Temperature Time ◽  
Fast Firing

ABSTRACTThe concept of 'hybrid heating with microwave (MW) energy at 2.45 GHZ.'for ultra rapid sintering of alumina is being introduced. This technique is a combination of MW - materual interaction as well as conventional radiant/conduction mechanisms, and facilitates the attainment of perhaps, the highest possible heating rates in a multimode MW cavity at 2.45 GJZz. (1500ºC in 120 sees.). Rapid sintering of pure.undoped alumina with this novel techniQue culminates in uniform, homogeneous microstructures and mechanical property enhancements vis-a-vis conventional fast firing.The role of green microstructure (particle size) on MW(hybrid) heating and processing variables (temperature, time) on the MW (hybrid) heating phenomena vs. conventional fast firing were investigated. Hybrid heated samples showed accelerated densification with comparable grain sizes when compared with the conventionally fast fired samples. The effectof particle size on the microwave (hybrid) heating phenomena was found to be analogous to conventional sintering.

The Study of How to Extrude the Special Shaft Parts into Form

2013 ◽  
Vol 401-403 ◽  
pp. 908-911
Author(s):  
Xi Ping Bai
Keyword(s):  
Processing Method ◽  
Production Costs ◽  
Cold Extrusion ◽  
Utilization Rate ◽  
Mechanical Processing ◽  
Molding Process ◽  
Technical Problems ◽  
Full Analysis ◽  
Extrusion Forming

In this article, it mainly describes the use of extrusion production process as an example of the special shaft. It gives us a full analysis from the structure of the product, the material problems, the key technical problems needed to be solved, blank preparation processing and the process of extrusion forming. It also introduces the blank dimensions and the calculation method of the extrusion pressure. The method of blank lubrication processing and the process of designing extrusion mould.We are not unfamiliar with the center shaft of the bike. It is one of the important parts in bicycle bottom bracket. It is also a key part to determine the quality of the bicycle. Generally speaking, materials are used is 20 steel. The roughness of the surface is moderate. But the requirement of the product precision is high. We can get it by using mechanical processing method. But it is processing and the efficiency is low. While the utilization rate of mental material is low. So the production costs high. Because the parts production patch is large and the annual production is hundreds of thousands of pieces. In my opinion, it is more reasonable for us to adopt the technology of producing the parts with the cold extrusion precision molding process. Then we can save the materials, improve the efficiency of producing parts, lower the production parts and then meet the requirement of mass production.

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