scholarly journals Influence of forming pressure on frost resistance of ceramics

2021 ◽  
Vol 2 (1(58)) ◽  
pp. 15-20
Author(s):  
Іrіna Subota ◽  
Larysa Spasonova ◽  
Аnastasia Sholom

The object of research is low-melting clays of the Kyiv region (Ukraine). The work is devoted to the study of obtaining ceramic materials resistant to low temperatures. Frost resistance is one of the most important characteristics for regions in which ceramic materials are used with frequent temperature transitions through 0 °C. The production of frost-resistant ceramic wall materials is determined by the type of raw materials and technological production parameters. The main technological methods for increasing frost resistance are: the use of less dispersed clays; batch homogenization; formation of raw material without textural defects and prevention of cracks during drying and firing. The work shows that the existing methods for increasing frost resistance can be implemented by reducing water absorption due to the creation of a microporous structure with predominantly closed pores by increased pressure of a semi-dry method of formation. An increase in the pressing pressure leads to an increase in the number of contacts of the molecules of the ceramic mass at the stage of formation. Due to this, the strength of the molded samples at a pressing pressure of more than 30 MPa is higher compared to samples molded by the plastic method. It was also found that an increase in the pressing pressure makes it possible to speed up the drying process of ceramic products, reducing energy consumption for their production. Due to an increase in the pressing pressure to 50 MPa, the strength of samples obtained by semi-dry pressing is 55.4 MPa, while for samples during plastic formation it is 22.9 MPa. Water absorption, on the contrary, for dry pressing is 9.3 %, while for plastic pressing it is 12.2 % at a firing temperature of 1000 °C. It is shown that increasing the pressing pressure is an effective way to improve the quality of ceramic materials based on local low-plasticity clay raw materials. Saving natural and energy resources, developing new sources of raw materials and comprehensive improvement of products with environmental friendliness of production remain important today.

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 961
Author(s):  
Angeliki Christogerou ◽  
Paraskevi Lampropoulou ◽  
Dimitrios Papoulis ◽  
George N. Angelopoulos

The objective of this study was to investigate the valorization potential of clayey overburden sterile materials from lignite-mining activities in the manufacturing of traditional ceramics. This study aims to contribute toward the sustainable management and use of such waste materials in line with the environmental objectives of the 2030 agenda. To assess this issue, clayey steriles were incorporated in a white clay-body at 20, 50, and 80 wt%, whereas reference samples were also formed from the individual raw materials. Laboratory processing of the ceramics was performed by dry pressing loose powder into rectangular samples and firing at 1000 °C for 4 h. Characterization of the raw materials included chemical, mineralogical, and thermal analysis. The fired bodies were tested for their total linear shrinkage, apparent porosity, water absorption, bulk density, and bending strength according to the relevant standards. The microstructural evolution of the final bodies was analyzed by scanning electron microscopy, which observed differences related to the addition of the steriles. The results showed that the tested clayey steriles can be utilized up to 50 wt% as a secondary raw material in the production of ceramic materials (e.g., bricks) with comparable properties to the reference clay-bodies. Furthermore, the color of the final samples changed from white-creamy to reddish as the content of clayey sterile materials increased in the raw mix.


2020 ◽  
Vol 120 ◽  
pp. 126-133
Author(s):  
V. V. Martynenko ◽  
Yu. A. Krakhmal ◽  
K. I. Kushchenko ◽  
T. G. Tishina

Lightweight materials are widely used in industry for thermal insulation of various thermal units. The choice of lightweight material depends on the specific conditions of service. For the lining of high-temperature units operating in reducing environments, alumina lightweight products are used that contain a minimum amount of Fe2O3 impurities and free (unbound in compounds) SiO2. In JSC “URIR named after A. S. Berezhnoy” a technology of alumina lightweight products of grades KLA-1.1 and KLA-1.3 by a semi-dry pressing method with an application temperature of up to 1550 °C has been developed. These products are made from a mixture of ground and no-milled γ-form alumina of grade 0 and α-form alumina of grade S with additives of pitch coke and chalk. The work purpose was improvement of the alumina lightweight products technology and search for new alternative raw materials along with the currently used alumina grade S. The properties dependence of alumina lightweight products, obtained by the semi-dry pressing method, on the type of alumina α-form, was investigated. As a result of the studies, it was found that, for the manufacture of alumina lightweight products of grades KLA-1.1 and KLA-1.3 by the semi-dry pressing method, alumina grades N and NR can be used as an alternative alumina-containing raw material along with alumina grade S. The phase composition of alumina lightweight products of grades KLA-1.1 and KLA-1.3, which are manufactured using alumina grades S, N and NR, was represented mainly by corundum and calcium hexaluminate. The alumina lightweight products, which were manufactured using alumina grades S, N and NR, were characterized by similar high properties and correspond the technical requirements for grades KLA-1.1 and KLA-1.3.


2020 ◽  
Vol 992 ◽  
pp. 253-258
Author(s):  
M.P. Lebedev ◽  
V.N. Tagrov ◽  
E.S. Lukin

The article deals with the manufacture of modern structural ceramic materials from clay and loam deposits of the Republic of Sakha (Yakutia). The importance and relevance of the development of the production of building materials from local raw materials is emphasized, since this will certainly affect the effectiveness of the construction complex as a whole. The successful development of the construction complex is capable of not only stimulating growth in all sectors of the economy, but also contributes to solving the most pressing social problems. Today, Yakutia has huge reserves of mineral raw materials for the production of a wide range of building materials and products. Of practical interest are wall materials made from clay soils. Given the features of the region’s raw material base, this work focuses on additional processing of traditional material. Controlling the complex physicochemical and structural-mechanical transformations that occur during heat treatment, a methodology has been developed for creating a composite material that will allow competitive innovative materials with enhanced strength properties to be produced with a reinforcing element with a glassy phase matrix of mullite crystals. The fabricated samples have a wide range of physical and mechanical properties and allow using it as a high-quality structural building ceramics, as well as industrial floor technical tile.


Author(s):  
Widya Sari ◽  
I Wayan Budiarsa Suyasa ◽  
I.G.B Sila Dharma

ABSTRACT        The production of pig manure waste potentially pollutes the soil, water and air. One of the most effective processing a waste treatments is through composting. The composting process takes a long time if not assisted by the activator as decomposers of organic materials in order to accelerate the composting process. Activators such as local microorganism (MOL) contain macro nutrients, micro and active microorganism that potentially decomposed organic materials, growth stimulants and pest/disease control agents such as to help speed up the composting process. This study aims to determine the C/N ratio of optimal raw materials for composting of pig manure and vegetable waste, determining the effect of adding local microorganism (MOL) to the length of time of composting and determining the effectiveness of business from composting of pig manure and vegetable waste based on the calculation of B/C ratio.        This research uses quantitative approach with experiment method. The first stage is the preparation of the raw material which is divided into three groups : composition 1 with 75% (pig manure) and 25% (vegetable waste), composition 2 with 50% (pig manure) and 50% (vegetable waste) and then composition 3 with 25% (pig manure) and 75% (vegetable waste). Furthermore, the best raw material composition was treated with variations of MOL addition of A (100 ml), B (300 ml), C (500 ml) and D (without MOL).        The results showed that the composition of the best raw material mixture was a mixture composition of 25% (pig manure) and 75% (vegetable waste) with a C/N ratio of 38.95. The effect of MOL addition indicates that the greater MOL volume the faster to composting process. The quality compost with addition of MOL has C/N ratio levels is (16,30), N-total (1,65%), P tersedia (8043,02 ppm), K tersedia (8857,40 ppm), Fe (1,87%), Mn (0,09%) Zn (480 ppm) in which that value meets the SNI 19-7030-2004. Based on analysis of B/C ratio obtained result of 1.04 where the value is approaching criteria B/C ratio more than 1.00 which means compost business feasible to be developed.   Keywords : Pig manure, MOL, time of composting, composter, B/C ratio


2019 ◽  
Vol 974 ◽  
pp. 419-423
Author(s):  
Victoria Gurieva ◽  
A.V. Doroshin

The paper presents the fundamental possibility of using ash and slag waste (ASW) of the fuel and energy complex in the production of ceramic bricks using the semi-dry pressing method based on the Buguruslan deposit low-melting aluminosilicate loams. The technological parameters optimization ways (molding moisture, grinding fineness, pressing pressure) in the production of ceramic bricks from low-quality clay raw materials using the experiment mathematical planning method are presented. The separate and joint grinding raw materials mixture rational composition influence on the ceramics technological properties is studied.


2011 ◽  
Vol 383-390 ◽  
pp. 3366-3373
Author(s):  
Shuo Qin ◽  
Bo Lin Wu ◽  
Shiao Zhao ◽  
Cong Chang Ma ◽  
Zu Sheng Hu

Red mud is the main solid residue generated during the production of alumina by means of the Bayer process. In order to expand the comprehensive utilization field of red mud and develop new ceramic products with low radioactivity utilizing red mud, the exploration of preparing self-releasing glaze ceramic materials using red mud as raw material was carried out. During the exploration, the self-releasing glaze ceramic materials with low radiation level were produced by normal pressure sintering process using the main ingredients of red mud, red sandstone, barium carbonate and ball clay. The properties of the self-releasing glaze ceramic samples were investigated by the measurements of mechanical properties, X-ray diffraction (XRD), scanning electron microscopy (SEM) and radiation measurement. The results show that the self-releasing glaze ceramic materials have good mechanical properties (the bulk density, 3.10 g/cm3; the compressive strength, 78.00 MPa). Adding barium carbonate to the raw materials and then calcine them to ceramics, which can extend the sintering temperature range and the radioactivity level of the self-releasing glaze ceramic materials can be reduced to that of the natural radioactive background of Guilin Area, Karst landform (the average 60 Total/Timer).


2014 ◽  
Vol 798-799 ◽  
pp. 240-245 ◽  
Author(s):  
Leonardo Leandro dos Santos ◽  
José Elson Soares Filho ◽  
Liszandra Fernanda Araújo Campos ◽  
Heber Sivini Ferreira ◽  
Ricardo Peixoto Suassuna Dutra

Much industrial waste has mineralogical, chemical and physical characteristics similar to clays used in ceramic materials, enabling the reuse of these as raw materials in the ceramic industry. The ashes are a type of waste containing metals, which can cause air pollution, responsible for serious respiratory problems in the affected population. This study investigate the use of waste derived from the carbonization of a solid fuel (wood) in ceramic paste used for the manufacture of rustic floors, aiming its incorporation into the mix, partially replacing (lessening the environmental problem) the usage of raw material (saving clay), enabling the analysis of certain variables of sample preparation (characterization and formulation) and their influence on the final properties of the material. Results indicate that the partial replacement of clay by ash is feasible in the chemical and mineralogical aspects in the formulation of ceramic paste in the manufacturing of rustic floors.


2018 ◽  
Vol 12 (1) ◽  
Author(s):  
I. Bilenka ◽  
Ya. Golinskaya ◽  
N. Dzyuba ◽  
H. Martirosian

In the work, various technological methods are presented of preliminary processing of celery and parsnip roots to prevent their darkening during cooking in restaurants. These methods are: immersing in a citric acid solution (c = 0.05 %, 0.1 %, 0.15 %), in solution NaCl (c = 0. 5%, 1 %, 2 %), and microwave processing in various modes. The activity of peroxidase, polyphenol oxidase, and ascorbate oxidase enzymes of root crops in the varietal section is also determined. Fresh white roots were selected as research objects: celery of the varieties Yablucnyy and Diamant, and parsnip of the varieties Student and Kruhlyy. It was revealed that polyphenol oxidase shows the highest activity. In order to inactivate the above-stated oxidoreductase, different methods of treating white roots were compared, too. The lowest oxidative enzymes activity was characteristic of the roots of the Diamant varieties and the parsnip roots of the Student variety, which were selected for further work. Studies have been carried out on changes in the mass fraction of L-ascorbic acid during steam blasting and microwave processing in different modes. It is proved that the treatment of white roots with ultra high frequency irradiation at 650 W for 1 minute is optimal. Such treatment allowes preventing the darkening of the raw material after its peeling due to the action of oxidation-reducing enzymes. It also allows preserving L-ascorbic acid by 64.6 % and 65.0 % in the roots of celery and parsnip, respectively. The distribution of polyphenol oxidase activity in the celery and parsnip root crop is analyzed. The results of the work can be used in preparation of dishes with the use of white roots in restaurants in order to improve technological techniques during processing of raw materials into finished products, improve its quality, and preserve L-ascorbic acid, as well as expand the range of culinary products based on spicy aromatic raw materials.


2014 ◽  
Vol 5 (2) ◽  
pp. 473
Author(s):  
Engelwati Gani

A problem in accounting information systems of expenditure cash cycle in PT NR is estimated purchase raw materials often left over and valuable. To overcome it, accounting information with computer-based systems was designed related to raw material purchase that is expected to speed up procurement process and avoid fraud and error. The system processes waste materials that will be stored and used properly, so as to increase efficiency in purchasing raw materials. The analysis used for the construction of this system was business process analysis, problem identification, and analysis of information needs. The result achieved is accounting information systems of expenditure cash cycle to overcome the problem existing in the company. Research concludes the use of information systems can speed up purchase process and avoid fraud. Raw material management with system will make it easier to perform the calculation of actual costs and improve internal control.


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