Wollastonite as a Flux for Ceramics Bodies

2012 ◽  
Vol 727-728 ◽  
pp. 1016-1021 ◽  
Author(s):  
S.R. Bragança ◽  
H.C.M Lengler ◽  
Carlos Pérez Bergmann

Wollastonite is a calcium silicate mineral natural or synthetic. Commercial wollastonite starts to melt at about 1450°C and can not be considered a "flux" as alkali feldspar. For this function, it depends on the reaction with other raw materials. Faced with this, came the goal of this work which was to investigate the mechanism of action of wollastonite as a ceramic flux. The use of wollastonite in ceramic bodies was investigated by analysis of its reactivity with other materials such as quartz, kaolin, talc and feldspar. It was analyzed the technological properties of the final parts, especially in relation to the firing temperature, phase formation and technological properties (mechanical strength, porosity, etc.). The results of this characterization showed that the technical properties of the parts are developed according to commercial porcelain products.

2021 ◽  
Author(s):  
Maryam Achik ◽  
Boutaina Moumni ◽  
Hayat Benmoussa ◽  
Abdellah Oulmekki ◽  
Abdelhamid Touache ◽  
...  

This chapter deals with the study of the possibility of using yellow clay - which was only used in pottery so far- in the civil engineering field as building materials, especially in the field of fired bricks. With the aim to improve the technological properties of yellow clay based bricks, two wastes were used as secondary raw materials. The first one is a mineral waste - pyrrhotite ash - this waste was neither characterized nor valued before by any other author. While the second waste is an organic waste - cedar sawdust - which is from the artisanal sector. Clay bricks containing yellow clay and different content of wastes were prepared and tested to evaluate their technological properties: water absorption, bulk density, porosity and mechanical strength… The test results indicate that the addition of wastes to clay bricks improves their technological properties and highlights the possibility of wastes reuse in a safe and sustainable way.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2247
Author(s):  
Fernando da Silva Souza ◽  
José Maria Franco de Carvalho ◽  
Gabriela Grotti Silveira ◽  
Vitória Cordeiro Araújo ◽  
Ricardo André Fiorotti Peixoto

The lack of usable aggregates for civil construction in Rio Branco (capital of Acre, a Federal State in the Amazon region) makes the production and use of recycled aggregates from construction and demolition waste (CDW) an alternative of great interest. In this study, a comprehensive characterization of CDW collected from 24 construction sites of six building types and three different construction phases (structures, masonry, and finishing) was carried out. The fine and coarse recycled aggregates were produced and evaluated in 10 different compositions. The aggregates’ performance was evaluated in four mixtures designed for laying and coating mortars with a total replacement of conventional aggregates and a mixture designed for a C25 concrete with 50% and 100% replacement of conventional aggregates. CDW mortars showed lower densities and greater water retention, initial adhesion, and mechanical strength than conventional mortars. CDW concretes presented lower densities and greater resistance to chloride penetration than conventional concrete, with a small mechanical strength reduction. The recycled CDW aggregates proved to be technologically feasible for safe application in mortars and concrete; for this reason, it is believed that the alternative and proposed methodology is of great interest to the Amazonian construction industry, considering the high costs of raw materials and the need for defining and consolidating a sustainable development model for the Amazon region.


Author(s):  
А.Г. КРУЧИНИН ◽  
С.Н. ТУРОВСКАЯ ◽  
Е.Е. ИЛЛАРИОНОВА ◽  
А.В. БИГАЕВА

Потребность в увеличении количества и качества производимой молочной продукции стимулирует исследования, направленные на повышение эффективности переработки молочного сырья, что, в свою очередь, невозможно без изучения технологических свойств молока и функционально необходимых ингредиентов, применяемых в производстве различной молочной продукции. На основе научно-технической информации международных и российских баз данных, систематизированной в рамках изучаемой тематики, представлен обзор научных работ о коагулянтах белков молока различного происхождения, применяемых при кислотной, кислотно-сычужной и сычужной коагуляции. Установлено, что в российской и международной производственной практике востребованы коагулянты животного, микробного и рекомбинантного происхождения. Наибольшим спросом среди коагулянтов животного происхождения пользуется химозин, получаемый из желудков телят. Ферменты микробного и рекомбинантного происхождения отличаются более стабильным качеством и низкой стоимостью, но их производство, основанное на методах генной инженерии, вызывающих предубеждение у большинства потребителей, практически полностью сосредоточено за рубежом. При условии повышения лояльности потребителей ферменты рекомбинантного происхождения могут стать наиболее перспективными функциональными ингредиентами. Исследования потенциала различных протеолитических ферментов растительного происхождения выявили невысокий технологический эффект их применения. Рассмотренный материал позволяет прогнозировать перспективность научных исследований по выявлению механизмов коагуляции молока и новых эффективных и универсальных коагулянтов совокупно с селекционной практикой отбора животных, направленной на улучшение технологических свойств молочного сырья. The need to increase the quantity and quality of dairy products encourages research aimed at improving the efficiency of processing dairy raw materials, which, in turn, is impossible without studying the technological properties of milk and functionally necessary ingredients used in the production of various dairy products. On the basis of scientific and technical information from international and Russian data bases, systematized within the framework of the subject under study, a review of scientific works on milk protein coagulants of various origins used in acid, acid-rennet and rennet coagulation is presented. It is established that coagulants of animal, microbial and recombinant origin are in demand in the Russian and international production practice. The greatest demand among coagulants of animal origin is chymosin, obtained from the stomachs of calves. Microbial and recombinant enzymes are characterized by more stable quality and lower cost, but their production, based on genetic engineering methods that cause prejudice among most consumers, is almost entirely concentrated abroad. If consumer loyalty is increased, recombinant enzymes may become the most promising functional ingredients. Studies of the potential of various proteolytic enzymes of plant origin revealed a low technological effect of their use. The considered material allows us to predict the prospects of scientific research to identify the mechanisms of milk coagulation and new effective and universal coagulants together with the breeding practice of animal selection, aimed at improving the technological properties of dairy raw materials.


2021 ◽  
Vol 316 ◽  
pp. 1050-1054
Author(s):  
V.N. Zyryanova ◽  
E.V. Lytkina ◽  
A.P. Ochur-Ool

Increasing water resistance and mechanical strength of hardening magnesian binders’ products can be achieved by introducing microfillings into a hardening dispersed system. It is shown that serpentine provides an increase strength and water resistance in hydration and hardening process, being as a structure-forming component, it intensifies this process. It allows expanding the raw material base for the production of magnesia binders for construction purposes.


2021 ◽  
Vol 9 (16) ◽  
pp. 90-97
Author(s):  
Kateryna Danilova ◽  
◽  
Oksana Zavarzina ◽  

An actual problem of the alcohol industry development is the expansion of the raw material base through the use of new, cheaper types of carbohydrate sources. Recently, glucose-fructose syrup has been of increasing interest to producers of ethanol. Among the producers of craft drinks, in particular rum-based drinks, cane molasses is in increasing demand. The article presents the technological aspects of the fermentation process of nonconventional sugar-containing raw materials on the example of glucose-fructose syrup and cane molasses in ethanol by different yeast strains. It is determined that glucose-fructose syrup and cane molasses are raw materials depleted of nitrogen, phosphorus and growth substances necessary for the yeast activity. To improve the technological properties of raw materials in the molasses, nitrogen, phosphorus nutrition and corn extract as a growth substance shall be added to a mash. Glucose-fructose syrup is of pH 3.68 and of acidity 0.12, which negatively affects the fermentation. It is established that in order to create optimal living conditions for yeast, it is necessary to add substances to the glucose-fructose syrup that will contribute to the safety of development and prevent the pH 3.5. It was determined that the alcohol yield from 1 ton of glucose-fructose syrup is 31.0 dal, from 1 ton of cane molasses is 24.0 dal on the yeast 46ED and 22 dal on the TegaYeast without the use of growth substances and vitamins necessary for the reproduction of yeast biomass. Under conditions of improving the technological properties of the mash from the glucose-fructose syrup and cane molasses by adding biologically active substances promoting the synthesis of yeast biomass, the ethanol content in the fermented mashes increases up to 11.9 12% vol.


2020 ◽  
Vol 3 ◽  
pp. 38-48
Author(s):  
Victoriya Gnitsevych ◽  
Tatiana Yudina ◽  
Yuliia Honchar ◽  
Olena Vasylieva ◽  
Liudmyla Diachuk

This study developed a technology of low-lactose semi-finished products, based on fermented whey and pumpkin pulp puree, and offered a possibility of its use in the technology of structured culinary products. This research carried out the required substantiation of the methods of preliminary processing of raw materials, and studied the technological properties and structure of model compositions with their use. During the experiment, a number of studies were carried out, which substantiated the method and modes of condensation of whey, and provided a comparative analysis of the homogeneity of lactose-free and lactose-containing samples of whey under various modes of condensation. The study obtained the results of calculations of the equivalent diameter of the studied samples of lactose-containing and low-lactose whey, condensed by the contact method and in vacuum. It was found, that the structure is homogeneous at a number average crystal diameter of up to 5 μm. The restriction is valid for CLLWV with a calculated diameter of about 3.84 μm with a coefficient of variation of 1.35 % with an increase of 10,000 times. The study revealed the alternation of smooth and granular sections of the micron level (0.1 ... 5 μm) in the structure of the studied low-lactose semi-finished product with an increase of 300 times. It was determined, that the extremum of the differential curve of the particle size distribution of CLLWV corresponds to the number average crystal diameter of 3.84 μm. It was established, that the most homogeneous fractional composition is inherent in the studied sample of CLLWV, for which the values of fraction diameters are in the range from 1.46 μm to 4.96 μm. The optimal ratio of the components of the model CLLWV: FPPP system was determined as 70 % to 30 % respectively. With this composition, the model system is characterized by the formation of protein-pectin complexes, which is confirmed by microscopy with a magnification of 90 times


Author(s):  
E. Gotlib ◽  
Phuong Ha ◽  
A. Hasanova ◽  
E. Galimov

The extraction of natural wollastonite in the world is limited, so it is relevant to synthesize it on the basis of available calcium and silicon-containing raw materials, and it is promising to use rice husks as a source of silicon dioxide, as a waste of rice processing. Due to the needle shape of the particles, natural wollastonite increases the wear resistance of epoxy coatings, which arouses interest to study the influence of the phase composition and properties of synthetic wollastonite on this property. The calcium silicate synthesized by authors contains β-wollastonite, which is the target component. Its maximum content is achieved at a synthesis temperature not higher than 950 °C, approximately at the level of natural Mivall 10–97. Larnite is found as an impurity in the composition of synthetic wollastonite, it is an island silicate with a chain structure and therefore cannot provide such a modifying effect as fillers with anisodiametric particle shape. The nature of the particle size distribution curves of both natural and synthetic volastonite has two maxima, regardless of the filler synthesis temperature, with the exception of calcium silicate obtained at 900 °C, the particle distribution is narrower than in synthesized fillers, and they are smaller. The wear resistance of epoxy compositions, when filled with both natural and synthetic wollastonite, increases. The greatest increase in this indicator is achieved when using synthetic wollastonite, obtained at a ratio of calcium oxide and silicon dioxide 1: 1 and temperatures of 900-1000 °C. Thus, epoxy materials filled with both natural and synthetic wollastonium obtained at optimal ratios of the initial components and synthesis temperatures can be effectively and economically used as wear-resistant coatings.


Author(s):  
Борисов ◽  
Ivan Borisov ◽  
Гребенюк ◽  
Aleksandr Grebenyuk

The ability of the concurrence of ferrites calcium reaction sulphatization and calcium silicate sulfate building was identified by calculating. Possible ways of the calcium silicate sulfate building reaction were determined. The ways of calcium silicate sulfate building number lowering by preparation sulfoferrite clinker out of raw materials which contain silicon oxide high quantity.


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