scholarly journals Mechanism of gypsum hardening

2018 ◽  
Vol 196 ◽  
pp. 04096 ◽  
Author(s):  
Victoria Petropavlovskaya ◽  
Tatiana Novichenkova ◽  
Andrey Pustovgar ◽  
Aleksandr Buryanov ◽  
Kirill Petropavlovskii
Keyword(s):  
Calcium Sulfate ◽  
Raw Material ◽  
Pilot Studies ◽  
Industry Waste ◽  
Calcium Sulfate Dihydrate ◽  
The Way

In the present work the receiving of gypsum products on the basis of a calcium sulfate dihydrate is described. As a raw material, the calcium sulfate dihydrate in the form of industry waste was used. This research offers the mechanism of un hydration hardening of monomineral bindings, including gypsum. The mechanism is based on interaction of particles of the different size in the conditions of supersaturation when pressing. Under the corresponding conditions in system of a dihydrate crystallizational contacts are formed. The offered mechanism is confirmed with pilot studies. Researches of solubility of powders, to deformations of raw mix, strength, density and other characteristics of structure are conducted. Strength reaches to 74 MPa. The way allows to simplify technology of receiving gypsum products. Expenses of energy decrease. Burn is excluded and the grinding is reduced. Thus the offered of un hydration hardening of monomineral binders has high innovative appeal.

Hyperpressed Calcium Sulfate Dihydrate Structure

2014 ◽  
Vol 1025-1026 ◽  
pp. 820-823 ◽  
Author(s):  
Victoria Petropavlovskaya ◽  
Аleksandr Buryanov ◽  
Тatyana Novichenkova
Keyword(s):  
Calcium Sulfate ◽  
Raw Materials ◽  
Disperse Systems ◽  
Calcium Sulfate Dihydrate ◽  
Ceramic Manufacture ◽  
The Way

In article the method of formation of structure of disperse systems on a basis of calcium sulfate dihydrate is described. It is based on various concentration of a solution at a surface of particles of the various size. As raw materials it was used calcium sulfate dihydrate − a withdrawal of ceramic manufacture. The picked up structure of particles in the sizes was applied. For acknowledgement of the offered method following researches have been carried out on: solubilities of powders, to deformations of a raw mix, durability of structure. The way of reception of gypsum products allows to simplify technology. Energy expenses decrease. Burning is excluded and the grinding is reduced.

Preparation of anhydrite from eggshell via pyrolysis

2018 ◽  
Vol 7 (2) ◽  
pp. 139-146 ◽  
Author(s):  
Nuchnapa Tangboriboon ◽  
Wanitcha Unjan ◽  
Watchara Sangwan ◽  
Anuvat Sirivat
Keyword(s):  
Calcium Sulfate ◽  
Pore Diameter ◽  
Raw Materials ◽  
Raw Material ◽  
X Ray ◽  
Anhydrous Calcium Sulfate ◽  
Calcium Sulfate Dihydrate ◽  
Thermal Analyzer ◽  
Infrared Spectrometer ◽  
Calcium Sulfate Hemihydrate

AbstractCalcium sulfate dihydrate (CaSO4·2H2O) was prepared from the chemical reaction between calcium carbonate from duck eggshell and sulfuric acid at 25°C. The CaSO4·2H2O was dried in an oven at 110°C and transformed into calcium sulfate hemihydrate or plaster of Paris (CaSO4·0.5H2O). The CaSO4·0.5H2O was calcined at 700, 800 and 900°C and transformed into anhydrite or anhydrous calcium sulfate (CaSO4). The raw material used in this research was the duck eggshell, the waste eggshell generated from food processing industries. The obtained anhydrous calcium sulfate or anhydrite has true density, color, specific surface area, pore diameter and particle size equal to 2.95 g/cm3, white powder, 3.57 m2/g, 96.98 Å and 3.983 μm, respectively. In addition, other characteristics, microstructures, phase transformation and physical properties of raw materials and calcium sulfates were investigated and reported here using X-ray fluorescencemeter, Fourier transform infrared spectrometer, differential thermal analyzer, thermogravimetric analysis, scanning electron microscope, X-ray diffractometer, pycnometer method and Brunauer-Emmett-Teller.

scholarly journals Influence of Activity of CaSO4·2H2O on Hydrothermal Formation of CaSO4·0.5H2O Whiskers

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
S. C. Hou ◽  
L. Xiang
Keyword(s):  
Specific Surface ◽  
Calcium Sulfate ◽  
Room Temperature ◽  
Raw Material ◽  
Particle Sizes ◽  
Grain Sizes ◽  
Surface Areas ◽  
Aspect Ratios ◽  
Calcium Sulfate Dihydrate ◽  
Specific Surface Areas

The influence of the activity of calcium sulfate dihydrate (CaSO4·2H2O) on the hydrothermal formation of CaSO4·0.5H2O whiskers was investigated in this paper, using commercial CaSO4·2H2O as the raw material. The experimental results indicated that the activity of CaSO4·2H2O was improved after calcination of the commercial CaSO4·2H2O at 150°C for 6.0 h followed by hydration at room temperature for 1.0 h, corresponding to the decrease of the agglomerated particle sizes from 29.7 μm to 15.1 μm, the increase of the specific surface areas (BET) from 4.75 m2·g−1to 19.12 m2·g−1and the grain sizes from 95 nm to 40 nm. The active CaSO4·2H2O produced by the calcination-hydration treatment favored the hydrothermal dissolution of CaSO4·2H2O, promoting the formation of hemihydrate calcium sulfate (CaSO4·0.5H2O) whiskers with high aspect ratios.

Life as a Raw Material: Illusions of Control

Somatechnics ◽  
2012 ◽  
Vol 2 (2) ◽  
pp. 250-262 ◽  
Author(s):  
Oron Catts ◽  
Ionat Zurr
Keyword(s):  
Synthetic Biology ◽  
Cognitive Engineering ◽  
Raw Material ◽  
Future Scenarios ◽  
Short History ◽  
Know How ◽  
Political Forces ◽  
History Of ◽  
The Way

The paper discusses and critiques the concept of the single engineering paradigm. This concepts allude to a future in which the control of matter and life, and life as matter, will be achieved by applying engineering principles; through nanotechnology, synthetic biology and, as some suggest, geo-engineering, cognitive engineering and neuro-engineering. We outline some issues in the short history of the field labelled as Synthetic Biology. Furthermore; we examine the way engineers, scientists, designers and artists are positioned and articulating the use of the tools of Synthetic Biology to expose some of the philosophical, ethical and political forces and considerations of today as well as some future scenarios. We suggest that one way to enable the possibilities of alternative frames of thought is to open up the know-how and the access to these technologies to other disciplines, including artistic.

Marl Clay Pottery Fabrics of the New Kingdom from Memphis, Saqqara and Amarna

1992 ◽  
Vol 78 (1) ◽  
pp. 29-91 ◽  
Author(s):  
J. D. Bourriau ◽  
P. T. Nicholson
Keyword(s):  
Ancient Egypt ◽  
Research Tool ◽  
Raw Material ◽  
Nile Valley ◽  
New Kingdom ◽  
Commodity Exchange ◽  
Thin Sections ◽  
Vienna System ◽  
The Way

This paper attempts to introduce a research tool essential for the study of production and trade and the way they were organized in ancient Egypt by examining marl clay pottery fabrics from the New Kingdom. Marl clay was the preferred raw material for the containers used in the transport of food within the Nile Valley and beyond. Sample sherds from Memphis, Saqqara and Amarna are described and illustrated macroscopically (20 × magnification) and microscopically (from thin sections). The results are used to create a concordance between the fabric classifications used at these sites, and with that used at Qantir and with the Vienna System. The data given will allow other archaeologists to link their own material to that described and so have access to the evidence this pottery provides on chronology and commodity exchange.

scholarly journals WOOD COMPONENTS AS SOURCES OF PENTO-CONTAINING RAW MATERIALS FOR SYNTHESIS OF USEFUL COMPOUNDS, PRODUCTS AND REAGENTS

2021 ◽  
Vol 64 (3) ◽  
pp. 107-115
Author(s):  
Irina A. Chetvertneva ◽  
Oleg Kh. Karimov ◽  
Galina A. Teptereva ◽  
Natalia S. Tivas ◽  
Eldar M. Movsumzade ◽  
...  
Keyword(s):  
Raw Materials ◽  
Condensation Reaction ◽  
Agricultural Waste ◽  
Monomer Unit ◽  
Paper Industry ◽  
Raw Material ◽  
Chemical Transformations ◽  
Covalent Bonds ◽  
Industry Waste ◽  
Wood Processing

The paper considers the main components and products of wood processing, agricultural waste, pulp and paper industry waste and qualifies them as sources of pentose-containing resource-renewable domestic raw materials. The article describes in detail the structural components of wood as a natural polymer, which contains aromatic and carbohydrate parts. It is noted that these poly-mers are promising as raw materials for the production of useful chemical products. The role of lignin, cellolose and hemicellulose in the design of mechanical and structural properties of wood is considered. The article considers the features of the sulfonation reactions of the lignin monomer unit depending on the pH of the medium: acidic, neutral and alkaline. There are three main reac-tions that occur simultaneously with lignin in the process of wood delignification during sulfite cooking, such as the sulfonation reaction, the hydrolytic destruction reaction, and the condensation reaction. It is shown that the lignin-hemicellulose matrix contains three types of interconnected mesh structures: the lignin itself; a network of covalent bonds of lignin with hemicelluloses, and a network whose structure is obtained due to the hydrogen bond and the forces of the physical inter-action of lignin and hemicelluloses. The features of chemical transformations of the monomeric aromatic link of lignosulfonate – phenylpropane unit in the processes of wood delignification, the main chemical reactions of wood raw material delignification under the conditions of sulfite and neutral-sulfite brews are shown. The method of quantitative determination of monosaccharides in the composition of the carbohydrate part is proposed.

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