Synthesis of Calcium Hydrosilicates by the Hydrothermal Desiliconization of Quartz–Titanium Concentrates Followed by Wollastonite Crystallization

2021 ◽  
Vol 2021 (11) ◽  
pp. 1381-1386
Author(s):  
Yu. V. Zablotskaya ◽  
G. B. Sadykhov ◽  
T. V. Olyunina ◽  
A. S. Tuzhilin
Keyword(s):  
Calcium Hydrosilicates

scholarly journals THE EFFECT OF SODIUM SILICATE AND ITS SOLUTION ON THE PROPERTIES OF REFRACTORY COMPLEX BINDER/NATRIO SILIKATO KIEKIO IR JO TIRPALO TANKIO ĮTAKA KOMPLEKSINIO KAITRAI ATSPARAUS RIŠIKLIO SAVYBĖMS

1999 ◽  
Vol 5 (3) ◽  
pp. 211-216
Author(s):  
Valentin Antonovič ◽  
Stasys Goberis ◽  
Romualdas Mačiulaitis
Keyword(s):  
Sodium Silicate ◽  
Liquid Glass ◽  
Solid Phase ◽  
Physical And Mechanical Properties ◽  
Alumina Cement ◽  
Hardening Mechanism ◽  
Temperature Range ◽  
Calcium Hydrosilicates ◽  
Higher Temperature ◽  
Complex Binder

In order to improve thermal and mechanical characteristics of a traditional binder with liquid glass a complex binder consisting of liquid glass, its hardener and alumina cement (“Gorkal 70” containing not less than 70 per cent of AI2O3) was tested. Sodium silicate and its solution effect on physical and mechanical properties of a new refractory complex binder (Table 1, Fig 2) were investigated. The results obtained show that compressive strength of binding compound with high quantity of sodium silicate (N3) is the lowest after it had been cured, dried and fired at 300–600°C (Fig 3). It was also found that the strength of a complex binder with small quantity of sodium silicate (N1) in the temperature range of 20–600°C is 2–3 times as high as that of a traditional binder with dispersed fire-clay. The study in the formation of the structure of a complex binders dilatometric tests have also been made. After initial heating at 80–500°C the compositions contracted (Fig 4) due to dehidratation. At the temperature range of 580–750°C the contraction of compositions continue due to reactions at the solid phase. The hypothesis of the hardening mechanism in the complex binder was proposed. Liquid glass tends to restrain the hydration of the alumina cement though hardeners and sodium silicate interaction result in the intense formation of sodium calcium hydrosilicates. Therefore, a complex binder contains less sodium silicate than a traditional one while being used at higher temperature.

scholarly journals Chemo-mechanical characterization of hydrated calcium-hydrosilicates with coupled Raman- and nanoindentation measurements

2020 ◽  
Vol 118 ◽  
pp. 104582 ◽  
Author(s):  
P. Stemmermann ◽  
K. Garbev ◽  
B. Gasharova ◽  
G. Beuchle ◽  
M. Haist ◽  
...  
Keyword(s):  
Mechanical Characterization ◽  
Calcium Hydrosilicates ◽  
Hydrated Calcium

Fine-Grained Concrete with Nanodispersed Silica Additive

2020 ◽  
Vol 992 ◽  
pp. 156-161
Author(s):  
N.P. Lukuttsova ◽  
E.G. Borovik ◽  
D.A. Pehenko
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Pore Diameter ◽  
Fine Grained ◽  
Silica Concentration ◽  
Calcium Hydrosilicates ◽  
Additive Particle ◽  
Nanodispersed Silica ◽  
Silica Additive ◽  
Number Of Particles

The effect of the modifying nanodispersed silica (NS) additive, obtained by the polycondensation method, on the properties of fine-grained concrete (FGC) is studied. It is revealed that the dependence of the NS-additive particle size on its age is extreme. The maximum number of particles of up to 100 nm in the additive is observed at the age of 10 days, and then their number decreases. However, it affects the FGC strength little even after 30 days of the additive storage. It is established that the NS-additive could be most effectively used with 0.23% of an active silica concentration and pH 4.1 in combination with S-3. At that, the porosity declines from 17.5 to 12.9% and the pore diameter diminishes from 3.171 to 0.689 μm. It leads to an increase in the compressive strength by 2 times and a decrease in water absorption by 1.6 times as compared to the control composition without additives. An increase in the frost resistance of the modified fine-grained concrete to F250 is recorded; it occurs due to a decrease in porosity at portlandite binding with amorphous silica additives into low-basic calcium hydrosilicates.

The Increase of Hydration Activity of Portland Cement by Additives of Crystalline Hydrates

2019 ◽  
Vol 974 ◽  
pp. 195-200
Author(s):  
Yury R. Krivoborodov ◽  
Svetlana V. Samchenko
Keyword(s):  
Phase Composition ◽  
Portland Cement ◽  
Cement Hydration ◽  
Bound Water ◽  
Cement Stone ◽  
Pulsation Apparatus ◽  
Rotary Pulsation Apparatus ◽  
Calcium Hydrosilicates ◽  
Crystalline Hydrates

The article presents the results of a study of the effect of synthesized microdisperse additives of crystalline hydrates based on calcium sulfoaluminates on the properties of cement stone. The effectiveness of the use of a rotary pulsation apparatus (RPA) to obtain microdispersed additives is identified. The possibility of accelerating the hardening of cement stone by entering microdispersed additives into its composition is shown. It has been established that in the presence of microdispersed additives of crystalline hydrates in the cement stone, the phase composition of hydrate tumors changes, the amount of calcium hydrosilicates and ettringite increases, the porosity decreases and the strength of the cement stone increases. This provision is confirmed by the increase in the degree of cement hydration, the amount of bound water in all periods of hardening of the stone. It is proposed to use microdisperse additives, which play the role of primers for the crystallization of ettringite and calcium hydrosilicates, to increase the strength of cement stone in the early stages of hardening.

Properties of Composite Gypsum Binders Depending on Multicomponent Mineral Additives

2019 ◽  
Vol 945 ◽  
pp. 238-243 ◽  
Author(s):  
Valery S. Lesovik ◽  
N.V. Chernysheva ◽  
M.Yu. Drebezgova
Keyword(s):  
Portland Cement ◽  
Magnetic Separation ◽  
Water Resistance ◽  
Cement Hydration ◽  
Raw Materials ◽  
Crystal Formation ◽  
Calcium Hydrosilicates ◽  
Nanodispersed Silica ◽  
Mineral Additives ◽  
Ferruginous Quartzites

This article considers the possibility of increasing the effectiveness of composite gypsum binders (CGB) by controlling the processes of structure formation as a result of using new types of multicomponent mineral additives that are significantly different from the traditionally used quartz raw materials:- waste of wet magnetic separation of ferrous quartzites (WMS waste,) of polymineral composition with quartzy of varying degrees of crystallinity, nanodispersed silica and chalk powder. We have studied the cause-effect relationship between the change in the ratio of binding and mineral additives of various compositions, which determines the conditions for the formation of technological and strength characteristics of the projected composite materials with specified performance properties. We have established the presence of regularities in the changes in the properties of CGB, the composition of the hardening products and the microstructure depending on the type and content of gypsum binders of β-and α-modifications, portland cement, multicomponent finely-dispersed mineral additives, the regularity consists in the binding of portlandite, which is released upon portland cement hydration, by the amorphous phase of earth siliconas a part ofnanodispersed powder and chalcedony variety of quartz waste of wet magnetic separation of ferruginous quartzites. This provides a reduction in the basicity of the solidifying system, the intensification of crystal formation, and the formation of newgrowths with a high content of tobormorite-low-basic calcium hydrosilicates that compact the microstructure of the hardening matrix and, as a result, increase the water resistance and stability. It is noted that this mechanism of hydration of CGB minimizes inner stresses and volume deformations, therefore the number of microcracks decreases, which leads to an increase in its efficiency in comparison with the traditionally used gypsum binder and that differs from the traditional portland cement by a fast strength generation.

The Economic Efficiency of the Development of Dry Mixes with the Supplement Based on Calcium Hydrosilicates

2020 ◽  
Vol 299 ◽  
pp. 216-220
Author(s):  
Irina Sergeevna Pyshkina ◽  
K.V. Zhegera
Keyword(s):  
High Activity ◽  
Economic Efficiency ◽  
Calcium Hydrosilicates ◽  
Calcium Hydrosilicate

Provides information about the effectiveness of the introduction of modifying supplement in the formulation of dry mixes. Presents information about the technology of synthesis of supplement based on calcium hydrosilicates. It is established that the supplement has a high activity. A recipe for a lime dry mixes is presented using a supplement based on calcium hydrosilicate, synthesized in the presence of diatomite. The economic efficiency of the developed dry mixes with the use of calcium hydrosilicates has been calculated.

Content of Aluminium Hydroxide in Lime-Silica Composite and its Influence on Tobermorite Formation

2018 ◽  
Vol 916 ◽  
pp. 195-199 ◽  
Author(s):  
Jindrich Melichar ◽  
Vit Cerný ◽  
Jan Fleischhacker ◽  
Rostislav Drochytka
Keyword(s):  
Mechanical Properties ◽  
Aluminium Hydroxide ◽  
Raw Materials ◽  
Mineralogical Composition ◽  
Silica Sand ◽  
Chemical Formula ◽  
Hydrothermal Conditions ◽  
Silicon Oxides ◽  
Calcium Hydrosilicates ◽  
Aerated Concrete

Aerated concrete is lightweight building material with excellent thermos-technical properties compared to its strengths, easy workability and economic efficiency. It is material with long tradition of manufacturing since 1924 but its potential is yet possible to be extended. Since the beginning pure ingredients such as lime and silica sand has been used. Nowadays we are looking for ways to replace these expensive raw materials with cheaper alternatives. One of the most important mechanical properties of each material is its strength. In case of aerated concrete the bearer of strength is mineral tobermorite. It is created by reaction of silicon oxides and lime at hydrothermal conditions. It belongs to the group of calcium hydrosilicates with chemical formula Ca5Si6O16(OH)2·4H2O. Main goal of this paper is proposal for modification of the raw materials composition and autoclave regime of aerated concrete using aluminium hydroxide in order to improve final mechanical properties and mineralogical composition.

scholarly journals X-ray diffraction of concrete composites of high structural strength and density

2021 ◽  
Vol 22 (4) ◽  
pp. 746-749
Author(s):  
Oleksandr Sumariuk ◽  
Ihor Fodchuk ◽  
Volodymyr Romankevych
Keyword(s):  
Compressive Strength ◽  
Structural Strength ◽  
Cement Stone ◽  
Qualitative Composition ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Factors Affecting ◽  
X Ray ◽  
Calcium Hydrosilicates ◽  
Main Factors

Аn analysis of the structure formation of concrete composites, compressive strength of which exceeds 120 MPa and a quantitative analysis of their qualitative composition and hydration products by X-ray diffraction, x-ray spectral analysis. The main factors affecting the physicomechanical parameters of the complex of various nanofillers and the formation of a denser cement stone structure, which mainly includes calcium hydrosilicates, calcium silicate hydroaluminates and hydroaluminates of various basicity, are studied.

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