scholarly journals RESEARCH OF THE POSSIBILITY OF REDUCING THE CIRCULATION OF SULFUR OXIDE IN THE PRODUCTION OF WHITE CEMENT

2021 ◽  
Vol 6 (7) ◽  
pp. 89-98
Author(s):  
A. Novosyolov ◽  
I. Olianina ◽  
I. Novoselova ◽  
Y. Vasina ◽  
Y. Ershova ◽  
...  
Keyword(s):  
Calcium Sulfate ◽  
Sodium Oxide ◽  
Molar Ratio ◽  
Oxide Content ◽  
Sulfur Oxide ◽  
White Cement ◽  
Alkali Oxides ◽  
Potassium Oxides ◽  
Alkaline Oxides

The article discusses the possibility of reducing the circulation of sulfur oxide in the production of white cement by introducing alkaline potassium oxides K2O and sodium Na2O. A decrease in the circulation of sulfur oxide SO3 is achieved by increasing its yield in the clinker by transferring SO3 from a more sublimated compound of calcium sulfate CaSO4 to less sublimated potassium sulfates K2SO4 and sodium Na2SO4. Potassium and sodium oxides are introduced in the composition of carbonates and feldspar. The amount of introduced alkali oxides is controlled by the molar ratio A/S between sulfur oxide SO3 and alkaline oxides K2O and Na2O. It is shown that with the same molar ratio between sulfur oxide and alkaline oxides, the amount of SO3 removed with clinker depends on the ratio between potassium and sodium oxides. The higher the sodium oxide content, the more sulfur oxide comes out with the clinker and less remains to circulate in the kiln. The sublimation of sulfur oxide decreases from 70.5% - without the introduction of alkaline oxides, to 38,5 % at the maximum A/S ratio with the addition of potassium and sodium oxides in a ratio of 80:20 %. When potassium and sodium oxides are added in a ratio of 20:80%, the sublimation of sulfur oxide is reduced to 7,7 % at the same A/S ratio.

scholarly journals Hydrothermally Assisted Fabrication of TiO2-Fe3O4 Composite Materials and Their Antibacterial Activity

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4715
Author(s):  
Adam Kubiak ◽  
Marta Kubacka ◽  
Elżbieta Gabała ◽  
Anna Dobrowolska ◽  
Karol Synoradzki ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Composite Materials ◽  
Bet Surface Area ◽  
Molar Ratio ◽  
Oxide Content ◽  
Gram Positive ◽  
Gram Negative ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Oxide Composites

The TiO2-Fe3O4 composite materials were fabricated via the hydrothermal-assisted technique. It was determined how the molar ratio of TiO2 to Fe3O4 influences the crystalline structure and morphology of the synthesized composite materials. The effect of the molar ratio of components on the antibacterial activity was also analyzed. On the basis of XRD patterns for the obtained titanium(IV) oxide-iron(II, III) oxide composites, the two separate crystalline forms—anatase and magnetite —were observed. Transmission electron microscopy revealed particles of cubic and tetragonal shape for TiO2 and spherical for Fe3O4. The results of low-temperature nitrogen sorption analysis indicated that an increase in the iron(II, III) oxide content leads to a decrease in the BET surface area. Moreover, the superparamagnetic properties of titanium(IV) oxide-iron(II, III) oxide composites should be noted. An important aim of the work was to determine the antibacterial activity of selected TiO2-Fe3O4 materials. For this purpose, two representative strains of bacteria, the Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, were used. The titanium(IV) oxide-iron(II, III) oxide composites demonstrated a large zone of growth inhibition for both Gram-positive and Gram-negative bacteria. Moreover, it was found that the analyzed materials can be reused as antibacterial agents in three consecutive cycles with good results.

Characterization of Portuguese gypsums as raw materials for dermocosmetics

Clay Minerals ◽  
2019 ◽  
Vol 54 (3) ◽  
pp. 277-281 ◽  
Author(s):  
Cristiana Costa ◽  
António Fortes ◽  
Fernando Rocha ◽  
Angela Cerqueira ◽  
Delfim Santos ◽  
...  
Keyword(s):  
Calcium Sulfate ◽  
Raw Materials ◽  
Cement Industry ◽  
Oil Absorption ◽  
Chemical Quality ◽  
X Ray Diffraction ◽  
X Ray ◽  
White Cement ◽  
Wet Sieving

AbstractPortuguese gypsum deposits utilized by the cement industry were characterized mineralogically, chemically and technologically for possible application in dermocosmetics. The deposits studied (Loulé, Óbidos and Soure) correspond to small outcrops in diapiric anticline areas. In principle, they represent gypsites which are white, and generally of higher quality for traditional applications (e.g. white cement), or greyish, and generally not adequate for cements and mortars. The analytical methods used to characterize the materials were wet sieving and X-ray sedimentation, X-ray diffraction, X-ray fluorescence spectrometry and assessment of abrasiveness, plasticity, texturometrics (adhesivity and firmness), oil absorption and cooling rate. The Óbidos gypsum displayed greater mineralogical and chemical quality (almost pure calcium sulfate) and had a finer grain size (<63 μm), whereas Loulé and Soure gypsums contain mineralogical impurities (mainly quartz). The Óbidos gypsum shows good characteristics in general for application in dermocosmetics because of its absorption, plasticity, adhesivity, firmness and low abrasiveness.

scholarly journals Effect of sodium oxide content on the formation of nanogratings in germanate glass by a femtosecond laser

2018 ◽  
Vol 26 (10) ◽  
pp. 12761 ◽  
Author(s):  
Juechen Wang ◽  
Xiaofeng Liu ◽  
Ye Dai ◽  
Zhiyu Wang ◽  
Jianrong Qiu
Keyword(s):  
Femtosecond Laser ◽  
Sodium Oxide ◽  
Oxide Content ◽  
Germanate Glass

Study on the Preparation of Calcium Sulfate Whisker by Hydrothermal Method

2012 ◽  
Vol 602-604 ◽  
pp. 1369-1372 ◽  
Author(s):  
Kang Bi Luo ◽  
Hu Ping Li ◽  
Yan Xia Tan
Keyword(s):  
Hydrothermal Method ◽  
Calcium Chloride ◽  
Sodium Sulfate ◽  
Calcium Sulfate ◽  
Sulfate Solution ◽  
Solution Concentration ◽  
Raw Material ◽  
Molar Ratio ◽  
Feed Mode ◽  
Calcium Sulfate Whiskers

This article took the sodium sulfate and calcium chloride as the raw material and prepared calcium sulfate whiskers by hydrothermal method. The experimental results show that the calcium sulfate precursors are prepared by the reverse feed mode in which the sodium sulfate solution drop into the calcium chloride solution under the solution concentration 0.6 mol/L and the molar ratio of Na2SO4 to CaCl2 at 1:1.8. The precursors were placed in pH=6.12 hydrothermal environments and treated in the autoclave at 140 °C for 4 h to obtain the calcium sulfate whiskers having for the ratio of length to diameter at 97.5 and the better morphology.

Physical and optical properties of calcium sulfate ultra-phosphate glass-doped Er2O3

2018 ◽  
Vol 32 (08) ◽  
pp. 1850084
Author(s):  
Aliyu Mohammed Aliyu ◽  
R. Hussin ◽  
Karim Deraman ◽  
N. E. Ahmad ◽  
Amina M. Danmadami ◽  
...  
Keyword(s):  
Optical Properties ◽  
Molar Volume ◽  
Phosphate Glass ◽  
Calcium Sulfate ◽  
Optical Measurement ◽  
Emission Spectra ◽  
Optical Bandgap ◽  
Oxide Content ◽  
X Ray Diffraction ◽  
Xrd Techniques

The influence of erbium on physical and optical properties of calcium sulfate ultra-phosphate glass was investigated using conventional melt quench process. Selected samples of composition 20CaSO4 (80 – x) P2O5– xEr2O3 with 0.1 [Formula: see text]x [Formula: see text] 0.9 mol.% were prepared and assessed. X-ray diffraction (XRD) techniques were used to confirm the amorphous nature of the said samples. The structural units of phosphate-based glass were assessed from Raman spectra as ultra-(Q3), meta-(Q2), pyro-(Q1) and orthophosphate (Q0) units. Depolymerization process of the glasses was testified for higher calcium oxide content and UV-visible for optical measurement. Thermal analysis have been investigated by means of thermogravimetric analysis. The results show the decomposition of materials in the temperature range of 25[Formula: see text]C–1000[Formula: see text]C. Er[Formula: see text] absorption spectra were measured in the range of 400–1800[Formula: see text]nm. PL measurement was carried out in order to obtain the excitation and emission spectra of the samples. The emission spectra excited at 779[Formula: see text]nm comprises of 518[Formula: see text]nm, 550[Formula: see text]nm and 649[Formula: see text]nm of transition 4F[Formula: see text], 4S[Formula: see text] and 2H[Formula: see text] excited states to 4I[Formula: see text] ground state. In physical properties, the density calculated using Archimedes method is inversely proportional to molar volume with increase in Er[Formula: see text] ions. Optical bandgap (E[Formula: see text]) were determined using Tauc’s plots for direct transitions where E[Formula: see text] (direct) decreases with increase in erbium content. The refractive index increases with decreasing molar volume; this may have a tendency for larger optical bandgap. The result obtained from the glass matrix indicates that erbium oxide-doped calcium sulfate ultra-phosphate may give important information for wider development of functional glasses.

Intermediate Range Order in Sodium Tellurite Glasses

1996 ◽  
Vol 455 ◽  
Author(s):  
J. W. Zwanziger ◽  
J. C. McLaughlin ◽  
S. L. Tagg
Keyword(s):  
Random Model ◽  
Range Order ◽  
Sodium Oxide ◽  
Oxide Content ◽  
Tellurite Glasses ◽  
Sodium Ions ◽  
Distance Distributions ◽  
Sodium Tellurite ◽  
Maximum Stability ◽  
Spin Echoes

ABSTRACTInformation about the spatial distribution of sodium cations in sodium tellurite glasses is obtained from the decay rate of sodium spin echoes. The spin echoes decay due to the magnetic dipole coupling between sodium nuclei, with each pair contributing to the rate in proportion to 1/r6, where r is the distance between the pair. The experiment is used to probe the sodium distributions in sodium tellurite glasses as a function of sodium oxide content, and the resulting distance distributions are interpreted by comparison with model distributions. At low sodium contents the distribution is similar to that of a random model in which the sodium ions are constrained to be no closer than a minimum cut-off distance. At higher contents the distributions deviate significantly from the random model, suggesting the onset of medium range order in the distribution of sodium ions. This order is most pronounced at 20% sodium oxide content, the composition at which this glass has been claimed to have maximum stability against devitrification.

scholarly journals Quantitative in Situ X-ray Diffraction Analysis of Early Hydration of Belite-Calcium Sulfoaluminate Cement at Various Defined Temperatures

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 297
Author(s):  
Maruša Borštnar ◽  
Christian L. Lengauer ◽  
Sabina Dolenec
Keyword(s):  
Calcium Sulfate ◽  
Elevated Temperatures ◽  
Cement Clinker ◽  
Molar Ratio ◽  
Phase Assemblage ◽  
Early Hydration ◽  
X Ray ◽  
Calcium Sulfoaluminate ◽  
Molar Ratios

The influence of temperature on the early hydration of belite-calcium sulfoaluminate cements with two different calcium sulfate to calcium sulfoaluminate molar ratios was investigated. The phase composition and phase assemblage development of cements prepared using molar ratios of 1 and 2.5 were studied at 25, 40 and 60 °C by in situ X-ray powder diffraction. The Rietveld refinement method was used for quantification. The degree of hydration after 24 h was highest at ambient temperatures, but early hydration was significantly accelerated at elevated temperatures. These differences were more noticeable when we increased the temperature from 25 °C to 40 °C, than it was increased from 40 °C to 60 °C. The amount of calcium sulfate added controls the amount of the precipitated ettringite, namely, the amount of ettringite increased in the cement with a higher molar ratio. The results showed that temperature also affects full width at half maximum of ettringite peaks, which indicates a decrease in crystallite size of ettringite at elevated temperatures due to faster precipitation of ettringite. When using a calcium sulfate to calcium sulfoaluminate molar ratio of 1, higher d-values of ettringite peaks were observed at elevated temperatures, suggesting that more ions were released from the cement clinker at elevated temperatures, allowing a higher ion uptake in the ettringite structure. At a molar ratio of 2.5, less clinker is available in the cement, therefore these differences were not observed.

scholarly journals PLASMOCHEMICAL MODIFICATION OF WALL BUILDING MATERIALS

2020 ◽  
pp. 11-18
Author(s):  
Vasiliy Bessmertnyy ◽  
O. Puchka ◽  
Diana Bondarenko ◽  
I. Antropova ◽  
Lyudmila Bragina
Keyword(s):  
Aluminum Oxide ◽  
Phase Transformations ◽  
Liquid Glass ◽  
Building Materials ◽  
Sodium Oxide ◽  
Liquid Sodium ◽  
High Alumina ◽  
Oxide Content ◽  
Layer By Layer ◽  
Decorative Coating

the aim of the work is to study the effect of a high-temperature plasma torch on the processes of phase transformations and layer-by-layer modification of the protective and decorative coating on concrete using as a filler a mixture of quartz sand and hollow glass microspheres. The main tasks included: investigation of the processes of evaporation and thermal diffusion of oxides of plasma-coated coatings; study of phase transformations in the melt and its subsequent crystallization in the process of rapid spontaneous cooling of the fused protective and decorative coating; study of the effect of sodium liquid glass on the processes of polymorphic transformations of alumina and the formation of micro-wicks due to the intense diffusion of sodium oxide; study of operational characteristics of protective and decorative coatings. It was established that the initial phases in the protective-decorative coating are α-Al2O3 and CaO∙6Al2O3 (β-Al2O3), and the liquid sodium glass in the coating leads additionally to the formation of Na2O∙11Al2O3. The top layer of the protective and decorative coating is Na–Ca–Al–Si glass with regions of heterogeneities containing an increased content of sodium oxide. The content of aluminum oxide in the protective and decorative coating based on the battle of high-alumina refractory was 95.1 %. The introduction into the coating composition of sodium liquid glass minimizes the processes of dehydration of the binding component and changes the chemical composition of the protective and decorative coating. Reduction of the aluminum oxide content to 83.0 % affects the microhardness indicators. Microhardness of the concrete surface due to the introduction of liquid glass is reduced from 2510 HV to 887 HV.

scholarly journals INVESTIGATION OF THE POSSIBILITY OF REDUCING THE CIRCULATION OF VOLATILE COMPOUNDS IN A ROTARY KILN OF A DRY PRODUCTION METHOD

2020 ◽  
pp. 84-92
Author(s):  
A. Novoselov ◽  
Yu. Vasina ◽  
I. Novoselova ◽  
D. Goriaynova ◽  
Yu. Ershova
Keyword(s):  
Volatile Compounds ◽  
Rotary Kiln ◽  
Potassium Carbonate ◽  
Coming Out ◽  
Initial Period ◽  
Setting Time ◽  
Production Method ◽  
Molar Ratio ◽  
Sulfur Oxide ◽  
Firing System

The article considers a method of reducing the circulation of volatile compounds – sulfur, potassium, sodium compounds that can accumulate in the clinker burning system, circulate and lead to the formation of growths and deposits in the calciner, preheater and the loading part of the rotary kiln. The number of circulating compounds in the rotary kiln can be reduced by decreasing their degree of sublimation by converting them to less volatile compounds and removing these compounds from the firing system together with the clinker. In this case, it is necessary to provide a certain molar ratio between alkaline compounds and sulfur oxide, which depends on which compound will leave the burning system together with clinker. The introduction of potassium carbonate reduces the sublimation of sulfur oxide by 16 %, and sodium carbonate-by 45 %, due to the transfer of carbonates to less sublimable sulfates. The change of cement properties – setting time and strength, under the influence of compounds coming out with the clinker is shown. The start of setting of the cement paste is reduced by 41 %, the end of setting by 26 % with an increase in the ratio between alkaline compounds and sulfur oxide. The strength of cement in the initial period of hardening increases, and at the age of 28 days – decreases.

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