scholarly journals Tubular precipitation structures: materials synthesis under non-equilibrium conditions

2012 ◽  
Vol 370 (1969) ◽  
pp. 2848-2865 ◽  
Author(s):  
Rabih Makki ◽  
László Roszol ◽  
Jason J. Pagano ◽  
Oliver Steinbock
Keyword(s):  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Quantitative Prediction ◽  
Materials Synthesis ◽  
Buoyant Jet ◽  
Tube Radius ◽  
Equilibrium Conditions ◽  
Mechanical Devices ◽  
Inorganic Precipitation ◽  
Reactant Solution

Inorganic precipitation reactions are known to self-organize a variety of macroscopic structures, including hollow tubes. We discuss recent advances in this field with an emphasis on experiments similar to ‘silica gardens’. These reactions involve metal salts and sodium silicate solution. Reactions triggered from reagent-loaded microbeads can produce tubes with inner radii of down to 3 μm. Distinct wall morphologies are reported. For pump-driven injection, three qualitatively different growth regimes exist. In one of these regimes, tubes assemble around a buoyant jet of reactant solution, which allows the quantitative prediction of the tube radius. Additional topics include relaxation oscillations and the templating of tube growth with pinned gas bubble and mechanical devices. The tube materials and their nano-to-micro architectures are discussed for the cases of silica/Cu(OH) 2 and silica/Zn(OH) 2 /ZnO tubes. The latter case shows photocatalytic activity and photoluminescence.

scholarly journals Printability and Setting Time of CSA Cement with Na2SiO3 and Gypsum for Binder Jetting 3D Printing

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2811
Author(s):  
Okpin Na ◽  
Kangmin Kim ◽  
Hyunjoo Lee ◽  
Hyunseung Lee
Keyword(s):  
3D Printing ◽  
Sodium Silicate ◽  
Setting Time ◽  
Sodium Silicate Solution ◽  
Preliminary Test ◽  
Silicate Solution ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate ◽  
Parametric Studies ◽  
Binder Jetting

The purpose of this study is to optimize the composition of CSA (calcium sulfoaluminate) cement with sodium silicate (Na2SiO3) and gypsum for binder jetting 3D printing. The preliminary test was carried out with an applicator to decide the proper thickness of one layer before using the 3D printer. A liquid binder was then selected to maintain the shape of the particles. Based on the results, the optimal mixture of dry materials and a liquid activator was derived through various parametric studies. For dry materials, the optimum composition of CSA cement, gypsum, and sand was suggested, and the liquid activator made with sodium silicate solution and VMA (viscosity modified agent) were selected. The setting time with gypsum and sodium silicate was controlled within 30 s. In case of the delayed setting time and the rapid setting mixture, the jetting line was printed thicker or thinner and the accuracy of the printout was degraded. In order to adjust the viscosity of the liquid activator, 10% of the VMA was used in 35% of sodium silicate solution and the viscosity of 200–400 cP was suitable to be sprayed from the nozzle. With this optimal mixture, a prototype of atypical decorative wall was printed, and the compressive strength was measured at about 7 MPa.

scholarly journals Silica extraction from bauxite reaction residue and synthesis water glass

2021 ◽  
Vol 10 (1) ◽  
pp. 268-283
Author(s):  
Yunlong Zhao ◽  
Yajie Zheng ◽  
Hanbing He ◽  
Zhaoming Sun ◽  
An Li
Keyword(s):  
Sodium Silicate ◽  
Water Glass ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Hydrated Calcium Silicate ◽  
Precipitated Silica ◽  
Alumina Gel ◽  
Silica Alumina ◽  
Element Removal ◽  
Hydrated Calcium

Abstract Bauxite reaction residue (BRR) produced from the poly-aluminum chloride (PAC) coagulant industry is a solid acidic waste that is harmful to environment. A low temperature synthesis route to convert the waste into water glass was reported. Silica dissolution process was systematically studied, including the thermodynamic analysis and the influence of calcium and aluminum on the leaching of amorphous silica. Simulation studies have shown that calcium and aluminum combine with silicon to form hydrated calcium silicate, silica–alumina gel, and zeolite, respectively, thereby hindering the leaching of silica. Maximizing the removal of calcium, aluminum, and chlorine can effectively improve the leaching of silicon in the subsequent process, and corresponding element removal rates are 42.81%, 44.15%, and 96.94%, respectively. The removed material is not randomly discarded and is reused to prepare PAC. The silica extraction rate reached 81.45% under optimal conditions (NaOH; 3 mol L−1, L S−1; 5/1, 75°C, 2 h), and sodium silicate modulus (nSiO2:nNa2O) is 1.11. The results indicated that a large amount of silica was existed in amorphous form. Precipitated silica was obtained by acidifying sodium silicate solution at optimal pH 7.0. Moreover, sodium silicate (1.11) further synthesizes sodium silicate (modulus 3.27) by adding precipitated silica at 75°C.

A Study on a Green Route to Preparation of Silica Powders with Rice Husk Ash

2014 ◽  
Vol 1010-1012 ◽  
pp. 1015-1019
Author(s):  
Ze Xin Yang ◽  
Lin Dong ◽  
Meng Wang ◽  
Huan Li
Keyword(s):  
Sodium Bicarbonate ◽  
Sodium Silicate ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Sodium Hydroxide Solution ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Raw Material ◽  
Transmission Electron ◽  
Thermal Analyzer

The main purpose of this article is to develop an environmentally friendly and economically effective process to produce silica from rice husk ash. Sodium silicate solution was prepared by the reaction of rice husk ash and sodium hydroxide solution, and then the sodium silicate solution was used as the raw material for the preparation of silica with sodium bicarbonate. During the reaction, the by-product can be passed into CO2 to prepare sodium bicarbonate what can be reutilized. Experimental route achieved resource recycling and environment-friendly, low energy consumption, zero emissions and so on. Meanwhile the microstructures of the silica powders were characterized by Transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Thermo gravimetric/Differential thermal analyzer (TG-DTA).The purity of silicon was up to 99.43% and the particle size was 200-300nm.

scholarly journals Red Mud-Blast Furnace Slag-Based Alkali-Activated Materials

2021 ◽  
Vol 13 (20) ◽  
pp. 11298
Author(s):  
Alessio Occhicone ◽  
Mira Vukčević ◽  
Ivana Bosković ◽  
Claudio Ferone
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Red Mud ◽  
Blast Furnace Slag ◽  
Bauxite Residue ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Waste Products ◽  
Furnace Slag ◽  
Alkali Activated

The aluminum Bayer production process is widespread all over the world. One of the waste products of the Bayer process is a basic aluminosilicate bauxite residue called red mud. The aluminosilicate nature of red mud makes it suitable as a precursor for alkali-activated materials. In this work, red mud was mixed with different percentages of blast furnace slag and then activated by sodium silicate solution at different SiO2/Na2O ratios. Obtained samples were characterized by chemical–physical analyses and compressive strength determination. Very high values of compressive strength, up to 50 MPa, even for high percentage of red mud in the raw mixture (70 wt.% of RM in powder mixture), were obtained. In particular, the higher compressive strength was measured for cubic samples containing 50 wt.% of RM, which showed a value above 70 MPa. The obtained mixtures were characterized by no or scarce environmental impact and could be used in the construction industry as an alternative to cementitious and ceramic materials.

Consolidation mechanism of materials obtained from sodium silicate solution and silica-based aggregates

2011 ◽  
Vol 357 (15) ◽  
pp. 3013-3021 ◽  
Author(s):  
Séka Simplice Kouassi ◽  
Monique Tohoué Tognonvi ◽  
Julien Soro ◽  
Sylvie Rossignol
Keyword(s):  
Sodium Silicate ◽  
Sodium Silicate Solution ◽  
Silicate Solution

scholarly journals Pengaruh Keasaman Medium dan Imobilisasi Gugus Organik pada Karakter Silika Gel dari Abu Sekam Padi

2005 ◽  
Vol 8 (3) ◽  
pp. 74-80
Author(s):  
Sriyanti Sriyanti ◽  
Taslimah Taslimah ◽  
Nuryono Nuryono ◽  
Narsito Narsito
Keyword(s):  
Sodium Silicate ◽  
Silica Gel ◽  
Sodium Silicate Solution ◽  
Thiol Group ◽  
Silicate Solution ◽  
Rice Hull ◽  
Amino Group ◽  
Rice Hull Ash ◽  
Host Matrix ◽  
Medium Acidity

Silica gel is well known as a material that may be used as adsorbent, host matrix for catalyst, etc. Hence, synthesis of silica gel from rice hull ash has been done by evaluation of the effect of medium acidity and organic group immobilized in the snythesis of silica gel.Synthesis of silica gel was done by adding sodium silicate solution from rice hull ash to hydrochloric acid until pH 3, 5 and 7. Immobilization of thiol group and amino group in silica was done by adding 3-mercaptopropyltrimethoxysilane or 3-aminopropyl-trimethoxysilane to sodium silicate solution and hydrochloride acid solution until pH: 7. The products were characterized by X-ray deffractometer and FTIR Spectroscopy.Results showed that porousitas of silica increased with increasing medium acidity ( decreasing pH medium).Immobilization thiol or amino group in silica added a functional group on silica but did not destroy primary structure of silica gel.Key Words: Silica Gel, Rice Hull Ash, 3-mercaptopropyltrimethoxysilane, 3-aminopropyl-trimethoxysilane.

Оbtaining of Lightweight Geopolymer Using Ash from Thermal Power Plants

2014 ◽  
Vol 92 ◽  
pp. 68-73
Author(s):  
Yancho Hristov ◽  
Yordan Kostadinov ◽  
Plamen Pashev ◽  
Bogdan Bogdanov
Keyword(s):  
Water Absorption ◽  
Power Plants ◽  
Inorganic Material ◽  
Thermal Power ◽  
Lightweight Aggregate ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Thermal Power Plants ◽  
Geopolymer Concrete ◽  
Partition Walls

A lightweight inorganic polymer is obtained using by ash from thermal power plants and lightweight aggregate from perlite . This inorganic material is activated using small amounts of sodium hydroxide and sodium silicate solution. In addition, porosity and water absorption were determined. Results showed that the lightweight geopolymer blocks with satisfactory strength and density could be made. The 28-day compressive strength of 5.2–13.8 MPa, density of 1075–1345 kg/m3, water absorption of 10–28% and porosity of 15–32% obtained. It can be used as lightweight geopolymer concrete for partition walls.

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