Enhanced formation of magnesium silica hydrates (M-S-H) using sodium metasilicate and caustic magnesia in magnesia castables

A new procedure has been developed, which is based on homogeneous precipitation of organized mesoporous silica from an aqueous solution of sodium metasilicate and a nonionic poly(ethylene oxide) surfactant serving as a structure-directing agent. The decrease in pH, which induces the polycondensation of silica, is achieved by hydrolysis of ethyl acetate. Owing to the complexation of Na+ cations by poly(ethylene oxide) segments, assembling of the mesostructure appears to occur under electrostatic control by the S0Na+I- pathway, where S0 and I- are surfactant and inorganic species, respectively. As the complexation of Na+ cations causes extended conformation of poly(ethylene oxide) segments, the pore size and pore volume of organized mesoporous silica increase in comparison with materials prepared under neutral or acidic conditions. The assembling of particles can be fully separated from their solidification, which results in the formation of highly regular spherical particles of mesoporous silica.

Download Full-text

Struvite Grown in Gel, Its Crystal Structure at 90 K and Thermoanalytical Study

Crystals ◽

10.3390/cryst9020089 ◽

2019 ◽

Vol 9 (2) ◽

pp. 89 ◽

Cited By ~ 3

Author(s):

Jolanta Prywer ◽

Lesław Sieroń ◽

Agnieszka Czylkowska

Keyword(s):

Thermal Analysis ◽

Sodium Metasilicate ◽

X Ray Diffraction ◽

Gel Growth ◽

Growth Technique ◽

Thermoanalytical Study ◽

X Ray ◽

Cell Parameters ◽

Thermal Analysis Techniques ◽

Derivative Thermogravimetry

In this article, we report the crystallization of struvite in sodium metasilicate gel by single diffusion gel growth technique. The obtained crystals have a very rich morphology displaying 18 faces. In this study, the habit and morphology of the obtained struvite crystals are analyzed. The crystals were examined and identified as pure struvite by single X-ray diffraction (XRD). The orthorhombic polar noncentrosymmetric space group Pmn21 was identified. The structure of the crystal was determined at a temperature of 90 K. Our research indicates a lack of polymorphism, resulting from the temperature lowering to 90 K, which has not been previously reported. The determined unit cell parameters are as follows a = 6.9650(2) Å, b = 6.1165(2) Å, c = 11.2056(3) Å. The structure of struvite is presented here with a residual factor R1 = 1.2% at 0.80 Å resolution. We also present thermoanalytical study of struvite using thermal analysis techniques such as thermogravimetry (TG), derivative thermogravimetry (DTG) and differential thermal analysis (DTA).

Download Full-text

Sodium Metasilicate Cemented Analogue Material and Its Mechanical Properties

Advances in Materials Science and Engineering ◽

10.1155/2016/3716145 ◽

2016 ◽

Vol 2016 ◽

pp. 1-17 ◽

Cited By ~ 2

Author(s):

Songlin Yue ◽

Yanyu Qiu ◽

Pengxian Fan ◽

Pin Zhang ◽

Ning Zhang

Keyword(s):

Complex Geometry ◽

Sodium Metasilicate ◽

Raw Material ◽

Fine Aggregate ◽

Regression Equations ◽

Deformation And Failure ◽

Orthogonal Experiments ◽

Low Modulus ◽

New Type ◽

The Relationship

Analogue material with appropriate properties is of great importance to the reliability of geomechanical model test, which is one of the mostly used approaches in field of geotechnical research. In this paper, a new type of analogue material is developed, which is composed of coarse aggregate (quartz sand and/or barite sand), fine aggregate (barite powder), and cementitious material (anhydrous sodium silicate). The components of each raw material are the key influencing factors, which significantly affect the physical and mechanical parameters of analogue materials. In order to establish the relationship between parameters and factors, the material properties including density, Young’s modulus, uniaxial compressive strength, and tensile strength were investigated by a series of orthogonal experiments with hundreds of samples. By orthogonal regression analysis, the regression equations of each parameter were obtained based on experimental data, which can predict the properties of the developed analogue materials according to proportions. The experiments and applications indicate that sodium metasilicate cemented analogue material is a type of low-strength and low-modulus material with designable density, which is insensitive to humidity and temperature and satisfies mechanical scaling criteria for weak rock or soft geological materials. Moreover, the developed material can be easily cast into structures with complex geometry shapes and simulate the deformation and failure processes of prototype rocks.

Download Full-text

Waste-Based One-Part Alkali Activated Materials

Materials ◽

10.3390/ma14112911 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2911

Author(s):

Margarida Gonçalves ◽

Inês Silveirinha Vilarinho ◽

Marinélia Capela ◽

Ana Caetano ◽

Rui Miguel Novais ◽

...

Keyword(s):

Compressive Strength ◽

Microstructural Analysis ◽

Construction Materials ◽

Sodium Metasilicate ◽

High Compressive Strength ◽

Hardened State ◽

First Time ◽

Furnace Slag ◽

Alkali Activated

Ordinary Portland Cement is the most widely used binder in the construction sector; however, a very high carbon footprint is associated with its production process. Consequently, more sustainable alternative construction materials are being investigated, namely, one-part alkali activated materials (AAMs). In this work, waste-based one-part AAMs binders were developed using only a blast furnace slag, as the solid precursor, and sodium metasilicate, as the solid activator. For the first time, mortars in which the commercial sand was replaced by two exhausted sands from biomass boilers (CA and CT) were developed. Firstly, the characterization of the slag and sands (aggregates) was performed. After, the AAMs fresh and hardened state properties were evaluated, being the characterization complemented by FTIR and microstructural analysis. The binder and the mortars prepared with commercial sand presented high compressive strength values after 28 days of curing-56 MPa and 79 MPa, respectively. The mortars developed with exhausted sands exhibit outstanding compressive strength values, 86 and 70 MPa for CT and CA, respectively, and the other material’s properties were not affected. Consequently, this work proved that high compressive strength waste-based one-part AAMs mortars can be produced and that it is feasible to use another waste as aggregate in the mortar’s formulations: the exhausted sands from biomass boilers.

Download Full-text

A novel silicon complex is as effective as sodium metasilicate in enhancing the collagen-induced inflammatory response of silicon-deprived rats

Journal of Trace Elements in Medicine and Biology ◽

10.1016/j.jtemb.2007.11.004 ◽

2008 ◽

Vol 22 (1) ◽

pp. 39-49 ◽

Cited By ~ 8

Author(s):

Forrest H. Nielsen

Keyword(s):

Inflammatory Response ◽

Sodium Metasilicate

Download Full-text

Mechanical and Thermal Properties of Magnesia Binder Based on Natural and Technogenic Raw Materials

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.320.181 ◽

2021 ◽

Vol 320 ◽

pp. 181-185

Author(s):

Elvija Namsone ◽

Genadijs Sahmenko ◽

Irina Shvetsova ◽

Aleksandrs Korjakins

Keyword(s):

Thermal Conductivity ◽

Thermal Properties ◽

Raw Materials ◽

High Strength ◽

Strength Properties ◽

Waste Materials ◽

Mechanical And Thermal Properties ◽

Experimental Part ◽

Technogenic Raw Materials ◽

Caustic Magnesia

Because of low calcination temperature, magnesia binders are attributed as low-CO2 emission materials that can benefit the environment by reducing the energy consumption of building sector. Portland cement in different areas of construction can be replaced by magnesia binder which do not require autoclave treatment for hardening, it has low thermal conductivity and high strength properties. Magnesium-based materials are characterized by decorativeness and ecological compatibility.The experimental part of this research is based on the preparation of magnesia binders by adding raw materials and calcinated products and caustic magnesia. The aim of this study was to obtain low-CO2 emission and eco-friendly material using local dolomite waste materials, comparing physical, mechanical, thermal properties of magnesium binders.

Download Full-text

Final Report on the Safety Assessment of Potassium Silicate, Sodium Metasilicate, and Sodium Silicate1

International Journal of Toxicology ◽

10.1080/10915810590918643 ◽

2005 ◽

Vol 24 (1_suppl) ◽

pp. 103-117 ◽

Cited By ~ 4

Keyword(s):

Aqueous Solution ◽

Human Skin ◽

Sodium Silicate ◽

Safety Assessment ◽

Sodium Metasilicate ◽

Potassium Silicate ◽

Female Rats ◽

Male Rats ◽

Molar Ratio ◽

Eye Irritation

Potassium Silicate, Sodium Metasilicate, and Sodium Silicate combine metal cations with silica to form inorganic salts used as corrosion inhibitors in cosmetics. Sodium Metasilicate also functions as a chelating agent and Sodium Silicate as a buffering and pH adjuster. Sodium Metasilicate is currently used in 168 formulations at concentrations ranging from 13% to 18%. Sodium Silicate is currently used in 24 formulations at concentrations ranging from 0.3% to 55%. Potassium Silicate and Sodium Silicate have been reported as being used in industrial cleaners and detergents. Sodium Metasilicate is a GRAS (generally regarded as safe) food ingredient. Aqueous solutions of Sodium Silicate species are a part of a chemical continuum of silicates based on an equilibrium of alkali, water, and silica. pH determines the solubility of silica and, together with concentration, determines the degree of polymerization. Sodium Silicate administered orally is readily absorbed from the alimentary canal and excreted in the urine. The toxicity of these silicates has been related to the molar ratio of SiO2/Na2O and the concentration being used. The Sodium Metasilicate acute oral LD50 ranged from 847 mg/kg in male rats to 1349.3 mg/kg in female rats and from 770 mg/kg in female mice to 820 mg/kg in male mice. Gross lesions of variable severity were found in the oral cavity, pharynx, esophagus, stomach, larynx, lungs, and kidneys of dogs receiving 0.25 g/kg or more of a commercial detergent containing Sodium Metasilicate; similar lesions were also seen in pigs administered the same detergent and dose. Male rats orally administered 464 mg/kg of a 20% solution containing either 2.0 or 2.4 to 1.0 ratio of sodium oxide showed no signs of toxicity, whereas doses of 1000 and 2150 mg/kg produced gasping, dypsnea, and acute depression. Dogs fed 2.4 g/kg/day of Sodium Silicate for 4 weeks had gross renal lesions but no impairment of renal function. Dermal irritation of Potassium Silicate, Sodium Metasilicate, and Sodium Silicate ranged from negligible to severe, depending on the species tested and the molar ratio and concentration tested. Sodium Metasilicate was negative in the local lymph node assay (LLNA), but a delayed-type hypersensitivity response was observed in mice. Potassium Silicate was nonirritating in two acute eye irritation studies in rabbits. Sodium Metasilicate (42.4% H20) was corrosive to the rabbit eye. Sodium Silicate was a severe eye irritant in some eye irritation studies, but was irritating or nonirritating in others. A skin freshener containing Sodium Silicate was nonirritating. Sodium Metasilicate was nonmutagenic in bacterial cells. Rats given Sodium Silicate (600 and 1200 ppm of added silica) in the drinking water in reproductive studies produced a reduced number of offspring: to 67% of controls at 600 ppm and to 80% of controls at 1200 ppm. Three adult rats injected intratesticularly and subcutaneously with 0.8 mM/kg of Sodium Silicate showed no morphological changes in the testes and no effect on the residual spermatozoa in the ductus deferens. Sodium Metasilicate (37% in a detergent) mixed with water was a severe skin irritant when tested on intact and abraded human skin, but 6%, 7%, and 13% Sodium Silicate were negligible skin irritants to intact and abraded human skin. Sodium Silicate (10% of a 40% aqueous solution) was negative in a repeat-insult predictive patch test in humans. The same aqueous solution of Sodium Silicate was considered a mild irritant under normal use conditions in a study of cumulative irritant properties. The Cosmetic Ingredient Review (CIR) Expert Panel recognized the irritation potential of these ingredients, especially in leave-on products. However, because these ingredients have limited dermal absorption and Sodium Metasilicate is a GRAS direct food substance, the Panel deemed the ingredients safe for use in cosmetic products in the practices of use and concentration described in this safety assessment, when formulated to avoid irritation.

Download Full-text

Effect of Tartaric Acid on Hydration of a Sodium-Metasilicate-Activated Blend of Calcium Aluminate Cement and Fly Ash F

Materials ◽

10.3390/ma9060422 ◽

2016 ◽

Vol 9 (6) ◽

pp. 422 ◽

Cited By ~ 10

Author(s):

Tatiana Pyatina ◽

Toshifumi Sugama ◽

Juhyuk Moon ◽

Simon James

Keyword(s):

Fly Ash ◽

Tartaric Acid ◽

Calcium Aluminate ◽

Sodium Metasilicate ◽

Calcium Aluminate Cement ◽

Aluminate Cement

Download Full-text

Study of Hydrogen Generation of Aluminum-Containing Compositions with Boric Acid

KnE Engineering ◽

10.18502/keg.v3i3.1622 ◽

2018 ◽

Vol 3 (3) ◽

pp. 230

Author(s):

Salakhova A.A. ◽

Suvorov V.A. ◽

Firsova A. I. ◽

Belozerov V.I. ◽

Milinchuk V.K.

Keyword(s):

Boric Acid ◽

Hydrogen Generation ◽

Sodium Metasilicate ◽

Chemical Processes ◽

System Management ◽

Control Rod ◽

Radiation Fields ◽

Fuel Elements ◽

And Control ◽

Kinetics Of

The results of investigations of the kinetics of hydrogen generation compositions with aluminum, chemical activators (hydrated sodium metasilicate, oxide and calcium hydroxide) boric acid. Aluminium and its alloys used for the manufacture of protective sheaths of fuel elements and control rod protection system management, pipelines, tanks, and various support structures in the active zone of atomic reactors RBMK, research water-cooled reactors. The aluminum is protected from direct contact with water and steam surface layer of metal oxide having a high corrosion resistance at high temperatures in powerful radiation fields. However, after removal or when the discontinuity of the oxide layer of activated metal efficiently decompose water to hydrogen. It is established that the hydrogen aluminum-containing compositions is dependent on the concentration of boric acid. The discovery of the involvement of boric acid in these reactions expands the ideas about regularities of chemical processes of formation of hydrogen flowing in the water coolant of VVER reactors with the participation of the corrective additives and impurities.

Download Full-text

PEAT-CONTAINING COMPOSITION CONTAINING MAGNESIA BINDER

IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA ◽

10.6060/ivkkt201861008.5729 ◽

2018 ◽

Vol 61 (8) ◽

pp. 81

Author(s):

Natalia A. Mitina ◽

Vasiliy A. Lotov ◽

Margarita A. Kovaleva ◽

Natali O. Kopanitsa

Keyword(s):

Water Resistance ◽

Vertical Direction ◽

Water Soluble ◽

Fluid Mixing ◽

Thin Plates ◽

Hydration Reaction ◽

Strength Parameters ◽

Hydrogen Carbonates ◽

Hardening Coefficient ◽

Caustic Magnesia

Based on the new hydraulic magnesia binder, the compositions of the peat-containing composite material have been proposed and investigated. Hydraulic magnesia binder is an astringent composition of hydration-reaction hardening, which consists of an active caustic magnesia powder and a mixing fluid. As the fluid mixing an aqueous solution of magnesium bicarbonate Mg(HCO3)2 with a concentration of 13 g/l was used. Hardening forms water-insoluble products - magnesium hydroxide Mg(OH)2 and magnesium bicarbonates of general formula MgCO3·zMg(OH)2·nH2O, which makes it possible to harden and used products based on such a binder as in the air, and in water. The use of peat as a filler of the developed compositions will make it possible to obtain lightweight waterproof materials and products of heat-insulating purpose. It has been shown that the peat-and-magnesian compositions of all compositions have a hydration hardening coefficient of more than 1.0, which indicates intensification of the hydration and hardening processes in water conditions in comparison with air and large strength parameters. Using XRD the phase composition of peat products and peat- magnesium hardening compositions was established. Thermal analysis showed the presence of magnesium hydrogencarbonates in samples of compositions that are in the form of slightly crystallized neoplasms. Investigations by electron microscopy confirmed the presence of hydrocarbons such as magnesium particles dipingite Mg5(CO3)4(OH)2·5H2O and hydromagnesite Mg5(CO3)4(OH)2·4H2O in the form of thin plates with the vertical direction of crystallization. Increased water resistance of compositions based on hydraulic magnesia binder with non-water-resistant filler peat is due to mineralization of peat particles due to their impregnation with a solution of magnesium bicarbonate and the formation of water-soluble magnesium hydrogen carbonates in the loose porous structure of peat.

Download Full-text