China
Africa
Explore chapters and articles related to this topic
Auxiliary methods technology
Published in Emilio Bilotta, Renato Casale, Claudio Giulio di Prisco, Salvatore Miliziano, Daniele Peila, Andrea Pigorini, Enrico Maria Pizzarotti, Handbook on Tunnels and Underground Works, 2023
G. Cassani, M. Gatti, C.L. Zenti, V. Manassero, S. Pelizza, A. Pigorini
Part of the colloidal solutions are the silicate-based grouts, mixtures of sodium silicate and reagent, which change in viscosity over time to produce a gel (gelling process). Sodium silicate is an alkaline colloidal aqueous solution. Reagents may be inorganic (mineral) or organic; the latter ones were often used in the past, but nowadays, they are avoided for environmental reasons.
Powder Consolidation and Forming of Ceramics
Published in M. N. Rahaman, Ceramic Processing and Sintering, 2017
Sodium silicate is an inorganic binder that finds considerable use in the forming of some traditional ceramics whose properties are not deleteriously affected by Na and Si residues. The compositions used as a binder have a Na2O: SiO2 ratio in the range of ˜2 to 4. Hydrolysis leads to the formation of fine SiO2 particles that gel and form a strong bonding phase between the ceramic particles.
Alkaline activators
Published in Caijun Shi, Pavel V. Krivenko, Della Roy, Alkali-Activated Cements and Concretes, 2003
Caijun Shi, Pavel V. Krivenko, Della Roy
Sodium silicate is the generic name for a series of compounds with the formula Na2O⋅nSiO2. Theoretically, the ratio n can be any number. Sodium silicates with different n have different properties that may have many diversified industrial applications. Commercial liquid sodium silicates have a ratio from 1.60 to 3.85. Sodium silicate liquids outside the range have limited stability and are not practical. Sodium silicate was first discovered by Van Helmont in 1640 when he combined silica with an excess of alkali and got a liquid in damp places. Johann Nepomuk von Fuchs rediscovered it in 1818 during his experiments. He dissolved silica in caustic soda potash, observed the glass-like properties of the solution, and named it waterglass (Vail 1928). After some investigations, he proposed a variety of applications for the silicates such as glue, cements, paints, detergents, hardening agent for natural and artificial stones, etc. However, it did not become very popular until 1887 when W. Gossage & Sons of Windnes, England exhibited a soap which contained 30% of 20° Baume solution of sodium silicate.
Performance of a new ceramic microfiltration membrane based on kaolin in textile industry wastewater treatment
Published in Chemical Engineering Communications, 2019
Priyanka Saini, Vijaya Kumar Bulasara, Akepati S. Reddy
Kaolin, quartz, feldspar, pyrophyllite, sodium metasilicate, sodium carbonate, and boric acid (CDH Ltd., India) were used in the preparation of ceramic microfiltration membranes (purity >99.5%). The technical specifications of the major raw material (kaolin) are shown in Table S1 of Supplementary data. Quartz provides thermal stability and contributes to mechanical strength. Feldspar provides high hardness and pyrophylllite withstands high pressure in molding. Kaolin contributes to high refractory properties and low plasticity to the membrane. Molten sodium carbonate under sintering conditions reacts with silica and forms sodium silicate releasing CO2 gas. The vacant spaces created by the accumulation of powders and release of CO2 gas imparts porous structure to the membrane contributing to membrane porosity (Kaur et al., 2016b). Sodium metasilicate acts as binder and increases mechanical strength (Bulasara et al., 2011). Boric acid acts as colloidal agent for the raw material paste.
Renewable biofuel production from biomass: a review for biomass pelletization, characterization, and thermal conversion techniques
Published in International Journal of Green Energy, 2018
Manar Younis, Sabla Y. Alnouri, Belal J. Abu Tarboush, Mohammad N. Ahmad
Sodium silicate is a special binder that can either be used as a matrix, film or a chemical binder. In order to reach a decent pellet strength, agglomerated materials often use binders such as sodium silicate, which fit in those three different categories. For instance, sodium silicate can be used as matrix binder in the cement industry (Mike McDonald and Hamilton 2009). Sodium silicates which have 45–65% water by weight facilitate the formation of a strong, rigid, glassy film, which assists in enhancing pellet strength. The viscosity, concentration, temperature, film thickness, and relative humidity are all factors that contribute to the rate of drying of sodium silicates during pelletization. It is possible to enhance the penetration and the adhesive forces of soluble silicate through the use of surfactants/wetting agents. Such agents also help strengthen the bond between pellets, by moderately increasing their degree of dispersion over the pellet surface. Sodium silicate dispersion is usually larger when the molecules can penetrate through smaller openings, with the aid of reduced surface tension.
Blast furnace slag-based geopolymer mortars cured at different conditions: modeling and optimization of compressive strength
Published in European Journal of Environmental and Civil Engineering, 2021
The alkaline activator used was consisted of alkali silicate and hydroxide solutions. The hydroxide solution required for activation was prepared to a concentration of 12 M using sodium hydroxide (NaOH) flakes and distilled water. The alkali silicate used was sodium silicate (Na2SiO3). Typical sodium silicate solution was prepared by heating 600 g of sodium hydroxide in 1000 ml of distilled water. Once the sodium hydroxide is dissolved, 600 g of sodium silicate were added. The solution was heated between additions. The alkaline activator was prepared such as the mass ratio of sodium silicate/sodium hydroxide = 2.