Showing papers on "Sodium silicate published in 2018"
TL;DR: In this paper, the core-shell structured magnetic support and so-prepared solid catalyst were characterized by various techniques, and the solid catalyst exhibited a strong magnetic response and displayed extraordinary catalytic activities in the transesterification of soybean oil for the production of biodiesel, with the oil conversion reaching 99.2% by using the methanol-to-oil molar ratio of 25:1 and catalyst loading of 3'wt% at reflux of methanoline after 8'h of reaction.
161 citations
TL;DR: In this paper, the compressive strengths and microstructures of geopolymer pastes containing waste glass powder and high-calcium fly ash were investigated, and the results indicated that waste glass powders could be used to replace fly ash to produce geopolymers with 7-d compressive strength of 34-48MPa.
156 citations
TL;DR: In this article, the effect of nano silica on the short term severe durability performance of fly ash based geopolymer concrete (GPC) specimens was investigated, and four types of GPC were produced with two types of low calcium fly ashes (FAI and FAII), and ordinary Portland cement concrete (OPC) concrete was also cast for reference.
143 citations
TL;DR: In this article, a low cost, low environmental impact sodium silicate solution (waterglass) from Rice Husk Ash (RHA) and more specifically RHA from Vietnam was developed.
121 citations
TL;DR: In this article, the structural buildability of layered objects and the influence of the layering process were assessed in terms of flexural strength through 3-point bending tests, and the results indicated that the lay-ering process has negative impact on the mechanical strength of build-up materials.
114 citations
TL;DR: In this paper, the influence of different alkaline activators (Na+ and K+) on the mechanical, thermal, and microstructural behaviors of metakaolin-based geopolymer mortars was investigated.
97 citations
TL;DR: In this article, the properties of lightweight high-calcium fly ash geopolymer concrete (LWGC) containing crushed clay brick and pumice aggregates were examined and compared with those of the normal density control geopolym concrete.
89 citations
TL;DR: In this article, three activating alkaline solutions were prepared from sodium hydroxide solution (8, 10 and 12 M) with sodium silicate (Na2SiO3) in order to obtain the sodium silicates solutions with moduli of SiO2/Na2O equal to 0.75, 0.92 and 1.04.
85 citations
TL;DR: In this article, the properties of geopolymer mortars (GPMs) prepared by combining agricultural and industrial wastes including granulated-blast-furnace-slag (GBFS), fly-ash (FA), and palm-oil-fuel-ashes (POFA) were examined.
84 citations
TL;DR: In this article, the compressive strength and micro-structural properties of the geopolymer pastes synthesized from different mass ratios of alkali to the mixed solids, i.e., Na2O content, and different molar ratios of SiO2 to Na 2O in the mixed alkaline solution (i.e. different moduli).
78 citations
TL;DR: In this article, after construction of metakaolin-based geopolymer concrete containing 03, 05 and 1% polypropylene (PP) fibers with monomer ratios of 2, 25 and 3, engineering properties including compressive strength, flexural strength, displacement, Si/Al ratio, water absorption and electrical resistivity were assessed via scanning electron microscopic (SEM) and X-ray Diffraction (XRD) tests.
TL;DR: In this article, strength and microstructural development of full (FT) and coarse sulphidic tailings (CT) cemented paste backfill (CPB) produced from sodium-silicate activated slag at different silicate modulus (Ms) were investigated in the short and long-term.
TL;DR: In this paper, the surface interactions and adsorption mechanism of alkyl hydroxamic acid bearing collectors and sodium silicate depressant on common carbonatite gangue minerals, including calcite, dolomite and ankerite in flotation were investigated.
TL;DR: In this paper, the compressive strength of fly ash based geopolymer mortar by varying the molarity of sodium hydroxide as 12, 14, M, 16, M and accompanying by sodium silicate in 2:1 (Na 2 SIO 3 ) in 2.
TL;DR: In this article, the depression mechanism of the depressed mixture of sodium silicate and Fe(II) was investigated using zeta potential measurements and X-ray photoelectron spectroscopy.
TL;DR: In this article, nano-SiO2 was proposed as a partial replacement to natural pozzolan (NP) in order to improve the reaction kinetics and subsequently, the mechanical strength of alkali activated concrete (AAC).
TL;DR: In this article, a ReaxFF reactive force field for Na/Si/O/H interactions is presented, which enables reactive molecular dynamics simulation of the sodium silicate-water interfaces.
Abstract: We present the development of a ReaxFF reactive force field for Na/Si/O/H interactions, which enables reactive molecular dynamics simulation of the sodium silicate–water interfaces. The force field parameters were fitted against various quantum mechanical calculations, including equations of state of different NaSiOx crystalline phases, energy barriers of a sodium cation’s transport within the sodium silicate crystal structure, interactions between the hydroxylated silica surface and sodium cation–water systems, and dissociation energies of [NaOH–n(H2O)] (n = 1–6) clusters. After the optimization process, we validated the force field capability through calculating the structures of sodium silicate crystals and glasses and transport properties of sodium ions and protons within the amorphous structures. The force field was also applied to validate the dissociation behavior of sodium hydroxides within the bulk water. Our results with the developed force field are relevant to detailed chemical dissolution mec...
TL;DR: In this paper, a self-compacting alkaline activated concrete (SCGC) was used to improve fresh properties and to control rapid setting 25% low calcium fly ash and 75% ground granulated blast furnace slag were used to produce SCGC.
Abstract: Geopolymer technology concentrates producing eco-friendly binder which can be a permanent solution for replacement of traditional hydraulic binders. The performance benefits and operational energy savings can be accomplished by use of self-compacting alkaline activated concrete commonly known as Self-Compacting Geopolymer Concrete (SCGC). The current study access experimental investigation on influence of different concentration of sodium hydroxide solution (2 M, 4 M, 6 M, 8 M, 10 M and 12 M) and alkaline activator ratio (2, 2.5, 3, 3.5 and 4) fresh properties, compressive strength and durability properties. The industrial by-products such as fly ash and Ground Granulated Blast furnace Slag (GGBS) are effectively used in producing SCGC. In order to avoid heat curing treatment and facilitate ambient curing a part fly ash of was replaced by GGBS. In order to improve fresh properties and to control rapid setting 25% low calcium fly ash and 75% GGBS were used to produce SCGC. Sodium hydroxide and sodium silicate solution were used to activate the source materials. Experimental outcome concluded mix with 10 M and alkaline activator ratio of 4 was nominated as optimum as the mix had better workability, compressive strength and durability performance. The durability of SCGC is expressed in terms of capillary rise, weight loss or deterioration and loss in compressive strength in aggressive environment.
TL;DR: In this paper, the plasma electrolytic oxidation (PEO) treatment of Ti-6Al-4V alloy has been carried out in concentrated sodium silicate electrolyte, and the white coatings have great surface roughnesses and super hydrophilicity.
TL;DR: In this article, the effects of secondary raw materials content on the hydration of slag-cement mixtures were investigated, focusing on the important issue of studying cost-effective alkaline additives in binder mixtures based on phosphorus slag.
Abstract: We have investigated the effects of secondary raw materials content on the hydration of slag-cement mixtures. We focus on the important issue of studying cost-effective alkaline additives in binder mixtures based on phosphorus slag. We have analyzed the main phases in slag and ash and found that the most common phase was slag glass. This phase has considerable hydraulic properties due to high latent energy if we compare them to compare to those of the holocrystalline phase of the same compound. The process of adding small amounts of alkali and sulfates to vitreous slag activates its latent hydraulic properties. The effect of alkaline activators creates an alkaline environment required for the reactions between slag glass components. This article provides a way of determining the composition of raw mixtures and ensuring the possibility of correcting it, as well as a method for determining the proper (in terms of quality of concrete) pH value.
01 Aug 2018
TL;DR: In this article, the crystalline silica (SiO2) particle was successfully prepared using simple solution method from sodium silicate (Na2SiO3) precursor using FTIR spectrum of the sample confirms the presence of SiO2.
Abstract: The crystalline silica (SiO2) particle is successfully prepared using simple solution method from sodium silicate (Na2SiO3) precursor. The FTIR spectrum of the sample confirms the presence of SiO2. The X-ray diffraction (XRD) shows that the sample is cristobalite type of SiO2 which is comparable with ICSD ref. number of 01-076-0941. The crystallite size is about 28 nm as calculated by Scherrer method and the average particle diameter was about 697 nm as confirmed by Particle Size Analyzer (PSA) measurement. The Scanning Electron Microscope (SEM) image reveals that the sample reveal micro-flake with irregular rod-shaped morphology. The purity of sample is examined by X-ray Fluorescence (XRF) which shows about 93.1 mass % of pure SiO2 whereas, the purity of the raw precursor Na2SiO3 before synthesis is about 60.5 Mass %. The synthesized SiO2 particles can be used for several applications, where SiO2 is used in its crystalline phase.
TL;DR: In this paper, the fracture behavior of the optimized microcapsule was examined in a cement paste matrix and it was observed that most of the microcapsules seem to be spherical shaped and free-flowing powder.
TL;DR: In this paper, the influence of carboxylic collectors on the selective flotation of scheelite has been investigated, and the results showed that the combined effect of salt and carbonate with oleic and rosin acids showed synergistic effects, increasing the WO 3 grade to 11.2%.
TL;DR: In this article, the selective depression of calcite in a monazite-calcite flotation system was systematically studied using micro-flotation and electrokinetic tests as well as X-ray photoelectron spectroscopy (XPS) characterization and solution chemistry calculations.
TL;DR: In this paper, a study on the synthesis of alkali-activated binders based on the combination of tungsten mining waste mud (TMWM) with red clay brick waste (RCBW) with the use of sodium hydroxide (SH) and sodium silicate (SS) solution as alkaline activators is presented.
TL;DR: In this article, a new silica source for producing the alkaline activator, sugar cane straw ash (SCSA), was presented, and an activating suspension was prepared with SCSA and NaOH by means of a thermal bottle.
TL;DR: In this paper, the combination of palm oil fuel ash (POFA) and ground blast furnace slag (GBFS) at varying ratios was found to improve the compressive strength, durability and resistance against sulphuric acid attack.
TL;DR: In this paper, the authors focused on determining the rheological behavior and apparent activation energy of activated phosphorous slag (AAPS) with sodium silicate and NaOH at different SiO2/Na2O (S/N) and Na2O/Al2O3 (N/A) molar ratios.
TL;DR: In this paper, the effects of thermal treatment on the reactivity of the tailings and the use of different activating solutions on the physical properties, microstructure and leaching of harmful components are reported.
Abstract: Gold mining produces hazardous tailings wastes with elevated sulfur content and high levels of heavy metals including oxyanion elements such as V and As. This research investigated activation of these tailings with calcium hydroxide and sodium hydroxide/sodium silicate as a way to stabilize the material and limit leaching of harmful components. The effects of thermal treatment on the reactivity of the tailings and the use of different activating solutions on the physical properties, microstructure and leaching of harmful components are reported. The effect of adding ground granulated blast furnace slag to the tailings is also assessed. The use of 5 wt % Ca(OH)2 activating solution produces optimum performance increasing the immobilization efficiency of sulfates, arsenic and the other harmful elements. Heat-treating mine tailings at 900 °C slightly improves the reactivity but did not improved the immobilization efficiency. Microstructural analysis by TEM and XRD confirmed that stabilization is based on calcium sulfate and/or ettringite formation during alkali-activation. All materials achieved reasonable compressive strength after 28 days of curing and the potential for using alkali activation as a method to treat tailings from mining is discussed.
TL;DR: In this article, the changes that occur in the mechanical properties of sulfate saline soil solidified with an alkali-activated geopolymer due to varying the sulfate salt content were studied.