scholarly journals Extension of the ‘Inorganic Gel Casting’ Process to the Manufacturing of Boro-Alumino-Silicate Glass Foams

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2545 ◽  
Author(s):  
Acacio Rincon Romero ◽  
Sergio Tamburini ◽  
Gianmarco Taveri ◽  
Jaromír Toušek ◽  
Ivo Dlouhy ◽  
...  
Keyword(s):  
Silicate Glass ◽  
Casting Process ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Alkali Activation ◽  
Mechanical Stirring ◽  
Gel Casting ◽  
Fine Glass ◽  
Alumino Silicate ◽  
A New Technique

A new technique for the production of glass foams, based on alkali activation and gel casting, previously applied to soda-lime glass, was successfully extended to boro-alumino-silicate glass, recovered from the recycling of pharmaceutical vials. A weak alkali activation (2.5 M NaOH or NaOH/KOH aqueous solutions) of fine glass powders (below 70 µm) allowed for the obtainment of well-dispersed concentrated aqueous suspensions, undergoing gelation by treatment at low temperature (75 °C). Unlike soda-lime glass, the progressive hardening could not be attributed to the formation of calcium-rich silicate hydrates. The gelation was provided considering the chemical formulation of pharmaceutical glass (CaO-free) to the formation of hydrated sodium alumino-silicate (N-A-S-H) gel. An extensive direct foaming was achieved by vigorous mechanical stirring of partially gelified suspensions, comprising also a surfactant. A sintering treatment at 700 °C, was finally applied to stabilize the cellular structures.

scholarly journals Glass-Ceramic Foams from ‘Weak Alkali Activation’ and Gel-Casting of Waste Glass/Fly Ash Mixtures

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 588 ◽  
Author(s):  
Acacio Rincón Romero ◽  
Nicoletta Toniolo ◽  
Aldo Boccaccini ◽  
Enrico Bernardo
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Alkali Activation ◽  
Ceramic Foams ◽  
Mechanical Stirring ◽  
Gel Casting ◽  
Alumino Silicate ◽  
Crystal Phases

A ‘weak alkali activation’ was applied to aqueous suspensions based on soda lime glass and coal fly ash. Unlike in actual geopolymers, an extensive formation of zeolite-like gels was not expected, due to the low molarity of the alkali activator (NaOH) used. In any case, the suspension underwent gelation and presented a marked pseudoplastic behavior. A significant foaming could be achieved by air incorporation, in turn resulting from intensive mechanical stirring (with the help of a surfactant), before complete hardening. Dried foams were later subjected to heat treatment at 700–900 °C. The interactions between glass and fly ash, upon firing, determined the formation of new crystal phases, particularly nepheline (sodium alumino–silicate), with remarkable crushing strength (~6 MPa, with a porosity of about 70%). The fired materials, finally, demonstrated a successful stabilization of pollutants from fly ash and a low thermal conductivity that could be exploited for building applications.

scholarly journals Biosilicate® Glass-Ceramic Foams From Refined Alkali Activation and Gel Casting

2021 ◽  
Vol 7 ◽  
Author(s):  
Enrico Bernardo ◽  
Hamada Elsayed ◽  
Acacio Rincon Romero ◽  
Murilo C. Crovace ◽  
Edgar D. Zanotto ◽  
...  
Keyword(s):  
Glass Ceramics ◽  
Casting Process ◽  
Alkali Activation ◽  
Weakly Alkaline ◽  
Ceramic Foams ◽  
Porous Bodies ◽  
Gel Casting ◽  
Fine Glass ◽  
Micro Tomography ◽  
45S5 Bioglass

Biosilicate® glass-ceramics are among the most valid alternatives to 45S5 Bioglass. They combine a similar bioactivity and bioresorbability as the 45S5 with superior mechanical strength, owing to the crystallization of a Na–Ca silicate phase. This crystallization may be experienced upon viscous flow sintering of fine glass powders, thus configuring a sinter-crystallization process. As crystallization is seldom complete, sintering can also be applied to semicrystalline powders. The sintering/crystallization combination may be exploited for shaping highly porous bodies, to be used as scaffolds for bone tissue engineering, in the form of foams. The present study aims at exploring a gel-casting process, based on the room temperature foaming of powders suspended in a “weakly alkaline” (1 M NaOH) aqueous solution, followed by sintering at 1,000°C. The gelation of suspensions is attributed to the formation of hydrated compounds, later decomposed upon firing. Amorphous powders provided more intense gelation than semicrystalline ones, promoted a more homogeneous foaming, and stimulated a substantial crystallization upon firing. The homogeneity of foamed samples was assessed using micro-tomography and was further improved by casting foamed suspensions (“foam casting”) before setting.

scholarly journals Recyclable Porous Glass-Ceramics from the Smelting of MSWI Bottom Ash

Ceramics ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 1-11
Author(s):  
Patricia Rabelo Monich ◽  
Hugo Lucas ◽  
Bernd Friedrich ◽  
Enrico Bernardo
Keyword(s):  
Porous Glass ◽  
Density Ratio ◽  
Bottom Ash ◽  
Glass Ceramics ◽  
Waste Incineration ◽  
Soda Lime ◽  
Raw Material ◽  
Soda Lime Glass ◽  
Mswi Bottom Ash ◽  
Gel Casting

Material from the electric arc furnace smelting of municipal solid waste incineration (MSWI) bottom ash was easily converted into highly porous glass-ceramics by a combination of inorganic gel casting and sinter-crystallization at 1000 °C. In particular, the gelation of aqueous suspensions of fine glass powders, transformed into “green” foams by intensive mechanical stirring, occurred with a limited addition of alkali activator (1 M NaOH). The products coupled the stabilization of pollutants with good mechanical properties (e.g., compressive strength approaching 4 MPa). Interestingly, they could be used also as raw material for new glass-ceramic foams, obtained by the same gel casting and sintering method, with no degradation of chemical stability. Limitations in the crushing strength, derived from the limited viscous flow densification of semi-crystalline powders, were overcome by mixing powders from recycled foams with 30 wt% soda-lime glass. The new products finally featured an even higher strength-to-density ratio than the foams from the first cycle.

scholarly journals Effect of sintering temperature on physical and structural properties of Alumino-Silicate-Fluoride glass ceramics fabricated from clam shell and soda lime silicate glass

2019 ◽  
Vol 12 ◽  
pp. 1909-1914 ◽  
Author(s):  
Wan Nurshamimi Wan Jusoh ◽  
Khamirul Amin Matori ◽  
Mohd Hafiz Mohd Zaid ◽  
Norhazlin Zainuddin ◽  
Mohammad Zulhasif Ahmad Khiri ◽  
...  
Keyword(s):  
Structural Properties ◽  
Silicate Glass ◽  
Sintering Temperature ◽  
Glass Ceramics ◽  
Soda Lime ◽  
Fluoride Glass ◽  
Clam Shell ◽  
Alumino Silicate ◽  
Soda Lime Silicate Glass

Planar waveguides prepared by K+–Na+ field-assisted ion exchange in different types of silicate glass

1999 ◽  
Vol 14 (7) ◽  
pp. 3122-3129 ◽  
Author(s):  
Jitka Kosíková ◽  
Josef Schröfel
Keyword(s):  
Refractive Index ◽  
Ion Exchange ◽  
Electric Field ◽  
Silicate Glass ◽  
Depth Profile ◽  
Soda Lime ◽  
Planar Waveguides ◽  
Soda Lime Glass ◽  
Different Types

The goal of this work was to address the technological problems associated with waveguide preparation by thermal- and electric-field–assisted K+–Na+ ion exchange in two types of soda-lime glass: common FTD and special pure GIL49. The number of modes, depth, profile, and the change in refractive index were measured for waveguides prepared at temperatures between 250 and 410 °C and electric-field values between 0 and 50 V/mm. Although the influence of some admixture content inside the glass was relatively high, all of these parameters were controlled accurately and repeatedly by the electric field.

scholarly journals Durability of Mortar Made with Fine Glass Powdered Particles

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Rosemary Bom Conselho Sales ◽  
Fernando Augusto Sales ◽  
Enio Pazini Figueiredo ◽  
White José dos Santos ◽  
Nelcy Della Santina Mohallem ◽  
...  
Keyword(s):  
Portland Cement ◽  
Soda Lime ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Soda Lime Glass ◽  
Colorless Glass ◽  
Alkali Aggregate Reaction ◽  
Cement Mortars ◽  
Fine Glass

Different studies investigate the use of waste glass in Portland cement compounds, either as aggregates or as supplementary cementitious materials. Nevertheless, it seems that there is no consensus about the influence of particle color and size on the behavior of the compounds. This study addresses the influence of cement replacement by 10 and 20% of the colorless and amber soda-lime glass particles sized around 9.5 μm on the performance of Portland cement mortars. Results revealed that the partial replacement of cement could contribute to the production of durable mortars in relation to the inhibition of the alkali-aggregate reaction. This effect was more marked with 20% replacement using amber glass. Samples containing glass microparticles were more resistant to corrosion, in particular those made of colorless glass. The use of colorless and amber glass microparticles promoted a reduction in wear resistance.

Highly efficient biocide silver-doped soda lime glass for application in water quality optical sensors

2020 ◽  
Vol 111 (10) ◽  
pp. 857-862
Author(s):  
Branimir Bajac ◽  
Jovana Stanojev ◽  
Slobodan Birgermajer ◽  
Milena Radojevic ◽  
Jovan Matovic
Keyword(s):  
Water Quality ◽  
Optical Sensors ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Highly Efficient
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