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 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.

Synthesis and Characterization of Zeolite from Glass by Hydrothermal Processing

2013 ◽  
Vol 761 ◽  
pp. 91-94
Author(s):  
Masato Tsujiguchi ◽  
Tadashi Kobashi ◽  
Junji Kanbara ◽  
Yasuhiko Utsumi ◽  
Nobuaki Kakimori ◽  
...  
Keyword(s):  
Coal Fly Ash ◽  
Soda Lime ◽  
Xrd Analysis ◽  
Alkali Metal Hydroxide ◽  
High Tech ◽  
Soda Lime Glass ◽  
Production Volume ◽  
Silica Alumina ◽  
Plasma Displays

Zeolite is a microporous aluminosilicate material with uniform pore size of less than 2 nm and chemical, mechanical, and thermal stability. In general zeolite is synthesized from silica, alumina, mineralizer (alkali metal hydroxide and fluoride) and water. Recently it has been reported that various zeolites is synthesized from soda-lime glass, slag and coal fly ash as silica and alumina source. On the other hand, the production volume of various kinds of high-quality glass which are utilized for high-tech products such as liquid crystal displays and plasma displays is rapidly increasing. The purpose in this study is to synthesize a zeolite from crushed aluminoborosilicate glasses which is used as LCD panels glass substrate. According to the XRD analysis, it was found that the synthesized sample had zeolite related structure. And the results of SEM observation of the products suggest that the zeolite structure was obtained as well as XRD results. It was thought that zeolite was successfully synthesized from the glass by this synthetic processing.

Preparation of glass ceramic foams for thermal insulation applications from coal fly ash and waste glass

2016 ◽  
Vol 112 ◽  
pp. 398-405 ◽  
Author(s):  
Mengguang Zhu ◽  
Ru Ji ◽  
Zhongmin Li ◽  
Hao Wang ◽  
LiLi Liu ◽  
...  
Keyword(s):  
Fly Ash ◽  
Thermal Insulation ◽  
Glass Ceramic ◽  
Coal Fly Ash ◽  
Waste Glass ◽  
Ceramic Foams

scholarly journals Glass-Ceramic Foams from Alkali-Activated Vitrified Bottom Ash and Waste Glasses

2020 ◽  
Vol 10 (16) ◽  
pp. 5714
Author(s):  
Miroslava Hujova ◽  
Patricia Rabelo Monich ◽  
Jaroslav Sedlacek ◽  
Miroslav Hnatko ◽  
Jozef Kraxner ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Bottom Ash ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Phase Assemblage ◽  
Weakly Alkaline ◽  
Glass Addition ◽  
Ceramic Foams ◽  
Weakly Alkaline Solution ◽  
Inorganic Waste

Both vitrified bottom ashes (VBAs) and waste glasses are forms of inorganic waste material that are widely landfilled, despite having some economic potential. Building on previous studies, we prepared glass-ceramic foams by the combination of VBA with either soda-lime glass (SLG) or borosilicate glass (BSG). Suspensions of fine powders in weakly alkaline solution underwent gelation, followed by frothing at nearly room temperature. Hardened “green” foams were sintered, with concurrent crystallization, at 850–1000 °C. All foams were highly porous (>70%), with mostly open porosity. The glass addition was fundamental in both gelation (promoting the formation of carbonate and silicate hydrated phases) and firing steps. While SLG addition enhanced the viscous flow sintering, without a significant impact on the crystallization of gehlenite, the main crystalline phase from the devitrification of VBA, BSG addition caused a reactive sintering, with remarkable changes in the phase assemblage. The glass addition generally also allowed lower sintering temperatures and yielded products with excellent crushing strength. However, only specific conditions resulted in the complete immobilization of pollutants (e.g., Cr3+ ions).

Porous mullite ceramics derived from coal fly ash using a freeze-gel casting/polymer sponge technique

2012 ◽  
Vol 20 (1) ◽  
pp. 219-226 ◽  
Author(s):  
J. H. Lee ◽  
H. J. Choi ◽  
S. Y. Yoon ◽  
B. K. Kim ◽  
H. C. Park
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Gel Casting ◽  
Porous Mullite ◽  
Mullite Ceramics

Extraction of Aluminum from Coal Fly Ash by Alkali Activation with Microwave Heating

2016 ◽  
Vol 13 (S1) ◽  
pp. S181-S187 ◽  
Author(s):  
Nengsheng Liu ◽  
Jinhui Peng ◽  
Libo Zhang ◽  
Shixing Wang ◽  
Shaojun Huang ◽  
...  
Keyword(s):  
Fly Ash ◽  
Microwave Heating ◽  
Coal Fly Ash ◽  
Alkali Activation

scholarly journals Alkali activation of fresh and deposited black coal fly ash with high loss on ignition

2014 ◽  
Vol 30 (2) ◽  
pp. 103-115 ◽  
Author(s):  
Martin Sisol ◽  
Miroslava Drabová ◽  
Juraj Mosej
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Alkali Activation ◽  
Loss On Ignition ◽  
Black Coal ◽  
High Loss

Streszczenie Elektrownie i elektrociepłownie stosujące węgiel jako paliwo mają istotne znaczenie jako źródła energii, choć z drugiej strony wytwarzają duże ilości popiołów lotnych ze spalania węgli. Tylko mała część tych popiołów jest użytkowana jako surowce odpadowe. Zazwyczaj popioły lotne są depo- nowane w osadnikach, co stwarza poważne zagrożenie środowiskowe. Możliwości zagospodarowania popiołów lotnych stwarza przede wszystkim przemysł materiałów budowlanych; tym niemniej użyt- kowanie popiołów lotnych z podwyższoną zawartością niespalonych cząstek węgla, co wyraża się wartością straty prażenia, jest ograniczone do popiołów wykazujących stratę prażenia 2-5% zgodnie z europejską normą EN 206-1. Dlatego też popioły lotne z wysoką zawartością niespalonych cząstek węgla są deponowane w osadnikach. Depozycja popiołów lotnych, biorąc pod uwagę także czynniki egzogeniczne i biogeniczne, powoduje zmiany składu chemicznego i fazowego popiołów, co powo- duje, że możliwości ich późniejszego wykorzystaniajako surowce odpadowe,jeszcze bardziej maleją. Obecnie, jedyną możliwością użytkowania popiołów lotnych wykazujących wysoką stratę prażenia, jest synteza geopolimerów. Te nowe materiały nieorganiczne są otrzymywane w wyniku reakcji nie- organicznej polikondensacj i glinokrzemianów z krzemianem sodu w środowisku wysoce alkalicznym. Praca zajmuje się produkcją spoiw geopolimerowych otrzymywanych w wyniku aktywacji alka- licznej popiołów lotnych pochodzących z bieżącej działalności oraz ze zwałowiska. Popioły lotne pochodzą ze spalania węgla kamiennego w kotłach pyłowych, wykazując wysoką zawartość niespa- lonych cząstek węgla. Wartość straty prażenia w tych popiołach przekracza 20%. Są one aktywowane alkalicznie roztworami wodorotlenku sodowego i szkła wodnego. Analizowano zależność wytrzy- małości na ściskanie syntetyzowanych geopolimerów od stosunku SiO2/Na2O, zawartości Na2O i zawartości wody. Wytrzymałość na ściskanie aktywowanych alkalicznie popiołów lotnych de- ponowanych (DPA) i z bieżącej działalności (FFA) wynosi odpowiednio 39,8 MPa i 46,8 MPa po 7 dniach i wzrasta z czasem.

scholarly journals Chemical Stability and Leaching Behavior of One-Part Geopolymer from Soil and Coal Fly Ash Mixtures

Minerals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 411 ◽  
Author(s):  
April Tigue ◽  
Roy Malenab ◽  
Jonathan Dungca ◽  
Derrick Yu ◽  
Michael Promentilla
Keyword(s):  
Fly Ash ◽  
Chemical Stability ◽  
Coal Fly Ash ◽  
Embodied Energy ◽  
Synthesis Process ◽  
Attractive Alternative ◽  
Alkali Activation ◽  
Acid Attack ◽  
X Ray ◽  
Stabilized Soil

Aluminosilicate minerals have become an important resource for an emerging sustainable material for construction known as geopolymer. Geopolymer, an alkali-activated material, is becoming an attractive alternative to Portland cement because of its lower carbon footprint and embodied energy. However, the synthesis process requires typically a two-part system for alkali activation wherein the solid geopolymer precursor is mixed with aqueous alkali solutions. These alkali activators are corrosive and may be difficult to handle in the field-scale application. In this study, a one-part geopolymer in which coal fly ash was mixed with solid alkali activators such as sodium hydroxide and sodium silicate to form a powdery cementitious binder was developed. This binder mixed with soil only requires water to form the soil-fly ash (SO-CFA) geopolymer cement, which can be used as stabilized soil for backfill/foundation. This geopolymer product was then evaluated for chemical stability by immersing the material with 5% by weight of sulfuric acid solution for 28 days. Indication suggests that the geopolymer exhibited high resistance against acid attack with an observed increase of unconfined compressive strength even when the immersion time in acidic solution was increased to 56 days. The mineralogical phase, microstructure, and morphology of the material were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), respectively. Results not only confirmed the formation of gypsum due to acid attack but also indicated the dissolution of anorthite and albite that may have caused the microstructure to be composed of sodium aluminosilicate hydrate (N–A–S–H) and calcium (alumino) silicate hydrate (C(–A)–S–H) with poly(ferro-sialate-siloxo) and poly(ferro-sialate-disiloxo) networks. A column leaching test with deionized water was also performed on the soil-fly ash geopolymer to study the leachability of metals in the material. Results showed that arsenic exhibits higher mobility in the geopolymer as compared to that of cadmium, chromium, and lead.

Effect of particle size and alkali activation on coal fly ash and their role in sintered ceramic tiles

2017 ◽  
Vol 37 (4) ◽  
pp. 1847-1856 ◽  
Author(s):  
Yang Luo ◽  
Shuhua Ma ◽  
Chunli Liu ◽  
Zhenqing Zhao ◽  
Shili Zheng ◽  
...  
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Coal Fly Ash ◽  
Alkali Activation ◽  
Ceramic Tiles ◽  
Sintered Ceramic ◽  
Effect Of Particle Size
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