Full paperSynthesis of zeolites by alkaline activation of ferro-aluminous fly ash
Abstract
Zeolites were synthesized from fly ash by alkaline hydrothermal activation. High-Fe fly ash from the Teruel power station in NE Spain was the starting material. The activation was performed by 0.1 M NaOH and KOH solution in a closed system. Zeolite formation was studied as a function of temperature (60 and 150°C), reaction time (24, 168 and 336 h) and sample/solution ratio (30, 60, 100 and 200 gl−1). The zeolitic products synthesized were phillipsite, merlinoite, analcime, zeolite Na-P1 and nosean. Other reaction products identified were portlandite and bayerite. The activated material in the fly ash was mainly glass and quartz. The highest zeolite synthesis efficiency was 75%.
References (18)
- F. Mondragón et al.
Fuel
(1990) - D.H. Klein et al.
Environ. Sci. Technol.
(1975) - D.G. Coles et al.
Environ. Sci. Technol.
(1979) - W.L. Stout et al.
- H. Höller et al.
Fortschr. Mineral.
(1985) - N. Shigemoto et al.
Nippon Kagaku Kaishi
(1992) - N. Shigemoto et al.
J. Mater. Sci.
(1993) - R.M. Barrer
Hydrothermal Chemistry of Zeolites
(1982) - H. Höller
Contrib. Mineral. Petrol.
(1970)
Cited by (113)
Resource utilization of stone waste and loess to prepare grouting materials
2024, Journal of Environmental ManagementLoess, a terrestrial clastic sediment, is formed essentially by the accumulation of wind-blown dust, while stone waste (SW) is an industrial waste produced during stone machining. Utilising loess and SW to prepare environmentally-friendly supplementary cementitious materials can not only address environmental issues caused by solid waste landfills but also meet the demand of reinforcement of coal-seam floor aquifer for grouting materials. In this paper, the effects of the loess/SW mass ratio and calcination temperature on the transformation of calcined products are investigated and their pozzolanic activities are evaluated. The workability, environmental impact and cost of grouting materials based on cement and calcined products are also assessed. Experimental results reveal that higher temperatures favour the formation of free lime and periclase, which tend to be involved in solid-state reactions. Higher temperature and loess/SW mass ratio strengthens the diffraction peaks of dodecalcium hepta-aluminate (C12A7), dicalcium ferrite (C2F) and dicalcium silicate (C2S). The clay minerals in loess become completely dehydroxylated before 825 °C, generating amorphous SiO2 and Al2O3. Covalent Si–O bonds are interrupted and that disordered silicate networks are generated in the calcined products, which is confirmed by the increased strength of the Si29 resonance region at −60 ppm to −80 ppm. Although co-calcined loess and SW contain the most four-fold aluminium at 950 °C, recrystallisation depresses the pozzolanic activity. Hence, the loess/SW sample designated LS2-825 exhibits the better hydration activity. Additionally, grouting materials composed of cement and LS2-825 exhibit good setting times, fluidity, strength and a low carbon footprint in practical engineering applications, and they also provide the additional benefit of being cost effective.
Natural and synthetic zeolites for the removal of heavy metals and metalloids generated in the mining industry
2021, New Trends in Removal of Heavy Metals from Industrial WastewaterSince the industrial revolution period, the mining industry has brought benefits for human development. Mining is a primary industry relating several operations such as exploration, extraction, milling, purification, and refining of minerals. Oil industry is an example of mining with great importance in humanity. Metal and nonmetal industries also symbolize the principal activities with great impact on human development. However, this important industry has generated environmental impacts such as soil, water, and air contamination. Heavy metals and metalloids are bioaccumulative and cause several diseases including poisoning because these elements are accumulated in soft tissues of the body. Lead, cadmium, mercury, and arsenic are examples of heavy metals that cause poisoning in humans and other living beings. Depollution of contaminated sites with heavy metals and metalloids is necessary to ensure a high quality of life; moreover, it is part of the sustainable development. For the aforementioned purpose, in this chapter the technologies for the removal of heavy metals and metalloids generated from the mining industry are considered, with emphasis on the use of natural and synthetic zeolites. The latter type of zeolites is synthesized from wastes. In addition, the comparison between both types of zeolites for the removal of these elements is reviewed to identify the challenges in this important effort. Furthermore, the footprint carbon is estimated for these processes in order to evaluate the use of natural zeolites or those synthesized from wastes.
Synthesis and characterization of zeolite LTA by hydrothermal transformation of a natural Algerian palygorskite
2020, Applied Clay ScienceA palygorskitic-rich Algerian clay (Sif Pal) has been selected as Si source to synthesize zeolite LTA through a hydrothermal treatment by using sodium aluminate. Sif Pal is activated under reflux using hydrochloric acid solutions at different concentrations (4, 6 and 7 mol.L−1) in a ratio of 50 g.L−1 and then analysed using XRD, SEM and XRF analysis. The selected product (PalH1) is mixed with NaOH solutions at different concentrations (1, 2, 3, 4 and 5 mol.L−1), diverse NaAl2O3 quantities (1, 2, 3 and 5 g) and analysed after several nucleation (1, 2, 3 and 5 h) and crystallization (6, 18 and 24 h) times to check the influence of these parameters on the synthesis of zeolite LTA. To obtain almost pure (> 98%) zeolite LTA, the better experimental conditions were: 3 mol.L−1 of NaOH solutions, 3 g of sodium aluminate, 3 h for nucleation and 24 h for crystallization.
Study on the mineral phase characteristics of various Indian biomass and coal fly ash for its use in masonry construction products
2020, Construction and Building MaterialsThe productive utilization of the vast amount of industrial ash generated is of economic and environmental importance. The use of industrial ash in brick manufacturing gives the two-fold advantage of the reduced cost of fly ash bricks as well as efficient disposal of industrial ash. However, due to variations in chemical characteristics in the various types of ashes originated from different sources, and production processes often lead to restricted use in lime based fly ash bricks. To overcome this, comprehensive characterization of different industrial ashes is necessary to clearly define the chemical characteristics that have influencing role on the lime based fly ash bricks. Considering this, XRD patterns, FT-IR spectra, Raman spectra, SEM images, and chemical reactivity method have been collectively used for comprehensive characterization of industrial ashes, including their mineralogy, particle morphology, and lime reactivity. A total of six different ashes have been characterized, including two biomass ash and three coal based ash from local industries, and one coal based ash from thermal power plant. The primary aim of the study is to assess the suitability of the proposed experimental programme to characterize local industrial ashes and to evaluate their potential to use them as raw material in masonry construction products. From the present study, it is revealed that by and large, local coal-based industrial ash can be utilized in lime based fly ash bricks based on their comprehensive characterization. The results obtained by characterization of industrial ash are expected to provide helpful insights to evaluate their potential to manufacture masonry construction products.
Review of arsenic behavior during coal combustion: Volatilization, transformation, emission and removal technologies
2018, Progress in Energy and Combustion ScienceGrowing public awareness of the environmental impact of coal combustion has raised serious concerns about the various hazardous trace elements produced by coal firing. Arsenic deserves special attention due to its toxicity, volatility, bioaccumulation in the environment, and potential carcinogenic properties. As the main anthropogenic source of arsenic is coal combustion, its behavior in power plants is of concern. Unlike mercury, arsenic behavior in coal combustion has not been subjected to systematic, in-depth research. Different researchers have reached opposing conclusions about the behavior of arsenic in combustion systems and, as yet, there is relatively little research on arsenic removal technologies.
In this paper, the volatilization, transformation, and emission behavior of arsenic and its removal technologies are discussed in depth. Factors affecting the volatilization characteristics of arsenic are summarized, including temperature, pressure, mode of occurrence of arsenic, coal rank, mineral matter, and the sulfur and chlorine content of the fuel. The behavior of arsenic during oxy-fuel combustion and the effect of combustion atmosphere (O2, CO2, SO2 and H2O(g)) are also reviewed in detail.
In order to better understand the pathways of arsenic in a power plant environment, a particular focus in this work is the transformation mechanism of ultra-fine ash particles and the partitioning behavior of arsenic. Finally, the effects of air pollution control devices (APCDs) on arsenic emissions are examined, along with the effectiveness of flue gas arsenic removal technologies with different kinds of adsorbents, including calcium-based adsorbents, metal oxides, activated carbon, and fly ash.
State-of-the-art applications of fly ash from coal and biomass: A focus on zeolite synthesis processes and issues
2018, Progress in Energy and Combustion ScienceOver the years, the production of waste ash from many sources (e.g. coal, biomass, industrial, animal, and municipal solid waste) and from conventional and renewable energy technologies has increased, generating environmental problems due to the increasing amount of material disposed of in landfills.
Fly ash from coal and biomass represent the foremost waste products produced by fossil fuel combustion and alternative natural energy sources, respectively. These waste materials are most widely utilized in agricultural applications, soil stabilization, and the cement and concrete industries. Among the various methods proposed for the reuse of fly ash, conversion to zeolite offers the greatest benefits; the process diverts ash waste materials from disposal sites and transforms them into useful secondary products for applications ranging from environmental mitigation to catalysis. The vast amount of literature on fly ash application is the fruit of growing waste production and the consequent need to find innovative methods to reduce the amount of waste deposited in landfills.
This article summarizes studies concerning both coal and biomass fly ash. The characterization and potential applications of these materials are analysed in detail through reference to the numerous studies published on fly ash worldwide over the last number of decades. A considerable number of experiments have been conducted using ash as a raw material for zeolite synthesis, and many others concern the utilization of the newly-formed mineral. This paper discusses the key factors affecting zeolite synthesis, primarily from coal fly ash; the drawbacks of each approach are also analysed.