Abstract
This paper takes the coal fly ash as the material and makes zeolite with low thermal conductivity under a two-step synthesis for the purpose of thermal insulation. It studies main factors affecting zeolite such as the different concentration of NaOH, the solid-liquid ratio, the silica-alumina ratio, and the crystallization temperature. The optimal conditions were obtained that the NaOH concentration was 3 mol/L, the solid-liquid ratio was 10 : 1, the silica-alumina ratio was 2, and the crystallization temperature was 12°C. Zeolites have multiple pores and skeletal structures under SEM observation. The mean particle size was 2.78 um of concentrated distribution. The pore volume was 0.148 m3/g measured by BET analysis, the specific surface was 118.6 m2/g, and the thermal conductivity was 0.153 W/(m·K). Zeolite was proved to be a qualified insulation material which can be used in thermal insulation coating as a new material of energy conservation.
Highlights
Fly ash is the largest amount of industrial waste in the world
More than 150 zeolites have been synthesized from CFA in the past few years [4]
This paper studied the influence of coal fly ash on zeolite with four NaOH concentrations (1.5, 2, 3, and 4 mol/L)
Summary
Fly ash is the largest amount of industrial waste in the world. There is still a proportion of CFA that is discharged into ponds or landfills, which causes serious environmental problems and significant distress to local communities [1, 2]. Studies in the literature suggest that it is possible to synthesize zeolites from natural materials and industrial residues, but all of these processes employ large quantities of sodium hydroxide (NaOH) and require high temperatures for performing the alkaline fusion [11]. Such processes have significant costs and are not always reproducible [12]. Zeolites can be used in wastewater purification because they efficiently adsorb positively charged pollutants in wastewater, such as heavy metals [15,16,17] They have not been applied to thermal insulation. We selected qualified zeolites of low thermal conductivity by changing experimental conditions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
