Aranca Nindya Puspa

Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember  

Tanti Haryati

Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember

Novita Andarini

Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Jember

DOI: https://doi.org/10.19184/ICL.v2i2.5616

ABSTRACT 

Fly ash, a solid waste product from the coal combustion process at the Paiton PLTU, contains 14.52-23.78% alumina (Al2O3). This can be extracted using NaOH for further utilization. The Al(OH)3 precipitate was obtained using a 4 M HCl solution with pH variations of 6 and 6.5. Meanwhile, Al metal was obtained using a reduction temperature variation of 600-700 oC with an interval of 50 oC using Mg metal reductant for 2.5 hours. The aluminum metal obtained was subjected to qualitative analysis by UV-Vis spectrophotometer and quantitative analysis by AAS. The Al(OH)3 precipitate obtained at a pH of 6.001 weighed 1.581 grams, with a yield of 61.83%, while at a pH of 6.5 it weighed 1.688 grams, with a yield of 66.02%. Applying a specific reagent for Al metal, alizarin, to qualitative analysis resulted in a maximum wavelength of 495 nm. A quantitative study was conducted utilizing the atomic absorption spectrophotometer (AAS) at a wavelength of 309.3 nm. The alumina content in fly ash was determined to be 14.52%, with an Al metal yield of 8.67% at a pH of 6 and 9.01% at a pH of 6.5, at an optimal reduction temperature of 650°C.   

Keywords: Fly ash, NaOH solvent extraction, Al metal.