TITLE:
The Application of Flame Atomic Absorption Spectrometry for Gold Determination in Some of Its Bearing Rocks
AUTHORS:
Hisham K. Fouad, Randa M. Elrakaiby, Mohamed D. Hashim
KEYWORDS:
Gold, Determination, MIBK, Extraction, FAAS
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.6 No.5,
March
31,
2015
ABSTRACT: A developed method was designed for gold
determination directly in organic medium in some sedimentary rocks (fine
sandstone, carbonates), pyrite, serpentine and international standard gold sample
(MA-1a) using flame atomic absorption spectroscopy (FAAS). Instrumental parameters;
burner angle, fuel flow rate, band pass and burner height together with
chemical parameters; different media, leaching and interference effect were optimized
to improve gold determination. Selective leaching using a new mixture (5% KCN,
5% Na2S2O3 and hydrogen peroxide) offered
maximum leaching percentage of gold (>99%) with minimal concentration of
accompanying elements. Extraction parameters using methyl isobutyl ketone
(MIBK) from 3 M HCl were optimized for more than 99% gold extraction, followed
by scrubbing using 0.1 M HCl. Gold was determined directly in organic phase.
Beer’s law was obeyed from 0.01 μg/ml to 10 μg/ml. Standard deviation (from
0.017 to 1.05) and percentage error (from 1.5% to 2.5%) using the present
developed AAS method were calculated.