The Application of Flame Atomic Absorption Spectrometry for Gold Determination in Some of Its Bearing Rocks

Hisham K. Fouad^*, Randa M. Elrakaiby, Mohamed D. Hashim

Analytical Chemistry Department, Nuclear Materials Authority, Cairo, Egypt.

DOI: 10.4236/ajac.2015.65040                

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.

Keywords

Gold, Determination, MIBK, Extraction, FAAS

Conflicts of Interest

The authors declare no conflicts of interest.

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