Extraction–atomic absorption spectrometric method for the determination of the platinum group elements and gold in copper–nickel ores using an autoclave sample decomposition technique

Abstract

An ETAAS method was developed to determine the platinum group elements and gold in copper-nickel ores using a single sample. It is based on an approach involving interconnected consideration of the main components of analytical procedure (autoclave decomposition of sample; collective extractive preconcentration of metals with a mixture of alkylaniline hydrochloride and petroleum sulfides; and atomic absorption spectrometric analysis of the extract). The concentrations of elements determined in standard reference materials (lode and impregnation copper-nickel sulfide ores) were found to be in accordance with the certified values, within experimental error. The relative standard deviation varied between 2 and 17% at 0.05-10 mg kg-1 element concentrations. The determination limits were 0.001-0.06 mg kg-l for a 5 g sample and an extract volume of 5 ml.

Utility of solid phase extraction for spectrophotometric determination of gold in water, jewel and ore samples

“…The performance of the proposed method was assessed by calculation of the t-value (for accuracy) and F-test (for precision) compared with GFAAS method [13]. The mean values were obtained in a Student's t-and F-tests at 95% confidence limits for five degrees of freedom [38].…”

“…For the determination of trace levels of gold in geological samples, sensitive methods are frequently required. Many methods to determine gold have been reported, such as flame atomic absorption spectrometry (FAAS) [12], graphite furnace (GFAAS) or electrothermal atomic absorption spectrometry (ETAAS) [13], inductively coupled plasma mass spectrometry [14], and spectrophotometry [15]. Because the procedures of the sensitive analysis methods mentioned above are generally subject to the effect of a number of interferences, suitable preconcentration and effective separation processes are frequently required, such as the use of solvent extraction [12,16], active carbon adsorption [17], polyurethane foam concentration [18], solid-phase extraction [19], and complexforming resin concentration [20].…”

Sample Digestion Methods for the Determination of Traces of Precious Metals by Spectrometric Techniques

“…84 The concentrations of PGM and gold (0.01 -11.3 µg g -1 ) in copper-nickel ores, corresponding well with the certified values, were determined by GFAAS using an autoclave decomposition technique along with HCl, HF and HNO3. 82 Hydrofluoric acid and aqua regia have also been used for the digestion of soil matrices when determining palladium at ng levels by GFAAS. 94 Mixtures of HNO3, HF and H3BO3 and a pressure ashing device have recently been applied to digest road dust (a candidate reference material) prior to the detection of platinum, palladium and rhodium (ng g -1 levels) by various techniques.…”

“…10 Combined digestion procedures, a wet acid treatment followed by alkaline oxidizing fusion of an undissolved residue, are often applied for improving the recovery of the metals. [74][75][76] The use of hydrofluoric acid in the digestion procedures is preferable, particularly when examining geological 74,[76][77][78][79][80][81][82][83][84][85] and environmental materials. 72,[86][87][88][89][90][91][92][93][94] High-pressure systems and microwave heating are widely applied for improving the digestion of such samples.…”

Rapid Determination of Gold in Geological Samples Using Flow Injection Solid-Phase Chemiluminescence

“…For the determination of trace levels of gold in geological samples, sensitive methods are frequently required. Many methods to determine gold have been reported, such as flame atomic absorption spectrometry (FAAS), 1 graphite furnace (GFAAS) or electrothermal atomic absorption spectrometry (ETAAS), 2 inductively coupled plasma mass spectrometry, [3][4][5][6] and spectrophotometry. [7][8][9][10] Because the procedures of the sensitive analysis methods mentioned above are generally subject to the effect of a number of interferences, suitable preconcentration and effective separation processes are frequently required, such as the use of solvent extraction, [11][12][13] active carbon adsorption, 14 polyurethane foam concentration, 15 solid-phase extraction, 16,17 and chelate-forming resin concentration.…”