Neutron activation analysis

Development of a simple and efficient two-step microwave-assisted digestion method for the determination of REEs, HFSEs and other elements in granite samples by ICP-OES

“…Granite samples are generally composed of SiO 2 , Al 2 O 3 , Fe 2 O 3 , CaO, MgO and K 2 O. 22 Under high pressure and at elevated temperature, many metal oxides can be attacked by HCl to produce generally soluble chloride salts. The use of various fluoride containing reagents such as HF, NH 4 HF 2 and HBF 4 along with mineral acids such as HNO 3 and HCl is generally employed for the digestion of different solid matrices containing silica.…”

“…Several decomposition procedures exist in the literature for different types of geological samples for the determination of REEs and other valuable metals. 22–26 The most significant analytical difficulties encountered, particularly, in the analysis of HFSEs are incomplete decomposition of acid-resistant accessory minerals and instability of solutions obtained after sample digestion because of possible hydrolysis and their polymerization.…”

“…Sample preparation of geological samples has traditionally been carried out by means of acid digestion (under both open and closed conditions) 22,26–29 and fusion/sintering methods. 30–33 Acid digestion methods involve the use of different combinations of mineral acids such as HF, HCl or HNO 3 .…”

Evaluation of two methods allowing the full preparation in a single day of silicate rocks in view of radiogenic isotope (Nd, Sr, and Pb) analyses

“…More specifically, commercially available products used to be severely contaminated by LREEs due to the concomitant production, in the same facilities, of lithium tetraborate containing large quantities (mass fraction of 15–20%) of lanthanum oxide used as a strong absorber in the fused disk beads prepared for XRF spectrometric analyses. 16 In order to minimize blank problems, LiBO 2 can be dissolved in hot water and purified by recrystallization, 10 but this method is relatively tedious. 17 Alternatively, LiBO 2 can be dissolved in 3 mol per L HNO 3 and passed through EXC cartridges of DGA resin to get rid of the REE, Sc, and Y, before the flux is recovered by evaporation followed by a high T (720 °C) treatment to remove residual nitric acid and water.…”