Comparison Between the Use of Sodium and Lithium Tetraboratein Platinum‐group Element Determination by Nickel Sulphide Fire‐assay

Abstract

The alternative use of lithium tetraborate and/or sodium tetraborate as flux constituents in the quantitative determination of platinum group elements (PGE) in standard reference materials SARM‐7, CHR‐Pt+ and CHR‐Bkg by graphite furnace atomic absorption spectrometry after preconcentration by nickel sulphide fire assay was reinvestigated. Results showed that lithium tetraborate has a lower recovery rate than sodium tetraborate, except for chromitites with PGE abundances in the ppm‐range. Best results for chromitites were obtained by using a mixture (1:1) of the two tetraborates. Examination of the NiS‐reguli by an electron microprobe revealed finer grain‐sizes of PGE‐phases for lithium tetraborate and coarser ones for sodium tetraborate, the finer grains being a possible reason for greater losses during analysis filtration.

Improved Platinum‐Group Element Extraction by NiS Fire Assay from Chromitite Ore Samples Using a Flux Containing Sodium Metaphosphate

“…A number of methods have been reported in the literature (Table 1) based on the nickel sulfide fire assay procedure. The methods of Borthick and Naldrett (1984) and Asif and Parry (1990) were designed specifically for chromite, whilst those of Zereini et al (1994) and Robért et al (1971) are orientated towards sulfide ores and silicates. Asif and Parry (1990) claimed a better recovery with their method, although no petrography of the glassy slag was published.…”

Long-Term Monitoring of Palladium and Platinum Contents in Road Dust of the City of Munich, Germany

“…However, before this advantage of fire assay techniques can be exploited to the full, large sample quantities of at least 100 g or more should be available. Fire assays also require special equipment and considerable experience and knowledge especially in finding the appropriate sample adapted mixture of chemicals, optimized temperature profiles and optimal dissolution conditions for the collector phase to avoid loss of analyte (Zereini et al 1993(Zereini et al , 1994(Zereini et al , 2007.…”

Platinum Group Elements

“…Zereini et al [36] were the first to detect the existence of elevated Pt concentrations in soils along roads with higher volumes of traffic in Germany, using a proven, reliable method which combines nickel sulfide (NiS)-fire assay with GF-AAS (graphite furnace atomic absorption spectrometry [37]. Since then, a number of studies have consistently shown that PGE concentrations in soils along roads are often considerably higher than typical background levels (<1 mg kg À1 ) and have increased over time (for example [9,10]).…”