Study of reference sample candidate for the noble metal contents (PGM, Au, Ag) in a graphitized rocks

The regularities of formation of noble- and rare-metal mineralization in Cenozoic coaliferous deposits in the southern Far East

“…The problem of estimation of the migration properties of NMs and, hence, their considerable loss during analytical and technological processes was repeatedly considered elsewhere (Arbuzov and Ershov, 2007;Arbuzov et al, 2006;Dai et al, 2003Dai et al, , 2004Dai et al, , 2005Ketris, Yudovich, 2009;Kotlyar et al, 2005;Mitkin, 2006;Mitkin et al, 2009Mitkin et al, , 2010Seredin, 2004Seredin, , 2007Seredin and Povarennykh, 1995;Slobodskoi, 1978;Varshal et al, 1994Varshal et al, , 1996Zhang et al, 2002). In the 1990s, Varshal et al (1994) showed that during analysis of carbonaceous rocks, the NM loss through sorption and formation of volatiles can reach one or two orders of magnitude.…”

“…The main reason of underestimated PGE and Au contents in black shales and brown coals by the conventional methods of chemical sample preparation is the occurrence of these elements as metal-organic compounds, which decompose on heating to produce the volatile compounds. To prevent gold and PGE loss, the Institute of Inorganic Chemistry, Novosibirsk, elaborated new methods of chemical sample preparation based on fluoroxidation decomposition (Khanchuk et al, 2008;Mitkin, 2006;Mitkin et al, 1999Mitkin et al, , 2003Mitkin et al, , 2009Mitkin et al, , 2010. These methods proved their efficiency and ensure a valid determination of NM contents in any geologic materials, including carbonaceous ones.…”