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GEOLOGICA BALCANICA, 30. 3-4, Sofia, Febr. 2001, p. 77-88 Chalcophile elements in some Bulgarian coals Jordan Kortenski, Anton Sotirov University of Mining and Geology "Sv. Ivan Rilski", Sofia, 1100, Bulgaria. (submitted: 24.06.1999; accepted for publication: 28.06.1999; revised version received 23.06.2000) 11:. KopTeHCKH, A. CoTHpos- XaAKOr/iUAbHble 3AeMeHmbl Abstract. The occurrence and distribution of Cu, Zn, As, B HeKomopblX 6oAzapcKux yzARX . .[Vrll npHCYTCTBHll Cu, Mo, Ag, Sn and Pb was investigated in coals of various Zn, As, Mo, Ag, Sn H Pb Hccne.uosaHbT yrnH HJ TpHHa.u rank (ranging from lignite to anthracite) from thirteen uaTH 6onrapcKHX 6acceiiHoB c paJHOH cTeneHbTO yrne coal basins in Bulgaria. The concentrations of almost all QJHKaUHH. Co.uep)l(aHHll 6oJJblllHHCTBa H3 :meMeHTOB B elements in the coal ash and bulk coal samples from the 30JJe yrneit nepHHKCKOTO, CaMOKOBCKOTO, COQJHHCKOTO Pernik, Samokov and Sofia Basins are the highest and 6acceHHOB MaKCHMaJJbHbTe H 6onee BHCOI<He no cpaBHe higher than the respective Clarke values, ranges for most HHTO C KJJapKOM H Cpe.UHHM paHTOM. )].Jill .llPYTHX yrJJl!X coals. In other coals (from Kyustendil, Karlovo, Oranovo (HJ KTOcTeH.UHJJCKoro, Kapnosci<oro, OpaHOBCKoro H 3a and Maritza-West Basins) the contents only of some ele rra.uHoMapuui<oro 6acceHHOB) KOHUeHTpaUHll TOJlbkO He ments are higher than the Clarke values. The element KOTOpbTX :meMeHTOB 6onee BbTCOKOH 'feM KJJapKOBOH . concentrations in the coals from the Belibreg, Suhostrel Co.uep)l(aHHll 3JJeMeHTOB B yrJJl!X Eeno6pe)I(Koro, Cyxoc and Balkan Basins are the lowest. rpencKoro u Eani<aHCKoro 6acceHHOB MHHHMaJJbHO. B The organic affinity of the elements is found to be very JaTTa.llHOMapHUKHX YTJJl!X 3JJeMeHTbT HMeTOT O'feHb high in the coals from Maritza-West. The organic affinity CHJJbH)'lO npHBl!JaHHOCTb K opraHH'"IeCKoMy uer.uecTBy. B also predominates in the coals from the Sofia, Karlovo, 60JJbliJOH CTeneHb CBl!JaHH TO)I(e C opraHH'feCKOM Be Stanyantzi, Pernik, Kyustendil, Oranovo and Svoge Ba I.UeCTBOM 3JTeMeHTbl B yrnllx HJ Co4Juiici<oro, Kapnosc sins. On the other hand, the inorganic affinity was exhibit Koro, CTaHl!HCKOTO, OpaHOBCKOTO, nepHHKCKOTO, KTOc ed in coals from the Belibreg, Suhostrel and partly Gabro TeH.UHJTCKOTO u CuoreHcKoro 6acceHHOB. B cyxocTpenc vitza. The organic affinity of As and Mo and inorganic KHX, 6eno6pe)I(KHX H ra6pOBHliJKHX yrJJl!X rrpeo6JJa.UaTOT affinity of Sn are the highest. The organic affinity of Cu, 3JJeMeHTbT, CBl!JaHbTe c HeopraHH'feCKHM uer.uecTBOM. As Pb, partly Ag is also high and Zn has intermediate affinity. H Mo npHypo'feHH K opraHH'feCKOM)' uer.uecTBy B caMOH Major factors controlling the occurrence and concen 6oJTblllOH cTeneHb. Cu, Pb u Ag TO)I(e CBl!JaHbT npeHM)' trations of the investigated elements in the Bulgarian r.uecTBeHHO c opraHH'feCKHM uer.uecTBOM, Sn - c Heopra coals are: l) the occurrence in the plant tissue and in the HH'feCKHM uer.uecTBOM, a Zn HMeeT paJHax npHypo'"leH rocks from the peat bog coastline; 2) source areas for sur HOCTb B pa3HbTX yrJJl!X. face and ground waters which transported the elements nl!Tb QJaKTOpH onpe.ueJJl!TOT TTpHCYCTBHe H CO.Ilep)l(a into the peat bogs; 3) the pH values in the ancient peat HHe HCCJTe.llOBaHHbTX 3JJeMeHTOB B 6oJJrapCKHX YTJJl!X: l) bogs, which control the fixation of elements in the metal npHCyTCTBHe 3JJeMeHTOB B paCTHTeJJbHbTX OCTaTKaX H B organic compounds or sulfides; 4) degree of fracturing of ropHbTX nopo.uax, oi<aHMJTliTOI.UHe TopQJeHbTe 6onoTa; 2) the coal seams and 5) the presence and composition of HCTO'"IHHKH TTOBepXHOCTHbTX H TPYHTOBbiX BO.Il, KOTOpble mineral waters, which precipitate infiltrational minerals npHBHOCHJJH 3JJeMeHTbl B TOpcPliHHKOB; 3) KHCeJJHHHOCTb into the fractures of the coal beds. B .upeBHbiX TOPcPliHHKax, KOTOpal! KOHTpOJJHpyeT CBl!Jbl 3JJeMeHTOB C OpraHH'feCKHM Bei.UeCTBOM; 4) CTeneHb Tpe l.UHHOBaTOCTH yroJTbHbTX TTJJaCTOB; 5) npHCYTCTBHe H COC TaB MHHepaJJHJOBaHHbTX paCTBOpOB HJ kOTOpbiX B Tpe IUHHax yrOJJbHbTX TTJJaCTOB o6pa30BaJTHCb 3TTHTeHeTH'feC KHe MHHepaJJbl. Kortenski, J., Sotirov, A. 2000. Chalcophile elements in some Bulgarian coals. - Geologica Bale., 30, 3-4; 77-88 Key words: chalcophile elements; coal; Bulgaria 77 Introduction Sampling and experimental The occurrence and distribution of seven chal Digestion and analysis. cophile elements - Cu, Zn, As, Mo, Ag, Sn and A set of 718 core and channel samples of Pb in coal and coal shale from 13 Bulgarian coal and coaly shale were investigated. The coal basins and deposits are investigated (Fig. samples were ashed at 800 °C. The ash samples 1). The coal deposits investigated were: a) Lig were analyzed by Instrumental Neutron Activa nite from eight Neogene deposits were studied tion Analysis (INAA) and Inductively Coupled - Maritza-West, Stanyantzi, Belibreg, Sofia, Plasma Emission Spectrometry (ICP-AES). Karlovo, Samokov, Kyustendil, Oranovo and The results (Tables 1-5) were processed statisti Gabrovitza. b) The subbituminous coal from cally and the correlation coefficients between the Paleogene Pernik Basin. c) The bituminous the concentrations of the elements in the coal coal from Eocene Suhostrel and Cenomanian ash and the respective ash contents were deter Balkan Basins. d) The anthracite from the mined (Table 6). Svoge Carboniferrous Basin. The geochemical Determination of the affinities. peculiarities and distribution of these elements, Trace elements, which show a negative cor with the exemption of Sn, in Bulgarian coal relation coefficient with the ash content and from other basins and deposits were studied by their concentration decreases with the increas EcKeHa3H (1974), Eskenazy (1994, 1995) and ing of the ash content (Fig. 2) are determined as EcKeHa3H, MHH"'eBa (1986). elements with a higher organic affinity. Trace 0 M A N I A BUCK SEA OS ml2 4Skm Fig. 1. Location of the coal basins sampled for the present study: a - lignite; b - subbituminous coal; c - bituminous coal; d - anthracite; 1 - Maritza West; 2 - Stanyantzy; 3 - Belibreg; 4 - Sofia; 5 - Karlovo; 6 - Samokov; 7 -Gabrovitza; 8 - Kyustendil; 9 - Oranovo; 10- Pernik; II - Suhostrel; 12- Balkan; 13- Svoge 78 which are determined as elements with an inter mediate (mixed) affinity, have correlation coef ficients (negative or positive), whose values are not statistically reliable. In this case, the ele ment's concentration is saved almost constant with the change of the ash content (Fig. 4). Sometimes the correlation between ash and trace element contents is not enough to ensure the affinity, because some sulfides could be en riched in the ash-poor coals. The mineral form of the chalcophile elements is connected with :J) the sulfides. Kortenski, Kostova (1996) report 25 1-sn that the pyrite from Bulgarian coals very often E 2:20 associated with clay minerals in the ash-rich c"" 15 coals. The pyrite content also increases with the !! a 10 growing of the ash content. Therefore, the af u finity, determined by the correlation between ash and element contents are enough correctly. 20 00 100 Results and discussion Fig. 2. Plot of chalcophile elements concentrations in ash versus ash content in some studied basins. Copper 1 - Maritza West; 4 - Sofia; 6 - Samokov; 9 - Oranovo; 10 - Pernik Coal ash from the Sofia, Kyustendil, Samokov and Pernik basins exhibit Cu concentration elements, which show a positive correlation co (Table 1). The Cu content exceeds the Clarke efficient with the ash content, are determined by IO.u.osH\.f et al. ( 1985) from 5 to 7.5 times. as elements with an inorganic affinity. The ele The Cu concentration in the ash from the Kar ment concentration increases with the growing lovo, Oranovo and Belibreg lignite exceeds of the ash content (Fig. 3). Trace elements, nearly 2 times the same Clarke (Table 1) . The 1«l 1«l 120 120 ~m +.---~•~------~•~--_.. a.K1oo [100 c 00 12-/G a. 80 13-QJ ·----~-........- - ----i·l--- -· ~ ro ~ 60 8 «l c 8 40 20 20 1~~ k-k----~·~-------·._--~. o +-----~----.-----.---~----~ 0 20 00 100 0 +-----.---~----~----.----. 0 20 40 60 BO 100 2 3-lq ..____ _.• ..__- ------"~·~--......... E 1.5 a. c. -- 7-Sn ~ 1 ------------~ E 0 u 0.5 o+-----~----~----~----~--~ 0 20 40 60 80 100 o+-----~--~.----,----~----~ 0 20 40 60 80 100 Fig. 3. Plot of chalcophile elements concentrations in ash Fig. 4. Plot of chalcophile elements concentrations in ash versus ash content in some studied basins. versus ash content in some studied basins. 3 - Belibreg; 5 - Karlovo; 7 -Gabrovitza; 9 - Oranovo; 2 - Stanyantzy; 3 -Belibreg; 7 -Gabrovitza; 12 - Balkan; 11 - Suhostrel; 13 - Svoge 13 - Svoge 79 Table 1 Average content of the elements in the coal ash No Basins Number Cu Zn As Mo Ag Sn Pb of the ppm ppm ppm ppm ppm ppm ppm samples I Maritza-West 38 67 58 126 20 4.2 24 31 2 Stanyantzi 38 24 119 110 5.7 ND 21 71 3 Belibreg 39 86 51 172 1.7 1.7 l.l 20 4 Sofia 59 385 215 60 77 2.7 5.8 75 5 Karlovo 23 106 87 44 39 2.9 6.2 54 6 Samokov 31 340 424 150 11 1.9 2.4 116 7 Gabrovitza 40 40 51 125 7 0.8 1.2 52 8 Kyustendil 39 377 113 3.9 9 1.0 13 23 9 Ora novo 98 95 53 413 33 3.4 1.0 48 10 Pernik 35 237 301 339 19 0.3 2.7 101 11 Suhostrel 17 53 95 Ill 2.9 2.1 17 38 12 Balkan 26 52 91 91 17 1.5 8.4 25 13 Svoge 90 87 162 88 26 2.2 4.6 62 Clarke for lignite and subbituminous coal ash1 48 100 60 13 4.1 53 Clarke for bituminous and anthracite coal ash1 80 150 90 25 2.5 7.5 170 I - by IO~oBH'f et al.

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