Reconnaissance study of mineral matter and trace elements in Greek lignites

Chemical Geology, 76 (1989) 107-130 Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands

107

Reconnaissance study of mineral matter and trace elements in Greek lignites A.E. F O S C O L O S 1'*, F. G O O D A R Z I 1, C.N. K O U K O U Z A S 2 a n d G. H A T Z I Y A N N I S 2 IInstitute of Sedimentary and Petroleum Geology, Calgary, Alta. T2L 2A 7 (Canada) ZInstitute of Geology and Mineral Exploration, Athens 11527 GR (Greece) ( Received August 5, 1988; revised and accepted December 15, 1988)

Abstract Foscolos, A.E,, Goodarzi, F., Koukouzas, C.N. and Hatziyannis, G., 1989. Reconnaissance study of mineral matter and trace elements in Greek lignites. Chem. Geol., 76: 107-130. Mineral matter in low-temperature ashes, major oxides and trace elements were determined for twenty-eight selected lignite samples and their respective 1000°C ashes from various locations in Greece using X-ray diffraction, Xray fluorescence spectroscopy and INAA. Lignites ashed at lower temperature (150 ° C ) reveal the presence of quartz, feldspars, layer silicates, pyrite, gypsum, bassanite and anhydrite in all samples. In northwestern Greece (Epirus, Kozani, Florina and Ptolemais) calcite, siderite, magnesite, epsomite, hexahydrite, jarosite and meta-aluminite coexist with the common occurring minerals. Large variation in the concentration of major constituents in the 1000 ° C ashes is observed. SiO2 varies from 11.98% to 87.72%, A1203 from 4.53% to 23.36%, Fe~O3 from 3.01% to 39.72%, CaO from 0.55% to 43.05%, MgO from 0.18% to 9.17% and SO3 from 0.02% to 32.72%. Smaller variations are exhibited by Ti02, Na20, K20 and P20~. These variations are attributed to the depositional environment. High concentrations of Pb (548 ppm), Zn (2991 ppm), Ba (1520 ppm), As (1131 and 1675 ppm), Mo (565 and 712 ppm), W (191-420 ppm) and Sb (69 ppm) are reported in the 1000 °C ashes of the selected lignites from Serres and Drama, northern Greece. Samples from another location in northern Greece, Serres, yield > 5000 ppm U while in Drama (Dipotama) U concentration reaches as high as 17,600 ppm. The U enrichment of lignites in these locations is attributed to the leaching of this element from the superimposed U-bearing volcanic rhyodacitic rocks of Oligocene age. In southern Greece, Peloponnesus, lignite samples from Megalopolis, Xidias, Drossato and Vounargo show high F ranging from 154 to 218 ppm. Present results indicate that not only the wide variety and combination of elements that can be used to fingerprint lignitic basins but also the possibility of extracting such valuable elements from lignites and their ashes whenever the concentration and economics warrants such an undertaking.

1. Introduction Coal a n d c a r b o m i n e r i t e ( S t a c h , 1982 ) in coal s e a m s c o n t a i n m i n e r a l m a t t e r a n d t r a c e ele*Currently with the School of Mineral Resources Engineering, Technical University of Crete, P.O. Box 49, Chania, Crete, Greece.

m e n t s in v a r i o u s c o n c e n t r a t i o n s (Valkovic, 1983). T r a c e e l e m e n t s are a s s o c i a t e d e i t h e r w i t h organic ( m a c e r a l s ) or inorganic p o r t i o n s o f coal. Various a u t h o r s h a v e d i s c u s s e d e x t e n s i v e l y t h e a s s o c i a t i o n of t r a c e e l e m e n t s w i t h organic a n d i n o r g a n i c p o r t i o n of coals ( N e w m a r c h , 1953; H a w l e y , 1955a, b; G o l d s c h m i d t , 1958; Zubovic et al., 1961, 1964, 1966; G l u s k o t e r et al.,

108

A.B.FOSCOLOSET AL.

( YUGOSLAVIA •

jo"

I

~

km I

J

. . . .

,~3,4

1 9 , 2 0 , 2 1 ",'~

:::::::

"

.. r ~::~:::~/

17,1S~;--'~':.:~ f~Kava ~ ! i i ~ A "::::~i:i~. ib"~I 0 -::::::":"::::

I0,11

1 O0

BULGARIA ...p

"* j,.,.. ~,.,.°o° ::(~iF.16rina •

0

..

:

"

"':"

'~

• / exanrlt-n,'lnrHi~

"~o . . . . . . . . "

oo

I

Distribution

coal-bearing

of m a j o r basins

Z2 C

R

E

T

E

~

Fig. 1. Map of Greece showing location of lignite basins.

1977; Eskenazy, 1978, 1987; Finkelman et al., 1979; Kronberg et al., 1981; Nichols and D'Auria, 1981; Cecil et al., 1982; Landheer et al., 1982; Finkelman, 1983; Krejci-Graf, 1983; Goodarzi, 1985; Goodarzi and Cameron, 1987; R.N. Miller and Given, 1987). The concentration of elements in coals as influenced by mineralization, environment of deposition, age and coal rank has been reported by Nicholls (1968), Swaine (1971), Gluskoter et al. (1977), Goodarzi et al. (1985), Van Der

Flier(-Keller) and Fyfe (1985, 1987) and Goodarzi (1987a, b, c). Mineral identification can be used to delineate mining areas within a coal deposit thus improving the quality of mineable coal, while major and trace elements can be used either for reconstructing the paleoenvironment of a given coal basin or to study air, water and soil pollution. Concern is also generated about the effect of major and trace elements and mineral matter in the process of converting coal to other fuels

MINERAL MATTER AND TRACE ELEMENTS IN GREEK LIGNITES

109

such as gas, liquid and clean solid fuels (Gorin, 1981). As electric power plants become larger and boilers begin to operate at higher temperatures, problems of fireside boiler-tube fouling and corrosion become increasing severe. These problems are attributed to sulphur, chlorine, alkali metals and ash content of the coals (Crossley, 1967; Swaine, 1977; Reid, 1981). However, not all interest in mineral matter and trace elements in coal is generated because of its detrimental effect. Valuable elements such as Ge, U and Ti can be extracted from coals (Valkovic, 1983). Ge has been reported at 1.6% G e Q in ash from a Newcastle coal, England, and also from West Virginia in the U.S.A. (Goldschmidt, 1958), while lignites from North Dakota were treated as high-grade uranium ore (R.I. Miller and Gill, 1954). Uraniferous lignites from the U.S.A. contain on average 2.7 kg of U30s per ton of ash (Valkovic, 1983 ). There are more than sixty lignite-bearing basins in Greece. The most important are presented in Fig. 1. Extensive exploration, to date, has yielded 5.3.109 t* of reserves (Koukouzas, 1985). Sixty per cent of these reserves is mineable. Peat deposits totalling 4.3.109 m 3 are excluded from these reserves. Results of coal petrographic studies on a limited number of Greek lignites were reported by Cameron et al. (1984). The annual production of lignite in Greece exceeded 31" 10 ~t in 1985, out of which 29.6.106 t were consumed by sixteen power stations to generate 13,060 GW-hr. The latter represents 59% of the annual power production. It is estimated that by the year 1992 the annual production of electricity from the use of lignite will reach 75 %, while hydroelectric power and crude oil will contribute 17% and 8%, respectively (Public Power Corporation of Greece, 1983). Since the ash content of most lignitic deposits in Greece ranges between 30% to 45% the study of mineral matter and trace elements assumes an important role in respect to their use. As a

result this reconnaissance study was undertaken.

*1 t = 1 m e t r i c t o n n e = 103 kg.

2. General geological setting Economic deposits of Permocarboniferous coal have not been discovered yet in Greece because of unfavourable conditions. Small lenslike beds of non-economic significance have been found in three places (Koukouzas, 1978). Lignite and peat deposits of Tertiary and Quaternary age have been discovered. During these periods the most important lignite deposits were formed in intermontane grabens and basins (e.g., Ptolemais, Megalopolis, Florina). Some thin lignite beds which have considerable lateral extent were formed at coastal areas or in river deltas (Orestias, Atalanti, Katerini) (Koukouzas, 1978). Approximately 70% of the Neogene basins is intramontane while the remaining 30% is coastal which periodically were connected with the sea.

3. Experimental Twenty-eight lignite samples were collected throughout Greece (Fig. 1). Samples were obtained either as full channel samples of the coal seams or as a part of a seam located between two major partings or cores from boreholes. Samples were ground to < 100 mesh (150 /~m) for mineral matter and trace-element studies. Proximate and ultimate analysis were carried out following the procedures outlined by A.S.T.M. (1979). The results along with the calorific values are presented in Table I. Mineral matter and trace-element analyses were carried out following the procedure outlined by Goodarzi et al. (1985). Coal ashes prepared at 150°C (low-temperature ashing) were analyzed by X-ray diffraction. Volatile trace elements were determined on lignites by instrumental neutron activation analysis (INAA), while the non-volatile trace elements were determined on the 1000°C ashes either by X-ray fluorescence using the method of Trail and

Dipotama Dipotama Dipotama Zelio Thoknia Thoknia Platiana Xidias Drossato Vounargo

Kardia Ioannina Ioannina Pangeon

*~Carbominerite (after Cameron et al., 1984). *2By difference.

GK-13 GK-14 GK-15 GK-16 GK-17 GK-18 GK-19 GK-20 GK-21 GK-22 GK-23 GK-24 GK-25 GK-26 GK-27 GK-28

GK-12 Anatoliko

Age

Miocene Miocene Oligocene Oligocene Oligocene Pliocene Upper Pliocene Pliocene Pliocene Lower Pliocene Florina Lower Pliocene Kozani Lower Pliocene Ptolemais Upper Pliocene Epirus Pleistocene Epirus Pleistocene Serres Miocene Serres Miocene Serres Miocene Drama Oligocene Drama Oligocene Drama Oligocene Atalanti Pliocene Megalopolis Pleistocene Megalopolis Pleistocene Peloponnese Pliocene Kalavrita Pliocene Kalavrita Pliocene Peloponese Pleistocene

Katerini Katerini .1 Orestias Orestias Orestias Kozani Florina Kozani Kozani Florina

Location

Moschopotamos Moschopotamos Dilofo Dilofo Kyprinos Lava Anargyri Lava Lava Achlada

GK-11 Achlada

GK-1 GK-2 GK-3 GK-4 GK-5 GK-6 GK-7 GK-8 GK-9 GK-IO

Sample No.

48.0 56.0 42.0 18.0 23.0 23.0 24.0 13.0 17.0 23.2 32.0 43.2 27.0 29.0 22.0 15.0

20.0 44.89 47.30 48.88 50.70 53.50 48.00 40.00 24.30 26.10 33.40 35.10 30.70 34.18 46.20 42.10 37.82

48.10

48.30

44.70 36.50 43.90 49.60 47.00 63.00 48.70 49.60

32.0 31.2 32.8 50.0 52.0 40.0 48.0 53.0 46.0

39.20

20.4

18.40 29.30 27.80 15.00 3.00 9.00 2.00 45.50 26.20 43.20 48.60 56.50 36.10 27.10 29.10 43.70

17.10

34.80 36.71 23.40 23.32 33.70 43.50 43.00 58.00 30.20 47.70 23.40 56.30 12.80 29.72 26.70 28.80 18.48

17.40

20.80 74.40 8.40 29.00 14.50 11.90 24.90 4.50 20.00 14.70

34.30

40.00 46.90 34.50 41.60 38.50 28.10 32.50 31.30 35.70

H (%)

48.97 41.35 44.75 52.28 62.67 59.55 69.59 39.16 49.10 37.75 34.10 28.13 42.75 35.55 46.37 45.79

4.12 4.22 4.11 4.90 5.36 4.83 5.18 3.10 3.67 3.37 2.94 2.51 3.41 4.12 4.21 5.19

51.54 4.50

51.70 4.42

58.26 4.31 50.93 4.95 47.14 4.22 60.39 4.48 58.21 5.02 50.66 3.71 63.78 5.88 51.47 4.43 56.89 3.84

Moisture Volatile Fixed Ash C (%) matter carbon 750°C (%) (%) (%) (%)

Localities, age, per cent moisture, proximate and ultimate analysis on dry basis and calorific values

TABLEI

0.57 1.22 0.44 1.32 0.41 0.51 0.82 0.57 0.63 0.84 1.10 1.01 1.13 0.61 1.27 0.53

1.34

0.52

1.40 1.07 0.89 1.11 1.24 1.49 0.32 1.00 1.30

N (%)

0.99 5.21 6.38 4.29 1.82 2.92 6.29 3.94 9.45 0.73 3.19 2.60 1.58 0.88 2.13 2.95

2.30

1.68

4.05 3.71 4.47 1.06 1.73 0.97 1.93 0.94

1.98

Stool (%)

4,778 4,649 4,397 3,617 4,108 4,961 5,826 5,655 6,594 3,343 4,307 3,069 2,956 2,479 3,755 2,910 4,028 4,082

24.28 17.40 24.62 15.70 26.95 21.20 20.12 23.21 26.74 25.89 16.42 12.83 13.45 19.21 17.77 16.35 19.63 34.34 21.32 7.34

18.40 26.80 24.20 14.00 3.00 6.30 1.70 40.40 23.70 38.10 40.90 49.40 31.50 24.50 24.70 38.20

5,347 5,519 4,253 5,586 5,292 4,549 6,388 4,719 5,060

Ash Calorific 1000°C value (%) (kcal. k g - ' )

13.45 20.60 74.40 32.42 6.60 18.94 25.10 19.75 9.80 23.77 10.70 23.91 18.50 26.15 2.90 25.87 15.30 27.03 13.00

0 *2 (%)

O

O

MINERAL MATTER AND TRACE ELEMENTS IN GREEK LIGNITES

111

Lachance (1965) or by neutron activation analysis (NAA). The advantage of NAA is discussed by Lenihan and Thomson (1969) and the obtained results were compared with certified reference material such as N.B.S. coals, fly ash, sediments, orchard leaves, oil shales and others. During various ashing procedures, variable proportions of the total sulphur were volatized while others were fixed in the final 1000 °C ash. These various proportions were determined by LECO ® apparatus, as outlined by Foscolos and Barefoot (1970). Cluster analyses of trace elements in ashes were performed using the method described by Labont~ and Goodarzi (1985). The elements with standard deviation of > + 20 and also elements which are reported as "less-than" values were not included in cluster analyses.

(Table II). Carbonates are present in most of the lignites in north-central and northwestern Greece with or without sulphates such as hexahydrite (MgSO4-6H20), meta-aluminite [A12SO4 (OH) 4"5H20 ], jarosite [ KFe3 (SOt) 2" (OH)6] and baryte (BaSOt). Amphiboles are present in one sample from northeastern Greece and its origin may be traced to the adjacent granitic rocks. Diaspore is observed in one sam~ ple (No. 8), anatase in three samples (Nos. 18, 19 and 28; Table II).

4. Results a n d d i s c u s s i o n

Locations of the samples, indicated in Fig. 1, and mineralogic, organic and inorganic chemical data are presented in Tables I-VI. Lowtemperature ashes of lignites indicate presence of quartz, clay minerals, carbonates, sulphates, sulphides as major constituents while amphiboles, diaspore, talc and glaucophane are very rare (Table II). Major elements show large variations depending upon the locality (Table III). The concentration of trace elements in lignites and lignitic ashes is presented in Figs. 2 and 3 and Tables IV and V. The variation of certain elements in lignites and lignitic ashes as a function of their organic or inorganic affinity is shown in Figs. 7 and 8, while the similarity index between elements in lignitic ashes is presented in Fig. 9. 4.1. Minerals Greek lignites contain quartz, layer silicates, and sulphates that are usually associated with coal. Sulphides are present in most samples

4.2. Major elements Analysis of low-temperature ashes yields large variations in the concentration of major elements. SiO2 varies from 11.98% to 87.72%, A1203 from 4.53% to 23.36%, Fe203 from 3.01% to 39.72%, CaO from 0.55% to 42.95%, MgO from 0.18% to 9.17% and SO3 from 0.02% to 32.72%. Ti02 varies from 0.03% to 1.06%, Na20 from 0.00% to 2.31%, K20 from 0.23% to 2.99% and P205 from 0.03% to 2.64% (Table III). 4.3. Elemental concentration of volatile elements in coals The method described by Gluskoter et al. (1977) concerning enrichment or depletion of non-volatile elements in coal was modified. An element was considered enriched if its concentration in the ash was two times that of the Earth's crust (Clarke's value; Mason and Moore, 1982) and depleted if its concentration was less than two times. As is concentrated in most samples. High As contents are encountered in samples 16-21 from northeastern Greece. Samples from central and southern Greece show lower concentration (samples 25-28, Table IV). High F concentrations (132-258 ppm) are encountered in samples from southern Greece (Nos. 23-28), indicating the influence of a paralic environment or an environment with high salinity (Krejci-Graf, 1983). The same is true from bromine (Goo-

A.E. F O S C O L O S

112 DISTRIBUTION

DISTRIBUTION OF CI IN LIGNITES

OF As IN LIGNITES

2OO

220" IOO.

150

~100-

ID050-

60,

,

,

,

,

,

,

,

,

,

,

,

,

2O

DISTRIBUTIONOF 1IN LIGNITES

D I S T R I B U T I O N OF Br IN LIGNITES IO 86-

~ 1 cL

0

0

5

0

0

42o

DISTRIBUTION

DISTRIBUTIONOF U IN LIGNZTES

OF Ir IN LIGNITES 5O

5064 pjn

30" 26" 22-

~ 30 20

14I0-

Io

6-

o

2

DISTRIBUTION

O F Se IN L I G N I T E S

DISTRIBUTION

OF V IN LIGNITES

DISTRIBUTION

OF Hg IN LIGNITES

24O

200 160

~ 120 8e 40

0 DISTRIBUTION

6

0

0

O F B IN L I G N I T E S

~

E 3oo

~ 200 100

0

1 3

5

7

9 ii 1 3 1 5 1 7 1 9 2 1 2 3 2 5 2 7 No ol sample

Fig. 2. Volatile a n d non-volatile trace elements in lignites.

i

No. of sample

ET A L

MINERAL MATTER AND TRACE ELEMENTS IN GREEK LIGNITES DISTRIBUTION OF As CONTENT

DISTRIBUTION

0.50.4-

0.20

Cs

DISTRIBUTION OF Cr CONTENT

CONTENT

20-

I.,I-

0.8-

OF

2A

1.6-

12-

113

,,

1612040

DISTRIBUTION OF Co CONTENT

DISTRIBUTION OF Cu CONTENT

DISTRIBUTION

OF Au CONTENT

200

340150300 -

150~

250 -

22o-

100-

IOO"

,4 ~803407 50-

50 IOOt 60

I

20

I

DISTRIBUTION OF Mn CONTENT

0

DISTRIBUTION OF Mo CONTENT

DISTRIBUTION OF Ni CONTENT 3.2, 2.8-(

660

~

2.4-] ,7-4

500 ~

466

1.5 4

300"

1.2-]

200"

os-I

100i

,

~

i

i

i

DISTRIBUTION

r

,

i

i

l

0.,~-f

o ,~'~,~T

r

OF Rb CONTENT

. ,.~.-~--~-~,

DISTRIBUTION

oF

DISTRIBUTION OF U CONTENT

OF W CONTENT 1.4-

150

17600p.p.I,

1.23OO

100-

~_ 0 . 0 -

,': 2O0 50"

~ 0.8o. 0 . 4 -

tO0

0.2-

0

C,

DISTRIBUTION

OF V CONTENT

DISTRIBUTION 14-[

1.6-

OF Zn CONTENT

i

i

,

,

,

DISTRIBUTION

,

i

r

,

,

,

J

,

OF Pb CONTENT

6O0

299t p.p.m,

1,6-

50O

14,tOO i

12-

I~ 0.8~. 0.60.4~ 0.20

i

E

.8

~, d

0.6

300 2oo

O.l Ioo

O.

,

3

,

5

r ,

7

9

,

,

r ,

,

,

,

,

,

IF 13 15 I1 19 21 23 25 27 No. of sample

Fig. 3. T r a c e e l e m e n t s in 1000 ° C lignitic a s h e s .

o No. of sample

; ~ ~ ; ,', ;3 ,'s ,', ,; ;, 2'3 h 27 NO, of sample

114

A.E. FOSCOLOS ET AL.

T A B L E II

Per cent low-temperature ash and semiquantitative mineralogical analysis Sample No.

Lowtemperature ash

Silicates quartz

Carbonates feldspar

~ 150 ° C

mixed layered

illite

11

GK-1

27.5

19

20

GK-2 GK-3

86.2 15.4

18 15 .1

25

GK-4

35.O

14

GK-5

18.9

GK-6

17.2

GK-7 GK-8

talc

kaolinite

chlorite

8

10 ~

16

20

13

21

21

4 10 7 *2

calcite

16

8

7 30 20

15

20

8

38.8 5.1

21 20 .1

19

GK-9

27.6

23

GK-IO GK-11 GK-12 GK-13 GK-14 GK-15 GK-16 GK-17 GK-18 GK-19 GK-20 GK-21 GK-22 GK-23 GK-24 GK-25 GK-26 GK-27 GK-28

20.4

26

19

7

7

17

23.4

29

tr.

18

11

9

6

21.7

21

6

15

5

6

tr.

26 14

6

14 5 *2

13

7

6 *2

7

20

28.4

40

38.9

22

32.5

13

20.1

8

24 15

4.4

3

10

19

6

tr.

23

tr.

86

16 10

10

47.7

tr. 4

34.6

32

11 45

13 12 *2

52 47

50.9

39

32.4

49

33.7 47.6

tr.

24

14 17

21

16

65.5

carb. apatite

19

69

43

magnesite

7

3.1

50.0

siderite

16

13

11.4

59.5

dolomite

tr.

30 20

8

tr. 7 *2 8 *2

28

15

32

tr. tr.

26 18

15 14

44

8

24

tr.

10

8 tr.

carb. apatite -- carbonaceous apatite; tr. = trace. * 1Tridymite ' *2Kaolinite and chlorite.

darzi, 1987a, b). C1 and V, however, are depleted in all samples (Table IV). Boron concentration has been used to determine the paleosalinity of the depositional environment (Degens et al., 1958; Swaine, 1962, 1971, 1975; Couch, 1971; Bohor and Gluskoter, 1973; Chen-Lin-Chou, 1984; Lindahl and Finkelman, 1986; Goodarzi, 1987a, b). Two lignite samples from northeastern Greece, Nos. 3 and

5, have high B concentration, 167 and 444 ppm, respectively, indicating marine-influenced environment while the remaining lignites have < 100 ppm B (Table IV). The latter, however, does not imply that the remaining samples were deposited in a freshwater environment. Lignite samples from Peloponnesus (southern Greece), Nos. 23-28, have high F concentration. The latter, though low in B concentration has high Br,

MINERAL MATTER AND TRACE ELEMENTS IN GREEK LIGNITES

115

Miscellaneous

Sulphur-bearing minerals

pyrite gypsum anhydrite bassanite epsomite hexa- metajarosite barite ammonium amphi- diaspore anatase unknown hydrite aluminate iron boles sulphate 6

10 3

7 13 8 4

9 9 41

3 13 4 6 4

17 7 8

5 6 19 18

10 31

22

13 23 20 30 13 8 7 20 13 18 10

4 11 17

9

12 6

4 6

18

21 5

tr. 23

3

14

19

7

18 8 11

tr. tr. 14

C1 and F concentrations, 172, 166 and 132 ppm, respectively. As a result, B concentration should be used cautiously as a paleosalinity indicator as stated by Gluskoter et al. (1977). Part of total B and F concentration can be attributed to the concomitant 2:1 layer silicates (Dewis et al., 1972, and Rimsaite, 1967, respectively). Uranium concentration in general, are higher than Clarke's value except in samples 3-5, 8, and 10. However, the concentrations range from less than two times the Earth's content up to 2813 times (sample 21 ). U enrichment in the samples 21 and 23 is attributed to leaching of this element from the overlying ignimbrites of

10

Oligocene age and its subsequent trapping by the organic matter*. 4.4. Elemental concentration in coal ashes

The 1000°C ashes of samples 1 and 2 from Katerini (northern Greece), yield Ni concentrations between 1400 and 3000 ppm and Cr be*Detailed X R D a n d S E M w i t h a K E V E X ® attachment recrystals of autunite, (Ca, S r ) (UO2)2 (PO4)2"10.6H20 and metauranocircite Ba (UO2)2 (PO4)2"8H20 in the uranfferous lignites (unpublished data

vealed

by the senior author).

116

A.E. FOSCOLOS ET AL.

TABLE III Major elements in 1000°C lignitic ashes Sample No.

SiOe

AI20~ T i O 2 Fe203 CaO

MgO

Na20

K20

BaO

P 2 0 5 SO3

Losson ignition .1

Total

GK-I GK-2 GK-3 GK-4 GK-5 GK-6 GK-7 GK-8 GK-9 GK-IO GK-11 GK-12 GK-13 GK-14 GK-15 GK-16 GK-17 GK-18 GK-19 GK-20 GK-21"2 GK-22 GK-23 GK-24 GK-25 GK-26 GK-27 GK-28

31.98 52.68 30.27 48.87 23.14 15.45 35.53 21.79 24.49 26.04 48.17 44.56 32.81 31.21 24.59 33.81 11.98 22.95 50.33 87.72 47.43 57.38 51.83 57.52 51.18 50.93 44.04 49.34

16.99 23.29 16.23 23.02 12.26 7.29 15.81 11.23 14.20 12.53 26.10 19.43 14.97 13.66 11.37 19.32 7.06 12.28 21.10 4.53 10.57 22.34 20.82 23.36 19.57 19.61 17.81 16.78

6.43 9.71 2.92 2.93 5.56 5.58 4.08 4.35 3.75 2.82 3.21 4.35 5.86 1.56 1.51 2.25 2.01 5.97 0.74 0.18 3.68 6.74 2.42 1.98 4.20 3.52 4.55 3.39

0.21 0.00 0.21 0.16 2.31 0.00 0.32 0.11 0.00 0.13 0.05 0.65 0.12 0.08 0.03 0.27 0.50 1.24 0.16 0.36 0.56 0.00 0.42 0.24 0.00 0.00 0.24 0.45

1.29 1.09 0.86 1.55 1.00 0.13 0.15 2.69 0.14 0.57 0.28 0.33 0.66 0.47 0.76 0.80 0.23 1.04 2.04 2.99 1.64 1.48 1.96 2.46 2.62 2.16 2.69 2.42

0.17 0.04 0.05 0.03 0.28 0.07 0.10 0.11 0.09 0.03 0.06 0.05 0.04 0.08 0.10 0.08 0.08 0.14 0.08 0.02 0.07 0.06 0.08 0.05 0.14 0.15 0.20 0.04

1.29 0.08 0.05 0.07 0.24 0.13 0.15 2.64 0.14 0.57 0.28 0.33 0.66 0.46 0.29 0.06 0.03 0.33 0.10 0.03 0.43 0.08 0.41 0.16 0.26 0.18 0.11 0.29

0.35 0.15 0.30 0.10 0.20 0.75 0.30 0.50 0.40 0.40 0.23 0.25 0.30 0.15 0.25 0.20 0.15 0.20 0.36 0.15 0.25 0.10 0.15 0.15 0.30 0.25 0.25 0.20

99.74 99.23 99.20 99.48 99.35 99.64 100.74 100.98 99.81 100.25 99.19 100.21 100.37 99.76 99.16 100.67 100.43 100.51 99.01 99.77 100.08 99.75 100.24 99.41 100.22 99.59 100.27 100.37

0.59 0.99 0.10 0.07 0.63 0.33 0.87 0.41 0.50 0.59 1.06 0.93 0.67 0.62 0.52 0.77 0.07 0.53 0.73 0.13 0.88 0.03 0.07 0.04 0.08 0.78 0.68 0.75

15.61 9.29 39.72 18.23 14.48 9.31 10.72 6.1 11.63 11.12 9.97 9.58 7.18 14.39 9.78 21.74 18.12 26.79 17.89 3.01 30.83 6.36 10.77 7.16 8.41 10.67 14.98 9.74

14.44 1.61 5.37 4.20 19.41 42.95 18.58 27.48 25.31 32.59 6.93 11.51 25.86 20.01 25.24 12.63 27.49 15.55 5.41 0.55 1.65 4.93 8.54 5.54 9.64 8.69 8.73 9.23

10.39 0.30 3.82 0.31 19.34 17.65 14.13 22.76 19.16 12.86 2.86 8.24 11.24 17.05 24.72 8.66 32.72 13.48 0.07 0.10 0.02 0.31 3.39 0.75 3.82 2.65 5.99 7.74

*1Loss of H20 + on 1000°C ash. *20203 = 2.07%. t w e e n 1800 a n d 34000 p p m . T h e s e high c o n c e n t r a t i o n s are a t t r i b u t e d to a n e n r i c h m e n t of t h e M o s c h o p o t a m o s b a s i n b y w a t e r seeping f r o m a d j a c e n t p e r i d o t i t e s a n d serpentinites, h o s t i n g c h r o m i t e a n d nickel deposits ( Z a c h o s a n d M a r atos, 1965; K o u k o u z a s a n d Kouvelos, 1973). T h e 1000 °C ashes of lignites Nos. 16-21 from Serres a n d D r a m a ( n o r t h e r n Greece) c o n t a i n high c o n c e n t r a t i o n s of P b ( 548 p p m ), Zn (2991 p p m ) , B a (1520 p p m ) , As ( 1 1 3 1 - 1 6 7 5 p p m ) , M o (565-712 p p m ) , W ( 1 9 1 - 4 2 0 p p m ) a n d Sb (69 p p m ) . T h e s e high c o n c e n t r a t i o n s are due to the fact t h a t t h e lignite s e a m s o c c u r in a drainage basin, in w h i c h a c c u m u l a t e w a t e r s c o m i n g f r o m t h e a d j a c e n t rocks, c o n t a i n i n g

m e t a l deposits ( A n a s t o p o u l o s a n d K o u k o u z a s , 1984). E l e v a t e d c o n c e n t r a t i o n s of U are e n c o u n t e r e d in s a m p l e s 17 a n d 18, f r o m Serres, with 516 a n d 563 p p m , respectively, a n d s a m p l e s 19 a n d 21, f r o m D i p o t a m a , w i t h 1,073 a n d 17,600 p p m , respectively. T h e U e n r i c h m e n t in t h e s e locations is a t t r i b u t e d to overlying i g n i m b r i t e s o f Oligocene age. T h e c o n c e n t r a t i o n s of n o n - v o l a t i l e e l e m e n t s in m o s t lignitic ashes are h i g h e r t h a n C l a r k e ' s values with t h e e x c e p t i o n of Hf, Rb, Sc a n d T a (Table V). T h e c o n c e n t r a t i o n s of r a r e - e a r t h e l e m e n t s ( R E E ' s ) in coal ashes are also higher t h a n C l a r k e ' s values with e x c e p t i o n of T m . T h e

117

MINERALMATTERAND TRACEELEMENTS IN GREEKLIGNITES TABLE IV

Trace elements in ppm (unless otherwise indicated) in lignites Sample No.

As

Br

Cl

I

Ir (ppb)

Se

U

V

B

F

Hg

Earth's crust

1.8 30.3 24.5 41.0 20.7 57.1 7.3 5.7 13.4 207.0 6.4 20.0 6.1 22.2 29.8 63.4 124.0 34.0 79.3 38.0 13.2 90.3 9.9 14.0 9.6 7.1 6.3 16.6 6.4

2.5 3.7 2.6 6.0 5.6 70.2 16.3 19.0 2.0 8.2 20.8 5.4 10.9 18.9 26.3 20.2 3.6 1.3 3.8 1.4 1.1 2.1 3.8 35.7 54.9 9.0 8.8 25.0 172.0

130.0 37.8 < 39.3 234.0 38.7 93.9 57.6 121.0 38.1 41.7 74.2 51.2 49.2 67.9 134.0 85.9 36.2 64.8 30.6 23.9 43.3 < 136.0 24.4 106.0 104.0 21.3 57.2 30.4 166.0

0.5 < 1.0 < 3.6 <0.7 < 1.3 <3.7 8.1 3.4 0.6 1.9 8.0 < 1.1 2.4 5.6 4.1 5.8 < 0.9 0.7 < 0.9 <0.6 < 0.7 < 8.3 1.3 4.1 3.3 < 1.2 < 6.1 < 2.0 9.6

0.001 < 6.4 < 12.8 <4.0 < 5.7 <4.1 < 3.4 <5.2 < 2.9 < 4.6 <3.8 <4.7 < 4.5 < 4.5 < 5.7 <5.4 < 5.0 <2.3 < 4.0 <3.3 < 4.5 30.4 < 7.5 <6.5 <8.2 < 6.5 < 6.1 < 5.9 <6.7

0.05 4.1 5.9 <0.9 2.3 1.7 < 0.6 <1.1 0.8 1.7 <0.9 1.3 1.8 1.5 4.4 8.0 1.0 2.6 5.2 <0.6 < 1.1 < 3.2 3.2 3.0 11.1 8.8 3.4 6.0 2.1

1.8 17.0 19.0 1.3 3.0 1.1 4.5 4.2 1.0 6.7 1.0 10.6 14.8 17.3 14.4 12.7 13.5 13.1 34.0 19.8 3.7 5064 24.7 4.6 10.5 4.8 2.6 3.4 3.4

135.0 74.3 244.0 11.3 132.0 19.6 10.7 58.4 17.3 33.0 12.1 46.7 101.0 96.7 68.0 81.2 60.5 8.2 134.0 10.5 17.8 n.d. 123.0 70.9 136.0 72.1 66.5 50.6 63.6

10 43 22 167 99 444 22 11 12 18 32 22 12 95 16 20 21 18 10 20 17 8 25 27 29 73 20 41 45

625 217 118 78 159 79 40 79 100 60 78 118 118 135 99 80 40 60 60 36 35 82 138 199 258 218 154 203 132

0.08 <0.01 ~<0.01 0.03 ~0.01 ~<0.01 0.20 0.13 0.20 0.06 0.15 0.07 0.03 0.06 0.03 0.07 0,04 4,06 0.09 0.05 0.05 0.06 ~<0,01 0.05 ~0.01 ~<0.01 0.05 0.05 0.06

GK-1 GK-2 GK-3 GK-4 GK-5 GK-6 GK-7 GK-8 GK-9

GK-IO GK-11 GK-12 GK-13 GK-14 GK-15 GK-16 GK-17 GK-18 GK-19 GK-20 GK°21 GK-22 GK-23 GK-24 GK-25 GK-26 GK-27 GK-28

n.d. = high uranium concentration causes difficulty in the analysis.

latter is depleted in all coal samples except in the lignitic ashes of samples 19 and 21 where the concentration was 7.6 and 17.1 higher than Clarke's value. The high U concentration in sample 19, 1073 ppm is accompanied by unusually high concentrations of Ce, 280 ppm; Tb, 5.92 ppm; Tm, 3.81 ppm; Yb, 30.1 ppm; Ho, 149 ppm; (Table V) and S, 6.33% (Table I). The same is true for sample 21. In both the abovementioned samples sulphate minerals are absent. All studied samples contain Ba, Cr, Cu, Zn, Mn, Ni and Zr concentrations over 100 ppm

(Table V). These values are within the ranges reportedby Swaine (1962) (Fig. 4) with exception of two samples which are enriched in Ni and Cr. Ti, Sc, V, Co, La, Y and Mo are usually within the normal ranges of concentration. However, Mo concentrations in samples 16-18, from Serres (northeastern Greece) are 2 to 9 times higher than those reported for the "rich" Newcastle coal ash (Table V). This enrichment can be attributed to leaching from the surrounding rocks which are rich in this element (Zachos and Maratos, 1965), and subsequent deposition in the lignite seams.

Earth's crust

0.2 1.8 425 0.2 3 100 25 55 15 4 3 950 1.5 75 90 22 0.05 0.07 375 2 7.2 1.5 1.8 135 33 70 135 13 60 3 1.2 1.2 30 0.5 28 6 0.9 0.5 3.4

Element

Sb As Ba Cd Cs Cr Co Cu Ca Au (ppb) Hf Mn Mo Ni Rb Sc Se Ag Sr Ta Th W U V Y Zn Zr Pb Ca* Dy* Eu* Ho* La* Lu* Nd* Sm* Tb* Tm* Yb*

7.8 130.0 1,591.0 <2.5 9.6 1,863.0 72.1 134.0 16.1 51.0 2.8 381.0 25.1 1,472.0 97.1 39.9 <2.5 <4.4 781.0 0.9 14.4 12.2 95.1 410.0 91.0 188.0 213.0 70.0 95.0 14.7 2.3 7.6 47.6 2.3 39.0 10.4 2.3 1.1 8.4

GK-1

2.0 22.5 368.6 <1.9 8.0 3,444.0 125.0 147.0 32.0 12.2 3.4 359.0 3.7 3,046.0 66.5 42.3 <2.3 <4.0 76.0 1.2 11.7 3.1 26.5 361.0 34.0 229.0 134.0 20.0 74.4 7.3 1.8 2.5 37.3 0.9 31.5 7.1 1.0 0.5 3.5

GK-2

17.4 403.0 447.6 <2.9 13.6 141.0 45.6 179.0 23.7 191.0 2.3 669.0 59.3 481.0 53.8 14.5 <2.5 <3.8 833.0 2.4 26.1 145.0 18.4 158.0 83.0 112.0 210.0 184.0 102.0 9.4 1.7 3.3 56.9 1.3 36.2 7.7 2.1 <0.5 5.2

GK-3

4.6 35.7 314.1 <1.8 21.7 110.0 27.8 146.0 24.9 54.8 2.8 523.0 25.7 252.0 152.0 19.3 <2.0 <3.5 479.0 1.6 31.7 14.3 12.3 217.0 44.0 60.9 163.0 79.0 84.7 6.4 1.4 1.9 45.6 0.9 37.0 6.8 1.0 0.4 3.8

GK-4

9.1 301.0 2,393.0 <3.2 15.3 118.0 26.5 144.0 51.2 43.5 3.0 4,128.0 19.9 515.0 34.8 18.2 <3.0 <3.4 2,000.0 0.9 13.4 9.8 9.5 135.0 52.0 111.0 432.0 83.0 51.7 7.5 1.4 2.2 22.8 1.3 23.9 5.9 1.5 0.5 5.5

GK-5

Trace elements (in ppm, unless otherwise indicated) in IO00°C ligniticashes

TABLE V

9.7 63.5 853.0 <1.9 1.3 115.0 31.7 93.0 37.7 10.5 1.8 618.0 13.2 104.0 20.7 10.3 <3.1 <2.7 515.0 2.2 6.2 6.5 44.3 107.0 26.0 76.6 144.0 38.0 76.0 5.9 1.5 6.4 29.0 1.0 28.0 6.1 1.2 <0.3 2.8

GK-6

4.1 23.5 852.1 <1.9 5.3 234.0 34.6 220.0 29.3 67.9 2.2 1,172.0 21.5 229.0 33.3 20.7 <3.0 <3.4 367.0 1.6 17.0 3.0 21.1 267.0 38.0 92.9 143.0 50.0 122.0 8.8 1.7 3.7 46.0 1.4 42.9 9.2 2.2 0.7 5.4

GK-7

49.5 325.0 810.0 <2.9 3.8 182.0 33.2 187.0 40.3 181.0 2.0 783.0 18.8 89.0 31.4 10.4 <2.6 <3.1 441.0 2.0 10.7 14.8 30.9 523.0 45.0 128.0 134.0 209.0 216.0 10.1 3.1 5.8 81.1 1.0 70.9 14.7 1.8 <0.4 3.6

GK-8

13.1 752.0 973.9 <2.7 5.2 181.0 21.9 349.0 36.6 19.0 2.7 1,055.0 12.8 131.0 50.9 16.2 <3.0 3.3 450.0 1.5 13.1 4.3 42.6 193.0 39.0 141.0 152.0 98.0 108.0 8.0 2.1 5.5 47.6 1.1 40.3 9.1 1.1 <0.5 3.8

GK-9

3.9 44.3 192.5 <2.6 3.4 93.3 17.6 96.0 30.9 10.8 2.7 1,803.0 37.6 101.0 55.6 11.8 <2.9 <2.8 423.0 2.0 9.6 11.6 8.8 85.1 23.0 139.0 174.0 40.0 74.3 4.2 1.4 2.0 38.3 0.6 29.7 6.1 0.8 <0.3 2.4

GK-IO

7.4 78.1 804.7 <3.3 13.3 211.0 53.3 156.0 47.3 21.6 3.6 611.0 73.1 198.0 181.0 19.3 <3.1 <3.4 485.0 2.8 33.7 36.6 61.9 257.0 57.0 78.4 212.0 121.0 166.0 9.2 2.4 7.8 84.2 1.2 64.0 11.5 1.6 0.9 4.7

GK-11

7.4 35.1 624.4 <2.2 5.2 488.0 31.9 176.0 15.9 54.2 4.2 322.0 28.6 ~ 651.0 101.0 23.8 <3.2 <4.0 239 1.7 13.7 6.7 97.5 348.0 46.0 57.1 186.0 65.0 82.8 8.2 1.8 11.7 38.7 1.1 37.0 7.4 1.7 <0.6 4.2

GK-12

5.7 104.0 616.0 3.1 8.2 591.0 17.7 140.0 17.7 5.0 3.0 304.0 18.0 453.0 58.5 14.9 3.1 <3.2 705.0 1.7 12.1 7.0 92.8 286.0 24.0 98.4 227.0 57.0 63.6 4.6 1.2 11.9 31.0 0.7 26.2 5.0 0.7 <0.4 2.4

GK-13

10.5 105.0 892.1 <2.3 5.6 218.0 20.2 191.0 <54.0 38.7 4.3 1,284.0 27.0 155.0 49.6 14.6 <3.0 <3.4 843.0 1.5 10.7 3.4 58.1 252.0 41.0 151.0 276.0 31.0 76.7 5.5 1.8 8.0 51.3 0.9 40.6 8.0 1.4 <0.6 3.8

GK-14

oo

6.9 225.0 522.0 <3.2 6.2 255.0 29.2 355.0 26.2 50.8 1.6 881.0 124.0 227.0 34.5 13.8 <2.9 <3.2 1,155.0 1.0 8.1 < 2.6 55.4 327.0 28.0 130.0 244.0 31.0 47.8 5.5 1.2 7.5 32.5 0.8 27.4 5.4 0.8 <0.6 2.7

GK-15

14.2 856.0 934.1 <4.8 10.2 249.0 40.7 274.0 37.0 17.4 0.9 481.0 134.0 396.0 93.8 30.0 <2.4 <4.6 445.0 1.5 19.9 9.7 98.2 478.0 52.0 208.0 98.0 76.0 98.2 9.4 1.8 13.0 33.8 1.2 32.2 7.6 1.0 <0.7 5.2

GK-16 52.1 1,131.0 1,520.0 68.0 <1.0 126.0 118.0 201.0 < 21.9 17.5 0.7 1,415.0 565.0 512.0 <22.2 6.192 <2.6 <3.5 239.0 0.6 2.2 191.0 516.0 215.0 46.0 2,991.0 65.0 324.0 21.2 5.8 1.6 65.4 < 4.9 2.0 20.7 2.6 0.6 <0.8 4.5

GK-17 68.6 1,045.0 1,360.0 <4.8 17.1 330.0 74.0 344.0 39.6 <6.5 2.9 1,081.0 712.0 444.0 55.2 23.7 <4.7 6.0 792.0 3.5 ]7.9 420.0 563.0 1,900.0 45.0 253.0 202.0 548.0 47.4 8.5 2.1 73.6 < 5.9 2.4 27.4 4.4 1.5 <0.6 5.9

GK-18 15.0 1,675.0 1,880.0 <10.0 23.1 221.0 38.0 350.0 200.0 45.7 6.3 1,279.0 154.0 246.0 121.0 79.1 <3.1 <5.3 332.0 2.2 97.0 97.2 1,073.0 475.0 298.0 511.0 298.0 476.0 280.0 41.7 8.4 149.0 65.8 7.9 91.3 24.1 5.9 3.8 30.1

GK-19

n.d. = high u r a n i u m concentration causes difficulty in the analysis. *Rare-earth element.

Sb As Ba Cd Cs Cr Co Cu Ca Au (ppb) Hf Mn Mo Ni Rb Sc Se Ag Sr Ta Th W U V Y Zn Zr Pb Ce* Dy* Eu* Ho* La* Lu* Nd* Sm* Tb* Tm* Yb*

Element

T A B L E V (continued)

7.4 50.9 258.4 <2.1 13.3 49.4 2.2 32.0 11.5 32.3 1.1 59.3 8.4 <59.9 142.0 5.6 <1.0 <1.5 90.0 0.3 5.8 < 2.8 11.3 45.6 34.0 27.1 71.0 50.0 13.9 3.0 0.4 1.6 7.0 0.6 4.9 1.3 0.4 0.5 3.3

GK-20 4.5

8.0 40.0 168.0 86.0 159.0 <40.0 4.4 608.0 n.d. 57.0 95.3 3.5 <9.1 <5.2 n.d. 1.2 7.4 n.d. 17,600.0 569.0 28.0 62.9 154.0 119.0 <431.0 7.4 2.1 n.d. n.d. n.d. <275.0 n.d. < 0.8 8.8 9.8

n.d. n.d. n.d.

GK-21 2.8 21.7 683.4 <2.7 9.3 760.0 42.4 111.0 23.5 28.0 4.2 239.0 15.9 987.0 92.1 35.5 <2.8 <3.8 185.0 1.5 11.3 2.8 65.9 344.0 37.0 124.0 150.0 26.0 78.3 7.6 1.8 4.9 36.2 1.2 34.2 7.2 1.1 0.6 3.8

GK-22

6.3 29.7 699.7 <1.8 9.6 236.0 24.7 165.0 30.9 15.3 4.8 531.0 10.1 226.0 121.0 20.0 <2.8 <3.3 549.0 1.8 14.1 < 2.0 11.8 183.0 38.0 110.0 251.0 66.0 86.8 7.0 1.6 2.0 50.0 0.9 39.4 7.6 1.3 0.6 3.6

GK-23 5.2 20.2 486.7 <2.8 12.7 351.0 52.9 194.0 29.9 22.0 5.6 319.0 33.4 215.0 148.0 24.8 <3.0 <3.6 239.0 2.0 16.3 2.6 22.7 282.0 47.0 185.0 213.0 56.0 91.7 9.2 2.1 3.2 60.9 1.2 42.9 9.2 1.5 0.7 4.4

GK-24 2.6 21.2 1,143.0 <1.8 9.9 424.0 40.4 170.0 35.9 19.1 3.3 608.0 14.1 416.0 149.0 24.5 <2.0 <3.5 537.0 1.4 11.4 < 2.3 16.1 227.0 46.0 143.0 177.0 24.0 67.2 7.2 1.6 2.6 42.7 0.9 37.4 7.3 1.3 <0.4 3.5

GK-25

4.9 22.6 1,301.0 <3.3 7.8 298.0 49.3 177.0 104.0 17.9 2.8 3,805.0 16.7 254.0 88.5 27.6 <2.9 <4.1 558.0 1.2 12.2 3.7 11.1 258.0 55.0 164.0 185.0 45.0 81.0 9.0 2.3 2.7 51.2 1.0 42.7 9.5 1.3 1.0 4.6

GK-26 4.9 72.3 1,852.0 <3.5 10.1 312.0 81.1 181.0 41.9 22.7 2.4 1,566.0 29.6 1,153.0 139.0 28.0 <2.1 6.0 467.0 1.0 11.0 3.8 16.8 212.0 55.0 156.0 156.0 15.0 68.3 8.2 2.0 3.5 36.5 0.8 34.9 8.2 1.4 0.9 4.3

GK-27 2.3 15.8 375.6 <2.9 8.5 218.0 23.9 98.0 22.3 10.0 3.3 437.0 8.7 213.0 141.0 19.9 <2.7 4.8 420.0 1.3 11.3 < 3.3 10.1 162.0 34.0 139.0 175.0 32.0 66.7 6.2 1.4 2.3 37.6 0.6 27.5 6.2 1.1 <0.5 2.9

GK-28

Z

r~

> Z

v~

>

Z

k.E. FOSCOLOS ET AL.

120

i

I0000

3000 I000

"~.

500

If,

:::i::~ iiiii

3OO

i

~' I

I

100 30I0

Y///////////~

iI!

!L!i! I

RANGEOF VALUES COMMONLYFOUND

:i:ii:i:i:i:i:i:i:ii:i:i i:i RANGEOF VALUES OF THIS STUDY ~ - -

RAREVALUES ICERTAIN, UNCERTAIN)

Fig. 4. Concentration of trace elements encountered in Greek lignitic ashes vs. reported values in the literature (modified after Swaine, 1962a, b).

from northeastern Greece have lost substantial amounts of sulphur during low-temperature ashing, ranging from 0.93% to 5.90%. All samples contain a substantial amount of non-volatile sulphur in the low-temperature ashes,

4.5. Sulphur concentration Total sulphur concentrations in lignites are presented in Figs. 5 and 6, and in Table VI. These results show that samples 3, 5 and 16-21 10

_

6

0 1

3

5

. ........ T o t a l

7

9

11 ........... L T A

13

15 17

19 21

.......... 7 5 0

Fig. 5. Sulphur content in lignites:low-temperature, 750 ° and I000 ° C ashes.

23

25 ---

27 1000

MINERALMATTERAND TRACEELEMENTS IN GREEK LIGNITES 100

"~ 80-

\

N

o 60-

@

40.

121

"acid rain" and other environmental hazards. Samples 20 and 22 (Table VI) indicate such a fixation. Though carbonates and pyrite were absent from the mineral composition anhydrite was detected in the 1000°C ash (Table II). During ashing organic sulphur has reacted with the calcium which is in the lignites to produce anhydrite, CaS04.

~ 20-

1'1 1'3 ,'5 1'7 1'9 2', 2'3 15 2'7

4.6. Organic and inorganic affinities of elements

No. of sample

Fig. 6. Per cent volatile sulphur based on upon the remaining sulphur in the 1000 °C ashes.

ranging from 0.66% to 5.85% (Table VI, column 3). Determination of the sulphur content in the 750 ° and 1000°C ashes indicated that lignites from northeastern Greece, Nos. 3-5 and 17-19 lose most volatile sulphur below 750°C while lignites from north-central Greece lose most volatile sulphur between 750 ° and 1000 ° C. High sulphur content in sample 21 is attributed to organic matter and pyrite, while in samples 19, 20 and 22 this is due to the high concentration of sulphur in organic matter. According to Korolev (1958) coal ashes with U concentration of > 104 ppm contain unusually high sulphur concentration. Sample 21 meets this condition. In general all samples, except most from north-central Greece, Nos. 6, 7, 9, 10 and 13, upon heating lost over 60% of their total sulphur (Fig. 6). Table VI indicates which sulphur-containing minerals disappear upon heating. Thus pyrite, meta-aluminite, jarosite, hexahydrite, epsomite and iron ammonium sulphate are totally decomposed while bassanite and gypsum are converted to anhydrite by loss of water. This variation in volatized sulphur might have quite important implications in combustion. If a large percentage of sulphur is fixed in the ash then presumably it is less of a problem than if emitted in the atmosphere, contributing thus to

The affinity of elements to organic or inorganic coal fraction have been studied following the indirect method used by Nicholls (1968), Gluskoter et al. (1977), Dilles and Hill (1984), Karner et al. (1986), Lindahl and Finkelman (1986), and Goodarzi (1987a, b). The concentration of the organically bound elements in coal decreases with increasing ash content. C1, Br and Ge are identified in this group, in agreement with results of Goodarzi (1987) and Goodarzi and Cameron (1987). Gluskoter et al. (1977) have found that B and Ge were concentrated in the light fraction of washed coals (low ash fraction). The concentration of inorganically bound elements increases with increasing ash content. Cr, Fe and Zn are qualified in this group. Gluskoter et al. (1977) found that these elements had inorganic affinities and that they were more concentrated in the heavier fraction of washed coals (high ash fraction). The organically bound elements in the present suite of lignites comprise As, Mo, Pb and U which show a decrease in their concentration with increasing ash content (Fig. 7 ). The same trend is followed by C1 and Mn. The inorganically bound elements comprise Ga, Hf and V. The concentration of these elements increases or remains constant with increasing ash content in lignites (Fig. 8). The same trend is obtained with Ba, Co, Cu, Rb, Sc, Sr, Ta and Th. Since the present ash of the lignite samples varied substantially, a dendograph (Fig. 9), grouping the elements in the lignitic ashes has

1.98 0.72 4.05

3.71

4.47

1.06

1.73 0.97

1.93

0.94

1.68

GK-4

GK-5

GK-6

GK-7 GK-8

GK-9

GK-IO

GK-11

(1)

Total sulphur

GK-1 GK-2 GK-3

Sample No.

6.69

4.2

6.6

3.90 1.48

6.16

16.70

10.10

7.01 0.80 17.81

(2)

1.56

0.85

1.82

1.51 0.75

1.06

3.16

3.53

1.92 0.69 2.74

4.38

5.93

9.10

6.07 10.44

8.57

10.78

2.39

7.31 0.59 3.02

0.76

0.97

1.82

1.51 0.47

1.02

1.57

0.69

1.52 0.44 0.25

(5)**

lignite

lignite (4)

on

(3)*

lated

lated on

back calcu-

1.14

5.20

7.60

5.70 9.30

5.70

7.60

0.14

4.21 0.12 1.25

(6)

1000 ° C ash

0.20

0.68

1.16

1.05 0.27

0.61

0.74

0.03

0.87 0.09 0.08

(7)***

lignite

on

lated

back calcu-

(8) +

0.12

0.09

0.11

0.22 0.22

0.00

1.31

0.18

0.06 0.03 1.31

0.80

0.00

0.00

0.00 0.28

0.04

1.59

2.84

0.40 0.25 2.49

(9) ++

750 °C

0.56

0.17

0.66

0.46 0.20

0.41

0.83

0.66

0.65 0.35 0.17

(•0) +++

1000 ° C

LTA

750° C ash

LTA

back calcu-

Volatilized sulphur at •

Sulphur in

1.48

0.26

0.77

0.68 0.70

0.45

3.73

3.68

1.11 0.63 3.97

(11)

total

88.1

27.7

39.9

39.3 72.1

42.4

83.4

99.2

56.1 87.5 98.0

Per cent of total sulphur volatilized

bassanite, pyrite bassanite anhydrite, pyrite, ammonium iron sulphate pyrite, gypsum, bassanite anhydrite, pyrite, epsomite baasanite, hexahydrite, pyrite bassanite baasanite, metaaluminite, pyrite bassanite, anhydrite, meta-aluminite, pyrite bassanite, anhydrite, pyrite meta-aluminite, bassanite, anhydrite, pyrite

Sulphide and sulphate minerals in LTA

Distribution of sulphur in residues and volatiles of different ashing temperatures - Sulphide and sulphate minerals in low-temperature and 1000 ° C ashes

TABLE VI

anhydrite

anhydrite

anhydrite

anhydrite anhydrite

anhydrite

anhydrite

anhydrite

anhydrite anhydrite anhydrite

Sulphate minerals in 1000° C ash

.~

.>

bO

2.60 2.71 6.31 5.55

6.38

4.29

1.82

2.92 6.29 3.94 9.45 0.73 3.19 2.60

1.58 0.88

2.13 2.95

GK-15

GK-16

GK-17

GK-18 GK-19 GK-20 GK-21 GK-22 GK-23 GK-24

GK-25 GK-26

GK-27 GK-28 2.13 2.92

1.32 0.88

1.89 0.39 1.09 4.22 0.66 3.04 2.56

0.89

2.62

5.85

0.95 4.70

1.93

5.13 4.71

3.37 2.45

9.71 2.17 9.31 0.06 1.50 4.27 2.75

17.03

6.21

12.78

5.20 9.24

6.24

1.49 2.06

1.22 0.66

0.88 0.04 0.14 0.02 0.65 2.07 1.55

0.39

0.98

3.55

0.95 2.71

1.07

2.42 3.10

1.13 1.06

5.40 0.03 0.04 0.01 0.33 1.11 0.32

13.10

3.50

9.70

4.50 6.70

3.30

LTA - low-temperature ash. * (3) = p e r cent S in LTA/100/LTA. ** (5) = p e r cent S in 750°C ash/100/750 °C ash (Table I) *** (7) = p e r cent S in 1000°C ash/100/1000°C ash (Table I). + ( 8 ) = ( 1 ) - (3). + + (9) = (3) - (5). +++(11)=(5)-(7).

16.62 12.79 2.29 12.20 1.33 5.11 3.91

20.40

13.07

14.90

3.34 12.10

0.99 5.21

GK-13 GK-14

8.91

2.30

GK-12

0.60 1.18

0.36 0.26

0.12 0.45 0.16

0.02

0.34

0.39

0.49

2.35

0.87 1.80

0.52

0.00 0.03

0.26 0.00

1.04 5.90 2.85 5.23 0.07 0.15 0.04

0.93

1.67

0.53

0.04 0.51

0.37

0.64 0.86

0.12 0.22

1.01 0.35 0.95 4.20 0.01 0.97 1.01

0.50

1.64

2.30

0.00 1.99

0.86

0.89 0.88

0.84 0.40

0.53 0.04 0.12 0.02 0.53 1.62 1.39

0.00

0.49

1.20

0.08 0.91

0.55

1.53 1.77

1.22 0.62

2.58 6.29 3.92 9.45 0.61 2.74 2.44

1.43

3.80

4.O3

0.12 3.41

1.78

71.8 60.0

77.2 70.4

88.4 100.0 99.5 100.0 83.6 85.9 93.8

78.6

88.6

63.2

12.1 65.4

77.4

bassanite pyrite, trace of bassanite trace of bassanite bassanite

bassanite bassanite, anhydrite, pyrite

pyrite

hexahydrite, metaaluminite, bassanite, pyrite bassanite bassanite, pyrite, hexahydrite, barite bassanite, pyrite, meta-aluminite, hexahydrite, jaxosite pyrite, bassanite, anhydrite, metaaluminite, jarosite anhydrite, gypsum, ammonium iron sulphate pyrite, bassanite trace of pyrite

anhydrite anhydrite

anhydrite anhydrite

anhydrite anhydrite anhydrite

anhydrite

anhydrite

anhydrite

anhydrite

anhydrite

anhydrite anhydrite

anhydrite

¢o

z

gx'J

7.

z

c~

7-

124

A.E. FOSCOLOSET AL.

been used for general information. Ni and Cr have high similarity index pointing to a common source, as discussed earlier. Ca and S03

are also together due to the presence of anhydrite (Table V). REE's have a high similarity index with Hf and Sc, indicating that lanthanides are teamed with the remaining trivalent elements of group IIIA*. The heavy REE's (HREE's: Dy, Yb, Lu, Ho) show a high similarity index (Eskenazy, 1987) while the light

*Eu upon reduction becomes divalent while Ce upon oxidation becomes tetravalent (De B a a r et al., 1988). 2000

600 400 •

•

[]

•

2OO E ¢z !

100

o~
60

o

mmm

• Om

[]

•

• o

[] []

40

•

[] n

•

Bo II D [] D

20 El

mlil

•

•

o

o [] D

10 []

[] o

S o

•

[]

I 10

[] []

o

l 20

I

I

I

I

I

30

40

50

60

70

80

% Ash 1000 600 400

200

lOO

E t.-, ¢3. l o

60 40

20

•

•

10

•

•

6 4

2 0

I lO

I 20

I 30

I 4O % Ash

I 50

I 60

I 70

80

MINERAL MATTER AND TRACE ELEMENTS IN GREEK LIGNITES

125

1000 600 400

200

_m

E Q. I ~3 D.

•

•

100 m

"mmm

60

•

•

40

•

• •

umm •

• •

20 10

•

I

I

l

I

!

I

!

10

20

30

40

50

60

70

80

% Ash 20000

10000 6000 4000 2000

1000 60O

m m

4OO E

e~ e~

20O

i

100

mm mm •

6O

• •

•

4O •

20

•

•

[]

[] •

[]

•

• []

10

[] Q []

.~ m

• []

• []

• mm

[]

Ill 121

6 []

4

[]

[]

121

[]

2 []

1 0

[]

mll 10

! 20

i 30

i 40 %

= 50

i 60

I 70

60

Ash

Fig. 7. Concentration of organically bound elements in lignites ( [] ) and lignitic ashes (m) vs. per cent ash in coals: (a) As; (b) Mo; (c) Pb; and (d) U.

126

A.E. FOSCOIA)S ET AL.

REE's (LREE's) show substantial dissimilarities. The latter can be attributed to leaching (Wedepohl, 1978; Goodarzi and Van Der FlierKeller, 1989 ). The only REE that shows a substantial trend is Ho. The average Ho concentration in ash in northeastern Greece (samples 16-18) is 50.7 ppm; in north-central Greece (samples 6-13) is 6.9 ppm and southern Greece, sample 23-28, is 2.4 ppm. Ce also shows an average concentration in ash of 113.6 ppm in central Greece (samples 6-13), while it decreases to 77 ppm in southern Greece (samples 23-28). The remaining REE's did not show any clearcut trend in respect to location, or any affinity towards organic or inorganic components of the

lignites, except La. The concentration of the latter increases as the per cent ash increases.

5. Conclusions

(1) Silicates and calcium sulphate minerals are present in all lignite samples. In addition, hexahydrite, meta-aluminite, jarosite and barite are concomitant with carbonates. Both groups of minerals are restricted to lignites from north-central Greece. (2) U is enriched, in respect to Clarke's value, from 2 to 1000 times in fourteen samples from northern Greece. The same samples are also

1000 600 400

E I

2OO

100 60 40

•

•

•

II

nan

2O •

•

10 6 4 I

E I

• In

2

• •

• •

1 0.6 0.4

0.2 0.1

i

I

I

I

I

I

I

10

20

30

40

50

60

70

% Ash

80

MINERALMATTERANDTRACEELEMENTSIN GREEKLIGNITES

127

2000

1000

,

6OO

,,

40O

"f

200 O

E

•

100

•

O

• o

60

D

[]

0 0 0

0 O

o

D []

[]

[]

(3

[]

I

O

i

40

20

D

10

n

0

D

0

n

6 4 2 1 0

I

I

I

I

I

I

I

10

20

30

40

50

60

70

80

% Ash

Fig. 8. Concentration of inorganically bound elements in lignites ([]) and lignitic ashes ( I ) vs. per cent ash in coals: (a) Ga; (b) Hf; and (c) V. TRACE ELEMENTS AND MAJOR OXIDES IN 1000 ° ASH

I

.2

I

.3 .4 .5 o= .c

.6 .7

.8 .9 1.0

[E[-

1 I

I

I

I

TRACE ELEMENTS AND OXIDES

Fig. 9. Similarity index between elements in lignitic ashes.

128

e n r i c h e d in As, Ba, Co, Cu, Hf, Ir, Pb, Rb, Sb, Sc, Sa, Ta, Z, Zr, T h , Y a n d R E E ' s . (3) Ashes f r o m all samples have > 100 p p m of Ba, Cr, Cu, Zn, Mn, Ni a n d Zr c o n c e n t r a tions. T h e s e values are w i t h i n the ranges rep o r t e d in the literature. H o w e v e r , Ni a n d Cr are enriched, relative to the r e p o r t e d ranges, in two samples, p r e s u m a b l y due to the p r o x i m i t y of p e r i d o t i t e s a n d s e r p e n t i n i t e s to the lignitic basin. (4) Ti, Sr, V, Mo, Co, L a a n d Y are also enc o u n t e r e d in relatively u n i f o r m c o n c e n t r a tions. H o w e v e r , M o is e n r i c h e d in the ashes of u r a n i f e r o u s lignites f r o m t h e Serres area, n o r t h e r n Greece. (5) H i g h c o n c e n t r a t i o n of As is e n c o u n t e r e d in t h e ashes of samples collected f r o m n o r t h e a s t e r n Greece. (6) T h e type and c o n c e n t r a t i o n s of major and t r a c e e l e m e n t s in lignites can be used to fingerp r i n t lignitic b a s i n s in G r e e c e because t h e y are r e s t r i c t e d in size a n d t h e e n r i c h m e n t in each t r a c e e l e m e n t is r e l a t e d to t h e type of t h e surr o u n d i n g rocks. An i m p o r t a n t b y - p r o d u c t of this line of r e s e a r c h is t h e obvious c o n n e c t i o n with p o l l u t i o n studies, because m a n y e l e m e n t s such as As, S, U, F have an e n v i r o n m e n t a l impact.

Acknowledgments T h e a u t h o r s wish to express t h e i r appreciat i o n to Drs. A.R. C a m e r o n a n d D. M o r r o w for t h e i r c o n s t r u c t i v e criticism a n d wish to t h a n k Mrs. J. Wong, Messrs. A.G. H e i n r i c h , R.A. D a v i d s o n a n d B.C. G o r h a m for t h e i r t e c h n i c a l assistance, f r o m t h e I n s t i t u t e of S e d i m e n t a r y a n d P e t r o l e u m Geology, Geological S u r v e y of Canada.

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