2nd IASME / WSEAS International Conference on GEOLOGY and SEISMOLOGY (GES '08), Cambridge, UK, February 23-25, 2008

Geology, Characterization, Quality improvement and Recommended Utilization of Natural Zeolite (Zeolitic Tuff) Deposits from Gunung Kidul, Special Teritory,

ARIFUDIN IDRUS1*, ANASTASIA DEWI TITISARI2, RAHMAN SUDIYO3 AND R. SOEKRISNO4

1, 2Department of Geological Engineering, 3Department of Chemical Engineering, and 4Department of Mechanical Engineering, Faculty of Engineering, Gadjah Mada University, Yogyakarta, INDONESIA

Abstract: - The natural zeolite (zeolitic tuff) in Gunung Kidul -Yogyakarta, Indonesia is the most promising deposit to be ranked as the most prominent commodity. Lithologically, the areas are occupied by interbedding green stone breccia, zeolitic tuff and sandstone tuff layers. Zeolitic tuff is characterised by green in colour, coarse – fine sand grain sized, with a variably thickness of up to 15 m. Zeolite minerals consist of clinoptilolite and mordenite with a range of 3.52-7.17 and 6.29-18.47 wt. %, respectively. Mordenite (Na-rich zeolite) is more abundant than clinoptilolite (K-rich zeolite). This agrees well with the bulk-geochemical composition of the rocks, where Na2O content (1.06-1.51 wt. %) is relatively higher than K2O (0.71-0.98 wt. %). Initial (un-activated) CEC of the zeolitic tuffs vary from 39.41 to 67.84 mg Na2O/100 gr zeolite. The measured resources of zeolitif tuffs in the studied areas are 451,248 tonnes. If the average percentage of zeolite minerals (clinoptilolite and mordenite) is 18.14 wt. %, the total amount of zeolite minerals within the rocks are 81,856 tonnes. The quality of zeolites (in term of CEC) was improved by thermal activation. The optimum operating condition was achieved at temperatures of 250 OC during 1 hour heating, which is indicated by an increase of CEC from 67.37 to 88.26 mg Na2O/100 gr zeolite. The Gunung Kidul natural zeolites are recommended to be an additive material for a slow release fertilizer.

Key-Words: - Deposit geology, natural zeolite, characterization, quality improvement, slow release fertilizer.

1 Introduction among the highest rank compared to other Industrial minerals are abundant in the deposits have been developed in Indonesia (in , Yogyakarta, Indonesia, term of cation exchange capacity). Therefore, in and are potentially can be a major income for the this project, we proposed four areas to be region. Among these industrial minerals, the investigated including Serut, Sidomulyo, natural zeolite is the most promising deposit to be Hargomulyo and Jatirejo, which are situated in ranked as the most prominent commodity. The Gunung Kidul regency, Yogyakarta (Fig. 1). development of zeolite resources will support the development of the local zeolite-based industry. In 3 Regional Geology turn, this will stimulate the development of the Regionally, the studied area is situated in economy growth of the local community. the northwestern part of the Southern Mountain. It This research deals with the deposit geology and characterization of the natural zeolite is comprised of Oligocene-Miocene volcano- deposit (in term of mineralogy, geochemistry and clastic sediments, which have the dips of layers physical properties), quality and quantity relatively to south [5]. The regional stratigraphy of (resources), conducting research on applications of the Southern Mountain (from the oldest to the zeolites for additive fertilizer materials for the youngest) consists of the Kebobutak Formation, small local enterprises as a pilot project for Semilir Formation, Nglanggran Formation, designated application. Sambipitu Formation, Formation, Kepek Formation and Quartenary alluvium. 2 Research Area The zeolitic tuff, in the research area, is a Preliminary studies e.g. [1], [2], [3] and member of the Kebobutak Formation. The [4] revealed that the quality of natural zeolites Kebobutak formation is covered conformably by from Gunung Kidul regency, Yogyakarta, is the Semilir Formation, which is characterised by

ISSN: 1790-2769 Page 21 ISBN: 978-960-6766-39-8 2nd IASME / WSEAS International Conference on GEOLOGY and SEISMOLOGY (GES '08), Cambridge, UK, February 23-25, 2008 dacitic breccia, dacitic pumice tuffaceous and 5 Results and Discussion white tuff [6]. The Kebobutak Formation is 5.1 Deposit geology composed of interbedding sandstone, vitriceous In general, the studied areas, including tuff and zeolitic green stone layers, which is Late Serut, Sidomulyo, Hargomulyo and Jatirejo are Oligocene – Lower Miocene in age [7]. occupied by interbedding green stone breccia, zeolitic tuff and sandstone tuff layers. The greenstone breccia is comprised of angular fragments derived from zeolitic tuffs, which are mecascopically green in colour, granular-sand grain sized with matrix of tuff. Zeolitic tuff is Research Area Jakarta Prov ince Boundary KLATEN characterised by green in colour, coarse – fine

” Yogyakarta

0

0 sand grain sized, with a thickness of 0.1–3.00 m.

’ HINDIAN OCEAN

0

0

7 Sandstone tuff is typified by light grey in colour 0 and coarse – fine sand grain sized. Serut prospect CENTRAL PURWOREJO JAVA KLATEN situated in the north-western part of the studied SLEMAN

”

0 area has two layers of zeolitic tuffs (TZ-1 and TZ-

0

’

0

3 2) with a thickness of 1.3 and 15 m, respectively. YOGYAKARTA

7 0 Four layers of zeolitic tuffs are recognised in

WATES GUNUNG KIDUL Sidomulyo (Fig. 2).

” BANTUL B D

0 WONOSARI GEOLOGICAL MAP OF ZEOLITE DEPOSIT

0 25 ’ Sidomulyo prospect, Gunung Kidul regency, 0 Yogyakarta province

0

8 N 0 YOGYAKARTA

0

HINDIAN OCEAN 5 6 0 10 SPECIAL 5 20

3

1 9 0 50 m N TERITORY Scale 1:500 Contour interval 2 meter 0 30 60 km W E F Keterangan 0 4cm Contour line

0

S 0

6

5

3 Strike and dip

1 110 11’15” 110 22’30” 110 33’45” 110 45’00” 9 20 Fault approximately 20 TZ-4 Zeolitic tuff - 4 unit 0

5 BP-4 Sandstone - 4 unit

5

5

3

1 Fig. 1 Location map of research area, which is 9 TZ-2 Zeolitic tuff -3 unit 21 Sidomulyo Bx-3 Greenstone breccia - 3 unit 25 situated in Gunung Kidul regency, Yogyakarta 3 0 9 BP-3 Sandstone - 3 unit 3 0 0 3 6 3 4 0 7 8 0 0

0

0 H TZ-2 Zeolitic tuff -2 unit

5

5

Special Teritory, Indonesia. 3

1 9 BP-2 Sandstone - 2 unit Bx-2 Greenstone breccia - 2 unit BP-1 Sandstone - 1 unit

25 TZ-1 Zeolitic tuff - 1 unit

0

5

4 4 Analytical Methods 5 3 Bx-1 Greenstone breccia - 1 unit

1

9

3

7 0 B Geological S ection A total of 20 natural zeolites (zeolitic tuff) 25 A 18 Borehole location

0

0 samples taken from Gunung Kidul regency, 4

5

3

1

9 18 18 Yogyakarta, were analysed in term of mineralogy, A 0452000 0452050 C 0452100 EG0452150 0452200 0452250 GEOLOGICAL SECTION geochemistry and physical properties. For H : V = 1:1 A B mineralogical characterization, petrographical, 395 395 385 385 TZ-4

375 -2 375 P-2 Bx 1 1 P-4 -2 B P- x- XRD (X-ray Diffraction) and SEM (Scanning B 3 TZ B B - 365 TZ x-3 365 B 3 - BP Electron Microscope) analyses were performed. 355 355 C D 395 395 1 Geochemical characterization was conducted by 385 -2 1 TZ- -2 - 385 BP-4 TZ-3 TZ -2 Bx BP -1 BP Bx 375 -3 3 BP 375 Bx- analysing 20 zeolitic tuff samples by means of 365 365 Sidomulyo XRF (X-ray Fluorescence) for major oxides and E F 400 400 390 390 1 -2 BP- -1 minor elements. Physical properties, including BP TZ 380 -3 - 3 -2 380 Bx BP -2 Bx TZ 370 370 water absorption, specific gravity, pH, and Cation G H 400 BP-3 400 Exchange Capacity (CEC) were also analysed. 390 390 2 TZ- -2 380 BP 380 The geology of deposit was mapped out 370 370 on a detailed scale (1:500). Core drilling was conducted for 4 points with a total depth of 24 meters. Based on the geological maps and drilling Fig. 2 Geological map and cross-sections of data, the measured resources (quantity) of the natural zeolites (zeolitic tuffs) of Sidomulyo natural zeolites could be estimated by applying a prospect, Gunung Kidul, Yogyakarta, Indonesia. section method. To improve the quality (in term of CEC) of the natural zeolites, a thermal activation The zeolitic tuffs are megascopically process was also performed. characterised by light green – pale green in color, clastic texture and silt – fine sand in grain size with a thickness ranging from 1.5 to 4 m

ISSN: 1790-2769 Page 22 ISBN: 978-960-6766-39-8 2nd IASME / WSEAS International Conference on GEOLOGY and SEISMOLOGY (GES '08), Cambridge, UK, February 23-25, 2008

(thickness is calculated on the basis of geological structure of montmorilonite and volcanic glass reconstruction and core drilling). Some layers (precursor of zeolite minerals) are also identified. show a normal gradational structure from fine sand to silt size. Hargomulyo located in the south- eastern part of Sidomulyo prospect has four layers of zeolitic tuffs with a thickness ranging from 1.6 to 3.8 m (Fig. 3). Jatirejo situated in south-eastern part of research are consists of two zeolitic tuff layers, with a thickness of 10 and 12 m. Detailed mapping exhibits that structural geology developed in the studied area is uncomplex and only manifested by the presence of normal fault in

Serut. The research area is interpreted as a flank of fold, which is indicated by the general trend of layer dips towards south-east and south-west.

Fig. 4 Representative XRD analysis of zeolitic tuff from Gunung Kidul regency, Yogyakarta, showing the presence of mineral phases, including zeolite minerals, clinoptilolite (Cpt) and mordenite (Mor).

A Mor

Mor

Fig. 3 Zeolitic tuff layer with a thickness of 3.8 m at Hargomulyo, Gunung Kidul, Yogyakarta. Mor

5.2 Characteristics of natural zeolites The petrograpical analysis indicates that the rock is typified by a clastic texture, composed of volcanic glass (44.3-61.3 vol.%), quartz (4.1- 11.0 vol.%), plagioclase (2.0-12.0 vol.%), B orthoclase (0.2-3.4 vol.%), chlorite (1.3-5.7 Mor vol.%), magnetite (1.9-3.7 vol.%), serisite (1.0-1.5 vol.%) and altered minerals from volcanic glass, Cpt which is interpreted as zeolite minerals (15.7-27.1 vol.%). The X-ray Diffraction (XRD) analysis of the zeolite samples show the peaks of diffraction are belong to clinoptilolite and mordenite (zeolite minerals), also the other minerals including montmorilonite, plagioclase and quartz (Fig. 4). The samples are predominantly composed of mordenite, compared to clinoptilolite. The presences of mordenite and clinoptilolite are also well recognised by scanning electron micrograph (SEM analysis), illustrated by Fig. 5A and B, Fig. 5 Scanning electron micrograph of (A) respectively. Mordenite is mostly characterised by mordenite needles/fibers [Mor], and (B) needles/fibers structures (Fig. 5A), whereas clinoptilolite [Cpt] with a monoclinic symmetry of clinoptilolite occurred in monoclinic symmetry of blades and laths in zeolitic tuff from Gunung blades/tabular and laths (Fig. 5B). Webby Kidul regency, Yogyakarta, Indonesia

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Bulk-geochemistry of Gunung Kidul hour of activation), one can conclude that the zeolitic tuffs are characterised by major oxides activation process can increase the cation SiO2 (72 wt. %), Al2O3 (9-11 wt. %), FeO (1.6 wt. exchange capacity of the zeolite. As seen on the %), MgO (0.8-1.2 wt. %), CaO (3.3 – 4.5 wt. %), graph, both temperature and duration of heating of the activation process affect the cation exchange Na2O (1.1-1.5 wt. %), K2O (0.7-1 wt. %) and H2O (8 wt. %). The normative calculation indicates the capacity. High temperature and long heating presence of ilmenit (0.46-0.68 wt. %), magnetite period gives high CEC value. However, the (1.72-3.66 wt. %), K-feldspar (1.66-2.95 wt. %), temperature can not be set too high as it could change the zeolite structure resulting in lower chlorite (0.99-2.41 wt. %), albite (0.25-2.65 wt. CEC value (see CEC value at 250 oC and 300 oC). %), anortite (0.91 – 2.95 wt. %), montmorilonite Data on the graph suggests the optimum condition (0.72 – 7.16 wt. %), illite (2.66 – 4.21 wt. %) and for activation process is at the heating temperature quartz (6.45 – 16.86 wt.%). Zeolite minerals of 250 oC and duration of 1 hour. consisting of clinoptilolite and mordenite are also detected in a moderate amount with a range of )

e o

t 92 88.26 200 C 3.52-7.17 and 6.29-18.47 wt. %, respectively. i

l o Volcanic glass was interprerted as a predominant o 88 250 C

e phase with amount of 45.52-54.79 wt. %. z 81.20 84 o

r 80.16 300 C

Mordenite (Na-rich zeolite) is more abundant than g

80

0 clinoptilolite (K-rich zeolite). This agrees well C

0 E 76 73.61

1 with the bulk-geochemical composition of the C / 72 70.23 rocks, where Na2O content is relatively higher O 67.37 67.35

2 than K2O. 68 69.44 68.92 a

The physical properties of zeolitic tuffs N 64

. 63.63 are represented by Cation Exchange Capacity g 60

m (CEC), acidity (pH), water absorption and density . ( 0 1 2 3 Initial (un-activated) CEC of Gunung Kidul Duration of activation (hours) natural zeolitic tuffs vary from 39.41 to 67.84 mg Fig. 6 Relationship between duration of thermal Na O/100 gr zeolite. The acidities (pH values) of 2 activation (hours) and CEC of representative zeolitic tuffs are slight alkali with pH ranging zeolitic tuff from, Gunung Kidul Regency, from 7.3 to 8.3. Water absorption analysis Yogyakarta, Indonesia. Notes: CEC at zero hour revealed a wide range of values, varying from of activation is unactivated CEC of the sample. 13.42 to 27.60%. Density of the zeolitic tuffs are 3 relatively low (1.34 – 1.74 gr/cm ). Density data is 5.4 Utilization useful for estimation of measured resources Zeolite is a very useful industrial mineral (quantity) of the natural zeolite deposits in the that can be utilized by different types of industries studied areas. such as agriculture, animal husbandry, water Zeolite deposits in the four studied areas treatment and additive fertilizer materials. Based were mapped out on a detailed scale (1:500). By on the mineralogical, geochemical and physical using this scale of deposit maps, the measured characteristics, optimum duration and temperature resources of the deposits enable to be estimated by conditions of activation as well as CEC (Cation applying a section method and verified by core Exchange Capacity), the natural zeolites (zeolitic drilling data. The estimation of zeolitic tuff in the tuffs) in the studied areas are recommended to be areas indicates the total of measured resources of used for additive materials for fertilizer. 451,248 tonnes. If the average prosentage of Unfortunately, there is no quality standard found zeolite minerals (clinoptilolite and mordenite) is in literatures for zeolitic tuffs required in this 18.14 wt.%, the total amount of zeolite minerals application. However, previous experimental within the rocks are 81,856 tonnes. study conducted by Widiasmoro et al. (2000) revealed that the zeolitic tuffs from this region are

suitable to be used as an additive material for 5.3 Quality improvement zeolite-based environmentally fertilizer. The quality of zeolites (in term of Cation Additionally, the reason of choosing the Exchange Capacity, CEC) was improved by application of the natural zeolites for additive thermal activation. Measurement result on CEC of fertilizer materials, due to: (1) the surrounding the activated natural zeolite is presented in Fig. 6. areas where the natural zeolites occurred are Comparing the data presented on the graph (Fig. predominantly as agriculture and animal 6) with those belong to unactivated zeolite (at zero husbandry region, (2) the treatments of the natural

ISSN: 1790-2769 Page 24 ISBN: 978-960-6766-39-8 2nd IASME / WSEAS International Conference on GEOLOGY and SEISMOLOGY (GES '08), Cambridge, UK, February 23-25, 2008 zeolites to be additive fertilizer materials are Parikesit. The idea of research subject was initially relatively uncomplicated and easily-used for the prompted by Prof. Koichiro Watanabe and Dr. local small-medium enterprises in the region, and Lucas Donny Setiadji. Ir. Widiasmoro, M.T. and (3) the use of zeolite is an environmentally Dr. I Wayan Warmada are also acknowledged for fertilizer as it allows nutrients to be realeased to their valuable and discussion. the root in a slow plant root demand-driven fashion. References: [1] Widiasmoro, Djoko Wintolo, and Sumardi, P., 6 Conclusion Profile Investation of Sampang Zeolite at The natural zeolite (zeolitic tuff) in Gedangsari Area, Gunungkidul Regency, Gunung Kidul regency, Yogyakarta Special Yogyakarta, The Mining Official of Yogyakarta Teritory, Indonesia is the most promising deposit Special Territory Government - Geological to be ranked as the most prominent commodity. Engineering Department, Gadjah Mada Lithologically, the areas are occupied by University, Unpublished department report (in interbedding green stone breccia, zeolitic tuff and Indonesian), 2000, 109 p. sandstone tuff layers. Zeolitic tuff is characterised by green in colour, coarse – fine sand grain sized, [2] Titisari, A.D., Widiasmoro, Characteristics, with a variably thickness of up to 15 m. Study on Measured Resources and Quality of characterization indicates that zeolite minerals Bantengwareng Zeolitic Tuff at Gedangsari Area consist of clinoptilolite and mordenite in a of Gunungkidul Regency as agriculture products moderate amount ranging from 3.52 to 18.47 wt. absorbent and Fertilizer, Geological Engineering %. Mordenite (Na-rich zeolite) is more abundant Department, Gadjah Mada University, than clinoptilolite (K-rich zeolite). This agrees Unpublished SP-4 internal report (in Indonesian), with the geochemical composition of the rocks, 2004, 41 p. where Na content is relatively higher than K. Initial (unactivated) CEC of the zeolitic tuffs vary [3] Yuminti, S., Widiasmoro and Titisari, A.D., from 39.41 to 67.84 mg Na2O/100 gr zeolite with The Characteristic and Genesis of Zeolitic Tuff in slight alkali acidities (pH of 7.3-8.3). Water Bantengwareng Area, GunungKidul Regency – absorption shows a wide range of values (13.42- Yogyakarta, Proceeding of the 34th IAGI 27.60 %). Density of the zeolitic tuffs are (Indonesian Association of Geologists), 2005, pp. relatively low (1.34 – 1.74 gr/cm3). Based on the 37-47. detailed deposit maps (scale 1:500) and core drilling data, measured resources of zeolitif tuffs [4] Titisari, A.D., Idrus A., and Widiasmoro, in four studied areas are 451,248 tonnes. The Mineralogical Characteristics of The Sampang quality of zeolites (in term of CEC) was improved Zeolitic Tuff, Gunungkidul – Indonesia and Its by thermal activation. The optimum operating Utilization as Fertilizer, Proceeding of the 4th condition was achieved at temperatures of 250 OC International Workshop on Earth Science and during 1 hour heating, which is indicated by an Technology, Kyushu University, Japan, 2006, pp. increase of CEC from 67.37 to 88.26 mg 423-430. Na2O/100gr zeolite. Based on social-economic condition of the local community (as agriculture [5] van Bemmelen, R.W., The Geology of and animal husbandry region) as well as the Indonesia, Vol. 1A, Martinus Hijhoff, The Hague, mineralogical, geochemical, physical charac- The Netherlands, 1970, 732 p. teristics and an increase of CEC of the Gunung Kidul zeolitic tuffs, the best utilization of the [6] Marks, P., Stratigraphic Lexicon of Indonesia, deposit is to be an additive material for a slow Publikasi Keilmuan No.31, Seri Geologi, Pusat release enviromental-friendly fertilizer. Djawatan Geologi, Kementrian Perekonomian R.I. Bandung, 1957, 233 p. 7 Acknowledgments This paper presents a brief result of the [7] Soeria-Atmaja, R., Maury, R.C., Bellon, H., first year I-C-U (Industry-Community-University) Pringgoprawiro, H., Polve, M., Priadi, B., The collaborative research financed by JICA Hi-Link Tertiary Magmatic Belt in Java, Procceding of Project. The authors are very thankful to the Symposium in the Dynamic of Subduction and Its management of the JICA Hi-Link Project Products, Research and Development Center of particularly Prof. Ryuichi Itoi, Prof. Sudjarwadi, Geotecnology, Indonesia Institute of Science (LIPI), Bandung, 1991, pp. 98-121. Prof. Retno Sunarminigsih and Prof. Danang

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