GENESA BENTONIT DI KECAMATAN WONOSEGORO KABUPATEN BOYOLALI PROPINSI JAWA TENGAH DAN REKAYASA PEMANFAATANNYA SEBAGAI BAHAN BAKU PRODUK KERAMIK (The Genetic of Bentonite at Wonosegoro Vicinity Boyolali Residency Province o
| Main Author: | Perpustakaan UGM, i-lib |
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| Format: | Article NonPeerReviewed |
| Terbitan: |
[Yogyakarta] : Universitas Gadjah Mada
, 2005
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| Subjects: | |
| Online Access: |
https://repository.ugm.ac.id/23808/ http://i-lib.ugm.ac.id/jurnal/download.php?dataId=6769 |
Daftar Isi:
- ABSTRACT The research area is situated 40 kilometers north of Boyolali at Kendeng antiklinorium folding mountain. Physiographically, it lies on a thrust-fold belt, Western Kendeng Zone, Northernpart of East Java Basin. Litologic varian composing the research area consists of silisiclastic rocks, such as sandstone, siltstone, claystone, and layer of bentonite. Sedimentary character and stacking pattern showed that the sedimen was deposited by turbidit current mechanism. Wrench fault and anticline are the major structures. Shear joints and drags are occasionally found on silisiclastic sedimentary rocks layer. Antiklinorium axis is EastNortheast-WestSouthwest according to the layer position itself where is vertical. Wrench fault is Northwesat-Southeast. Bentonite was originated from material that composed of pyroclastic fall deposit which was altered. The main process was devitrivication of volcanic glasses. The other process was the solution of primary minerals and lithic fragments. The volcanic glasses consisted mostly of vitric tuff are unstable, and easy to alter in alkaline environment forming liquid which contains Si+4 cation. Meanwhile, solution of primary minerals and Ethic fragments formed liquid containing cations of Ti+4, A1+3, Ca+2, Na+, K+, Fe+3, and Mg+2. All of the liquid made from those processes were mixed to form a silicate liquid. When it crystalized, this liquid formed secondary minerals such as montmorilonite. Dip of layer of bentonit is vertical and EastNortheast-WestSouthwest oriented the same as the layer of the surounding area. The properties of ceramic products consisting of 44-45% Mayong feldspar, 44-45% kaolin, and 10-12% bentonite, were as follows : idealized dry shrinkage 4.68-5.25% (idealized burn shrinkage 5.50-5.62%), porosity of idealized dry and burn shrinkage 35.042-39.473%, the modulus of rupture 237.712-401.887 N/cm2, and water plasticity 41.19-44.81%. The increase of bentonite content improved the properties of the products. Keywords: bentonite, vitric tuff, devitrivication, ceramic.