The Optimal Ratio of Mixed Talc Silica and Narathiwat Clay for Cordierite-Mullite Refractories

In this paper, effects of incorporation of Narathiwat clay (NT), talc and silica on the mechanical properties of cordierite-mullite refractories were investigated. The starting raw materials were mixed in different ratios and fired at 1300 °C for 2 hours. XRD patterns of fired refectories indicated cordierite and mullite phases. The fired samples were studied the firing shrinkage, water absorption, bulk density, apparent porosity and bending strength of the cordierite-mullite refractories. The optimum condition was achieved for the composition of 20% Talc that had shrinkage: 11.78%, water absorption: 4.16%, bulk density: 2.28 g/cm3, apparent porosity: 9.2% and bending strength: 330.82 kg/cm2. The results thus showed that Narathiwat clay, talc and silica was a potential materials for use kiln furniture cordierite-mullite refractories.

THE MAIN ‘MIDDLE BYZANTINE PRODUCTION’ AND POTTERY MANUFACTURE IN THEBES AND CHALCIS

The article relates the results of archaeometric and archaeological investigations of the relationships between some well-known types of Byzantine table wares and pottery manufacture in Thebes and Chalcis, focusing on the period from the twelfth to the fourteenth centuries ad.We currently accept that several twelfth–thirteenth century types, such as ‘Green and Brown Painted Ware’, ‘Fine Sgraffito Ware’ and ‘Aegean Ware’, form part of a single, main, long-lasting production of Byzantine ceramics, called here main ‘Middle Byzantine Production’ (MBP), which was distributed and diffused in the whole Mediterranean area, and especially in its eastern part. The discovery of kiln furniture and pottery wasters in rescue excavations in Thebes and Chalcis gave the opportunity to define chemical reference groups for the two cities, and to test the hypothesis of a potential origin of the MBP in Central Greece. The results point to Chalcis, then the harbour of wealthy Thebes with a strategic location on maritime trade routes, as the place of manufacture of the MBP. Chalcis, which is now seen as a main pottery production site, is envisaged within its historic context. The persistence of the MBP after the Frankish conquest, without noticeable morphological changes, questions the impact of this conquest on both trade networks and dining habits.The political fragmentation of the thirteenth century gradually changed the conditions that facilitated the predominance of the MBP, and led to the establishment of a number of regional workshops whose ceramics were mainly destined to cover local markets. While continuing earlier techniques, they introduced new types, prominent among which was the ‘Sgraffito with Concentric Circles’ (previously related to ‘Zeuxippus Ware’). Thebes was one of these new workshops probably appearing from the mid-thirteenth century and continuing at least to the early fourteenth century. Chalcis eventually followed the same course, and its production may have carried on well into the Ottoman period.