ÇAMUR HALİNDEKİ SERAMİK HAMMADDELERİNİN KURUTMA KİNETİĞİNİN İNCELENMESİ

Seramik üretimi sırasında uygulanan en önemli metotlardan birisi hammadde ile suyun belli oranda karıştırıldıktan sonra yapılan konvektif kurutmadır. Bu çalışmada çamur halindeki seramik hammaddesi konvektif bir kurutucuda farklı ısı transfer mekanizmalarına göre incelendi. Deneysel çalışmada, ısı ve kütle transferinin etkilerini anlamak için i) alt yüzeyi yalıtımlı, tek yüzeyden ısı ve kütle transferine izin veren, ii) ısı transferini arttırmak için kalıbın alt yüzeyinin paslanmaz çelik saçtan yapıldığı iki yüzeyden ısı transferine izin veren, iii) her iki yüzeyden taşınımla ısı transferine izin veren olmak üzere üç farklı kalıp kullanıldı. Bütün deneyler, ham maddelerin kuruma zamanını belirlemek için üç kalıp için de iki farklı kalınlık değerlerinde yapıldı. Deneysel sonuçlar literatürden alınan birkaç ince katman kuruma modelleri ile karşılaştırıldı. Midilli vd. modeli en uygun kurutma modeli olarak belirlendi. Aynı zamanda, efektif su buharı difüzyon katsayıları Crank Modeli’ ne göre farklı ısı transfer mekanizmaları için hesaplandı (Crank, 1975).

EVALUATION OF DRYING KINETICS OF SLURRED CERAMIC RAW MATERIALS

One of the most popular applied methods during the production of ceramics is convective drying by mixing rawmaterials and a certain proportion of water to achieve homogeneity. In this study, drying characteristics of slurred rawmaterials have been evaluated according to different heat transfer mechanisms in a convective dryer. This experimental studywas performed by using three different molds to understand the effects of heat and mass transfers from i) only one surfacewhere the bottom surface was isolated, ii) two surfaces where one side of the mold was covered with an stainless steel plateto enhance heat transfer, iii) two surfaces. All experiments were conducted with two different thickness values for all threemolds to determine the drying time of raw materials. The experimental results were compared to some thin-layer dryingmodels from the literature. Midilli et. al. model was found the best relevant drying model. Also, effective moisture diffusioncoefficients were found for different heat transfer mechanisms according to Crank’s model (Crank, 1975).

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