Non-traditional whiteware based on calcium aluminate cement

Abstract

The article introduces the differences in the properties of whiteware (porosity, strength, thermal expansion coefficient) when a non-traditional binder is used. Pure calcium aluminate cement and a mixture of kaolin and calcium aluminate cement compared with traditional plastic raw material for whiteware -kaolin -are used for the preparation of whiteware bodies with a constant content of non-plastic raw materials: K-Na feldspar and quartz sand. The results are discussed in connection with the microstructure of the fired body of prepared whitewares (mineralogical composition). Calcium aluminate cement (CAC) in whiteware raw-material mixtures is an interesting alternative to kaolin for a higher strength of the green and fired bodies. Using calcium aluminate cement reduces the sintering temperature of the fired body and significantly changes its mineralogical composition: anorthite is the main mineralogical phase instead of mullite, which is typical for standard porcelain bodies made from raw-material mixtures based on kaolin. The coefficient of thermal expansion increases with an increasing content of CAC in the raw-materials mixture. Keywords: calcium aluminate cement, kaolin, whitewarê lanek predstavlja razlike v lastnostih porcelana (poroznost, trdnost, koeficient toplotnega raztezka),~e se uporabi neobi~ajno vezivo.^isti kalcijev aluminatni cement in me{anica kaolina in kalcijevega aluminatnega cementa, v primerjavi s tradicionalno plasti~no sestavino porcelana -kaolina, so bili uporabljeni za kerami~na telesa s konstantno vsebnostjo neplasti~nih surovin; K-Na glinenec in kvar~ni pesek. Rezultati so razlo`eni v povezavi z mikrostrukturo telesa pripravljene keramike (mineralo{ka sestava) po`ganju. Kalcijev aluminatni cement (CAC), v me{anici surovin za keramiko, je zanimivo nadomestilo za kaolin, za vi{jo trdnost zelenega in`ganega telesa. Uporaba kalcijevega aluminatnega cementa zni`a temperaturo sintranja`ganega telesa in mo~no spremeni njegovo mineralo{ko sestavo; anortit je glavna mineralo{ka faza namesto mulita, ki je zna~ilen v standardnih porcelanskih telesih, izdelanih iz me{anice surovin na osnovi kaolina. Koeficient toplotnega raztezka se pove~uje z ve~anjem vsebnosti CAC v me{anici surovin. Klju~ne besede: kalcijev aluminatni cement, kaolin, porcelan