effect of waste plaster of paris on physical and mechanical .13. 2.4. The bulk density of clay bodies with different sintering temperature. 14. 2.5. The mechanical properties of pottery body and clay. 16. 2.6. Properties of clay. 20. 2.7. Properties of ball clay. 21. 2.8. Properties of Kaolin. 23. 2.9. Composition of feldspar in ceramic product. 26. 2.10 The current studies on gypsum as a filler.effects of kaolin on properties of gypsum plaster,Effect of Plaster of Paris Waste and Sintering . - Science Direct12th Global Conference on Sustainable Manufacturing. Effect of Plaster of Paris Waste and Sintering Temperatures on Physical. Properties of Pottery . Gypsum is an ionic mineral with the crystal structure consists of pairs of adjacent layers parallel to the b- axis containing the Ca2+ cations and the tetrahedral SO4 anionic.