Research On Technological Properties Of Plaster Mould Mixture

In this paper, the linear expansivity of plaster mould mixture together with tensile strength, flowability and solidification time were studied mainly. With quartz flour and high-alumina bauxite as fillers, the relationship between various factors and technological properties were obtained by testing the effects of filler type, water percentage and filler percentage. This work could lay the theoretical foundation for the development and preparation of plaster mould mixture with different performance requirements in the future, and could make technical reserves of related studies for other enterprises.The main contents are:1,In order to improve the linear expansivity, orthogonal test method was adopted. And technological properties of the plaster mould mixture with different materials and various proportions were tested.2,Without reducing general specification of the plaster mould mixture, different contents of magnesium sulfate were added to gypsum and quartz powder-gypsum mixture. The proportion of soluble gypsum mixture with quartz flour as filler was optimized as the following : water addition amount is 35% of the weight of filler and gypsum, filler addition amount is 65% of the weight of filler and gypsum, and magnesium sulfate addition amount is 24% of the weight of magnesium sulfate and gypsum.3,Microwave drying technique was studied by the method of weighing to constant weight, and compared with electric oven and box-type resistance furnace. The results showed that microwave drying can bring a fast drying rate in the first stage together with shorter drying time, high production efficiency and better economic benefits. The relationship between power and drying time was also concluded that : with increasing power, the drying time of the sample became shorter, the water content became smaller, and drying efficiency became better.