Grain size distribution and crystal growth in alumina hydrate precipitation process

In alumina hydrate precipitation process, caustic concentration and supersaturation of input aluminate liquor, temperature, seed charge and precipitation retention period are among the key parameters that determine the yield and quality of precipitated hydrate. Out of many properties, the grain size is the most important characteristic that determines its acceptability and value in the market. In this present investigation, studies have been made on effect of these variables with respect to particle size distribution of the precipitate product. Batch precipitation experiments were carried out on laboratory scale using aluminate liquor and seed hydrate from operating plant. Rate of crystal growth, population of fine particles, surface area and yield of the product after precipitation has also been examined.