STUDIES ON FLOW PROPERTIES OF GUM ARABIC POWDER

Abstract

In the manufacture of tablets, tableting processes, design of reliable solids handling equipment such as hoppers, silos, and storage bins the flowability of powders and other flow property data are most important characteristics. In the case of powder discharge from silos or hoppers, arches and ratholes may be formed, especially in the presence of humid air, resulting in poor flow of the powder. Keeping in this view flow properties of gum arabic powder was evaluated by powder flow tester in which gum arabic powder with particle size 700 micron to 300 micron was tested. It was found that gum arabic powder follow two type of flow behaviour first easy flowing between 0.6 to 3 kPa major principal consolidating stress, σ1 and 0.07 to 0.30 kPa unconfined faliure strength, σc then free flowing between 3 to 9 kPa major principal consolidating stress, σ1 and 0.30 to 0.80 kPa unconfined faliure strength, σc. The critical arching values for gum arabic were density 717.3 kg/m3, effective angle of internal friction 38oC, effective lengh 0.011m at stress level 0.038 kPa and critical rathole values were density 797 kg/m3, effective angle of internal friction 36.5oC, diameter 0.29 m at stress level 0.80 kPa. All these properties can be used in handling and processing equipments.