Gravity flow of some steelmaking raw materials with particular reference to the effects of vibration

The thesis comprises two main parts : ( i) A compilation of flow properties of the most difficult bulk solid materials handled by the Raw Materials area of Australian Iron & Steel, and a check on the various bin designs used in this area of the plant to predict flow behaviour with these materials. (ii) A study of the effect of vibration on the strength of bulk solid materials and on the frictional forces between a surface and a material such as exists in vibrating baffles or vibrating panels. The first part of the work was done using the experimental methods of Jenike, a pioneer in this field. The vibration section involved the construction of a suitable vibrating machine and shaking samples of ore in the Jenike shear cell either before shearing or during shearing. To get more accurate results when shearing was taking place during vibration, a special tilting device was used in preference to the Jenike machine It may be concluded from the first part of the work that many bins are not designed properly for the material they are expected to handle, and only the use of mechanical flow promoting devices and frequent cleaning particularly in wet weather keep the materials flowing. The vibration work showed two contrasting points: (a) that a confined sample of material gains considerable strength due to over-consolidation during vibration, and (b) the same confined sample has a considerably lower wall friction when the wall is being vibrated.