Title of Experiment conducted by me: Measurement of bulk & tapped density and angle of repose
Aims of my experiment:
1) To determine bulk density of powder A, B, C and D.
2) To determine tapped density of powder A, B, C and D.
3) To find the angle of repose of powder A, B, C and D.
Principle:
1) High bulk density of the powder indicates more efficient particulate packing or the powder is less aerated. These powders are less likely to be compressed than more aerated powder.
The bulk density and tap density of the powders is expressed with equation:
D (g/cm3) = Mass (g) , mass of powder used is constant, 5g.
Volume2) Low tap density indicating a low volumetric specific capacity of the material, having a disordered layered structure and also low crystallinity of the powder.
3) Compressibility indices of below 10 indicate excellent flow of powder while CI between 10 to 20 means the powder flows fairly well. The powder has a poor flowing if its CI is between 20 to 30. CI value of more than 40 indicates the powder is difficult to flow or do not flow at all.
Compressibility is the ability of the powder to deform under pressure.
The equation for Compressibility Indices,CI of the powders is:
CI = 100(Vo – Vf)
Vo4) Angle of repose of value less than 35 may be classified as free-flowing while those with angle of repose more than 45 can be either flow with difficulty or do not flow at all.
The angle of repose for each powder can be found using expression:
tan θ = h/r = x , where r is constant, 5.5cm
θ = tan -1 x
Result:
| Sample | Average bulk mass (g) | Average bulk volume (cm3) | Bulk density (g/cm3) | Average taped mass (g) | Average tapped volume (cm3) | Average tapped density (g/cm3) | Cl | Angle of repose |
| A(0.5mm) | 10.00 | 38.50 | 0.26 | 10.00 | 33.00 | 0.30 | 14.29 | 38.36 |
| B (0.7mm) | 10.00 | 32.70 | 0.31 | 10.00 | 29.40 | 0.34 | 10.09 | 37.50 |
| C (1.0mm) | 10.00 | 37.00 | 0.27 | 10.00 | 34.50 | 0.29 | 6.76 | 37.20 |
| D (1.4mm) | 10.00 | 27.70 | 0.36 | 10.00 | 27.00 | 0.37 | 2.53 | 34.80 |
Observation:
1) Granule A has the highest CI value.
2) Granule D has the lowest CI value.
3) Granule A has the highest angle of repose.
4) Granule D has the lowest angle of repose.
References
b) http://en.wikipedia.org/wiki/Powder_(substance)
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