This test method applies to the determination of the compacted bulk density of a material and the determination of loss in the drying procedure.
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Principle of bulk density
A known weight of the sample is placed into a measuring cylinder and placed into a bulk density tapping apparatus. A sample is 'tapped' until the volume occupied by the sample is constant the volume is recorded, and the bulk density is calculated.
Safety of bulk densityÂ
Observe proper laboratory safety
rules, personal protection, and chemical handling procedures at all times.
Read MSDS before handling chemicals
and products.
Apparatus
250 mL measuring cylinder
Bulk density 'tapping' device
Analytical balance
What is the bulk density of aggregate and Bulk density of sand procedure?
1) Place a clean, dry 250mL measuring
cylinder on the balance, and tare the balance.
2) Place a plastic funnel in the top
of the cylinder and slowly add the sample through the funnel until there is approximately
200mL of product in the cylinder
3) Place the cylinder into a bulk-density
tapping apparatus.
4) Tap the cylinder 60 times by
lifting the cylinder to the drop height and releasing it. The cylinder should be
rotated a quarter turn on each lift.
5) Read off the exact volume, V1 taken
up by the sample.
6) Give the cylinder a further 15 taps
and read off the exact volume V2, taken up by the sample.
7) If V2 is not the same volume as V1
then repeat Step vi) until two consecutive equal readings are obtained
8) Record the final tapped volume of
the sample (mL).
9) Remove the funnel. Record the
sample weight (g).
Calculating bulk density
Bulk Density (g/mL) = Weight of Sample
(g)/Volume of Sample (mL)
Result:
Report the result in g/mL. Compare the
result to the specification.
Determination of loss on drying
This test method applies to any
substance which may be dried to a constant weight.
Principle of Loss on Drying
The weight lost from the material under
a defined set of conditions is both quantitative and reproducible. This loss in
weight is designated the Loss on Drying. A known weight of a material is placed
in an oven at a specified temperature for a specified time, or dried to a
constant weight, to remove all traces of free water in the sample. The sample
is then re-weighed to determine the loss in weight as a percentage of the
original sample weight.
Safety
Check to ensure that substances being
tested do not give off noxious fumes on heating.
Read MSDS before handling chemicals.
Observe normal laboratory safety rules
and chemical handling procedures.
Beware of hot apparatus. Use
appropriate handling techniques.
Equipment and Reagents
1) Weighing dishes or crucibles
2) Analytical Balance
3) Drying oven - fan forced variable
temperature 40 to 200°C
4) Desiccator
5) Tongs
The Procedure of Loss on Drying
1) Read the specifications of the
material to determine the conditions under which the test is to be conducted. Typically,
the sample weight, test temperature and drying time shall be defined for the
material.
2) Condition the weighing dishes at
the specified drying temperature by placing them in the oven for a minimum of two hours.
3) Cool the weighing dishes in the
desiccator for 30 minutes.
4) Weigh a clean and dry weighing dish
and note down the weight W1 (g) to 4 decimal places.
5) Weigh accurately into the dish the
specified weight of the sample, or if this is not specified approximately 2g,
and record the weight as W2 (g)
6) Dry the sample at the specified
temperature for the recommended time, or to constant weight if required.
7) Remove and cool in a desiccator for
30 minutes, then reweigh and record the weight after drying as W3 (g).
8) Determine the loss on drying as
below.
Loss on drying formula USP
Loss on Drying (% w/w) = (W2 - W1) - (W3 - W1) x 100/(W2 - W1)
Where :
W1 = Weight of the dish
W2 = Weight of the dish and sample
before drying
W3 = Weight of the dish and sample
after drying
Reference :
BP, USP, BPC, and other recognized texts
for raw materials.
