Bulk density

BULK DENSITY

Principle

           The bulk density of the pesticide is determined as such and after compaction to find out the suitability of the material after movement or transport and storage. The bulk density after compaction is done by simulating the conditions that could occur on handling by allowing the container with pesticide to fall from a certain height.

Materials required

(i)             Graduated cylinder (100 ml), (ii) Felt pad and (iii) Balance.

Procedure

a) Bulk density before compaction

• Take a graduated cylinder and record the weight (W1 g)

• Allow the cylinder for five minutes untouched (Since there is some settling of dusts this minimum time lag is allowed) and add more pesticide if necessary to bring it to the 100 ml mark (V1).

• Record the weight of the cylinder with pesticide (W2 g).

• Calculate the bulk density by dividing the weight by volume.

b) Bulk density after compaction

• Stopper the cylinder with the substance.

• Drop it vertically twenty times through a height of fifteen cm into a felt pad resting on a hard surface or table.

• Take care that tapping is uniform and there is no breaking.

• Note the volume of the material after compaction (V2).

• Calculate the bulk density by dividing the weight by volume (after compaction).

Calculation

Bulk density before compaction

Weight of the cylinder=W1 g

Weight of the cylinder + pesticide=W2 g

Weight of the pesticide=W2 – W1 g

Volume of pesticide=100 ml (V1)

Bulk density=

Bulk density after compaction

Weight of the pesticide= W2-W1 g

Volume of the pesticide=V2 mL

Bulk density=W2-W1\V2

Per cent increase in bulk density

 after compaction               =(bulk density after compaction)-(bulk density berfore compaction) \bulk density                                                                                                                                                            berfore compaction

With regard to bulk density, different specifications are given for various pesticides. For example the compacted bulk density should not exceed by more than 60 per cent of the uncompacted bulk density in the case of BHC, DDT, Aldrin, Chlordane, Heptachlor and Malathion. In the case of copper oxychloride the bulk density should not exceed 2 g/cc.

Things to learn:

What is the ISI specification for the wettability of WD?

Why do you determine the bulk density of pesticide.