Loss on ignition

ESTIMATION OF LOSS ON IGNITION

Principle

         A known weight of the soil is ignited at 600  C and the loss in weight due to destruction of organic ,matter CaCO3,MgCO3 and loss of moisture is reported as loss on ignition.

Apparatus required

a.       Silica basin or crucible

b.      Chemical balance / Electronic balance

c.       Dessicator

Procedure

Ø  Ignite a silica basin or crucible over a rose-head flame for about 30mintes, cool in a dessicator and record its weight.

Ø  Transfer about 20 g of the soil sample into the silica basin and weigh accurately .

Ø  Ignite the contents of the basin over a rose – head flame for about 8 hours .

Ø  After the expiry of time , place the basin in a dessicator , allow it to cool and record the weight .

Ø  The loss in weight represents the loss on ignition together with the moisture lost at 110  

Calculation

Weight of empty silica basin

=

a g

Weight of silica basin+soil

=

b g

Weight of soil taken

=

(b-a) g

Weight of silica basin+soil after ignition

=

c g

Loss of ignition

=

(b-c) g

Loss on ignition expressed in per cent

=

Loss on ignition on moisture free basis

=

Where M= Moisture content