Loss on ignition describes the process of measuring the weight change of a sample after it has been heated to high temperature causing some of its content to burn or to volatilise.
Weight change of the sample is monitored during the heating process and this is required, for example, in the determination of organic matter content in materials such as sediment, sludge, soil and waste. Inorganic materials such as cement, lime, calcined bauxite and refractories can also be tested by loss on ignition.
For loss on ignition tests Carbolite Gero offers, amongst others, the AAF-BAL furnace with integral balance or the IOR iron ore reducibility furnace which has a balance to measure the loss in mass of iron ore samples.
Loss on drying is a widely used test method to determine the moisture content of a sample, although occasionally it may refer to the loss of any volatile matter from the sample.
Loss in drying does not usually refer to molecularly bound water or water of crystallisation.
For loss in drying (LOI) applications Carbolite Gero offers a sample weighing modification for many of its standard products. A modified HTMA 6/95 high temperature oven with continuous sample weighing option is illustrated on the right as an example.
This is commonly used to determine selected characteristics of materials that exhibit either mass loss or gain due to decomposition, oxidation, or loss of volatiles (such as moisture). For thermogravimetric analysis the weight change of the sample must be continually monitored during the heating process.
Carbolite Gero manufactures a number of standard products with an integrated weighing balance such as the AAF-BAL for organic loss on ignition, the CWF-BAL for inorganic loss on ignition and the ABA 7/35B for asphalt binder content measurement.
Custom designed products can also incorporate an integrated balance for loss on drying, loss on ignition and thermogravimetric analysis. One example, illustrated on the right, is a custom-built retort furnace up to 900°C for 250kg loads, which includes a balance with 5g accuracy and measures mass loss under inert gas atmosphere.