Definition
Loss of ignition (LOI Loss on ignition) refers to the raw material that loses external moisture after drying in the temperature range of 105-110 ° C. The mass lost after burning for a long time under certain high temperature conditions accounts for the mass of the original sample. percentage. The high temperature environment here is detailed in the technical standards of various industries with the characteristics of different industries. The analysis of the loss of raw materials has its special significance. It characterizes the amount of gaseous products (such as internal water, SO2, CO2, etc.) released by physical evaporation or chemical decomposition after heating, for example, heating to 1000 ° C, drying in the temperature range of 105-110 ° C contained in the raw material does not evaporate The internal moisture will evaporate; the substances contained in the raw materials with sublimation points below 1000 °C will evaporate under heating conditions of 1000 °C; some substances with decomposition temperatures below 1000 °C will decompose and release decomposition. A substance having a boiling point lower than 1000 ° C is produced; under aerobic conditions, a combustible substance contained in the raw material is oxidized to generate a gas.
Through the measurement of LOI, it can be judged whether the raw material needs to be calcined in advance when used, so that the raw material composition is more stable. According to the components obtained by chemical analysis, the purity of the raw material can be judged, and the fire resistance performance can be roughly calculated, and the mineral composition can be roughly calculated by the relevant phase diagram.
For example, in the analysis of the refractory material, in addition to the content of the main component oxide and the auxiliary component, the amount of loss on ignition is usually measured. It characterizes the amount of gaseous products (such as H2O, CO2, etc.) and organic matter produced by the thermal decomposition of the raw materials, so that it can be judged whether the raw materials need to be calcined in advance to ensure the volume stability of the raw materials. According to the components obtained by chemical analysis, the purity of the raw material can be judged, and the fire resistance performance can be roughly calculated, and the mineral composition can be roughly calculated by the relevant phase diagram. The chemical composition analysis of refractory raw materials is carried out according to special methods. It has been stipulated in international standards and national standards. In recent years, chemical analysis methods have been developed in the direction of accelerating analysis speed and improving analytical precision, such as complex titration. Colorimetric analysis, flame photometry, spectral analysis and X-ray fluorescence analysis.