The invention discloses an online
blast furnace soft melting zone root position monitoring method. The method comprises the steps that the average density of
heat flow passing through furnace linings is calculated by collecting the flow rate and temperature of cooling media in
layers of cooling equipment of a
blast furnace, the
temperature difference between an inlet and an outlet, and other data; the average temperatures of the hot surfaces of all the
layers of the furnace linings are calculated by analyzing the
heat resistance of all parts between the cooling media and the hot surfaces of the furnace linings and combining the average
heat flow density, the temperatures are used as the central point temperatures of the hot surfaces and subjected to interpolation or fitting, and thus, longitudinal temperature distribution of the heat surfaces of the
blast furnace is obtained; the upper
boundary temperature and the lower
boundary temperature of a soft melting zone are calculated according to the
phase composition of a to-be-smelted object, and the upper boundary position and the lower boundary position of the root of the soft melting zone can be determined by combining the longitudinal temperature distribution; and thus, online monitoring of the root position of the soft melting zone of the blast furnace can be achieved through online monitoring of the low rate and temperature of the cooling media, the
temperature difference between the inlet and the outlet, and other data. The online blast furnace soft melting zone root position monitoring method has the advantages that timeliness is good, calculation is easy, and equipment investment is small; information including longitudinal temperature distribution of the heat surfaces of the furnace linings, the root position of the soft melting zone and the like can be monitored in real time; and theoretical direction is provided for optimized operation of the blast furnace and smooth production.