Abstract: Application of on-line infrared CO₂ gas analyzer（instrument method） in carbonate production to determine the concentration of CO₂ was presented.The principle and characteristics as well as the advantages and disadvantages of instrument method in comparing with conventional flask absorption method were introduced.It′s suggested that on-line infrared CO₂ gas analyzer should be installed in the location behind the kiln gas purification and compression of the calcination procedure or before the carbonization procedure，i.e.installed in the vicinity of the CO₂ gas compression tank.Comparing with the conventional flask absorption method，instrument method has the advantages of in situ，on-line，nondestructiveness，rapid determination speed，high precision，and small error etc.in determining the concentration of CO₂ during the carbonate production.

Key words: on-line infrared gas analyzer, carbon dioxide, monitoring, carbonate, process adjustment and control