Development Of A New Automatic Cement Raw Materials Differential Thermal Analyzef

Known to all, it is very important to provide cement raw materials (CRM for short) with well-proportioned heat in the manufacture of upright kiln. In this paper, the ideology of DTA is introduced, and an exact, fast, and convenient CRM heat analyzer-CRMDTA is developed by efforts.Through basal theory and experiment discussions, the following are obtained : There is a distinct difference more than 150 between the combustion exothermic reaction of coal and the decompounding endothermic reaction of CaCO3, which is the main component of CRM, while few thermal reactions happen during the area of such difference in the CRM without coal; There is a one-to-one relationship between DTA curve acreage and CRM heat. Thus the idea is advanced to test CRM heat by DTA.Some important components of CRMDTA are selected or designed in this paper. We select Ni/Cr alloy resistor as element together with ceramic embedding hearth; select small flat-and-disc heat-even hubby ceramic sample holder, select Ni/Cr & Ni/Si thermoelectric couple (Type K) as thermoscope with threads 0.5 mm in diameter which is installed in the middle of the holders symmetrically; select aluminum silicate fire-retardant fiber as materials for heat preservation; design some hardware, for example temperature controller & transporter, signal amplifier etc; design controlling curve to heat stove; and introduce the method of least squares nonlinear regression and subsection function to deal with data.In order to obtain the reasonable operation conditions and operation curve, we have also done many theory analysis and experiment discussions. We select CRM without coal as reference; select semi-dynamic atmosphere to operate machine; use the method fixing the temperature of hearth and that of sample holders when the analysis begins, which ensures the consistency ofheating samples; adopt the DTA curve of "AT-t" to analyzing CRM heat,which decreases possible influences from the fluctuation of heating velocity; draw conclusions that CRM proportion and granularity influence the analysis little, but not CRM moisture and coal species; advise that there be a warm-up to the CRM with much moisture before analysis and a modification to theCRM with variable species of coal; then obtain the feasible operation conditions and operation curve (together with the curve function).With the advantages of right principle, simple structure, easy operation, good veracity, ideal reappearance and perfect security, CRMDTA can meet the need of heat supply control better for the characteristic upright kiln manufacture of our country, and play an important role in adapting ISO standard and carrying out the continuable stratagem for cement industry. It has a wide application in the field of thermal analysis, too!...