Kinetic Analysis Of Multi-step Thermal Decomposition Reaction Of Calcium Carbonate

Exploring the nature of chemical reactions of substances has important practical significance for understanding and controlling the chemical reaction process and better applying it to industrial production.The main purpose of non-isothermal kinetics of solid reaction is to determine the mechanism model,activation energy and pre-exponential factor of solid reaction,and to quantitatively describe the solid reaction process through kinetic parameters,so as to provide scientific basis for reactivity of solid and determination of production technology.As a typical solid reaction,the thermal decomposition reaction of calcium carbonate plays an important role in the control of alkalinity in the metallurgical industry.The kinetic process of the thermal decomposition reaction has been widely concerned and studied.Although the chemical reaction quantification formula of calcium carbonate decomposition shows that there is only one step in the decomposition process of calcium carbonate,the thermal decomposition process of calcium carbonate involves random nucleation and subsequent growth of solid products,interfacial reaction,diffusion of gas products and heat transfer,etc.In terms of the nature of the thermal decomposition of calcium carbonate,the thermal decomposition is a complex solid reaction.In this paper,different experimental variables were designed to study the thermal decomposition reaction kinetics of calcium carbonate,and the following conclusions were drawn:(1)The increase of heating rate,the increase of particle size and the increase of impurities content will increase the initial and end temperatures of the thermal decomposition reaction of calcium carbonate,and the temperature range of the reaction will also become larger.(2)Comparing the kinetic data of thermal decomposition reaction with differentheating rates,impurity content and particle size of calcium carbonate,it is found that the change of particle size has the most influence on the decomposition reaction process.(3)The influence of pore structure generated during the thermal decomposition ofcalcium carbonate cannot be ignored.(4)The stochastic hole model was optimized by using the kinetic model optimization theory,and the P-GDC(Pore-Growth-Diffusion-Contracting)kinetic model,which can better predict the thermal decomposition process of calcium carbonate,was obtained.Its mathematical form is as follows:...