THE APPLICATION OF NONISOTHERMAL METHODS OF KINETIC-ANALYSIS TO THE DECOMPOSITION OF CALCIUM HYDROXIDE

In this paper, the kinetic analysis of the thermogravimetric curves for the decomposition process of calcium hydroxide (under dry nitrogen atmosphere) is performed. Various forms of non-isothermal methods of analysis for determining the kinetic parameters are used. The calcium hydroxide samples were a commercial sample and samples prepared by reacting calcium nitrate with sodium hydroxide solutions at concentrations of 1 and 0.1 M. All the methods show that in the heating rate ranges 5-40-degrees-C min-1, the most probable reaction mechanism for commercial calcium hydroxide is the Avrami-Erofeev equation (A) with n = 1.5 (i.e. A1.5), for calcium hydroxide prepared from 1 M solutions is A2 and for calcium hydroxide prepared from 0.1 M solutions is Al.5. The data also show that the distribution of particles and the change of the particle size are factors which affect the reaction mechanism.