THERMAL-BEHAVIOR AND KINETIC-ANALYSIS OF THE THERMOGRAVIMETRIC DATA OF DOUBLE AMMONIUM-SULFATE HEXAHYDRATE SALTS OF MN(II), FE(II), CO(II),NI(II) AND CU(II)

The thermal behaviour of double ammonium sulphate hexahydrates of Mn(I I), Fe(II), Co(II), Ni(II) and Cu(II) was studied in air using TG and DTA techniques. X-ray powder diffractometry was used to identify the s olid decomposition products. The thermal stability of these double sal ts in the solid state is discussed and the mechanism of their decompos ition is also suggested. A kinetic analysis of the TG data was perform ed by using Jeres' modification of the Freeman-Carroll method to deter mine the apparent activation energy and order of reaction.