Thermal dehydration and decomposition of FeCl3 center dot xH(2)O

Abstract

Thermal dehydration and decomposition characteristics of Fe(III) chloride hydrate have been studied by both isothermal and non-isothermal methods. Alter the initial melting at 35-40 degrees C both dehydration and decomposition of the salt proceed simultaneously at temperature above 100 degrees C. At 250-300 degrees C a stable hydrated Fe(OH)(2)Cl is formed representing the first plateau region in the TG curve. Around 400 degrees C, a second plateau is observed corresponding to the formation of mostly Fe2O3 which however retains some OH groups and CT ions. However, these temperature ranges vary with the TA equipments used. Chemical analysis of the products of decomposition at temperatures above 140 degrees C also gives evidence for the formation of FeOCl which on hydrolysis in water gives FeCl3 in solution. The FT-IR spectra suggest the presence of structural OH groups even for samples calcined at 300-400 degrees C. The XRD patterns of the products of decomposition in the temperature range 160-400 degrees C indicate the presence of beta-FeOOH, some unidentified basic chlorides and alpha-Fe2O3.