Anhydrous borax is an important
industrial product obtained either from borax decahydrate or borax
pentahydrate. The kinetics of dehydration of borax pentahydrate using TG and
DTA techniques was studied. It was shown that 2.25 mole of the crystal water
removes in the first step with zero order kinetics in the temperature range
between 382 and 433 K. The removing of the remaining water was completed at 733
K with the second order reaction in the second steps. Arrhenius form of
reaction rate constant for step 1 and 2 were also determined. They are: and
respectively, where T is absolute temperature in K.
The total activation energy calculated
from Coats-Redfern method was found to be 147.3 kJ/mol. It was also found that
this value is in a good agreement with those calculated from Kissinger and
Doyle methods.
Subjects | Engineering |
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Journal Section | Articles |
Authors | |
Publication Date | September 30, 2017 |
Published in Issue | Year 2017 Volume: 18 Issue: 3 |