Intermediate products characterization and thermal decomposition mechanism of potassium tetraoxalate during in-situ synthesis of potassium carbonate

摘要

Current studies describe the application of simultaneous TG-DTA-FTIR techniques in the in-situ synthesis of potassium carbonate (K2CO3) from the thermal decomposition of potassium tetraoxalate dihydrate [KH3(C2O4)(2)center dot 2H(2)O]. Progress of the decomposition reactions with increasing temperatures was monitored online through TG mass loss, corresponding heat effects and evolved gases. Sequential formation of anhydrous potassium tetraoxalate, potassium hydrogen oxalate [KHC2O4] and potassium oxalate [K2C2O4] was confirmed using thermal, ATR - FTIR and PXRD measurements. The intermediate potassium oxalate undergoes structural transformation and then decomposes to potassium carbonate by the temperature of 600 degrees C. PXRD measurements confirm the formation of K2CO3 and the results are in agreement with ATR - FTIR and thermal analysis.