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

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)2.2H2O]. 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 °C. PXRD measurements confirm the formation of K2CO3 and the results are in agreement with ATR − FTIR and thermal analysis.