Study on Roast Reaction Kinetics of Baotou Concentrate of Rare Earth with 15/100 Na_2CO_3 Additions

摘要

The research on the mechanism of the roast reaction of Baotou concentrate of rare earth with 15/100 Na_2CO_3 additions was carried out through thermal, X-ray diffraction and chemical analysis. Bastnaesite (RECO_3F) was first decomposed into REOF at 623～741 K, then Monazite (REPO)4) reacted with Na_2CO_3 was decomposed into RE_2O_3 and produced Ca_8Nd_2(PO_4)_6O_2 at 853～928 K. The kinetics parameters of the roast reaction were calculated. The results of the calculation were as follows: at 623～741 K, E=152 kJ.mol~-1, n=0.77, A=1.11 x 10~12 s~-1. mol~-1, k=1.102(T=705 K), and at 853～928 K, E=232 kJ. mol~-1, n=1.16, A=1.11 x 10~9 s~-1mol~-1, k=1.07 x 10~4 (T=915 K). The equation of the mechanism of the roast reaction is F_1=-ln(l-α) at 623～741 K and 853～928 K according to TG curves.