ICB 26814
INSTITUTO INTERDISCIPLINARIO DE CIENCIAS BASICAS
Unidad Ejecutora - UE
artículos
Título:
Thermal and structural analysis of the reaction pathways of α-spodumene with NH4HF2
Autor/es:
ESQUIVEL, MARCELO R.; ROSALES, GUSTAVO D.; RESENTERA, ALEXANDER C.; RODRIGUEZ, MARIO H.
Revista:
THERMOCHIMICA ACTA
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2020 vol. 689
ISSN:
0040-6031
Resumen:
In this work, the thermal and microstructural analysis of the reaction pathways of α-spodumene with NH4HF2 at low temperatures is presented. The thermal behavior ofNH4HF2, mixtures α-LiAlSi2O6/NH4HF2 and by-products (NH4)3SiF6·F/(NH4)2SiF6, are analyzed by simultaneous thermogravimetry and differential thermal analysis (TGDTA).The study of the crystallite size and lattice strain in the solids is carried outusing X-ray diffraction (XRD). The obtained results indicate that the heating rate hasa remarkable influence on the processes. At low heating rates, 1 K/min, the reactionbetween the mineral and NH4HF2 begins at about 351 K and is completed around426 K, approximately. The obtained products are LiF, (NH4)3SiF6·F, (NH4)3AlF6, NH3and H2O. In the 368 to 429 K temperature range, the unreacted NH4HF2 is removedand (NH4)3SiF6·F starts to decompose to generate (NH4)2SiF6. Finally, (NH4)2SiF6and (NH4)3AlF6 sublimate and decompose at 433 and 493 K, respectively. The mainfinal product is a LiF/AlF3 mixture at 533 K.
