Thermal characterization of tetrabasic lead sulfate used in the lead acid battery technology

摘要

The thermal production of 4PbO center dot PbSO4 was comprehensively studied and characterized for two syntheses routes, i.e. either heating 3PbO center dot PbSO(4)H(2)0, or a mixture of 4PbO:PbSO4, in air to about 700 degrees C. In the 3PbO center dot PbSO4 center dot H2O approach, the formation of an intermediate amorphous phase occurred at around 210 degrees C with the loss of H2O from the hydrated structure. Formation of 4PbO center dot PbSO4 initiated at around 270 degrees C with predominantly 4PbO center dot PbSO4 and 13% residual PbO center dot PbSO4 existing at 700 degrees C. With the synthesis route of mixing a stoichiometric ratio of 4PbO with PbSO4, an intermediate phase of PbO center dot PbSO4 formed at around 300 degrees C, before the 4PbO center dot PbSO4 phase started to form at around 500 degrees C. Upon further heating, 4PbO center dot PbSO4 was the predominant phase with 8% of PbO center dot PbSO4 remaining. Both samples decomposed upon further heating to 850 degrees C. Powder neutron diffraction studies of the final 4PbO center dot PbSO4 products from the two different synthesis routes showed similar crystallographic unit cell lattice parameters with slight differences in the PbO:PbSO4 contents. This could possibly be linked to differences observed in the microscopic crystallite shapes from the two synthesis routes. (C) 2016 Elsevier Masson SAS. All rights reserved.