SOME STRUCTURAL AND TEXTURAL ASPECTS OF TRIBASIC LEAD SULFATE PRECIPITATION DURING THE MIXING OF LEAD-ACID-BATTERY POSITIVE PASTE

The reaction between PbO and H2SO4 in water leading to the formation o f tribasic lead sulfate hydrate was studied using pH measurements, x-r ay diffraction, scanning and transmission electron microscopy, and inf rared spectroscopy. We examined the effect of different parameters suc h as temperature, starting composition, Pbo source, order of the mater ials addition, and presence of carbonates, on PbO-H2SO4 reaction. From this study, a mechanism is proposed for the reaction. It explains why , by mixing PbO and H2SO4 in water, the tribasic lead sulfate cannot b e obtained as a pure phase. Some unreacted PbO always remains at the e nd of the reaction.