INFLUENCE OF PBO MODIFICATION ON THE KINETICS OF THE 4PBO.PBSO4 LEAD-ACID-BATTERY PASTE FORMATION

The influence of PbO modification on the formation of 4PbO·PbSO4 paste is determined by X-ray diffraction analysis and scanning electron microscopy. The paste was prepared from tetragonal PbO, orthorhombic PbO and several mixtures of both oxides at 80° C and a H2SO4/PbO ratio of 6 wt%. The reaction scheme of 4PbO·PbSO4 formation depends on the PbO modification. When tetragonal PbO is used, 3PbO·PbSO4·H2O crystals are obtained first and then 4PbO·PbSO4. If the initial oxide is orthorhombic PbO, PbSO4, PbO·PbSO4 and 3PbO·PbSO4·H2O are formed successively. When the correct ratio of 3PbO·PbSO4·H2O, orthorhombic PbO and tetragonal-PbO is achieved in the paste then 4PbO·PbSO4 formation begins. This ratio is reached most quickly if tetragonal PbO is present at 30-60wt% in the initial mixture of both modifications. © 1979 Chapman and Hall Ltd.