AbstractThe- aim of the research was to determine the effect of ball mill produced lead oxide powder on freshly produced positive paste. This knowledge would enable the company to manufacture positive electrodes with consistent composition for use in sealed, valve regulated, lead (Pb)/sulphuric acid (H 2SO4) batteries.
Positive battery paste is predominantly composed of lead oxide powder. The company considered that the composition of freshly mixed positive paste was dependant on the quality of lead oxide powder. However, this investigation of lead oxide quality variations has revealed no clear correlation with paste density fluctuations.
Before tests could commence to assess the effect of lead oxide quality on positive paste composition, an explanation for previous lead oxide quality variations and the lack of correlation with positive paste density had to be determined. The variations in lead oxide quality were assumed to be the result of either the analytical errors associated with the test procedures used to assess quality by the oxide mill operators or ball mill process variables varying unnoticed. Both hypotheses were extensively studied and it was determined that measurement errors were the main problem. An alternative analysis technique, referred to as the acetic acid method, was introduced to solve the problem.
Once the reason for the lack of correlation between lead oxide quality and positive paste composition had been determined, the effect of lead oxide quality on paste composition was determined. A series of tests referred to as fractional factorial optimisation tests were performed using various batches of lead oxide powder. The composition of each trial positive paste mix was assessed. Through the use of regular analysis techniques, the characteristic lead oxide required to produce a positive paste with a well defined narrow density range was determined and the ball mill process was set up to produce only the required type of oxide.
|Date of Award||Jun 1995|
|Supervisor||Peter Hall (Supervisor)|