Curing position

Tank formation means that the cured positive and negative raw plates are inserted alternately in special tanks filled with fairly dilute sulfuric acid (generally in the range 1.1 to 1.15gcm 3) and positive and negative plates are connected, a number of each, in parallel with a rectifier. The formation process means that the active material of the plates is electrochemically transformed into the final stage, namely ... 

The role of this test is as a screening procedure that must be supported by some other tests when results cure positive. Its biggest limitation is the uncertainty of whether the variants in sperm result from mutation. A few mutations have been induced that produce a high proportion of sperm abnormalities in Pj sons. It is unlikely that fertilization with a malformed sperm constitutes an increased genetic hazard to the fertilized egg.509... 

Fig. 3.5. Changes in chemical composition of cured positive plates during soaking in 1.05, 1.15, or 1.25 rel. dens. H2SO4 [6].

Positive plates need much more time to form than negatives. The reason for this is the dielectric behaviour of the cured positive paste. Oxidation of the bivalent lead compounds in the paste and formation of the Pb02 positive active mass passes through a number of chemical reactions, some of which proceed at a low rate, which retards the technological process of formation of the positive plate. In an attempt to accelerate the formation process, additives to the positive paste have been looked for, which are characterised by electro-conductive properties and stability in sulfuric acid. These additives create an electro-conductive network in the paste and the process of oxidation proceeds simultaneously within a large paste volume, thus accelerating plate formation. 

Cured positive plates are treated with ozone gas in a chamber, as a result of which PbO is oxidized to Pb02, which forms a thin coating on the surface of unformed plates. During formation, the lead dioxide layers on the two plate surfaces grow simultaneously towards the plate s interior. Consequently, the formation time and the energy input are reduced substantially. However, this method is too expensive and requires special corrosion-resistant chambers. 

FIGURE 3.5 Electrochemical and chemical reactions proceeding during the first stage of formation of the cured positive paste. (From M. Dimitrov, and D. Pavlov, J. Power Sources, 93, 234, 2001.)... 

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