Formation of plates prepared with 4BS-cured pastes

Formation of plates prepared with 4BS-cured pastes 

As mentioned above in Section 3.2.4, only a superficial layer of 4BS crystals (1-2 pm thick) is sulfated during the soaking procedure. Further sulfation stops thereafter. If the diameter of 4BS crystals is kept constant (at about 10 pm), the length does not influence the efficiency of the formation process [9]. In fact, the formation efficiency depends very strongly on the diameter of the 4BS crystals [9,12,49], 

The time for formation of the 4BS crystals depends on their thickness. The latter, in turn, is determined by the method of production of these crystals. The following technologies for the production of 4BS-cured pastes have been put into practice. 

80°C and 3BS crystals are converted into 4BS crystals of irregular shape (Fig. 3.38), with good connection between themselves and with the current-collector. Formation of such pastes takes more than 48 h. This technology is used for the production of all types of positive plates. If the time of steam treatment is extended to 8-10 h and the temperature of the plate is higher than 90°C, the resulting 4BS crystals are very thick and the formation of such pastes requires several days. When this method is applied to the manufacture of positive plates for stationary batteries, service lives of over 15 years are achieved. 

4BS crystals are obtained during paste preparation at temperatures higher than 80°C [51]. This technology yields long, well-shaped, 4BS crystals with a thickness that varies depending on the time of paste mixing and the temperature of paste preparation. When the paste is mixed for 10-20 min, the crystals are 2-4 pm thick and require 20-30 h for formation. The PAM 

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Formation of Plates Prepared with 4BS Cured Pastes... 

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