Conclusions


Calcium Sulfate - CaSO4

  • The lead sulfate don't crystallize every time on the calcium sulfate crystals;

  • After the "reduction" phase the calcium sulfate crystals remains on the surface;

  • The crystallization of the lead sulfate appear later than in barium sulfate or strontium sulfate.

Bismuth Sulfate Bi2(SO4)3

  • The crystallization of the lead sulfate crystals is not influenced by the additions of bismuth sulfate;

  • The bismuth sulfate crystals catalyze the formation of the H2 molecules;

  • The bismuth sulfate crystals hydrolyze (Bi sulfate absorb some OH ions) and during th polarization the Bi metallic can appear.

Others Sulfate

  • It can be interesting to extend the investigations to some other sulfates in order to understand the phenomena which occur at the negative electrode.