Improvement of anode and electrolysis procedure for industrialization of electrolytic manganese dioxide production at low temperature (75°C)

Graphite anode covered with titanium lattice (hybrid electrode) was found to be used as an anode in a large scale process of manufacturing electrolytic manganese dioxide (EMD) by electrolysis of MnSO4-H2SO4 solution using graphite anode and cathode, due to easy removal of deposited EMD from the anode surface without any mechanical destruction of the anode, which was very difficult in the case of using only graphite as an anode. The electrolysis at 75 degreesC provided an advantage of protecting the graphite anode from electrochemical corrosion in addition to heat enegy saving compared with electrolysis at 95 degreesC. Another electrolysis at 75 degreesC was done on a suspension bath process using titanium anode and MnSO4-H2SO4 solution with and without suspended EMD powder. The electrode in a suspesion bath was found to work for a long time without passivasion during electrolysis due to the surface modification by means of the suspended particles, while in nonsuspended bath it was passivated immediately during electrolysis. These results show that the hybrid electrode, and the titanium electrode in the suspension bath process can be used for large-scale EMD production at 75 degreesC.