الفهرس 
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Abstract
This work aims to exploit the low-value Mn-bearing materials (low-grade Sinai manganese ore and ferromanganese slags) from Sinai Manganese Company, Egypt by hydro - and electro-metallurgical techniques. The ore fines have been leached by sulfuric acid in the presence of H2O2 as a reducing agent to produce manganese sulfate solution which is ready for the electrowinning process to deposit an electrolytic Mn-powder. The applied leaching conditions were; -150 µm ore particle size, 90°C electrolyte temperature, 1 hr. leaching time, 2 mole/L acid concentration, 0.4 mole/L H2O2, and 800 rpm stirring rate. Slag of ferromanganese was cruched and grinded to size of -150 µm then leached with the same conditions of low grade Mn ore. The effect of different parameters “e.g. temperature, stirring rate, current density, and anode-cathode distance” on the production process of electrolytic manganese powder were studied and evaluated. Finally, the optimum conditions for the proposed process will be determined. Local pyrolusite ore from Om-bogma, Sinai and slag of ferromanganese, have been treated by sulfuric acid leaching process using (H2O2) as reducing agent to produce manganese sulfate. Depending on previous work of leaching processes in this field, the best conditions were chosen for this work. There are no results for slag leaching becoase of the difficulty of leaching process which nead outoclave tecnque. The experimental runs have been carried out at temperatures of 30, 40, and 50°C, stirring rates of 0 ,100, and 200 rpm , and current densities of 200, 300, 400, 800, and 1200 A/m2. The applied optimum electrowinning conditions were 400 A/m2, 40 °C, 100 rpm and 10 cm anode/cathode distance. The electrowinning process was carried out with cathodic current efficiency up to 93.27%, specific energy demand in the range between 3.647 and 5.689 kWh/kg with powder productivity up to 0.880.