Catalytic anodes for electrowinning-part:I effect of methanol addition

A significant reduction in energy consumption in metal electrowinning from sulphate solutions can be achieved by the use of catalyti: anodes in combination with methanol addition to the electrolyte. The effect of current density on methanol oxidation has knst udied on different types of catalytic anodes like Ru4f ilm electrode and sponge electrode. The effect of periodic current reversal on the anodic process has also been investigate

Gallium Recovery - Technological Alternatives

Bayer liquor is the pricipal source for gallium production. India is a large aluminium producing country and thus has a vast potential to produce gallium to the tune of 10 to 12 TPA from its five alumina plants. Various options are available for obtaining gallium from plant to plant through one of the following technologies viz, amalgam metallurgy, cementation of gallium with aluminium or aluminium gallium alloys, solvent extraction and ion exchange resins. The merits and otherwise of the various technologies will be discussed with reference to thier feasibility of commercial scale adoption in Indian Alumina plants, and their impact on the economy of alumina production. The world scenario of gallium production and consumption will also be dealt with

Catalytic anodes in electrowinning - inhibition of poisoning by manganese ions: Part II. Galvanic studies

The deactivation of catalytic anode caused by Mn2+ ion in electrowinning electrolytes has been studied under galvanostatic conditions. Gradual anode potential rise in presence of Mn2+ ion indicates the deterioration in the catalytic activity as a result of Mno2 formation on the electrode surface. The addition of soluble phosporous or arsenic compounds is found to restrict the rise in anode potential. Current efficiency studies made for Mno2 deposition in presence of arsenic or phosporous compound confirm the inhibiting tendency of these surface active substance on Mno2 formation. Surface characterization of polarised electrodes has also been made using scanning electron microscope