Interaction of zincate with additives turbidimetric, IR and Raman spectral analyses

The interaction of zincate with additives, viz., alkaline earth oxides, cadmium oxide, nickel hydroxide, cobalt hydroxide bismuth oxide, sodium carbonate, and lithium hydroxide is investigated by turbidimetry and Raman spectroscopy. From the pattern of dependence of turbidity on additive concentration, the additives can be classified into three groups: (i) BeO, CdO, MgO, Ni(OH)2, Co(OH)2; (ii) CaO, BaO, SrO; (iii) LiOH, Bi2O3, Na2CO3. An identical grouping of additives has been discerned from Raman spectral analysis. Turbidimetry is a simple inexpensive technique for understanding the processes taking place between the additives and the zincate solution. Products of electrochemical dissolution of zinc in 4 M NaOH containing alkaline earth oxides, SnO, CdO, Ni(OH)2, CO(OH)2, or LiOH have been analysed by IR spectroscopy. The effect of heat treatment of the products on IR spectral pattern is described in the light of thermogravimetric analysis.