Interaction of zincate with additives turbidimetric, IR and Raman spectralanalyses

The interaction of zincate with additives, viz., alkaline earth oxides, cad mium oxide, nickel hydroxide, cobalt hydroxide bismuth oxide, sodium carbon ate, and lithium hydroxide is investigated by turbidimetry and Raman spectr oscopy. From the pattern of dependence of turbidity on additive concentrati on, thr additives can be classified into three groups: (i) BeO, CdO, MgO, N i(OH)(2), Co(OH)(2); (ii) CaO, BaO, SrO; (iii) LiOH, Bi2O3, Na2CO3. An iden tical grouping of additives has been discerned from Raman spectral analysis . Turbidimetry is a simple inexpensive technique for understanding the proc esses taking place between the additives and the zincate solution. Products of electrochemical dissolution of zinc in 4 M NaOH containing alkaline ear th 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. (C) 2000 E lsevier Science S.A. All rights reserved.