Sonya Kalynuik HBSc thesis abstract

Cryptomelane was synthesized by refluxing KMnO₃ with Mn(NO₃)₂xH₂O and M(NO₃)₂xH₂O (M=Co, Cu, Ni, Zn, Pb) in various ratios in order to produce highly metalliferous cryptomelane.  Weight percents of 1.567%, 0.914%, 0.13%, 0.027% and 11.424% were obtained for Co, Cu, Ni, Zn, and Pb respectively.  With the exception of Pb (which substitutes for K), it is difficult to establish whether these metals are substituting for K or Mn, as the metals are in too small a concentration.  The metal content increases in order of Ni²⁺<Zn²⁺<Cu²⁺<Co²⁺<Pb²⁺.  Increasing the ratio of metals to potassium does not guarantee higher metal content.  It is apparent that most of the inputted metals are washed off during the filtration step, being less stable in the crystal structure than manganese or potassium.