IMPROVEMENTS IN AND RELATING TO SELECTIVE SEPARATION OF METALS BY PYROLYSIS

1292839 Pyrolytic separation of metal values RUTHNER INDUSTRIEPLANUNGS AG and METALLURGIE HOBOKEN 27 Nov 1969 58114/69 Headings C1A and C1N Metal values in solution are separated pyrolytically by atomizing and spraying the solution which has been treated to convert ions in a lower valency state to a higher valency state, in cocurrent with a gas into a heated reactor to dehydrate the solution and pyrolyse the solute, whereby the temperature of the reactor is selected so as to render some of the anions insoluble whilst the others remain soluble and are extracted by leaching. The preferred anions are Cl-, NO 3 -, and SO 4 --. In the case of Clthe reaction is carried out at 2-400‹ C. and the Clis recovered as HCl; with NO 3 - the reaction temperature is 125-150‹ C. and the NO 3 - is recovered as HNO 3 and with SO 4 -- anions the reaction temperature is 600-650‹ C. and the SO 4 -- is recovered as H 2 SO 4 . The cations should be in their higher valency states before separation and this may be achieved by oxidizing the solution with Cl 2 , O 2 or air. Metals whose compounds are pyrolysed are Fe, Cr, Al, As, Sb, Sn, Mo, W, Ti, Ta and Nb, and may be separated from Ni, Co, Cu, Mn, Zn, Ca, Pb and Mg, whose compounds remain soluble.