RATE OF CHLORINATION OF METALS AND OXIDES .2. IRON AND NICKEL IN HCL(G)

The rates of chlorination of iron (810 to 1175 K) and nickel (850 to 1340 K) in HCl (gas) were measured. In all cases, rates were controlled by transport through the gas film boundary layer at the surface of the sample. At low temperatures and high pressures of HCl the condensed chlorides form FeCl//2 (solid or liquid) and NiCl//2 (solid), and the steady state weight loss is controlled by diffusion of metal chlorides through the gas film boundary layer. The temperature dependence of the rates is essentially the same as for the vapor pressure of the chlorides, viz, 37 kcal for iron and 53 kcal for nickel. At high temperatures the condensed chlorides do not form, and the rates are controlled by the countercurrent diffusion of HCl and the gaseous chlorides through the boundary layer for both metals.