The dissolution behavior of lead plates in aqueous nitrate solutions

The dissolution behavior of metallic Pb plates in aqueous neutral sodium nitrate and ammonium nitrate solutions was investigated. Using a rotating disk method, the rate of dissolution was measured by weight changes in the disks for nitrate concentrations of 0.01-0.2 mol dm^-3, at rotation speeds of 100-800 rpm and 60-90°C. In ammonium nitrate solution, the dissolution rate was mainly determined by the chemical reaction at temperatures higher than 60°C and by NH₄NO₃ at concentrations higher than 0.05 mol dm^-3. The dissolution rate in NaNO₃ solution was much slower than that in NH₄NO₃ solution. X-ray photoelectron spectroscopy analyses showed the formation and compositional differences of a passive oxide layer containing nitrogen compounds on the lead surface in both nitrate solutions.