RATE OF OXIDATION OF SULFUR-DIOXIDE IN PLUME OF A NICKEL SMELTER STACK

Some results are presented on the rate of formation of sulfates from SO2 in the plume of the 380 m stack at a Ni smelter at Copper Cliff, Canada. The plume was sampled by aircraft, during Sept. 1974 and June 1975, using glass fiber and chemically impregnated cellulose filters to collect aerosols and SO2, respectively. Within the first 100 km or so of the stack, usually < 10% of the S in the plume is in the form of sulfate. Oxidation rates were similar in Sept. 1974 and June 1975, and were generally < 3% h-1. No temperature or humidity effects were detected in the data. A slight decrease in the oxidation rate with plume age was apparent, but the experimental scatter was too large to allow any definite conclusions. An average value of about 1% h-1 seems representative.