Cyanide Evolution from a Potassium Gold Cyanide Plating Bath

摘要

When a gold plating console was installed in a production area at the General Electric Neutron Devices Department (GEND), the console was placed adjacent to a 10% H sub 2 SO sub 4 activation bath. An experiment was made to measure the amount of hydrogen cyanide gas released as a result of the accidental addition of sulfuric acid to the gold bath. Similar hydrogen cyanide gas evolution data were obtained from the addition of either dilute sulfuric acid or concentrated sulfuric acid. Results show hydrogen cyanide gas release was a function of the plating bath pH. Air samples collected over a portion of the gold bath at pH 5.6 and at either room temperature or at a 70 exp 0 C operating temperature were found to contain 2 mu g/1 hydrogen cyanide. Air samples collected over the bath sample at pH 4.1 to 4.3 contained 40 mu g/1 hydrogen cyanide. A rapid increase in hydrogen cyanide was found in air samples collected over plating bath samples below pH 2.5. A quantity of reagent grade concentrated sulfuric acid was added to the test bath, which was equivalent to the addition of a 9-pound bottle of the acid to the 30-gallon production bath. Air samples were found to contain 1400 mu g/1 of hydrogen cyanide. (ERA citation 05:013979)