Recent Developments

Case study - baghouse dust

A case study presented at a technical symposium on aluminum processing showed how companies can unexpectedly find themselves facing major disposal costs and fines if baghouse dust contains even part per million levels of selenium.

Environmental scientist Karen Hagelstein explained that if baghouse dust releases more than 1 mg/L of selenium by EPA's Toxicity Characteristic Leaching Procedure which is designed to simulate leaching of land-filled waste, it has to be treated as hazardous waste. This threshold is easily reached when selenium volatilizes at the temperatures in melts, producing particulates that are then captured in baghouse dust from furnaces.

She described how one metal recycling company, unaware of the selenium levels in the baghouse dust it was processing, faced more than $65,000 in state fines and the cost of reprocessing the dust as hazardous waste at an RCRA landfill. In addition, the company had to begin health monitoring of its employees and hold hazardous waste training sessions. These costs are ongoing.

Other aluminum consumers could face similar baghouse-dust problems, which could put pressure on scrap processors and brokers to limit the amount of selenium-containing products they handle, Hagelstein said. However, because there is no inexpensive test to detect the presence of selenium in metal, "the best solution might be for aluminum and steel producers to avoid using selenium-contaminated manganese in their metals." That would require using selenium-free manganese, which is readily available.

Further information regarding this case study may be found in the Recent Research section of the website under Uses of Selenium-contaminated Manganese in Aluminum and Steel Manufacturing.