Measuring and managing dust and nanoparticulates in pyrometallurgical processing

Abstract

Combustion processes, comminution and materials handling can generate airborne particulates. Regulation of these particulates by the U.S. Environmental Protection Agency (U.S. EPA) is becoming progressively more stringent, and regulations will soon include “nanoparticulates,” which are particles finer than 100 nanometers (0.1 µm). Nanoparticulates are believed to have significant negative health effects due to their high surface area and reactivity. Although it was argued that nano particulate concerns were only important for combustion, studies at Michigan Technological University have shown that materials handling and comminution release significant quantities of nanop articles into the air. Laboratory studies have shown that the use of sodium metasilicate reduced airborne particles finer than 10 µm (PM₁₀) by 86% and particles finer than 2.5 µm (PM_2.5) by 80% for iron ore. Additional studies were conducted that revealed that nanop articulate emissions were present in the types of operations conducted at pyrometallurgical facilities.