Rock slag is a very hot dry material that is generated during the Ironmaking process. This material is transported via truck from the Blast Furnace and stockpiled. Historically, dust emissions were generated when the material was tipped from the back of the truck. In order to supress dust emissions, recycled water was sprayed on the slag during tipping.
A number of investigations have been conducted to reduce dust emissions even further. A parallel trial of salt-based and polymer-based dust suppressants was conducted to determine the most effective solution. Both products were tested through various weather conditions. It was concluded that the polymer-based dust suppressant was more effective. The polymer-based coating forms a crust over the surface of the stockpile which is effective for up till several months. This has resulted in a significant saving of recycled water consumed as intermediate dust spraying is no longer required.