The raw materials are weighed and delivered to the melting furnace. For stone wool this is the volcanic rock and for glass wool it is the recycled glass cullet.
The mineral wool is then heated to around 200°C to polymerize the binder and gives the strength and stability to the insulation.
The raw materials are melted in the furnace at high temperatures, between 1,300°C to 1,500°C. The smoke created during this process if filtered to minimise any environmental impact.
The mineral wool is cut to the required size and shape, either into rolls, batts or boards. Trimmed edges and other mineral wool scraps are recycled back into the production process, which further reduces inputs and energy requirements.
The molten glass/stone from the furnace are spun into fibres. For stone wool the molten rock falls onto rapidly rotating flywheels and for glass wool the molten glass are drawn through tiny holes in rapidly rotating spinners. This process shapes the molten glass/stone into fibres
The mineral wool is further processed for other applications such as sectional pipes and pre-laminated boards.
Binding agents are added to bond the fibres.