NEW BOLIDEN is the third largest copper metals supplier in Europe and handles all process stages from mining via smelting until recycling for copper, zinc and other valuable metals. The Rönnskär plant located in Skelleftehamn in northern Sweden houses one of the largest copper smelters of its kind in the world. Beside copper zinc, clinker, lead and precious metals are produced in the Rönnskär plant.
Controlled zinc smelting and reduction
The zinc smelter in Rönnskär is energised by burners fuelled with pulverized coal. Three ABB pulverisers feed two burners each. In total there are 52 pipes which bring the fumes into the smelter. The burners are operated with lean air to produce carbon monoxide required for reduction of the zinc oxide to pure zinc. Boliden uses MECONTROL Coal to control fuel flow and fuel concentration to the burners for a controlled combustion. If the air to fuel ratio is too lean the energy production is not sufficient to keep the temperature at the required level, if too rich the zinc will not be entirely reduced. The PROMECON system measures velocity by a drift free correlation based technology and the dust concentration by microwave resonance in the feeder pipes.
Beside the coal flow meters NEW BOLIDEN uses PROMECON technology to measure the Mill airflows to control the mill performance. The airflow trough the mill is required to control the particle size and the mill exit temperature depending on coal type, moisture content and coal feed.
Efficiency & environment
Finally settings for mills, classifiers and fuel distribution could be optimised and fuel to air ratio the firing can be monitored for continuous high quality operation. The Rönnskär plant not only houses one of the largest copper smelters but operates also an energy efficient and environmental friendly zinc smelter.
New Boliden Rönnskär Zinc Furnace - Case Study