Primus - a new process for the recycling of by-products and the prereduktion of iron ore

For many years the iron and steel industry has been in search of an economically interesting method for recycling iron and steelmaking by-products. The Primus process developed by Paul Wurth is a new technology enabling the treatment of dust and sludge from gas cleaning and waste water treatment plants in steelworks which until now have been problematic to recover. The Primus process is a reduction process, using coal for the reduction of metal oxides at 1100 °C in a multiple-hearth furnace. The by-products are transformed into a highly metallized Fe-concentrate which can be re-introduced into conventional production routes. The heavy metals contained in the by-products (Zn, Pb) evaporate and are extracted. The composition of the heavy metal fraction allows the sale of the heavy metals so that the by-products processed by Primus are completely transformed into useable products.