The iron and steelmaking industry generate annually huge amount of by-products and wastes in terms of slag, dust, sludge, mill scale etc. In addition to these our industry also consumes a lot of energy and release a targe quantity of green house gases such as C02 and NO*. A large number of environmental technologies have been pilot tested at Swerea MEFOS in the past 20 years. These include the long term projects for C0 2-reduction and energy saving technologies, control of dioxin emission and various pyro-metallurgical processes for treatment of wastes and by-products generated by the steel industry. This paper will highlight some of the pilot and demonstration projects carried out at and by Swerea MEFOS. These projects include the IPBM-process, for recovery of valuable metals such as V, Cr and Zn from slag and dusts, the REZIN concept for zinc recovery from EAF dust, Preheating and surface cleaning of scrap using ASR. The experiences at Swerea MEFOS have shown that pilot testing is one of the most essential parts of the development of advanced green technologies for the steel industry.