Within the framework of a joint Swedish-Soviet co-operative project, refining of impurities in steel has been studied. The work was split in two parts: 1) refining of copper from steel melts; and 2) phosphorus removal under reducing conditions with subsequent slag destruction. Refining of copper was carried out in the laboratory and in one pilot trial. The laboratory tests showed notable copper removal with sodium-based reagents, but the consumption of reagents is very high in addition to the necessity for an extra desulphurizing operation. A few lab-tests with soda-based (Na2CO3) reagents show promising results which could lead to a more economical procedure. Phosphorus removal under reducing conditions followed by destruction of the slag has been performed for 100 kg and in a pilot study. In the pilot study a method has been developed with controlled destruction of the slag in the ladle before removal of the phosphorus-containing slag. Including the destruction, the total dephosphorization reached 35%.