Improvements in the removal of arsenic and antimony from roasted sulphidic iron ores, especially roasted iron pyrites, and in the halogenation of the non-ferrous metals contained in these roasted ores

摘要

Roasted sulphidic iron ores containing antimony and arsenic are reacted at above 500 DEG C. with phosgene, a sulphur halogen compound (S2Cl2, SCl2), a sulphur oxyhalogen compound (SOCl2, SO2Cl2), with a sulphur fluorine compound corresponding to said sulphur chlorine compounds, with the thermal decomposition products thereof (CO and Cl2) or with substances which react together in the vapour phase to form said compounds (SO2 and halogen, sulphur vapour and halogen), all of these compounds or mixtures being diluted for use with such an amount of an inert gas that the iron in the ore remains substantially unattacked. The reaction may be performed in a multishelf, rotary or fluidized furnace. In the examples, a roasted iron pyrites ore containing arsenic, antimony, copper, lead and cobalt was reacted at 800 DEG C. in a rotary tubular furnace provided with shelves parallel to the axis, with sulphur chloride, sulphuryl chloride, thionyl fluoride and phosgene respectively, said gases being diluted in ratios between 1:5 up to 1:50 with nitrogen. The non-ferrous metals were present only in very small quantities after the product was leached with 4 per cent hydrochloric acid. Specification 749,078 is referred to.