Process and apparatus for treating magnetic or weakly magnetic iron ore containing magnetic ferrous sulphide as a secondary constituent

摘要

159,380. St÷ren, R.., and Johanson, R. Dec. 18, 1919. Treating ores to facilitate concentration.-Magnetic iron ores containing pyrrhotite are heated in the presence of a reducing-gas to a temperature of 400-500‹ C., in order to render the ferrous - sulphide constituents permanently non-magnetic, and the product is subjected to magnetic concentration. Hydrogen obtained from an electrolytic decomposition plant is preferablv used. The ore traverses helical channels 2a, 2b in a rotary furnace in contact with the reducing-gas, which is supplied by a pipe 3 and escapes as water vapour through an opening 4. The partly reduced ore is suspended in water in a trough 5, and passes to a magnetic separator 6, and the concentrate is dried and completely reduced in a second furnace 8. The metal is finally melted in an electric &c. furnace directly connected with the furnace 8.