Abstract A fine-grained concentrate of sulphide ore is suspended by a special dispenser into which a heated downward flow of air, air enriched with oxygen or oxygen containing gas in a vertical reaction shaft of a furnace to oxidize the non-oxidic metal compounds in the concentrate. The gases and the flue dust are separated from the solids which form a smelt on the bottom of the furnace consisting of a matte and a slag on the matte. The partial pressure of sulphur in the gases obtained from the oxidizing smelting carried out in the reaction shaft is increased and/or the partial pressure of oxygen is decreased, in which case the metal oxides contained in the flying dust are converted into corresponding sulphides and most of the iron contained in the slag retains the valence of 2.
An improved method as recited in claim 1, in which a fuel is dispersed into the gases emerging from the reaction shaft to decrease the partial pressure of the oxygen and reduce so much sulphur dioxide to sulphur that the partial pressure of the sulphur is at least as high as the dissociation pressure of the sulphur in the sulphur compounds of metals.
Claim 2
Dependent Claim
41 words
An improved method as recited in claim 1, in which the gases emerging from the reaction shaft are reduced to such an extent that the oxidic non-ferrous metal compounds contained in the slag are reduced into corresponding metals and metal sulphides.
Claim 3
Dependent Claim
44 words
An improved method as recited in claim 1, in which the gases emerging from the reaction shaft are reduced to such an extent that the oxidation of the ferrous oxide in the slag is prevented, formed Fe3O4 is reduced and the iron retains bivalent.
Claim 4
Dependent Claim
28 words
An improved method as recited in claim 1, in which the flying dust is separated from the gases after the furnace and used as fuel in flash smelting.
Claim 5
Dependent Claim
23 words
An improved method as recited in claim 1, in which the components of the flue dust are separated from each other by flotation.
Claim 6
Dependent Claim
43 words
An improved method as recited in claim 1, in which the gases emerging from the reaction shaft are reduced to such an extent that at least a part of the sulphur content of the gases is recovered in the form of elemental sulphur.
Claim 7
Dependent Claim
31 words
An improved method as recited in claim 1, in which the reduction of the gases emerging from the reaction shaft is regulated to adjust the SO2 content in the exhaust gases.
Claim 8
Dependent Claim
88 words
An improved method as recited in claim 1, in which the smelting in the reaction shaft is carried out in a strongly oxidizing manner so that a matte rich in metal is obtained and the reduction of the oxygen containing emerging from the reaction shaft is then carried out to such an extent that losses of metal from the matte into the slag are prevented from growing greater than with conventional metal contents in the matte, and thus the slag to be blown in a converter is decreased.