Metallurgical process using oxygen

A continuous process for recovering metal values from non-ferrous metal sulfide concentrates wherein a molten bath comprising a metal-rich phase and a slag phase is established and maintained beneath a sulfur dioxide-containing gaseous phase, in an elongated tiltable refractory-lined sealed furnace into which concentrates, flux and an oxidizing gas are introduced while value metal-rich material, slag and off-gases are separately removed, and wherein prior to removal from said furnace the slag is subjected to a cleaning treatment to reduce the value metal content thereof, characterized in that

• a. the concentrates treated are selected from the group consisting of copper, nickel, cobalt and lead and combinations thereof;
• b. the metal-rich and slag phases are withdrawn from opposite ends of the furnace whereby said phases are caused to flow countercurrent to each other throughout in substantially continuous lineate streams toward their respective outlets;
• c. oxygen is introduced in gas concentrations and amounts effective to render the process autogenous;
• d. at least a substantial portion of the oxygen introduced is blown upwardly into the molten bath, through several independently regulated subsurface injectors distributed lengthwise of said furnace along a substantial portion of the molten bath;
• e. the solid feed materials are introduced stagewise into said furnace through several independently regulated feeders distributed lengthwise of said furnace along a substantial portion of the molten bath;
• f. the sites and rates of introduction of oxygen and solid feed materials are located and regulated to provide a gradient of oxygen activity in the molten bath decreasing progessively and sequentially from a maximum effective for producing value metal-rich material of low iron content at its outlet to a minimum effective for producing slag of low value metal content at its outlet;
• g. protective fluid is introduced through the subsurface injectors with the oxygen in regulated amounts effective for protecting the injectors and surrounding refractories and for aiding process temperature control;
• and
• h. the subsurface combined gas injection rates are controlled to provide a minimal degree of bath turbulence effective for intimate interphase contact of reactants without substantial interruption of said lineate stream flow and oxygen activity gradient.