The invention relates to a method for controlling suspension (8) in a suspension smelting furnace (1), to a suspension smelting furnace, and to a concentrate burner (2). The method comprises feeding additionally to pulverous solid matter (6) and additionally to reaction gas (7) reducing agent (13) into the suspension smelting furnace (1), wherein reducing agent (13) is fed in the form of a concentrated stream of reducing agent (13) through the suspension (8) in the reaction shaft (2) onto the surface (9) of the melt (10) to form a reducing zone (15) containing reducing agent (13) within the collection zone (14) of the melt (10).

The present invention provides a method of converting copper containing material to blister copper comprising: (a) providing copper containing material comprising copper sulfides and iron sulfides, whereby the copper containing material comprises at least 35 wt % copper of the total weight of the copper containing material; (b) reacting the copper containing material in a furnace with an oxygen containing gas, in the absence of flux, to effect oxidation of iron sulfide and copper sulfide, and controlling injection of the oxygen containing gas and the temperature so that the resulting converter slag is in a molten phase to obtain blister copper and converter slag.

Disclosed herein are methods for obtaining a composition including copper sulfide from a material, where the methods include: contacting the material with an acidic aqueous solution having a pH less than 6 in the presence of sulfur dioxide to form copper sulfide; where the material includes one or more copper compounds chosen from copper in a zero oxidation state, copper oxide, and copper hydroxide, and where the material includes an amount of zero oxidation state metals having a standard redox-potential less than zero volt versus a standard hydrogen electrode. Also disclosed are methods for recycling at least one battery material, and compositions including copper sulfide.