Manufacturing method of crude copper from low-grade copper sludge

A manufacturing method of crude copper from low-grade copper sludge, comprising the steps of:

• calcining a low-grade copper sludge which comprises iron (step 1);
• producing a mixture by adding a binder and optionally a first flux to the calcined low-grade copper sludge (step 2);
• producing a briquette by compression molding the mixture (step 3);
• melting and reducing by charging the briquette into a submerged arc furnace with adding second flux which comprises silica and calcium oxide (step 4);
• and
• separating crude copper and slag produced by the melting and reducing (step 5),
• wherein the second flux is added in step 4 so as to form a slag comprising:
• iron oxide (FeO) in a range of 40 wt % to 57 wt %;
• silica (SiO2) in a range of 33 wt % to 37 wt %;
• and
• calcium oxide (CaO) in a range of 10 wt % to 23 wt %, and
• the binder in step 2 comprising bentonite.