Patent ID: 7955409

Claim:
A method of smelting copper comprising: a generating step of generating blister and a calcium ferrite slag from copper matte by charging the copper matte into a smelting furnace and oxidizing the copper matte, wherein a calcium oxide concentration in the calcium ferrite slag is from 10 weight % to 20 weight %, and a copper grade of the calcium ferrite slag is from 15 weight % to 25 weight %; a first refining step of heating the calcium ferrite slag by providing electrical power to the calcium ferrite slag from an electrode in a resistance heating electrical furnace and refining another blister from the calcium ferrite slag by reduction in the resistance heating electrical furnace; and a charging step of charging a slag generated in the first refining step into one of the smelting furnace or another smelting furnace for treating copper concentrate and generating matte as repeating flux if a copper grade of the slag generated in the first refining step is higher than 0.8 weight %.