PT. Smelting applies Mitsubishi technology for copper smelting process. The Mitsubishi process is copper continuous smelting and converting technology using three furnaces. The three furnaces are linked with covered launders, through which all the molten materials are continuously transferred by gravity.

 

Copper concentrate (Cu:22-29 %, S: 27-32%, Fe: 22-27%) is fed through lance pipe with oxygen enriched air into the smelting furnace then oxidized and melted by exothermic reaction to form molten mixture of matte (Cu: 68%) and slag. The matte is separated from slag by difference of specific gravity in the slag cleaning furnace. The matte is further oxidized to form blister copper (Cu: 98.5%) in the converting furnace.