Business Segments

Smelting and Refining

For the stable supply of nonferrous metals indispensable for the society

Business Overview

The smelting and refining business produces refined copper with purity of 99.99% or higher from copper concentrates having purity of around 30%. As byproducts of the copper smelting and refining processes, gold, silver and other precious metals, as well as sulfuric acid and other products are manufactured.
In Japan, these processes are carried out mainly by Pan Pacific Copper Co., Ltd. (PPC), a joint venture with Mitsui Mining & Smelting Co., Ltd. Its smelting and refining capacity is number one in Japan. We also have a comprehensive business partnership with LS-Nikko Copper in South Korea, a company in which we have a major share. PPC and LS-Nikko Copper together boast annual copper production capacity of approximately 920 thousand tons a year, among the highest in the world.
By ensuring safe and stable operation and pursuing efficiency, our Group aims to build up a production capability with world-rivaling cost competitiveness.


Refined copper

Copper cakes and billets

Gold (ingots and shots)

Silver (ingots and shots)

Sulfuric acid

Operating Sites

Business Processes

The Flow of Smelting and Refining Processes

1. Stockpile domes

The copper concentrates offloaded from ships are carried to stockpile domes, where they are stored separately by type. Multiple copper concentrates are mixed together and sent to a flash furnace.

2. Flash furnace process

The copper concentrates are blown into a flash furnace along with oxygen enriched air. An instantaneous oxidizing reaction inside the furnace causes the copper concentrates to melt by its combustion heat. After that, they are separated into copper matte with a grade of 65% and slag consisting of iron oxide, silicate and other components.

3. Converter furnace process

The matte produced from the flash furnace goes to a converter furnace. Oxygen enriched air is blown into the converter furnace and the matte is oxidized to become blister copper with a grade of approximately 99%.

4. Anode furnace process

In an anode furnace, butane gas is blown in as a reducing agent, removing the oxygen from the blister copper to raise the grade to 99.3%. The resulting blister copper is cast in anodes for use in electro-refining in a casting machine.

5. Electro-refining process

The cast anodes are alternated with stainless plates as cathodes in electrolysis cells filled with copper sulfate solution, and a direct current is introduced into the cells. The copper portion of the anodes is dissolved in the copper sulfate solution and deposits to the cathode plates. After about ten days of electrolysis, the cathode plates are pulled up from cells, the copper deposits is stripped from the plates, and is shipped as the final product of refined copper with copper grade of 99.99%.

Keywords for better understanding the smelting and refining business

Among the world's top class in production scale and competitiveness

Among the woBy actively pursuing smelting and refining alliances, our Group has maintained production capacity that is among the top globally. Taking advantage of these alliances, we are seeking to ensure safe and stable operations while boosting cost competitiveness.rld's top class in production scale and competitiveness

Worldwide trend in refined copper consumption

Against the background of economic growth by China and other emerging countries, worldwide consumption of refined copper is increasing year by year, which results in raising demands for stable supply of it.

Source: Wood Mackenzie Copper Market Service (Global copper long-term outlook Q1 2018)

Technology Development