Illustrator Ryoko Takagi visits Sumitomo Group
Sumitomo Metal Mining Niihama Nickel Refinery

Niihama, Ehime Prefecture, is home to Japan’s sole refinery for
production of high-purity electrolytic nickel and electrolytic cobalt.

Sumitomo Metal Mining Niihama Nickel Refinery
  • Sumitomo Metal Mining Niihama Nickel Refinery
Mixed Sulfide

Mixed sulfide is the raw material from which electrolytic nickel and electrolytic cobalt are obtained. This sand-like stuff containing about 60% nickel by weight is produced by subsidiaries in the Philippines.

It’s a maze !

Arriving at the plant, I am confronted by a bewildering array of piping running in all directions. Such a scene is typical of the big industrial plants I have visited on other trips. But as I make my way into the heart of the site, entering a cavernous building where they produce electrolytic nickel—that’s high-purity nickel produced by electrolysis, it dawns on me that something is missing. “There is hardly any noise!” This calm atmosphere is a world away from metal-bashing plants where assembly, pressing, and other processes kick up a tremendous noise and lots of vibration.

Even before I set foot in the plant, the very name Sumitomo Metal Mining led me to expect giant draglines, conveyors, ore crushers, belching chimneys and ever-present harsh, jarring noise. I couldn’t have been more wrong. This place is “So quiet!” Apparently it’s because the MCLE method used to produce electrolytic nickel is as quiet as a mouse, all chemistry and no metal bashing!

The MCLE method—short for Matte Chlorine Leach Electrowinning, goes like this. First, nickel contained in mixed sulfide(MS) intermediate, which is a kind of halfway house between unprocessed ore and refined nickel, is dissolved using chlorine. Next, an anode and a cathode are inserted in the solution. Then current is applied to perform electrolysis. Abracadabra! Nickel is electrodeposited on the cathode! Ions are the unsung heroes of electrolytic nickel production. They work quietly and diligently to recover the nickel. So there is no burning or banging!

The great advantage of MCLE is its efficiency in producing high-purity electrolytic nickel. Another merit is that it doesn’t involve the use of heat. On the other hand, MCLE does involve risks associated with chemical reactions. Chlorine and various chemical solutions must be strictly managed.

While listening to the explanation, I gazed at an electrolytic cell containing solution. “People are working with dedication and discipline. But no one works as hard as the ions in the solution. They never take a break!” I wanted to say a word of appreciation to them. “Ions, you are doing a great job performing electrolysis all day long!”

工場内
In an electrolytic cell, nickel is electrodeposited on stripping plates, which are thin nickel plates. When deposition reaches a thickness of about 1 centimeter, these plates are hoisted out and the nickel is recovered.
Suited up in protective gear for safety during the plant tour
Nickel is used in lots of different things
jet engines, stainless pots and pans, 500-yen coin

Applications of nickel

Nickel is a vital ingredient of products that vary greatly in shape, size and purpose. They range from the humdrum stainless pots and pans in your kitchen and even the 500-yen coin in your pocket to the sophisticated battery materials for hybrid vehicles and electric vehicles, as well as corrosion- and heat-resistant alloys found in jet engines.

So many chemical symbols in the plant!

Raw materials flow through these pipes!
In the plant, I saw a board stating... Hydrochloric acid!
Here are some chemical symbols.
It’s like taking a science quiz back in junior high school!
Electrolytic nickel products.
Electrolytic nickel products.
Nickel sulfate is suitable for plating and battery materials.
Nickel sulfate is suitable for plating and battery materials.
Nickel hydroxide is the cathode active material for nickel hydride batteries in hybrid vehicles.
Nickel hydroxide is the cathode active material for nickel hydride batteries in hybrid vehicles.
Lithium nickel oxide is the cathode material for lithium-ion batteries whose principal application is electric vehicles.
Lithium nickel oxide is the cathode material for lithium-ion batteries whose principal application is electric vehicles.

Immerse yourself in Sumitomo Group’s history
at Besshi Copper Mine Memorial Museum
Immerse yourself in Sumitomo Group’s history at Besshi Copper Mine Memorial Museum

Besshi Copper Mine Memorial Museum
Besshi Copper Mine Memorial Museum has six corners.
The ruins of Tonaru ore storage depot and mill
The ruins of Tonaru ore storage depot and mill, sometimes known as “the Machu Pichu of the Orient”

What an idyllic spot! Arriving at Besshi Copper Mine Memorial Museum, I took a deep breath, filling my lungs with wonderfully fresh morning air and gazed at the forest-clad mountains. I couldn’t imagine that copper had been mined from those mountains.

One of the highlights is a fascinating model of the Besshi Copper Mines and their vicinity in the late 19th century during the heyday of Japan’s Meiji-era industrialization. This was a real community with an elementary school, a hospital, a theater, and other communal facilities around the mines. Miners, engineers, and others associated with the mines and their families lived in a virtually self-contained community. The hospital established in those days still flourishes as a medical clinic affiliated with Sumitomo. This was a Sumitomo town!

Besshi Copper Mine Memorial Museum is a chance to immerse yourself in Sumitomo’s history, including the many technical and regulatory obstacles Sumitomo had to overcome after the discovery of the copper deposit in order to establish the mines as a going concern that became the jewel in the Sumitomo crown. Time and again, Sumitomo was able to rise to the challenge, thanks to a workforce and a leadership selflessly devoted to the success of this ambitious enterprise.
The Besshi Copper Mines are at the heart of the Sumitomo Group and its upward trajectory from the late 19th century onward. Here at the Besshi Copper Mine Museum, Sumitomo’s business philosophy that continues to this day and the aspirations of the people who worked at the mines are palpable. Although the mines are vividly recreated in the museum, they are receding into history. The mountains have returned to nature thanks to afforestation, their service as a source of copper ore a memory. But they remain an imposing yet protective presence for the people living in the area.

gallery of the Besshi Copper Mines

In a gallery of the Besshi Copper Mines, workers hand-pumped water issuing from springs deep underground. Each team would pump away for three hours before being replaced by the next one, and so eight teams would cover the 24-hour cycle. (Photo courtesy of Sumitomo Historical Archives)

「Hard work! It must have been a tough three hours!

Editor’s note

Besshi Copper Mine Memorial Museum
Besshi Copper Mine Memorial Museum amid satsuki azaleas
Ms. Takagi with raw materials that have just been delivered to the Niihama Nickel Refinery
Ms. Takagi with raw materials that have just been delivered to Niihama Nickel Refinery

I had imagined that any industrial plant would be incredibly noisy. So the quietness of Niihama Nickel Refinery we visited this time came as a great surprise to me and, indeed, to all of us.


Only in the building where electrodeposition is performed did we encounter an exception to this general quietness. While stripping plates were being hoisted and transported from the electrolytic cells to the nickel recovery site, a peculiarly cheerful electronic sound rang out—something totally different from what you would expect to hear in a factory—to alert people in the vicinity. Relishing the experience, Ms. Takagi exclaimed, “It’s like a giant claw crane in a gigantic amusement arcade!”


We also visited the Besshi Copper Mine Memorial Museum, a short drive from the plant. Some 10,000 satsuki azaleas adorn its rooftop garden: an inspired choice since satsuki also means May in Japanese, the very month in which the Besshi Copper Mines received a license to operate and these glorious plants come into bloom.


When we visited, the satsuki azaleas had just started to bloom and a delicate fragrance filled the air. It is a popular spot for photographers and there were quite a few people with cameras capturing the magnificent floral show. I took a few snaps with my smartphone.

Number(Illustrator Ryoko Takagi visits Sumitomo Group)

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