METALLIC NICKEL, PURE NICKEL AND SUDBURY'S BIG NICKEL
Like many discoveries, Mond’s breakthrough came about in a roundabout fashion
The largest coin in the world is a 1951 Canadian nickel. But you can't put this one in your pocket: it's about 30 feet high and two feet wide. The Big Nickel, a popular tourist attraction in Sudbury, Ont., commemorates the 200th anniversary of the isolation of metallic nickel by Swedish mineralogist and chemist Baron Axel Frederic Cronstedt and indirectly also pays homage to the ingenuity of another chemist, Ludwig Mond, who developed the first commercial process to produce pure nickel. The Sudbury area is rich in nickel-bearing ore and has a long history of supplying the metal to the world, a process in which Mond also played a large part.
Back in the 17th century, German miners searching for copper discovered a reddish ore that looked to be a source of the metal. However, try as they might, they were unable to extract any copper and concluded that a prank had been played on them by Nickel, a mischievous demon in German mythology. They named the ore that would not yield copper “kupfernickel,” meaning “copper demon.” It didn't yield copper for the simple reason that it didn't contain any, as was eventually shown by Cronstedt, who in 1751 heated kupfernickel with charcoal and produced a metal not seen before that clearly was not copper. He dropped the term “kupfer” and named the metal “nickel.” Cronstedt had discovered a new element!
Nickel is shiny, sturdy and resists corrosion, which made it ideal for use in coins and stainless steel. Armour on ships previously made of iron was greatly strengthened when the iron was alloyed with nickel. Producing pure nickel from its ore, however, was a challenge, one that eventually was met by Ludwig Mond, who certainly did not set out to purify nickel. Like many discoveries, this one came about in a roundabout fashion.
Mond was born in 1839 to a prominent Jewish family in Germany. His father was able to send him to the best schools, including the University of Heidelberg where he studied under Robert Bunsen of burner fame. He left before completing his doctorate, apparently more interested in practical than theoretical chemistry. Young Mond found a job with a factory producing acetic acid by the distillation of wood, where he found an economical way to combine acetic acid with copper to produce verdigris, a much sought-after green pigment. The next step in the chemist's career was taken at a Leblanc soda works factory that produced sodium carbonate, often abbreviated as “soda.” a key chemical in making paper and glass. One problem was the large amounts of a waste product, calcium sulphide, that was produced along with the soda. Mond managed to develop a process to convert the calcium sulphide into marketable sulphur. This brought him to the attention of the John Hutchinson Company, an English soda manufacturer, and prompted a move to England in 1862. He went to work for the company, but soon decided to set out on his own with partner John Brunner.
The major competitor of the Leblanc process was the “ammonia-soda” process developed by Belgian chemist Ernest Solvay.
Not only was this more efficient, but Mond believed that the waste it produced, ammonium chloride, could be profitably converted into chlorine gas. He travelled to Belgium where he convinced Solvay to license Brunner, Mond and Company to produce sodium carbonate by his method. It was during the conversion of the ammonium chloride to chlorine that Mond made the discovery that would launch him into the next step of his career, the production of nickel.
The production of chlorine involved vaporizing ammonium chloride and passing it through a network of pipes and valves. Nickel, because of its resistance to corrosion, was used to construct the valves. While the process worked well, the valves tended to leak as they became coated with a mysterious black deposit. Mond, intrigued, studied this deposit and found to his amazement that with heat it turned it into shiny, metallic nickel! Further analysis revealed that the deposit was nickel carbonyl, formed by the reaction of nickel with carbon monoxide. But where did the carbon monoxide come from? It turned out that the pipes were periodically flushed with carbon dioxide to blow out residual vapours of ammonia and the carbon dioxide was contaminated with traces of carbon monoxide.
While some may have just concentrated on fixing the problem by eliminating the carbon monoxide, Mond realized that he had made an important discovery. He had produced extremely pure nickel! Exploiting this serendipitous discovery, he founded the Mond Nickel Company and purchased nickel ore mines around Sudbury. Here the ore was smelted and impure nickel shipped to a refinery in Wales where it was be treated with carbon monoxide to yield the nickel carbonyl that would then be heated to produce pure nickel.
Mond's soda, and then his nickel business made him into a wealthy man. He was generous to his employees, being one of the first industrialists to offer paid vacations, eight-hour workdays and fringe benefits such as recreation clubs and sports fields. A great promoter of chemical research, he donated large sums to Britain's Royal Institution, the Children's Hospital of London and to his alma mater, the University of Heidelberg. Mond was also an enthusiastic supporter of the arts and donated a his sizable collection of Italian Renaissance paintings to the National Gallery in London, the largest single gift the museum has ever received.
While the 1951 coin on which the Big Nickel was modelled was made of 99.9 per cent nickel, the giant sculpture is made of stainless steel, which of course does contain some nickel. And those nickels in your pocket now? Made of steel and copper with a thin plating of nickel. Just enough to now make you think of the contributions of Ludwig Mold to science, the arts and social reform.