Complex sentence: Ruthenium is found to be a catalyst in a very important new industrial process, but very little of the metal is known to remain on Earth, and the search for a new deposit in Canada is a vital part of the plot.
Split into simpler sentences: Ruthenium is found to be a catalyst in a very important new industrial process. But very little of the metal is known to remain on Earth, and the search for a new deposit in Canada is a vital part of the plot.