Power Magazine, Mar. 2014, by Gail Reitenbach, PhD.
http://www.powermag.com/converting-sulfur-from-flue-gas-into-fertilizer/

"As environmental regulations tighten—both in the U.S. and around the world—coal-fired power plants continue to look for ways to operate economically. Though reuse and sale of coal combustion by-products has a long history, one new approach could benefit a somewhat unlikely partner industry."