In 1889, Ludwig Mond discovered that the combustion of coal with air and steam produced ammonia along with an extra gas, which was named the Mond gas. He discovered this while looking for a process to form ammonium sulfate, which was useful in agriculture. The process involved reacting low-quality coal with superheated steam, which produced the Mond gas. The gas was then passed through dilute sulfuric acid spray, which ultimately removed the ammonia, forming ammonium sulfate.
Mond modified the gasification process by restricting the air supply and filling the air with steam, providing a low working temperature. This temperature was below ammonia's point of dissociation, maximizing the amount of ammonia that could be produced from the nitrogen, a product from superheating coal.