The harmful elements in coal, including organic sulfur and inorganic sulfur, have a relatively broad requirement for sulfur in thermal coal, with coking coal requiring less than 1%. The sulfur in thermal coal has a serious corrosive effect on boilers, and the sulfur dioxide produced after combustion pollutes the atmosphere. The sulfur in coking coal is the main source of sulfur in furnace materials. High sulfur in coke leads to high sulfur in pig iron, high thermal brittleness, and reduced quality. In steelmaking pig iron, a sulfur content greater than 0.07% is considered waste. The synthesis of ammonia uses coal to produce semi water gas, and the hydrogen sulfide contained in the gas poisons and renders the catalyst ineffective.