A fluidized bed furnace for roasting pyrite (sand) is prepared by taking acid residue or yellow sand as a fixed layer, blowing air into the air chamber of the fluidized bed furnace to make the fixed layer in a boiling state, directly adding granular sulfur into the fluidized bed under the condition of keeping the furnace temperature at 600-800 DEG C, igniting the sulfur under the action of heat and air to generate furnace gas containing SO2, cooling the furnace gas, purifying, drying, converting and absorbing. It is suitable for all devices that use crude pyrite (sand) to make acid, and can be directly converted into full-combustion solid sulfur without additional equipment, and the conversion from burning sulfur to burning pyrite (sand) is free and not limited by raw materials; When the unit burns sulfur completely, the oxygen content in the furnace gas increases due to the decrease of oxygen consumption, which increases the output of the original unit by 10- 15%. The sulfur consumption is 0.33t/t sulfuric acid (98%), which is not higher than that of sulfur-based sulphuric acid plant. Due to the complete combustion of sulfur, the production system basically has no dust emission, and the sewage has no precipitation emission. The sewage can be directly discharged after being neutralized by lime, and the environmental protection benefit is very obvious.
Pyrite is bound sulfur, which is not easy to be directly converted into elemental sulfur. It can be converted into sulfur dioxide first and then further reduced to obtain it. You can refer to the sulfuric acid industry. SO2 is generated first, and then reacts with H2S to generate sulfur.