The invention provides a method for preparation of
sulfuric acid and combined production of fine flour iron through
calcination of
coal-derived
pyrite in presence of
oxygen-rich air, which belongs to the technical field of
resource utilization of
coal-containing
pyrite. The method comprises the following steps: delivering pretreated
coal-derived
pyrite and
oxygen-rich air into a
fluidized bed roaster for
calcination, carrying out cooling and dust collecting on high temperature furnace gas through a
water pipe, a
waste heat boiler and the like, carrying out cooling and demisting on furnace gasby using a one-stage dynawave
scrubber--a packed scrubbing column--a two-stage electric mist collector, supplementing a proper amount of common air before furnace gas enters into a
drying column, controlling the volume ratio of
oxygen to
sulfur dioxide in gas in a converter to be greater than 0.8, carrying out reforming and absorption two times after gas enters into a reforming and absorption
system, discharging
tail gas when the
tail gas reaches the standard, and recovering
heat energy of furnace gas,
slag and dust, furnace gas treated by an electric
dust collector, reforming gas of a reforming
system and
cyclic acid of an absorption
system for by-production of middle and low pressure steam. According to the invention, high-level and middle-level
heat energy produced in the process of production of
sulfuric acid is fully utilized, and the resource of dilute
sulfuric acid is recycled; therefore, the advantages of small production investment, low production cost, a high
recovery rate of
waste heat, clean production and no
pollution in production of sulfuric acid are realized.