The invention relates to a
high concentration phosphoric acid producing method by directly deoxidized
phosphorite. The process that the stock produced by
phosphorus ore, diatomite,
coke or
coal accomplishes a reduction-oxidation to produce
phosphoric acid consists of a preheating zone, a reducing zone and an oxidation
combustion zone which are composed of different equipment modules. The preheating zone is under 1150 DEG C to 1200 DEG C; the reducing zone is under 1250 DEG C to 1450 DEG C, the
coke or the
coal in the stock performs a reduction reaction with
phosphorite;
phosphorus vapor that is P4 and
carbon monoxide gas which are produced enter into the oxidation
combustion zone again; air is added into the oxidation
combustion zone, thus the
phosphorus vapor that is P4 and the
carbon monoxide gas are oxidized to produce a mixed
kiln gas which is composed of P2O5 and CO2; the mixed
kiln gas with high temperature is sucked out and led into a hydration absorption
tower after
dust abatement, and the
phosphoric acid is produced by recycle acid absorption. The stock after the reduction reaction is exported from the reducing zone, and is formed into
cement clinker or building materials after cooling and
heat transfer. The invention has the innovative points that the processes of preheating, deoxidizing and oxidizing of reducing gas of the stock are separated, and the reactions are not mutually interfered. The control of the action process is simple, in addition, the percent reduction of the
phosphorite is high, and the high yield of
total phosphorus can be gained.