The invention belongs to the technical field of
solid waste recycling and
wastewater treatment, and particularly relates to a method for treating
chromium-containing
wastewater by adopting organic amine
flue gas desulfurization residues. According to the method, organic amine
flue gas desulfurization residues are used as a
reducing agent,
phosphoric acid is used for controlling the pH value of
wastewater,
hexavalent chromium is reduced into trivalent
chromium under the acidic condition, meanwhile, desulfurization ash is converted into a
melamine phosphate flame-retardant material, and trivalent
chromium is separated from water in a
precipitation form under the neutral condition; after the precipitate is roasted,
chromium sesquioxide powder with relatively high purity is obtained, residual
ammonia nitrogen in the wastewater, the added
magnesium salt and residual
phosphoric acid in the water form
struvite precipitate, so that the
ammonia nitrogen in the water is removed, and the
struvite can be used as a
raw material of a slow-release
fertilizer. According to the method, the treatment cost of the
vanadium extraction wastewater and the
flue gas desulfurization
slag is remarkably reduced, valuable elements are fully recycled, and
resource utilization of
flue gas desulfurization waste in a waste-to-waste mode is achieved.