The invention relates to the technical field of wet-process
phosphoric acid, in particular to a method for producing mixed-phase activated
gypsum by a wet-process
phosphoric acid process as well as a product and application thereof. The method comprises the following steps: adding ground
phosphate rock,
sulfuric acid, mixed acid and part of filtrate into an extraction tank, completing the extraction process, carrying out
solid-liquid separation on obtained mixed
slurry, feeding liquid as finished
phosphoric acid into an acid
library, and transferring
solid into a
crystal transformation tank; and adding
sulfuric acid, the filtrate and a
crystal form control agent into a
crystal transformation tank, carrying out
crystal transformation reaction at 80-105 DEG C for 2-10 hours to obtain mixed acid
slurry, carrying out
solid-liquid separation on the mixed acid
slurry, and washing the solid to obtain the mixed-phase excited
gypsum which is used for subsequent
gypsum products and
product processing or used as other raw materials. Filtrate enters a heat exchange
system to be heated and enters a
crystal transformation tank to be recycled, washing liquid reacts with concentrated
sulfuric acid to obtain high-temperature mixed acid, the high-temperature mixed acid enters the heat exchange
system to obtain low-temperature mixed acid, the low-temperature mixed acid enters an extraction tank to be recycled, and full utilization of chemical
heat energy is completed. The method is an improvement of a traditional wet-process phosphoric acid process, low-cost harmless treatment of the
phosphogypsum solid waste can be realized, in addition, high-temperature liquid-phase cooling and low-temperature liquid-phase heating are completed by fully utilizing concentrated sulfuric acid
dilution heat, and
energy conservation and emission reduction are realized.