METHOD FOR RECYCLING FERROUS SULFATE HEPTAHYDRATE AND SULFURIC ACID FROM WASTE ACID IN TITANIUM DIOXIDE PRODUCTION

• Main Authors: MA, Mingjian, GUO, Hongdan, XU, Tianlong, JIANG, Ge, LIU, Hongjin
• Format: Patent
• Language: English
• Published: 26.06.2024

The present disclosure provides a method for recycling ferrous sulfate heptahydrate and sulfuric acid from a waste acid in titanium dioxide production, including the following steps: step 1: pre-concentrating the waste acid in titanium dioxide production to obtain a pre-concentrated acid; step 2: cooling the pre-concentrated acid by a heat exchanger, and conducting freezing crystallization for a period of time to obtain the ferrous sulfate heptahydrate and a crystallization mother liquor; step 3: concentrating the crystallization mother liquor in a waste acid evaporation system to obtain precipitated miscellaneous salt-containing suspended concentrated acid and evaporation condensed water; and step 4: subjecting the precipitated miscellaneous salt-containing suspended concentrated acid to maturing and cooling, and then transferring a resulting product into a filter press dehydration system to allow a treatment to obtain a metal miscellaneous salt filter cake and a filtered finished acid.