The invention provides a process for removing F, Cl and As from waste acid by a hot
air concentration method.
Flue gas generated in the process of
smelting non-
ferrous metal is subjected to electrical dust
precipitation and is used for making acid, and F, Cl and As are contained in
dilute acid. The removal process comprises the following steps of: 1) blowing air into a SO3 cooler by using a blower, converting the air into hot air by using a large amount of
waste heat released in the process of converting SO2 into SO3, and allowing the hot air to enter the bottom of a concentration
tower; 2) pumping the waste acid to the top of the concentration
tower by using a waste acid delivery pump, spraying the waste acid from the top of the
tower, and allowing the waste acid to fully contact the hot air from bottom to top; 3) making the F and the Cl in the waste acid combined with
water vapor and enter a
tail gas washing tower 4 in an acid mist form, and pumping alkaline liquor in an alkaline liquor
storage tank into the
tail gas washing tower by using an alkaline liquor delivery pump, and neutralizing to obtain salt for emission; and 4) cooling concentrated
sulfuric acid obtained at the bottom of the concentration tower to remove the As, and performing
vulcanization impurity removal to obtain an industrial product such as
sulfuric acid. The process has the advantages of small occupied area, short flow, high waste
acid treatment capacity and the like.