Arsenic leaching method from non-ferrous smelting ash

摘要

PROBLEM TO BE SOLVED: To provide a method for leaching arsenic from nonferrous smelting smoke ash capable of recovering almost all arsenic as a pentavalent arsenic solution without using a sulfidizing agent, and restraining copper from being mixed into the arsenic solution in recovering arsenic from nonferrous smelting smoke ash.SOLUTION: The method for leaching arsenic from nonferrous smelting smoke ash includes the steps of: slurrying the nonferrous smelting smoke ash, performing primary leaching by adding sulfuric acid to the slurry, performing oxidative leaching by adding an oxidizing agent to the slurry after adding water and/or a neutralizer to the slurry after the primary leaching step to adjust the pH, and performing secondary leaching for the obtained oxidative leaching residues and obtaining the arsenic solution for producing crystalline iron arsenate as a secondary leaching solution.