PROCESS FOR STABILIZATION OF ARSENIC

摘要

The present invention is a method to remove arsenic from arsenic-containing materials (10) which is roasted (14) to form an offgas (18) and a roasted arsenic-containing material (22). An oxygen containing gas (26) is contacted with the arsenic-containing material. The offgas is subjected to solids collection (30) to form solids (34) and an offgas (38) for scrubbing (42). The solids (34) are combined with the roasted arsenic-containing material (22) before solubilization (46). The offgas (38) is subjected to scrubbing (42) with a scrubbing solution (50) to form a scrubbed offgas (58). The scrubbing solution is a portion of a pregnant leach solution (54). The scrubbed offgas is treated to remove sulfur dioxide (62). During solubilization arsenic oxides, ferric sulfates and ferric arsenates are dissolved to form a product slurry (62). The product slurry is subjected to liquid/solid separation (66) to form a leach residue (70) and a pregnant leach solution (54). A portion of a treated solution (74) is combined with water (118) to form a wash solution (78). The wash solution is used during liquid/solid phase separation to wash the leach residue to remove arsenic.