Arsenic fixation method

The invention discloses an arsenic fixation method which comprises the following steps: (1) pretreatment of arsenic-containing waste residues: crushing arsenic-containing waste residues to the particle size of less than 0.5cm, and drying at low temperature until the water content is lower than 5%; (2) iron-base arsenic fixation reaction: proportionally mixing the pretreated arsenic-containing waste residues with thermit and iron-base curing agent, adding into a ball mill, and carrying out arsenic fixation reaction to obtain the iron-base arsenic fixation product; and (3) calcium-base reinforcement reaction: adding a calcium-base reinforcer into the iron-base arsenic fixation product, and continuing the reinforcement reaction in the ball mill to obtain the end arsenic fixation product. The method has the advantages of high arsenic fixation ratio, short time consumption, simple technique, no secondary pollution and the like, is easy to operate, and can be used for stabilization and innocent treatment of arsenic-containing waste residues. The invention not only can be combined with the traditional techniques of lime solidification, cement solidification and the like to enhance the arsenic fixation effect, but also can be directly used for final treatment of arsenic-containing waste residues.