REMOVAL AND STABILIZATION OF ARSENIC

摘要

The removal and stability of arsenic over a wide pH range (3.0-10.0) for synthetic solutions and industrial waste effluents (including mining waste tailing slurry) can be accomplished with addition of impure lanthanum chloride alone or in conjunction with ferric sulfate. The long term stability of these corresponding precipitated compounds is critical from the disposal standpoint. In this paper test results of this new process for arsenic removal and stabilization from the above mentioned systems are presented. Also, precipitated arsenic compounds (lanthanum arsenate, lanthanum-ferric arsenate, ferric-lanthanum arsenate and ferric arsenate) from synthetic solutions have been characterized. The characterization technique used was XRD. XRD patterns which shows that the lanthanum arsenate and lanthanum-ferric arsenate formed in acidic and alkaline pH at room temperature are crystalline. On the contrary, ferric arsenate and ferric-lanthanum arsenate compounds formed under the same conditions as lanthanum arsenate were amorphous.