Process for disposal of arsenic salts
AssigneeWaste Management of Illinois, Inc.
InventorMahendra D. Sandesara
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Abstract
Arsenic-containing waste materials comprising water-soluble arsenic salts are processed to a product which comprises water-insoluble arsenic salts by reacting the same in an aqueous system with sulfuric acid and calcium hydroxide in the presence of sulfate ions and ferrous and/or ferric ions, and thereafter curing the system to solid form. The process can be practiced with conventional waste materials without preliminary special processing, and provides a product which can be easily handled and is amenable to secure landfill disposal.
Claims20
A process for converting a waste material containing water-soluble arsenic salts to a waste material containing water-insoluble arsenic salts which comprises mixing an aqueous system comprising said water-soluble arsenic salts, sulfuric acid and calcium hydroxide in the presence of sufficient ferrous ions to ensure proper curing of the aqueous system to solid form, and sufficient iron in the aqueous system, either in ferrous and/or ferric form, to react with arsenic derived from the water-soluble arsenic salts present, whereby the aqueous system is formed into a slurry, the slurry being contacted with an oxygen containing gas to oxidize the slurry due to contact of the slurry with the oxygen, thus causing the entire slurry to cure to solid form.
Dependencies are inferred from the claim text.