Removal of arsenic from acids
AssigneeTenneco Canada Inc. (ERCO division)
InventorZbigniew Twardowski
Life of this patent
Estimating the term…
Abstract
Dissolved arsenic (III) contaminant is removed from mineral acids, such as hydrochloric acid, by electrolysis using a high surface area cathode having a three-dimensional electrolyte-contacting surface which exposes the electrolyte to electrolysis for a relatively long period of time. The dissolved arsenic is reduced to arsenic metal, which then plates out on the cathode. Dissolved concentrations of arsenic of less than 1 ppm can be achieved using the invention.
Claims16
A method for removal of dissolved arsenic (III) ions from hydrochloric acid, which comprises cathodically reducing the dissolved arsenic (III) ions to metallic arsenic in an electrolytic cell having a large surface area cathode with interstices through which said arsenic-contaminated hydrochloric acid flows during said cathodic reduction, said interstices defining a three-dimensional electrolyte-contacting surface, and depositing the arsenic metal so produced on said cathode.
A method for the removal of dissolved arsenic (III) ions from phosphoric acid, which comprises cathodically reducing the dissolved arsenic (III) ions to metallic arsenic in an electrolytic cell having a large surface area cathode with interstices through which said arsenic-contaminated phosphoric acid flows during said cathodic reduction, said interstices defining a three-dimensional electrolyte-contacting surface, and depositing the arsenic metal so produced on said cathode.
A method for the removal of dissolved arsenic (III) ions from a mineral acid, which comprises:
- chemically reducing any pentavalent arsenic ions present in the mineral acid to arsenic (III) ions,
- cathodically reducing the dissolved arsenic (III) ions to metallic arsenic in an electrolytic cell having a large surface area cathode having a three-dimensional electrolyte-contacting surface, and
- depositing the arsenic metal so produced on said cathode.
Dependencies are inferred from the claim text.