Process for removing arsenic from soil
AssigneeTexas Romec, Inc.
InventorsMark A. O'Connor, Rodney J. O'Connor
Life of this patent
Estimating the term…
Abstract
An invention for removing arsenic from contaminated soil is described. The process of this invention involves contacting contaminated soil with a carbonated solution either formed by bubbling carbon dioxide through water or dissolving in alkali metal carbonate in water for contact of the contaminated soil. The supernatent solution resulting can then be treated to remove the arsenic, preferably with reverse osmosis, for further use of the water and the decontaminated soil returned to the environment.
Claims17
A method for treating soil contaminated with arsenic which comprises the steps of
- a. contacting the contaminates soil with a carbinated aqueous solution for a time sufficient to leach arsenic from the soil into the aqueous solution;
- b. separating the leached soil from the aqueous solution containing the leached arsenic.
A method for removing arsenic from contaminated soil which comprises the steps of:
- a. sizing the soil to pass through a screen of about a 40 mesh size;
- b. slurrying the sized soil to a level of from about 10% to about 50% solids by weight with a carbonated aqueous solution formed by introducing gaseous carbon dioxide into the soil slurry to contact the arsenic contaminated soil at a pressure of from about 15 psi to about 1,000 psi for a time sufficient to react with arsenic present in the soils;
- c. separating the soil from the solution;
- d. slurrying the soil with an alkali metal carbonate solution containing from about 1% to about 10% by weight alkali metal carbonate based upon the amount of water used to form the slurry having from about 10% to about 50% by weight solids content for a time sufficient to react with arsenic present in the soil;
- and
- e. separating the soil from the water.
A method for removing arsenic from contaminated soil which comprises the steps of:
- a. sizing the soil to pass through a screen of about a 40 mesh size to separate particles of gravel from soil;
- b. slurrying the sized soil to a level of from about 10% to about 50% solids by weight with a carbonated aqueous solution formed by introducing gaseous carbon dioxide into the soil slurry to contact the arsenic contaminated soil at a pressure of from about 250 psi to about 500 psi for a time sufficient to react with arsenic present in the soils;
- c. filtering the soil from the solution;
- d. repeating steps b. and c. two times to partially decomtaminate the soil;
- e. contacting, with stirring, the partially decontaminated soil with a sodium carbonate aqueous solution containing from about 3% to about 8% by weight sodium carbonate based upon the amount of water used to form the slurry having from about 30% to about 45% by weight solids content for a time sufficient to react with arsenic present in the soil;
- f. separating the soil from the water;
- g. repeating steps e. and f. and recovering dewatered soil;
- and
- h. disposing of the dewatered soil to meet applicable regulatory criteria.
Dependencies are inferred from the claim text.