METHOD AND SYSTEM FOR DECONTAMINATING SAND

1 . A method for treating contaminated sand from a production waste pit, the method comprising:

pre-treating the contaminated sand to remove one or more non-radioactive materials;

washing the contaminated sand with a dissolver solution and water to remove naturally occurring radioactive material from the sand;

recovering the dissolver solution from the sand; and

collecting the treated sand.

2 . The method of claim 1 , further comprising regenerating the dissolver solution.

3 . The method of claim 2 , wherein regenerating the dissolver solution further comprises:

pumping dissolver solution into a dissolver regeneration vessel;

dosing acid into the dissolver regeneration vessel;

precipitating naturally occurring radioactive material and other solids from the dissolver solution;

removing brine from the dissolver regeneration vessel; and

pumping fresh water and a base into the dissolver regeneration vessel to reconstitute the dissolver solution.

4 . The method of claim 1 wherein the pre-treating step further comprises:

directing the contaminated sand into a feed hopper;

heating water;

directing a portion of the heated water into the feed hopper;

slurrying the water and the contaminated sand in the hopper;

directing the slurry to a hydrocyclone; and

directing an underflow of the hydrocyclone to an Elutriation column to remove hydrocarbon from the sand.

5 . The method of claim 4 , wherein the heating water step further comprises heating the water to approximately 80 degrees C.

6 . The method of claim 4 , wherein the pre-treatment step further comprises:

treating the sand from the Elutriation column with acid to dissolve any calcium carbonate.

7 . The method of claim 1 , wherein washing the contaminated sand further comprises:

directing cleaned sand from the pre-treating step to a dissolution reactor;

heating a dissolver chemical;

pumping the dissolver chemical into the dissolution reactor;

reacting the dissolver chemical and the sand;

separating the sand from a liquid component including spent dissolver fluid.

8 . The method of claim 7 wherein the ratio of dissolver chemical to sand is 2:1.

9 . The method of claim 1 wherein the step of pre-treating the contaminated sand comprises contacting the contaminated sand with an acid solution to dissolve calcium carbonate.

10 . The method of claim 1 wherein the step of pre-treating the contaminated sand comprises:

heating the contaminated sand to convert calcium carbonate to calcium oxide;

contacting the heat-treated sand with water; and

separating the heat-treated sand from the water.

11 . The method of claim 1 further comprising the step of:

treating waste water to remove contaminates.

12 . The method of claim 1 wherein the dissolver solution comprises a chelating agent.

13 . The method of claim 4 , wherein the pre-treatment step further comprises:

heating the sand from the Elutriation column to convert calcium carbonate to calcium oxide;

contacting the heat-treated sand with water; and

separating the heat-treated sand from the water.

14 . A system for treating contaminated sand from a production waste pit, the system comprising:

a hopper within which the contaminated sand and heated water are slurried;

a hydrocyclone receiving the slurried sand, the hydrocyclone separating the sand from a water component;

an Elutriation column receiving sand from the hydrocyclone, the Elutriation column removing hydrocarbon from the sand;

a calcium carbonate removal stage receiving the sand from the Elutriation column;

a reactor receiving the sand from the calcium carbonate removal system, wherein the sand and a dissolver solution are reacted within the reactor to remove naturally occurring radioactive material from the sand;

a dissolver regeneration vessel within which the spent dissolver solution from the reactor and a brine are mixed;

a dosing pump for adding acid to the dissolver regeneration vessel; and

a dosing pump for adding base to the dissolver regeneration vessel.

15 . The system of claim 14 wherein the calcium carbonate removal stage comprises a vessel in which an acid contacts the sand.

16 . The system of claim 14 wherein the calcium carbonate removal stage comprises: a furnace in which the sand is heat-treated;

a washing stage in which the heat-treated sand is contacted with water; and

a separator in which the heat-treated sand is separated from the water.

17 . The system of claim 14 further comprising a separation tank for treating waste water from the hydrocyclone and dissolver regeneration vessel.