Method and apparatus for cleaning contaminated particulate material
First Claim
1. A method for removing contaminants comprising heavy metals and radioactive compounds, singly and in combination, from a process stream used in removing said contaminants from contaminated particulate material, said method including the steps of:
- washing said contaminated particulate material with said process stream, thereby removing said contaminants from said particulate material, said process stream containing an oxidizing agent selected from the group Cl2, ClO2 and O3 and/or a reducing agent, said oxidizing or reducing agent rendering at least one of said contaminants more soluble in said process stream;
separating clean particulate material from said process stream;
treating said process stream with a precipitant to remove said contaminant rendered more soluble in said process stream by said oxidizing or reducing agent; and
recycling said process stream for washing additional contaminated particulate material.
17 Assignments
0 Petitions
Accused Products
Abstract
Particulate material is treated by first washing the contaminated material with a contaminant mobilizing solution comprising a leaching agent, a surfactant or a mixture thereof. Large particles, typically greater than 5 mm are mechanically separated, washed with water and returned to the site as recovered soil. Fines, along with contaminants dissolved or dispersed in the contaminant mobilizing solution are separated from intermediate sized particles by a countercurrent flow of the contaminant mobilizing solution, preferably in a mineral jig. The intermediate sized particles are then abraded in an attrition scrubber to dislodge attached mineral slimes or fines. These additional fines are separated from the intermediate sized particles with a countercurrent flow of wash water in a second mineral jig. The preferred oxidizing agent is chlorine, and hydrogen is the preferred reducing agent.
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Citations
35 Claims
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1. A method for removing contaminants comprising heavy metals and radioactive compounds, singly and in combination, from a process stream used in removing said contaminants from contaminated particulate material, said method including the steps of:
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washing said contaminated particulate material with said process stream, thereby removing said contaminants from said particulate material, said process stream containing an oxidizing agent selected from the group Cl2, ClO2 and O3 and/or a reducing agent, said oxidizing or reducing agent rendering at least one of said contaminants more soluble in said process stream; separating clean particulate material from said process stream; treating said process stream with a precipitant to remove said contaminant rendered more soluble in said process stream by said oxidizing or reducing agent; and recycling said process stream for washing additional contaminated particulate material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for removing contaminants comprising heavy metals, radioactive compounds and organic compounds, singly and in combination, from a water-based process stream used in removing said contaminants from contaminated particulate material, said process stream containing a leachate and/or a surfactant, said process stream further including an oxidizing and/or a reducing agent, said oxidizing agent increasing the solubility of said heavy metal in said process stream, said method including the steps of:
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washing said contaminated particulate material with said process stream, thereby removing said contaminates from said particulate material; separating clean particulate material from said process stream, while retaining said heavy metals in solution in said process stream; adjusting the pH of said process stream to 8-10; adding a precipitant to precipitate said heavy metals from said process stream; removing said heavy metals from said process stream; and recycling said leachate and/or said surfactant for washing additional contaminated particulate matter. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34)
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35. An apparatus for removing contaminants comprising heavy metals, organics and radioactive compounds, singly and in combination, from a process stream used in removing said contaminants from contaminated particulate material, said apparatus comprising:
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means washing said contaminated particulate material with said process stream, thereby removing said contaminates from said particulate material; means introducing an oxidizing and/or reducing agent to said process stream, said oxidizing agent increasing the solubility of said heavy metals in said process stream; means separating clean particulate material from said process stream following removal of said contaminants from said particulate material by said process stream; means treating said process stream with a heavy metal precipitant following removal of said clean particulate material therefrom; means removing precipitated heavy metal from said process stream following precipitation of said heavy metal; means treating said process stream after removal of said heavy metal therefrom with makeup oxidizing and/or reducing agent; means recycling said process stream to said means washing said contaminated particulate material.
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Specification