US4376598A
Expired / Lapsed
US
⏱️ 0.0 years remaining
In-situ vitrification of soil
Assignee: United States Department of Energy
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Filing: 1981-04-06
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Granted: 1983-03-15
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Expires: 2001-04-06
Abstract
Abstract A method of vitrifying soil at or below a soil surface location. Two or more conductive electrodes are inserted into the soil for heating of the soil mass between them to a temperature above its melting temperature. Materials in the soil, such as buried waste, can thereby be effectively immobilized.
Inventors
- 👤 Richard A. Brouns
- 👤 James L. Buelt
- 👤 William F. Bonner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:48
CPC Classifications
C; C03; C03B; C03B5/00; C03B5/02; C03B5/027; C03B5/0272; B; B09; B09B; B09B1/00; B09C; B09C1/00; B09C1/06; B09C1/067; C03B5/005; E; E02; E02D; E02D3/00; E02D3/11
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
120 words
A method for in-situ vitrification of soil, comprising the following steps: inserting at least one pair of electrodes into the soil at spaced positions from one another; providing an initial electrically conductive resistance path in the soil across the electrodes; passing electrical current through the electrically conductive resistance path by application of current to the electrodes to heat the soil about the path to its melting temperature, thereby establishing a current-carrying pathway through the molten soil between the electrodes; continuing application of current to the electrodes until the soil between them and immediately adjacent to them has been melted; and terminating application of current to the electrodes to permit cooling and solidification of the melted soil into a solid mass.
Claim 2
Independent Claim
120 words
A method for in-situ vitrification of soil, comprising the following steps: inserting at least one pair of electrodes into the soil at spaced positions from one another; providing an initial electrically conductive resistance path in the soil across the electrodes; passing electrical current through the electrically conductive resistance path by application of current to the electrodes to heat the soil about the path to its melting temperature, thereby establishing a current-carrying pathway through the molten soil between the electrodes; continuing application of current to the electrodes until the soil between them and immediately adjacent to them has been melted; and terminating application of current to the electrodes to permit cooling and solidification of the melted soil into a solid mass.
Claim 3
Dependent Claim
22 words
A method as set out in claim 1 wherein the in-situ vitrification of soil is carried out elevationally above buried waste material.
Claim 4
Dependent Claim
22 words
A method as set out in claim 1 further comprising the step of removing the electrodes from the spoil prior to solidification.
Claim 5
Dependent Claim
24 words
A method as set out in claim 1 wherein the electrodes are inserted through the upper surface of the soil in parallel upright positions.
Claim 6
Dependent Claim
44 words
A method as set out in claim 4 wherein the soil is melted from its surface downwardly to an elevation below the lower ends of the electrodes, and comprising the following additional step: moving the electrodes horizontally within the boundaries of the melted soil.
Claim 7
Independent Claim
151 words
A method for in-situ vitrification of buried waste material surrounded by soil at a waste disposal site, comprising the following steps: inserting at least one pair of electrodes into the soil at spaced positions spanning at least a portion of the buried waste material; providing an initial electrically conductive resistance path in the soil across the electrodes at an elevation above the waste material; passing electrical current through the electrically conductive resistance path by application of current to the electrodes to heat the soil about the path to its melting temperature thereby establishing a current-carrying pathway through the molten soil between the electrodes; continuing application of current to the electrodes until the soil between and immediately adjacent to them has been melted; and terminating application of current to the electrodes to permit cooling and solidification of the soil and any remaining waste materials between the electrode positions into a solid mass.
Claim 8
Independent Claim
151 words
A method for in-situ vitrification of buried waste material surrounded by soil at a waste disposal site, comprising the following steps: inserting at least one pair of electrodes into the soil at spaced positions spanning at least a portion of the buried waste material; providing an initial electrically conductive resistance path in the soil across the electrodes at an elevation above the waste material; passing electrical current through the electrically conductive resistance path by application of current to the electrodes to heat the soil about the path to its melting temperature thereby establishing a current-carrying pathway through the molten soil between the electrodes; continuing application of current to the electrodes until the soil between and immediately adjacent to them has been melted; and terminating application of current to the electrodes to permit cooling and solidification of the soil and any remaining waste materials between the electrode positions into a solid mass.
Claim 9
Dependent Claim
28 words
A method as set out in claim 6 further comprising the following step: enclosing the soil surface area between and immediately surrounding the electrodes within a gas-impervious cover.
Claim 10
Dependent Claim
44 words
A method as set out in claim 6 further comprising the following step: enclosing the soil surface area between and immediately surrounding the electrodes within a gas-impervious cover; and removing gaseous materials from beneath the cover as they are evolved during the vitrification steps.
Claim 11
Dependent Claim
24 words
A method as set out in claim 6 wherein the electrodes are inserted through the upper surface of the soil in parallel upright positions.
Claim 12
Dependent Claim
44 words
A method as set out in claim 9 wherein the soil is melted from its surface downwardly to an elevation below the lower ends of the electrodes, and comprising the following additional step: moving the electrodes horizontally within the boundaries of the melted soil.
Claim 13
Dependent Claim
23 words
A method as set out in claim 6 further comprising the step of removing the electrodes from the soil prior to its solidification.
Claim 14
Dependent Claim
48 words
A method as set out in claim 6 wherein the buried waste materials are arranged in an elongated sub-soil trench, comprising the following step: inserting the electrodes in groups of four spanning at least a portion of the width of the trench and a portion of its length.
Claim 15
Dependent Claim
61 words
A method as set out in claim 6 wherein the buried waste materials are arranged in an elongated subsoil trench, comprising the following steps: inserting the electrodes in groups of four spanning the width of the trench and a portion of its length; and removing the electrodes after termination of current to them and prior to solidification of the molten mass.
Claim 16
Dependent Claim
71 words
A method as set out in claim 6 wherein the buried waste materials are arranged in an elongated subsoil trench, comprising the following steps: inserting the electrodes in groups of four spanning the width of the trench and a portion of its length; removing the electrodes after termination of current to them and prior to solidification of the molten mass; and reinserting the electrodes at a subsequent location along the trench.
Claim 17
Dependent Claim
15 words
A method as set out in claim 1 wherein the buried waste material is radioactive.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-03-14 | 1986-09-13 | 1987-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-14 | 1990-09-13 | 1991-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-14 | 1994-09-13 | 1995-03-15 | $7700.00 | Window Closed / Lapsed |