US4409137A — Solidification of radioactive waste effluents

Claim 1

Independent Claim 177 words

A process for enveloping a radioactive waste liquid containing solids, said process comprising the steps of: chemically treating said waste liquid by adding at least one chemical reagent to adjust the pH of said liquid to greater than 7.0; concentrating said solids using a thin-film evaporator having a heated wall and means for distributing said waste liquid as a film on said wall to remove a portion of the moisture from said waste liquid and form a liquid concentrate containing a greater concentration of solids than in said waste liquid; drying said concentrate in a mixing apparatus having a heated wall and rotor means for contacting said heated wall with said concentrate to remove the remaining liquid from said waste and form a solid waste residue, said rotor means including mixing means for shearing said solid waste residue so as to form dry particles and advancing means for engaging said dry particle to positively advance said dry particles toward an outlet of said mixing apparatus; and, enveloping said dry particles of waste material in a second material.

Claim 2

Dependent Claim 177 words

A process for enveloping a radioactive waste liquid containing solids, said process comprising the steps of: chemically treating said waste liquid by adding at least one chemical reagent to adjust the pH of said liquid to greater than 7.0; concentrating said solids using a thin-film evaporator having a heated wall and means for distributing said waste liquid as a film on said wall to remove a portion of the moisture from said waste liquid and form a liquid concentrate containing a greater concentration of solids than in said waste liquid; drying said concentrate in a mixing apparatus having a heated wall and rotor means for contacting said heated wall with said concentrate to remove the remaining liquid from said waste and form a solid waste residue, said rotor means including mixing means for shearing said solid waste residue so as to form dry particles and advancing means for engaging said dry particle to positively advance said dry particles toward an outlet of said mixing apparatus; and, enveloping said dry particles of waste material in a second material.

Claim 3

Dependent Claim 26 words

The process of claim 1 in which said enveloping step includes intimately mixing said dry particles with said second material to form a substantially homogeneous mixture.

Claim 4

Dependent Claim 18 words

The process of claim 2 in which said second material comprises bitumen, synthetic resin, glass or inorganic cement.

Claim 5

Dependent Claim 15 words

The process of claim 3 in which said synthetic resin is a thermosetting polyester resin.

Claim 6

Dependent Claim 27 words

The process of claim 4 in which said thermosetting polyester resin is formed by copolymerization reactions between an unsaturated glycol monomer, orthopthalic acid, and a styrene monomer.

Claim 7

Dependent Claim 21 words

The process of claim 3 in which said inorganic cement contains alumina in an amount of at least 35 weight percent.

Claim 8

Dependent Claim 68 words

The process of claim 2 in which said dry particles are substantially free of free water and said second material comprises inorganic cement previously mixed with water to form an aqueous cement slurry, and in which said slurry is subsequently mixed at ambient temperature with said water-free dry particles and said mixture is allowed to set so as to encapsulate said waste solids in a solid concrete matrix.

Claim 9

Dependent Claim 23 words

The process of claim 1 which further includes removing entrained particulates from the moisture vapor produced by said evaporator and said mixing apparatus.

Claim 10

Dependent Claim 19 words

The process of claim 8 which further includes discharging moisture vapor from said mixing apparatus through said thin-film evaporator.

Claim 11

Dependent Claim 29 words

The process of claim 9 in which said thin-film evaporator includes means for removing particulate solids from the moisture vapor produced by both said evaporator and said mixing apparatus.

Claim 12

Dependent Claim 29 words

The process of claim 1 in which the concentration of solids in waste liquid fed to said thin-film evaporator is in the range of 1 to 30 weight percent.

Claim 13

Dependent Claim 33 words

The process of claim 1 in which the concentration of solids in the concentrate passing from said concentrating step to said drying step is in the range of 30 to 70 weight percent.

Claim 14

Dependent Claim 18 words

The process of claim 1 in which said at least one chemical reagent is lime or barium nitrate.

Claim 15

Dependent Claim 24 words

The process of claim 1 which further includes the step of evaporating said waste liquid in a second evaporator upstream of said thin-film evaporator.

Claim 16

Dependent Claim 25 words

The process of claim 14 in which moisture vapor from said mixing apparatus and said thin-film evaporator is condensed and recycled to said upstream evaporator.

Claim 17

Dependent Claim 25 words

The process of claim 1 in which a portion of said waste liquid bypasses said thin-film evaporator and is fed directly to said mixing apparatus.

Claim 18

Dependent Claim 36 words

The process of claim 2 in which at least a portion of the mixing of said dry particles with said second material takes place in a portion of said mixing apparatus downstream of a drying portion.

Claim 19

Dependent Claim 28 words

The process of claim 2 in which the relative proportion of said dry particles to said second material is in the range of 40 to 70 weight percent.

Claim 20

Dependent Claim 58 words

The process of claim 1 in which said mixing means includes an elongated rotor and said advancing means includes helical means carried by said rotor, said helical means being canted relative to the axis of said rotor and arranged so as to positively advance both said concentrate and said dry particles toward the outlet of said mixing apparatus.

Claim 21

Dependent Claim 47 words

The process of claim 1 in which said concentrate upon drying forms a hardened layer upon said heated wall and said mixing means, and in which said mixing apparatus further includes means for removing said hardened layer of dried concentrate from said wall and said mixing means.

Claim 22

Dependent Claim 22 words

The process of claim 1 in which said chemical treating step adjusts the pH of said waste liquid to greater than 10.

Claim 23

Dependent Claim 28 words

The process of claim 21 in which said chemical treating step adjusts the pH of said waste liquid to a value within the range of 10 to 12.

Claim 24

Dependent Claim 23 words

The process of claim 2, in which said substantially homogeneous mixture is discharged into a container having a wall of water impervious material.

Claim 25

Dependent Claim 23 words

The process of claim 1 in which said chemical treatment step is carried out after said solids are concentrated in said thin-film evaporator.

Claim 26

Dependent Claim 23 words

The process of claim 24 in which both said chemical treatment step and said drying step are carried out in said mixing apparatus.

Claim 27

Dependent Claim 20 words

The process of claim 25 in which said chemical reagent is added in a dry state to said liquid concentrate.

Claim 28

Dependent Claim 20 words

The process of claim 1 in which said chemical reagent is added in a dry state to said waste liquid.

Claim 29

Dependent Claim 22 words

The process of claim 1 in which the dry particles of waste material are calcinated before enveloping them in a second material.

Claim 30

Dependent Claim 180 words

An improvement in the process for solidifying a radioactive waste liquid containing solids wherein the pH of said waste liquid is adjusted to greater than 7.0 by the addition of at least one chemical reagent and said chemically treated waste liquid is heated to solidify said solids by evaporating said liquid, said improvement comprising pretreating said waste liquid so as to form a concentrate containing said solids in an amount of at least 35 weight percent and subsequently feeding said concentrate to a heated mixing apparatus to evaporate said liquid and form dry particles of said solids, said heated mixing apparatus comprising a heated wall for evaporating said liquid from said concentrate so as to form dry solid material; rotor means for working said solid material to form dry particles, said rotor means including a plurality of paddles for working said material and means for positively advancing said concentrate and said dry particles toward the outlet of said mixing apparatus; and means for shearing hardened layers of said concentrate from said heated wall, said helical means, and said working paddles.

Claim 31

Dependent Claim 180 words

An improvement in the process for solidifying a radioactive waste liquid containing solids wherein the pH of said waste liquid is adjusted to greater than 7.0 by the addition of at least one chemical reagent and said chemically treated waste liquid is heated to solidify said solids by evaporating said liquid, said improvement comprising pretreating said waste liquid so as to form a concentrate containing said solids in an amount of at least 35 weight percent and subsequently feeding said concentrate to a heated mixing apparatus to evaporate said liquid and form dry particles of said solids, said heated mixing apparatus comprising a heated wall for evaporating said liquid from said concentrate so as to form dry solid material; rotor means for working said solid material to form dry particles, said rotor means including a plurality of paddles for working said material and means for positively advancing said concentrate and said dry particles toward the outlet of said mixing apparatus; and means for shearing hardened layers of said concentrate from said heated wall, said helical means, and said working paddles.

Claim 32

Dependent Claim 87 words

The improvement of claim 29 in which said waste liquid is pretreated in a thin-film evaporator to form said concentrate, said thin-film evaporator including a heated wall to evaporate a portion of the moisture from said waste liquid so as to form a liquid concentrate containing at least 35 weight percent solids, means for distributing said waste liquid as a film on said heated wall, and means for causing said film to be removed from said heated wall before said concentrate contains less than 30 percent moisture.

Claim 33

Dependent Claim 47 words

The process of claim 1 in which said mixing means includes at least one mixing member and at least one cleaning member, said mixing member cooperating with said cleaning member and said heated wall so as to shear said solid waste residue and form said dry particles.

Claim 34

Dependent Claim 24 words

The process of claim 31 in which at least a portion of said advancing means is carried by said at least one mixing member.

Claim 35

Dependent Claim 43 words

The process of claim 1 in which said mixing means includes a plurality of mixing paddles for shearing said solid waste residue between said paddles and said heated wall and between different ones of said paddles so as to form said dry particles.

Claim 36

Dependent Claim 69 words

The process of claim 1 in which said solid waste material is dried in said mixing apparatus until said waste particles are substantially free of free water; and in which said enveloping step includes adding dry cement and separately adding water to said waste particles and intimately mixing said waste particles, said cement, and said separately added water so as to encapsulate said waste material in a concrete matrix.

Claim 37

Dependent Claim 53 words

The process of claim 1 in which said drying step includes continuously drying said concentrate until said waste particles are substantially free of free water, and in which said enveloping step includes continuously mixing said waste particles with a matrix material to form a substantially homogeneous mixture and then solidifying said matrix material.

Claim 38

Dependent Claim 24 words

The process of claim 35 in which both said continuous drying step and said continuous mixing step are carried out in said mixing apparatus.

Claim 39

Dependent Claim 49 words

The process of claim 36 in which said matrix material is comprised of at least two different ingredients, and in which said enveloping step includes adding said at least two different ingredients separately to said waste particles at different points of addition separated circumferentially and/or axially from each other.

Claim 40

Dependent Claim 17 words

The process of claim 37 in which said at least two ingredients are dry cement and water.

Claim 41

Dependent Claim 27 words

The process of claim 37 in which said at least two ingredients include at least two different chemical compositions for the formation of a synthetic resin matrix.

Claim 42

Independent Claim 241 words

An apparatus for enveloping radioactive waste liquid containing solids comprising: means for treating said waste with at least one chemical reagent to adjust the pH of said liquid to greater than 7.0; thin-film evaporator means for concentrating said waste liquid, said thin-film evaporator means having a heated wall and rotor means for distributing said waste liquid as a thin-film on said wall so as to evaporate moisture from said waste and form a liquid concentrate containing a greater concentration of solids than in said waste liquid; a heated mixing apparatus having a heated wall for drying said concentrate and rotor means for contacting said heated wall with said concentrate to remove the remaining liquid from said waste and form a solid waste residue, said rotor means including a plurality of mixing paddles for shearing said solid waste residue between said paddles and said heated wall and between different paddles so as to form dry particles, and advancing means for engaging said dry particles to positively advance said dry particles toward an outlet of said mixing apparatus; means for discharging said concentrate from said thin-film evaporator to said mixing apparatus; means for causing said waste liquid to pass through said thin-film evaporator and said concentrate to be discharged to said mixing apparatus so that the concentrate received by said mixing apparatus contains at least 30 weight percent moisture; and, means for enveloping said dry particles of waste solids in a second material.

Claim 43

Independent Claim 241 words

An apparatus for enveloping radioactive waste liquid containing solids comprising: means for treating said waste with at least one chemical reagent to adjust the pH of said liquid to greater than 7.0; thin-film evaporator means for concentrating said waste liquid, said thin-film evaporator means having a heated wall and rotor means for distributing said waste liquid as a thin-film on said wall so as to evaporate moisture from said waste and form a liquid concentrate containing a greater concentration of solids than in said waste liquid; a heated mixing apparatus having a heated wall for drying said concentrate and rotor means for contacting said heated wall with said concentrate to remove the remaining liquid from said waste and form a solid waste residue, said rotor means including a plurality of mixing paddles for shearing said solid waste residue between said paddles and said heated wall and between different paddles so as to form dry particles, and advancing means for engaging said dry particles to positively advance said dry particles toward an outlet of said mixing apparatus; means for discharging said concentrate from said thin-film evaporator to said mixing apparatus; means for causing said waste liquid to pass through said thin-film evaporator and said concentrate to be discharged to said mixing apparatus so that the concentrate received by said mixing apparatus contains at least 30 weight percent moisture; and, means for enveloping said dry particles of waste solids in a second material.

Claim 44

Dependent Claim 126 words

The apparatus of claim 40 in which said heated mixing apparatus includes a drying section for forming dry waste particles substantially free of free water and a matrix mixing section downstream of said drying section for forming a substantially homogeneous mixture of said waste and a matrix material comprised of at least two ingredients; and in which said enveloping means includes means for introducing one of said matrix ingredients into said matrix mixing section at one position, separate means for introducing the other of said matrix ingredients into said matrix mixing section at another position spaced circumferentially and/or axially from said position for introducing said one matrix ingredient, and means for solidifying said matrix material so as to encapsulate said waste particles in said matrix material.

Claim 45

Dependent Claim 21 words

The apparatus of claim 41 in which said one matrix ingredient is dry cement and said other matrix ingredient is water.

Claim 46

Dependent Claim 37 words

The apparatus of claim 41 in which said one matrix ingredient is a first chemical composition and said other matrix ingredient is a second chemical composition for forming a synthetic resin matrix with said first chemical composition.

Claim 47

Dependent Claim 21 words

The improvement of claim 29 in which said dry waste particles are enveloped in bitumen, synthetic resin, glass or inorganic cement.

Claim 48

Dependent Claim 13 words

The improvement of claim 29 in which said dry waste particles are calcined.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1986-10-10	1987-04-11	1987-10-11	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1990-10-10	1991-04-11	1991-10-11	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1994-10-10	1995-04-11	1995-10-11	$7700.00	Window Closed / Lapsed

Solidification of radioactive waste effluents

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag