Classifications

• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
  • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
  • G21F9/04—Treating liquids
  • G21F9/06—Processing
  • G21F9/16—Processing by fixation in stable solid media

Definitions

• the present invention relates to the field of elimination of inorganic and organic waste, including chemical waste and nuclear waste at reduced or medium level and, more particularly, to the field of elimination of waste by microencapsulation. or by solidification. More particularly still, the present invention relates to the field of waste disposal by reacting them with a chemical and a pozzolan-like material to form solid bodies suitable for safe storage or to be sent to the landfill.
• the reacting chemical includes a retarder such as glycerin or other viscosity modifying reactant, or a mixture containing it, and an accelerator.
• incineration processes result in the formation of other undesirable chemicals in the form of ash or gas emitted into the environment.
• incineration is a very expensive which requires very sophisticated incineration equipment as well as transporting the waste to special places where the incineration is to be carried out.
• Another process that was used in the past to dispose of the waste was the solidification of the waste by mixing it with sawdust, various pozzolan-like materials and polymeric substances.
• a disadvantage of such methods lies in their inability to solidify adequately liquid or muddy waste.
• Another disadvantage is that several materials of the pozzo ⁇ lane type used in the past have not been shown to be effective because of their physical or chemical properties.
• the present invention overcomes the challenges of the previous processes by providing a unique chemical reagent and a unique process, this chemical reagent being mixed with the waste and with an extremely active material of the pozzolan type to produce a solid product which is non-toxic, safe, solid, smaller in volume than the waste products resulting from the solidification processes used previously, easily transportable and easily evacuated in a buried landfill site or in natural landfill sites such as salt domes and the like. Furthermore, the present invention discloses a chemical reagent and a method using this reagent in which a pozzolan-like waste material is effectively used to dispose of other wastes, so that two kinds of materials are disposed of simultaneously. waste. The production of the chemical reagent and its use are very simple and economical.
• Inorganic and organic wastes including chemical wastes and nuclear wastes at low or medium level are solidified by mixing them with a reacting chemical and with a pozzolan-like material.
• This reactive chemical includes a retarder, which may be glycerin or other viscosity-modifying reagents, and an accelerator, namely calcium chloride.
• the retarder prevents rapid setting of pozzolan-like material and slows down the setting process, while the accelerator promotes the activity of the solidification.
• the retarder acts as a lubricant and improves viscosity.
• the pozzolan-like material may be not only material such as pozzolan specifically manufactured in cement production operations, such as Portland cement, but also waste materials produced in several industrial installations such as fine light particles, entrained by air, oven dust and dust from a recovery filter in a steel or lead production facility.
• the solid waste material formed can be subsequently stored or deposited in natural storage locations without disturbing or harming the environment.
• a reactive chemical has been developed which has unique properties for solidifying organic and inorganic waste, such as low and medium level chemical waste and nuclear waste and for its safe disposal.
• the chemical reagent is mixed with the waste and with pozzolan-like material to form a solid waste material. It is essential that the mixing stage and those annexed are carried out simultaneously or in a particular sequence, described below, to obtain the desired results.
• the reactive chemical consists first of all of a retarder and of an aqueous solution of an accelerating compound.
• the retarder is glycerin, a well-known compound readily available on the market or another viscosity-modifying reagent.
• the retarder can also be glycerin in combination with other viscosity-modifying reagents.
• Other retarders may be used, alone or in combination, depending on their availability, economic considerations and the properties of the waste.
• glycerin constitutes a suitable retarder and could be used, alone or with other retarders, in different compositions for the various applications in accordance with the present invention, it is preferable to use glycerin in most applications because of its superior slowing and lubrication properties.
• the retarder prevents a "flash” setting and slows the setting and solidification of the pozzolan-like material when it is mixed with water and waste. It is estimated that the retarder coats the waste particles to slow solidification. The slowing down of solidification provides sufficient time to uniformly mix the pozzolan-like material and the waste, so as to achieve uniform encapsulation and regular bonding of the waste into the resulting waste product. In addition, the longer setting time provides greater mechanical strength in the resulting waste product.
• the retarder acts as a lubricant. As a lubricant, the retarder provides lower viscosity and therefore friction reducing properties to facilitate mixing of the chemical reagent, waste and pozzolan-like material as described below.
• the preferred accelerator compound is calcium chloride (CaCl-) which promotes the setting of the pozzolan-like material.
• the chemical reagent can also include other solvents which remain neutral during the solidification operation in question.
• the reactive chemical is prepared by mixing an aqueous solution of calcium chloride with the retarder using techniques of well-known mixture.
• the amount of calcium chloride present in the aqueous solution which serves as the starting material for the chemical reagent, can range from 15 percent by weight until saturation.
• the amount of retarder used in the chemical reagent depends on the desired retardation and viscosity properties and the properties of the waste which is treated. If, for example, it is desired to have a longer setting time, the quantity of retarder is increased, which means that the resulting waste product is harder and more resistant. In a typical ⁇ "application, the amount of retarder can range from 0.01 to 15 parts of retarder per 100 parts of reactive chemical in diluted form.
• the chemical reagent is a homogeneous and non-toxic solution which retains its homogeneity and stability for a long time.
• the reagent could be easily stored at temperatures ranging from -40 ° C At 35 ° C. and above As the retarding and accelerating compounds are inexpensive and the mixing operation is simple, the reactive chemical is also inexpensive.
• pozzolan-like materials can be used, including fine particles entrained by air in coal-fired power plants, including light Class C fine particles known for their high calcium content and light fine particles.
• Class F characterized by their high content of silica and aluminum oxides; dust from cement kilns, dust from lime kilns, characterized by a high calcium content, dust from the recovery filters in the steel or lead production facilities; dust from silica vapors in the refractory industry; gypsum, and Portland cement.
• the majority of pozzolan-type materials that are listed here could be characterized as waste materials.
• pozzolan-type waste materials are used to dispose of other wastes, including chemical wastes and low level radioactive wastes and at medium level.
• pozzolan material used to practice the present invention will depend on the availability of such material at the particular location, the price of this material, the needs of the installation generating the waste and the regulations of the authorities. monitoring. In certain regions of the United States for example, in which light fine particles are available in large quantities, these so-called fly ash particles will be used. In special circumstances, the nature of the waste to be treated may require the use of pozzolan-type materials with a higher calcium content, such as Portland cement dust or lime kiln to carry out the cementing operation. .
• the use of the reactive chemical described here makes it possible to use a material of the pozzolan type which has a large reactive surface, which makes the material in question react more easily with the waste and forms a product of resulting waste which has a high density and small pores.
• the pozzolan material used has small and uniform powder component particles with a high content of calcium and other cementing elements.
• flying centers are a pozzolan material which consists of very small uniform spherical particles. Consequently, these ashes have a higher capacity to absorb, react or trap the constituents of hazardous waste. But these ashes tend to set very quickly when mixed with water and waste. Consequently, their use without the reactive chemical of the present invention would not be practical.
• these ashes include a relatively small amount of calcium, a material which contributes to mechanical strength and to the bonding forces of the resulting waste product. Therefore fly ash alone will not produce a solid compound containing waste and having high mechanical strength.
• a very important aspect of the process disclosed in the present invention is the condition that the mixing stage, the union stage of the components and the auxiliary stages are carried out simultaneously or in a specific sequence in order to obtain optimal results.
• the following stages depend on whether the organic or inorganic matter to be treated is liquid or solid waste. It is to be understood that the term "solid waste” which is used in this description and in the claims should refer to waste which includes less than about 15 percent of liquid in free form.
• liquid waste used here must mean waste which includes more than about 15 percent of liquid under free form. If the waste is liquid waste as defined here, it is essential that the liquid waste be mixed first with the reactive chemical product in a conventional mixer suitable for this mixture for a sufficient time to obtain a uniform distribution of the chemical product. reagent in liquid waste.
• the resulting mixture comprising the liquid waste and the reactive chemical product distributed uniformly, is fused or mixed with the pulverulent pozzolan material for sufficient time to obtain a complete and uniform mixture.
• the mixed product is allowed to solidify to form solid bodies of waste. It may be desirable to pour the mixture into molding containers or into molds to form solid waste having predetermined shapes, such as blocks, for ultimate disposal.
• the process for liquid waste is carried out in a continuous mixer.
• the continuous mode of operation can be performed using well known mixing and fusing equipment.
• the mixing of liquid waste with the reactive chemical can be carried out in a mixing pump or in a series mixer and the mixing of the resulting mixture and fly ash can be carried out in a mixer of the screw or ribbon type.
• the process for liquid waste is carried out in the continuous mode, it is possible to use a batch mode, in particular when only a relatively small quantity of waste requires solidification.
• the process can be carried out in a central mixer of the batch type.
• the waste to be treated is solid waste as defined above, it is first mixed with the pozzolan pulverulent material until a uniform mixture is obtained.
• water is added to the reactive chemical to bring the chemical to an optimal water content that is required for the treatment of the solid waste in question.
• the reactive chemical is added to the uniform mixture including solid waste and pozzolan-like material and the whole is mixed for sufficient time to obtain a uniform mixture. Then the resulting mixture is allowed to solidify to form solid waste.
• the treatment of solid waste can also be carried out efficiently by simultaneously carrying out the stages mentioned above.
• the solid waste treatment can be carried out either in batches or continuously using well known devices which can be compared to the devices used in the solidification of liquid waste previously described.
• a preparatory stage lies in the neutralization of waste, whether acidic or basic, using well-known neutralizing agents. such as sodium, lime, etc. , to obtain a preferred pH.
• Another preparatory stage which is more applicable to solid wastes and " liquid wastes which contain solids, is the grinding of the solid components of the wastes to increase the surface area of the solids contained in the wastes and to reduce the size of the wastes.
• Another preparatory stage applicable in the treatment of solid waste containing liquids implies that the drying of the solid waste before mixing with the reactive chemical and pozzolan-like material. Drying and grinding of the waste can be carried out in well-known devices such as a rotary dryer and grinder.
• the process of the present invention can be used to treat a wide variety of organic and inorganic waste, including low and medium level chemical waste and nuclear waste, which are produced by industrial processes and other applications including, but not limited to, heavy oils and aromatic tars, tars of creosote sludge, tank bottoms, heavy petroleum oils, tars and sludges; heavy oils and petrochemical tars and all related products and tank residues including polymers; halogenated organic sludges containing PCBs, dioxins and other bottoms of chlorinated solvent manufacturing tanks; pesticide / herbicide sludges including arsenic; organic and inorganic sludge and waste including the cleaning of leaded tank bottoms; inorganic sludge, electroplating and metallic finishing sludge and soil contaminated with waste, chloride, zinc, etc .; oil contaminated with PCBs and dioxins, stains and stained floors; waste gases adsorbed or trapped in solids or absorbed in liquids, and
• the process used is the same as the process for solidifying liquid waste.
• a pozzolan-type material from a dust from a purification filter from a steel or lead production installation, containing a high content of lead so as to obtain a filtration of lead for nuclear waste emitting radiation.
• the amount of reactive chemical and pozzolan-like material used to treat various wastes depends on the kind of wastes being treated and the specific conditions of the process. In typical applications, the amount of chemical ranges from 16.3 to 130.5 millimeters of reactive chemical per kilogram of waste material that is processed and the amount of pozzolan-like material ranges from 94 grams to two ( 2) kilograms of pozzolan-like material per kilogram of waste material. In the treatment of liquid waste containing solids, the amount of pozzolan-like material required decreases while the amount of suspended solids in liquid waste believes. It is preferable that before treating waste, laboratory tests are carried out on the particular waste in order to determine the optimal quantity of pozzolan material and chemical reagent required.
• the reacting or "reactive" chemical, pozzolan-like material and the waste are bonded together and integrated into the solidification process which changes the physical and chemical properties of the waste.
• the operation decreases the coefficient of permeability and the material plasticity index while increasing the internal mechanical resistance, by forming a mass supporting loads by solidification.
• the process carries out a microencapsulation surrounding and sealing the part of the matrix which is not chemically incorporated in the reaction, which causes the ingredients to become microencapsulated in the interstices formed by the particles of pozzolan material and practically impermeable and without possible leaks. .
• the reactions between the multiple components are well distributed on the surface of the particles, throughout the mass of the waste.
• waste materials play an active role in the process and function separately as a chemical reagent and also contribute to material hardening and the reduction of permeability and percolation characteristics.
• the volume of waste obtained is smaller than that of the product resulting from the solidification operations previously used in the prior art.
• the solid bodies formed by the present process can be safely transported and stored in various places, such as buried dumping sites.
• a special location for to store such solid bodies of waste will be constituted by the salt caves existing throughout the territory of the United States. This storage can be carried out by placing the solid bodies directly in the discharge site or by pumping the residual sludge, before solidification, into a salt cavern where it is allowed to solidify by permanent storage.
• Example I One hundred (100) grams of waste, in the form of acidic residual sludge, containing 7.50 percent by weight of solid matter, was mixed with ten (10) grams of a chemical reagent containing 0.125 grams of glycerin, 0.125 gram of polyethylene glycol and 9.7 grams of 39 percent solution of calcium chloride in water, i.e. about 3.8 grams of calcium chloride and 5.9 grams of water. Then one hundred (100) grams of lime dust was distributed in the above-mentioned mixture. The resulting mixture was poured into molds. The setting time was approximately five hours and the final setting time was ten (10) hours.
• Example II One hundred (100) grams of waste, in the form of acidic residual sludge, containing 7.50 percent by weight of solid matter, was mixed with ten (10) grams of a chemical reagent containing 0.125 grams of glycerin, 0.125 gram of polyethylene glycol and 9.7 grams of 39 percent solution of calcium chloride in water, i.e. about 3.8 grams
• Example III The operation of Example II was repeated using fifty (50) grams of fine particles (fly ash) class "C" instead of 15 grams of Portland cement.
• Example IV One hundred (100) grams of dry earth and fifty (50) grams of fly ash class "C" were mixed. In a separate container, five (5) parts of water (13.5 grams) were added to one (1) part of chemical reagent (4.0 grams) containing 0.05 grams of glycerin, 0.05 grams of polyethylene glycol and 3.9 grams of 39 percent calcium chloride solution in water to form 17.5 grams of diluted chemical reagent. Then the diluted chemical reagent was added to the mixture of earth and fly ash and allowed to solidify.
• chemical reagent 4.0 grams
• diluted chemical reagent 17.5 grams were formed by adding two (2) parts of water (9.5 grams) to one (1) part of chemical reagent (8.0 grams) containing 0.11 grams of glycerin, 0.11 grams of polyethylene glycol and 7.78 grams of 39 percent solution of calcium chloride in water. Then the diluted chemical reagent was mixed with one hundred (100) grams of moist earth. The resulting mixture was mixed with fifty (50) grams of class "C" fly ash. The resulting mixture was allowed to solidify.
• Example VI One hundred (100) grams of residual sludge from an oil separator containing forty (40) percent by weight of solid matter was __, __ . _ _ 89/00752 ''
• Example VII The operation of Example VI was repeated using five (5) grams of the same chemical reagent. 10
• Example VIII The operation of Example VI was repeated using five (5) grams of the same chemical reagent. 10
• Example VIII The operation of Example VI was repeated using five (5) grams of the same chemical reagent. 10
• Example VIII The operation of Example VI was repeated using five (5) grams of the same chemical reagent. 10
• Example VIII The operation of Example VI was repeated using five (5) grams of the same chemical reagent. 10
• Example VIII Example VIII
• Example VI One hundred (100) grams of the mud from an oil separator containing sixty (60) percent by weight of solids was mixed with 2.5 grams of the same chemical reagent used in Example VI. Then sixty (60) grams of light ash class "C" was added and distributed in the mixture.
• Example IX The operation of Example VIII was repeated using five (5) grams of the same chemical reagent.
• Example X One hundred grams of chromium plating waste, containing 7.5 percent by weight solids, was mixed with 2.5 grams of the same chemical reagent as that used in Example IX. Then 75 grams of light ash class "C" were distributed in the mixture and the resulting product was allowed to solidify,
• Example XI The operation of Example X was repeated using the same waste, with 15 percent by weight of solids.
• Example XII The operation of Example X was repeated, using five (5) grams of the chemical reagent.
• Example XI The operation of Example XI was repeated, using five (5) grams of the same chemical reagent.

Landscapes

• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• High Energy & Nuclear Physics (AREA)
• Processing Of Solid Wastes (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=25382444

Family Applications (1)

Country Status (10)

Cited By (1)

Families Citing this family (3)

Citations (4)

• 1987
  • 1987-07-07 CA CA000541526A patent/CA1280449C/en not_active Expired - Lifetime
  • 1987-07-07 AT AT87401702T patent/ATE81563T1/de not_active IP Right Cessation
  • 1987-07-07 ZA ZA874912A patent/ZA874912B/xx unknown
  • 1987-07-07 EP EP87401702A patent/EP0258088B1/en not_active Expired - Lifetime
  • 1987-07-07 ES ES87401702T patent/ES2052592T3/es not_active Expired - Lifetime
  • 1987-07-07 DE DE8787401702T patent/DE3782218T2/de not_active Expired - Fee Related
  • 1987-07-08 CN CN87105717A patent/CN1011931B/zh not_active Expired
  • 1987-07-08 MX MX007248A patent/MX170108B/es unknown
  • 1987-07-20 WO PCT/FR1987/000266 patent/WO1989000752A1/fr unknown
• 1993
  • 1993-01-14 GR GR930400050T patent/GR3006795T3/el unknown

Patent Citations (4)

Also Published As

Similar Documents

Legal Events