CZ733U1 - Sorbent for fixation of toxic radioactive and contaminating matters - Google Patents

Abstract

The invention solves the use of ashes obtained by combustion of solid fuels at high temperatures e.g. in fuel powder kettles, if desired with addition of a biologically active substance containing bacteria causing destruction of organic matter as sorbent for immobilizing toxic and contaminating components and thus for protecting the environment from contamination with toxic elements or from their incorporation into the biosphere. The invention utilizes high sorption capacity of ashes for a very firm fixation of detrimental compounds that are thus immobilized and cannot penetrate into the biosphere. The biologically active matter, if present, causes decomposition of organic contaminants. This property is utilized e.g. so that between the source of contamination such as a dump, and the environment a barrier of an ash layer is formed, said ash having high sorption capacity so that the contaminants are immobilized by sorption on the ash and, if flooded, water gets through whilst the toxic elements are fixed. Another possibility is filtration of contaminated water through a layer of a sorbent based on the ash. The third possibility is the mixing of the contaminated material e.g. soil, with an ash sorbent.

Description

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The present invention relates to a sorbent for the fixation of toxic, radioactive and polluting substances, composed of ash formed by the combustion of solid fuels at the. at a temperature higher than 10 ° C, eg in a powder furnace, and which consists of at least 30 ib by weight of particles less than 3 mm in size and at most 1C to less than C, 1 mm by weight and has a content of less extensible elements. than 1 mg. and the activity of the radium is less than ICC 3q.kg-1, optionally with the addition of a biologically active substance containing bacteria, destroying organic waste, eg slurry or sewage sludge.

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BACKGROUND OF THE INVENTION

For the disposal of toxic wastes or substrates, many different techniques, preparations and compositions are used. The method of decontamination or remediation depends on many factors, which are always subordinate to the purpose and objectives being pursued.

For the purpose of decontamination or remediation, substances having a high-sorption capacity for the disposal of contaminants by physical chemistry, the product of which has a reduced toxicity or improved capture potential, are used. These sorbents are organic and inorganic substances produced synthetically or of natural origin.

For example, finely ground alfalfa, crushed, needles (03 242324), chemically modified coal (DS 3731920), 03 PV 04756-90, etherified fenclic resins (U3 4323459) or even wool (03 237575) have proven useful for the disposal of toxic heavy metals in waters. ), of inorganic minced steel slag (U3 4377433).

For the treatment of sewage, a similar process of treated brown coal (C3 210955), activated brown coal and benton or calcium oxide and bentonite (03266152), brown coal nutrient, xcxs coal (DE 3913710) or oxidized coal (03 3912339), active In the form of fibers (U3 4576929) or granulated (U3 4954469), paper fiber suspension (U3 4734393), zeolite (US 4927796).

The use of polyurethane foam (08 3713356), wood material (CS 2C3455) or rum crumb (38 392299), optionally with electrolysis (SU 1163512) or electrocoagulation (SU 1139811) is also known for trapping organic matter from wastewater.

Contaminants from water or air can also be absorbed by the adsorbent, the adsorbent being understood to mean a mixture of carbon black and clay according to JP 370260465.

33 3331475, which has as a basic component a fine-grained fly ash with an average grain diameter below 530 µm, solves a means for removing organic and inorganic substances from water. Similarly, adscrbent of O 1,734,543 uses fly ash from all types of ovens. In the biological denitrification of wastewater according to JO 238373, the wastewater is passed through a bed, thereby denitrifying microorganisms trapped on solid waste products from low-temperature brown coal gasification, so-called ash or dust from the in-plane brush generators.

Also, a process for the production of highly porous mineral bodies according to 03 2140399 can produce a means for separation, purification, drying or adsorption. The raw material for the production of this composition is fly ash from the electric filters of a brown-coal-fired power plant and from the sludge from an effluntpurification station. After addition of water, these materials are purged and dried for 3 hours at 150 ° C. This is followed by thermal recovery.

Patent P 730213 may also be used to treat liquids or suspensions, which uses fly ash, which is treated to pass through a 200-mesh screen aperture per inch.

The composition of patent P 3331475.6 also serves to remove organic and inorganic substances, wherein a fine-grained fly ash is also used, which is defined by an average grain diameter of less than 1.5 mm, preferably less than 0.1 mm.

The disposal of odorous substances was dealt with by the Palatý Group (Air Protection 2/1938, 47), which used cinder.

3yló described the use of power. fly ash for the capture of pyridine from waste water (Culíková 3.-diploma thesis VoCHT Praha 1934), reduced phenol content in water by fly ash are described by Giinther and Frctscher (., 'and cssr .virtzchzf t-narrow ooertechnik 11,' _r 16,1961), the thickening of liquid biological waste by ash is the subject of CS AQ 26C625, but here it is a simple filtration. The use of fluidized bed ash (D3 3721251) has been described for flue gas filtration in dry desulfurization.

One of the biggest disadvantages of all organic remediation and decontamination agents is their instability, where, for example, the amount of adsorbed toxic substances is decomposed in the landfill and thus the toxic substances are released. In the case of synthetic sorbents, their selectivity for a given type of contaminant, and especially their high cost, is a defect.

The processes described so far using coal combustion products as a sorption agent do not define the material substantially used, which makes the process not reproducible. In particular, the condition of the composition of the serbent itself is not defined in these processes, so that it does not distinguish the ashes, i.e. the coarser separated particles and the ashes, i.e. the finest particles in which contaminants are enriched. Thus, with the use of fly ash, sorption occurs, but at the same time descent of the kentaminants enriched in fly ash occurs, so that the overall result may be negative even though some substances have been absorbed. On the other hand, the slag, as a very coarse-grained material, has a very small specific surface and therefore its sorption capacity is low. Both the crate and the fluidized bed ash have considerably different properties, since they are formed at temperatures below 1000 ^& 0 and are therefore not remelted by 3 depleted step elements. These deficiencies in the definition of the serbent arise from the fact that the causal link between the physico-chemical properties of ash and its ability to bind toxic and pollutants that contaminate the environment has not yet been known.

- ‘• drunken, ie the smallest particles that are not trapped in the scrubber and escape from the chimneys into the atmosphere, are toxic elements nabohscen. Therefore, its leachate has an increased content of toxic trace elements and is worthless for use in sorptionOezačínský 11., Pilátová 3. - Chemical composition of emissions from coal combustion and other selected technologies - final report of the research institute Fraha 1935; 3.English 11.-immission factors of trace elements of energy sources-candidate dissertation Ú7UT Praha Faculty of Mechanical Engineering 1985; Natusch D.- Characterization of trace elements in fly ash conference on heavy metals Toronto 1975; Ir 'irubý V, Kusý V. - Research of sc.rpce 3 descrpce of sulfur dioxide in the heat from power plants - final report of VÚHU Most 1973; Hrubý V., Kusý V., Ecological problems in coal combustion).

Thus, neither the fluid bed, the fly ash nor the fly ash meet the condition of the sorbent definition according to the invention, where the particle size distribution of the aqueous extract is defined.

The essence of the technical solution

The cutout solves said drawbacks sorbent for fixation of toxic, radioactive and znečižtujících drugs, whose principle consists in that it consists of ashes obtained by combustion of solid fuels at temperatures than you .SI 1ŠCO ^C C KTEP and is formed at least from an AC jo by weight of particles of size less than 3 mm and not more than 1C λ- weight of particles smaller than C, 1 mm, and has a water content of leachable toxic elements less than 1 mg.l ^-i and activity of radium is m ^ NSI than ICO 3q.kg \ optionally by addition of a trace of 2% by weight, expressed as dry matter, of a biologically active substance containing bacteria which is destructive to organic matter, eg slurry or sewage sludge.

Ashes separated in mechanical and electrostatic precipitators are largely depleted due to the high temperature effect of the combustion process.

The portion of the toxic elements remaining in the ash is incorporated in the solid ash 3 and is only partially leachable. However, this ash has the ability to firmly bind both inorganic and organic toxic substances by physical sorption and chemosorption due to disturbed equilibrium and considerable surface area. This ability has ash in dry and fresh state, as well as in wet state, after sailing.

The humid pop9l-remelted alumosilicate forms a layer of hydrated forms on its surface and these hydrated forms of various alumosilicates-hydrogels also function as excellent sorbents. The large specific surface also allows intensive microflora development when the ash is mixed with a biologically active substance, which

decontamination further increases.

The binding of the sorbed pollutants is very strong, so that even long-term drinking water, rain or underwater, counting for more than 5 years, will not wash out toxic and pollutants. In addition, any acidity of the rain is neutralized by the action of the alkaline ash components.

Examples will be done

1. The use of ash as a sorbent according to the technical solution is realized, for example, as follows:

In all cases, the ashes of the power plant with the following composition, expressed as a percentage by mass, were used:

The ash contains 3 λ »particles larger than 3 mm, 7 £ particles 1-gamma, 31» particles 0.5-1 mm, 39 particles 0.2-0.5 mm, 9% particles 0.1-0.2 mm and 6 particles smaller than 0.1 mm. The content of all monitored chi elements in the aqueous extract is less than 0.5 mg / l.

a) A layer of ash c of 0.3 m in thickness was created in the floors and on the walls of the landfill during the toxic waste landfill.

In such a landfill, toxic substances are solidly entrapped but rainwater passes through the landfill so that no drainage problems occur, such as when using clay or plastic sealing layers. No toxic trace elements in concentrations greater than 0.5 .1 were found in the groundwater

b) During the purification of the bathing water, the circulating water of 1 l.s was passed through a layer of ash with a thickness of 0.7 m and an area of 12.5 m ^.

The pH of the water decreased from 3.4 to δ, 3, the ammonia content decreased from 0.3 mg.I ^-1 to 0.15 mg.l \ 3SK ^ decreased from 1.95 to 0.31 mg.l ^-1 .

c) In the treatment of municipal waste water, septic water was passed through a 1.5 m ash layer. The chemical oxygen demand decreased from the original 130 mg.l ^- to 50 mg. l \ biological oxygen demand of 130 mg. 1 ^- ^ 12 ^ rnG.L.

d) industrial fertilizer containing 50 mg Od.kg ^- ^ were mixed with the ash in a weight ratio of 1: 1st Cadmium content in aqueous

leachate dropped to C, 2 mg.l ^.

e) The soil was contaminated with phenol waters at 2 mg phenol per kg. 10% by weight of ash and 20% by weight of sewage sludge containing 5 λ of dry matter were added to the soil. After two months the phenol content dropped to 0.1 mg. In the control sample without addition of ash, the phenol content did not change within the limits of the experimental error.

Fr Industrial usability

The sorbent according to the invention can be used in all cases where it is necessary to prevent the penetration of toxic substances into groundwater or surface water, soil or other components of the environment, or to remove these substances from it, especially they were low concentrations of these substances.

It means cleaning of contaminated sciences, or cleaning of water from sewage treatment plants, landfilling of toxic waste from industry and agriculture, building safety screens near such landfills.

The second area of application is the immobilization of toxic and pollutants which have already been released into the environment, in particular from the soil, eg from fertilizers, industrial or agricultural waste 'or from atmospheric fallout. In these cases, toxic and pollutants remain in the soil, but they are firmly bound to the ash sorption so that their harmful effects do not occur.

In the case of organic pollutants and the use of ash asbestos with the addition of a biologically active substance, not only the contaminant is captured but also accelerated to decompose, so that the sorbent is automatically regenerated and its capacity increases theoretically indefinitely.

The same effect is achieved in the purification of some organically polluted waters, where the contaminant itself initiates a decomposition reaction on the ash surface.

 ln «. Jaroslav Novotný patent attorney 120 00 Praha 2 - Římská 45 tel .: 2514 69

Claims (2)

Protection claims 1. A sorbent for the fixation of toxic, radioactive and polluting substances, characterized in that it consists of ash «produced by the combustion of solid fuels at a temperature higher than 1OCO ° G and consisting of at least 30% by weight of particles of a size less than 3 mm and a maximum of 10% by weight of a particle size of less than 0,1 mm and having a content of water-contained toxic elements of less than 1 mg.l ' ¹ and the activity of ra 'dia is less than 100 Bq.kg ^-1 . 2. Toxic, radioactive and contaminant fixative according to claim 1, characterized in that it contains traces of up to 20% by weight on a dry weight basis, biologically active substances containing bacteria destroying organic matter, eg pig slurry or sewage sludge .