Method of processing solid or melted substances. RU patent 2484152.

FIELD: metallurgy.

SUBSTANCE: solid or melted substances are loaded on graphite body heated, at least, partially, inductively. Reducing agents are introduced therein, other than graphite carbon to collect flowing reduced and/or gasified melt. Note here that reducing agents are introduced along with solid or melted loaded particles. Said reducing agents represent natural gas, coal dust, brown coal dust, hydrocarbons, hydrogen, carbon oxide and/or ammonia to be introduced together with steam, oxygen, carbon dioxide and/or halogens or halogen hydrides.

EFFECT: simplified process.

18 cl, 5 dwg

The technical field to which the invention relates

The invention relates to a method of recycling or recovery of solid or molten substances and/or , in particular light fractions generated during grinding, crushed old tires containing oil scale when the rolling production, polychlorinated biphenyls (PCB) - contaminated old wood contaminated dredged material (dioxins or furans), residue from the distillation of oil and dried sewage sludge.

The level of technology

Dust and toxins, in particular waste slag, light fractions grinding, composite materials, such as having a coating of aluminum foil, slag after smelting of steel and slag not ferrous metallurgy and the resulting technology of inorganic materials, contain a number of metal oxides, in the case of slag from the steel in the slag there is an increased the number of heavy metal oxides.

For the recovery of such unwanted metal oxides and, in particular, oxide of chromium, vanadium, molybdenum, tungsten, cobalt, manganese, lead and zinc suggested introducing liquid melts in the appropriate rehabilitative bath molten metal, in particular iron, which as a reducing agent contains dissolved carbon, and recovered metals are moving into the grains of pure metal. But for cost-effective implementation of such method, at least, require the use of source materials directly in the form of the melt to be able to use the sensible heat flux. When all this kind of redox reactions slag is melted metal in equilibrium and because of the conditions of equilibrium of oxides of heavy metals cannot be fully restore a way that remaining in the slag oxides would analytical boundary detection. This applies, in particular, the oxides of chromium and vanadium, which restored the slag remain in quantities, at least over 1000 parts per million.

Glass and, in particular, melts the glass can be produced colorless only when removed them from even very small traces of oxides of heavy metals and metal oxides give to the glass its color. Further, when or molten glass by all the rules need cleaning to reliably remove the small bubbles of gas that arise with the processes of recovery, with the elimination of metal oxides. It is possible only at high temperature, and the correspondingly low viscosity of melts, and at relatively low levels baths, which still allows the escape of gases.

In this regard, WO 2006/079132 suggested download particulate matter and/or melt on, at least partially, inductively heated layer or in a column with a lump Cox and collect flowing restored and/or melt. Such a coke layer in comparison with the famous baths of molten metal has a much higher potential for recovery, and, as melting, and a revival takes place directly at the coke layer or directly on the pieces of coke. The disadvantage with this method, however, was that coke layer has a relatively high sulphur content and the method must be carried out only under very high induction frequencies and thus at relatively high costs of the electrical equipment. Corresponding frequencies ranged from 50 to 100 kHz, which again led to that applied energy due to surface effect could be implemented only on the external edge of the coke layer. So it is sufficient to heat the coke layer in the middle of the backfill would need more power, as the transfer of heat from the inductively heated marginal zone in the middle through the layer of coke occurs only in a very small extent. The known method had, moreover, the lack of that coke in the course of the reaction recovery gradually consumed and therefore required its constant addition, in consequence of which were necessary require expenses related activities of the additional equipment. Problem was, in particular, the fact that when downloading a cold coke on a hot filling of coke was broken down into fine dust, so that no more could be obtained sufficient porosity backfill, and had to put up with high pressure loss.

Disclosure of the invention

The aim of the invention is improvement of this method is that with the elimination of the above shortcomings especially simple and effective method from a large number of oxides of heavy metals could be released not only solids, but also melts, and, in particular, could have removed a number of oxides heavy metals content is below the lower limit of detection, while it should be ensured for degassing or full cleaning of loading or formed in the course of ways melts. In particular, there should be opportunities easiest way to recycle problematic substances such as light fractions generated during grinding.

To solve this problem the proposed method according to the invention consists mainly in the fact that solid or molten substance is loaded on, at least partially, inductively heated graphite body, introduced reducers, other than carbon and graphite going flowing restored and/or melt, and reducing agents are introduced together with solid or melted downloadable substances and as the reducing use natural gas, dust brown coal, hydrocarbons, hydrogen, carbon monoxide and/or ammonia entered together with water vapor, oxygen, 2 , and/or Halogens or .

Due to the fact that reducing agents no longer produced the inductively heated filling, but entered, in particular, together with solid or melted downloadable for processing of substances or as solid or molten downloadable substances or , inductively heated graphite body not spent or allocated only to a small extent, due to which you can completely abandon that costs devices for adding. Due to the fact that graphite backfilling, mostly not consumed, it becomes possible to regulation as axial and radial gradients of parameters of graphite in the filling. For example, to optimize the temperature and on the flow of the conditions for obtaining the relevant effects on the place is influenced by the size, the form, content crystals, as well as electrical conductivity of certain graphite phone In addition to those already mentioned source materials can also be oxidized, thermally pre-treated dust in the steel industry. Lead, halogen and alkali removed when thermal pre-treatment outside the reactor, resulting from the waste gases of the proposed according to the invention of the method retrieves a very pure zinc, if necessary, in the form of oxide.

The restorer is introduced as a component of solid or molten downloaded for processing of substances or is separate from the downloaded for processing of substances.

Light fraction of generated during grinding, loaded on graphite and gasified at a temperature of about 1500-2000°N Due to the high temperature and restorative atmosphere of dioxins, furans and PCB can immediately to decompose. Similarly may resin. The resulting pyrolysis coke gasified by adding a steam and/or oxygen. Perhaps contained sulphur dissolves in the form of calcium sulfide in the respectively selected slag. Metal components and slag components melt and can be separate. The resulting contaminated gas is evacuated for treatment and there are cleared. Introduced water vapor and oxygen as means the cleaned gas is not diluted with air and therefore does not contain oxides of nitrogen (NOx).

Gas preferably finds use as a reducing gas in blast furnaces or in the direct reduction, as alternative fuel gas kilns cement clinker, for various metallurgical (pre-heating) stoves, for direct use (e.g. in gas engines) or for the synthesis of Fischer-Tropsch process due to its high content of N 2 .

Due to the loading of solid particles and/or melts on inductively heated graphite body and the introduction of reducing agents, it becomes possible to provide heat energy is required to recover regardless of proceeding reactions recovery. The graphite gasket body can be formed layer, column or filling of bulk graphite. As an alternative to the graphite gasket body may be established in the form of graphite block with penetrating TV, holes, etc. Common to these variants is that between the graphite pieces layer, columns or backfilling and respectively in the channels or holes in the graphite block remain available cavity in which the reduction is mainly in the gas phase. Recovery in this free cavities graphite body can occur instantly, and thanks to the high-turbulent and surface forces there is also agglomeration melt. Reaction mechanism can contain as an indirect restoration of metal oxide carbon oxide to metal and carbon dioxide or hydrogen to metal and water, and direct recovery of metal oxide carbon to metal and carbon oxide. Carbon dioxide, in turn, with the help of reactive carbon turns into carbon monoxide and water formed through the reaction of the conversion of water gas reacts with carbon with the formation of hydrogen and carbon monoxide.

Due to the fact that the proposed method according to the invention allows separately provide the necessary heat energy and to introduce reducing agents, can be used a number of different reducing agents and actually used the restorer can be chosen in accordance with the requirements of recovery and economic considerations.

Graphite, which has a very good electrical conductivity, connects already at significantly lower induction frequencies and, in particular, at frequencies in excess of 0.5 kHz, so the above deficiencies in terms of electrical installations can be removed. Electric conductivity graphite decreases with increasing temperature. However, due to the fact that already at lower induction frequencies connect graphite, prevents pronounced surface effect, so that the spent energy can penetrate deeper in the cross-section of graphite of the body and thus provide a uniform induction heating. Induction frequency can be chosen freely among a wide range, so you can choose a higher frequency to deliberately get stronger surface effect. This can be useful if marginal zone is heated so much that due to the high viscosity of gases in the hot marginal zone the most part of the reaction gas focuses in the middle of the reactor, and the refractory material of the reactor due to the conditional viscosity minimize the metabolism is protected in the marginal zone. At the same time, thermal conductivity graphite many times higher thermal conductivity of coke, so that in addition to the uniform inductive heating by heat conduction align temperature throughout the cross-section of graphite body.

According to the preferred implementation the present invention method can be enhanced to achieve solid or molten substances and reducing agents other than carbon graphite, and if necessary, solid or molten downloadable for processing of substances are sucked into the graphite layer. This may be due to the fact that throughout the axial length of the graphite filling regulated pressure gradient, which forces particles and gases flow from the end of loading of filling by the end of the release. Thus, it becomes possible for the reliable application of the proposed method according to the invention.

If, in accordance with the preferred form of the implementation of the present invention, as a reducing agent is injected coal dust or dust brown coal, that can be achieved is many times greater potential recovery compared with the potential for recovery coke layer (see WO 2006/079132 A1). Coal dust inhalation or deletion of the available cavity inductively heated graphite body together with similarly entered oxygen/steam immediately turns into carbon monoxide and hydrogen, thus providing very effective restoration of the original substances. Another advantage is that, that the coal dust is much cheaper coke. Dust of brown coal, which is universally available at a reasonable price, especially suitable for implementation of the proposed method according to the invention. When using brown coal completely solved the problem and the cost of the removal of sulfur from gaseous waste, on the one hand, due to the fact that compared with a very clean coal dust containing a relatively large number of foreign matter, dust brown coal pyrolysis leads to the formation of large amounts of volatile substances have a high potential for recovery, and on the other hand due to the fact that a relatively high proportion of the sulfur contained in the brown-coal dust, completely in the slag faction.

Way preferably improved to achieve solid reductants are entered using the carrier gas and, in particular, nitrogen, 2 , 2, or air. This provides, on the one hand homogeneous distribution subject to reconstruction or melt materials on the surface filling and on the other hand prevents the formation of large quantities of gas, thus preventing excessive release of particles from the backfill and limited to loss of pressure in the filling.

Downloadable for processing of substances preferably be loaded directly on heated up to red graphite body, due to which in the proposed method according to the invention at high temperatures due to the relatively thin layer, is achieved, for example, fast degassing or cleaning of glass melts. In General, with inductively heated graphite body and, in particular, with inductively heated layer or a column with a lump graphite without difficulty can be achieved with a temperature of 2000 OC and more. The use of lump material serves primarily to provide the necessary permeability to gases and melts.

According to the preferred form of the method of the present invention improved the fact that graphite is used in the form of beads, cylinders, blocks, granulated molded grains and/or scrap electrodes. Due to the appropriate choice of geometrical form, in which graphite is present in the filling, bulk density and thus the expected pressure loss can be adapted to the relevant conditions. Especially favorable cost and very appropriate for the geometry of the form is the use of graphite in the form of used electrodes and used graphite cathode aluminium electrolysis (spent pot lining) applicable in the manufacture of electrolytic steel. Spent pot lining, containing up to 15% of alkalis and up to 1% CN (cyanide), is used graphite electrodes of primary aluminium production and pose an enormous problem associated with disposing of waste worldwide. When you use the spent pot lining at a temperature of >900 C decomposition cyanide (HCN→H 2 +With+N 2 ), and alkali pass into slag. When using water vapor NaCN of spent pot lining enters Na 2 O slag in accordance with the following equation:

NaCN+H 2 O→Na 2 O+HCN

Size graphite tel lies in the range from about 5 mm to about 5 cm in diameter.

Graphite body in a preferred variant can also be formed from a mixture of graphite and the catalyst powder, which was pressed and, if necessary to give the filling of the special catalytic properties and adapt accordingly emerging chemical and physical requirements of the process. In this regard, according to the preferred form of the implementation of the present invention also possible to produce graphite body with relevant salts and/or metals or ceramics for regulation of the electric conductivity.

To optimally adjust the properties of bandwidth flows graphite backfilling or column, the proposed method according to the invention improved if they graphite tel regulate their micro-porosity. The proposed method according to the invention preferably carried out in such a way that the inductive heating is carried out by submission current with two different frequencies, and selected low and high frequency. High frequency preferably in the range from 3 to 15 kHz and is used for inductive heating of graphite. Low frequency preferably lies in the area of below 0.5 kHz and creates on graphite bodies of the Lorentz force, due to which they are set in motion. Because of this hot recovered material downloaded mixed graphite bodies thanks them impulse. The mixing effect significantly speeds up response due to the mass load/heat transfer.

To prevent the formation of conductive bridges, near adjacent to each other pieces of graphite and emerging due to this heat loss method preferably carried out in such a way that the graphite gasket body entered as backfilling of graphite and inert nozzle bodies, in particular the catalytically active bodies containing Cao or MgO. Inert hook body largely prevent direct contact between the individual pieces of graphite, allowing each piece of graphite forms a separate heating cell.

The preferred way proposed according to the invention of the method is so that together with uploaded substances download contains Zn dust steel mills for linking sulfur (ZnO+H 2 S→ZnS+H 2 O).

Device for recycling or recovery of solid or molten substances and/or , in particular light fractions generated during grinding, provided the charging hole for solid or molten material and an outlet for processed melt. This kind of devices, primarily contain or enclosure containing graphite body and the surrounding case the heating device for induction heating of graphite body, containing at least one telecoil. For the regulation of redox potential or for local cooling design preferably made so that attached to the chassis pipelines for the supply of gases. Especially in a simple way, the design can be made so that the housing is made of electrically insulating material, such as Al 2 O 3 or MgO, or, at least, electrically insulating foil or Mata and is surrounded by a cooled induction coil. This electrically insulating foil can, for example, form resistant to high temperature chrome-corundum mats, and at the beginning of mechanical stability is achieved thanks to a water-cooled induction coil. When loading the molten material or education melts electrically insulating foil quickly covered with a molten slag or as telecoil accordingly cooled, resulting mechanical resistance columns significantly improved and simultaneously completely eliminated the problem with refractory material. However, you can also put induction body with the help fill in refractory mass, so induction housing can take on mechanical properties. Refractory mass may consist of magnesite, spinel or corundum, as well as refractory concrete.

To have a simple possibility for each section to change the temperature of the graphite body, in particular, layer, or columns with lumpy graphite, design preferably made so that the magnetic coil in the axial direction hull is divided in several sections, preferably, that for the following one after the other sections case, there are separate devices for measurements of temperature and/or device for measuring the power consumption due to temperature and oxidation-reduction mode in the individual sections can be governed by a regulation of electric power and/or subject to the introduction of gases and/or volume of injected gas.

The device is made in such a way that axially after restoring zone, located in the area of the heating device, is a restful area. In this zone, reaction products formed in the reaction zone mix and in the form of melt drops in a homogeneous gaseous product. A restful area is the preferred way shall be of such dimensions that the length of the axis restful zone is from one to two diameters shaped pipe casing, resulting in sufficient mixing of gases and at the same time, available in the gas phase solid particles may still be translated into the melt. To reduce the rate of flow the diameter of the reactor preferably implemented in this area.

Below invention explained in more detail and with examples of the implementation of the device, schematically represented in the drawings. Of them figure 1 shows the construction of the reactor for the placement of graphite columns for the method according to the present invention, figure 2 shows a different design reactor, figure 3 presents the technological scheme of the method, which shows the integration of the proposed according to the invention, the way in industrial application, figure 4 shows the preferred version of the boot device and figure 5 shows the preferred form of the implementation of the adaptation to upload a large number of the original dust.

Chamber 11 separation of reactive gases from the molten metal, and gases can be discharged through the hole 12, and the melt flows through the outlet 13. Position 14 marked the opening through which may be updated graphite filling 16 by adding, for example, graphite balls or scrap electrodes. The axial length, i.e. in the longitudinal direction of the axis of 15 reactor, gas supply and by regulating the temperature can be regulated as redox gradient and the temperature gradient, which can successfully be achieved in the area of release 13 formed produced toxins and metals, not containing oxides of iron oxides and heavy metals, and also avoids the problems associated with refractoriness in this area.

Enclosure wall 3 reactor 1 can be formed refractory foil, which in the course of melting or melt wetted by the melt, which forms a cover of slag or melt. Reel 8 established in the form of cooled water copper conductor provides a cooling wall that leads to the formation of the coating layer, consisting of slag or melt.

Between the boot device 4 and graphite body 16 can be located in zone 17 prior combustion or pre-heating, which can include at least one pipeline (not shown) for the filing of the energy carrier and/or oxidative gas prior to combustion or pre-heating.

Subsequent combustion in the end of boot/end of release and in the graphite column, which is burned WITH the conversion FROM 2 , is possible in principle, and leads to greater efficiency through the introduction of heat. Very inert surface of graphite filling the partially covered by the molten slag, so that the reaction of the Boudoir with carbon graphite largely suppressed.

Metal melt, educated in the graphite column, can also feast on carbon using coal dust or form in a bath of molten metal dispersed carbides such as, for example, carbides metals: iron, vanadium, chromium and tungsten. Fundamentally able to restore chrome using relatively short graphite columns from slag up to concentrations below 60 ppm. In particular, when «tertiary slag», which apply to the method of electroslag remelting» for production of high-grade constructional and tool steels, clean toxins attached the greatest importance. Slag consists mainly of one-third (by weight) of the CaF 2 (fluorspar), one third of the Cao (quicklime) and Al 2 O 3 (corundum), as well as in some cases of MgO, SiO 2 and the like. To get these toxins proposed according to the invention method is especially suitable as impurities N, R, S, N 2 , p, Pb, Bi, CN, Na, K and can be deleted especially effective. At the present time, these toxins are melting ultra high purity of initial substances in electric arc furnaces. However, the high temperature (about 8000°, plasma) in the electric arc furnaces and electrode material (graphite) produce very undesirable carburising and education carbide CA and Al, and also partially residual sulfur from graphite electrodes. Similarly in these slag dissolved nitrogen from the air. Possible other impurities remain in the slag produced.

In contrast, the proposed method according to the invention provides a number of advantages:

- significantly lower temperatures, evenly distributed, well-adjustable the level of temperature, no temperature peaks (inductively heated layer of graphite tel),

- restore partial volatilization undesirable elements by adding ultrapure «carbon black», hence significantly more favorable situation with raw material,

- possibility of «regeneration» of the former in the use of tertiary slag with the help of the proposed according to the invention, recovery, prevention education is extremely expensive waste dumps, recycling of valuable alloying components such as Ni, Cr, V, W, Mo, TA and such,

- there is no education bridges loaded in the reactor, as he sucked in a graphite layer; (this is a big problem in the manufacture of electric furnaces: «education caps» from unevenly molten material),

- continuous, very economical process of melting, the small volume of the reactor (electric furnace works in batch mode),

- no problems with refractory material, as there has not been any contact slag with refractory material in the induction zone,

- high efficiency conversion of electrical energy into heat, very low thermal losses in comparison with electrode furnaces,

in minimal quantities of waste gases, suction gas preferably inert noble gas such as argon or nitrogen or reactive gases preferably F 2 , but also H 2 O, Cl 2 , O 2, or their mixture.

Figure 2 also shows the reactor is 1, which contains the graphite column 16. Unlike the reactor is shown in figure 1, in this reactor in the axial region provides a restful area, established in the form of zone 18, which due to the continuous increase cross-section of the reactor in the direction of the exhaust end results in a decrease in the velocity of the gas. This helps to and removed from the gas phase partially contained in suspension recovered particles melt by reducing affecting them shifting forces. The position 19 in the reactor marked fire-resistant layer, which serves as a reference vault for lying over him graphite bodies or lying above it graphite backfill. In the field of refractory layer 19 cross-section of the exhaust end again decreases, whereupon agglomerated particles melt closer to each other, stimulating further agglomeration.

Figure 3 reactor also indicated position 1, and the position of the 20 identified a reservoir or tank, which contains recoverable raw materials. Through a rotary shutter 21 various source materials may adjustable fed into the mixer 22, from which a mixture of original material through another lock shutter 23 and conveying device 24 may be submitted to the feed chute 6 reactor 1. At the outlet end of the reactor waste and melt metal available, and the hot waste gases are served in the heat exchanger 25, in which water is supplied. In a heat exchanger in the result of conversion of water gas is formed high-quality recovery or flammable gas containing carbon monoxide and hydrogen. Also it is possible to turn the still existing Zn-pairs in ZnO with the formation of hydrogen by adding water/steam. Generated gaseous waste is sent to the dust collector 26, in which precipitates may still present a secondary dust, so that through the exhaust manifold 27, e.g. furnaces for the production of clinker or replacement of the furnace can be fed clean combustible gas. Through a rotary shutter 28 secondary dust can be discharged from the dust collector.

Figure 4 rotary valve for dust loading source materials identified by the position of the 29, and dust source materials can be fed into the reactor 1 together with the holders of carbon that can be in solid or liquid form. Rotary shutter 29 opens in the supply pipe 30, which runs via housing 3 reactor 1. Supply pipe 30 seeks to set with the possibility of rotation takes the form of the fungus distribution body 31, which figure 4 shows a cutaway. It is seen that the distribution body 31 are grooves 32, which capture the supplied dust source materials, and in which a dust source materials sent down in the direction of graphite filling 16. Depending on the speed of rotation of the distribution of body 31 dust thrown onto a different distance from the center of the reactor 1 at the periphery of the reactor is 1, so that the profile of the applied layer of source materials on a graphite backfilling can be adjusted in a simple way.

Figure 5 position 33 identifies two sluice shutter, through which you can deliver relatively large amount of dust source materials on a graphite backfill 16. Position 34 the marked downward risers, which at a suitable angle directed on the surface of graphite filling 16. Position 35 marked-based body, which if necessary can be heated to obtain the optimum temperature of graphite filling 16. In the area of the hole 12 superseding the body of 35 supports graphite backfill and due to periodical fluctuations of the displacing body 35 can optimize issue, and at the same time is loosening graphite filling 16 and, if necessary, formed a congestion area graphite filling 16 again become a through.

1. Method for processing of solid or molten substances and/or , in particular, of light fractions, formed during their grinding, characterized in that substance for processing load on, at least partially, inductively heated graphite body, enter reducers, other than carbon graphite, and collect flowing restored and/or melt, and reducing agents are administered together with solid or melted downloadable substances, and as the reducing use natural gas, coal dust, dust brown coal, hydrocarbons, hydrogen, carbon monoxide and/or ammonia introduced together with water vapor, oxygen, carbon dioxide and/or Halogens or .

2. The method according to claim 1, characterized in that the graphite gasket body formed layer, column or filling of bulk graphite.

3. The method according to claim 1, characterized in that the graphite gasket body has a shape of graphite block with penetrating channels, apertures.

4. The method of claim 2, which regulate the pressure gradient on the axial length of the graphite backfill to suck in a graphite layer of solid or molten substances and reducers, other than carbon graphite, and if necessary, solid or molten downloadable substances.

5. The method according to claim 1, characterized in that as a reducing agent is injected coal dust or dust brown coal.

6. The method according to claim 1, characterized in that the solid reducing agents injected with a carrier gas, in particular, nitrogen, argon, CO, so 2 , O 2 or air.

7. The method according to claim 1, characterized in that the redox potential of graphite body regulate the introduction of the gas and the temperature of the graphite body adjust change of electric power consumption and with the help of introduction of gas.

8. The method according to claim 1, characterized in that the temperature and/or power consumption located one by one axis sections graphite body is measured separately, and temperature and oxidation-reduction mode in separate sections regulate by means of a regulation for electric power and/or subject to the introduction of gases and/or volume of injected gas.

9. The method according to claim 1, characterized in that glass particles or glass melts load on the heated up to red graphite body.

10. The method according to claim 1, characterized in that the graphite gasket body uses in the form of beads, cylinders, blocks, granulated molded bodies and/or scrap electrodes.

11. The method according to claim 1, characterized in that the graphite gasket body formed graphite and catalyst powder.

12. The method according to claim 1, characterized in that the graphite gasket body for regulation of the electric conductivity of compacted with relevant salts and/or metals or ceramics.

13. The method according to claim 1, characterized in that the graphite gasket body get with the regulation of its micro-porosity.

14. The method according to claim 1, characterized in that the induction heating is carried out by the power supply with two different frequencies.

15. The method according to paragraph 14, wherein one of two different frequencies lies in the range from 3 to 15 kHz, and the other frequency is below 0.5 kHz.

16. The method according to claim 1, characterized in that the graphite gasket body load in the form of filling of graphite with inert attachment bodies, in particular, the catalytically active bodies of the Cao or MgO.

17. The method according to claim 1, characterized in that, along with downloadable substances download dust in the steel industry for linking sulfur (S).

18. The method according to claim 1, characterized in that pyrophoric alloys formed crushed old tires containing oil scale of rolling production, RSW (polychlorinated biphenyls), contaminated used wood contaminated with spoil material (dioxins or furans), the remnants of the distillation of oil and dried sludge.