MXPA99005986A - Environmentally stable products derived from the remediation of contaminated sediments and soils - Google Patents

Abstract

This invention relates to thermo-chemical remediation and decontamination of sediments and soils contaminated with organic contaminants as well as inorganic materials with subsequent beneficial reuse. Novel environmentally stable products of commercial value are produced when certain additives such as calcium and metal oxides are mixed with the contaminated materials. In the process, the mixture is heated to 1150°C~1500°C to produce a molten reaction product with at least part of an excess amount of oxygen mixture or air is continuously bubbled through the melt in order to provide mixing and achieve high thermal destruction and removal efficiencies of the organic contaminants. The melt is then quickly quenched in moist air, steam, or water to avoid the transformation of the amorphous material into crystals. The inorganic contaminants such as chromium, nickel, zinc, etc. are incorporated and completely immobilized within the amorphous silicate network. Atmospheric emissions resulting from this process are nontoxic and capable of meeting currently specified health and environmental requirements. The amorphous material can be pulverized to yield a powder which evinces cementitious properties either by reaction with alkali solution or by blending it with other materials to produce blended cements. The compressive strengths of the concretes made from the powder of the subject invention and blends thereof are comparable to, or greater than the ASTM requirements for general purpose concrete applications. The powder of the subject invention, blended cements, and concrete/mortar derived therefrom also easily pass the EPA TCLP leach test to achieve environmental acceptability.

Description

PRODUCTS STABLE TO THE ENVIRONMENT DERIVED FROM THE REPAIR OF SEDIMENTS AND CONTAMINATED SOILS DESCRIPTION Background and field of the invention This invention relates to the repair and elimination of contaminants by thermochemical means of sediments and soils contaminated with different organic and inorganic compounds. New, environmentally stable products are generated along with the repair process when additives such as calcium and metal oxides are added to the contaminated materials.

All kinds of materials contaminated by the hand of man and that contaminate our environment are generated around the world. These pollutants are found in air, water, river sediments, synthetic coal gas factories, etc. There are two general types of contaminants: organic and inorganic. The most prevalent organic pollutants associated with sediments and soils include: polynuclear aromatic hydrocarbons (PAHs), hydrocarbons treated with chlorine such as polychlorinated biphenyls (PCBs), dioxins, furans, etc., and fossil fuel derived from hydrocarbons and their derivatives. The most common inorganic contaminants include volatile and non-volatile heavy metals and materials derived from minerals such as asbestos. Current thermal methods for the treatment of the above waste materials include the following four treatment systems: vitrification, plasma processing, molten metal processing and steam repair. None of these methods has been sufficiently proven to be cheap for large-scale decontamination applications. In addition, after treatment, these technologies generate large secondary waste streams that require expensive protection. This invention describes a new thermochemical transformation of sediments and contaminated soils into useful products for general construction applications, specifically, mixed cements and in this way can significantly improve the economy repair by creating such final value-added products. The main benefit of the present invention is to provide a cheap method for the repair of sediments and soils contaminated with both organic and inorganic contaminants by means of: a) ensure great thermal destruction (99.99% or more) of organic contaminants present in sediments and soils, converting contaminants into non-harmful compounds, such as C02, H20 and CaCl2; b) provide a process for incorporating and immobilizing inorganic contaminants such as heavy metals in an amorphous network of leachate-resistant silicates (mortar washing); c) transform contaminated sediments and soils into useful construction products. Another advantage of the invention is the ability to impart desirable specific reactivity properties to decontaminated sediments and soils by reaction with appropriate amounts of limestone, alumina, ferric oxides and fluxing agents during the melting stage in the presence of excess oxygen or gas that contains oxygen. A further advantage of the invention is a new waste management treatment technology to replace filling and incineration methods. These, and other benefits and advantages, are included in the invention which refers to a new process for the repair of harmful materials comprising sediments and soils that are contaminated by organic contaminants such as PAHs, PCBs, dioxins, furans, etc., and inorganic contaminants such as volatile and non-volatile heavy metals. Organic pollutants are volatilized from sediments and contaminated soils due to the high temperatures, 1150 ° C to 1500 ° C, found in the present process. The volatilized organic pollutants are thermally destroyed with destruction and removal efficiencies exceeding 99.99 percent by reaction with the excess oxygen present in the reaction chamber. The sediments and poor soils of organic pollutants then react additionally with adequate amounts of limestone, alumina, ferric oxides and other suitable additives that are added to the contaminated mixture to produce an amorphous molten reaction product within which inorganic contaminants and heavy metal cations such as lead, cadmium, arsenic, barium, chromium, mercury, selenium, silver, etc. in the form of their stable oxides they are incorporated and immobilized in the silicate network. The molten reaction product is rapidly cooled in moist air, steam or water to room temperature to prevent the transformation of the amorphous material into crystals and thus increase the chances that the heavy metal cations are incorporated into the amorphous non-crystalline material. The rapidly cooled fusion is then pulverized to produce the reactive melt of the present invention. Thus, the process of the present invention includes the repair and removal by thermochemical means of pollutants from sediments and soils contaminated with organic contaminants as well as with inorganic contaminants and comprises the steps of: combining the sediments or contaminated soils with a mixture of oxide source of calcium, alumina, ferric oxides and fluxing agents; heating the mixture to produce a molten reaction product; bubbling oxygen through the molten (molten) mass to destroy organic contaminants; rapidly cooling the melt in the presence of moist air, steam or water to form an amorphous material; pulverize the amorphous material to form a powder; and mix the powder with a cement to obtain a mixed cement. The product of the present invention comprises the reactive melt product of claim 2, further including magnesia (MgO), alkali (Na20 and K20), sulfur trioxide (S03) present as gypsum, phosphorus oxide (P205), titanium (Ti02) and strontium oxide (SrO).

Description of the Drawings Figure 1 is an X-ray diffraction graph of the present invention. Figure 2 is a graph of X-ray diffraction of the sediment from which the reactive melt of Figure 1 is prepared. Figure 3 is an X-ray diffraction graph of commercial portland cement. Figure 4 is an X-ray diffraction graph of a mixed cement produced from 40% by weight of reactive melt and 60% by weight of portland type I cement. Figure 5 is a graph of X-ray diffraction of a mixed cement produced from 70% by weight of reactive melt and 30% by weight portland cement type I. Figure 6 is a graph of light scattering X of a commercial portland cement mortar. Figure 7 is an X-ray diffraction graph of mixed cement mortar. Figure 8 is a schematic view showing the manufacture of the reactive melt by means of the present invention using a cupola furnace. Figure 9 is a schematic view showing the manufacture of the reactive melt by means of the present invention using a melting furnace heated by means of natural gas.

Figure 10 is a schematic view showing the manufacture of the reactive melt by means of the it will form a powder; and mixing the powder with a cement to produce a mixed cement. An exemplary reaction melt can be found when a repaired sediment (Table 1) through the process contains about 20 to about 40 weight percent lime (CaO), about 45 to about 65 weight percent silica (SiO2), approximately 5 to about 20 weight percent alumina (AI2O3), about 2 to about 10 weight percent ferric oxide (Fe203), about 0.1 to about 5 weight percent sulfur trioxide (SO3) present as gypsum , about 1 to about 3 weight percent magnesia (MgO), about 0.1 to about 5 weight percent alkalis (Na20 and K20), and about 0 to 5 weight percent fluxing agent. the properties of the resulting reactive melt by combining it with a portland cement. The amorphous nature of the reactive melt has been confirmed using an optical microscope with transmitted light or by subjecting it to the X-ray diffraction (XRD) technique to verify the composition of this product (Figure 1). Figure 1 shows no peak that could indicate the presence of crystalline structures. It is completely different from the XRD pattern from either the original contaminated sediments (figure 2) with larger peaks of quartz, chlorite, illite and mica (as indicated in the figure), or commercial portland cement with higher peaks of C2S, C3S and alite as shown in figure 3, or mixed cements (mixtures 40:60 and 70:30 weight percent reactive melt and portland cement) with smaller peaks_some due to the dilution of the Portland cement component by the melt amorphous reagent (figures 4 and 5 respectively). A product (reagent melt) thus formed when a sediment or soil has been repaired (primary elemental oxide mineral component of sediment samples from Newtown Creek of New York and an Illinois Superfund site soil are shown in Table 1) It is reactive in nature and its chemical composition can generally be established as Calcium oxide (CaO) 20 to 40% by weight Silica (Si02) 45 to 65% by weight Alumina (A1203) 5 to 20% by weight Ferric oxide (Fe203) 2 to 10% by weight Flux agent 0 to 5% by weight weight TABLE 1 MAIN SEDIMENT MINERAL COMPOSITION Another minor chemical composition of the reactive melt includes magnesia (MgO), alkalis (Na2? And K20), sulfur trioxide (S03) present as gypsum, halogens present as halogenated inorganics, phosphorus oxide (P2O5), titanium oxide (Ti02), strontium oxide (SrO), etc. and heavy metals. The melting point of the reactive melt bonded by means of the above chemical composition is between the temperatures of about 1150 ° C to about 1400 ° C. The crushed reactive melt demonstrates cementing properties either by reaction with aqueous alkaline solution (example I) or by mixing with materials such as portland cement (Examples II and III). The proportion by weight of reactive melt to portland cement for the production of mixed cements construction grade varies from 10 parts of reactive melt for 90 parts of portland cement to 70 parts of reactive melt for 30 parts of portland cement. In the molten phase, the silica (SiO2) by itself and in chemical combination with other oxides such as alumina (A120), ferric oxide (Fe203), sodium oxide (Na2?), Lime (CaO) etc. forms a silicate network that incorporates heavy metal atoms. The amount of a specified metal-weight that can be incorporated into the silicate network depends on the affinity of that heavy metal with other atoms present in the network. The elementary substitution can be estimated by comparing "ion replacement rates" calculated from the electrovalence, ionic radio, coordination number and electronic configuration of the cations (Jack Green, "Geochemical Table of the Elements," Bulletin of the Geological Society of America, Vol. 70, pp. 1127-1184, September 1959). The ion replacement rates of all the cations in question are present in table 2. TABLE 2 ION REPLACEMENT NECTS With reference to table 2, Ag +, Ba, Pb + 2 Sr. + "12" and Cd + 2 tend to be substituted by alkali metals; Hg + 2, Mn + 2, Zn + 2, Cu + 2 Sn + 2 and Ni + 2 tend to substitute Mg + 2 and Fe + 2; Cr + 3 tends to substitute Fe + 3; and so on. The rapid cooling of the melt causes distortion of the silicate network; at high cooling rates, the structure of the silicate network in the solidified melt becomes very irregular and its molecules solidify into non-crystalline, disordered glass. When the irregularity of the network is high, the opportunities for heavy metal cations to be incorporated that have different rates of ion replacement from other cations already present in the network are reinforced. The stability of the solidified melt depends on the strength of its silicate network structure within which the heavy metal impurities are incorporated. This resistance can be estimated by calculating the molar acidity of the melt, which is the molar ratio of the sum of the acid oxides of the melt to the sum of its basic oxides. In addition to silica, there are other common acid oxides in the melt A1203, IO2, Fe2? 3, P2O5, Cr2? 3 and Zr? 2,. The basic oxides common in the melt include CaO, MgO, Na20, K20, FeO, sulfur and chloride. If the molten acidity of the melt is high, the structure of the silicate network will be strong and the melt will be stable. For example, a typical portland Type I containing 21.3% by weight of SiO2, 5.3% by weight of Al2? 3, 2.3% by weight of Fe203, 65.2% by weight of CaO, 2.9% by weight of MgO and 3.0% by weight of S0 has a molar acidity of 0.33. A typical reactive melt has a molar acidity ranging from about 1.0 to about 2.5, so it is more stable to the environment than portland cement. Low-level leaching tests were used (by means of the Leaching Procedure characteristic of toxicity "Toxicity Characteristic Leaching Procedure, or TCLP) Anon. Analyt. Control, "TCLP: Improved Method," 12 (1), 1-6, ~~ publ. bu. ÑUS Corp., Pittsburgh, PA, 1987. to confirm findings of this invention. The results of the TCLP tests from reactive melt, mixed cement, portland cement and their mortar samples are presented in examples IV to VIII. To demonstrate the metal incorporation aspects of the present invention, chromium oxide was mixed (Cr2? 3) with the raw material used to produce both reactive and portland cement samples. These are discussed in examples IV and VI. The level of chromium in the reactive melt was determined to be approximately 1110 mg / kg (Table 5) and that of the portland cement was determined to be 307 mg / kg (Table 9). The leaching of each sample was determined by the test TCLP (adjusted in pH); The results are presented in Tables 6 and 10. Chromium leached from reactive melt at 0.94 mg / L. Chromium leached from portland cement at 11.8 mg / L, which is well above the TCLP control limit for 5 mg / L chromium. The comparison of the original chromium contents of each sample with its resulting leaching shows that the reactive melt is approximately 45 times less leachable than Portland cement. The mixed cement product made from reactive melt has the characteristic of rapidly consuming hydrated lime [Ca (OH)] present in the portland cement component of the mixed cement, when compared with the disappearance rate of the hydrated lime present in the conventional portland cement. This greatly improves the durability of the concrete or mortar prepared with mixed cement from reactive melt by essentially eliminating harmful side reactions, such as the reaction of alkali-silica (ASR). This is demonstrated and discussed in Example IX.

EXAMPLE I A portion of ground reactive melt was mixed with 2.75 parts of sand and 0.484 parts of 20 weight percent of aqueous NaOH solution to produce a mortar.

The mortar was placed as 5 cm (2 inch) cubes and cured under "wet conditions" at 55 ° C for 23 hours. After this, the samples were demolded and tested on compressive strength within one hour. A resistance of 21.4 Mpa (3100 psi) was reported as hydraulic activity of the reactive melt. This indicates that the reactive melt is reactive and cementitious in nature. The procedure and recipe for mortar preparation are part of a C-1073 standard of the ASTM (American Society for Testing and Materials.

EXAMPLE II Forty (40) weight percent of finely milled reactive melt (approximately 4000 cm2 / g) was mixed with sixty (60) by weight portland type I cement to meet the specifications of IP type mixed cement. / P according to the ASTM C-595 standard. It should be noted that no improved operating additives were added to the mixture. A portion of the mixed cement was mixed with 2.75 parts of sand and 0.484 parts of deionized water as prescribed in the ASTM C-109 procedure to produce mortars. The mortars were cast as 2 cm cubes and left overnight in a humid room at room temperature. After this, the cubes will be demolded and They cured in saturated lime-water solution. The compression strengths tested after 3, 1 and 28 days are comparable to, or superior to, the levels required by the ASTM The results presented in Table 3 are the averages of three separate tests of compressive strength.

TABLE 3 RESISTANCE TO COMPRESSION OF MIXED CEMENT IP / P TYPE PRODUCED FROM 40% IN REACTIVE CASTING WEIGHT AND 60% IN PORTLAND CEMENT STYLE TYPE I FLOOD REAGENT ASTM RANGE PERIOD IP / P TYPE: CEMENT FOR ASTM TYPE FOR TEST PORTLAND: 40: 60 IP / P TYPE I ** -Mpa (psi) 3 days 13.44 (1950; 12.5 (1810) 12.0 (1740) (for IP Type only) 7 days 18.82 (2730] 10.4-19.4 * 19.0 (2760) (1510-2810) 28 days 31.85 (4620; 20.7-24.2 * 28.0 (4060) (3000-3510) * The lowest values are ASTM requirements for type P; the highest values are for mixed type IP cements. ** For cross-comparison purposes, the strength requirement for general purpose portland type I cement has also been included in Table 3 of the ASTM C-150 standard (Tables 3 and 4).

EXAMPLE III The mortar cubes were prepared according to the procedure of Example II without adding any improved admixture of performance or performance except that seventy (70) weight percent of the finely ground reactive melt was mixed with thirty (30) weight percent. Type I portland cement to produce mixed and modified type P ~ cement. Type P is mixed cement for concrete construction where high early strength is not required. ASTM does not specify a 3-day compressive strength requirement for modified P-type mixed cement.

TABLE 4 RESISTANCE TO THE COMPRESSION OF MIXED C TYPE CEMENT MODIFIED, PRODUCED FROM 70% OF CAST REAGENT AND 30% OF PORTLAND CEMENT TYPE I r. FLOOD MODIFIED REAGENT PERIOD TYPE P: PORTLAND CEMENT: ASTM FOR TEST TYPE 70:30 P Mpa (psi) 3 days 6.21 (900) Not Specified 7 days 10.41 (1510) 10.4 (1510) 28 days 22.41 (3250) ~ 20.7 (3000) EXAMPLE IV - The metallic analysis of a crude dredged sediment and the reactive melt are presented in Table 5 and the results of the toxicity characteristic leaching procedure (TCLP) tests in the reactive melt are presented in Table 6. Metallic analysis of the reactive melt leachate indicated that most of the metals were retained in the silicate network of the reactive melt due to the reaction-melting stages of the process. Some metals such as arsenic and mercury are volatilized during the heat treatment and captured downstream in the required air pollution control devices.

TABLE 5 METALLIC ANALYSIS OF SEDIMENTO DRAGADO RAW AND CAST REAGENT SEDIMENTODRAGADO FUNDIDO REAGENT DOSIFICADO RAW COMPONENT WITH CHROME Arsenic 33 < 5 Barium 192 * Cadmium 37 < 5 Chrome 377 1110 Lead 617 130 Mercury 1.3 < 5 Selenium < 3.24 ** < 5 Silver 18 < 10 * Not analyzed ** - < indicates low analytical detection limit for the analyte TABLE 6 METAL ANALYSIS OF REAGENT CASTING LEACHING AND TCLP CONTROL LIMIT * < indicates below the analytical detection limit for the analyte EXAMPLE V Metallic analyzes were carried out according to the procedure of Example IV only that a mixed cement was used (reactive fused: portland cement = 40% in weight: 60% by weight) instead of the reactive melt. The results are presented in, table 7. The results of the leaching tests are presented in table 8.

TABLE 7 METALLIC ANALYSIS OF CRUDE DRAGED SEDIMENT AND MIXED CEMENT Not analyzed ** < indicates below the analytical detection limit for the analyte TABLE 8 METALLIC ANALYSIS OF LIXING OF MIXED CEMENT AND THE TCLP CONTROL LIMIT < indicates below the analytical detection limit for the analyte EXAMPLE VI The metal analyzes were carried out according to the procedure of Example IV only that a portland cement sample was used in place of the reactive melt. The Results are presented in Table 9. The results of the leaching tests are presented in Table 10.

TABLE 9 METALLIC ANALYSIS OF SEDIMENTO DRAGADO CRUDO AND CEMENT PORTLAND < indicates below the analytical detection limit for the analyte TABLE 10 METALLIC ANALYSIS OF PORTLAND CEMENT LIXING AND THE TCLP CONTROL LIMIT = < indicates below the analytical detection limit for the analyte EXAMPLE VII Representative samples of Portland cement mortar and mixed cement mortar were analyzed by means of the X-ray diffraction technique (XRD) to verify the composition of the compound. The results of the XRDs presented in Figures 6 and 7 compare the differences in the XRD patterns. Since the mortar is composed mainly of silica sand, many of the major peaks exhibited are due to quartz and similar crystals.

EXAMPLE VIII Metallic analyzes were carried out in accordance with the procedure of Example IV only that the sample of reactive melt mortar, that of portland cement mortar and that of mixed cement mortar were used.

TABLE 11 METAL ANALYSIS OF REAGENT CAST MORTAR SAMPLE AND PORTLAND CEMENT MORTAR SIGN < indicates below the analytical detection limit for the analyte TABLE 12 METALLIC ANALYSIS OF REAGENT CAST MORTAR LEAKS AND MORTAR OF PORTLAND CEMENT AGAINST THE TCLP CONTROL LIMIT * -: < indicates below. analytical detection limit for the analyte EXAMPLE IX The mixed cement product made from reactive melt has the characteristic of consuming hydrated lime quickly [Ca (OH) 2] present in the portland cement component of the mixed cement, when compared to the disappearance rate of the hydrated lime present in conventional portland cement. This significantly improves the durability of concrete or mortar prepared with mixed reactive melt cement essentially eliminating harmful side reactions, such as the alkali-silica reaction (ASR). In this example, the paste prepared from either mixed cement (from the reactive melt) or portland cement samples and water was analyzed by differential scanning calorimetry (DSC) to determine the disappearance of Ca (OH) 2 during the initial curing phases from 3 to 28 days. Other benefits and advantages of the present invention will be understood through the following detailed description and the accompanying process flow diagrams wherein: As stated, a process of the present invention involves introducing feedstocks such as sediments and soils contaminated, lime, metal oxides and fluxing agents containing chemical compounds necessary for the production of reactive melt in a melter in appropriate proportions. The most common source of lime is limestone which contains mainly calcium carbonate (CaCOs). When heated to approximately 900 ° C, this compound decomposes into lime (CaO) and carbon dioxide (C02), the latter, being a gas, normally escapes the process without affectation. Normally, the limestone is preheated before its introduction into the melter, not only for carbon dioxide ejection, but also to demand less energy in the melter. Other naturally occurring materials such as aragonite, gypsum, calcareous clay, clayey limestone, shale and sea shells are equally suitable for use as raw material for feeding in the process. The feedstock also includes a source of silica; Excellent sources of silica are sediments and contaminated soils. The silica source can be introduced into the melt as fines, at room temperature, but preferably preheated. The feedstock, in addition to including a source of lime and a source of silica, also includes a source of alumina, a source of ferric oxide and a source of a fluxing agent such as calcium fluoride, although the amount of such materials they are useful is considerably less than the amount of lime or silica. Other materials may appear in smaller quantities in the reactive melt as noted above and may also be present in the different raw materials. These include alkali compounds (sodium and potassium) and sulfur, titanium, magnesium, manganese, phosphorus, barium and strontium.

Within the melter, the raw material is combined and chemically reacted so that the melt formed, when removed and cooled rapidly, has appropriate proportions. Toxic metals such as lead and cadmium are incorporated and immobilized within the amorphous silicate network. The fusion, combination and reaction of the above feedstock for the manufacture of the reactive melt can be carried out with a specially constructed cupola furnace (Figure 8), a melting furnace heated by means of natural gas (Figure 9), an electric melting furnace (figure 10), or other fusion devices. A cupola 10 is a vertical and cylindrical vat furnace similar to a blast furnace and its main function is efficient fusion-conversion. The cupola 10 comprises a water-cooled cylindrical steel shell 12 coated with refractory materials, equipped with an air distribution conduit to the nozzles (wind cylinder, blow-air collector tube, not shown) and water-cooled nozzles 14 to provide supply and admission of air or oxygen mixtures in the tank. At least part of the air supply or oxygen mixture is continuously bubbled through the melting zone located at the bottom of cupola 10. They are provided loading doors in the upper levels and holes or discharge ports 18 near the bottom to allow the molten material to flow out. The zone of disappearance of oxygen in which the global reaction - C + 02? C02 is predominant, it is called oxidation zone or combustion zone. C + 02? C02? H = -94 kcal / mol The heat generated by the reaction in this area completes the fusion process. The temperature of the melting zone 16 is maintained at approximately 1150 ° C to 1500 ° C. The temperature of the combustion zone varies from below the melting temperature to approximately 1000 ° C. The melting temperature can vary depending mainly on the materials comprising the reactive melt. The combustion zone also provides from about 0.5 to about 4 seconds of residence time for the combustion gases to achieve great thermal destruction of the organic contaminants. Above the combustion zone is a heat transfer zone in which the limestone is broken down into quicklime at approximately 870 ° C to 1000 ° C. The Lime also acts as a filter to trap entrained particulates and heavy non-volatile metals from the melter's combustion gases. The heat transfer zone may comprise a separate piece of equipment, such as a vertical tank calcination furnace, if desired. Above the heat transfer zone is a preheating zone which may be a separate piece of equipment 28, in its upper region. A limestone load at approximately 870 ° C is heated in the preheating zone. The gases that leave leave the preheating zone at a temperature of approximately 250 ° C to approximately 350 ° C. Additional waste heat can be recovered from the gases left to remove excess moisture content in the sediments and soils before they are fed to the melter. The drying of the wet materials can be carried out in a separate piece of equipment (not shown in Figures 8, 9 and 10) at temperatures of about 55 ° C to 95 ° C to minimize the volatilization of chlorinated and other toxic compounds in the combustion gases. If necessary, the combustion gases can be bubbled before they are emitted into the atmosphere. ~~ One of the advantageous features of the previous process is that the counterflow backflow of the material Feeding becomes an inherent part of the fusion process. The hot gases that flow upwards come into intimate contact with the downward charge and allow a direct and efficient heat exchange to take place. Because of the emissions that arise from a cupola furnace furnace, in some places where air emission regulations are stricter, natural gas can be used as fuel to replace the coke in a natural gas-fused furnace. Another reason for using natural gas may be the result of ash contamination caused by the coke or coal used in the cupola. As shown in Fig. 9, a melting furnace heated by natural gas 30 consists of a cylindrical, vertical, water-cooled, refractory lined steel container 31 and a non-consumable, hollow steel lance 32. The furnace 30 is also it equips with power ports 34 and 35_ and gas outlet 35 in the upper levels and pouring hole 18 lightly on the bottom of the furnace. The outer surfaces of the furnace wall and the bottom are cooled by a stream of water flowing in the cooled jacket 36. Additive components (including alumina, bauxite, ferric oxide and fluxing agent) and quick lime are fed by gravity through the feed ports 34 and 35. The lance 32 injects natural gas (or fuel oil) and an excess amount of oxygen or air mixture into the container 30. The mechanism by means of which the melting is effected in the melting furnace is the heat released by the combustion of natural gas and oxygen: CH4 + 202 - C02 + 2H20? H = -192 kcal / mol A protective layer of solid slag 37 prevents the lance from being consumed. During normal operation, the tip of the lance is immersed in the molten bath 16 to provide the proper mixture and achieve high efficiency in destruction. thermal and elimination of organic pollutants. Alternatively, as shown in Figure 10, an electric melting furnace 40 can be used to achieve the same purpose. An electric melting furnace 40 continuously melts the raw material used for the manufacture of reactive melt and includes a furnace vessel 42 coated with refractory. A plurality of electrodes 44 extending into the furnace vessel from its side or upper part is illustrated schematically in Figure 10. Each of the electrodes 44 can move in the melting bath 16 or away from it in millimeter increments by means of a worm gear mechanism (not shown) to adjust to a certain depth of immersion. For high melting performance, the electric melting furnace is designed as a three phase alternating current furnace. The introduction of energy can be effected by heat of resistance. The immersion depths of the electrodes 44 are adjusted for constant performance, the electrodes being individually controlled. The heat from the electrodes 44 melts the feedstocks including the waste materials at a temperature of about 1150 ° C to 1500 ° C and the molten reactive melt of almost uniform composition is formed as a result of the liquid phase oxide reactions. . The molten reactive melt from a hotter region below the surface is continuously removed from the furnace vessel through the flushing device 26. It is preferred that the location of the flushing device be slightly above the bottom of the furnace vessel. The temperature range of the combustion zone in an electric melting furnace or a melting furnace heated by natural gas is similar to that of a cupola, starting from the melting temperature to approximately 1000 ° C. The residence time between approximately 0.5 to 4 seconds of the combustion gases generated in the heating stage is useful to allow high thermal destruction of organic contaminants in the combustion zone. As in the cupola, the reaction of limestone to quicklime can also be carried out in a separate piece of equipment 28 (for example a vertical tank calcination furnace). The hot gases coming from the combustion zone will provide the energy required for the decomposition of the limestone and the hot quick lime that is being loaded continuously in the melting furnace.

CaC03? C02 + CaO? H = 42. 82 kcal / mol The vertical lime kiln calcination furnace 28 can be heated by means of fuel oil or natural gas, if additional energy is required. The molten reactive melt is maintained through the exits 18 of the cupola; the electric melting furnace; or the melting furnace heated by natural gas generally at a temperature above about 1300 ° C. The melt is rapidly cooled in moist air, steam or water to prevent crystallization and to strengthen the incorporation of heavy metals. The melt Rapidly cooled is sprayed to produce the product, a reactive-melt, which can then be mixed with portland cement or other cements to produce mixed cements. The rapidly cooled melt can be sprayed to a particle size in the longest dimension of 1 to 100 microns, and preferably a particle size of 5 to 40 microns to obtain a faster setting of the resulting mixed cement. A contemplated process uses a feed material, without preprocessing requirements such as water removal and classified according to its size, of all types of contaminated sediments of estuarine, river, ocean, or lake and contaminated soils (sand, clay , or shale). Sediments and contaminated soils are fed either to the melting zone or the combustion zone of the kilns depending on the nature and type of the contaminants; where the sediments and soils poor in organic pollutants plus the appropriate quantities of lime, metal oxides and fluxing agent are incorporated into the melt and thus form the subsequent reactive melt. Due to the presence of calcium in the melt, HCl, chlorine or SOx could not be formed. Chlorine (if any) or chlorinated compounds, S0X, (if any) and the N0X in the combustion gases are typically bubbled or washed. Very volatile heavy metals such as mercury and arsenic can be removed from the exhaust gas by means of a simple in-line bag filter or activated carbon or silver or sulfur-impregnated activated carbon. The volatilized compounds of sodium, potassium and phosphorus in the exhaust gases are bubbled and eliminated. Non-volatile metals trapped in the flue gases are also bubbled and returned to the melting zone for subsequent incorporation into the present invention. All the suggested melting furnaces are well suited to use waste tires made of strips as waste feedstock and energy sources because these furnaces operate at very high temperatures and have long residence times. Furnace temperatures "typically exceed approximately 1300 ° C (2372 ° F) .High temperatures, long residence times and an adequate supply of oxygen ensure a complete burn of organics, which prevents the subsequent formation of dioxins" and furans, a very important consideration in the combustion of solid waste. In addition, the reactive melt production process of the present invention can utilize the iron contained in the steel cords and tire belts. Steel does not change the quality of the product Reactive melt, because large quantities of iron compound are already present as one of the main ingredients. In some cases, when insufficient ferric compound is present in the feedstocks, the iron contained in the tires with steel layers can help to improve the properties of the final reactive melt product. The sulfur contained in the tires reacts with the limestone to form gypsum which is also one of the ingredients required for the production of the reactive melt. This reaction also alleviates concerns about SOx air emissions from sulfur in rubber tires. In general, burning the waste tires in the furnace can improve the operation of the furnace, can reduce the requirements of natural gas and achieve more stable operation due to the greater volume of energy and the more uniform composition of the tires. When ash contamination is not a problem and air emission levels are adequately monitored, waste tires made of strips can be added to the feed materials to reduce the consumption of fuel and electrical energy. This can be important when the feed is wet as in the case of estuarine sediments.

Although the invention has been described with reference to a preferred embodiment, it should be understood by those of ordinary skill in the art that several changes can be made and equivalents can be substituted for their elements without departing from the scope of the invention. In addition, many modifications can be made to adapt to a particular situation or material to that described in the present invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the embodiments described as the best ways to carry out this invention, but that the invention includes all modalities and equivalents that fall within the scope of the appended claims. Several features of the invention are set forth in the following claims.

Claims (11)

1 A product stable to the environment of a process for the repair and decontamination by thermochemical means of sediments and soils contaminated with organic materials as well as with inorganic contaminants and heavy metals, the process includes the steps of: a) mixing the contaminated sediments or soils with a source of calcium oxide, alumina, ferric oxides and fluxing agent to form a mixture; b) heating the mixture to produce a molten reaction product; c) bubbling oxygen through the reaction product to destroy the organic contaminants; d) rapidly cooling the reaction product in the presence of moist air, steam or water to form an amorphous material having a silicate network, and thereby incorporating inorganic contaminants and heavy metals into the silicate network; e) pulverizing the amorphous material to form a powder; f) mix the powder with cement to obtain a mixed cement.

2. The product according to claim 1, characterized in that the fluxing agent is calcium fluoride.

3. A reactive molten product which is amorphous and has the composition of: calcium oxide (CaO), approximately • 20 to 40% by weight; silica (SiO2), about 45 to 65% by weight; alumina (A1203), about 5 to 20% by weight; ferric oxide (Fe203), approximately 2 to 10% in-weight; and fluxing agent, about 0 to 5% by weight.

4. The reactive molten product according to claim 3, further characterized in that it also includes minor chemical components of magnesia (MgO), alkalis (Na20 and K20), sulfur trioxide (S03) present as gypsum, halogens present as halogenated inorganics, phosphorus oxide (P205), titanium oxide (Ti02) and strontium oxide (SrO).

5. The reactive melt product according to claim 3, further characterized in that the melting point of the reactive melt is between the temperatures of about 1150 ° C to about 1400 ° C.

6. The reactive melt product according to claim 3, further characterized in that it is mixed with 2.75 parts of sand and 0.484 parts of 20% by weight of aqueous NaOH solution per part of the reactive melt product, to produce a mortar with a compressive strength greater than 21.4 MPa.

7. The reactive melt product according to claim 3, further characterized in that it is also mixed with portland cement to produce a mixed cement.

8. The reactive molten product according to claim 3, further characterized in that the heavy metals are incorporated into a silicate network within the reactive molten product.

9. A mixed cement comprising a mixture of portland cement and a reactive molten product, the reactive molten product includes CaO, SiO2, AI2O3, Fe203 and CaF2, the weight ratio of reactive molten product to portland cement being about 10 parts of molten product reactive to approximately 90 parts of portland cement up to about 70 parts of reactive molten product to approximately 30 parts of portland cement.

10. The mixed cement according to claim 9, further characterized in that the reactive melt component consumes hydrated lime present in the portland cement.

11. The mixed cement according to claim 9, further characterized in that the reactive molten product has the composition of: calcium oxide (CaO), approximately 20 to 40% by weight; silica (Si02), approximately 45 to 65% by weight; alumina (A1203), about 5 to 20% by weight; ferric oxide (Fe203), about 2 to 10% by weight; and fluxing agent, about 0 to 5% by weight. SUMMARY This invention relates to the repair or decontamination by thermochemical means of sediments and soils contaminated with organic contaminants as well as with inorganic materials with a subsequent beneficial reuse. New environmentally stable products of commercial value are produced when certain additives such as calcium and metal oxides are mixed with the contaminated materials. During the process, the mixture is heated to 1150 ° C ~ 1500 ° C to produce a molten reaction product with at least part of an excess amount of oxygen or air mixture being continuously bubbled through the melt in order to produce a mix and achieve great efficiency of thermal destruction and elimination of organic pollutants. The molten mass is then rapidly cooled in moist air, steam, or water to prevent "transformation of the amorphous material into crystals." Inorganic contaminants such as chromium, nickel, zinc, etc. are incorporated and immobilized completely within the amorphous network. The atmospheric emissions resulting from this process are not harmful and are able to meet the current environmental and health requirements specified. The amorphous material can be pulverized to produce a powder thatshows cementing properties either by reaction with alkaline solution or by mixing with other materials to produce mixed cements. The compressive strengths of the concretes made from the powder of the present invention and their blends are comparable to or superior to the requirements of the ASTM for general purpose concrete applications. The powder of the present invention, the mixed cements, and the concrete / mortar also derived therefrom easily pass the TCLP leaching tests from the EPA achieving environmental acceptability.