MXPA93005689A - Procedure for the preparation of dispersions of solid, homogeneous, fine materials in the form of dust and containing eventually substances acti - Google Patents

Abstract

For the preparation of a homogeneous, fine dispersion and in the form of a powder of solid materials, a suspension of solid materials containing water is homogenized with the reaction product which consumes water, for example calcium oxide, aluminum alcoholate, silicic acid ester or its mixtures In this case, the reaction that consumes water leads to a solid reaction product. For homogenous loading of the resulting solid material dispersion with active substances, a homogeneous mixture is homogenized on the basis of the suspension of solid materials containing water and a finely dispersed solution or suspension of the active substances with the reactant of a water-consuming reaction. . Dispersions of solid materials, possibly loaded with active substances, can be used in multiple ways depending on the components used, in the agricultural sector and in technical processes, in particular also in the protection of the environment.

Description

PROCEDURE FOR THE PREPARATION OF DISPERSIONS OF SOLID, HOMOGENEOUS, FINE IN THE FORM OF POWDER MATERIALS AND WHICH CONTAIN EVENTUALLY ACTIVE SUBSTANCES INVENTOR: FRIEDRICH BOLSING, Danish citizen, residing at Danziger StraBe 5, Lindhorst, Denmark D-3067. CAUSAHIENT: DCR INTERNATIONAL ENV IRONMENTAL SERVICES, INC., A Japanese company, domiciled at 17-7 Todoroki 5-chome Setagaya-ku, Tokyo 158, Japan.

EXTRACT For the preparation of a homogeneous dispersion, fine and in powder form of solid materials is homogenized # a suspension of solid materials containing water with the educt of a water-consuming reaction, for example calcium oxide, aluminum alcoholate, silicic acid ester or mixtures thereof. In this case, the reaction that consumes water leads to a solid reaction product. For homogenous loading of the resulting solid material dispersion with active substances, it is homogenised * a homogeneous mixture based on the suspension of solid materials containing water and a finely dispersed solution or suspension of the active substances with the reactant of a water-consuming reaction. Dispersions of solid materials, possibly charged with active substances, can be used in many ways depending on the components used, in the agricultural sector and in technical processes, in particular also in the protection of the environment.

The dispersions of solid materials play an important role in the agricultural sector and in the technique. Examples of these are fine clay powders, which play an important role as soil improvement agents as well as adsorption agents in industrial processes. When dispersions of finely dispersed solid materials are to be prepared from finely dispersed precursor products, containing water, for example from natural clay, thermally expensive drying processes are necessary with subsequent mechanical homogenization. When dispersions of finely dispersed solid materials are to be prepared from solid materials or coarse-grained solid material components, ST requires mechanically expensive grinding or grinding processes in order to obtain dispersions of materials * solids that are widely dispersed and homogeneous; in addition to these mechanical processes, limits have been established due to the fact that the size of grains that can be achieved in this case in a specific way for a material is determined only by the shear forces that can be achieved at the most technical scale . The object of the invention is therefore to provide a method by which dispersions of extremely homogeneous and finely dispersed solid materials can be prepared without any special technical expense. To solve the problem posed by this mission, a suspension of finely dispersed solid materials, containing water, is homogenized by mechanical means with a reactant of a chemical reaction that consumes water, for example with an alkaline earth metal oxide or an alcoholate. of aluminum or with a silicic acid ester, or with a mixture of these compounds, and then the homogenized material is allowed to react completely, and the stoichiometric amount of water required is consumed. As a water-consuming reaction, the reactions are chosen in which, from the starting material, a ^^ finely dispersed solid material; correspondingly, hydroxides of alsalino-earth metals or aluminum hydroxides or silicic acid are formed from said educts. Suspensions of finely dispersed, water-containing solid materials useful for the purposes of the invention are suspensions of finely dispersed solid materials and water. Finely dispersed materials in the sense of the invention are materials having particle sizes in the range of >; 0 up to < 250 micrometers, preferably in the range of 1 to 50 micrometers which, due to their structural characteristics, have a good adsorption capacity. Examples are layered silicates, finely dispersed silicic acid, aluminum oxides and hydroxides d? aluminum, precipitated clay and iron oxides. Their pasty mixtures with water are designated in the present case as suspensions of finely dispersed solid materials. The proportion of water in the suspension of finely dispersed solid materials can fluctuate within wide limits, provided that, on the one hand, a sufficient quantity of water is present for the subsequent chemical reaction with an alkaline-earth metal oxide or an alcoholate. of aluminum, and provided, on the other hand, that water is no longer present as is permissible for the preparation * tion of a dispersion of solid materials in powder form. Preferably, the water content of the suspension of finely dispersed solid materials is adjusted in such a way that a doughy, doughy mass is present. Suspensions of finely dispersed solid materials, containing water, may be of natural or industrial origin. A suspension of finely dispersed solid materials, containing water and is pasty and arable, of natural origin is clay, such as is obtained in deposits for the manufacture of porous ceramic materials, and which can be used according to the invention in an unaltered state. The fuller's earth and fine clay powders are of industrial origin; if they are mixed with water, ST obtains suspensions of finely dispersed solid materials containing water, which are also useful in the sense of the invention. In addition to clay, clay-type and clay-containing materials can also be used for the preparation of suspensions of finely dispersed solid materials containing water. When in this context we are talking about clay-type and clay-containing materials, this refers only to BU adsorption capacity by virtue of physical structural characteristics and not chemical composition. Examples are fr flying powders, fine filter dust, ash and production residues containing clay or clay type, for example production residues from the food industry in the form of spent fuller lands or, for example, red muds , which is a pasty mass predominantly based on iron oxides and iron hydroxides, which is formed in connection with the production of aluminum. It is part of the essence of the invention that the water contained in the suspension of finely dispersed solid materials is consumed uniformly in the chemical reaction with an alkaline earth metal oxide or an aluminum alcoholate, since only under this premise can it be form a dispersion of solid materials in the form d? powder and homogeneous. For this reason, the reaction that consumes water can only be initiated when the water-consuming reaction oil has been evenly distributed in the suspension of solid materials. This can be achieved if either the suspension of finely dispersed solid materials, containing water, is homogenized so rapidly with the reactant of the water-consuming reaction, that the latter is evenly distributed therein, before it begins to spread. noteworthy is the chemical reaction that consumes water, or by the fact that known reaction retarders are added to the suspension of finely dispersed solid materials containing water, eg a solution of ammonia, alcohols, sulphates of alkali metals and similar materials, or if the reaction product which consumes water, for example with an alcohol or with long chain amines, fatty acids and similar compounds is treated in a corresponding manner. Instead of the pure educts, alkaline earth metal oxide or aluminum alcoholate or silicic acid ester, mixtures of alkaline earth metal oxides or aluminum alcoholates or silicic acid esters or mixtures of these classes can also be used. of compounds. The clay products obtained according to the invention can be used as soil improvement agents or as building material in soil, for example for the sealing of waste landfills. This is valid in the appropriate sense for other suspensions of solid materials of the mentioned ones. Dispersions of solid materials with aluminum hydroxide or silicic acid can serve as effective adsorption agents. Numerous chemical and physical properties of the active substances on a solid support material advantageously vary according to their degree of dispersion. As a rule, the chemical reactivity increases the more finely divided a solid or liquid material is present as a participant in a reaction on a support material. In the physical aspect, for example, there is a variation in the speed with which equilibria are adjusted, for example, in response to adsorption or dissolution processes. With finely divided active substances on a solid support material, chemical and physical processes are possible, which otherwise do not occur or only proceed very slowly. As is known, solid and liquid active substances can be applied by milling by mechanical means on a solid support material. It is also possible to impregnate a solid support material with a solution of an active substance and then dry the suspension. Suitable active substances can be applied from the vapor phase onto solid support material. Finally, there is the possibility of transferring active substances in the course of a chemical reaction that produces dispersion, in a homogeneous and finely dispersed manner, to a solid support material. The aforementioned procedures are subject, in terms of their applicability, to certain limitations or have other disadvantages. Thus, limits to the grinding of active substances are established in that the shear forces that can be achieved by mechanical means are not sufficient to achieve a very thin distribution of the active substances in the grinding material. The preparation of dispersions of solid materials in the form of powders, homogeneously charged, with the use of a solution of active substances or by application from the vapor phase is limited to soluble or evaporable active substances and, because of the necessary technical expense, as a rule also it's expensive The very fine homogeneous distribution of active substances in the course of chemical reactions in which dispersion is effected is limited to active substances which can be pre-distributed in the product of the chemical reaction in which a dispersion is effected. Added to this is the fact that these educts, that is, the alkaline-earth metal oxides, the aluminum alcoholates and the silica esters are relatively expensive. The invention therefore also has the task of preparing dispersions of solid materials in the form of powders, homogeneously loaded with active substances, in a technically simple way and therefore also cost-effective and avoiding limitations and disadvantages. In order to solve the problem posed by this task, a suspension of finely dispersed solid materials containing water is homogenized mechanically with active substances or mixtures of active substances, and the homogenized material is then homogenized with an alkaline earth metal oxide or a aluminum alcoholate. According to the idea of the invention, the adsorption capacity present latently of the solid materials which are present in a finely dispersed state in a suspension of solid materials containing water, which solid materials are completely covered with water in this environment and therefore not are practically capable of adsorption, it is useful if the water of the suspension of solid materials containing water is chemically subtracted, in the presence of adsorbable active substances, present in a homogeneously distributed state, which can be presented in the form of a solution of a finely dispersed suspension, by means of a water-consuming reaction, for example by the hydration reaction of an alkaline earth metal oxide or by the hydrolysis of an aluminum alcoholate, in such a way that the active substances are fixed by adsorption to the surface of the solid material that is now widely anh idro. The fact that the solid reaction product belongs to the essence of the invention, finely dispersed, which is formed at the same time from the starting material of a reaction which consumes water, for example a hydroxide of an alkaline-earth metal or finely dispersed aluminum from an oxide of an alsaline-earth metal or from a aluminum alcoholate, in this case also becomes active for adsorption. The advantage of the invention is based on the fact that, unlike a mechanical dispersion operation, also small amounts of active substances are distributed homogeneously on a solid support material and that, unlike a very homogeneous distribution of homogeneous active substances in the course of chemical reactions in which dispersion takes place, the premise in that indispensable case is not necessary at all, that is to say, the previous distribution capacity of the active substances that are to be distributed in the reactant of the reaction chemical in which a dispersion is effected, for example in an alkaline earth metal oxide, an aluminum alcoholate or a silicic acid ester. Entirely to the contrary, according to the invention, for the preparation of a dispersion of solid materials in powder form, homogeneously charged with active substances, the active substance is mechanically homogenized with a suspension of finely dispersed solid materials, containing water, and the homogenous material is then homogenized only with an alkaline earth metal oxide or an aluminum alloy. In this way, the proportion of alkaline earth metal oxide or aluminum alcoholate oxide can be considerably reduced, which is necessary for the preparation of a dispersion of solid materials in powder form, homogeneously charged, and can be reduced in favorable cases up to approximately one tenth of the amount necessary for a chemical reaction in which a dispersion is effected. As active substances, in the present case substances are designated which, in contrast to the substances of the suspension of solid materials which are merely considered as support material, are especially active in their finely divided state in the chemical and physical aspects . In this context, too, it is not about the physical and chemical properties of the participating materials, but only about the role assigned to them for the respective purpose of use. This has to be explained with the help of two examples. The natural clay is homogenized by kneading with a concentrated aqueous solution of sodium sulfide; the resulting plastic mass provides a dispersion of solid materials in the form of powder homogenously charged with sulfide ions in the subsequent chemical reaction which consumes water with approximately 15% hydrophobic calcium oxide, based on the amount of clay used. The finely divided active substance constituted by sulfur ions constitutes, as is known, a precipitation reagent with a high reactivity, with which it can be transformed * numerous toxic heavy metals, by precipitation, in heavy metal sulphides that are insoluble in water and thus can fix and chemically immobilize. For this purpose, soils, fly ash and slag contaminated with heavy metals are mixed with the aforementioned dispersion of solid materials and then consolidates to form a body of solid material. Contaminated materials in the form of coarse pieces, for example coatings of chimneys, parts of foundations, apparatuses, utensils and the like, are embedded in said dispersion of solid materials as such, or in admixture with other materials advantageous from the point of sight of soil mechanics, producing a consolidation. The aspect of soil mechanics plays an especially important role in the case of the treatment of metal-clarifying and purification sludges contaminated by metals ? heavy, with its gel structures unstable from the point of view of soil mechanics, after homogenization with the aforementioned dispersion of solid materials, can deposit them safely in the form of a stable solid phase and capable of support from the point of view of soil mechanics. In this case, it is particularly advantageous in the economic sense to incorporate in suitable mixture waste materials, for example slags and ashes, which are contaminated with heavy metals. According to a particularly effective variant of the process, a partial amount of the clay is first mixed with an aqueous solution of an alkali metal sulphide and then a second partial quantity is kneaded with an aqueous fine-grained suspension of iron sulphate. If both partial amounts are then homogenised, finely divided iron sulphide is formed in situ, which is embedded in the clay structure. The mass that remains pasty is then reacted chemically with approximately 20%, based on the total amount of clay, d? a normal calcium oxide, that is, not hydrofuged. The stoichiometric quantitative ratios are chosen such that a small excess of iron ions, for example 10%, is present. Next, the active substance consists of iron sulfide that is considered to be insoluble in water. Because of the much lower solubility product of the toxic heavy metal sulphides, however, reprecipitation is carried out after its incorporation in a mixture with materials contaminated by heavy metals. In this way, an especially effective immobilization of the heavy metals is possible without exposing the groundwater to danger by the direct use of mobile alkali metal sulphides, that is, soluble in water. In the above-mentioned example and in the relevant process variant, materials which, because of their chemical reactivity, can be used without the need for further measurement as active substances, in particular as precipitation reagents, are used together with said sulfides. The active substances within the meaning of the invention may, however, also be substances which are considered to be chemically inert. If, for example, a hard bitumen is melted, it is kneaded with clay and this mass, as soon as it is homogeneous, is mixed with calcium oxide, preferably with hydrophobic calcium oxide and again kneaded, then after some time it starts the hydration reaction that consumes water, of calcium oxide, and the originally pasty mass disintegrates to form a dispersion of solid materials in powder form, homogeneously charged with hard bitumen. The calcium hydroxide contained in this dispersion of solid materials is not, as is known, in the chemical aspect in no way inert, but possesses strongly basic properties and can therefore be easily reacted, for example with carbon dioxide, while the hard bitumen also contained in this dispersion of solid materials is totally inert from a chemical aspect. However, the mixture, present in the dispersion of solid materials, based on clay particles and calcium hydroxide, is the support material and hard bitumen of the active substance, BÍ the mission consists, for example, in making harmless by means of an irreversible immobilization highly toxic organic pollutants, such as polychlorinated biphenyls (PCB) or dioxins and dibenzofurans (PCDD / PCDF), for example as constituents in filter dusts from incineration plant of garbage or as contamination in soils. For this purpose, flying powders or soils that are contaminated in such a way are mixed with a dispersion of solid materials in the form of powders, loaded with hard bitumen, which had been prepared using clay and calcium oxide, and from the mixing occurs with consolidation? na solid phase. The hard bitumen finely dispersed in the matrix of solid materials has, after a short time, incorporated the organic pollutant materials, because of its good solubility in the solid solvent, hard bitumen. Leaching experiments under long-term conditions and using trace analytical methods demonstrate that the organic contaminating materials treated according to the invention remain immobilized in a durable and complete manner. Instead of hard bitumen, other high-boiling organic inert materials, such as hard paraffin, petroleum jelly or a mineral oil, may be present. It is impossible to carry out an enumeration of the active substances and mixtures of individual active substances, since their choice is established spontaneously according to known points of view from the respective problem posed. It is known, for example, that in the case of the production of substrates of ST plants they need trace elements in different concentration and bioavailability. Among these trace elements are copper, iron, manganese, zinc, molybdenum and boron, whose water-soluble compounds are mechanically mixed and used in the form of heterogeneous concentrates. The disadvantage of these preparations is that the said trace elements are not uniformly available for the plant, since a homogeneous distribution on the substrate is excluded. If, in contrast to this, the same compounds of said trace elements are first kneaded into a clay matrix and uniformly distributed in this manner, then, after the homogenization of this mixture with calcium oxide, a prepared from extraordinarily finely dispersed solid materials, in which the active substances are extremely homogeneous and uniform. By means of a joint dispersion of tartaric and citric acid, the bioavailability of the mentioned trace elements is previously determined. If the trace element compounds, with or without tartaric acid, are transferred individually to a dispersion of solid materials in the form of a powder and only later are they to be mixed in the quantitative ratio in each case necessary for the utilization, it is also recommended of this the joint distribution of a hydrophobicizing agent, since no disadvantageous interactions of the elements of the trace elements with one another are no longer possible within the mixture of the dispersions of solid materials in the form of individual powders. In the same way, nutritious substances of plants of the most diverse types can be transformed into extremely homogeneous long-term fertilizers, provided they are stable in the resulting alkaline medium. The number of active substances that can be used in the environmental sector is incalculably large, given that the number of pollutants that cause problems is so great. Theoretically, then for each polluting substance, but at least for each class of polluting substances, there are active substances within the meaning of the invention that can be used as participants in a reaction, for example as participants in a precipitation, condensation or addition reaction, for immobilization and decontamination, to mention just a few examples. In this context, a particularly high importance is attached to organic phases with a high boiling point as an active substance for the adsorption or absorption of both inorganic and organic contaminating materials, since this form of immobilization and physical fixation is especially simple and extensive; an example among many possible is the elimination by absorption of polluting substances from exhaust gases from waste incineration plants with the help of long chain amines as active substance. In addition to this, however, other active substances which are capable of chemical interaction with contaminating substances and therefore displace the equilibrium position in favor of total absorption, for example, can also be incorporated in the high-boiling organic phase. by long chain amines in a bituminous phase. The connection between active substances to be selected and the mission to be solved is usual for any expert in the field and therefore does not need any additional explanation; thus, it is usual for any person skilled in the art to be able to use finely dispersed metals, such as magnesium or aluminum, for the dehalogenation of chromatic compounds with a halogen content. In the second example which is set forth above, in which the use of hard bitumen as an active substance is explained, a hydrophobic calcium oxide is preferably used. It is a matter of the essence of the invention that the water contained in the suspension of finely-ground solid materials is uniformly bound in the chemical reaction with the alkaline-earth metal oxide also with mixtures of alkali-metal oxide or aluminum alcoholates or well mixtures of both classes of compounds. For the use of suspensions of solid materials in the form of powder, homogeneously loaded with active substances for agricultural or technical purposes, especially also in the field of environmental protection TS advantageous that by a suitable embodiment of the process or by subsequent mixing is adjusted an excess of calcium oxide, preferably hydrophobic calcium oxide. In this way, coherent contaminated materials can be disintegrated in a single stage of work in such a way that the active substances are evenly distributed in the medium and the contaminating materials are totally captured and made harmless. EXAMPLE 1 100 parts by weight of a natural plastic clay are homogenized in a kneader with 18 parts by weight of a calcium oxide hydrogenated with 1% of a fatty acid. The hydration reaction, which starts after about 5 minutes, is passed out of the kneader; in this case, an extraordinarily homogeneous dispersion of solid materials is formed, based on calcium hydroxide in clay, which is so homogeneous that the components are not recognizable even under a microscope.

Variation The plastic clay is kneaded first with 2% potassium sulphate as reaction retardant and then with non-hydrofuged calcium oxide. The hydration reaction begins only after approximately 20 minutes.

Variation Instead of clay, red sludge or a paste based on 70 parts by weight of spent and dry fuller's earth and 30 parts by weight of water is used.

Variant Instead of calcium oxide, the stoichiometric equivalent of a mixed alcoholate of aluminum or silicic acid esters can be used; in these cases the alcohol released during the hydrolysis is evaporated; This can be recovered by condensation.

Example 2 70 parts by weight of clay, 7.6 parts by weight of sulphate d? iron FeS04 x 7H20, 3 parts by weight d? Na2S (60%) eodium sulfide and 4 parts by weight of water are mixed in a kneader. The homogenized material is homogenized with 15.4 parts by weight of calcium oxide. There are 100 parts by weight of a dispersion of solid materials in the form of powders, homogeneously charged with 2% of iron sulfide FTS, which dispersion can be used for the precipitation of heavy metals in contaminated materials. The proportion of iron sulphate must be metered and dimensioned in such a way that an excess of 20% is present with respect to the stereometrically necessary quantity; in this way, they are prevented from reaching * - the groundwater, in the course of the treatment according to the invention, the soluble alkali metal sulfide, for example in the case of treatment of contaminated soils or contaminated production waste. The clay in this example can be completely or partially replaced by spent batter earth pastes and dried with water, for example 77 parts in spent batter earth from the feed industry with 23 parts by weight of water or with the so-called red mud, or by pasting a finely ground fine filter powder with so much water that a clay-like matrix results. The addition of retarding agents of the reaction is not necessary in this example, since iron sulphate, by analogy to alkali metal sulfates, delays the chemical reaction of calcium oxide already in such a way that total homogenization is possible before that the water-consuming reaction of calcium oxide starts. * EXAMPLE 3 In a variant with respect to Example 2, 35 parts by weight of clay with a suspension of 7.6 parts by weight of iron sulphate and 2 parts by weight of water are homogenized in a forced mixer. 35 parts by weight of clay are homogenized in a forced mixer with an aqueous solution of 3 parts in ^ * weight of sodium sulfide (60%) in 2 parts by weight of water. Both portions, after having been homogenized, are homogenized in a forced mixer and then homogenized together with 15.4 parts by weight of hydrophobic calcium oxide. It results in a dispersion of solid materials in the form of powder loaded in a 9P extremely homogeneous with 2% sulfur d? Fes iron, which can be used in the same way as in Example 1.

EXAMPLE 4 In a variant with respect to Examples 2 and 3, homogeneous materials prepared separately from clay and iron sulphate or from clay and iron sulfide are each homogenized with 7.7 parts by weight of calcium oxide or hydrophobic calcium oxide. By mixing both dispersions of solid materials in powder form, homogeneously charged with iron hydroxide or with sodium sulphide, a preparation is obtained which is especially effective in the presence of an excess of hydrophobic calcium hydroxide and at the same time can be used in a filoa biental way for the treatment of coherent materials, which contain heavy metals, since, on the one hand, the precipitation of heavy metals IOB takes place immediately with the help of the alkali metal sulfide, but on the other hand, it can not reach the medium At the same time, no trace of this sulfur is detected, since it is taken up by the sodium hydroxide present, without thereby eliminating the precipitating effect on heavy metals that have not yet been reached.

Example 5 56 parts by weight of clay are plasticized with 15 parts by weight of water and preheated to 70 ° C This suspension of finely dispersed solid materials, containing water, is homogenized in a kneader with 35 parts by weight of bitumen B 80 melted. The homogenized material is then homogenized with 56 parts by weight of calcium oxide, which had been hydrofuged with 1% of a fatty acid. A suspension of solid materials is formed in the form of powders, homogeneously loaded with bitumen, which can be used in the environmental sector for the isolation and protection of landfill bodies as well as for the immobilization of non-ionogenic, inorganic pollutants, as well as organic. For this purpose, for example in the ratio 1: 4, there is mixed with contaminated material, which contains, for example, dibenzodioxins or halogenated dibenzofurans in amounts in the range of parts per million (ppm). The exact quantitative relationships are determined by simple test experiments, determining the absorption capacity of pure bitumen against the type of contaminating substance present and the amount of this pollutant. For the absorption of substances 4Plj aluminum and aluminum isobutanolate. At this point, the clay can be replaced particularly advantageously by a red mud, since this finely dispersed system absorbs in the dry state in an especially effective manner the disxines and furans mentioned.

EXAMPLE 6 150 parts by weight of clay with a water content of 23% are plasticized in a kneader with 10 parts by weight of water and 1 part by weight of a water soluble salt of copper or manganese, or zinc, is homogenized, or molybdenum, or boron, or iron, for example in the form of the corresponding sulfates of copper, iron, manganese and zinc, or as ammonium molybdate, or as potassium etaborate. Next, the homogenized materials are homogenized in a kneader with a mixture of alkaline earth metal oxides formed by 90% calcium oxide and 10% magnesium oxide which had been hydrofuged with 0.2% of a fatty acid. The dispersions of solid materials in the form of powder, homogeneous, and loaded with the said trace elements, are mixed in a drop tube mixer in a necessary quantitative relation corresponding to the established mission. An additive is obtained for the production of substrates based on peat or composted fertilizer (compost). The hydrophobic properties of the additive produce a rapid mixing even with a peat or a very wet compost. When in the present case we talk about the mixing ratio corresponding to the established mission, that expression is understood as the diverse consumption of the plants in their different phases of growth. In case the bioavailability of some components has to be increased above the average value, the clay in the corresponding preparation is homogenized in an additional way with 1 part by weight of tartaric acid or, to increase the bioavailability again, with 1 part in weight of citric acid.

Example 7 100 parts by weight of clay or silt are plasticized with 10 parts by weight of water and homogenized with 20 parts by weight of calcium cyanamide; The homogenized material is then homogenized with 10 parts by weight of hydrophobic calcium oxide. The dispersion of materials ^ solids, thus obtained, can be used as a long-term nitrogen-containing fertilizer in agriculture.

EXAMPLE 8 In a combination of Examples 2 and 5, 100 parts by weight of clay with a suspension of 32 parts by weight of iron sulphate in 7 parts by weight of water, with 8 parts by weight of water, are successively homogenized in a forced mixer. eodium sulphide and 30 parts by weight of melted bitumen, and then homogenized with 28 parts by weight of a hydrofuged calcium oxide with 0.5% of a fatty acid. The dispersion of solid materials in the form of the resulting powder, which is homogeneously charged with the active substances sulfide of iron and bitumen can be used for the simultaneous irreversible immobilization of heavy metals and ultra-pollution-causing materials, for example PCDD / DF in filter and ash powders. correspondingly contaminated from waste incineration facilities.

EXAMPLE 9 Double excesses of the stoichiometrically necessary amounts of dipotassium hydrogen phosphate, iron sulfide and calcium carbonate are transferred by evaporation to homogeneous dispersions of solid materials by ^^^ fc ~ > analogy to the procedure explained in Example 1, using a calcium oxide that had been hydrofuged with 1% of a fatty acid. The mixing of the individual dispersions of solid materials is excellently suited to irreversibly immobilize heavy metal ions in clarification and purification sludge, compost, and in river and port sludge, by precipitation of the individual heavy metals in the form of carbonates, sulphides and phosphates Arsenic and antimony can also be chemically fixed in this way. For this purpose, the said dispersions of solid materials are incorporated simultaneously with additional lightly hydrophobic calcium oxide in the residual materials to be subjected to treatment, for example by synchronous feeding in a drop tube mixer. This makes it possible for the first time to deposit these waste materials in a neutral way for the environment without having to adopt additional security measures, or to use them as building material for land, for example for the purpose of creating land. The necessary quantitative relationships are determined by the requirements of soil mechanics; these can be determined in known suitability tests, for example by "determination of Proctor density.

Example 10 100 parts by weight of clay or a paste of aluminum hydroxide or finely dispereos zeolite or bentonite with water or a wet and spent batter earth, or 100 parts by weight of a mixture of the said suspensions of solid materials, are homogenized in a mixer with 50 parts by weight of long chain amine, for example stearylamine, and 10 parts by weight of an aminosilane, for example a trialkoxysilane, and then homogenized with 500 parts by weight of a hydrophobic calcium oxide. The dispersion of solid materials, dry, in the form of powder and homogeneous that is formed, which contains an excess of calcium oxide, can be used as such after the hydration reaction has elapsed with an amount of water that is completely not necessary estequio-metric entity, in what refers to the excess of calcium oxide, in the form of a consecutive product, that is to say a component that has calcium hydroxide as the predominant component in the quantitative sense, to realize a very large absorption or chemosorption of polluting substances in the exhaust gases of waste incineration plants, especially of dibenzodioxins and halogenated dibenzofurans.

Example 11 100 parts by weight of clay or a paste of aluminum hydroxide or zeolite or bentonite finely dispersed with water or wet spent batter earth, or 100 parts by weight of a mixture of said suspensions of solid materials, are homogenized in a kneader with 50 parts by weight of alkali metal or alkaline earth metal sulfide and then homogenized with 150 parts by weight of hydrophobic calcium oxide. The dispersion of solid solids, in the form of powder and homogeneous, which is formed, which contains an excess of calcium oxide, can incorporate, because of its hydrophobic character, easily on the surface of landfills, which consist of residues of production containing heavy metals. In this way, deposited material covering the entire surface is formed with precipitation reagents which, due to slow desorption processes (in the case of sulfur ions) or due to their difficult solubility (hydroxide) of calcium and calcium carbonate from calcium oxide), are incorporated only very slowly with rainwater as a vehicle in the landfill heap and there produce in situ reactions d? precipitation. The absolute amount of precipitation reagents needed for this andtherefore, the layer thickness of the deposited material can be easily determined from the height of the landfill heap and from the average concentration of precipitable heavy metals in this landfill heap. In an analogous manner, immobilization of polluting substances is carried out in other deposits and spillways in bulk.

Claims (25)

1. Process for the preparation of homogeneous dispersions of finely dispersed solid materials, characterized in that a suspension of finely dispersed solid materials, containing water, is mechanically homogenized with an alkaline earth metal oxide, an aluminum alcoholate, a silicic acid ether , or a mixture of these compounds, and then the homogenized material is allowed to react completely with the amount of water needed stoichiometrically.

2. Method according to claim 1, characterized in that co or suspension of finely dispersed solid materials containing water ee employ materials of natural or industrial origin. Method according to claim 1, characterized in that the suspension of finely dispersed solid materials, containing water, is obtained by the addition of water from dry, finely dispersed materials of natural or industrial origin. 4. Method according to claim 1, characterized in that fine clay, clay, as well as clay-like and clay-containing materials are used as the finely dispersed solid materials containing water of natural origin. Method according to claim 1, characterized in that production residues, such as spent fuller's earth and red mud, are used as suspension of solid materials, finely dispersed, containing water, of industrial origin. Method according to one of claims 1 to 5, characterized in that calcium oxide is used as the alkaline earth metal oxide. Method according to one of claims 1 to 6, characterized in that the alkali metal oxide¬ * Terrestrial is previously treated with reaction retarding agents. 8. Process according to claim 7, characterized in that the reaction retarding agent is a hydrophobing agent. 9. Process according to one of claims 1 to 8, characterized in that the retarding agents of the reaction are added to the suspension of solid materials. Process according to one of Claims 1 to 9, characterized in that a commercially available liquid mixed alcoholate is used as aluminum alcoholate. Method according to one of Claims 1 to 10, characterized in that mixtures of commercially available silicic acid esters are used as silicic acid esters. Method according to claim 1, characterized in that a suspension of finely dispersed solid materials containing water is homogenized mechanically with active substances in the form of powders, homogeneously charged with active substances, and the homogenized material is homogenized then with an alkaline earth metal oxide, an aluminum alcoholate, a silicic acid ester, or a mixture of these compounds. 1

3. Process according to claim 12, characterized in that the active substances are formed in situ during the preparation of the dispersion of solid materials. 1

4. Process according to claim 12 or 13, characterized in that substances are used as active substances and mixtures of useful substances in agriculture. 1

5. Process according to claim 14, characterized in that fertilizers, trace elements, crop protection agents or their mixtures are used as agriculturally useful substances. 1

6. Process according to claim 12 or 13, characterized in that active ingredients are used in an inorganic or organic reaction for the detoxification, immobilization or chemical fixing of polluting substances. 1

7. Method according to claim 16, characterized in that as participants Inorganic in a reaction, reducing metals, such as magnesium or aluminum, or precipitation reagents, such as sulfides, carbonates or phosphates, are used. 1

8. Method according to claim 12 or 13, characterized in that, as active substances, inorganic or organic adsorption and absorption agents are used for immobilization and fixation by adsorption and absorption of contaminating substances. 1

9. Process according to claim 18, characterized in that inert materials of high boiling point are used as organic adsorption or absorption agents. 20. Process according to claim 19, characterized in that hard paraffin, petroleum jelly, bitumen and bituminous materials are used as inert high-boiling materials. 21. Use of the suspension of solid materials according to one of claims 1 to 20 for agricultural or technical purposes. 22. Use of the dispersion of solid materials according to claim 21 with an excess of calcium oxide and / or an aluminum alkoxide for agricultural or technical purposes. 23. Use of the dispersion of solid materials according to one of claims 1 to 20 for the insulation, embedding and detoxification of polluting materials. 24. Use of the dispersion of solid materials according to one of claims 1 to 20 for the removal of polluting materials from exhaust gases. 25. Use of the dispersion of solid materials according to one of claims 1 to 20 for the deehalogenation of halogen-containing contaminants. In testimony of which I sign the above in this City of Mexico, D. F., on the 15th day of the month of September of 1993. BY DCR INTERNATIONAL ENVIRONMENTAL SERVICES, INC. APPOINED ING. JAVIER SAUCEDO C.