NL192261C - Inorganic material suitable for cleaning gases and liquids and method for manufacturing such a material. - Google Patents

Description

1 192261

Inorganic porous material suitable for cleaning gases and liquids and method for manufacturing such material

The present invention relates to an inorganic porous material based on cement and / or lime and SiO2-rich supplement, which contains uniformly dispersed, finely divided additive for the absorption and / or reaction with harmful substances from contacted with the material gases and / or liquids. The invention also relates to a method of manufacturing such a material.

Such a material is known from German patent application DE 3,400,764. According to that application, the material is made from a conventional cement and added active substance, of which 10 pellets are formed. To impart some porosity to the solid pellets, activated carbon is added in an amount of 10-30% by weight.

The drawback of such a material is that although the activated carbon imparts porosity to the material, the cement phase itself, through which the additive is distributed, is a massive mass. The added substance will therefore largely be contained in the cement.

15 Only the added substance that is in direct or indirect contact (via the activated carbon) with the environment can exert its specific effect. In addition, much of the porosity is not for reaction ..................

available, because the additive is distributed only by the cement and not in the activated carbon.

The present invention now provides a better material as mentioned in the preamble, characterized in that it also contains at least one porosifying agent and has undergone hydrothermal treatment in an autoclave whereby the material has a high porosity with thin intermediate walls, wherein the material has a specific surface area of> 10 m2 / g at a grain size fraction of 10-30 mm, and where the additive is firmly anchored on the surface of the partition walls.

In addition, it is noted that an inorganic porous material is known from European patent application 117,300. This material is used there as an adsorbent for the removal of contaminants from the process water of papermaking and related industries. However, it is nowhere suggested to use additives that can incorporate harmful substances or react with harmful substances. The specific surface area of that material is 33 m2 / g at a particle size of substantially <20 µm.

The material according to the invention is suitable for cleaning gases and liquids loaded with harmful substances. This can be done in particular in a bulk layer filter.

The material according to the invention works well because the additive comprises a substance with a high adsorption capacity for organic, non-polar components of an exhaust gas or waste water, selected from carbon, graphite and / or activated carbon, or because the additive contains a substance with a high adsorption capacity for acidic components of an exhaust gas or waste water, selected from a calcium and / or magnesium carbonate and / or hydroxide, or because the additive comprises a substance with a reducing action, selected from a pure metal, such as iron or zinc, and / or a metal alloy in powder form, or in that the additive comprises a substance with an oxidizing agent selected from a peroxide and / or with a catalytic action selected from an oxide or hydroxide of iron, chlorine, 40 vanadium, titanium, manganese, copper, zinc and / or tin.

The invention also relates to a method as mentioned in the preamble for the production of Vein, an inorganic material with a high open porosity based on cement and / or lime and SiO2-rich supplement and at least one porous agent (matrix components), wherein the matrix components mixed with water and at least one additive to absorb and / or react with noxious substances from gases and / or liquids contacted with the material, foamed and then autoclaved with steam curing and after removal be broken from the autoclave and / or classified if desired to the desired grain size.

The method is preferably characterized in that a water / solid ratio of 0.3-0.7 is set in the suspension.

According to a further preference, the method is characterized in that the steam curing is carried out at 0.6-1.6 MPa (6-16 bar) and with an autoclave residence time of 2-5 hours.

Due to the special structure of the foam concrete-like support matrix, the additives are largely arranged over the surface, but firmly connected to the support matrix, so that although a stable '' filter '' is available on the one hand, an optimum of 55 reaction surface is also available on the other. is made available.

According to the invention, the matrix components (cement, lime, SiO2-rich additive, porosifying agent) are mixed with water and one of the aforementioned additives until a strongly pore-containing 192261 2 suspension has set up. This is then, optionally after filling in a corresponding form, subjected to curing with steam in an autoclave. In this hydrothemic curing, lime and silicic acid - the addition of cement is effected in order to obtain sufficient stability of the primarily formed foam mass - react with each other to form the calcium silicate phases forming the solid matrix.

Surprisingly, not all of the additives participate in the hydrothermal cure.

Tests have shown that the additives, even after the hydrothermal reaction, are homogeneously distributed and in very fine particles in some sense bound to the calcium silicate hydrate phase by "incorporation", occur in all surface areas.

Mixtures of 20-70 parts by weight of matrix material and 80-30 wt. parts of added substance are preferred.

Within the framework of the matrix material, finely ground quartz sand, natural sand and / or an ash, preferably a filter or fly ash, can be used as the supplement. Aluminum powder and / or surfactants are preferably used as the porosifying agent.

In order to optimize the distribution and the reactivity of the additive or substances, these must be mixed as homogeneously as possible and in finely divided form during the preparation.

The water / solid ratio depends on the starting materials used and is preferably 0.3-0.7, more preferably 0.4-0.6.

The steam curing should preferably be carried out at 0.6-1.6 MPa (6-16 bar), more preferably at 0.8-1.2 MPa (8-12 bar), with autoclave residence times of 2- Turned out to be optimal for 5 hours.

Autoclave treatment can be further optimized if the autoclave is vented prior to admission of pressurized water vapor. The venting can take place, for example, by purging with water vapor (preferably at atmospheric pressure), but also by temporarily placing the autoclave under vacuum, for example with a vacuum pump. In the former variant, the water vapor expresses the air between the individual particles of the applied material. In the second variant, the air is sucked out between the solid particles.

In a third version of the lining, the procedure is that of first bringing the autoclave with water vapor under a pressure of X kPa. The air between the particles is compressed and does not escape at first. By subsequently relieving (pressure drop), the air between the particles is extracted and simultaneously extracted. The greater the pressure drop (maximum to atmospheric pressure), the more energetic the venting takes place. Tests have shown that a relaxation of 1.105-2.105 Pa is sufficient to effect almost complete venting. After venting, the pressure is raised to the desired final pressure.

Tests have further shown that, as a rule, it is sufficient to raise the vacuum to about 70% in order to discharge so much air that a sufficient space of pores is then available for the water vapor subsequently supplied under pressure to be completely and uniformly into the cavity and thereby allow the hydrothermal reaction to take place.

The inorganic material produced in this way can be used either in the shape in which it is, for example, extracted from a shape, or, for example, also in block form, as a filter.

According to a particularly preferred embodiment, the material is then reduced or classified by cutting, breaking, sieving or blowing in order to be able to finish it to a grain size adapted to the application.

In the application, the material of the invention proves to be particularly advantageous because the additives applied to the surface for the inclusion or reaction with the harmful substances of the gas or the liquid are particularly fixed there because of the hydrothermal pretreated 45 so that the bulk material is available as a reaction medium for a long time.

The material is simple and inexpensive to manufacture and can therefore be used in hitherto inaccessible areas of application for gas and waste water treatment.

Various implementation examples are given below for further explanation.

In all examples, autoclaving is performed at 1.2 MPa (12 bar) with saturated water vapor for 4 hours. The starting materials all belong to a grain size fraction of less than 100 µm.

Claims (4)

1. Inorganic porous material based on cement and / or lime and SiO2-rich supplement, which contains uniformly dispersed, finely divided additive to absorb and / or react with harmful substances from gases and / or liquids brought into contact with the material, characterized in that it also contains at least one porosifying agent and has undergone hydrothermal treatment in an autoclave whereby the material has a high porosity with thin intermediate walls, the material having a specific surface area of> 10 m2n / g at a grain size fraction of 10-30 mm, and wherein the additive is firmly anchored to the surface of the partition walls. 2. A method for manufacturing an inorganic material with a high open porosity based on 192261 4 cement and / or lime and SiO 2-rich additive and at least one porous agent (matrix components), wherein the matrix components are added with water and at least one additive to absorb and / or react with harmful substances from gases and / or liquids that have been brought into contact with the material, mixed, foamed and then subjected to steam curing in an autoclave and, if necessary, after removal from the autoclave to desired grain size can be broken and / or classified. Process according to claim 3, characterized in that a water / solid ratio of 0.3-0.7 is set in the suspension. 3 192261 Example I Carrier matrix: finely ground quartz: 16% fine whitewash :. 8% cement (PZ 45): 6% 5 aluminum powder: 0.1% Additive: limestone flour: 69.9% To the combined dry mixture, add water to set a water / solid ratio of 0.4. The slurry so formed rose to the primary foam mass, which was subjected to autoclaving and then broken to a grain size of 10-20 mm. The material thus obtained shows a high absorption capacity with respect to acidic exhaust gas components (e.g. SO2HF, HCl, etc.) and the specific surface area (BET) of this granule fraction was about 10 m2n / g. Example II Compared to Example I, white lime hydrate was used as the additive and the water / solid ratio was corrected to 0.5 (due to the greater water requirement of the white lime hydrate more finely divided compared to limestone flour). The other parameters remained unchanged. At a high absorption capacity again with respect to acidic exhaust gas constituents, the specific surface area (BET) at a grain fraction of 10-20 mm was approximately 13 m2n / g. Example III Carrier matrix: finely ground quartz: 24% fine whitewash: 12% cement (PZ 45): 9% aluminum powder: 0.2% Additive: activated carbon: 54.8% With otherwise equal parameters, a water / solids ratio of 0.5 was set and then the material was broken to a grain size of 15-30 mm. The material showed a high adsorption capacity for organic components of exhaust gases and waste water. The term "inclusion of and / or reactions with harmful substances" also includes other reaction partners. Example IV Carrier matrix: finely ground quartz: 20% fine whitewash: 10% cement: 7.5% 40 aluminum powder: 0.2% Additive: iron powder: 62.3% With water / solids slightly reduced compared to example III dust ratio (0.45), after the hydrothermal cure, an inorganic material was obtained which exhibited excellent reducing properties relative to oxidizing components of gases and liquids. 4. Process according to claim 2 or 3, characterized in that the steam curing is carried out at 6-16 bar and with an autoclave residence time of 2-5 hours.