WO2006015647A1 - Method for producing a mineral melt and shaped brick - Google Patents

Abstract

The invention relates to a method for producing a mineral melt for producing mineral fiber products, particularly rock wool for producing insulating materials for thermal insulation, soundproofing and fireproofing, substrates for cultivating plants, reinforcing fibers, and fibers for filtration purposes, during which a charging material is heated in a melting unit until the melting temperature is reached. Residual substances at least from the production of mineral fiber products and/or correcting substances for adjusting the necessary composition and viscosity of the melt are added to the charging material, and the residual substances and/or correcting substances are comminuted and compacted with a binding agent to form shaped bricks, and the shaped bricks are introduced into the melting unit. In order to improve a method of the aforementioned type for producing a mineral melt for the production of mineral fiber products or of a shaped brick whereby reducing the costs for the raw materials but not degrading the properties of the mineral fiber products to be produced and, in particular, with regard to their insulating properties and biosolubility, the invention provides that dried sludge, which at least partially substitutes for the correcting substances, is added to the shaped bricks.

Description

 Process for producing a mineral melt and shaped stone

The invention relates to a method for producing a mineral melt for the production of mineral fiber products, in particular rock wool for the production of insulation materials for thermal, acoustic and fire protection, Sub¬ straten for plant breeding, of reinforcing fibers and fibers for Filtrati¬ onszwecke in which a feed material is heated in a melting unit until reaching the melting temperature, wherein the feedstock residues are added at least from the production of mineral fiber products and / or correction materials for adjusting the required composition and viscosity of the melt and wherein the residues and / or correction substances are comminuted and pressed with a binder into shaped bricks and the shaped bricks are fed into the melting aggregate. Furthermore, the invention relates to a shaped block for use in a mineral melt for the production of mineral fiber products, in particular rock wool for the production of insulation materials for thermal, acoustic and fire protection, substrates for plant breeding, Ver¬ strengthening fibers and fibers for filtration purposes, consisting of comminuted and bound with at least one binder residues from the production of mineral fiber products and / or from the dismantling of mineral fiber products and / or correction materials for setting the required composition and viscosity of the melt.

Rock wool insulation materials are used for heat, sound and / or fire protection. Further, rock wool products are used to grow plants or to strengthen, e.g. Coating materials and other products or as fibers used for filtration purposes. In the following, the exemplary listed rock wool products are summarized as mineral fiber products be¬ draws.

The prior art discloses processes for the production of mineral melts for the production of mineral fiber products. These mineral fiber products consist of glassy solidified inorganic mineral fibers which are produced by means of a melting process. In this melting process Suitable raw materials are melted and then the resulting melt melted in a defibration unit. The fraying of the melt takes place, for example, in a so-called drawing, spinning or blowing process. Immediately after defibering, the mineral fibers are either wetted dropwise with binders and / or impregnating agents or obtained a coating of binders and / or impregnating agents, so that they are subsequently pointwise interconnected. The fiber mass treated in this way can subsequently be collected, deformed and the resulting structure fixed by curing the binders. Reinforcing fibers and fibers for filtration purposes are generally not treated with binder and / or impregnating agent.

After the composition of the fibers, a distinction is made between commercially available glass wool and stone wool. Rock wool is mainly made from blends of crushed effusion rocks, such as basalt or diabase and small amounts of limestone, dolomite and magnesite as supplements and lumps of coarse slag. These supplements may each be added to the mixture alone or in different mixtures with each other.

Increasingly, the mixture of natural, broken to the erforderli¬ size size raw materials are replaced by artificially produced body entspre¬ ing size, shape and strength, which are composed of various raw materials and residues and suitable binders. These bodies are referred to below as shaped bricks.

The stones may contain fine-grained broken natural rocks. Other components include production-related residues, beispiels¬ from the coarse constituents inevitably resulting in the manufacturing process, such as molten beads, the solidified melt with regular emptying of the melting furnaces together with the partially melted rock residues and parts of the furnace lining of refractory materials, and the insulating materials or substrates used in the trimming of an endless incurred fibrous web. Other production-related residues are Ver¬ leftovers, defective products or aufzuschmelzende used insulation or substrates.

The production-related residues are processed for the production of molded bricks, i. crushed, ground and then mixed with correction materials.

The granular and fibrous components, the internal residues and the correction substances are predominantly mixed with inorganic binders, usually with the addition of water, and then pressed into moldings.

Inorganic binders are generally hydraulic setting Zemen¬ te as Portland cements CEM I ₁ but also all kinds of special cements, such as high-alumina cements to understand. The proportions of the binder in the Form¬ stones are about 9 to 15% by mass.

After reaching a sufficient stability of the stones for storage in the heap, the promotion and Beschi¬ ckung - in general, the stones after 3 days, for example, a minimum compressive strength of 3 to 5 MPa reach - these are together with the other raw materials or alone, but always together with the required lumpy fuels, the smelting aggregate abandoned

With a corresponding particle size (0 to 8 mm) and particle size distribution and in particular with correction substances having relatively low ash contents, it is possible to dispense with incorporation into the shaped block if the correction substances can be introduced into the melting unit via direct injection. For this purpose, the correction substances are blown directly into the oven cavity of the shaft furnace, where they melt in contact with the hot furnace gases. The quantity of conveyed material can be adjusted via a dosing unit. The conveyed material is stored in a closed silo, then passes into a Vor¬ storage container under which the metering unit, z. B. a rotary valve, ensures the ent speaking mass flow. The medium used is mostly air. At the end of the delivery line there is a lance, which is installed in the center of the primary wind jet of the shaft furnace. Each primary wind nozzle can be equipped with a lance. The mode of operation of the injection system depends on the material to be conveyed (melting behavior) and depends in particular on the absorption capacity of the primary wind nozzle.

With the help of the correction substances, which are brought in via the shaped blocks and / or pneumatically ein¬, the required composition of the mixture is achieved, the kerk bewirk¬ a uniform and rapid melting in the melting. At the same time, the temperature and the viscosity of the resulting melt are influenced to such an extent that the most effective, uniformly occurring defibering process is achieved.

Correction substances are, for example, slags from the steel industry, such as convergent or ladle slag or melt chamber granules from coal power plants.

Correction substances also include substances which contain iron in oxidic and / or metallic form. Suitable ores are hematite (Fe ₂ Oa) or magnetite (Fe ₃ O ₄ ), as well as slags from the iron and steel industry

In the melting unit, the melt required for fiber formation is produced, which is then fed to the fiberizing aggregate. As a rule, the fiberizing unit consists of several rolls rotating at high rotational speed and offset one above the other.

The processability of the mineral melt has a strong dependence on the viscosity and the temperature of the melt. Both parameters can be selectively influenced by the choice of raw materials. In addition, affects the chemical composition of the melt and thus the mineral fiber products produced therefrom on their biosolubility, ie the eventual residence time of the mineral fibers in the human organism. This biosolubility results to a significant extent from the proportions of the oxides and compounds of silicon, aluminum, titanium, sodium, magnesium, potassium, calcium, iron and their relationships to one another. Furthermore, the contents of the oxides and compounds of boron and phosphorus are also important for biosolubility.

A typical composition of a mineral melt for the production of commercial, bio-soluble rock wool is composed essentially as follows:

From US-A-4 617 045 a method for producing a homogeneous melt for the production of mineral wool insulating materials is known. These insulating materials are produced from waste products, namely, on the one hand from the production of residual materials and on the other hand cement kiln dust, slags and ash from the sediment. These starting materials are homogenized in a mixture and mixed with a binder. Subsequently, briquettes are herefrom briquetted, the wer¬ a melter supplied to the. In this case, the resulting melt is supplied with hot burnout gases in order to homogenize the melt chemically and heat it up to a predetermined temperature. The thus prepared melt is then defibered in the usual way. The ash removed from the sediment is a residue during the combustion of pulverulent coal, so that the ash residues are present in powder form.

Furthermore, WO 97/22563 describes a process for the production of mineral fibers. In this prior art method is provided that molded bricks are formed of mineral material and then melted. Here, the blocks form only part of a batch to be melted. The stones have a specific material containing aluminum-containing sand contaminated with foundry residues. In addition, the shaped bricks may contain other industrial wastes such as, for example, converter slag or other slags from steelmaking, glass, mineral fiber cement, power plant ash, wood ash, steel mill dust and artificially produced fiber products, although the aluminum-containing sand and the other industrial grades Waste represents at least 50% of the total components.

A process for the production of mineral fibers is also known from WO 00/76929, wherein the mineral fibers should have at least 14 wt .-% AI2O3. From this document it is known to arrange in a furnace a charge to be melted of a mineral material containing shaped bricks which, after melting, is withdrawn from the furnace and defibered. In this vor¬ known method, it is provided that the shaped blocks have a specific, alumi¬ nium-containing material having an average size of less than 700 microns at a content of at least 50% by weight of A ^ Os and a porosity of at least 20 %, wherein the porosity is provided by pores having a diameter of less than 1 μm. The blocks may also contain waste materials from the production process and binders.

Furthermore, WO 99/28248 discloses a process for the production of mineral fibers in which it is provided that the mineral fibers have at least one constituent of 14% by weight Al ₂ O ₃ , a batch of a starting material comprising arranged in an oven, the batch is melted in the furnace to a melt and the melt is fiberized into mineral fibers. Here, the batch should contain ferrochrome slag.

WO 99/28252 discloses a process for the production of mineral fibers in a proportion of at least 14 wt .-% Al ₂ O ₃ , wherein in a shaft furnace, a self-supporting column of a mineral charge is placed, containing the stones, the batch to provide a Melt is melted in the base region of the furnace, which melt has the composition required for the mineral fibers to be produced. Furthermore, it is provided that the melt is withdrawn from the base region of the furnace and defibered. At least one quarter of the aluminum contained in the charge is provided as a special mineral-containing mineral in the shaped bricks, this mineral containing aluminum containing between 0.5 and 10% by weight of metallic aluminum, 50 to 90% by weight. % Al ₂ O ₃ and 0 to 49.5% by weight of other materials.

Finally, WO 2004/041734 A1 discloses processes for producing a mineral melt for the production of mineral fibers in which residual materials and correction substances originating from at least production are comminuted to adjust the required composition and viscosity of the melt, the residual substances and the correction substances with a Binders are bound and pressed into shaped bricks, wherein the shaped bricks are fed to a melting aggregate zu¬. In this prior art method components of the blocks are at least partially substituted by combustion residues, wherein the combustion residues are granular.

Accordingly, it is provided in the case of this previously known method that the correction substances mixed with the residues originating from the production for the production of the molded blocks are at least partially substituted by combustion residues. The substitution achieves a substantial reduction of the binder, in particular of the cement fraction, which is normally required, which results in a substantial improvement in the economic viability of the manufacturer. ment of such molding blocks results. For this purpose, it is also provided that the combustion residues are granular in order to ensure a good cohesion of the stones.

Based on this prior art, the invention has the object to further develop a generic method for producing a mineral melt for the production of mineral fiber products or a molded block such that on the one hand reduces the cost of raw materials, but at the same time Properties of the mineral fiber products to be produced are not deteriorated and improved in particular with regard to their insulating properties and biosolubility.

The solution of this problem provides, in the case of a method according to the invention, that the molded bricks are supplied with dried sewage sludge which at least partially substitutes, in particular, the correction substances.

As a solution to the task, a shaped block is also proposed, which comprises dried sewage sludge as constituent, the dried sewage sludge in particular at least partially substituting the correction substances

The composition of the sewage sludge varies depending on the origin of the sewage or on the method of sewage sludge treatment.

In the sewage treatment plant, the wastewater passes through different clarification stages such as compaction plant, sand trap, primary clarification, activation and secondary clarification. In the mechanical cleaning, the non-dissolved solids are removed from the wastewater in the first place. In the biological stage of the sewage treatment plant, the dissolved impurities (carbon, phosphorus and nitrogen) are removed from the wastewater with the aid of special bacteria. The resulting sewage sludge is further treated in the digester (anaerobic digestion). By subsequent dehydration and drying a dry residue of up to 90% can be achieved. Preferably, a dried sewage sludge with a dry residue> 85% is used. Sewage sludges with lower dry contents are also suitable, but make higher demands on the conveyor. For example, sewage sludge with dry residues <85% are conveyed, in particular with screw conveyors. The use of a pneumatic conveying system is not readily possible with these sewage sludge.

An advantage of the dried sewage sludge is to be seen in a usually vorgenom¬ menen and required thermal treatment that kills pathogenic (pathogenic) pathogens. The dried sewage sludge is thus hygienised, which considerably simplifies the handling of the sewage sludge. On the other side, in dried sewage sludge, explosion and fire protection measures must be taken into account.

The chemical composition of a usable sewage sludge is shown exem¬ plarisch in the following table:

The use of sewage sludge makes it possible to substitute in a substantial proportion individual constituents presently contained in bricks for the production of mineral fiber products. As a result, the proportion of dried sewage sludge in the shaped bricks can be up to 20% by mass. If the sludge is introduced directly into the melt, in particular blown in, the injection quantity can be up to 5% of the raw material input from dried sewage sludge.

The dry sewage sludge described above has a chemical composition which is particularly suitable for the correction of the mineral melt for the production of mineral fibers. The dried sewage sludge can be used, for example, for targeted viscosity control of the mineral Use melt. This viscosity has a decisive influence on the product properties of the mineral wool.

Furthermore, the proportion of aluminum oxide (Al 2 O 3) in the sewage sludge and / or the shaped bricks enables the substitution of other alumina supports. The aluminum oxide itself promotes the biosolubility of the mineral fibers.

In addition to the above-mentioned effects on an inventive method for producing a mineral melt for the production of mineral fiber products, the inventive method also has the advantage that the dried sewage sludge can be recycled material. In this way, the costs in sewage treatment plants are reduced, so that the sewage sludge can generally be taken off the sewage treatment plants free of charge.

The method according to the invention therefore opens up a further sensible and environmentally friendly use of sewage sludge in addition to landfilling, thermal utilization / disposal, agricultural use, composting and use in landscaping.

In addition, in experiments with the method according to the invention, the surprising advantage has been found that the carbon content contained in the sewage sludge is converted into latent heat, so that a reduction of the gas or oil consumption can be achieved in the thermal afterburning. In particular, when blowing in addition, an increase in the H ₂ content is achieved, so that the CO concentration increases in the exhaust gas.

In addition to the actual intended use of dried sewage sludge in the production of mineral fiber products, this form of utilization also significantly relieves the environment.

Furthermore, it is essential that such dried sewage sludge can usually be purchased cheaply, so that the production costs of mineral fibers serprodukte be significantly reduced and these products can be supplied to a larger appli- cation area. The increase in insulation performance in thermal insulation leads to a drastic reduction of the primary energy requirement in the heating and cooling of buildings.

Further features and advantages of the invention emerge from the subclaims and the example of an advantageous embodiment of a method according to the invention or a shaped block according to the invention which is shown below.

According to one embodiment of the invention, molded bricks consisting of 38 to 64 mass% of production-related residues, 5 to 20 mass% dried sewage sludge, 0 to 11 mass% converter slag, 0 to 14 mass% ladle slag, 10 to 25 Mass% Al ₂ θ ₃ carrier, and 9 to 15 mass% cement. In this composition, in comparison with a corresponding composition of shaped bricks according to the prior art, in particular the proportion of ladle slag (Fe ₂ O ₃ and CaO support) is substituted, resulting in a reduction of the production costs of the molded bricks.

As production-related residues, solidified melts, separated spherical or columnar glass particles and / or defective or recycled mineral fiber insulation products, filter dusts from the production process, residues of remainders and / or parts of a refractory furnace lining are used. The constituents are comminuted to a particle size of <7 mm and pressed with a Portland cement microfine grain size as a binder into shaped bricks with a polygonal cross-section. The proportion of Portland cement is 10% by mass. The shaped bricks, together with a primary energy source, for example coke and effusion rocks, for example basalt and diabase, are given off and melted to form a melting aggregate designed as a cupola. A resulting melt is deposited above a slag bed of the cupola furnace. pulled and fed to a fiberizing aggregate. The fiberizing unit has a plurality of spinning wheels, which are driven in rotation at high peripheral speed. The enamel is broken down into microfine mineral fibers by means of these spinning wheels. The mineral fibers are then wetted with at least one binder and deposited on an endless conveyor, for example a conveyor belt. Subsequently, mineral fiber insulating products in the form of plates, shaped bodies or webs are produced from a fiber web formed therefrom. The Mineralfaserdämmstoffprodukte can have different fiber profiles.

Claims

claims 1. A process for producing a mineral melt for the production of mineral fiber products, in particular rock wool for the production of insulation materials for thermal, acoustic and fire protection, substra¬ th for plant breeding, of reinforcing fibers and of fibers for Filt¬ rationszwecke, in a feed material is heated in a melting unit until the melting temperature is reached, the residues being added to the feed material at least from the production of mineral fiber products and / or correction substances for adjusting the required composition and viscosity of the melt, and the residual substances and / or The correction substances are comminuted and pressed into shaped bricks with a binder, and the shaped bricks are introduced into the smelting unit, which means that the shaped bricks are supplied with dried sewage sludge, which in particular at least partially substitutes the correction substances. 2. The method of claim 1, dad urch geken nzeichn et that as solidified solidified melts, deposited spherical or stem glass particles and / or defective, or recycled products of the production of insulation materials from mineral fibers, filter dusts from the manufacturing process, mixtures residues and / or parts a refractory furnace lining crushed and pressed into shaped bricks. 3. Method according to claim 1 or 2, characterized in that the residues are mixed with the correction substances and with the binder. 4. The method according to claim 1, characterized in that the shaped bricks together with effusion rocks, for example salt and / or diabase and / or blast furnace slag are fed to the smelting unit. 5. The method according to claim 1, dad urch in that the dried sewage sludge as inorganic silicate and / or aluminated and / or ferritic existing, in particular finely formed particles is added to a molding blocks to Roh¬ mass. 6. The method according to claim 1, characterized in that the dried sewage sludge is formed as granules and introduced as such in the melting unit, in particular blown. 7. The method of claim 1, dad urch in that the blocks are bonded with at least one inorganic binder, ins¬ particular a cement, wherein the shaped blocks are preferably bound with 9 to 15 mass% of binder. 8. The method according to claim 1, characterized in that the dried sewage sludge completely substitutes the correction substances. 9. Method according to claim 1, characterized in that the shaped bricks are formed with a proportion of <20% by mass of dried sewage sludge. 10. The method according to claim 6, characterized dken u rch nzeichn et that <5% by mass of the feed material is blown in as a dried sewage sludge. 11. The method according to claim 1, characterized in that the carbonaceous constituents of the dried sewage sludge are gassed. 12. The method according to claim 1, d ad u rchken draws that the correction materials from granular ores, such as hematite or magnetite and / or residues from the power plant and / or Metallhütten¬ economy and preferably in an amount of 20 to 50 Mas - se-% are contained in the form stones. 13. Method according to claim 1, characterized in that the correction substances have a grain size of from 0 to 20 mm, in particular from 1 to 7 mm. 14. Method according to claim 1, characterized in that the correction substances comprise alkaline earths and phosphates for reducing the viscosity and / or Al ₂ O ₃ for increasing the biosolubility. 15. shaped brick for use in a mineral melt for the production of mineral fiber products, in particular rock wool for the production of insulating materials for thermal, acoustic and fire protection, of substrates for plant breeding, of reinforcing fibers and of fibers for filtration purposes, consisting of comminuted and bound with at least one binding agent residues from the production of mineral fiber products and / or from the dismantling of mineral fiber products and / or correction materials for adjusting the required composition and viscosity of the melt, characterized by dried sewage sludge as a component, in particular, at least partially substitutes the correction substances. 16. A shaped brick according to claim 15, characterized in that the residues solidified melts, separated spherical or stem glass particles and / or defective, or recycled products of the production of insulating materials from mineral fibers, filter dusts from the manufacturing process, mixtures residues and / or parts of a refractory O. - have fenauskleidung. 17. A shaped brick according to claim 15, characterized in that the dried sewage sludge has inorganic silicate and / or aluminimatic and / or ferritic, in particular finely formed particles. 18. A shaped brick according to claim 15, characterized in that the dried sewage sludge is formed as in a melter inflatable granules. 19. A molded block according to claim 15, dad urch geken nzeichn et that is formed as an inorganic binder as a cement, wherein the binder content is preferably 9 to 15 mass%. 20. A shaped brick according to claim 15, characterized in that the proportion of dried sewage sludge is <20% by weight. 21. A shaped brick according to claim 15, characterized Porsche Style nzeichnet that granular ore, for example, hematite or magnetite and / or Reststof¬ fe from the power plant and / or Metallhüttenwirtschaft is preferably provided in a proportion of 20 to 50 mass% as correction materials , 22. The molded brick according to claim 15, characterized in that the correction substances have a grain size of from 0 to 20 mm, in particular from 1 to 7 mm. 23. The molded block according to claim 15, characterized in that the correction substances comprise alkaline earths and phosphates for reducing the viscosity and / or Al ₂ O ₃ for increasing the biosolubility.