Compound comprising a mineral wool comprising a sugar

Abstract

The invention relates to a method for preparing a molded composite material, comprising preparing a mixture into which mineral wool fragments are introduced. This mixture comprises a sizing composition consisting of a sugar, a non-cementitious silica carrier separate from the wool, a non-cementitious alkali carrier separate from the wool, and water. The non-cementitious silica carrier and the non-cementitious alkali carrier, together with the water, form a mineral binder that gradually solidifies around the solid particles contained in the mixture. The mixture is then shaped into a molded composite material, particularly briquettes. The invention also relates to a method for producing mineral wool, which involves producing a molten mass that is transformed into mineral wool by means of a drawing device. The molded composite material is then introduced as a vitrifiable charge into a melting chamber, such as a cupola.

Description

Compound comprising a mineral wool comprising a sugar The invention relates to the field of adding value to mineral wool-based waste products, particularly rock wool or glass wool. Typically, waste products from mineral wool production are agglomerated into shaped compounds, often referred to as "briquettes" (other names are available, essentially depending on the geometry of the shaped compound), for recycling into the mineral wool manufacturing process. These shaped compounds, particularly in briquette form, can be fed into a melting furnace, which in turn feeds a fiberization device. This technique is particularly useful when it is desired to reintroduce particulate materials into furnaces where strong gas movement prevails. The invention thus also relates to the field of mineral wool manufacturing. According to a process known as external centrifugation, mineral wool is obtained from a molten mineral mass poured into an assembly of rotating rotors. The molten mass is expelled from the periphery of the rotors and collected by an extraction gas stream, thereby becoming fibers. The wool is then impregnated with a sizing composition. The sizing composition is sprayed onto the fibers as they form, and the mass of sized fibers is then collected in a receiving member and conveyed to a device for forming a mineral wool felt web. The size is designed to give the wool its cohesion by forming bridges between the fibers after curing and crosslinking. This process produces a significant amount of waste products. On the one hand, during fiberization, the waste products consist of solidified mineral material and sizing, typically comprising fibers and grit. On the other hand, after felt formation, waste products result from shaping cuts intended to rectify felt edges or bring the products to the correct size. Finally, it sometimes happens that the production does not meet the expected quality, and some batches are discarded. According to another process, called internal centrifugation, the molten material is fibrillated through a fibrillation member in the form of a disc perforated at its periphery. The material is expelled through the perforated disc wall as filaments, which are then extracted by a stream of extraction gas. This technique produces a much higher fibrillation yield than the external centrifugation technique and does not produce pellets. However, some cutting debris is unavoidable. These mineral-based waste products can be value-added within the mineral wool manufacturing process, particularly by remelting them with the raw materials to feed the melting furnace. This recycling typically involves preparing compounds from these waste products. Such compounds are produced by shaping, particularly by molding, a mixture of mineral wool waste products with a mineral binder, usually cement, followed by a treatment to set the binder. Forming these compounds into briquettes makes them easy to transport and facilitates their reuse, especially their reintroduction into a melting furnace. In the case of rock wool, this furnace can be, in particular, a cupola furnace, in which the solid starting material charge consists of blocks of natural rock shapes, with alternating layers of solid fuel (coke) blocks, forming a self-supporting column through which the combustion gases escape. As melting takes place at the bottom of the column, it is recharged from the top with fuel and rock. These furnaces do not allow the introduction of starting materials such as dust or light particles that lack the required capacity to form a stable layer of solid material in the vertical column. Conversion into a shaped compound, such as a briquette, confers this capacity. The goal is for the briquette to develop good mechanical strength fairly quickly after forming and not disintegrate during handling and transport. According to a recent development in the technique, it has been planned to manufacture mineral wool using sizing agents whose composition includes starting materials derived from renewable sources, particularly sugars. However, it has been observed that using a sugar-based sizing agent to bind the mineral wool results in briquettes that are not very strong, making them very difficult to manufacture and / or use. The invention solves the aforementioned problem. US2013 / 165553 discloses a briquette for use as a mineral filler in the production of synthetic glass fibers comprising a cement and recycled mineral wool waste comprising fibers in contact with a non-crosslinked binder comprising a sugar and a reaction product of a polycarboxylic acid with an amine. Document EP0768283A2 teaches the formation of briquettes manufactured by compression molding, comprising fibers and a lignin-based binder. The invention is based in part on the discovery that sugar present in the sizing agent interacts unfavorably with cement, interfering with and even preventing its solidification. While the use of cement is not excluded in the context of the present invention, it is recommended to reduce its proportion and replace it, at least partially, or even completely, with a mineral binder, which will be described below. The invention relates to a process for preparing a shaped compound, comprising preparing a mixture in which mineral wool fragments comprising a sizing agent comprising a sugar, a cement-free silica carrier other than wool, a cement-free alkali metal carrier other than wool, and water, are introduced, the cement-free silica carrier and the cement-free alkali metal carrier forming, with the water, a mineral binder that gradually solidifies around the solid particles present in the mixture, and then shaping the mixture into a shaped compound, such as a briquette. The shaping generally involves molding. The expression "mineral wool fragments" here denotes all residual products resulting from the production of mineral wool, including solidified mineral materials in the form of granules or non-fibrized or recovered materials in the form of solid fly materials or bundles of recovered fibers (by washing operations) on the different receiving or transport surfaces and also cut mineral wool felt. The expression "cement-free" indicates that the compound to which it is bonded is not a cement. A cement is an anhydrous powdered material consisting of crystalline calcium silicate or crystalline calcium aluminate. It is a hydraulic mineral compound that results in the formation, in the presence of water, of hydrated calcium silicate or hydrated calcium aluminate. A cement is essentially crystalline and comprises less than 10% by weight of amorphous material. In a cement, calcium silicate or calcium aluminate are crystalline phases. Common examples include Portland cement, white cement, high-alumina cement, sulfoaluminate cement, and natural rapid-setting cement. Slag and alkali metal silicates are not considered cements by someone skilled in the trade. The cementless silica carrier is a material with hydraulic properties, forming silicate ions in the presence of water. The cementless silica carrier may optionally be crystalline if it is readily soluble in water. This is particularly true for sodium silicate, which can be introduced into the mixture as an aqueous solution. If slag is used as the cementless silica carrier, it should preferably be amorphous (more than 80% by weight, and more preferably more than 90% by weight), contain at least 10% silica, and have a fine particle size, specifically a D50 of 100 µm or less, and more preferably less than or equal to 50 µm. Such slags can be obtained as byproducts of the iron and steel industry.These materials acquire their glassy structure, that is, their essentially amorphous nature, from the rapid cooling treatments with water applied to them after harvesting, which imparts latent hydraulic properties. When dried, the cement-free silica carrier is preferably a completely or partially amorphous solid mineral compound. It is preferably more than 80% amorphous by weight and more preferably more than 90% by weight. It preferably comprises at least 10% by weight of silica (SiO2) and more preferably at least 20% by weight of silica. Optionally, it comprises alumina. It may comprise, in reduced amounts, iron oxide, an alkali metal oxide, an alkaline earth metal oxide, a phosphate, a sulfate, a sulfide, or titanium oxide. Preferably, it is fine enough to dissolve, at least partially, in an aqueous medium.Thus, the particle size of a cement-free silica carrier is preferably such that the D50 is less than or equal to 100 pm and, more preferably, less than or equal to 50 pm. In a glass manufacturing application, the silica carrier is a source of SiO2 in the final glass. The silica carrier can, in particular, be chosen from the following list: • an alkali metal silicate; • natural or calcined clay, kaolinite, illite or montmorillonite; • calcined kaolin or dehydrated kaolin, such as mainly amorphous metakaolin which may comprise kaolinite crystals; • silica fume; • fly ash (class C, class F); • biomass ash; blast furnace slag; steelmaking slag; rice husk ash, rice husk ash; calcined synthetic or natural pozzolana; natural or calcined volcanic ash; diatomite. From the list above, it is preferable to use compounds that are not very expensive such as: slag, fly ash, calcined synthetic or natural pozzolan, calcined or natural clay, or metakaolin. Slag is a by-product of the iron and steel industry and usually shows a SiO2 / CaO ratio (by weight) < 1.5 and the sum of its CaO and SiO2 content represents more than 45% of its weight. The cementless alkali metal carrier comprises an alkali metal and forms alkali metal ions in the presence of water. It preferably comprises at least 20 wt% alkali metal (this is the percentage of the alkali metal element, such as Na or K, and not the percentage of its oxide) and, preferably, at least 30 wt% alkali metal. The cementless alkali metal carrier can be selected from the following list: • R-OH, R2CO3, RHCO3 or R2SO4 where R is chosen from Na, K or Li, • anhydrous sodium silicate or sodium silicate in the hydrated form (metasilicate Na2SiO3, disilicate Na2Si2O5, orthosilicate Na4SiO4 or pyrosilicate Na8Si2O7); or alkali metal silicate (potassium or lithium). A preferred cementless alkali metal carrier can be chosen from: NaOH, Na₂CO₃, NaHCO₃, trona (natural sodium carbonate), or an alkali metal silicate. Sodium hydroxide (NaH) is the most preferred cementless alkali metal carrier from the standpoint of its reactivity. In a glassmaking application, this alkali metal carrier is a source of alkali metal oxide (particularly Na₂O or K₂O) in the final glass. If the use of sodium hydroxide presents a problem of material corrosion, sodium carbonate, which is also particularly effective, is preferred. The mixture contains water. This water may originate largely from the moisture in the waste products collected from the fiberization plant, which uses large quantities of water, particularly for waste collection. Water may also be added to the mixture to achieve good mixing quality, moldability, and even compaction. The mixture also preferably comprises a cementless alkaline earth metal carrier. The cementless alkaline earth metal carrier comprises an alkaline earth metal and forms alkaline earth metal ions in the presence of water. It preferably comprises at least 10 wt% alkaline earth metal (this is the percentage of the alkaline earth metal element, such as Ca or Mg, and not the percentage of its oxide) and, preferably, at least 20 wt% alkaline earth metal. The cementless alkaline earth metal carrier can be selected from the following list: • Limestone or chalk (CaCO3) , • quicklime CaO or slaked lime Ca(OH)2, calcium and magnesium carbonate or dolomite (CaMg(CO3)2), • aragonite, vaterite or other polyamorphs of CaCO3. A slag can be either a cementless silica carrier or a cementless alkaline earth metal carrier, its alkaline earth metal content generally exceeding 30% by weight. Limestone, dolomite, or quicklime are preferred as cementless alkaline earth metal carriers. The particle size of the cementless alkaline earth metal carrier should be such that D50 is less than 100 pm, and preferably less than 50 pm. In glassmaking applications, this alkaline earth metal carrier (particularly CaO or MgO) is a source of alkaline earth metal oxide in the final glass. It is possible to introduce a mineral filler into the mixture, which can be selected from mineral materials that are inert with respect to the compound's binding system. These fillers can be used to improve the mechanical stability of the formed compound or as components for vitrifiable filler, enhancing its value in the glassmaking melt, particularly due to their iron content. The aggregate typically has a D50 greater than 200 pm, and in particular, greater than 1 mm. The mineral filler can be at least a filler selected from non-reactive slag or gravel.This may refer to aggregates originating from industrial recycling industries that enhance the value of industrial by-products (or co-products) or by-products (or co-products) resulting from the demolition of buildings or waste dumps (ground materials from concrete, bricks, recycled railway ballast, slag, or ground products from road surfacing or mining waste dumps). The slag used optionally herein is coarse and is not considered a cement-free silica carrier within the meaning described above, as it does not form silicate ions in the presence of water and is crystalline to more than 20% of its weight, with a large particle size and an average diameter D50 of more than 50 µm, for example, a D50 of more than 200 µm, specifically more than 1 mm. The same applies to gravel.The LD slag resulting from the converters, which solidifies without rapid water cooling after removal and thus crystallizes, can be of particular interest. This mineral charge, inert insofar as it does not participate in the briquette solidification chemistry, is nevertheless a source of starting material for the mineral fiber that will be manufactured when the briquettes are reused for melting. This aggregate charge can be introduced into the mixture that forms the mass to be molded, and thus into the finished composite, at a content of 5 to 50% by weight. The mixture is preferably produced at a basic pH, generally at least 10 and preferably at least 11. This pH is generally created by the alkali metal carrier, particularly NaOH. This high pH makes the medium aggressive towards the various carriers, which can then more readily release their ions into solution. The mixture, according to the invention, solidifies rapidly, with or without an inert mineral filler. Generally, in the context of an industrial process, such a mineral filler is present. The cementless silica carrier and the cementless alkali metal carrier are the two main ingredients of the mineral binder that will be distributed and cure around the undissolved material. The addition of an alkaline earth metal carrier to the mixture is preferred. In the case of the presence of a cementless alkaline earth metal carrier in the mixture, the alkaline earth metal ions created in the mixing water will also participate in the formation of a mineral binder. In a particularly suitable mixture according to the invention, the cement-free silica carrier comprises a sodium silicate or slag, such slag comprising at least 10% by weight of silica, being amorphous to more than 80% of its weight and having a D50 of less than 100 jm, and the cement-free alkali metal carrier comprises sodium hydroxide or sodium silicate or sodium carbonate, and a cement-free alkaline earth metal carrier comprising Ca(OH)2 or CaCO3 also present in such a mixture. The sizing composition comprising sugar generally comprises sugar in a proportion of 30 to 90% by weight of the dry matter of the sizing (% of dry sugar with respect to the total weight of dry sizing). The term "sugar" as used in the context of the present invention denotes one or more molecules selected from monosaccharides, oligosaccharides, or polysaccharides. Sugar is at least one saccharide selected from reducing, non-reducing, and hydrogenated saccharides. The term "reducing saccharide" should be understood in the conventional sense, that is, a monosaccharide or a polysaccharide bearing a free hemiacetal OH group. This group has a reducing effect, particularly in alkaline copper solutions. Examples of reducing monosaccharides include saccharides containing 3 to 8 carbon atoms, preferably aldoses, and advantageously those comprising 5 to 7 carbon atoms. The aldoses preferred are natural aldoses (belonging to the D series), particularly hexoses such as glucose, mannose, and galactose. The term "non-reducing saccharides" should be understood in the conventional sense, that is, it denotes a saccharide composed of several saccharide units, carbon 1 of which bears the hemiacetal OH group and is involved in a bond. A reducing saccharide within the meaning of the invention exhibits no reducing action in alkaline copper solutions. Examples of such non-reducing saccharides include disaccharides such as trehalose, isotrehalose, sucrose, and isosaccharides; trisaccharides such as melezitose, gentianose, raffinose, erlose, and umbelliferose; tetrasaccharides such as stachyose; and pentasaccharides such as verbascose. The term "hydrogenated saccharide" is understood to mean all products resulting from the reduction, in any form, of a saccharide selected from monosaccharides, oligosaccharides, or polysaccharides, which may be linear, branched, or cyclic, and mixtures of these products, particularly starch hydrolysates. Examples of hydrogenated saccharides include erythritol, arabitol, xylitol, sorbitol, mannitol, iditol, maltitol, isomaltitol, lactitol, cellobitol, palatinitol, maltotriol, and products of hydrogenation of starch hydrolysates. The sugar-compounded sizing agent may also include other compounds, such as a crosslinking agent, which may be selected from monomeric or polymeric polyfunctional organic acids, in particular citric acid, primary and secondary amines, aqueous ammonium or metal, or ammonium salts of organic or inorganic acids, in particular ammonium or alkali metal or metal sulfate. It may also include a reactive compound comprising ethylenic unsaturation, which may be, in particular, the product of the reaction of maleic anhydride and tetraethylpentamine, which is particularly reactive with non-reducing sugars. It may also include additives, such as a silane, for example, a silane comprising a polar terminal group, for example, aminosilane, as a coupling agent, or a silicone as a water-repellent agent.To illustrate the documents that describe the compositions for use in the invention, the documents US2010 / 0282996, US2012 / 0263934, WO2012 / 168619 and WO2012 / 168621, incorporated for reference, should be mentioned. The mineral wool fragments comprise a sizing agent containing sugar even before being introduced into the mixture and coming into contact with the other mixture ingredients (in addition to, if appropriate, a small amount of water already present in the mineral wool fragments). The introduction of the mineral wool, sizing agent, and sugar into the mixture is thus simultaneous; these three ingredients combine within the mineral wool fragments before being introduced into the mixture. Mineral wool fragments typically consist of rock wool or glass wool. These fragments are usually incorporated into the mix at a ratio of 10 to 60% by weight. Mineral wool fragments comprising the sugar-containing sizing may be a waste product from rock wool manufacturing. The main components of rock wool are: SiO2: 32 to 47% by weight AbO3: 15 to 22% by weight CaO+MgO: 20 to 40% by weight Iron oxide: 5 to 15% by weight Mineral wool fragments comprising the sugar-containing sizing may be a byproduct of conventional glass wool manufacturing. The main components of rock wool are: SiO2: 50 to 75% by weight AbO3: 0 to 8% by weight CaO+MgO: 5 to 20% by weight Iron oxide: 0 to 3% by weight Na2O+K2O: 12 to 20% by weight B2O3: 2 to 10% by weight Mineral wool fragments comprising the sugar-containing sizing may be a byproduct of the manufacture of alumina-rich glass wool. The main components of this alumina-rich glass wool are: SiO2: 35 to 50% by weight AbO3: 10 to 30% by weight CaO+MgO: 12 to 35% by weight Iron oxide: 2 to 10% by weight Na2O+K2O: 0 to 20% by weight The mineral wool fragments comprising the sugar that makes up the sizing are generally introduced into the mixture at a proportion of 10 to 60% by weight (percentage of dry wool fragments; it is understood that the fragments are generally introduced into the mixture in a wet state). The mineral wool may optionally be lightly ground before being introduced into the mixture to facilitate blending, but it retains its fibrous nature since fibers longer than 5 mm are clearly distinguishable to the naked eye. The sizing composition included in the mineral wool fragments is generally present in a proportion of 0.1 to 10% by weight and more particularly in a proportion of 0.5 to 7% by weight of dry sizing matter with respect to the total weight of dry wool fragments. The sum of the weights of cementless silica carriers and cementless alkali metal carriers can represent 5 to 30% by weight of the mixture. Of course, if a compound has the property of being both a cementless silica carrier and a cementless alkali metal carrier, it is counted only once in determining this sum by weight. Preferably, the sum of the number of moles of silica introduced into the mixture by the cementless silica carrier and the number of moles of alkali metal introduced into the mixture by the cementless alkali metal carrier is greater than 0.5 moles per kg of mixture. This sum is generally between 0.5 and 3 moles per kg of mixture. Preferably, the ratio of the number of moles of silica introduced into the mixture by the cementless silica carrier to the number of moles of alkali metal introduced into the mixture by the cementless alkali metal carrier ranges from 0.2 to 3. Preferably, the cement-free silica carrier introduces into the mixture at least 0.1 moles of silica per kg of mixture, in particular up to 3 moles of silica per kg of mixture, preferably 0.1 to 2 moles of silica per kg of mixture. Preferably, the cement-free alkali metal carrier introduces into the mixture at least 0.1 moles of alkali metal per kg of mixture and, preferably, from 0.1 to 1.5 moles of alkali metal per kg of mixture. The presence of an alkaline earth metal carrier is preferred. If present, the alkaline earth metal carrier preferably introduces at least 0.3 moles of alkaline earth metal per kg of mixture into the mixture, in particular up to 3 moles of alkaline earth metal per kg of mixture, and preferably from 0.3 to 2 moles of alkaline earth metal per kg of mixture. Cement must not be introduced into the mixture, and if cement is introduced into the mixture, it is introduced in a proportion of less than 8% and, preferably, less than 4% and, more preferably, less than 3% by weight of the mixture. Preferably, the ratio of the weight of cement to the weight of the cement-free silica carrier, which preferably comprises at least 10% by weight of silica, is less than 1 and, preferably, less than 0.5. According to a particularly suitable mixture, the cementless silica carrier and the cementless alkaline earth metal carrier comprise one and the same slag (meaning that both are at least partially present within the same slag), and the cementless alkali metal carrier comprises sodium carbonate. The cement is introduced into the mixture in a proportion of less than 8%, and preferably less than 4%, and more preferably less than 3% by weight of the mixture. Water is present in the mixture, preferably in a proportion of 5 to 30% by weight of the mixture. Preferably, according to this particularly suitable mixture, more than 50% of the moles of silica introduced into the mixture by the cementless silica carrier and more than 50% of the moles of alkaline earth metal introduced into the mixture by the cementless alkaline earth metal carrier are introduced by the same slag.Preferably, according to this particularly suitable mixture, more than 50% of the number of moles of alkali metal introduced into the mixture by the cement-free alkali metal carrier is introduced into the mixture by sodium carbonate. If cement is introduced into the mixture, it is preferably introduced in a proportion of at least 0.1% by weight of the mixture. The mixture for preparing the mass to be molded can be produced in any suitable mixer. Heating the mixture by introducing heat from the outside is generally unnecessary. The temperature of the mixture may increase due to the dissolution of certain ingredients, such as sodium hydroxide. Water is added in sufficient quantity to distribute the mineral binder throughout the mass to be molded, but insufficient to prevent the molded compound from retaining its shape upon removal from the mold, if applicable, after compaction. Typically, water is present in the mixture at a proportion of 5 to 30% of the mixture's weight. The mass obtained from the mixing process is subsequently shaped into a compound, specifically briquettes, by molding and, optionally, compaction. In particular, the mass to be molded can be placed in a mold, vibrated to remove trapped air, and then, optionally, compacted by applying pressure to one of the mold's movable surfaces. The briquettes can, for example, have a volume of more than 20 cm³, specifically between 100 and 1000 cm³. The resulting compound cures naturally. It may dry out over time, significantly reducing its water content during storage. Its water content may vary depending on storage conditions. Another aspect of the invention is a shaped compound obtained by the processes according to the invention. Finally, one theme of the invention is a process for manufacturing mineral wool in which a molten mass is produced that is converted into mineral wool by means of a fiberization device, a shaped compound obtained according to the invention that is introduced as a vitrifiable charge into a melting chamber, such as a cupola furnace. In the following examples, a series of examples (A) of base binder formulations are first presented, demonstrating the effectiveness of the mixture according to the invention in the presence of fibers for preparing shaped compositions in an experimental context. In another series of mixtures (B), the formulations incorporate aggregates of mineral fillers. Examples A1 to A17 The ingredients shown in Table 1 are mixed in a mixer. The quantities indicated are parts by weight in grams of dry matter, in addition, of course, to the "Total Water" column, which sums all the water added to the mixture, regardless of its form. Table 1 shows the mineral waste products originating from dust recovery at different stages of the mineral wool manufacturing process, which can be considered vitrifiable particulate or pseudofiber materials. These are considered inert mineral fillers that do not participate in binder formation. Table 1 (parts by weight) The mineral wool fragments comprise a rock wool fiber and a sizing composition comprising a sugar. The content of these mineral wool fragments is broken down in Table 1 between the mineral component (column "fiber") and the sizing composition. The sizing comprises, under dry conditions, 68 wt% sucrose, 12 wt% ammonium sulfate, 0.5 wt% silane, and 19.5 wt% maleic anhydride and tetraethylpentamine additives. The latter two compounds are mixed together before being blended with the other ingredients of the sizing composition. The mineral wool fragments were introduced into the mixture in the wet state. In Table 1, the "Fiber" column gives the quantities of fragments without water or sizing composition. The "Sugar-Containing Sizing" and "Phenolic Resin" columns give the quantities of sizing materials that were deposited on the rock wool. The "Total Water" column gives the sum of the water initially introduced by the fragments and the added water. The cement used was Portland cement. The active slag was blast furnace slag and comprises (% by weight): SiO2 32.3% CaO 38.2% (i.e., 27.3% Ca) MgO 9.2% (i.e., 5.54% Mg) Al2Oa 14.9% and also other oxides in a smaller proportion that complete its composition to 100%. The slag was more than 90% amory by weight. This slag is both a cement-free silica carrier and an alkaline earth metal carrier. Its particle size was fine since its D90 was less than 90 pm and its D50 was 30 pm. The sizing composition comprises, in its dry state, 68 wt% sucrose, 12 wt% ammonium sulfate, 0.5 wt% silane, and 19.5 wt% maleic anhydride and tetraethylpentamine additives. The latter two compounds are mixed together before being blended with the other sizing composition ingredients. Sodium silicate is both a silica carrier and an alkali metal carrier. It comprises 28.3 wt% SiO2 and 21.7 wt% Na. It was more than 80 wt% amorphous. Test specimens measuring 4 cm x 4 cm x 16 cm were produced by vibration molding and then removed from the mold. Two types of tests were conducted. Some involved preparing 4 x 4 x 16 cm³ test specimens on which compressive strength tests were performed, measured in MPa. For these tests, the compositions in Table 1 were used without the addition of inert vitrifiable material from the inert slag or gravel type to the mixture, as this is not necessary for testing the mineral binder according to the invention. The results of these tests are reported in the left-hand side of Table 2 in the column "Compressive Strength (MPa) in 4 x 4 x 16 cm" as a function of the number of days (from 3 to 28 days). For other tests, the same compositions as in Table 1 were prepared, except that the fiber was omitted.The sizing material was added to the composition without being pre-deposited on the fiber. In this test, the setting time of the mixture was evaluated during curing, giving it a rating from 0 (no soundness) to 3 (very good soundness), based on the resistance to spatula penetration as a function of the number of days (from 1 to 28 days). These results are reported on the right side of Table 2 in the column "Setting time (0 to 3) with respect to the paste (without fibers)". Table 2 It was found that samples with high cement content, when combined with a sugar-based sizing agent, led to poor results. Samples A5 and A10, which contain the highest amount of alkaline earth metal carrier, yielded the best results in terms of compressive strength. In particular, a comparison of samples A4 and A10 shows that increasing the amount of alkaline earth metal carrier significantly improves the results. This is because, as shown in Table 1, the compositions of these two samples are identical except for the addition of a small amount of CaCO3 in sample A10. Table 3 gives the mole numbers of cement-free silica, cement-free alkaline earth metal, and cement-free alkali metal for the mixtures in the examples in Table 1. Table 3 The compositions shown in Table 1 lack high inert mineral filler contents to facilitate the preparation of test samples for curing tests. However, in actual use, inert mineral filler aggregates, such as gravel or coarse inert slag, are typically introduced into the mixture. These two fillers are crystalline and composed of large particles and do not contain silica, alkali metal, or alkaline earth metal within the scope of the invention. Examples B1 to B17 illustrate compositions with higher inert mineral filler contents. Examples B1 to B17 Table 4 gives the weight percentages of all mixture ingredients corresponding to those in Table 1, to which, however, 24 parts by weight of inert mineral filler aggregates have been added, consisting of 14 parts by weight of gravel and 20 parts by weight of inert coarse slag. The "inert mineral filler" column represents the sum of the percentages of all inert fillers introduced, including the mineral waste products shown in Table 1. Table 4 (% by weight) Table 5 gives the number of moles per kg of briquette of different carriers and some ratios for the compositions of the examples in Table 4. Table 5

Claims

i. A process for preparing a shaped compound characterized in that it comprises: -the preparation of a mixture in which mineral wool fragments comprising a sizing agent comprising a sugar, a cementless silica carrier other than wool, a cementless alkali metal carrier other than wool, and water, are introduced into the cementless silica carrier and the cementless alkali metal carrier, forming, with the water, a mineral binder that gradually solidifies around the solid particles present in the mixture, and then -shaping the mixture into a shaped compound, the term "cementless" indicating that the compound to which it is bonded is not a cement, wherein a cement is: -an anhydrous powdered substance composed of crystalline calcium silicate or crystalline calcium aluminate, -a hydraulic mineral compound leading to the formation of hydrated calcium silicate or hydrated calcium aluminate in the presence of water,and essentially crystallized and containing less than 10% by weight of amorphous material.

2. The process according to the preceding claim, characterized in that the pH of the mixture is at least equal to 10 and preferably at least equal to 11.

3. The process according to any of the preceding claims, characterized in that the mineral wool fragments comprise rock wool or glass wool.

4. The process according to any of the preceding claims, characterized in that the mineral wool fragments are introduced into the mixture in a proportion of 10 to 60% by weight of the mixture.

5. The process according to any of the preceding claims, characterized in that the sum of the weights of the cement-free silica carriers and cement-free alkali metal carriers represents 5 to 30% by weight of the mixture.

6. The process according to any of the preceding claims, characterized in that the mixture comprises 5 to 50% by weight of aggregates,in particular with a D50 of more than 200 pm.

7. The process according to any of the preceding claims, characterized in that the sum of the number of moles of silica introduced into the mixture by the cementless silica carrier and the number of moles of alkali metal introduced into the mixture by the cementless alkali metal carrier is greater than 0.5 moles per kg of mixture, in particular between 0.5 and 3 moles per kg of mixture.

8. The process according to any of the preceding claims, characterized in that the sizing composition is present in the mineral wool fragments in a proportion of 0.1 to 10% by weight and more particularly in a proportion of 0.5 to 7% by weight of dry sizing material with respect to the total weight of dry wool fragments.

9. The process according to any of the preceding claims,characterized in that no cement is introduced into the mixture, or in that the cement is introduced into the mixture in a proportion of less than 8%, and preferably less than 4%, and more preferably less than 3% by weight of the mixture.

10. The process according to any of the preceding claims, characterized in that no cement is introduced into the mixture, or in that cement is introduced into the mixture, the ratio of the weight of the cement to the weight of the cementless silica carrier is less than 1, and more preferably less than 0.

5.

11. The process according to any of the preceding claims, characterized in that the ratio of the number of moles of silica introduced into the mixture by a cementless silica carrier to the number of moles of alkali metal introduced into the mixture by an alkaline earth metal carrier ranges from 0.2 to 3.

12. The process according to any of the preceding claims, characterized in that the cementless silica carrier introduces at least 0.

13. The process according to any of the preceding claims, characterized in that the cement-free alkali metal carrier introduces into the mixture at least 0.1 moles of alkali metal per kg of mixture and preferably from 0.1 to 1.5 moles of silica per kg of mixture.

14. The process according to any of the preceding claims, characterized in that a cement-free alkaline earth metal carrier other than wool is present in the mixture, in particular in a proportion of at least 0.3 moles of alkaline earth metal per kg of mixture, in particular up to 3 moles of alkaline earth metal per kg of mixture and preferably from 0.3 to 2 moles of alkaline earth metal per kg of mixture.

15. The process according to any of the preceding claims,characterized in that the cement-free alkaline earth metal carrier comprises Ca(OH)₂ or CaCO₃.

16. The process according to any of the preceding claims, characterized in that the cement-free silica carrier comprises a sodium silicate or a slag, the slag comprising at least 10% by weight of silica, which is amorphous to more than 80% of its weight and has a D₅₀ of less than or equal to 100 pm.

17. The process according to any of the preceding claims, characterized in that the cement-free alkali metal carrier comprises sodium hydroxide or sodium silicate or sodium carbonate.

18. The process according to any of the preceding claims, characterized in that water is present in the mixture in a proportion of 5 to 30% of the weight of the mixture.

19. The process according to any of the preceding claims,characterized in that sugar is present in the sizing composition in a proportion of 30 to 90% by weight of the sizing dry matter.

20. The process according to any of the preceding claims, characterized in that the D50 of the cement-free silica carrier is less than or equal to 100 pm and preferably less than or equal to 50 pm.

21. The process according to any of the preceding claims, characterized in that the cement-free silica carrier and the cement-free alkaline earth metal carrier comprise one and the same slag and the cement-free alkali metal carrier comprises sodium carbonate, the cement is introduced into the mixture in a proportion of less than 8% and, preferably, less than 4% and, more preferably, less than 3% by weight of the mixture, and water is introduced into the mixture preferably in a proportion of 5 to 30% by weight of the mixture.

22. The process according to the preceding claim,characterized in that the cement is introduced into the mixture in a proportion of at least 0.1% by weight of the mixture.

23. The process according to either of the two preceding claims, characterized in that more than 50% of the number of moles of silica introduced into the mixture by the cementless silica carrier and more than 50% of the number of moles of alkaline earth metal introduced into the mixture by the cementless alkaline earth metal carrier are introduced by the slag itself.

24. The process according to any one of the three preceding claims, characterized in that more than 50% of the number of moles of alkali metal introduced into the mixture by the cementless alkali metal carrier is introduced into the mixture by sodium carbonate.

25. The process according to any one of the preceding claims, characterized in that the formed compounds are briquettes,The conversion of the mixture into briquettes is achieved by molding and optional compaction.

26. A process for the manufacture of mineral wool in which a molten mass is produced that is converted into mineral wool by means of a fiberization device, characterized in that a shaped compound obtained according to any of the preceding claims is introduced as a vitrifiable charge into a melting chamber, such as a cupola furnace.