METHOD FOR PRODUCING MINERAL WOOL FROM UNTREATED MINERAL MATERIALS

Description

[0001] The invention relates to the field of melting a mixture of raw materials, in particular for the manufacture of mineral wool as used in particular in the field of thermal and / or acoustic insulation of buildings or other applications. It is more particularly concerned with mineral wools of the rock wool type, that is to say whose chemical compositions result in a high liquidus temperature and high fluidity at their fiberizing temperature, associated with a high glass transition temperature.

[0002] Conventionally, this type of mineral wool is fiberized by so-called "external" centrifugation processes, for example of the type using a cascade of centrifugation wheels fed with molten material by a static distribution device, as described in particular in patents EP-0 465 310 or EP-0 439 385. For certain rock compositions, fiberization can alternatively be done by centrifugation through perforated plates. The molten material passes into a spinneret then into continuous fiberizing plates from which it emerges in the form of glass threads which are sprayed with polymer (the binder) to form a mat. After adding binders and other elements specific to each use, the wool mat is polymerized and calendered.

[0003] In addition to the criteria of quality and industrial and economic feasibility, which have been added in recent years to that of the biodegradable nature of mineral wool, namely its capacity to dissolve rapidly in a physiological environment, with a view to preventing any potential pathogenic risk linked to the possible accumulation of the finest fibres in the body by inhalation, a composition of rock-type mineral wool adapted accordingly has been proposed in WO 00 / 17117 or EP1667939B1, to which reference will be made for further details on this technique.

[0004] The molten mixture is usually prepared by melting in a furnace raw materials comprising silica and possibly a secondary source of silicon such as recycled mineral fibers, at least one source of alkaline earth in the form of limestone (calcium carbonate) and / or dolomite (CaMg(CO 3 ) 2 ) and a source of aluminum such as bauxite.

[0005] Documents CN 112 299 701 A, US 6 346 494 B1, WO 02 / 051766 A1, EP 0 525 816 A1 and Zagar, L. et al., Sprechsaal (114), 01.07.1981, p. 496-512 reveal, for example, the use of natural minerals as raw materials for the manufacture of mineral wool. During melting, the carbonates release carbon dioxide, the bubbles of which contribute to the stirring of the mass during melting. Furthermore, certain carbonates such as dolomite, even before releasing their CO 2 , break down into finer particles according to the phenomenon known as decrepitation, which can be quite violent and generate dust which clogs and even corrodes the various conduits equipping the furnaces (chimneys, regenerators, etc.). In a conventional rock wool manufacturing process, CO2 emissions due to the melting of raw materials are generally around 20 to 25% of the total mass of raw materials used.Furthermore, carbon dioxide is a greenhouse gas and it is desirable to develop mineral wool manufacturing processes that generate as little CO2 as possible for environmental reasons, while still producing a good quality product at an acceptable cost.

[0006] In addition to the release of CO2 directly during the melting process of the raw material bath, it is therefore important to consider the rock wool manufacturing process as a whole, taking into account other factors such as the energy cost of making said raw materials available for use in the rock wool manufacturing process, in particular if transformations or syntheses are necessary for their use as a raw material.

[0007] In summary, in order to reduce energy costs and optimize the CO2 balance, it is important to take into account all the stages leading to the formation of mineral wool fibers and not just the last stage of melting the raw material bath described above.

[0008] The object of the present invention is to contribute to solving such a technical problem by proposing a process for manufacturing rock wool for which CO2 emissions are effectively reduced, on the basis of all the steps leading to the formation of rock wool and for which the material transformation steps before melting the bath have been optimized.

[0009] This mixture of raw materials is intended to be heated to a temperature and under conditions allowing its melting to obtain a molten bath meeting the said final target composition of the mineral wool.

[0010] The originality of the present invention lies in the choice of raw materials. Indeed, it has been discovered that it is possible to use natural mineral oxides, i.e. in their initial geological composition after their extraction from their deposit, in particular without chemical alteration aimed at modifying the initial composition, i.e. mineral materials not chemically transformed as a source of magnesium and / or calcium, this choice leading to the reduction of the release of CO 2 during the fusion reaction. In particular, according to the method of the present invention, the initial basis is the exact composition of these untransformed geological mineral materials, as precisely determined by any suitable technique (for example chemical analysis, X-ray diffraction, etc.) to determine the composition of the initial bath.More specifically, on the basis of this initial determination of the composition of the mineral matter, the necessary proportions of the other components of the initial bath (such as silica, bauxite, limestone or dolomite) are calculated and adjusted to arrive at said target composition; in this way, the quantity of CO2 released is minimized, as measured over all the stages leading to the formation of the mineral fibers and the preparation of the raw materials, and not only on the basis of the final stage of melting the rock mixture.

[0011] According to the invention, however, said mineral oxides can of course undergo steps prior to their use as raw material for fusion but without chemical transformation of the crystalline grains constituting the mineral oxide. Such steps can be crushing, screening, washing or even flotation, magnetic separation or any other physical separation of the impurities present between said grains of the mineral matter.

[0012] The choice of the raw materials mentioned above is essential to obtain good quality mineral wool, particularly after its fiberization. Among the properties considered essential, we can cite in particular the melting yield (ratio between the quantity of wool produced and the quantity of raw materials fed into the furnace), and for the embodiments in which the manufacturing process includes fiberization by a centrifuge, the quality of the refining which results in a minimal number of residual bubbles in the molten bath, the homogeneity of the material (in particular the homogeneity in SiO 2 ), as well as the number of unmelted particles.

[0013] More specifically, the present invention relates to a method for manufacturing mineral wool having a target composition, comprising the melting of a mixture of raw materials constituting a melt bath, said target composition meeting the following criteria, in weight percentages: SiO 2 : between 30 and 50%, Na 2 O: between 0 and 20%, CaO: between 6 and 35%, MgO: between 1 and 15%, CaO and MgO: between 11 and 40% cumulatively, Al 2 O 3 : between 10 and 27%, K 2 O: between 0 and 15%, Iron oxide: between 0.5 and 15%, other oxide(s): between 0 and 5% cumulatively, preferably less than 3%, the remainder being made up of unavoidable impurities, said process being characterized in that it comprises the following steps: a) the raw materials of said melt are selected, including at least: a source of silicon chosen in particular from silica, basalt, recycled mineral fibers or their mixtures, preferably silica, preferably at least one basalt, optionally at least one source of sodium preferably chosen from sodium hydroxide NaOH, sodium carbonate Na 2 CO 3 or a mixture of sodium hydroxide NaOH and calcium carbonate Na 2 CO 3 , at least one source of calcium chosen from a natural mineral calcium silicate comprising,in weight percentage, more than 30% of SiO 2 and more than 10% of CaO, CaO and SiO 2 together representing more than 70% of the weight of said silicate, and / or at least one source of magnesium chosen from a natural mineral magnesium silicate comprising, in weight percentage, more than 30% of SiO 2 and more than 10% of MgO, MgO and SiO 2 together representing more than 70% of the weight of said silicate, said sources of calcium and / or magnesium being natural mineral materials, i.e. derived from a natural geological environment and not transformed, optionally limestone CaCO 3 optionally a complementary source of aluminum such as bauxite, optionally a complementary source of magnesium such as a magnesium oxide, optionally a complementary source of iron such as an iron oxide, b) the composition of said natural sources of calcium and / or magnesium and / or aluminum is determined, c) on the basis of the or said compositions determined according to point b),the necessary quantities of said raw materials are determined to obtain a mixture of said target composition, d) the mixing of said materials is carried out according to said quantities, e) the melting, fiberizing and cooling of said mixture are carried out under the conditions allowing said mineral wool to be obtained.

[0014] According to particular and advantageous embodiments of the present invention which can of course be combined with each other where appropriate: A source of calcium is a natural mineral calcium silicate comprising, in weight percentage, more than 30% SiO 2 and more than 15% CaO, CaO and SiO 2 together representing more than 70% of the weight of said silicate, preferably more than 75% or even more than 80% of the weight of said silicate. A source of magnesium is a natural mineral magnesium silicate comprising, in weight percentage, more than 30% SiO 2 and more than 15% MgO, MgO and SiO 2 together representing more than 70% of the weight of said silicate, preferably more than 75% or even more than 80% of the weight of said silicate. A source of calcium as previously described and a source of magnesium as previously described are used.Said source of magnesium is a natural mineral material corresponding to the following composition, in percentages by weight: SiO 2 : between 40 and 55%, preferably between 45 and 50%, Al 2 O 3 : between 0 and 10%, for example between 1 and 10% MgO : between 20 and 40%, preferably between 25 and 35%, MgO and SiO 2 representing in total preferably at least 70%, or even at least 75%, Fe 2 O 3 : between 0 and 4%, for example between 1 and 3% less than 5% of other oxides, preferably less than 3% of other oxides possibly water, in particular present in said source in the form of hydroxide(s), preferably in an amount of less than 20% and in particular between 5 and 15%.Said source of magnesium is a natural mineral material corresponding to the following composition, in percentages by weight: SiO 2 : between 55 and 70%, preferably between 58 and 65%, Al 2 O 3 : between 0 and 10%, for example between 1 and 10% MgO : between 20 and 40%, preferably between 25 and 35%, MgO and SiO 2 representing in total preferably at least 85%, or even at least 90%, Fe 2 O 3 : between 0 and 4%, for example between 0.5 and 2%, less than 5% of other oxides, preferably less than 3% of other oxides, possibly water, in particular present in said source in the form of hydroxide(s), preferably in an amount of less than 20% and in particular between 5 and 15%.Said source of magnesium is a natural mineral material corresponding to the following composition, in percentages by weight: SiO 2 : between 30 and 50%, preferably between 35 and 45%, Al 2 O 3 : between 0 and 10%, for example between 1 and 5% MgO : between 25 and 45%, preferably between 30 and 40%, MgO and SiO 2 representing in total preferably at least 70%, or even at least 75%, Fe 2 O 3 : between 0 and 10%, for example between 5 and 10% less than 5% of other oxides, preferably less than 3% of other oxides possibly water, in particular present in said source in the form of hydroxide(s), preferably in an amount of less than 20% and in particular between 5 and 15%.Said source of calcium is a natural mineral material corresponding to the following composition, in percentages by weight: SiO 2 : between 30 and 55%, preferably between 35 and 50%, CaO: between 35 and 55%, preferably between 40 and 50%, CaO and SiO 2 representing in total preferably at least 80%, or even at least 85%, Fe 2 O 3 : between 0 and 4%, for example between 0.1 and 0.5% Al 2 O 3 : between 0 and 5%, for example between 0.5 and 2% CO 2 : between 0 and 20%, in particular between 5 and 15% less than 5% of other oxides, preferably less than 3% of other oxides.Said source of calcium is a natural mineral material corresponding to the following composition, in percentages by weight: SiO 2 : between 40 and 55%, preferably between 40 and 50%, CaO: between 10 and 20%, CaO and SiO 2 representing in total preferably at least 55%, or even at least 60%, Al 2 O 3 : between 10 and 40%, for example between 25 and 35% Fe 2 O 3 : between 0 and 4%, for example between 0.1 and 1% less than 5% of other oxides, preferably less than 3% of other oxides. At least one source of magnesium as described above and at least one source of calcium as described above are used as raw materials. The two sources of calcium as described above are used as raw materials. Said source of calcium is a natural mineral material chosen from basalt rocks.Said source of magnesium and / or calcium is a natural mineral material corresponding to the following composition, in percentages by weight: SiO 2 : between 40 and 60%, preferably between 42 and 55%, CaO: between 5 and 25%, preferably between 10 and 20% MgO: between 3 and 20%, preferably between 5 and 15%, Al 2 O 3 : between 0 and 20%, for example between 5 and 15% Fe 2 O 3 : between 0 and 20%, for example between 5 and 15% less than 5% of other oxides, preferably less than 3% of other oxides between 0 and 5% of water, in particular present in said source in the form of hydroxide(s). At least one source of magnesium as described above is used as raw material and a natural mineral material chosen from basaltic rocks as described above is used as source of magnesium and / or calcium.At least one source of calcium as described above is used as raw material, preferably both sources of calcium as described above, and as source of magnesium and / or calcium a natural mineral material chosen from basaltic rocks as described above. All the silicates present in the bath represent more than 20% of the total weight of said bath excluding silica and cullet if they are present, preferably more than 30%, or even more than 40% or even more than 45% of the total weight of said bath excluding silica and cullet, or even more than 50% of the total weight of said bath excluding silica and cullet. Recycled mineral fibers are introduced into the melt, the recycled mineral fibers preferably representing between 1 and 50% of the total weight of the melt, preferably between 3 and 40% of the total weight of the melt.said target composition meets the following criteria, in weight percentages: SiO 2 : between 30 and 50%, preferably between 35 and 45%, Na 2 O: between 0 and 10%, preferably between 0.4 and 7%, CaO: between 10 and 35%, preferably between 12 and 25%, MgO: between 1 and 15%, preferably between 5 and 13%, CaO+MgO: between 11 and 40% cumulatively, Al 2 O 3 : between 10 and 27%, K 2 O: between 0 and 2%, preferably between 0 and 1%, Iron oxide: between 0.5 and 15%, preferably between 3 and 12%, other oxide(s): between 0 and 5% cumulatively, preferably less than 3%, the remainder being made up of impurities inevitable.Said previous target composition meets the following criteria, in weight percentages: SiO 2 : between 30 and 50% Al 2 O 3 ; between 10 and 20% CaO + MgO : between 20 and 40% cumulative Na 2 O + K 2 O : between 1 and 10% Said target composition meets the following criteria, in weight percentages: SiO 2 between 39 and 50% Al 2 O 3 between 16 and 27% CaO between 6 and 20% MgO between 1 and 5% Na 2 O between 0 and 20% K 2 O between 0 and 15% P 2 O 5 between 0 and 3% Fe 2 O 3 between 1.5 and 15% B 2 O 3 between 0 and 2% TiO 2 between 0 and 2%. Said previous target composition meets the following criteria, in weight percentages: less than 9%, cumulatively of Na 2 O and K 2 O (Na2O+K2O > 9%) and / or less than 20% cumulatively of MgO and CaO (MgO+CaO < 20%). The invention also relates to the mixture of raw materials as described previously.

[0015] Hydroxides (OH) possibly present in natural mineral matter are considered according to the present invention as oxides and as part of the chemical composition of the source, unlike free water (i.e. present in the form of humidity in the natural mineral matter).

[0016] It was thus possible to obtain defect-free rock wool mineral fibres from the initial mixture according to the invention as will be shown in the following examples.

[0017] According to the invention, as little carbonate as possible, or even no carbonate, is introduced into the mixture of raw materials. Preferably, the sum of the weight of alkali carbonate and alkaline earth carbonate is less than 50%, and preferably less than 30%, and preferably less than 10%, and preferably less than 5% by weight, or even zero in the mixture of raw materials. According to a possible advantageous embodiment, the mixture of raw materials is free of any carbonate. It is advantageously capable of releasing substantially no carbon oxide when heated and melted into mineral wool.

[0018] One of the silicon-bearing raw materials can be introduced into the raw material mix in the form of sand as a primary or secondary source of silicon. Also, a primary or secondary source of silicon can be glass cullet.

[0019] A possible aluminium-bearing raw material can be introduced into the raw material mixture in the form of bauxite Al 2 O 3 or feldspar powder such as phonolite or Nepheline (syenite), as a primary or secondary source of aluminium.

[0020] An optional iron-bearing raw material may be introduced into the raw material mix in the form of iron oxide bauxite as a primary or secondary source of iron.

[0021] The mixture of raw materials is heated until a molten bath is obtained, generally in a furnace. The heating is carried out at a higher or lower temperature and for a longer or shorter time depending on the quality of mineral fibers required, in particular depending on the degree of tolerance for unmelted particles (called "unmelted"). Generally, the heating temperature of the initial mixture is between 1200 and 1700°C for complete melting. For the transformation of the mixture of raw materials, melting techniques well known to those skilled in the art can be used. This transformation can be carried out in any type of furnace such as an electric electrode furnace, an overhead burner furnace such as a cross-burner furnace or a loop furnace, or a submerged burner furnace.

[0022] For heating and melting, the mixture of raw materials may be introduced into a furnace in a powdered state, which implies that each raw material it contains is in a powdered state or in the form of briquettes, the introduction being able to be done in one or more stages. For heating and melting, the mixture of raw materials may be introduced into a furnace in a compositional state comprising cullet and the mixture of raw materials, the latter being powdered where appropriate.

[0023] The following examples, given purely for illustrative purposes, show the advantages obtained by applying the present invention. Examples

[0024] Selon une première serie d'exemples,different mixtures of raw materials are prepared in order to compare a mixture as currently used for the manufacture of rock wool for an identical composition, which has approximately the following formulation in weight percentage of oxides: [Table 1] Elements Pourcentage poids% SiO 2 39 CaO 32,5 MgO 6,5 At 2 or 3 18,6 Fe 2 O 3 0,9 Na 2 O 0,5 K 2 O 0,3 TiO 2 0,6 others (cumulated) <2% Example 1 (art antérieur)

[0025] In a first example, a typical mineral composition of rock wool is synthesized, corresponding to the previous formulation, using current techniques.

[0026] Table 2 below gives the proportions of the different raw materials (in weight percentage) and the final composition of the mixture thus obtained, excluding impurities: [Table 2] Bath SiO 2 At 2 or 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO 2 H 2 O Name formulas grams % weights Sable SiO 2 349,80 99,60 0,05 0,01 0,03 0,03 0,49 bauxite At 2 or 3 237,50 14,20 77,51 0,26 0,23 0,61 0,43 2,53 3,42 Oxide-fer Fe 2 O 3 1,90 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Na-carbonate Na 2 CO 3 8,50 58,32 0,10 41,49 Limestone CaCO 3 428,00 0,54 0,08 0,19 0,01 55,33 0,27 0,05 44,11 Dolomites CaMg(CO 3 ) 2 293,50 1,88 0,48 0,28 0,09 29,52 21,40 0,28 0,02 47,80 Final roche composition (% poids) 39,0 18,6 0,7 0,1 32,5 6,5 0,9 1,0

[0027] The mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1430°C until the mixture is completely melted for a total duration of 2 hours 15 minutes including 90 minutes of refining. The quantity of CO2 released is 332 grams. Example 2 :

[0028] In this example the mix of raw materials is this time as described in table 3 below.

[0029] In this initial mixture, a natural mineral material of magnesium and silicon oxide "Luzenac" was introduced as a reagent to replace the dolomite, directly from a quarry located in Luzenac in France. Analysis of this material by classical chemical techniques and X-ray diffraction shows that this mineral material is essentially made up of a mixture of chlorite Mg 4.882 Fe 0.22 Al 1.88 1Si 2.96 O 10 (OH) 8 (55% by weight), talc Mg 3 S 14 O 10 (OH) 2 (42% by weight) and less than 5% by weight of dolomite.

[0030] Hydroxides are considered according to the present invention as part of the chemical composition of the source, unlike free water (i.e. present in the form of humidity in the natural mineral matter). They are reported in the table below in H 2 O equivalent.

[0031] This mineral material is directly introduced, without any chemical transformation and after simple grinding aimed at adapting its granulometry, with the other constituents in proportions adjusted accordingly to obtain a molten bath of oxides with a composition very close to that of reference example 1, and to minimize the release of CO2. [Table 3] bath SiO 2 At 2 or 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO 2 H 2 O Name formulas grams % weights Sable SiO 2 261,00 99,60 0,05 0,01 0,03 0,03 0,49 bauxite At 2 or 3 219,20 14,20 77,51 0,26 0,23 0,61 0,43 2,53 3,42 Oxide-fer Fe 2 O 3 0,20 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Na-carbonate Na 2 CO 3 10,00 58,32 0,10 41,49 Limestone CaCO 3 582,40 0,54 0,08 0,19 0,01 55,33 0,27 0,05 44,11 « Luzenac » 196,5 48,80 7,90 0,67 31,8 1,49 0,3 8,54 Final composition (% weight) 39,0 18,6 0,75 0,1 32,5 6,5 0,9 0,9

[0032] As in Example 1, the mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1430°C until the mixture is completely melted for a total duration of 2 hours 15 minutes including 90 minutes of refining. The quantity of CO 2 released this time is 261 grams, a reduction of 22% compared to the reference example. Example 3:

[0033] In this example the mix of raw materials is this time as described in table 4 below.

[0034] In this initial mixture, another natural mineral material of magnesium and silicon oxide, directly from a quarry "Trimouns" also located in Luzenac in France, was introduced as a reagent to replace the dolomite. Analysis of this material using conventional techniques shows that this raw mineral material is essentially made up of another mixture of chlorite Mg 4.882 Fe 0.22 Al 1.88 1Si 2.960 O 10 (OH) 8 and talc Mg 3 Si 4 O 10 (OH) 2 .

[0035] This material is directly introduced, without any chemical transformation and after simple grinding to adapt its granulometry, mixed with the other constituents in proportions adjusted accordingly to obtain a molten bath of oxides with a composition very close to that of reference example 1. [Table 4] Bath SiO 2 At 2 or 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO 2 H 2 O Name formulas grams % weights Sable SiO 2 231,71 99,60 0,05 0,01 0,03 0,03 0,49 bauxite At 2 or 3 238,70 14,20 77,51 0,26 0,23 0,61 0,43 2,53 3,42 Oxide-fer Fe 2 O 3 1,30 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Na-carbonate Na 2 CO 3 9,70 58,32 0,10 41,49 Limestone CaCO 3 584,50 0,54 0,08 0,19 0,01 55,33 0,27 0,05 44,11 « Trimouns » 198 61,67 0,19 0,02 31,52 0,68 4,84 Final composition (% weight) 39,0 18,6 0,7 0,1 32,5 6,5 0,9 0,9

[0036] As in Example 1, the mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1430°C until the mixture is completely melted for a total duration of 2 hours 15 minutes including 90 minutes of refining. The quantity of CO 2 released this time is 262 grams, a reduction of 21% compared to the reference example. Example 4 :

[0037] In this example the mix of raw materials is this time as described in table 5 below.

[0038] In this initial mixture, another natural mineral, a magnesium silicate, directly from a quarry in Carino, Spain, was introduced as a reagent to replace the dolomite. The oxide composition of this mineral is given below. [Table 5] Bath SiO 2 At 2 or 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO 2 H 2 O Name formulas grams % weights Sable SiO 2 288,0 99,6 0,05 0,01 0,03 0,03 0,5 bauxite At 2 or 3 233,8 14,2 77,5 0,3 0,23 0,61 0,43 2,53 3,42 Oxide-fer Fe 2 O 3 1,30 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Na-carbonate Na 2 CO 3 9,40 58,32 0,10 41,49 Limestone CaCO 3 580,00 0,54 0,08 0,19 0,01 55,33 0,27 0,05 44,11 " Cute " 170,8 39,1 2,4 0,04 0,05 1,50 36,5 8,2 12,15 Final composition (% weight) 39,0 18,6 0,7 0,1 32,5 6,5 2,2 0,1

[0039] As in Example 1, the mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1430°C until the mixture is completely melted for a total duration of 2 hours 15 minutes including 90 minutes of refining. The quantity of CO 2 released this time is 260 grams, a reduction of 22% compared to the reference example. Example 5 :

[0040] In this example the mix of raw materials is this time as described in table 6 below.

[0041] In this initial mixture, the natural mineral material "Luzenac" described in Example 2 above and a calcium and aluminum silicate from a "Hudson" quarry in Greenland were introduced as a reagent. Analysis shows that these two natural mineral materials correspond to the composition described in Table 6 below: [Table 6] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 H2O Name formula grams % weight Sand SiO 2 41,30 99,60 0,05 0,01 0,03 0,03 0,49 Iron oxide Fe 2 O 3 2,10 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Ti-oxide TiO 2 5,20 99,00 Limestone CaCO 3 431,30 0,54 0,08 0,19 0,01 55,33 0,27 0,05 44,11 "Hudson" 527,80 47,30 32,20 1,79 0,27 16,10 0,12 0,72 0,03 "Luzenac" 198,6 48,80 7,90 0,68 31,8 1,49 0,28 8,54 Final composition (% weight) 39,0 18,6 1,0 0,15 32,5 6,5 0,9 0,6

[0042] As in Example 1, the mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1430°C until the mixture is completely melted for a total duration of 2 hours 15 minutes including 90 minutes of refining. The quantity of CO 2 released this time is 190 grams, a reduction of 43% compared to the reference example. Example 6:

[0043] In this example the mix of raw materials is this time as described in table 7 below.

[0044] More specifically, in this example, the natural mineral materials described in Example 5 above were used as the mineral source of magnesium and calcium, as well as another natural mineral material of a magnesium silicate directly from a quarry located in Hermosillo, Mexico. [Table 7] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 H2O Name formula grams % weight Sand SiO 2 9,00 99,60 0,05 0,01 0,03 0,03 0,49 Iron oxide Fe 2 O 3 1,95 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Limestone CaCO 3 365,50 0,54 0,08 0,19 0,01 55,33 0,27 0,05 44,11 "Hermosillo" 81,70 40,50 0,43 0,06 0,08 46,50 0,60 0,24 11,54 0,12 "Hudson" 527,40 47,30 32,20 1,79 0,27 16,10 0,12 0,72 0,03 "Luzenac" 197,6 48,76 7,904 0,683 31,8 1,484 0,28 8,54 Final composition (% weight) 39,0 18,6 1,0 0,15 32,7 6,5 0,9 0,6

[0045] As in Example 1, the mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1430°C until the mixture is completely melted for a total duration of 2 hours 15 minutes including 90 minutes of refining. The quantity of CO 2 released this time is 170 grams, a reduction of 49% compared to the reference example. Example 7:

[0046] In this example the mix of raw materials is this time as described in table 8 below.

[0047] More specifically, in this example, the previously described mineral material from the "Hudson" quarry was used as the first source of calcium, and the previously described mineral material from the "Hermosillo" quarry as the second source of calcium. The additional source of magnesium is a periclase MgO. [Table 8] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 H2O Name formula grams % weight Sand SiO 2 75,00 99,60 0,05 0,01 0,03 0,03 0,49 bauxite Al 2 O 3 187,80 14,20 77,51 0,26 0,23 0,61 0,43 2,53 3,42 Iron oxide Fe 2 O 3 1,20 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 "Hermosillo" 572,00 40,50 0,43 0,06 0,08 46,50 0,60 0,24 11,54 0,12 "Hudson" 117,00 47,30 32,20 1,79 0,27 16,10 0,12 0,72 0,03 Periclase--CaO CaO-MgO 103,4 1,42 0,72 0,1 0,02 38,2 58,2 0,55 1,13 Final composition (% weight) 39,0 18,6 0,3 0,1 32,6 6,5 0,9 0,7

[0048] As in Example 1, the mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1430°C until the mixture is completely melted for a total duration of 2 hours 15 minutes including 90 minutes of refining. The quantity of CO2 released this time is 66 grams, a reduction of 80% compared to the reference example.

[0049] According to a second series of examples, different mixtures of raw materials are prepared in order to compare a mixture as currently used for the manufacture of rock wool for an identical final composition: [Table 9] Elements Weight percentage% SiO 2 39,5 CaO 17,4 MgO 10,6 Al 2 O 3 15,3 Fe 2 O 3 10,0 Na 2 O 4,1 K 2 O 0,1 TiO 2 1,7 Example 8 (prior art)

[0050] According to a reference example, a typical mineral composition of rock wool corresponding to the previous composition is synthesized, according to current techniques and the raw materials usually used.

[0051] Table 10 below gives the proportions of the different raw materials and the final composition of the mixture thus obtained: [Table 10] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 H2O Name formula grams % weight Sand SiO 2 358,40 99,60 0,05 0,01 0,03 0,03 0,49 bauxite Al 2 O 3 193,80 14,20 77,51 0,26 0,23 0,61 0,43 2,53 3,42 Iron oxide Fe 2 O 3 96,40 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Ti-oxide TiO 2 8,70 99,00 Na-carbonate Na 2 CO 3 65,80 58,32 0,10 41,49 Limestone CaCO 3 50,30 0,54 0,08 0,19 0,01 55,33 0,27 0,05 44,11 Dolomite CaMg(CO 3 ) 2 489,70 1,88 0,48 0,28 0,09 29,52 21,40 0,28 0,02 47,80 Final composition (% weight) 39,50 15,3 4,1 0,09 17,4 10,6 10,0 1,75

[0052] The mixture of raw materials is heated in air in a platinum crucible for 1 hour up to 1400°C and then until the mixture melts at 1430°C with a one-hour hold at the maximum temperature. The quantity of CO2 released is 283 grams. Example 9:

[0053] In this example the mix of raw materials is this time as described in table 11 below.

[0054] More specifically, in this example, a basalt rock from the Cluis quarry in France was used as a mineral source. This material is introduced directly, without any chemical transformation and after simple grinding to adapt its granulometry, mixed with the other constituents in proportions adjusted accordingly to obtain a molten mixture with a composition very close to that of the reference example 8. [Table 11] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 H2O Name formula grams % weight Basalt “Cluis” 841,10 45,92 14,83 2,58 0,39 12,77 7,61 11,48 1,39 2,85 bauxite Al 2 O 3 35,20 14,20 77,51 0,26 0,23 0,61 0,43 2,53 3,42 Iron oxide Fe 2 O 3 2,10 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Ti-oxide TiO 2 4,60 99,00 Na-carbonate Na 2 CO 3 27,60 58,32 0,10 41,49 Limestone CaCO 3 15,60 0,54 0,08 0,19 0,01 55,33 0,27 0,05 44,11 Dolomite CaMg(CO 3 ) 2 195,40 1,88 0,48 0,28 0,09 29,52 21,40 0,28 0,02 47,80 Final composition (% weight) 39,50 15,30 3,85 0,35 17,40 10,60 10,00 1,75

[0055] As in Example 1, the mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1430°C until the mixture is completely melted for a total duration of 2 hours 15 minutes including 90 minutes of refining. The quantity of CO2 released this time is 112 grams, a reduction of 61% compared to the reference Example 8. Example 10 :

[0056] In this example the mix of raw materials is this time as described in table 12 below.

[0057] In this initial mixture, the natural mineral material "Luzenac" described above was introduced as a reagent to replace the dolomite.

[0058] This material is directly introduced, without any chemical transformation and after simple grinding to adapt its granulometry, mixed with the other constituents in proportions adjusted accordingly to obtain a mixture with a composition very close to that of reference example 8. [Table 12] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 H2O Name formula grams % weight Sand SiO 2 210,10 99,60 0,05 0,01 0,03 0,03 0,49 bauxite Al 2 O 3 163,30 14,20 77,51 0,26 0,23 0,61 0,43 2,53 3,42 Iron oxide Fe 2 O 3 93,50 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Ti-oxide TiO 2 9,60 99,00 Na-carbonate Na 2 CO 3 68,30 58,32 0,10 41,49 Limestone CaCO 3 308,00 0,54 0,08 0,19 0,01 55,33 0,27 0,05 44,11 "Luzenac" 328 48,76 7,904 0,683 31,8 1,484 0,28 8,54 Final composition (% weight) 39,50 15,30 4,16 0,04 17,40 10,60 10,00 1,75

[0059] As in Example 1, the mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1430°C until the mixture is completely melted for a total duration of 2 hours 15 minutes including 90 minutes of refining. The quantity of CO2 released this time is 164 grams, a reduction of 42% compared to the reference Example 8. Example 11 :

[0060] In this example the mix of raw materials is this time as described in table 13 below.

[0061] In this initial mixture, another natural mineral material, a magnesium and iron silicate, directly from a quarry located in Carino, Spain, was introduced as a reagent to replace the dolomite. The oxide composition of this mineral material is given below. [Table 13] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 H2O Name formula grams % weight Sand SiO 2 255,30 99,60 0,05 0,01 0,03 0,03 0,49 bauxite Al 2 O 3 187,80 14,20 77,51 0,26 0,23 0,61 0,43 2,53 3,42 Iron oxide Fe 2 O 3 73,70 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Ti-oxide TiO 2 9,60 99,00 Na-carbonate Na 2 CO 3 68,00 58,32 0,10 41,49 Limestone CaCO 3 304,10 0,54 0,08 0,19 0,01 55,33 0,27 0,05 44,11 "Carino" 285,2 39,138 2,44 0,04 0,048 1,498 36,526 8,234 12,15 Final composition (% weight) 39,50 15,30 4,14 0,06 17,40 10,60 10,00 1,75

[0062] As in Example 1, the mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1430°C until the mixture is completely melted for a total duration of 2 hours 15 minutes including 90 minutes of refining. The quantity of CO2 released this time is 162 grams, a reduction of 43% compared to the reference Example 8. Example 12 :

[0063] In this example the mix of raw materials is this time as described in table 14 below.

[0064] In this initial mixture, the natural basaltic mineral material described in Example 9 above and the mineral compound Carino described in Example 11 were introduced as reagent. [Table 14] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 H2O Name formula grams % weight Basalt "Cluis 724,30 45,92 14,83 2,58 0,39 12,77 7,61 11,48 1,39 2,85 bauxite Al 2 O 3 54,30 14,20 77,51 0,26 0,23 0,61 0,43 2,53 3,42 Iron oxide Fe 2 O 3 4,20 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Ti-oxide TiO 2 5,60 99,00 Na-carbonate Na 2 CO 3 33,90 58,32 0,10 41,49 Limestone CaCO 3 142,90 0,54 0,08 0,19 0,01 55,33 0,27 0,05 44,11 "Carino" 137,70 39,14 2,44 0,04 0,05 1,50 36,5 8,23 12,15 Final composition (% weight) 39,50 15,30 3,90 0,30 17,40 10,60 10,00 1,75

[0065] As in Example 1, the mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1430°C until the mixture is completely melted for a total duration of 2 hours 15 minutes including 90 minutes of refining. The quantity of CO2 released this time is 77 grams, a reduction of 73% compared to the reference Example 8. Example 13:

[0066] In this example the mix of raw materials is this time as described in table 15 below.

[0067] More specifically, in this example, the natural mineral materials described in Example 12 above were used as the mineral source of magnesium and calcium, as well as another natural mineral material, magnesium silicate, directly from a quarry located in Hermosillo, Mexico. [Table 15] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 H2O Name formula grams % weight Basalt “Cluis” 447,00 45,92 14,83 2,58 0,39 12,77 7,61 11,48 1,39 2,85 bauxite Al 2 O 3 105,00 14,20 77,51 0,26 0,23 0,61 0,43 2,53 3,42 Iron oxide Fe 2 O 3 30,50 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Ti-oxide TiO 2 7,50 99,00 Na-carbonate Na 2 CO 3 47,00 58,32 0,10 41,49 "Hermosillo" 244,00 40,50 0,43 0,06 0,08 46,50 0,60 0,24 11,54 0,12 "Carino" 192,00 39,14 2,44 0,04 0,05 1,50 36,53 8,23 12,15 Final composition (% weight) 39,45 15,35 3,97 0,23 17,42 10,61 10,00 1,74

[0068] As in Example 1, the mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1430°C until the mixture is completely melted for a total duration of 2 hours 15 minutes including 90 minutes of refining. The quantity of CO2 released this time is 48 grams, a reduction of 83% compared to the reference Example 8. Example 14:

[0069] In this example the mix of raw materials is this time as described in table 16 below.

[0070] More specifically, in this example, the compounds described in Example 13 above were used as the mineral source, and sodium hydroxide was used as the sodium source. [Table 16] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 H2O Name formula grams % weight Basalt “Cluis” 447,00 45,92 14,83 2,58 0,39 12,77 7,61 11,48 1,39 2,85 bauxite Al 2 O 3 105,00 14,20 77,51 0,26 0,23 0,61 0,43 2,53 3,42 Iron oxide Fe 2 O 3 30,50 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Ti-oxide TiO 2 7,50 99,00 Na-hydroxide NaOH 35,50 77,49 22,51 "Hermosillo" 244,00 40,50 0,43 0,06 0,08 46,50 0,60 0,24 11,54 0,12 "Carino" 192 39,14 2,44 0,04 0,05 1,50 36,57 8,23 12,15 Final composition (% weight) 39,45 15,35 3,98 0,23 17,41 10,61 10,00 1,74

[0071] As in Example 1, the mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1430°C until the mixture is completely melted for a total duration of 2 hours 15 minutes including 90 minutes of refining. The quantity of CO2 released this time is 28 grams, a reduction of 90% compared to the reference Example 8.

[0072] According to a third set of examples, different mixtures of raw materials are prepared for the manufacture of rock wool, the final composition of which is in accordance with that described in the applications EP1667939B1 mentioned above, and as described below: [Table 17] Elements Weight percentage% SiO 2 43 CaO 14,3 MgO 1,6 Al 2 O 3 23,2 Fe 2 O 3 5,6 Na 2 O 6,8 K 2 O 3,9 TiO 2 0,8 Example 15 (prior art)

[0073] According to a reference example, a typical mineral composition of rock wool corresponding to the previous composition is synthesized, according to current techniques and the raw materials usually used.

[0074] Table 18 below gives the proportions of the different raw materials and the final composition of the mixture thus obtained: [Table 18] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 H2O Name formula grams % weight Phonolite (K,Na)AlSiO 4 615,00 61,07 18,06 6,77 5,54 1,08 0,28 2,69 0,49 Nepheline-sye (K,Na)AlSiO 4 55,70 56,25 24,02 8,06 8,51 1,26 0,01 0,13 bauxite Al 2 O 3 138,40 14,20 77,51 0,26 0,23 0,61 0,43 2,53 3,42 Iron oxide Fe 2 O 3 36,70 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Na-carbonate Na 2 CO 3 35,30 58,32 0,10 41,49 Limestone CaCO 3 210, 70 0,54 0,08 0,19 0,01 55,33 0,27 0,05 44,11 Dolomite CaMg(CO 3 ) 2 61,00 1,88 0,48 0,28 0,09 29,52 21,40 0,28 0,02 47,80 Final composition (% weight) 42,92 23,22 6,79 3,92 14,29 1,60 5,60 0,79

[0075] The mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1475°C until the mixture is completely melted for a total duration of 4 hours 30 minutes including 180 minutes of refining. The quantity of CO 2 released is 137 grams. Example 16 :

[0076] In this example the mix of raw materials is this time as described in table 19 below.

[0077] More specifically, in this example, a basalt rock from the Mendig quarry in Rhineland-Palatinate was used as a mineral source, the oxide composition of which is shown in Table 19 below. This material is introduced directly, without any chemical transformation and after simple grinding to adapt its granulometry, mixed with the other constituents in proportions adjusted accordingly to obtain a mixture with a composition very close to that of the reference example 15. [Table 19] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 H2O Name formula grams % weight Phonolite (K,Na)AlSiO 4 426,30 61,07 18,06 6,77 5,54 1,08 0,28 2,69 0,49 Nepheline-sye (K,Na)AlSiO 4 63,50 56,25 24,02 8,06 8,51 1,26 0,01 0,13 bauxite Al 2 O 3 130,50 14,20 77,51 0,26 0,23 0,61 0,43 2,53 3,42 Iron oxide Fe 2 O 3 17,20 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Na-carbonate Na 2 CO 3 36,80 58,32 0,10 41,49 Limestone CaCO 3 201,70 0,54 0,08 0,19 0,01 55,33 0,27 0,05 44,11 Basalt "Mendig" 247,00 45,89 15,65 4,79 3,90 10,13 5,51 9,84 2,37 0,56 Final composition (% weight) 42,92 23,22 6,81 3,90 14,29 1,60 5,60 1,25

[0078] The mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1475°C until the mixture is completely melted for a total duration of 4h30 including 180 min of refining. The quantity of CO2 released this time is 104 grams, a decrease of 24% compared to the reference example 15. Example 17 :

[0079] In this example the mix of raw materials is this time as described in table 20 below.

[0080] More specifically, in this example, the "Hudson" source described above was used as the mineral source. This material is introduced directly, without any chemical transformation and after simple grinding to adapt its particle size, mixed with the other constituents in proportions adjusted accordingly to obtain a mixture with a composition very close to that of the reference example 15. [Table 20] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 Name formula grams % weight Nepheline-sye (K,Na)AlSiO 4 405,00 56,25 24,02 8,06 8,51 1,26 0,01 0,13 Iron oxide Fe 2 O 3 53,80 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Na-carbonate Na 2 CO 3 56,00 58,32 0,10 41,49 Limestone CaCO 3 90,00 0,54 0,08 0,19 0,01 55,33 0,27 0,05 44,11 "Hudson" 420,00 47,30 32,20 1,79 0,27 16,10 0,12 0,72 0,03 Dolomite CaMg(CO 3 ) 2 69,00 1,88 0,48 0,28 0,09 29,52 21,40 0,28 0,02 47,80 Final composition (% weight) 42,88 23,30 7,36 3,57 14,31 1,57 5,60 0,04

[0081] The mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1475°C until the mixture is completely melted for a total duration of 4h30 including 180 min of refining. The quantity of CO2 released this time is 96 grams, a reduction of 30% compared to the reference example 15. Example 18 :

[0082] In this example the mix of raw materials is this time as described in table 21 below.

[0083] In this initial mixture, the natural mineral materials "Hermosillo" and "Hudson" described above were introduced as reagents. [Table 21] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 H2O Name formula grams % weight Nepheline-sye (K,Na)AlSiO 4 267,00 56,25 24,02 8,06 8,51 1,26 0,01 0,13 Iron oxide Fe 2 O 3 53,80 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Na-carbonate Na 2 CO 3 88,00 58,32 0,10 41,49 "Hermosillo" 76,00 40,50 0,43 0,06 0,08 46,50 0,60 0,24 11,54 0,12 "Hudson" 520,00 47,30 32,20 1,79 0,27 16,10 0,12 0,72 0,03 Dolomite CaMg(CO 3 ) 2 69,00 1,88 0,48 0,28 0,09 29,52 21,40 0,28 0,02 47,80 Final composition (% weight) 42,88 23,23 8,28 2,43 14,30 1,60 5,67 0,04

[0084] The mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1475°C until the mixture is completely melted for a total duration of 4h30 including 180 min of refining. The quantity of CO2 released this time is 78 grams, a reduction of 43% compared to the reference example 15. Example 19 :

[0085] In this example the mix of raw materials is this time as described in table 22 below.

[0086] In this initial mixture, the natural mineral materials "Hermosillo" and "Hudson" described above were introduced as reagents. [Table 22] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 H2O Name formula grams % weight Nepheline-sye (K,Na)AlSiO 4 267,00 56,25 24,02 8,06 8,51 1,26 0,01 0,13 Iron oxide Fe 2 O 3 53,80 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Na-hydroxide NaOH 66,00 77,49 22,51 Hermosillo 76,00 40,50 0,43 0,06 0,08 46,50 0,60 0,24 11,54 0,12 Hudson 520,00 47,30 32,20 1,79 0,27 16,10 0,12 0,72 0,03 Dolomite CaMg(CO 3 ) 2 69,00 1,88 0,48 0,28 0,09 29,52 21,40 0,28 0,02 47,80 Final composition (% weight) 42,88 23,23 8,26 2,43 14,29 1,60 5,67 0,04

[0087] The mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1475°C until the mixture is completely melted for a total duration of 4h30 including 180 min of refining. 42 g of CO2 are released during the melting of the raw materials, a reduction of 69% compared to the reference example 15. Example 20:

[0088] In this example, the mixture of raw materials is this time as described in Table 23 below. In this initial mixture, the natural mineral materials “Hermosillo”, “Hudson” and “Basalt Mendig” described previously were introduced as reagents. [Table 23] Bath SiO 2 Al 2 O 3 Na 2 O K 2 O CaO MgO Fe 2 O 3 TiO 2 CO2 H2O Name formula grams % weight Nepheline-sye (K,Na)AlSiO 4 38,00 56,25 24,02 8,06 8,51 1,26 0,01 0,13 Iron oxide Fe 2 O 3 27,30 1,04 0,18 0,81 0,01 0,23 0,22 97,11 0,45 Na-hydroxide NaOH 85,80 77,49 22,51 "Hermosillo" 55,00 40,50 0,43 0,06 0,08 46,50 0,60 0,24 11,54 0,12 "Hudson" 565,00 47,30 32,20 1,79 0,27 16,10 0,12 0,72 0,03 Basalt "Mendig" 258,00 45,89 15,65 4,79 3,90 10,13 5,51 9,84 2,37 0,56 Final composition (% weight) 42,96 23,17 9,23 1,49 14,32 1,53 5,61 0,64

[0089] The mixture of raw materials is introduced hot into a platinum crucible in a flame furnace (air-gas or oxy-gas combustion) at 1475°C until the mixture is completely melted for a total duration of 4h30 including 180 min of refining. The quantity of CO2 released this time is 6 grams, a reduction of 95% compared to the reference example 15.

[0090] The advantages and quality of the glass obtained from the molten glass baths according to examples 1 (reference comparison) to 7 above are indicated in table 24 below, in which different assessment criteria obtained according to the following measurements have been reported: 1) Yield This is the ratio between the quantity of wool produced and the quantity of raw materials put into the furnace. The higher this ratio, the higher the quantity of wool that can be produced and the lower the gas emissions (CO 2 , H 2 O). 2) Quantity of sand: this is the quantity of sand used compared to reference example 1 (as a percentage of weight saved).In addition to the health considerations related to excessive sand consumption (silicosis), reducing the amount of sand used in favor of other mineral materials such as natural silicates allows reducing the energy used to melt the bath, the most refractory raw material in the bath generally being silica or the alumina carrier (bauxite) in examples 15 to 20. 3°) Energy consumed: this is the amount of energy saved compared to the reference example 1 (in percentage). This measurement corresponds to the energy required to melt the mixture of raw materials corresponding to each example. 4°) Quality of refining (or bubble rate): . The number of bubbles per kilogram of glass melted at 1500°C for 120 minutes is measured. The higher this index, the better the refining quality. ***: number of bubbles example / number of bubbles reference example 1 < 100% ****: number of bubbles example / number of bubbles reference example 1 < 50% 5°) Homogeneity in SiO 2 : The quality index is proportional to the SiO 2 homogeneity (as measured by microprobe / EDS) of the glass melted at 1500°C for 120 min. The homogeneity is measured by a series of measurements of the quantity of SiO 2 at different points of the mineral wool fibers and a standard deviation is then determined. ** : SiO 2 standard deviation (measured by microprobe / EDS) >0.5% *** : SiO 2 standard deviation (measured by microprobe / EDS) between 0.1 and 0.5% **** : SiO 2 standard deviation (measured by microprobe / EDS) <0.1%. [Table 24] Ex. 1 Ex.2 Ex.3 Ex.4 Ex.5 Ex.6 Ex.7 Yield (%) 76 79 79 78 83 85 86 Amount of sand saved (%) Ref. 25 34 18 88 97 78 Energy saved (%) Ref. 3 5 4,5 10 12 36

[0091] Comparison of the above results shows that examples 2 to 7 according to the invention show quality indices overall superior to reference examples 1 and 6.

[0092] Examples 5 and 6 according to the invention, in which a source of calcium consisting of a natural mineral calcium silicate and a source of magnesium consisting of a natural mineral magnesium silicate are used as raw materials for said melt in combination, even appear particularly advantageous, according to all the criteria reported in the preceding table 9.

[0093] The advantages and quality of the mineral wool obtained from the molten baths according to examples 15 (reference comparison) to 20 above are indicated in table 25 below, in which different assessment criteria obtained according to the following measurements have been reported: [Table 25] Ex.15 Ex.16 Ex.17 Ex.18 Ex.19 Ex.20 Yield (%) - 89 91 93 95 97 Amount of sand saved (%) Ref. 30 34 56 100 100 Energy saved (%) Ref. 3 6 10 15 12 Refining Ref. *** *** **** *** Homogeneity in SiO 2 ** *** *** *** **** ****

[0094] Comparison of the above results shows that examples 16 to 20 according to the invention show quality indices which are generally higher than reference example 15.

Claims

1. A method for manufacturing a mineral wool having a target composition, comprising the melting of a mixture of raw materials constituting a molten bath, said target composition meeting the following criteria, in weight percentages: SiO2: between 30 and 50%, Na2O: between 0 and 20%, CaO: between 6 and 35%, MgO: between 1 and 15%, CaO+MgO: between 11 and 40% in total, Al2O3: between 10 and 27%, K2O: between 0 and 15%, Iron oxide: between 0.5 and 15%, other oxide(s): between 0 and 5% in total, preferably less than 3%, the remainder consisting of unavoidable impurities, said method being characterized in that it comprises the following steps: a) selecting the raw materials of said molten bath from, at least: - a silicon source, in particular chosen from silica, a basalt, recycled mineral fibers or mixtures thereof, - optionally at least one sodium source preferably selected from sodium hydroxide NaOH, sodium carbonate Na2CO3 or a mixture of sodium hydroxide NaOH and calcium carbonate Na2CO3, - at least one calcium source selected from a natural mineral calcium silicate comprising, in percentage by weight, more than 30% SiO2 and more than 10% CaO, CaO and SiO2 together representing more than 70% of the weight of said silicate, and / or - at least one magnesium source selected from a natural mineral magnesium silicate comprising, in percentage by weight, more than 30% SiO2 and more than 10% MgO, MgO and SiO2 together representing more than 70% of the weight of said silicate, said calcium and / or magnesium sources being natural mineral materials, that is to say unprocessed mineral materials originating from a natural geological environment, - optionally, limestone CaCO3 - optionally a complementary source of aluminum such as bauxite, - optionally a complementary source of magnesium such as a magnesium oxide, - optionally a complementary source of iron such as an iron oxide, b) the composition of said sources of calcium and / or magnesium and / or natural aluminum is determined, c) on the basis of said composition(s) determined according to point b), determining the necessary quantities of said raw materials to obtain a mixture of said target composition, d) mixing said materials according to said quantities, e) melting and fiberizing said mixture and cooling same under the conditions that make it possible to obtain said mineral wool.

2. The method according to the preceding claim, wherein said calcium source is a natural mineral calcium silicate comprising, in percentage by weight, more than 30% SiO2 and more than 15% CaO, CaO and SiO2 together representing more than 70% of the weight of said silicate, preferably more than 80% of the weight of said silicate.

3. The method according to one of the preceding claims, wherein said magnesium source is a natural mineral magnesium silicate comprising, in percentage by weight, more than 30% SiO2 and more than 15% MgO, MgO and SiO2 together representing more than 70% of the weight of said silicate, preferably more than 80% of the weight of said silicate.

4. The method according to claims 2 and 3, wherein a calcium source is used which is a natural mineral calcium silicate comprising, in percentage by weight, more than 30% SiO2 and more than 10% CaO, preferably more than 15% CaO, CaO and SiO2 together representing more than 70% of the weight of said silicate, preferably more than 80% of the weight of said silicate and a magnesium source which is a natural mineral magnesium silicate comprising, in percentage by weight, more than 30% SiO2 and more than 10% MgO, preferably more than 15% MgO, MgO and SiO2 together representing more than 70% of the weight of said silicate, preferably more than 80% of the weight of said silicate.

5. The method according to one of the preceding claims, wherein said magnesium source is a natural mineral material corresponding to the following composition, in percentages by weight: - SiO2: between 40 and 55%, preferably between 45 and 50%, - Al2O3: between 0 and 10%, for example between 1 and 10%, - MgO: between 20 and 40%, preferably between 25 and 35%, - MgO and SiO2 cumulatively representing at least 70%, or even at least 75%, - Fe2O3: between 0 and 4%, for example between 1 and 3%, - less than 5% of other oxides, preferably less than 3% of other oxides, - optionally water.

6. The method according to one of the preceding claims, wherein said magnesium source is a natural mineral material corresponding to the following composition, in percentages by weight: - SiO2: between 55 and 70%, preferably between 58 and 65%, - Al2O3: between 0 and 10%, for example between 1 and 10%, - MgO: between 20 and 40%, preferably between 25 and 35% - MgO and SiO2 cumulatively representing at least 80%, preferably at least 85%, or even at least 90%, - Fe2O3: between 0 and 4%, for example between 0.5 and 2%, - less than 5% of other oxides, preferably less than 3% of other oxides, - optionally water, in particular present in said source in the form of hydroxide(s), preferably in an amount of less than 20% and in particular between 5 and 15%.

7. The method according to one of claims 1 or 2, wherein said magnesium source is a natural mineral material corresponding to the following composition, in percentages by weight: - SiO2: between 30 and 50%, preferably between 35 and 45%, - Al2O3: between 0 and 10%, for example between 1 and 5%, - MgO: between 25 and 45%, preferably between 30 and 40%, - MgO and SiO2 cumulatively representing at least 70%, or even at least 75%, - Fe2O3: between 0 and 10%, for example between 5 and 10%, - less than 5% of other oxides, preferably less than 3% of other oxides - optionally water, in particular present in said source in the form of hydroxide(s), preferably in an amount of less than 20% and in particular between 5 and 15%.

8. The method according to one of the preceding claims, wherein said calcium source is a natural mineral material corresponding to the following composition, in percentages by weight: - SiO2: between 30 and 55%, preferably between 35 and 50%, - CaO: between 35 and 55%, preferably between 40 and 50%, - CaO and SiO2 cumulatively representing at least 80%, or even at least 85%, - Fe2O3: between 0 and 4%, for example between 0.1 and 0.5%, - Al2O3: between 0 and 5%, for example between 0.5 and 2%, - CO2: between 0 and 20%, in particular between 5 and 15%, - less than 5% of other oxides, preferably less than 3% of other oxides.

9. The method according to one of the preceding claims, wherein said calcium source is a natural mineral material corresponding to the following composition, in percentages by weight: - SiO2: between 40 and 55%, preferably between 40 and 50%, - CaO: between 10 and 20%, - CaO and SiO2 cumulatively representing at least 55%, or even at least 60%, - Al2O3: between 10 and 40%, for example between 25 and 35%, - Fe2O3: between 0 and 4%, for example between 0.1 and 1%, - less than 5% of other oxides, preferably less than 3% of other oxides.

10. A method wherein at least one magnesium source as described in one of claims 5 to 7 and at least one calcium source as described in one of claims 8 or 9 are used as raw materials.

11. A method wherein the two calcium sources as described in claims 8 and 9 are used as raw materials.

12. The method according to one of the preceding claims, wherein said source of calcium is a natural mineral material chosen from basaltic rocks.

13. The method according to the claim 1, wherein a magnesium and / or calcium source is a natural mineral material corresponding to the following composition, in percentages by weight: - SiO2: between 40 and 60%, preferably between 42 and 55%, - CaO: between 5 and 25%, preferably between 10 and 20%, - MgO: between 3 and 20%, preferably between 5 and 15%, - Al2O3: between 0 and 20%, for example between 5 and 15%, - Fe2O3: between 0 and 20%, for example between 5 and 15%, - less than 5% of other oxides, preferably less than 3% of other oxides, - between 0 and 5% water, in particular present in said source in the form of hydroxide(s).

14. A method wherein at least one magnesium source as described in one of claims 5 to 7 is used as the raw material, and a natural mineral material chosen from basaltic rocks as described in one of claims 12 or 13 is used as a magnesium and / or calcium source.

15. A method wherein at least one calcium source as described in one of claims 8 or 9 is used as raw material, preferably the two calcium sources as described in claims 8 and 9, and a natural mineral material chosen from basaltic rocks as described in one of claims 12 or 13 is used as a magnesium and / or calcium source.

16. The method according to one of the preceding claims, wherein recycled mineral fibers are introduced into the molten bath.

17. The method according to the preceding claim, wherein the recycled mineral fibers represent between 1 and 50% of the total weight of the molten bath, preferably between 3 and 40% of the total weight of the molten bath.

18. The method according to one of the preceding claims, wherein said target composition satisfies the following criteria, in percentages by weight: SiO2: between 30 and 50%, preferably between 35 and 45%, Na2O: between 0 and 10%, preferably between 0.4 and 7%, CaO: between 10 and 35%, preferably between 12 and 25%, MgO: between 1 and 15%, preferably between 5 and 13%, CaO+MgO: between 11 and 40% in total, Al2O3: between 10 and 27%, K2O: between 0 and 2%, preferably between 0 and 1%, Iron oxide: between 0.5 and 15%, preferably between 3 and 12% other oxide(s): between 0 and 5% in total, preferably less than 3%, the remainder consisting of unavoidable impurities.

19. The method according to the preceding claim, wherein said target composition satisfies the following criteria, in percentages by weight: SiO2: between 30 and 50% Al2O3: between 10 and 20% CaO+MgO: between 20 and 40% in total Na2O+K2O: between 1 to 10%20. The method according to one of the claims 1 to 18, wherein said target composition satisfies the following criteria, in percentages by weight: - SiO2between 39 and 50%- Al2O3between 16 and 27%, preferably between 20 and 25%- CaObetween 6 and 20%- MgObetween 1 and 5%- Na2Obetween 0 and 20%, preferably between 3 and 10%- K2Obetween 0 and 15%, preferably between 2 and 10%- P2O5between 0 and 3%- Fe2O3between 1.5 and 15%- B2O3between 0 and 2%- TiO2between 0 and 2%.

21. The method according to the preceding claim, wherein said target composition satisfies the following criteria, in percentages by weight: - less than 9% in total of Na2O and K2O (Na2O+K2O < 9%) and / or - less than 20% in total of MgO and CaO (MgO+CaO < 20%)22. A mixture of raw materials as described in one of the preceding claims, comprising: - a silicon source, in particular chosen from silica, a basalt, recycled mineral fibers or mixtures thereof, - optionally at least one sodium source preferably selected from sodium hydroxide NaOH, sodium carbonate Na2CO3 or a mixture of sodium hydroxide NaOH and calcium carbonate Na2CO3, - at least one calcium source selected from a natural mineral calcium silicate comprising, in percentage by weight, more than 30% SiO2 and more than 10% CaO, CaO and SiO2 together representing more than 70% of the weight of said silicate, and / or - at least one magnesium source selected from a natural mineral magnesium silicate comprising, in percentage by weight, more than 30% SiO2 and more than 10% MgO, MgO and SiO2 together representing more than 70% of the weight of said silicate, said calcium and / or magnesium sources being natural mineral materials, that is to say unprocessed mineral materials originating from a natural geological environment, - optionally, limestone CaCO3 - optionally a complementary source of aluminum such as bauxite, - optionally a complementary source of magnesium such as a magnesium oxide, - optionally a complementary source of iron such as an iron oxide.