MXPA98003454A - Methods to manufacture particulates fused by porfusion to the fl - Google Patents

Abstract

Methods are described for producing bulky, particulate material, which includes generally ellipsoidal, solid particles. Irregularly shaped feed particles with average particle sizes of up to 25 microns are dispersed based on the volume in at least a portion of a combustible gas mixture by the application of force and / or fluidizing agents. The fuel mixture with particles in suspension is then released, while controlling the agglomeration or reagglomeration of the particles, to at least one front part of the flame. There, the mixture and the suspended particles are distributed evenly across the surfaces and pass through the front of the flame with a high concentration of particles in the mixture. In this way the front part of the flame and the resulting flame with the suspended particles are located in at least one area "free of the wall". In such an area the flame can expand while the particles are maintained in dispersion, with controlled and highly efficient application of heat energy. At least partial fusion occurs within at least the surface of the particles at high efficiencies at high thermal efficiencies, while the agglomeration of the particles during the melt is inhibited.

Description

METHODS TO MANUFACTURE PARTICLES FUSED BY FUSION TO THE FLAME " TECHNICAL FIELD The present invention relates to improved flame fusion methods for manufacturing particulate, substantially glassy, at least partially fused products. Preferred embodiments of the invention include methods for manufacturing generally ellipsoidal particulates by at least partially direct fusion of economically feasible yield trace particulars while controlling the undesirable formation of elongated product particles from agglomerated feed particles.

BACKGROUND OF THE INVENTION The techniques for melting or softening small feed particles under controlled conditions to make particulate products generally ellipsoidal are known. Examples include atomization, flame fusion and direct fusion. The atomization involves melting an iriada of particles of feeding to turn them into a voluminous liquid glass. A thin stream of such glass is atomized through contact with a jet of disruptive air. This divides the stream into thin droplets. They keep one away from the other and other objects until they cool and solidify. They are then recovered as amorphous particles, generally ellipsoidal, substantially discrete or separated vitreous. In fire-polishing, vitreous solid-shaped, separate-shaped, solid feed particles are heated to a soft or molten condition while dispersing and suspending in a hot gaseous medium. The surface tension forms the particles in ellipsoidal forms. By keeping them suspended in colder gases until they reach their cooling temperatures, the particles recover as vitreous ellipsoids generally separated, solid. The atomization and polishing by glass fire can also be described as indirect methods. These feedstocks have been formulated from raw materials for glass making which are melted and homogenized in the form of a bulky liquid before entering the ellipsoid formation stage. Accordingly, in the indirect methods, the individual chemical identities of the raw materials for glassmaking have been joined in an average composition which is uniformly present in the respective alipsoids thus produced. In direct fusion, somewhat similar to fire polishing, it uses food particles with irregular shapes that are not vitreous, or are at least not completely vitreous.

They can be discrete solid particles and / or adherent groups of particles. These groups are sometimes called groups or agglomerates. Warmed while suspended and dispersed in a hot gaseous medium, the feed particles soften or melt and take the form of a melt, generally ellipsoidal forms, which are then cooled, frozen and recovered at least partially, but not completely , in a vitreous state. Unlike direct melting, fire polishing typically utilizes solid feed particles that are in a relatively high or full vitreous or amorphous state. At some point in their process, they exist in voluminous liquid form. In direct fusion, feed particles that are not completely vitreous or amorphous, and are often non-vitreous minerals and undergo direct conversion to vitreous form, or at least to a more closely vitreous and amorphous form, at a stage of formation of ellipsoids, without previous conversion to the voluminous liquid form. As used herein, fusion to the flame involves at least the formation of substantially vitreous particulate products, partially fused by direct melting or fire-polishing of solid feed particles. As a feed to a fusion zone, they can have physical states that vary from completely crystalline to completely vitreous and amorphous.

In direct fusion, each particle of ellipsoidal product can be formed by melting a separate feed particle or by melting a group of several mutually adherent feed particles described herein as agglomerates. These product particles, respectively and generally show the variable chemical compositions of the different particles and / or the average chemical compositions of the groups of agglomerated particles, of which the ellipsoids are respectively formed, except that there may be relatively small losses of the ingredients through high temperature volatilization. Therefore, the direct melt products do not necessarily have a more uniformly particle-like particle composition than expected from particles produced from bulky liquid glass by atomization or fire polishing. In the known flame fusion processes, various forms of equipment have been used, as well as different forms of feeding and fusion methodology. For example, since 1935, as described in US Pat. No. 1,995,803 to Gilbert, on page 1, column 1, lines 31-32 and column 2, lines 33-41, which in order to generate well-formed pelleted products , the feed particles must be positively dispersed in a gas containing fuel and / or oxygen that is fed to a burner that heats the melting zone, and this can be done upstream of the burner. Gilbert also describes, on page 2, column 1, lines 1-8 that the subsequent heating and expansion of the gases provides an additional dispersive effect. This patent does not describe the combustion chamber geometry of Gilbert. However, his later US Patent No. 2,044,680, on page 3, column 1, lines 2 and 5 twice describes his chamber with "confinement" surfaces. As a further example, Garnier, in U.S. Patent No. 4,778,502, in column 2, lines 41-45, describes the production of hollow microspheres from particulate feeds. At least 90 percent of the feed particles have particle sizes less than 20, and preferably less than 10 microns. To combat the agglomeration of the feed, which is recognized as an element that makes the production of microspheres of small dimensions difficult, the patent proposes to pre-treat the feed by distributing on its particle surfaces a small amount of a "fluidizing agent" preferably alkanolamines. See column 2, lines 46-58. The feed, milled in ball with the agent, can be dispersed in gases, as taught in column 6, lines 19-35 and column 4, lines 50-55, and can then be fused with the help of any of two types of burners. Each of these, as described in column 4, line 64 to column 5, line 43 in figures 1 and 2, has a combustion chamber which is restricted in cross section relative to a downstream expansion chamber. The combustion chamber, which includes fuel orifices 20 and air holes 23, 24 has an equally restricted cross-sectional extension with a surface with a refractory part 25 (Figure 1) or a wall 27 of metal cooled with liquid (Figure 1). 2). In the burner of Figure 1, the feed dispersion is projected towards the combustion gases exiting from the front end or the outlet of the combustion chamber through one or more radially oriented injection orifices 30, 31. In the burner of Figure 2, the feed dispersion is projected into the combustion chamber through an axial tube 17 at the rear end of the burner. In British Patent No. 2,178,024 on page 5, line 33 to page 6, line 4, Mouligneau et al., Describe that it is more desirable to use a well-dispersed feed in combustible gases. They describe the propulsion of a feed gas stream entrained through a conduit leading to the combustion chamber and forcing a second gas stream transversely in the first gas stream through an orifice in the conduit wall, to generate forces that promote intimate mixing. In addition, on page 2, lines 6-8, these patents describe a tendency of the feed particles to agglomerate and / or stick to the walls of the melting chamber. They attribute this problem to excessive heating of the feed during melting. As a solution, they propose on page 2, lines 15-20 to provide a flowing gaseous sleeve. It surrounds the stream of fuel gases to the flame that contains the dispersed feed particles. The sleeve should improve yields with high quality spheres by keeping the feed particles completely wrapped around the flame, allowing rapid heating of the feed, adding kinetic energy to the feed and producing particles while they remain dispersed and promotes separation fast of the product particles of the combustion chamber, cooling of the walls of the combustion chamber and in this way agglomeration and adhesion tendencies are reduced. See page 2, lines 22-31. Morishita et al. , in the published Japanese patent application HEI 2 [1990] 59416, published on February 28, 1990, describes the direct fusion of silica with particle sizes of less than 10 microns. Severe problems of agglomeration of the feed materials in the flame during melting and adherence of the particles to the furnace wall are mentioned. They suggest that agglomeration can be avoided by working with plasma induction at temperatures that exceed those of a usual melting furnace. However, they explain that this method is not suitable for mass production and has a poor efficiency in terms of energy. Morishita et al propose solving these problems by using a feed powder produced by a jet mill at a particle size of less than micrometers, followed by direct melting in a melting furnace with a flame of flammable gas with oxygen (for example oxygen-propane). ). The supply is supplied to a burner that has a dust discharge hole in the center, and an opening for the gas flame in the central axis. The thermal load of the burner and the thermal load per unit volume of the furnace are respectively in the ranges of 100,000-20,000 kcal / H and less than 2,000,000 kcal / m 3H. It is said that higher thermal loads lead to the agglomeration of the feed, and that lower thermal loads of the burner are said to lead to poor quality products. Further reviewed the work described above, the previous inventors and another, in the published Japanese patent application HEI 2 [1990] 199013 published on August 7, 1990, recognize that it has been proved that it is difficult for them to realize fine spheroidal silica with high performance by direct reduction of fine silica with thermal load control. However, they suggest that this problem can be solved by supplying a cooling gas and adjusting the flame generation area. When working with a melting furnace with a flammable oxygen-gas flame again, and with a feed of less than 10 micrometers which is dispersed in the carrier gas and fed to the center of the flame, they are injected by air in cooling gas perpendicular to the flame or are introduced through a ring. This is done in a selected position downstream of a burner and is said to effectively eliminate the generation of flame, that is, it eliminates the flame. By changing the position and other aspects of the introduction of the cooling / quenching gas, it is said that the residence time of the silica in the flame can be adjusted, the grain growth can be prevented by agglomeration in the flame and recover the high yields of small particles . In the Japanese patent application published No. HEI 4 [1992] -147923, "Manufacturing Method of Spherical Microparticles", by T. Koyama, et al.. , published on May 21, 1992, the inventors suggest, apparently in an attempt to recover very small products, crush the raw material to a particle size in the range of 0.1 to 1 micrometer. However, it appears that the melting process used suffers from a certain considerable agglomeration of the molten or soft particles. Regardless of the progress made by previous researchers in the art, there seems to be a need for, and an opportunity to provide, additional improvements in the performance and energy efficiency of the flame fusion processes in order to produce ellipsoidal particles. generally very thin. This seems especially valid in relation to the mass production of products, from feeds in the particle sizes that vary with 50 percent, (average particle size) of up to about 25, up to about 20, up to about 15 and up about 10 microns, or with 90 percent up to about 60, up to about 40, and up to about 30, in volume. In the production of these products, increasing production speeds presents the tendency to produce agglomeration and allow the growth of particle size during melting, while avoiding agglomeration at the expense of energy efficiency. The present invention seeks to satisfy the need established above. This objective is met, and is solved in part, by the development of products and methods described below. Description of the Invention in the Form of Volume The present invention includes a method for the production, in bulk, of particulate material, including product particles, generally ellipsoidal, solid, which comprise dispersing in gaseous suspension, in at least a portion of a combustible gas mixture, solid feed particles which include about 60 to 100% by weight of irregularly shaped particles of at least one fed material having a volume average particle size of up to about 25 micrometers, and is at least partially convertible to generally ellipsoidal particles by heating the material while flowing in suspension in the hot gases generated by the combustion of the gas mixture. The method further includes releasing the fuel mixture and the feed particles suspended to the front of a flame in which the mixture is incinerated, the concentration of the feed particles in the mixture being in the range of about 0.2 to about 2 Kilograms. per kilograms of mixture; maintaining the front of the flame and at least a substantial portion of the resulting flame in a free zone of the wall, which extends downstream of the front; maintaining at the same time the suspended particles in a dispersed condition, heating the particles with the heat transferred to them by igniting the combustible mixture, thereby producing at least partial melting of the irregularly shaped particles within at least their surfaces; and expanding the igniting gases and causing the particles to melt in sufficient amounts to produce a bulky, at least partially fused particulate product, wherein approximately 15 to 100% by volume of the bulked particulate product is fused to product particles. , discrete, generally ellipsoidal. The total amount of heat used for heating, including preheating, if any, of the feed particles, any other components of the fuel mixture and the fuel mixture itself for the melting of the particles, for expansion, if there is, and for heat losses, it is restricted to an amount in the range of about 278 to about 13,889 kilocalories per kilogram of product particles, generally ellipsoidal produced. The invention further includes a method for the production, in bulk, of particulate material, including generally ellipsoidal, solid product particles, comprising providing solid feed particles including about 60 to 100% by weight of irregularly shaped particles of at least a fed material having a volume average particle size of up to about 25 microns. The fluidizing agent and / or the force to be applied to the feed particles for the dispersion of the feed particles in gaseous suspension in at least a portion of a fuel gas mixture. Releasing at the same time mixes fuel and feed particles suspended to the front of a flame in which the mixture is incinerated, inhibit the agglomeration and / or reaglomeration of the suspended feed particles and the particles present in the suspension are distributed through from the front of the flame. The front of the flame and at least a substantial portion of the resulting flame is maintained in a free zone of the wall, which extends downstream of the front. While maintaining the feed particles suspended in a dispersed condition, heat the dispersed feed particles with heat transferred to them by igniting the fuel mixture, thereby reducing at least the partial melting of the irregularly shaped particles within at least its surfaces. Applying enough fluidizing agent and / or force in the dispersion operation, sufficiently inhibiting the agglomeration and / or reaqlomeration; the ignition qases in the free zone of the wall are sufficiently expanded and a sufficient weight ratio of the feed particles is established per unit of heat released in that zone to produce at least one voluminous, partially fused particulate product. Approximately 15 to 100% by volume of the voluminous particulate product fused is discrete product particles, generally ellipsoidal. The excess, if any, of the indicated 90 percent particle size of a product sample that has been vigorously stirred in liquid, minus the primary particle size of 90 percent of a sample of the fed, of which the product has been prepared and has been vigorously stirred in liquid, is in the range of up to about 30% of the primary particle size, on a weight basis or, after making appropriate corrections for any voids that may be present in the particles of the product, or a basis in volume. The invention also comprises a method for the production, in bulk, of particulate material, including generally ellipsoidal, solid product particles, comprising dispersing in gaseous suspension, in at least a portion of a combustible gas mixture, solid feed particles which include about 60 to 100% by weight of irregularly shaped particles of at least one fed material having a volume average particle size of up to about 25 microns, * which has a tendency to agglomerate and form lumps when groups of particles they are subjected to compaction forces when they are at rest and / or in motion, and are at least partially convertible to generally ellipsoidal particles by heating the material, while it flows in suspension in the hot gases generated by the combustion of the gas mixture . Applying to the feed particles a quantity of fluidizing agent and / or an amount of force sufficient to disperse the feed particles in the gas mixture or a portion thereof, so that the difference in particle size of 90 percent indicated in the primary and secondary samples of the feed particles that have been taken respectively before and after the dispersion, the sample of primary particle size has been vigorously stirred in liquid before measuring its particle size, * it is in the range up to about 20% of the primary fed particle size, based on one volume. After dispersing the feed particles in the gas mixture or a portion thereof, and while releasing the fuel mixture and the feed particles suspended to the front of a flame, in which the mixture is incinerated, inhibit the agglomerating and / or reagglomerating the suspended feed particles and distributing the particles present in the suspension substantially uniformly through the front of the flame, the concentration of the feed particles in the mixture is in the range of about 0.05 up to approximately 2 pounds per pound of mixture. In addition, maintain the front of the flame and at least a substantial portion of the resulting flame in a free zone of the wall, which extends downstream from the front, while maintaining the suspended feed particles in dispersed condition . Heat the dispersed feed particles with heat transferred to them by igniting, and while the particles enter, the fuel mixture at a melting temperature in the range of about 500 to about 2500 degrees centigrade, expanding the combustion gases and producing the fusion of the feed particles introduced in sufficient quantities to produce a bulky, at least partially fused particulate product, wherein approximately 15 to 100% by volume of the voluminous particulate product fused is of discrete or discrete product particles, generally ellipsoidal. In this method, the total amount of heat used for heating, including the preheating, if any, of the feed particles, of any other components of the fuel mixture and of the fuel mixture itself, is restricted for melting the particles, for expansion, if any, and for heat losses, by restricting the amount in the range from about 278 to about 13,889 kilocalories per kilogram of product particles, generally ellipsoidal, produced. Another method for the production, in bulk, of particulate material, including generally ellipsoidal, solid particles, comprises dispersing feed particles in irregularly dispersed conditions, which are substantially composed of one or more silicas and / or silicates that are found naturally, are at least partially convertible to generally ellipsoidal particles by heating the material while it is flowing in suspension in the hot gases generated by the combustion of the gas mixture, have an average particle size in volume in the range of up to about 15 micrometers, and include enough volatile material in the form of combined or dissolved water to generate void in at least a portion of the fused product particles. While maintaining the feed particles in a dispersed condition, heat the feed particles sufficiently to produce at least one bulky, partially fused particulate product having a volume average particle size in the range of up to about 15 micrometers, containing about 15 to 100% by volume of product particles, discrete, generally ellipsoidal, melted, which are substantially vitreous, and that at least the surface portions of the particles are amorphous, and includes about 1% to about 20% of the void volume, based on the volume of the product particles. The present invention also includes a composition of matter comprising solid particles wherein at least a portion of the solid particles are generally ellipsoidal particles which are substantially vitreous and which at least the surface portions of the particles are amorphous. At least a portion of the solid particles respectively constitute the particles of the product produced by the at least partial melting of the feed particles, while they are flowing in suspension in the hot combustion gases, the feed particles have volatile material which fluctuates in an amount of about 1 to about 25% by weight based on the weight of the particles fed. The portion of solid particles mentioned above are also respectively derived from, and have chemical compositions that correspond substantially to the chemical composition of, one or more silicas and / or silicates present in mineral deposits found in nature, except that the amount of Volatile matter in the particles of the product may differ from the content of volatile matter of the corresponding mineral found in nature. The particles have a color Quest 457 nanometer brightness of at least about 60, have a volume average particle size in the range of up to about 15 microns, and include at least 1% up to about 20% of the void volume, based on volume of the product particles. In addition, the composition of the material comprises from about 15 to 100% by weight by volume of the generally ellipsoidal particles having such chemical compositions, based on the total volume of the solid particles present in the composition of matter.

Advantage It is expected that the invention will provide, based on the type of the various modalities used, one or more advantages set forth in the following paragraphs. Therefore, it should be understood that the invention includes embodiments which possess less than all of the advantages described below. It is an advantage of the invention that a wide variety of feed materials can be efficiently melted in an "open" flame without special walls that configure the furnace or flame off processes to provide generally ellipsoidal particles which have only a few microns in size of average particle. Particles with an average diameter of less than 15 micrometers can be used, so that the heat transfer from the combustion gases to the particles is rapid, and the particle fusion or melting point in the burning zone of the open flame, no additional confinement by furnace walls. Although it has been described that the dispersion of fine mineral particles in the flames tends to extinguish the flames, due to the lack of sufficient heat in the flames, the method of the invention can operate without undue difficulties. In contrast to some previous methods which use temperatures in excess of 2500 ° C to produce small non-agglomerated feeds, relatively low energy conservation temperatures, for example up to about 2500, can be used successfully in the methods of the present invention. , more preferably up to about 2300 and even more preferably up to about 2000 ° C. In general, these methods will use temperatures of at least about 500, more typically of at least about 700 and, when necessary or desired, of at least about 900 ° C. The particle compositions can be used with the lowest possible melting point and, preferably, with a "fugitive" flow, for example, a bound or dissolved volatile matter such as water or sulfur oxides. It has been suggested in the prior art that combustion processes can be applied to broad categories of mineral materials including some materials that contain bound or dissolved volatile materials. However, these processes generally produce large-sized ellipsoidal particles that have a relatively large void space due to expansion and release of volatile material during heating. The present invention describes the use of feedstocks with bound or dissolved volatile materials and in a size range of up to about 25 microns to produce generally ellipsoidal product particles which have a size distribution similar to the feedstocks, in a base in weight, a portion of the product particles may have voids which in total are in the range of from about 1 to about 20 percent. Feeding compositions that have bound or dissolved volatile materials also aid the melting process. In the presence of volatile materials, compositions that could otherwise not be affected can be fused by the relatively low flame temperatures obtained through the use of stoichiometric mixtures of air and natural gas. Apparently the volatile material effectively lowers the melting point and viscosity during the melting process, and then evaporates to leave solid ellipsoids. No reports of such low temperature energy deficient means have been found to produce small diameter ellipsoids from commonly available powders. Similar small diameter spheres made only by the use of high temperature flames generated by the combustion of propane gas and oxygen have been reported. When the irregularly shaped particles are carefully dispersed and creep homogeneously into the combustion gases before ignition, an open or unconfined flame is used without "furnace walls", and rapid radiation cooling can be promoted, and can be followed, when needed, by gradual induction of cooling gases (air or water). Another advantage of the present invention is that it makes possible the production in abundance of generally ellipsoidal particles and at the same time minimizes unwanted agglomeration. In at least certain of its aspects, the methods of the present invention avoid agglutination, turbulence, collisions of molten particles, production of fused agglomerates and loss of concomitant yields. When the above methods are applied to relatively low and common melting glasses, very high yields of small diameter ellipsoidal particles are obtained as results. In fact, the yields approach 100 percent, and the product size distribution may be equivalent to that of the initial materials, indicating that there has been almost no agglutination or collision between particles in the molten state. Up to now, commercial small diameter spheres had been produced costly as a byproduct of producing larger diameter spheres. This has severely restricted its commercial availability. Surprisingly, the smaller diameter ellipsoids manufactured with the present invention are even more efficient in their production compared to the larger ones, and can be manufactured from inherently superior melt compositions. This is contrary to the prior art. When common productivity enhancers such as oxygen enrichment and pre-heating of the combustion gases are used, the small diameter products with the highest production efficiencies of known microspheres are manufactured. From 453 g (1 pound) or more of products you can get 1111 kcal (2000 B.T.U) of energy. When the above methods are applied and novel sphere forming compositions described herein are found, elliposidal particles with high single melting temperature can be formed with high efficiency. It is considered that in one or more of its aspects, the present invention represents the most cost-effective means currently known for manufacturing generally ellipsoidal particles, substantially non-hollow, of very small diameter, with a high degree of whiteness and transparency. In addition, the apparatus and the i-processing requirements to implement these methods can be significantly simpler than those previously described by other researchers. Products according to the invention can be manufactured for a wide variety of applications. For example, such products are useful as additives in thermosetting and thermoplastic resins such as silicones and fluoropolymers, in engineering plastics, in lotions and creams and in composites, paper and other materials and in any physical form, such as, for example. , molded products and single-layer or multi-layer products including especially networks and laminates. They are also useful as film anti-blocking agents and as anti-caking and anti-caking auxiliaries and as cosmetic powders with unusual "slippage" or lubricity. When they are produced in forms characterized by particular amounts of generally ellipsoidal particles, for example of about 30 or more and up to • 100% by volume based on the total volume of solids content of the compositions, the products can be used, even at relatively high concentrations, to form relatively low viscosity mixtures in liquids or molten plastics. Products that are abundant in generally helical particles can have high levels of hardness coupled with low abrasion capacity. NThe highly ellipsoidal products are also characterized by a relatively low surface area and adapt to a relatively small surface interaction with other materials which can be formulated in a variety of end-use applications. Products containing some particles having significant surface roughness can for example be used advantageously in compositions in which some degree of abrasion is desired. Fusion operations conducted according to the invention can be easily controlled to produce predetermined proportions vitreous and substantial roughness, irregular crystalline particles in the particulate product, which can thus be used to impart a predetermined degree of abrasion in the applications of end use. Such products are especially energy-saving since much higher production rates per unit of fuel consumption can be achieved where only a partial conversion to ellipsoidal particles is required.

BRIEF DESCRIPTION OF THE DRAWINGS In the appended illustrations there is shown a non-limiting mode of the invention, described in the following text, of which: Figure 1 is the general, schematic diagram of the apparatus for converting solid feed particles irregularly to a product particulate characterized by a substantial proportion of generally ellipsoidal and separated, substantially vitreous particles at least partially fused. Figure 2 is an enlarged view of the apparatus of Figure 1, which describes the mixing device to aid in the dispersion of feed particles in a stream of combustible gases. Ways of Carrying Out the Invention In general, the solid feed particles can include any material which can be fused to generally ellipsoidal products and which pass through a processing equipment, preferably without seriously damaging or frequently disabling the equipment, and without returning to the final product. Inadequate for its proposed purpose. Therefore, these particles may include one or more materials which are not fusible under the conditions maintained in the process. However, according to the invention, the solid feed particles include about 60 to 100% by weight of irregularly shaped particles of at least one feed material that can be converted, at least in part, to particles generally ellipsoidal to the heating the material while it is flowing in suspension in hot gases generated by combustion of a gas mixture in which the gas particles are suspended.

In principle, there is no reason why the full range of materials that are susceptible to fire polishing and direct fusion methods can not be used in the method. Some examples of naturally occurring and at least partially synthetic materials which may be used include: any of the known species of calcium silicates, including the wollastonites, these are fibrous structures attributable to their content of tetrahedra chains SioO4 attached of the composition (Si? 3) n, for example wollastonite ("wollastonite per se"), pseudowollastonite and parawollastonite, and hydrated calcium silicates including xonotitle (5caO.5siO2.H2O), foshagite • (4CaO.3siO2.H2O) , toberporite (4CaO.5Si02.5H20), girolite (2caO.3siO2.2H2O) flint hydrate (CaO.SiO2.H2O), chondrodite (5CaO.2siO2.H2O), afwillite (3Ca0.2Si? 2-3H2?), oquenite (CaO.2siO2.2H2O) and hilebrandite (2CaO.SiO2.H2O); nephelines, with reference to any or combination of members of the nepheline group, which include phenyline itself (Na3 (Na, K) [Al4SÍ? i6]) and calsilite (K [AlSi? 4]), in all of its crystalline structures and in solid solutions among themselves; alkali feldspars, a family of feldspars that include potassium feldspar (KAISÍ3O8) alone or in combination in varying proportions with sodium feldspar (NaAlSÍ3? ß) and which may also contain varying, but usually small amounts of calcium feldspar (CAl2SÍ2? H.H); palgysilase feldspars, a series of materials made up of calcium feldspar (CaAl2SY2? g), alone or in combination with any proportion with sodium feldspar (NaAlSÍ3? ß) which may also contain varying amounts, but usually small amounts, such as about 20% by weight or less, of potassium feldspar (KAISÍ3O8); volcanic ash of all kinds; pearls of all kinds; garnets of all types; silicate glasses of all types; silicas that occur naturally of all types; silica and silicate products of all precipitated types of sodium silicate solutions; and precipitates of solutions of silica and silcato and gels of all kinds. Feeding materials having combined or dissolved volatile materials are useful because of their property to lower the respective melting temperatures of the feedstocks. Silicas and silicates are prepared extensively by acid precipitation from sodium silicate solutions in forms with water as part of their composition, whether chemically or physically absorbed, dissolved or as water of hydration as well as with residual sulphate solutions or other metal ions as part of their composition. Other examples of feedstocks having combined or dissolved volatile materials include hydrated vitreous rhyolites, perlite, hydrated silicates include calcium silicates, sodium silicates, potassium silicates and lithium silicates; etasilicates, hydrated silicas and other silicas and silicates having combined or dissolved volatile materials such as water, sulfur oxide, sulfur dioxide, sulfur trioxide, carbon dioxide, nitrogen, other sulfur containing volatiles, and other volcanic components which they generally lower their respective melting temperatures and can contribute to the formation of voids. For examples of other suitable feedstocks containing volatile components which are incorporated herein by reference, see, Industrial Minerals and Rocks, 5th edition, Lefond, Stanley J., et al, Society of Mining Engineers of the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc., New York, 983; Handbook of Glass Properties, Bansal, Narottam P. and Doremus, R.H., Harcourt Brace Javonovich, 1986; Sol-Gel Science, The Phvsics and Chemistry of Sol-Gel Processing. Brinker, C. Jeffrey and Scherer, George. , Harcourt Brace Janovich, Boston 1990. Materials containing volatile components about 1 or at least about 2 percent by weight of such materials and up to about 7, up to about 10, or up to about 25, up to about 50 percent by weight. weight, are useful as feedstocks in the present invention.

"Perlite" is a hydrated silicate and encompasses both the hydrated volcanic glass that occurs naturally and the lightweight aggregate that is produced from the glass expansion after it has been crushed and sized. Petrologically, it is defined as a vitreous reolite that has a pearly sheen and a concentric division in the shape of an onion film. For an additional discussion of the properties and mineral exploitation of perlite, see "Perlite" by Frederick L. Kadey Jr. in Industrial Minerals and Rocks, Fifth Edition, Volume 2, page 997-1010, American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc., New York, 1983, which are incorporated herein by reference. In its naturally occurring form, perlite is a glass of reolite containing from about 2 to about 7 weight percent water, which, when heated to elevated temperatures, releases the water to expand the mineral in a hollow, relatively large particle of low specific density. Although perlite can also be presented as andesitic or dacitic glass, these forms tend to be less commercially important. Typical perlite compositions that occur naturally include 70-75% Si 2, 12-14% AI 2 O 3, 3-5% Na 2, 3-5% K 2 O, 2-7% H 2 O and less than 1% of each of Fß2? 3, TiO2, CaO and MgO.

It is known in the prior art that perlite can be dried to a lower water content prior to a combustion process to provide smaller, denser ellipsoidal particulates with greater resistance when subjected to combustion. This drying process results in higher energy costs per perlite particle unit. In the present invention, it has been found that by simply reducing the particle size of perlite feed to a size which is at or below 25 microns, preferably at about 15 microns, or more preferably at about 10 microns. Average particle size, generally ellipsoidal particulates are formed which are more resistant, much smaller and more dense. The term "hydrated silicate" means any of the silicate compositions, for example described in the reference cited above for the volatile materials in combination with 1 to 25% of dissolved or combined water. The hydrated silicates are usually crystalline minerals represented by the following formula: jMO.mSiO2.nH2O wherein j * is from 1 to 6, m is from j to 6 and n is from 1 to 6. M represents an alkali metal such as calcium, sodium, potassium or lithium and x is from 1 to 2.

A portion of the alkali feldspars and plagioclase are members of the ternary system NaAlSÍ3-KAlSiOß - CaAl2SÍ2? ß. Therefore, the terms alkali feldspar and plagioclase feldspar include the entire range of solid solutions of these three components which may exist in ore that can be mined. Among these are feldspars containing mainly sodium feldspar in solid solution with equal or nearly equal and small amounts of potassium feldspar and calcium feldspar, for example, albite and some forms of anortoclase. The content of relatively pure or concentrated forms of feedstocks used in the present invention need not correspond identically to their respective pure compositions or chemical formulas. Some factors which cause such a deviation include: slight differences between the radii of the atoms in the formulas and the proportions in which these atoms actually combine with each other when they form the mineral material; substitution, a process by which relatively small proportions of certain atoms present predominantly or originally in the crystal lattices have been replaced with, or have been supplanted by small amounts of other atoms not included in the formulas; the presence of one or more different minerals in solid solution with a particulate mineral; the presence of a small amount of materials that are provided or lost by strong heating, also called "ignition"; addition of chemical substances to feed the material in small amounts, so that the melting temperature of the feedstock is reduced and fusion is promoted or the production or modification processes of the product are favorably affected in some other way. Therefore, when in this description mention is made of feeding materials by the name or a nominal chemical formula, it is understood that such reference includes deviations that occur naturally and modifications made by man, which do not return to unsuitable materials for use in the present invention. From this, it should be apparent that when recognized nomenclature of feed materials is used in the present description, the meaning of such a nomenclature is subject to minor adjustments in meaning as described herein. In addition, chemical formulas are provided herein for convenience only and not to limit the invention. The identity and classification of the feeding materials can be determined with standard petrographic analytical techniques, for example, those described in Laboratorv Handbook of petroqraphic Techniques, by C. S.

Hutchison, John Wiley & Sons, Inc., 1974. With such techniques, the presence of phases designated by one or more of the following can be determined: X-ray diffraction patterns; determinations of chemical composition; microscopic observation; refractive index measurements, and density; calculations of the molecular norm Niggli (Catanorm); and differential solubility and differential dyeing techniques. See also American Mineraloay. "The Rosiwal Method and the Modal Determination of Rock," by E. S. Larsen and F. S. Miller, Volume 20, page 260, 1935. Many other accepted refinement techniques and processes are known to those familiar with the art. The preparation of the feedstocks may include all or any portion of the following steps, and possibly others, based on the nature of the initial material used. These can be dried, coarse crushed, magnetic separation, floating of creams, final grinding, surface treatment and classification. Some feedstocks, even when they are extracted from deposits in which they can be found at relatively high concentrations, often require some degree of refinement to produce the feedstock that substantially constitutes the ore. Among the components which can be removed by preparatory treatments are the excessive accessory minerals and minerals which impart color to the ores. Crushing can be used not only to adjust the particle size, but also to release unwanted accessory minerals and / or other ore components which may be present. In addition, the shredder can be followed by magnetic separation and / or flotation to remove the released accessory minerals and / or other constituents. Some feedstocks can be obtained in substantially "white", "colorless" or "bright" forms convertible to substantially helical, substantially white, colorless or bright particles, according to the present invention. The brightness of the feed and product particles in the form of dry and packed powder can be measured with the Hunter Lab Color Quest spectrocolorimeter system, model CQS-9400 45/0, or equivalent media at 457 nanometers. The feedstocks used in the invention, for example, may have a brightness in the Color Quest scheme of 457 nanometers of at least about 60, more preferably at least about 70, and even more preferably at least about 80. In general, the preferred mineral materials, used to produce white and / or transparent products with little color, contain very small amounts of Fß2? 3 or F? 3? 4, for example, less than about 0.1% and, of FeO, for example, less than about 1%. However, the use of colored forms of the designated materials and the production of products with color is also contemplated. Although the feedstocks used in the present invention do not necessarily contain minerals or other castable substances having an exact or nominal compositional identity, however, they may be "substantially constituted of" at least one of these substances. Therefore, the feedstocks contemplated for use in the present invention may contain about 60 to 100%, more specifically about 75 to 100% and even more specifically about 90 to 100%, by weight of one or more substances specified. These intervals generally include those materials which cause the deviations described in the foregoing of the feed substances considered from their nominal chemical formulas. Among these are: excess of one or more of the atoms that are included in such formulas; atomic substitutions, that is, atoms that are not included in such formulas and that have been replaced by included atoms; solid solutions; and other such components of, additions to or modifications of the feedstocks which do not render them unsuitable for use in the present invention, including without limitation, manmade modifications. However, the loss in the ignition materials, although usually present in natural feedstocks or at least in the raw materials from which they are prepared, are not considered as part of the feedstocks or are included in the base to apply the previous weight percentage ranges.

The expression "constituted substantially of" and the ranges provided by weight are provided to indicate that the correspondingly and respective feedstocks may contain up to about 40%; more specifically up to about 25% and even more specifically up to about 10% by weight of the "remaining" materials. The remaining materials, for example, may include accessory minerals, the above fluidizing agents and any other material or materials which may be present in the feed material without rendering it unsuitable for making products containing at least about 15%, and preferably at least about 30% of generally ellipsoidal particles fused at least partially, such as would be useful in one or more of the end-use applications described herein or in another end use. When feeding particles containing substances having a specific composition that is exact or nominal, such as a mineral, are used, it is preferred that a major portion of up to substantially all of such particles, respectively, contain about 60% to 100% by weight. weight of at least one substance of which the particles are constituted. Thus, for example, about 50 to 100%, more preferably about 75 to 100%, and even more preferably about 90 to 100% by weight of the feed particles will contain, respectively, about 60 to 100% by weight of such substance. Therefore, it is expected that feed materials may be formulated in which there are particles containing respectively an amount greater than and less than 60% by weight of the substances included, for example, as feed materials in which more than 50% by weight of the feed particles contains less than 60% by weight of the substances, but in which the weighted average composition of the feed particles reflects approximately 60 to 100% by weight of such substances. Correspondingly, feed materials can be formulated in which the particles contain respectively more or less than 40% by weight of the remaining materials, but in which the average weight composition of the feed particles reflects up to about 40% by weight. weight of the remaining materials. According to the invention, the particulate material is at least partially fused, prepared from the feed particles which can be prepared as described above or in any other suitable manner. As used herein, the term "particle" in a generic sense includes any finely subdivided form of the particular mineral involved, which, for example, may include grains, crystals, mixtures of crystals, mixed crystals, groups, agglomerates and fiber fragments. .

These materials are supplied to the process melting stage in small particle sizes. The average particle size, on a volume basis, is up to about 25, up to about 20, up to about 15 or up to about 10 microns, or 90 percent is up to about 60, up to about 40, up to about 30, in volume. To illustrate the meaning of the base in volume, as exemplified by a preferred particle size, for the feedstock and the product of the present invention, an average or average particle size average of about 5 microns means that the volume The aggregate of all particles smaller than 5 micrometers in size is equal to the aggregate volume of all particles that are larger than 5 micrometers in size. Some processes of the prior art involve grinding the feed material to the range of 0.1 to 1 micrometer. Nevertheless, this mode of preparation of the feedstock can be used in the practice of the present invention if desired, although it can be relatively difficult and expensive. For other desired end uses of the products of the invention, discrete or discrete product particles are essentially confined to a size range of 0.1 to 1 micrometers which would be too small, although they do have some amounts of particles in this range that will certainly be acceptable if not desirable in many of the end uses of the products of the present invention. Therefore, in certain preferred embodiments of the invention, the feed particles have a volume average particle size of at least about 1, at least about 2 or at least about 3 microns. Many of the feed materials contemplated, if not the majority, will have a tendency to agglomerate and form clumps consisting of multiple particles, depending on factors such as the chemistry and particle sizes of the final particles, environmental conditions such as the temperature and humidity, the manner in which the materials have been crushed, handled and stored, and the manner in which they are transported through the plant equipment, especially when the groups of particles have been subjected to compaction forces when they are resting and / or moving. The simple act of transporting particles through long duct systems, especially those with coils, elbows and other joints, may tend to concentrate the flow of particles by centrifugal or gravitational force along the periphery of the curved sections, which it takes the particles to a more intimate contact and greater addition. The adhesion can also occur in the particles at rest in volume. Adhesion can be promoted by van der Waals forces and other interatomic and molecular forces, exerted between adjacent particles. In view of the variable grouping tendencies found between different feedstocks under different conditions, the particle sizes provided herein are indicated particle sizes determined after the agglomerated groups or final particles are decomposed to the extent that this is feasible. Thus, for example, the particle size of feedstock can be determined after the sample has been agitated carefully, for example by application of vigorous ultrasonic energy, while in suspension in a liquid such as water or alcohol with use of dispersants, to separate the groups to the extent that is feasible in the context of a production control process. Subsequently, the determination of particle size is carried out by any suitable technique, such as laser diffraction and / or visual analysis of photographs by electron microscope so that, to the extent that it is feasible, the measurement of particle size is based on the sizes of the final particles in the sample. When the feedstock has little tendency, if any, for the final particles to form lumps as described above, an indicated particle size determination can be made without prior agitation in liquid.

When the particles in the feedstock have a substantial or unusual tendency to form lumps, which will be the case for many, if not most, of the feedstocks in the indicated particle size range, it will usually be it is necessary to take special precautions in order to effectively disperse the feed particles to promote particle retention in a discrete manner during the melting operation. The invention includes the dispersion of solid particles in carrier gas. As shown in the above, previous researchers in the technique of fusion to the flame have called attention to the importance of an adequate dispersion of the food particles. However, it is considered that what had previously passed as an adequate dispersion has proved to be completely unsuitable for practice in some aspects or modalities of the present invention. You can simply use two approaches for dispersion, in combination with one another and / or in combination with other different dispersion techniques. One such technique is the application of a fluidizing agent, with or without an accompanying crushing. The application of a force to the particles in lumpy forms and / or without lumps is not involved by means of a gas or a solid member to separate the lumps, in case they are present, and to evenly distribute the particles in the carrier gas, the which preferably is a mixture of fuel gas or at least one component thereof. For purposes of the invention, a fluidizing agent is any additive which, when dispersed on the surfaces of feed material particles, reduces to a significant and useful extent any tendency to form lumps that may occur. The use of certain surfactants as fluidizing agents is known to those familiar with the art by the teachings of U.S. Patent No. 4,778,502 to Garnier et al. Therefore, Garnier et al. , describe fluidizing agents as materials having good affinity for glass. When the feedstock used in the present invention is not glass, such as a crystalline mineral material, the fluidizing agent will have a good affinity for that material. The fluidizing agents described by Garnier et al. , are constituted of substances that have molecules with a polar portion constituted, for example, of hydroxyl or amino radicals. Such compounds also have a non-polar portion which promotes independence of the particles treated with the fluidizing agents. Garnier et al. , describe the use of polyalkanolamines, propylene glycol and similar compounds, which may be used in the present invention. However, in experiments with the present invention it has been found that zinc stearate and hexamethyldisilasane are more effective fluidizing agents. Triethanolamine can also be used. For further examples, see Kopatz and Pruyne in U.S. Patent No. 4,715,878, which discloses additional anionic, cationic and non-ionic treatments which may be used in the present invention. Any other surfactant or other fluidizing agent can be used. Typically, the fluidizing agents employed in the present invention are those which are effective to substantially inhibit lumping when used in amounts of up to about 1%, more preferably up to about 0.5% and even more preferably up to about 0.3% in weight, based on the weight of the feed material treated with it. However, smaller feed particles, for example those having less than 5 micrometers, will have an aggregate surface much larger than the same weight of larger particles, for example 15 micrometer particles. In this way, the finer particles and / or for those particles which tend to inevitably form clumps, larger amounts of fluidizing agent may be necessary. The fluidizing agents can be applied to the particles of feedstock and preferably to the total mass of the solid feedstocks in any effective manner, which includes the technique that has been recommended by the grinding time of the feedstock or the total mass of solid feed in contact with the fluidizing agent. It is recommended that the fluidizing agent be added to the feed material, and preferably to the total amount of the solid feed particles to be used during grinding in a ball mill, preferably as several additions during the grinding process. Such additions can be made as part of a final size reduction step in the preparation of the particles. The intimate dispersion on the particle surfaces can be obtained, for example, by particle-ball grinding for about one hour with about 0.5% by weight of surfactant, based on the total weight of the particles. However, when the particles are already in the desired particle size, the fluidizing agent can be applied only by stirring the agent and the particles together in a suitable chamber or zone. Either suitable dispersing forces can be applied in any effective manner, including, when necessary, a sufficient force to deagglomerate agglomerated particles. The following describes an appropriate example involving a gas jet and venturi system. In general, any form of force, generated by any type which is effective to separate lumps of feedstock, other solid feedstocks or both, can be used. Thus, for example, methods and apparatuses can be used which subject the clumping particles to impact with each other, or with relatively high energy gas currents and / or solid, moving or stationary objects. In this way, for example, the particles can be forcedly projected against a stationary surface such as a wall or target, or they can be passed through the blades of a fan, which include a turbine, to provide coalitions and ensure the impact between the particles and the blades of the fan. Disc mills, jet mills and hammer mills or other examples of devices can be suitably adapted to provide sufficient impact and cut the dispersion of particles, including deagglomeration. The impact includes direct frontal impacts and inclined contacts, such as those which apply shear and / or rotational forces to the lumps. In some cases, based on the properties of the particles and the manner in which they are handled and transported downstream of the dispersion operation, the use of a fluidizing agent alone or the use of a dispersing force alone may be sufficient to disperse properly the feeding material. However, when practicing certain embodiments of the invention, the amount of dispersion stress applied in some previous dispersion operations may be inadequate. Thus, when practicing the invention with solid feed particles having surprising lumping tendencies, or with downstream processing equipment that does not minimize the exertion of compaction forces on dispersed feed particles, or with high yield levels described below , unprecedented levels of dispersion efforts may be required. Therefore, it may be necessary to apply a fluidizing agent at levels hitherto considered unnecessary or even undesirable and / or to apply a force of dispersion and energy at levels beyond those considered necessary before. In order to determine whether the amount of fluidizing agent and / or force applied to the feed particles has been sufficient to deagglomerate and disperse them, the following tests can be used. The tests involve collecting a first sample of feed particles upstream of the dispersion operation and measuring by laser diffraction methods the particle size of the sample after ultrasonic agitation in water or alcohol and a dispersant. Such agitation is sufficient to allow the determination of the deagglomerated size distribution for comparison. This measurement establishes what is termed the "primary" size distribution. A second dispersed sample is collected in a diluted manner on a flat surface at any suitable point in the process downstream of the dispersion operation. For example, a glass plate having a thin film of "sticky" substance on its surface can be prepared.

The glass plate can then be quickly passed through the diverted stream from a duct receiving particles from the dispersion operation, so that the duct carries the feed particles to a burner. This sample will be measured to establish a "secondary" size distribution, for example by conventional microscopy methods, to determine the presence of agglomerates. The difference in the indicated particle size observed in the first and secondary samples is indicative of the degree to which the dispersant treatment has been effective. Relatively small differences indicate an effective dispersion treatment, while large differences indicate a less effective dispersion treatment. This difference in 90 percent is in the range of up to about 20%, and more preferably in the range of up to about 10%, on a basis in weight or volume, based on the primary distribution. That is, for feed materials with a primary distribution of 90% less than 50 microns, the dispersed sample will have 90 percent less than 60 microns or preferably less than 55 microns. An alternative procedure can be used. Samples of solid particles upstream of the dispersion stage can be collected and can always be measured dispersed in water or alcohol as in the above. A sample can be diverted downstream from the dispersion stage and can be transported by air through a laser detection device, and the dispersed size distribution as in the previous paragraph is compared. Laser diffraction techniques have the advantage that they are applied on a "real time" basis to the desired side currents from the main stream of dispersed and non-dispersed feed particles upstream and downstream of the dispersion operation. As another additional alternative, the effectiveness of the dispersion step can be determined by comparing the primary size distribution of the feed particles when dispersed in water or alcohol with a generally ellipsoidal particle size distribution fused to the flame, also when they are dispersed in water or alcohol. Correct corrections must be made for the presence of voids when they are present in the product particle. Both fluidizing agent and force are applied to disperse the particles, it may be more convenient to apply the fluidizing agent first and then continue with the application of force. However, the operation is also possible in the reverse order. However, since the ultimate goal is to disperse the feed particles in the carrier gas, it is preferred to start with application of a fluidizing agent, since this operation can then be followed immediately by application of force to the feed particles in the presence of the desired carrier gas. The carrier gas may or may not be a combustion support gas. In fact, it can be an inert gas, but in this case, the amount used must be regulated with caution. It is particularly preferred that the carrier gas is a combustion support gas, which includes one or both components necessary for combustion, which. they include the fuel and / or gas that contains oxygen. Among the appropriate combustible gases are hydrogen, methane, ethane, propane, butane and other gases which include fuel vapors - of heavier hydrocarbons and / or carbonaceous gases such as carbon monoxide. The heavier hydrocarbon fuels include those that are liquid or semi-solid at ambient conditions (20 ° C and atmospheric pressure) but that can exist substantially in the form of vapor under the conditions under which they are mixed with feed particles. Preferably, hydrocarbon fuels are those that are gases at ambient conditions that include, for example, acetylene and particularly those hydrocarbon fuels in which the mole ratio of hydrogen to carbon is about 2.5 or greater. These include, for example, butane, propane, ethane and methane, for example, in the form of natural gas.

As a gas containing oxygen, substantially pure oxygen, air enriched with oxygen or unenriched air can be used insofar as it is extracted from the atmosphere, since it is an advantage of the invention that suitable oxygen-containing gases can be used. so that they have a nitrogen content in the range from about 50 to about 80 mole percent, the rest of the balance is mainly oxygen. Preferably, the gases that support combustion are substantially free of slag sources including ash and coal particles. However, the presence of very fine particles, of clean burning, is acceptable. carbon particles and carbonaceous fuels. The preheating of the fuel, air enriched with oxygen and feed particles generally increases the productivity and decreases the contact time between the feed particles and the combustion gases necessary to at least partially fuse the particles. The preheating of the feed particles can also help to "condition" the materials by removing surface moisture or electrostatic charges and thus providing improved dispersion in the combustion gases. Either the fuel or the oxygen-containing gas can be described as "at least a portion of the fuel gas mixture". It should be understood that the above expression includes any of these components, the final combustion gas mixture that will be subsequently burned in the process and / or any other expense may be acceptably included in the gas mixture fed to the burner which generates heat in the the combustion zone. Therefore, the fuel mixture can be formed before or after the dispersion of the feed particles, and the dispersion of the feed particles in a portion of the gas mixture is considered to generically include the dispersion of the complete mixture that is to be fed to the burner or in any portion thereof, the dispersion provided can be maintained if such a proportion is subsequently mixed with the remaining components of the final combustion mixture. In certain cases, the feed particles will fire only on a portion of the fuel mixture and will be transported with that portion to the burner, where mixing of the remaining parts of the fuel mixture will take place. In other circumstances, the complete gaseous components (including vapors) of the combustion mixture will be formed upstream of the dispersion position, in which case the dispersion operation will disperse the feed particles in the complete fuel mixture. Various intermediate options are possible in which the feed particles are first dispersed with portions of any part of the fuel mixture, followed by mixing with the remaining part or parts of the fuel mixture on or before the flame front in the burner . However, in carrying out the process of the invention it is definitively preferred that the total fuel mixture is formed, and that the total amount of suspended feed particles be completely dispersed in this mixture, upstream of, and less preferably as it enters the flame front. The flame front is an imaginary "surface" or "surfaces" in which the mixture is ignited. The shape and number of the surfaces will depend on the shape and design of the burner used. The possibility is contemplated of carrying out all or at least the last stages of the dispersion and the burning of the mixture in a burner, that is, in one and the same apparatus. However, in most applications, it is anticipated that the dispersion apparatus and the flame front in the burner will be spaced apart from each other and that the feed particles suspended in this manner will be transported between these two positions. When it is necessary to transport the dispersed feed particles from a scattering position to the flame front, considerable caution should be exercised. Feed particles that have dispersed well in the dispersing operation can be re-agglomerated during transport. Transportation through long pipelines, or pipelines with a sufficient aggregate curvature in the form of elbows, coils and the like, can produce concentration of particles in a portion of the cross section of the conduit system, for example, by centrifugal forces or gravitational These forces and the concomitant concentration of particles represent forces of compaction which can agglomerate or re-aggregate the dispersed particles. Therefore, the best practice will be to restrict the total distance between the scattering position and the flame front and to maintain the flow rates of at least about 5, and preferably at least about 20 meters per second. When the suspension must pass ducts or ducts from the dispersion position to the flame front, the duct system must be designed to minimize the forces of compaction. This objective is best obtained normally by arrangements which minimize exerting centrifugal and / or gravitational forces of the kind that would tend to concentrate the flow of particles in a portion of the cross-section of the conduits. Thus, for best results, it is considered that there should be a tendency to avoid duct arrangements with radii of short curvature or sharp corners and to avoid long pipes that run horizontally. Rather, vertical pipes running relatively straight are preferred, and, in case curvatures are necessary, it is preferred to use long regular curves, especially those with radii that are equal to 5 or, more preferably 10 or more times the cross section or diameter section of the duct or duct. A particularly preferred arrangement is illustrated in the drawings and in the following text of this application. In that arrangement, the suspension is fed to a burner from the top, through very short transport tubes, which have sharp angles between any of the joining tubes, and the transport tubes and the burner are oriented vertically or at least substantially vertically (within about 20% of the vertical). The burner has a generally axial flow pattern with at least one throat oriented at least substantially vertical and a substantially horizontal outlet. Therefore, the suspension can pass essentially straight through the burner without any major change of direction and preferably with a minimum or no change in direction, except for directional changes that can be considered for lateral dispersion of the gas stream as it moves. from the supply of vertical supply to the burner outlet with movement components that are mainly axial and radial. A specific embodiment of an appropriate burner is described below and in the accompanying drawings. However, a variety of burners can be used to ignite the fuel gas mixture containing the entrained feed particles. The examples can be found in the North American Combustion Handbook. edited by Richard J. Reed. 2nd edition, North American Manufacturing Company, Cleveland, Ohio, U.S.A., 1978, the content of which is incorporated herein by reference. See also Patents of the Soviet Union Nos. 1,654,272 and 1,654,273 Nosach et al. , both assigned to As UKR Thermo-Phys. Stekloplastik Prodn. Assoc. Those familiar with the art, with the benefit of the present disclosure, will select or adapt such burners as necessary to facilitate their acceptance and transmission of combustible gas mixtures containing entrained feed particles, will adjust the sizes of the orifice ducts according to it is required to maintain such particles in a dispersed condition and will prevent the formation of lumps of the burner. Other used burner shapes can be used. Nevertheless, the preferred burners are those which do not subject the particles to compaction forces and tend to re-agglomerate them. In addition, the preferred burners are consistent with the suspension of • feed particles in the fuel mixture that is formed upstream of the flame front i and with the delivery of the particles to the flame front with the dispersion uniformly distributed through, and as they pass through the flame front in a very uniform manner, instead of being projected in a downstream area of the flame front or on the sides or center of the flame, as has been done in numerous prior art processes . The observance of these precautions is particularly important in carrying out some aspects of the invention which involve unusually high concentrations of feed particles in the fuel mixture fed to the flame front. More particularly, the concentration of the feed particles in the fuel gas mixture, for example, can be at least about 0.05 (0.05) or preferably at least 0.1 (0.1) and even more preferably at least 0.2 ( 0.2) pounds (kilogram) per pound (per kilogram) of gases in the mixture. Concentrations of up to about 1 or up to about 1.5 or up to about 2 (2) pounds (kilograms) of gases are contemplated in the mixture. Given the small particle size of the feed particles used in the invention, such concentrations are high enough to create the hope that the aggregate surface area of such small particles used in such high concentrations could eliminate the flame emanation of the burner. . Such concern is particularly great in relation to the operation at a restricted level of heat utilization, according to an aspect of the invention described later. Contrary to what is expected, it is possible to operate successfully at these high concentrations, without removing the flame and without unwanted agglomeration of particles between themselves and with the walls of the chamber, as the particles soften or partially melt and change form themselves in a chamber downstream of the burner. According to at least one aspect of the invention, the flame front and at least a substantial portion of the resulting flame are maintained in a wall-free zone which extends downstream from the front, while maintaining the particles of the flame. suspended in a dispersed condition in such an area. The nature and importance of the wall-free zone and a specific schematic example thereof is described in the following text and in the accompanying drawings. The shape of the wall-free zone and the dimensions are such that they substantially inhibit the contact of molten particles with the surfaces of the burner, the zone and the transport devices, preferably limiting such contact to negligible amounts. Several features of the present method are performed in a wall free zone. The dispersed feed particles are heated with heat transferred thereto by the burner of the fuel mixture. There is at least partial fusion of the irregularly shaped particles within at least their surfaces. The expansion of the burner gases is caused and the feed particles are caused to fuse to produce at least a partially fused bulky particulate product containing separated product particles generally ellipsoidal. Preferably, there is sufficient expansion of the burner gases and for there to be at least about 15%, or preferably at least about 30% by volume of generally produced discrete elliptical particles. Preferred embodiments produce up to about 90%, and more preferably up to about 99% of generally elliptical particles, separated. The expansion of the combustion gas stream tends to keep the particles separated from each other while in a softened or semi-melted condition, or completely melted, which reduces opportunities for coalition and particle agglomeration. The agglomeration reduces the population of separated particles and causes resulting agglomerated particles which have a larger particle size than the feed particles. Sufficient amounts of expansion and a sufficient ratio of feed particles to the released heat can be established and can be verified using the following test. The excess, if any, of indicated particle size of the product particles is determined in relation to the indicated particle size of the feed particles. This determination is based, in the case of the feed particles, on the condition of those particles before the application of the fluidizing agent and / or the dispersing force. Each of the particle size indications is based on a sample subjected to agitation, as described above, in water, alcohol or other suitable liquid. Indications of particle size can be obtained in any appropriate manner, such as by laser diffraction techniques or by analysis of scanning electron microscopy images of the samples. Preferably, the excess, if any, of the indicated 90 percent particle size of the product sample, minus the primary particle size 90 percent of the feed sample from which the product was prepared, is in the range of up to about 30%, more preferably up to about 20% and even more preferably up to about 10% of the primary particle size, on a basis by weight or, after making the appropriate corrections for any gap which may be present in the product particles, on a volume basis. The correction for the holes is made because the gaps make the product appear larger than it really is in the absence of holes and therefore wrongly suggests that there has been an agglomeration, which did not occur in reality. This correction must be made by using particle-specific gravity measurements and optical methods. According to one aspect of the invention, the total amount of heat used is in the range of 500 to about 25,000 kilocalories per kilogram (278, 13,889 B.T.U. per pound) of generally ellipsoidal particles produced. This total amount of heat includes heat used to heat, and to preheat, if any, the particles of other combustible mixture components and the fuel mixture itself. The total also includes the heat used in the expansion and heat losses, which include heat losses such as may occur due to the use of cooling gas, when applicable. The use of heat is lower for easily fused particles such as perlite, and higher for difficult melt particles such as silica. The feedstocks can be classified by Penfields "Material Fusibility Index" from 1 to 7. Using the present invention, and using this index as a discriminator for different melt strength materials, it will be found that the claimed methods can provide products with a heat consumption, in kilocalories per kilogram (BT ^ U per pound) of product, less than approximately 7000 + (3000 (Material Fusibility Index) / i) or preferably less than approximately 5000 + (3000 X (index of Material Fusibility) / 7), which is equivalent, in Kcal / Kgram to 3,889 + (1667 X (Material Fusibility Index) / 7) and preferably 2,778 + (1191 X (Material Fusibility Index) / 1 ) Note: BTU / lb x.55556 Kcal / Kilogram. The differences between the melting or softening temperatures of the different materials fed and the degree of conversion of the feed to generally ellipsoidal particles will require adequate adjustments of the feed rate and / or heat feed. An appropriate balance between the particle size fed, the melting or softening point and the feed rate on the other hand and the composition of the fuel gas and the flow rate on the other hand, will be easily established by those skilled in the art with the help of this description and without undue experimentation. It is preferred that the particles cool rapidly after the melt has progressed to the desired degree. For example, a cooling rate exceeding about 100 °, more preferably exceeding about 200 ° or even more preferably exceeding about 300 ° per second. The radiant cooling * and convection of the particles is preferably aided by the cooling air brought into contact with the fused particles with a minimum of turbulence. This minimizes the potential resulting from collisions of particles still fused or still soft with others or with surfaces of the production apparatus. The entire melting operation can be carried out in one step, with at least partial conversion of the crystalline feed particles, of irregular shape to a generally ellipsoidal shape. Thus, for example, from about 15 to 100%, more preferably from about 50 to 100% and even more preferably from about 75 to 100% by volume of the solids content of the compositions of the invention it will be in the form of generally ellipsoidal particles. For certain applications in which it is important to minimize the amount of irregularly shaped particles found in the product, the percentage of generally ellipsoidal particles may be in the range of about 90 to 100% based on the solids content of the compositions. When using solid feed particles, which have been previously fused, for example ruptured or ground glass of any kind, the present methods take advantage of the limited degree of prior fire-polishing technology. However, the preferred method for using the invention is a direct melting method, in which the fed material, or at least a substantial portion thereof, obviously did not exist as a bulky merged mass. Thus, the term direct fusion was used to refer to the methods by which the solid, irregularly shaped feed particles, composed substantially of one or more specified materials can be dispersed, heated and fused or softened sufficiently to convert them, while they remain dispersed and suspended in hot gases and under the influence of surface tension, to generally ellipsoidal particles. This method of formation produces powders in which the constituent particles can have particle-to-particle variations in the chemical composition, and in some cases in the residual crystallinity, of a type not found in the particles made by the indirect methods. Although the particles can be preheated in any suitable manner, in the melting step, heat is transferred to the feed particles through contact with the flaming combustion gases in which the particles are dispersed. More particularly, the present method involves premixing and introducing the feed particles into fluid combustible gases and heating them to the melting temperature by igniting the gases in the presence of the particles and keeping the particles in a dispersed state in the flaming gases. and possibly also by some distance downstream from the flame. During their residence in the flame, and possibly during continuous contact with the hot combustion gases outside the flame, the particles are held for a time at a temperature sufficient to soften or fuse them to the extent that the surface tension within the particles or resulting fused or partially fused droplets are sufficient to convert appreciable amounts of the feed particles to a generally ellipsoidal shape. The flow of the particles as they progress from their original non-fused state to an at least partially fused state can be in any appropriate direction or directions, including for example horizontal and / or ** vertical, with the vertical downward flow being the preferred one. When operating in the above manner, it is possible to obtain bulky, partially fused particulate products in which the average particle size, based on volume, is up to about 25, up to about 20, up to about 15, or up to about 10. micrometers, or 90 percent is up to about 60 to about 40 or up to about 30 microns, also based on volume.

Obtaining products of even smaller particle size can be very suitable. The invention makes it possible to obtain vitreous reolite products, based on silica and based on silicate with average particle sizes, based on volume, of up to about 8, or preferably, up to about 6 micrometers. Possibly depending at least in part on whether the feed particles contain sufficient volatile material to create gaps in the product, operation with a high feed concentration in the fuel gas mixture and with efficient control of heat utilization, both of which described above, there is a tendency to produce one or more useful effects on the products. These effects can cause the reduction of the specific gravity of the products, based on the density of the material fed, the creation of hollow volumes in the products, and the presence of some irregular feeding particles in the products, or a combustion of two. or more of those effects. The reduction in specific gravity may partially result from the presence of some hollow particles with voids trapped in the products or may be the result of a phenomenon related to the loss of crystallinity and conversion to a "vitreous" phase of lower density. Whatever the explanation, these reductions provide advantages in the manufacture and application of the resulting dusts. The larger volume and lower densities are generally preferred characteristics of the products, and even a small increase in volume can, over large production runs, provide equivalent volumes of salable products with considerable fuel savings. Thus, the specific gravities of the generally ellipsoidal products of the invention are preferably lower, in the range of about 1 to 15% and more preferably about 1 to about 10% less, than the specific gravities of the materials of food. Control the amount of heat energy released in the flame by adjusting or maintaining the amount of fuel, mixture of air and feed material or other materials or processing conditions in such a way that some detectable gaps in the product are maintained above and above of those that are inevitably produced, such as in amounts as low as about 1 to about 3 percent, or about 1 to about 2 percent, leads to, and can be used as an indicator of the efficient use of combustion energy. Thus, it is preferred that the processing conditions be controlled to produce in the particulate, bulky, partially fused product at least about 1% hollow volume, based on the volume of the product. However, the amount of void volume in the product can be at least about 3 or at least about 5 percent. On the other hand the hollow volume can be up to about 12 or up to about 15 percent or up to about 20 percent. For example, hollow volumes in the range of about 1 to about 15 percent or about 1 to about 10 volume percent were contemplated. The high feed concentration and the controlled heat utilization indicated above can cause some irregular feed particles to be present in the products, whether significant voids are generated or not. This mode of operation is also advantageous from the point of view of energy utilization, and may for example involve the production of products containing up to about 99%, more preferably up to about 95% and even more preferably up to about 90% by volume of discrete particles, generally ellipsoidal, fused which are substantially vitreous, with the corresponding amounts of irregular product particles present. It is preferred that, in the compositions of matter according to the invention, the carbon content of the solid particles is restricted. Unlike the carbon present in the form of organic material applied to the surfaces of the solid particles, it is preferred that the carbon content be limited to about 0.2%, more preferably to about 0.15% or even more preferably to about 0.1% by weight, based on the total weight of the solid particles. The preferred products according to the invention have little or essentially no mineral containing .1 hematite, emery, magnetite, or highly colored iron. They can, for example, contain up to about 0.2, more preferably up to about 0.1, and even more preferably up to about 0.05% by weight of Fe203 and / or Fe304. Similar limits apply to manganese, for example, MnO, and those other metals whose oxides or other compounds tend to color the products. In the case of ferrous iron oxide, FeO, which is not so strongly colored, the preferred products may contain up to about 5%, more preferably up to about 2% and even more preferably up to about 1% by weight.

When the invention is practiced with control exercise on the types and amounts of carbon in fuels and the types and amounts of carbon and other colorants in the feedstocks, solid particulate products can be produced that have levels of brilliance that make the products particularly suitable for various end uses, certain of which are described below. For example, products with brightness levels of at least about 60 and preferably at least about 80 were contemplated. The products of the invention can be characterized in that they have chemical compositions substantially corresponding to that of one or more feed materials, including mixtures thereof. The terminology "substantially corresponding to" is intended to encompass chemical compositions similar to those that could result from the at least partial melting of the feedstock material composed substantially of at least one of the materials. However, the words that correspond substantially to, have been chosen to encompass the possibilities that different production techniques may be employed and that there may be differences between the chemical compositions of the feedstocks and those of the resulting products. For example, the differences between the chemical compositions of the feedstocks and the product may result from the difference in the loss of ignition materials and the different amounts of other portions of the minerals as a result of high temperature volatilization, these other portions are usually in the range of up to about 5% by weight of the fed material. When the fed materials or other portions of the solid feed particles include crystalline matter, the at least partial melting process destroys at least a portion of their crystalline character. The mechanism by which this occurs has not been proven, but it is assumed that at least portions of the respective particles arise at temperatures above the dissolution temperature of the crystalline material. At least a portion and usually the largest portion of the crystal structure in the respective particles will be destroyed. It should be understood that the resulting particles, although having reduced crystallinity, can not in each case be described as being completely amorphous. For this reason, the particulate product is referred to herein as "substantially vitreous". This terminology makes it possible to include the possibility that the generally ellipsoidal product particles may contain some, if not all, of their original crystallinity, as long as they have been converted to form a generally ellipsoidal surface that resembles glass in terms of its smoothness, in at least surface portions of the product particles that are amorphous in nature. There are, however, no reasons, in principle, why the crystalline content of the generally ellipsoidal particles produced from the crystalline feed materials should not be reduced to a greater degree. Thus, in those particles, it was contemplated and possibly also still preferred, that most if not all the crystal structure originally present in those particles must be destroyed during the fusion operation. Of course it was also contemplated that the products according to the invention, which contain substantially vitreous, generally ellipsoidal particles, respectively, include particles of particular chemical compositions may also contain particles thereof or other compositions that are or are not substantially vitreous in nature. Such particles that are not substantially vitreous in nature, which have passed through a melting zone, may or may not have undergone melting, and in the latter case may retain most if not all of their original crystallinity and / or surface roughness. which they could originally possess. Those fusion products that contain significant amounts of both crystallinity and substantially vitreous particles can be referred to as "Christ Orphic". The crystallinity of the products produced according to the invention can be tested "roughly", which means that X-ray diffraction can be used to measure the crystallinity of samples containing fused and essentially unfused particles without measuring the amount of crystallinity present in the two different types of products. The crystallinity thus measured can be expressed in terms of a percentage by weight, based on the total weight of the sample. Based on this mode of measurement, products containing up to about 90%, more preferably about 0.1 to about 75%, and even more preferably about 5% to about 60% crystallinity were contemplated. In some circumstances, near complete conversion to generally ellipsoidal products can occur in combination with surprisingly high residual levels, for example, 20%, of crystallinity. Incomprehensibly, products produced from non-crystalline feed materials remain essentially amorphous or vitreous. A preferred form of the apparatus that has been employed to produce the products of the present invention using the method of the present invention, and which has also been used to conduct the examples set forth below, will now be described with the help of the drawings. It should be understood however that such described apparatus is illustrative only, and that the invention is not intended to be limited by or to the particular apparatus described. The illustrative equipment shown in Figures 1 and 2 includes separate sources 1 and 2 for the oxygen-containing gas and fuel, which may or may not include facilities for preheating the gas and / or oxygen-containing fuel. Thus, for example, the oxygen-containing, filtered gas is conducted from its source 1 through a suitable compressor or fan (not shown), valveing (not shown) and flow measurement equipment (not shown) toward a gas tube containing oxygen 3 to provide an adjustable, stable flow of such oxygen-containing gas. The fuel gas, after passing from its source 2 through the independent valving (not shown), flow measurement device (not shown) and release tube 4 is removably adjustable by suction and at a flow rate stable to tube 3 at junction 5. There, if necessary or desired, a flow control orifice is provided to properly match the volume of the fuel to the usually larger volume of oxygen-containing gas. For example, where the oxygen-containing gas is air and the fuel is natural gas, a volume ratio of approximately 10: 1 may be employed. The premixing of the gas mixture that supports the resulting combustion with the feed material before ignition of the fuel can be done in Y 6, a mixing connection in the form of "Y" generally having the upper part that intersects the input legs of gas and feeds 7 and 8 which are joined and fed together to the lower outlet leg 9. The gas inlet leg 7 is a vertically oriented extension of the gas tube containing oxygen 3. The feed inlet leg 8 f also extends upwards but is inclined from the vertical, intersecting at an acute angle, for example about 10-45 °, with the gas inlet leg 7. A uniform flow rate of feed into the inlet leg of feed 8 is effected by feeding the feed under moderate humidity and temperature, for example at room temperature, from a vibrating discharge funnel 13 on a vibrator conveyor io 14 and from that conveyor to the input of the power input leg. Weight-loss screw feeders with mechanically agitated hoppers and vibration-assisted discharge are useful for feeding very fine powders. The supply pipe 16 provides a supply of dispersion gas such as air which can thus represent a small portion of the gas that supports the combustion to be burned. As shown in greater detail in Figure 2, which is an elongated, partially transverse section of Figure 1, the dispersion gas discharged from the supply pipe 16 passes through a jet nozzle 17 towards the inlet leg. of feed 8 to suck the feed from the inlet 15 to the leg 8 and through the venturi 1 to aid in the dispersion of the feed particles. The feed particles, predispersed in the dispersion gas, are released through a bevelled end 19 of the feed inlet leg 8 to the intersection of the Y 6, where they are mixed and further dispersed in the combustion gases that they pass down mechanically through the gas inlet 7. The dispersion of the feed in the combustion gases can be achieved and improved by selecting the ratio of gas to feed mixed in the Y and the volumetric flow velocity of the gas per unit cross section of the gas pipe connected by that provided from the gas inlet leg 7 to the outlet leg 9 of the Y 6. In experiments conducted in the apparatuses described herein, ratios in the range of about # 0.4086 kilograms (0.9) to approximately 4.086 kilograms (9 pounds) of feed per 28.3 m3 (1000 ft3) (cubic foot at 15 ° C) of the fuel mixture e-air used. The fuel gas used was for example 11.32 mVhour (400 ftVh) through a gas pipe having an area of approximately one square inch. Those skilled in the art will appreciate that the ranges of ratios and speeds that will work in other types of equipment, and the intervals that will work taking the best advantage of such equipment., they can vary from the given values and can be found through tests, which such people can easily lead with the help of this description and without undue experimentation. It is particularly important to maximize the amount of combustion-bearing gases injected to the particles fed by high-energy jets to accelerate the feed particles and break up the agglomerates by cutting and impact. For the proper dispersion of fine powders at high speeds, the particles and combustion air can be dispersed by passing them through a hammer mill, disk mill or other de-agglomeration device, which functions as the sole means of dispersion or as a upstream pretreatment for the feed particles which will also be dispersed with the aid of the fluidizing agent and / or the described air jet. In the present preferred embodiment, as can be seen in Figure 1, the burner 20 is a "straight fit" gas burner that discharges downward and has a nozzle that retains the flame of a diameter of 1.75 inches 22 adapted in a manner that the internal pilot is powered by a current free of feed particles. Such a burner is described on page 431 of Reed's book mentioned above. In the present embodiment, this burner has in its upper part a common inlet 21 for the mixture of particles and gas that supports combustion, received from the outlet leg 9 of the Y 6. The nozzle 22 of the burner 20 penetrates the wall horizontal upper 26 of the combustion chamber 27. An annular opening in the wall '26 surrounding the outer peripheral surface of the nozzle 22 represents an inlet port 28 for the cooling air. A short distance below this door, at the bottom of the nozzle 22, is a generally horizontal burner mouth 29 for the discharge of the fuel gas and the feed introduced into the combustion chamber 27. Combustion occurs when the particle-gas mixture fuel leaves the mouth of the burner 29 and continues downward into the combustion chamber 27. Although it is possible to vary widely the internal cross sections of the gas channel mentioned above in the Y and the burner, a certain balance between these dimensions must be maintained. . The objective to be satisfied in the selection of these dimensions is to keep the feed particles dispersed in the resulting flame, while maintaining a sufficient flow velocity through the mouth of the burner 29, given the available volumetric velocity of the gas and feed , to effectively discourage or prevent the "backfire", re-treat the flame inside the burner 20. As those skilled in the art will appreciate, a variety of other burner designs are available which can achieve those objectives. It is believed that it is beneficial to generate the flame of the burner in a "wall-free" environment. This means that the side walls 32 of the combustion chamber 2 are placed at a predetermined distance laterally or transversely of the flame path that emanates from the burner mouth 29. There should be sufficient distance laterally or transversely from the perimeter of the flame towards the walls 32 to give the flame a substantial amount of freedom to expand in the lateral or transverse direction. Alternatively, this distance should be sufficient to substantially inhibit or prevent melting or softening of the still un-solidified particles that have been at least partially fused in the flame upon contact with the side walls 32 and adhered thereto. Preferably, the distance should be sufficient both to allow freedom for expansion and to inhibit the adhesion of the particles, as described above. In the present burner mode, the mouth of the burner 29 is located on the extended shaft 33 of the burner and projects a flame along that axis, generally in the direction in which the axis extends. Thus, in this case, the side walls 32 are positioned at a predetermined lateral or transverse distance from that axis, to provide the freedom and / or inhibition described above. The side walls 32 may be of any suitable configuration, but are cylindrical in the present embodiment, as seen in a plane perpendicular to the axis 33, and have a diameter of approximately 0.9144 m (3 feet). The prior art suggests introducing cooling gas to the combustion area, perpendicular to the path of the flame and presumably a short distance downstream of the burner. According to these teachings, the flame disappears where it comes in contact with the cooling gas, and the technique could thus be used to control the amount of time during which the feed particles are held at the melting temperature. That system can optionally be used with the present invention. However, the present invention also provides and preferably employs a different and advantageous cooling technique, as described below. In connection with the present invention it has been found that assistance should be obtained in the insulation of molten or softened particles from the side walls of the combustion chamber 32, and in some cases from the upper part 26, of a cooling gas stream. , such as the air introduced through the aforementioned door 28. This current may, for example, and preferably be forced to flow smoothly in a co-current flow along the flame side between the flame and a flame. or more of such walls. The term "soft", as used herein, means that the direction and / or flow velocity of the cooling gas is co-current with the flame and allows lateral expansion of the combustion gases. This cocurrent flow occurs at least along an appreciable portion of the length of the zone in which the flame is present in the hot combustion gases, and possibly also during an appreciable distance downstream from that zone. It is recommended that the direction of the cooling gas be established or controlled in such a way that the hot combustion gases can continue to expand laterally and the cooling gas can flow downstream cocurrent for an appreciable distance with such gases, during which the gases of combustion can continue to expand laterally. In view of this objective it is recommended to control or sufficiently limit the linear flow rate of the cooling gas to substantially inhibit or substantially prevent the flow of cooling gas from generating a turbulent flow in the central axis, or in the core, of the gases adjacent hot combustion It should be understood, however, that the mere presence of cooling gas adjacent to the hot combustion gases, especially when this is substantially colder and / or moves substantially slower than the combustion gases, will encourage the formation of some turbulent streams. in the outer or peripheral portion of the combustion gases. In this way, the goal of the above limits imposed on the cooling gas is the substantial inhibition or substantial prevention of any tendency for the cooling gas to lead to an immediate total breakdown of the flame, and preferably also of the flow of cooling. combustion gases that continue downstream of the area in which the flame is present. In the present embodiment, in which the air inlet door 28 surrounding the burner nozzle 22 in the upper wall of the combustion chamber 26 is substantially annular, the cooling air is admitted into the chamber in the form of a curtain mobile, induced by airflow by the burner and downstream collection equipment, which substantially surrounds the entire flame while dispersing the particles, inhibiting the agglomeration and other functions of the cooling gas described above. Optionally, additional air, water or other suitable dilution gas can be admitted to the combustion chamber downstream of the burner. In any case, sufficient cooling is preferably introduced to bring the hot gases to less than about 800 to about 1200 ° C before entering the pipelines for transport to the collection devices. Any suitable means and measurements can be used to collect the at least partially fused particulate product. Those skilled in the art are well aware of the proper systems. In the present embodiment the combustion chamber has an integral hopper section 36 with a conical bottom section or similar to a straight funnel 37 in which the product falls by gravity and / or is extracted by the air stream provided by the equipment of downstream collection. An inlet 38 in the lower part of the hopper 36 is connected through the conduit 39 to the collection equipment, such as a gas-solids separator 40, which may be of the cyclonic type having upper and lower outlets 41 and 42 for gases and particulate products respectively. The outlet 41 can be connected to a bag filter (not shown), if desired, and to a fan (not shown) to provide an air stream through the collection equipment. In the melting of the feed particles by the method described above, sufficient heat is transmitted in the particles, while dispersing, to produce a sufficient softening or melting in the respective particles, so that the surface tension is capable of converting a portion appreciable of them of their original irregular shape a substantially more regular shape, while providing them smooth surfaces. The particles are then kept out of contact with each other and with other surfaces until they have been cooled to a non-stick state. If it were possible for each individual particle to undergo fusion and experience the effects of surface tension without interference by air currents, by other particles or by the components of the fusion apparatus, without lack of homogeneity in the particulate composition, with sufficient time at a suitable viscosity, and with uniformly rapid cooling, the particles of the resulting product could be perfectly spherical. However, in practice, a certain amount of interference, inhomogeneity and variations in residence time and viscosity will occur. In this way, to some degree, there will be product particles that are less than perfectly spherical. Some of those less than perfectly spherical particles can be very irregular in shape, and in some cases a substantial percentage of irregular particles will be intentionally retained in the resulting products. Yet, the objects of the invention are achieved when a substantial portion of the irregular feed particles are converted to a shape that appears at least generally ellipsoidal when viewed under amplifications as described below and when the resulting product, as originally produced , or as packaged, or combined with other materials for any suitable end use, contains from about 15 to about 99%, or from about 50 to about 99%, or from about 75 to about 99% or from about 90 to about 99 % by volume of the generally ellipsoidal particles. According to a particularly preferred embodiment of the invention, the products contain substantially spherical particles in amounts within at least one of those ranges of percentages by volume. More particularly, for those end uses in which the discretion of the particles is considered important, it is preferred that, in the compositions of matter according to the invention, the above-identified portion of the resulting product representing approximately 15 to 100% by volume of particles generally ellipsoidal should itself contain from about 50 to about 99%, more preferably from about 70 to about 99%, and even more preferably from about 90 to about 99% by volume of substantially discrete particles. "Generally ellipsoidal" particles are those whose two-dimensional amplified images appear generally rounded and free of sharp corners or edges, or do not appear to have a true or substantially circular, elliptical, globular or any other rounded shape. Thus, in addition to the truly circular and elliptical shapes, other forms with curved but not circular or elliptical edges are included. The "substantially spherical" particles are those whose amplified two-dimensional images appear at least substantially circular. A particle will be considered substantially spherical if its edge fits within the intervening space between two concentric, truly circular edges that differ in diameter from one another to approximately 10% of the diameter of the largest of those edges. In general, a given particle will be considered "substantially discrete" if the edge of its image does not touch or overlap that of any other visible particles in an amplified view of the given particle and such other particles. However, a given particle will still be considered substantially discrete if its image touches or overlaps the edge of one or any number of other particles, if the largest visible dimensions of all those other particles are respectively in the range of up to about 10. % of the largest visible dimension of the given particle. The shape, discretion and particle size of the feed material and product particles can generally be judged by viewing their two-dimensional photographic images at an amplification of X1000. Such images can be provided by an optical or scanning electron microscope or by an alternative amplifying device suitable for the same amplification or equivalent. Only fully visible particles within the image under review are considered in the application of the above definitions and the determination of the amounts of particles present. The samples used for such analyzes should be prepared in such a way that the particles are sufficiently dispersed in the amplified views to minimize the particle-to-particle superposition of the discrete particles. The number of particles counted to determine the volume percentage of the particles of a particular type in a sample should be sufficient to provide an acceptable level of confidence, such as about 95%. The generally ellipsoidal, substantially spherical and substantially discrete definitions given above are applied based on the images described above observed to the indicated amplification, even if the particles in question may not conform to those definitions if they are viewed at higher amplification levels. Thus, for example, particles whose edge appears to be rounded and whose surfaces appear to be mostly or substantially completely smooth at this level of amplification will generally be considered ellipsoidal even if they might appear less rounded and / or less smooth to levels of higher amplification. Determinations of particle size, discretion and volume percent for particles of different sizes and shapes, whether generally ellipsoidal, substantially spherical or irregular, may be based on the procedures described in Handbook of Mineral Dressing, by A.F. Taggart, John Wiley & Sons, Inc., New York, 1945, chapter 19, pages 118-120. Many refinements of this basic method are known to those skilled in the art. For example, two-dimensional amplified images of adequately prepared samples can be analyzed using a Leica Q570 image analysis system in conjunction with a Leitz Ortholux microscope or a source that feeds scanned SEM (scanning electron microscopy) data. Such automated image analysis systems can make direct measurements of the area, perimeter and aspect ratio of the particle to determine equivalent circular diameter values for two-dimensional images of all observed particles, regardless of shape. Those correspond substantially > to the actual heats for all the observed particles. Such systems readily determine the equivalent circular diameter values for particles in the selected particle size categories. When provided by the operator with a properly defined "discrimination factor", such systems can distinguish particles that are substantially ellipsoidal or substantially spherical from those that are not and can determine the values of the area that correspond substantially to the areas added particles inside and outside those categories. A discrimination factor that has been used with apparently acceptable results to distinguish generally ellipsoidal particles from those that are not, and that may or may not be subjected to further refinement, is as follows: CSF - * • AR >; 0.55, where CSF = circular shape factor (4p X particle area -s- particle perimeter2) derived by the system and AR = aspect ratio (dimension or largest diameter of the particle -s- dimension or diameter more small particle) derived by the system. The image areas of the respective aggregates for particles whose images are and do not fall within the generally ellipsoidal or substantially spherical category can then be converted into percentages by volume by formulas familiar to those skilled in the art. Automated image analysis systems of the above type are available with display devices or screens in which an operator can see the particles under analysis. Such a display device or screen allows the operator to visually determine between the particles that are and not in a selected category, for example generally ellipsoidal, substantially spherical or substantially discrete as defined above. The particles thus defined can be selected to be included in groups of particles whose aggregated areas can then be determined automatically, followed by the conversion of those areas to percentages by volume as described above. The following examples, conducted in the apparatus described in Figures 1 and 2, are offered by way of illustration, are not intended to limit the scope of the invention.

Example 1 800 grams of Kansas volcanic ash (72.8% of SiO2, 14.6% of A1203, 5.8% of K20, 3.9% of Na20, 0.75% of Fe203, 0.28% of CaO, 2% of H2O) were placed in a vibratory mill with 20 grams of hexamethyldisilazane and 1500 grams of 1/4"alumina spheres. After tumbling for 10 hours the ash is recovered as a free-flowing powder with 90 percent of somewhat laminated, irregularly shaped particles that have a diameter of less than 10 micrometers and a density of 2.5 g / cc.

In the apparatus of Figs. 1 and 2, air was introduced to the gas tube containing oxygen 3 at about 7,642 m 3 / hour (270 ftV / h) (cubic foot per hour at 20 ° C). Natural gas with a heating value of 0.5556 Kcal / kg (1,000 B.T.U./pie.sup.3) was introduced separately and aspirated into tube 3 from the fuel delivery tube 4 at junction 5 to approximately 0.9905 mVhoz (35 ft.V.). An additional 2,264 mVhora (80 ftVhora) was injected from the supply pipe 16 and the nozzle 17 through the venturi 18 into the feed inlet 8 of the Y 6. During a period of about 6.6 minutes, one hundred grams of the ashes , aspirated and introduced with a stoichiometric mixture of air and natural gas as described above, were supplied to a downward directed flame of approximately 19,444.6 kcal / kg (35,000 btu) per hour in the apparatus of Figures 1 and 2. The mixture of hot gases and the introduced ellipsoidal particles was cooled by mixing with air at room temperature. Using a cyclone, the solid particles separated from the gases. The pulverized product has a density of 2.1 g / cc and an average particle size of 4.5 microns. More than 90 percent of the ellipsoid particles in the ashes contained voids, visible in microscopic observations, and these "bubbles" contribute to the reduction in average particle density compared to the starting volcanic ash. , Example 2 Synthetic precipitated sili products: "FK320"; "FK16"; "SIPERNAT 22;" SIPERNAT D17"and" EXTRUSIL "and a synthetic aluminum sili," SIPERNAT 44", were obtained from Degussa Coporation, each of these powders, containing from 3 to 22 percent water, dispersed in a stoichiometric flame of air and natural gas in the manner described above to produce powders with an abundance of spherical particles with average particle diameters of a few micrometers.One more the voids are evident in the occasional spherical particle.

Industrial Applicability It is expected that the products according to the invention will be supplied to the industry as compositions of matter that are substantially composed of solid particles, including generally ellipsoidal particles with or without particles of other forms. However, due to the various practical uses of the particulate products, it is expected that the subject compositions of the present invention, to which reference is made in the appended claims, will take many different and varied forms. Below are some illustrations. The compositions of matter containing the solid particles described herein can take the form of mixtures such as solid particles, including generally ellipsoidal particles, with polymeric materials of all types, for example thermoplastic and thermosetting resins, elastomers and other forms, including In such mixtures, the volume of solid particles, based on the total volume of such particles and polymeric material, may vary within the range of about 0.05% (for example, when small amounts of particles in films as antiblocking agents) up to about 99.9% (for example, when small amounts of polymer are present as a surface treatment on the particles) Katz and Milewski, supra, on pages 311 to 315, discuss the uses of glass beads in polymeric material. The products of the invention will be useful in many of those applications, especially since the invention provides an economical source of generally ellipsoidal particles in the range of up to about 15 micrometers in average diameter. Similarly, with only minor adjustments in the formulation, generally ellipsoidal particles will be useful for most if not all of the applications described in the literature for molten silicas, spherical alumina, silica, feldspar, calcium carbonate, nepheline syenite. , alumina trihydrate and other particles used as additives or pure powders. The products of this invention can replace at least partially and in many cases completely the volume of particulate additives used or contained in a given application or formulation. Only minor additional adjustments will be required to achieve the desired viscosity, texture or other desired properties. Particles with a size range with an average diameter of about 15 microns or less are important for producing compositions, including cast products and sheets, with smooth surfaces having high abrasion resistance and staining or staining. Accordingly, these particles will be especially useful in plastics to polymers, polyesters, phenolic, epoxy and other resins used to prepare a wide variety of molded compounds and molten members for the electric transportation industry and other industries, as well as to prepare mixtures of lamination, sheets and other products for counterfaces, toilets and other applications for the construction industries and contractors. For those purposes, the solid particles of the present invention, in their different mixtures with polymeric material, are preferably present in amounts of about 5 to about 65% by volume, based on the volume of the total composition. Another valuable end use is in polymeric films of any type that contain such solid particles. For example, when incorporated into polymer films in a sufficient amount, the particulate products impart anti-blocking properties to such films. To illustrate, by homogeneously mixing about 0.05 to about 0.5% by volume of those products in polyethylene and / or other films, those films are allowed to be stored in stratified form (including rolls) under typical storage conditions, for example, at film temperatures. up to approximately 45 ° C, without "blocking" or melting the film layers together. In the preferred products for those anti-blocking applications, 90 to 100% by volume of the particles having diameters of up to about 25 microns and about 80 to 100% by volume of the particles are generally ellipsoidal. Paint additives represent other valuable applications. The economic availability of products with low color in small sizes that are abundant in rounded particles makes it possible to add those products to liquid coating compositions as fillers or fillers in the range of about 5 to about 50% of the total volumes of such compositions. With particulate products having very small particle sizes and an abundance of substantially spherical particles, the viscosity increases only relatively modestly, for example, less than half the increase in viscosity that would be expected when using fillers in form of typical irregular shaped particles. Preferred examples of particulate products useful for such applications are those having a brightness of 457 nanometers Color Quest of at least about 60, more preferably at least 70, and most preferably at least 80, with about 90 at 100% by volume of the particles with a diameter in the range of up to about 25 microns and with about 75 to 100% by volume of the particles being generally ellipsoidal or substantially spherical. Also, the compositions of the present invention include liquid coating compositions that are curable to decorative coatings or solid coatings, including architectural paints, industrial coatings, wood stains or other coatings. In those compositions, the particulate materials may be used if desired to displace other ingredients that are expensive or environmentally problematic, such as solvents. Also, products composed largely of rounded particles, for example those containing about 70 to about 100% by volume of generally ellipsoidal particles, can be incorporated to provide better durability. The products of the invention can also be used in coatings in sufficient amounts to impart controlled surface texture to those and thus provide gloss reduction and "release" effects in combination with improved stain and stain and scour or abrasion resistance. Products in which approximately 90 to 100% by volume of the particles have diameters of up to about 25 microns and which contain about 60 to 100% of generally ellipsoidal particles are preferred for those applications. The solid particles of the present invention, which should be easily made with melting points higher than those of the glass beads, are potentially useful in formed or machined metal members of the type including a matrix of metallic material in which the particles Solid materials are dispersed, for example as an additive to improve durability or hardness. Such metal materials for example can be selected from zinc, aluminum and alloys containing at least such metallic materials. In such compositions, the products of the invention offer potential savings in both weight and cost. Fillers generally ellipsoidal, inert, non-abrasive, are generally useful in soap and cosmetic formulations, due to the smooth texture imparted by such formulations. Thus, it is possible to provide compositions in the form of smooth textured fluid or dispersible material comprising the solid particles of the present invention dispersed in a pharmacologically acceptable carrier to be applied to the skin or other parts of the human or animal body. Particulate products free of heavy metals and other harmful materials will be required in many if not all of these applications. In the preferred products for those applications, approximately 90 to 100% by volume of the solid particles will have diameters in the range of up to 10 microns and approximately 90 to 100% by volume of those particles will generally be ellipsoidal or substantially spherical.

The paper industry has large requirements for special fillers of all types, and the invention offers the opportunity to form papers with a high degree of uniformity and surface durability. Thus, the invention makes possible material compositions in the form of a smooth surface fabric, comprising woven or non-woven fibers as the main structural elements of the fabrics, with the solid particles of the invention being present in such fabrics as an additive, since whether or not the fabrics include polymeric material. For those applications, products with average particle sizes in the range of about 10 microns are preferred. The particles according to the invention are useful for preparing many waterproofing agents, organic and inorganic cements, and other compositions. Among these are compositions of matter in the form of smooth textured fluid or dispersible adhesives comprising the solid particles dispersed therein. It was anticipated that the products of this invention that are abundant in rounded particles, preferably those containing from about 50 to 100% by volume of generally ellipsoidal, or substantially spherical particles and having an average particle size in the range of up to about 10 micrometers, will be useful to modify the properties of adhesives, provide combinations of adhesion, elasticity, elongation and possibly other properties that were not previously available. Other useful compositions include powders that contain at least one component that forms an inorganic cement in admixture with such solid particles. The white grades of the products of the invention are useful in those compositions wherein appearance is an important feature. For example, transparent products having a brightness at 457 nanometers Color Quest of at least about 80 and average particle diameters in the range of up to about 10 microns are preferred for use in dental compositions. Katz and Milewski, supra, in chapter 4, describe the use of mixtures of particles with large and small diameters to provide combinations with high "packing" factors or high bulk density. Such combinations are important for the formulation of compositions in which the generally ellipsoidal particles represent a very high volume percentage of the solid particles in them, and consequently contain a minimum amount of other ingredients. Compositions that give better performance at elevated temperatures, such as those that can be used in airspace and other applications, are possibly made by such formulation techniques. The invention makes readily available products that are abundant in particles within the small size ranges necessary for those mixtures. The generally ellipsoidal particles of this invention, either alone or in combination with other materials, including for example other types of solid or cellular particles, can be used to form non-fluid porous structures. The particles of such structures can become temporarily or permanently adherent to each other by sintering at high temperature or joining the particles together in a single volume, such as in small additions of adhesives or cements. These products are useful in block shapes, plates or other forms to act as lightweight structural materials. By proper selection of the particle size and the level of binding agents, the porosity of those materials can be controlled to provide useful filters, such as for gases and / or liquids. The particles according to the invention are useful in curable liquid and solid polymer compositions, generally. At least some of them are however, particularly useful in UV curable compositions because of their relatively high UV transparency, compared to other fillers. The pure or pulverized forms of the products of this invention, due to the rounded particle shapes, have an unusual degree of lubricity or contact slippage. This property makes those embodiments of the invention that are abundant in generally ellipsoidal particles preferably useful in a wide range of applications, such as lubricants in a variety of friction control applications, powders for dermal protection, slip agents. between layers and film and paper agents to control the thickness or adhesion of surfaces in general. Any form of surface treatment with silane coupling agents, organic titanates, surfactants, dispersants, wetting agents, attack active (acid or basic) or other agents, and any other method of surface modification, can be used to improve the performance of the generally ellipsoidal particles in any application. See Silane Coupling Agents. Pluedde ann, EP, 2d ed., Plenum Press, 1991. For additional information regarding organic titanate and silane coupling agents, to improve bonding with polymeric materials, see also USPatents 3,834,924 to Grillo, 3,290,165 and 3,567,680 of Iannicelli, and 4,268,320 and 4,294,750 of Klingaman and Ehrenreich. The end uses of the products of the present invention described above are those which until now appear to be the most attractive. The above descriptions of the embodiments of the invention and the end uses thereof have been given basically for purposes of illustration and to delimit the invention. Thus, it should be considered that the invention includes all modalities falling within the scope of the following claims and equivalents thereof. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (22)

1. CLAIMS 1. A method for the production, in bulk, of materiaJ. particulate, including generally ellipsoidal solid product particles, the method is characterized in that it comprises: A. dispersing in gaseous suspension, in at least a portion of a fuel gas mixture, solid feed particles including approximately 60 to 100% in irregularly shaped particle weight of at least one fed material that 1. has a volume average particle size of up to about 25 microns, and 2. is at least partially convertible to generally ellipsoidal particles by heating the material, while it is flowing in suspension in the hot gases generated by the combustion of such gaseous mixture; B. releasing the fuel mixture and feed particles suspended in the front of a flame in which the mixture is incinerated, the concentration of the feed particles in the mixture is in the range of from about 0.2 to about 2 Kilograms per kilogram of mixture; C. maintaining the front of the flame and at least a substantial portion of the resulting flame in a wall-free zone, which extends downstream of the front; D. at the same time maintaining the suspended particles in a dispersed condition, heating the particles with the heat transferred to them by burning the combustible mixture, thereby causing at least partial melting of the irregularly shaped particles within at least their surfaces; E. expanding the burnt gases and causing the particles to melt in an amount sufficient to produce at least a partially fused bulky particulate product, wherein about 15 to 100% by volume of the bulked particulate product is discrete, product particles. , generally ellipsoidal; and F. restricting the total amount of heat used 1. for heating, including preheating, if any, of the feed particles, any other components of the fuel mixture and the fuel mixture itself, 2. for the melting of the particles, 3. for the expansion, and 4. for the heat losses, 1U / to an amount in the range of from about 278 to about 13,889 kilocalories per kilogram of product particles, generally ellipsoidal produced.
2. 2. A method for the production, in bulk, of particulate material, including generally ellipsoidal, solid product particles, the method is characterized in that it comprises: A. providing solid feed particles including about 60 to 100% by weight of irregularly shaped particles of at least one fed material having a volume average particle size of up to about 25 microns; B. applying to the feed particles a fluidizing agent and / or force for the dispersion of the feed particles in gaseous suspension in at least a portion of a fuel gas mixture; C. Release at the same time mix fuel and feed particles suspended to the front of a flame in which the mixture is incinerated, inhibit the agglomeration and / or reaglomeration of the suspended feed particles and distribute the particles present in the suspension to through the front of the flame; D. maintaining the front of the flame and at least a substantial portion of the resulting flame in a free zone 1U0 of walls, which extends downstream of the front; E. while maintaining the suspended feed particles in a dispersed condition, heating the dispersed feed particles with heat transferred to them by igniting the fuel mixture, thereby causing at least the partial melting of the particulates irregular within at least their surfaces; F. apply sufficient fluidizing agent and / or force in the dispersion operation of paragraph B above, sufficiently inhibit the agglomeration and / or reaglomeration during the steps of paragraph C above, sufficiently expand the ignition gases in the wall-free zone of paragraph D above and establish a sufficient weight ratio of the feed particles per unit of heat released in that zone to produce at least one voluminous, partially fused particulate product. 1. wherein approximately 15 to 100% by volume of the voluminous particulate product fused is of discrete, generally ellipsoidal product particles, and 2. where the excess, if any, of the indicated 90% particle size of a sample of the product that has been vigorously stirred in liquid, minus the primary particle size of 90 percent of a sample of the fed, from which the product has been prepared and which has been vigorously stirred in liquid, is in the range of up to about 30% of the primary particle size, on a weight basis or, after making appropriate corrections for any voids that may be present in the product particles, or a base in volume.
3. 3. A method for the production, in bulk, of particulate material, including generally ellipsoidal, solid product particles, the method is characterized in that it comprises: A. dispersing in gaseous suspension, in at least a portion of a combustible gas mixture, particles of solid feeds including about 60 to 100% by weight of irregularly shaped particles of at least one feedstock that 1. has a volume average particle size of up to about 25 microns, 2. has a tendency to agglomerate and form lumps when groups of the particles are subjected to compaction forces when they are at rest and / or in motion, and 3. it is convertible at least in part to generally ellipsoidal particles feeding the material, while 11U it flows in suspension in the hot gases generated by the combustion of the gaseous mixture; B. applying to the feed particles a quantity of fluidizing agent and / or an amount of force sufficient to disperse the feed particles in the gas mixture or a portion thereof, so that the difference in particle size of 90 indicated percent of the primary and secondary samples of the feed particles that have been taken respectively before and after the dispersion, the sample of primary particle size has been vigorously stirred into liquid before measuring its particle size, is in the range of up to about 20% of the primary fed particle size, based on a volume; C. after dispersing the feed particles in the gas mixture or a portion thereof, and while releasing the fuel mixture and feed particles suspended to the front of a flame, in which the mixture is incinerated, inhibit the agglomeration and / or reagglomeration of the suspended feed particles and distribute the particles present in the suspension substantially uniformly through the front of the flame, the concentration of the feed particles in the mixture is in the range of about 0.05 to approximately 2 pounds per pound of mixture; D. maintaining the front of the flame and at least a substantial portion of the resulting flame in a wall free zone, which extends downstream from the front, while maintaining the suspended feed particles in a dispersed condition; E. heating the dispersed feed particles with heat transferred to them by igniting, and while the particles enter, the fuel mixture at a melting temperature in the range of about 500 to about 2500 degrees centigrade; F. expanding the combustion gases and causing the fusion of the feed particles introduced in sufficient quantities to produce a bulky, at least partially fused particulate product, wherein approximately 15 to 100% by volume of the bulked particulate product is product particles, discrete, generally ellipsoidal; and, G. to restrict the total amount of heat used 1. for heating, including preheating, if any, of the feed particles, any other components of the fuel mixture and the fuel mixture itself, 2. for the fusion of the particles, 3. for expansion, and 4. for heat losses, to an amount in the range of about 278 to about 13,889 kilocalories per kilogram of product particles, generally ellipsoidal, produced.
4. 4. A method for the production, in bulk, of particulate material, including generally ellipsoidal, solid particles, the method is characterized in that it comprises: A. putting in a dispersed condition, irregularly shaped feed particles which 1. are substantially composed of a or more silicas and / or silicates that are found naturally2. are at least partially convertible to generally ellipsoidal particles by heating the material while it is flowing in suspension in the hot gases generated by the combustion of the gas mixture, 3. they have a volume average particle size in the range up to about 15 microns, and 4. include enough volatile material in the form of combined or dissolved water to generate void in at least a portion of the fused product particles, and B. to maintain the feed particles in a dispersed condition at the same time, to heat the food particles ?? 3 sufficiently to produce at least one bulky, partially fused particulate product 1. having a volume average particle size in the range of up to about 15 microns, 2. containing approximately 15 to 100 volume% of discrete product particles , generally ellipsoidal, melted, which are substantially vitreous, and because at least the surface portions of the particles are amorphous, and 3. includes about 1% to about 20% of the void volume, based on the volume of the product particles.
5. 5. The method according to claim 4, characterized in that it comprises: A. dispersing the feed particles, solid in gaseous suspension in at least a portion of a mixture of combustible gas, and B. releasing the fuel mixture containing the feed particles suspended to the front of the flame in which the mixture was incinerated.
6. 6. The method according to any of the preceding claims, characterized in that the concentration of feed particles in the fuel mixture is in the range of about 0.05 to about 2, or about 0.2 to about 2, kilograms per kilogram of mixture.
7. 7. The method according to any of the preceding claims, characterized in that it comprises maintaining the front part of the flame and at least a substantial portion of the resulting flame in a wall free zone, which extends downstream from the front, maintaining at the same time the feed particles suspended in a dispersed condition in such zone.
8. 8. The method according to any of the preceding claims, characterized in that it comprises expanding the gases as they progress downstream in the wall free zone.
9. 9. The method according to any of the preceding claims, characterized in that the amount of heat used: for heating, including the preheating, if any, of the feed particles, of any other components of the fuel mixture and of the fuel mixture in yes; for the fusion of the particles; for expansion; and for heat losses, it is in the range of about 278 to about 13,889 kilocalories per kilogram of generally ellipsoidal product particles produced.
10. 10. The method according to any of the preceding claims, characterized in that the amount of heat used: for heating, including preheating if any, of the materials fed different to any volatile substances content of the feed particles, of any other components of the fuel mixture and the fuel mixture itself; for the fusion of the particles; for expansion; and for heat losses, it is in the range of up to 3,889 + (1667 X (Penfield Material Fusibility Index) / 7) Kcal / Kilogram.
11. 11. The method according to any of the preceding claims, characterized in that the amount of heat used: for heating, including preheating if any, of the other materials fed different to any volatile substances content of the feed particles, or any other components of the fuel mixture and the fuel mixture itself; for the fusion of the particles; for expansion; and for heat losses, it is in the range of up to 2.778 + (1191 X (Penfield Material Fusibility Index) / 7) Kcal / Kilogram.
12. 12. The method according to any of claims 1-3 and 6-11, characterized in that the feed particles include sufficient volatile material to generate voids in at least a portion of the product particles fused to provide at least one particulate, bulky product at least partially fused, including at least about 1%, 3% or 5% void volume, based on the volume of the product particles.
13. 13. The method according to any of claims 4-5, characterized in that the feed particles include sufficient volatile material to generate voids in at least a portion of the product particles fused to provide at least one particulate, bulky product at least partially fused , which includes at least about 3% or 5% void volume, based on the volume of the product particles.
14. 14. The method according to any of claims 1-3 and 6-11, characterized in that the feed particles have a volume average particle size in the range of up to about 15 microns and where the product particles are recovered without gaps , so they have a specific gravity lower, at least 1% lower, than the specific gravity of the feeding particles.
15. 15. The method according to any of the preceding claims, characterized in that A. the solid feed particles have a tendency to agglomerate and form lumps when groups of particles are subjected to compaction forces when they are at rest and / or in motion, and B includes applying to the feed particles a quantity of fluidizing agent and / or a quantity or force sufficient to disperse the feed particles in the gas mixture or a portion thereof, so that the difference in particle size of 90 indicated percent of the primary and secondary samples of the feed particles that have been taken respectively before and after the dispersion, the sample of primary particle size that has been vigorously stirred in liquid before measuring its particle size, is in the range of up to about 20% of the primary fed particle size, based on the volume.
16. 16. The method according to any of the preceding claims, characterized in that it includes recovering a product at least partially fused, wherein the excess, if any, of the indicated 90 percent particle size of a sample of product that has been vigorously stirred in liquid, minus the primary particle size of 90 percent of a sample of the feed from which the product has been prepared and which has been vigorously stirred in liquid, is in the range of up to about 30% of the primary particle size, on the basis of the weight or, after making the appropriate corrections for any voids that may be present in the particles of the product, based on the volume.
17. 17. The method according to claim 16, characterized in that the difference in particle size by at least 90 percent is in the range of up to about 10% or up to about 20%.
18. 18. The method according to any of the preceding claims, characterized in that it includes recovering an at least partially fused product, wherein the indicated 90 percent particle size of a product sample is smaller than the one from which the product was prepared. , based on the weight, or afterwards make the appropriate corrections for any voids that may be present in the particles of the product, based on the volume.
19. 19. The method according to any of the preceding claims, characterized in that A. the feed particles, at least a portion of which are irregularly shaped, are present in the fuel mixture in a concentration in the range of about 0.2 to about 2. kilograms per kilogram of mixture; B. the amount of heat used for: 1. heating, including preheating, if any, of the material fed different from any volatile substances content of the feed particles, or any other components of the fuel mixture and the fuel mixture in itself, 2. the fusion of the particles, 3. the expansion, and 4. heat losses, is in the range of up to; 3,889 + (1667 X (Penfield Material Fusibility Index) / 7) kcal / kgra; Y C. the particles of the resulting product exhibit a hollow volume, or reduced specific gravity of the particles of the product in addition to any void volume that may be present, or the presence of some irregular particles, or a combination of two or more of those characteristics.
20. 20. A method according to claim 19, characterized in that the amount of heat used is in the range of up to 2.778 + (1191 X (Penfieid Material Fusibility Index) / 7) kcai / kgram.
21. 21. The method according to any of the preceding claims, characterized in that the concentration of the fed material and the amount of heat energy released are controlled to produce about 1% up to about 3% or about 1% up to about 2% of the void volume in the particles of the product.
22. 22. The method according to any of the preceding claims, characterized in that the feed particles are irregularly shaped and the concentration of material fed and the amount of heat energy released are controlled to produce about 1% to about 10% by volume of irregular particles between the particles of the product. 1¿1 23. The method according to any of the preceding claims, characterized in that it includes: A. releasing the fuel mixture and feed particles suspended to the front of a fuel in which the mixture is incinerated, B. inhibit the agglomeration and / or reagglomeration of the suspended feed particles and distribute the particles present in the suspension of the feed. Substantially uniformly across the front of the flame, C. Maintain the front part of the flame and still a substantial portion of the resulting fiama in the wall free zone, which extends downstream from the front, maintaining at the same time the feed particles suspended in a dispersed condition, D. heating the dispersed feed particles in the wall free zone with the heat transferred to them by incineration of the fuel mixture E. cause at least partial melting of the particles. the particles within at least their surfaces, F. expand the burned gases in the wall-free zone to maintain the p particles separated from each other, while in a softened, semi-fused or fully fused condition, thereby reducing the chances of collision and agglomeration of the particles, and G. maintaining a weight ratio of augmentation particles per unit of volume released in ia area sufficient to produce a bulky, at least partially fused, particulate product, wherein about 15 to 100% by volume of the particulate, bulky product is fused to product particles, vitreous, generally substantially ellipsoidal. 24. The method according to any of the preceding claims, characterized in that it includes heating dispersed feed particles in a wall-free zone with the top transferred to them by the ignition of, and while the particles are entering, the fuel mixture at a temperature of melting in the range of about 500 to about 2500 degrees centigrade or in the range of about 700 to about 2300 degrees centigrade or in the range of about 900 to about 2000 degrees centigrade. 25. The method according to any of the preceding claims, characterized in that the gaseous combustion mixture incinerated to at least partially fused feed particles has a nitrogen content in the range of about 50 to about 60 moi percent, the rest being mainly oxygen . 26. The method according to any of the preceding claims, characterized in that the melting is caused by heating the feed particles with fi les including a front part of the fuel generated by a burner with a fuel mixture, and where all the fuel mixture is heated. In this manner, the total amount of suspended augmentation particles is completely dispersed in that mixture upstream of the front of the flame and the mixture is incinerated while in admixture with the suspended feed particles. 27. The method according to any of the preceding claims, characterized in that the fusion is caused to occur by heating the flame feeding particles including the front of a flame, the particles are uniformly distributed through the front of the flame. Flame as they are released and pass through the front of the flame. 28. The method according to any of the preceding claims, characterized in that the fusion x ¿< i it is effected in a flow of hot combustion gases that move at flow rates of at least about 5 or at least about 20 meters per second. 29. The method according to any of the preceding claims, characterized in that the fusion of the feed particles is carried out with sufficient expansion of the combustible gas mixture for the production and recovery of the product containing, by volume, at least about 15% , or at least about 30%, and up to about 90% or up to about 99%, by volume of generally elliptical, substantially discrete particles. 30. A composition of matter, characterized in that it comprises solid particles, wherein: A. at least a portion of the solid particles are generally ellipsoidal particles that are substantially vitreous, and because at least the surface portions of the particles are amorphous; B. At least a portion of the solid particles, respectively, constitute the particles of the product produced by the at least partial melting of the feed particles while they are flowing in suspension in combustion gases. The volatile material containing the augmentation particles ranges in amount from about 1 to about 25% by weight based on the weight of the feed particles, is derived from, and has chemical compositions that correspond substantially to the chemical composition of, one or more silicas and / or silicates present in mineral deposits found in nature, except that the amount of volatile material in the particles of the product may differ from the volatile material content of the mineral found in the corresponding nature, have a 458 nm color Quest brightness of about 60, have a volume average particle size in the range of up to about 15 microns, and include about 1% up to about 20% of the void volume, based on the volume of the product particles; and C. the composition of the material comprises about 15 to 100% by volume of the generally ellipsoidal particles having such chemical compositions, based on the total volume of the solid particles present in the composition of the material. Z? 31. The composition of matter or method according to any of the preceding claims, characterized in that the particles of the product have a reduced specific gravity, less than the specific gravity of the feed particles, which is at least in part the result of the presence of holes in the particles. 32. The composition of matter or method according to any of the preceding claims, characterized in that the product particles have a reduced specific gravity, less than the specific gravity of the feed particles, which is at least partly the result of the presence of the particles of the constituent phases that are of reduced specific gravity. 33. The composition of matter or method according to any of the preceding claims, characterized in that the dex particles have a reduced specific gravity, less than the specific gravity of the feed particles, which is at least partly the result of the presence in such void particles and the constitutive phases of reduced specific gravity. 34. The composition of matter or method according to any of the preceding claims, characterized L Z I because the particles of the product constitute a voluminous particulate product, having a true, average particle density of at least 1.8, determined in mineral oil. 35. The composition of matter or method according to any of the preceding claims, characterized in that the particles of the product constitute a bulky particulate product having a true, average particle density of up to about 2.1, determined in mineral oil. 36. The composition of matter or method according to any of claims 1-3, 5-29 and 31-35, characterized in that the particles of the product have voids which represent approximately from i to approximately 20 percent of the volume of the particles. particles of the product. 37. The composition of matter or method according to any of the preceding claims, characterized in that the particles of the product have the voids which represent approximately from 1% to approximately 15% or approximately from 1% to approximately 10% by volume of The particles of the product? 38. The composition of matter or the method according to any of the preceding claims, characterized in that the particles of the product have voids representing at least 3% or at least about 5% of the volume of the particles of the product. 39. The composition of matter or method according to any of the preceding claims, characterized in that the particles of the product have voids representing up to about 12% or up to about 15% or up to about 20% of the volume of the product particles. . 40. The composition of matter or the method according to any of the preceding claims, characterized in that the particles of the product are formed from food particles having a volume average particle size in the range of up to about 5, or up to about 10. , or up to about 15, or up to about 20, or up to about 25 microns. i x. xia uu? u? sx ii ii uc mo lci u x? uc? .uuu uu L? receivers, characterized in that the particles of the product are lined from feed particles whose particle size, by volume, 90 percent, is in the range of about 30, or up to about 40, or up to about 60 microns. 42. The composition of matter or method according to any of the preceding claims, characterized in that the product particles, generally ellipsoidal, substantially vitreous, have a volume average particle size in the range of up to about 5, up to about 10, up to about 15, up to about 20 or up to about 25 microns. 43. The composition of matter or method according to any of the preceding claims, characterized in that the product particles, generally ellipsoidal, substantially vitreous, have a volume average particle size in the range of at least about 1 or at least about 2. and up to about 10 microns. 1JU 44. The composition of matter or method according to any of the preceding claims, characterized in that the product particles, generally ellipsoidal, substantially vitreous, have an average particle size in volume at which 90 percent is in the range of approximately 30, up to about 40 or up to about 60 microns. 45. The composition of matter or the method according to any of the preceding claims, characterized in that the particles, generally ellipsoidal, substantially vitreous, have been formed from feed particles without prior conversion of the feed particles in the form of a bulky liquid. 46. The composition of matter or the method according to any of the preceding claims, characterized in that the feed particles include from 1 to 25% by weight of dissolved or combined water. 47. The composition of matter or method according to any of claims 1-3, 6-29 and 31-46, characterized in that the feed particles are composed substantially of any silicas and / or silicates found in nature. x JX 4. The composition of matter or method according to any of the preceding claims, characterized in that the augmentation particles are composed substantially of any silica and / or hydrated silicates found in nature that contain 25% by weight of water. disueita or combined. 49. The composition of matter or method according to any of the preceding claims, characterized in that the feed particles are composed substantially of any silicas found in nature. 50. The composition of matter or method according to claim 49, characterized in that at least 50%, 75% or 90% to 100% by weight of the feed particles are composed of approximately 60% to 100% by weight of silica . 51. The composition of matter or method according to any of the preceding claims, characterized in that the augmentation particles are composed substantially of any silicates found in nature. XJZ o2. The composition of matter or method according to claim 51, characterized in that at least about 50%, 75% or 90% to 100% by weight of the augmentation particles are composed of approximately 60% to 100% by weight of ai less a silicate selected from the group consisting of hydrated calcium silicates and hydrated vitreous reoites, including the periite. 53. The composition of matter or method according to any of claims 1-3, 6-29 and 31-52, characterized in that the particles of the product have chemical compositions, excepted volatile materials, which correspond substantially to any of the silicas and / or silicates found in nature. 54. The composition of matter or method according to any of the preceding claims, characterized in that the particles of the product have chemical compositions, excepted volatile material, which correspond substantially to those of any silicas and / or silicates found in nature that contain from 1 to 25% by weight of dissolved or combined water. bb. The composition of matter or the method of compliance with any of the preceding claims, characterized in that the particles of the product have chemical compositions, excepted volatile material, which correspond substantially with any of the silica found in nature. 56. The composition of matter or method according to any of the preceding claims, characterized in that the particles of the product have chemical compositions, excepted volatile material, which correspond substantially with any of the silicates found in nature. 57. The composition of matter or method according to claim 56, characterized in that the particles of the product have chemical compositions, volatile excepted material, which correspond substantially to the hydrated calcium silicates or hydrated vitreous reoites, including the perlite. 58. The composition of matter or method according to any of the preceding claims, characterized in that the particles of the product are prepared from feed particles, irregularly shaped. XJ o9. The composition of matter or method according to any of the preceding claims, characterized in that the particles of the product include about 15 to about 99%, or about 50 to about 99%, or about 75 to about 99% or about 90 to about 99% in volume of generally ellipsoidal, substantially discrete particles. x? 60. The composition of matter or method according to any of the preceding claims, characterized in that the particles of the product have been formed by melting the feed particles containing 15 crystalline structure and where substantially all the crystal structure present in those particles has been destroyed during the fusion operation. 61. The composition of matter containing solid particles according to claim 30, characterized in that it is useful for applying to human or animal body parts. 62. The composition of matter according to claim 25, characterized in that approximately XJO 90 to 100% by volume of the solid particles have diameters, on average, in the range of up to 10 micrometers. 63. The composition of matter according to claim 61 or 62, characterized in that approximately 90 to 100% by volume of the solid particles are generally ellipsoidal or substantially spherical. 64. A pharmaceutical or cosmetic preparation, characterized in that it contains solid particles according to any of claims 61-63, in the form of a fluid or dispersible material. SUMMARY OF THE INVENTION Methods are described for producing bulky, particulate material, which includes generally ellipsoidal, solid particles. Irregularly shaped feed particles with average particle sizes of up to 25 microns are dispersed based on the volume in at least a portion of a combustible gas mixture by the application of force and / or fluidizing agents. The fuel mixture with particles in suspension is then released, while controlling the agglomeration or reagglomeration of the particles, to at least one front part of the flame. There, the mixture and the suspended particles are distributed evenly across the surfaces and pass through the front of the flame with a high concentration of particles in the mixture. In this way the front part of the flame and the resulting flame with the suspended particles are located in at least one area "free of the wall". In such an area the flame can expand while the particles are kept dispersed and heated, with controlled and highly efficient application of heat energy. At least partial fusion occurs within at least the surface of the particles at high thermal efficiencies, while the agglomeration of the particles during the fusion is inhibited.