Abstract: An apparatus and process for separating waste material requiring use of ground water for processing in a wet mill a drum separator in combination with purification and recycling, routing recycled water to a biomonitoring fish pond and use of a system wash water for washing for processing in a wet mill sanitizing of refuse collection vehicles. The groundwater is obtained from an aquifer underlying and containing leachate from a landfill, thereby solving environment problems.

Abstract: A process for the production of a coal-water mixture, which comprises dry-pulverizing coal under supply of hot air to form pulverized coal in which the proportion of particles having a particle size smaller than 200 .mu.m is at least 90%, in which the proportion of particles having a particle size smaller than 10 .mu.m is 10 to 60%, and making the pulverized coal and the hot air sucked in a mixed-air water jet stream.

Abstract: A system for separating contaminants from the plastic flake obtained by granulating synthetic plastic containers and products, which have contaminants bonded thereto, has a cryogenic housing for receiving the flake and a transport mechanism incorporated with the housing for moving the flake in a flow stream through the housing. The flake is mixed with a cryogenic medium at a subzero temperature and an impeller receives the frozen flake in a flow stream. An impact wall is provided outboard of the impeller and the impeller is rapidly revolved to radially separate the flakes and hurl the flakes individually at the impact wall with sufficient force to break the bond between the flakes and contaminant.

Abstract: Process for the continuous drying of hydrophilic polymer gels in a cylindrical dryer with a high speed rotor which conveys the material to be dried through the dryer and prevents agglomeration.

Abstract: The apparatus to put the process of the invention into practice comprises a silo 1 to dispense fat (oil), a duct 2 to feed in lime and optionally inert additives, a mixer 3 provided with a stirrer, at least a charging pot 4, a pocket vessel 5, a hopper provided with a distribution blade 6, a conveyor belt 7 continuously operating internally of the baking furnace, a baking furnace 8, a grid-type conveyor belt 9, a first crusher 10 and a mill 11. The powder lubricant obtained by said continuous process also has the advantage of exhibiting a better morphological appearance, more hardness and improved adhesion to the substrate to be lubricated.

Abstract: Solid particles of microscopic size are mixed in a nitrogen atmosphere at conditions of pressure and temperature such that at least a monolayer of nitrogen molecules is adsorbed on the particle surfaces but at conditions at which liquid nitrogen cannot exist in the mixture.

Abstract: The present invention relates to a process for careful grinding and simultaneous drying of moist cellulose ether products wherein a moist cellulose ether is introduced by means of a transport gas into a circular space. The moist cellulose ether is impact-comminuted while being circulated in that space, and the product is simultaneously friction-comminuted in a direction opposite to that of the impact comminution. The peripheral speed of the comminution stages, which operate in opposite directions, is regulated to such a value that the resulting grinding energy dries the product to a predetermined residual moisture content. The ground material is conveyed by the gas stream introduced into the comminution space, and the ground material is then separated from the gas stream. If desired, the ground material is subjected to selective screening.

Abstract: Hazardous substances are separated from used foundry sand by means of a triple fluid bed thermal reactor, second stage sand cooler and third stage pneumatic attrition scrubber. Temperatures in each of the reactor's beds are precisely controlled, depending upon the nature of the sand being treated, so that hazardous substances can be separated and disposed of, rather than fixing the substances onto the sand grains in insoluble form.

Abstract: This invention relates to an improved method and apparatus to effect the separation of component fractions from paper-containing and plastic-containing waste materials. This method and apparatus accepts materials of widely varying characteristics such as paper, plastics, glass, metal, food wastes and other materials to be inserted en masse into a rotating vessel equipped with lifting paddles and directional flighting. In this way the intimate contact of materials with moisture and heat is accomplished, thus effecting the repulping of paper materials. The repulped materials, as a result of directional tumbling, are dispersed throughout the vessel. Because of the repulping of the pulpable materials, size reduction of the randomly large and odd-shaped pulpable material is accomplished. By virtue of the size reduction of the large and odd-shaped pulpable materials, the non-pulpable components are freed of the particle shapes and surfaces that affect separation.

Abstract: A method of making high-purity fine particles of reactive metals, reactive especially in terms of their inclination to form hydroxides, comprises the steps of: preparing an inert gas atmosphere within which to manufacture the particles; reducing the moisture remaining in the inert gas atmosphere to an extremely low level; pulverizing the reactive metal within the moisture-free inert gas atmosphere; and collecting and sealing the product particles of reactive metal in a storage container in the same moisture-free inert gas atmosphere.

Abstract: Fluidized-bed counter-jet mills are gas-jet mills with which extremely fine milling results can be produced with very little wear and tear. An improvement in the milling results can be achieved by cooling the gas jets with a refrigerant, but the improvement that can be achieved is not substantial and the consumption of refrigerant is very high. In order to lower the consumption of refrigerant while considerably improving the fineness of the milled material, the coarse material which is separated by the grader of the mill is cooled by the refrigerant within the fluidized-bed counter-jet mill and fed back into the milling chamber. Liquid nitrogen is the preferred refrigerant with which the sump of the mill is cooled.

Abstract: A process for crushing a hafnium (Hf) crystal bar comprises the steps of maintaining the Hf crystal bar at an extremely low temperature by holding the crystal bar in contact with a cryogenic refrigerant and crushing the crystal bar at the extremely low temperature by clamping and compressing the crystal bar between nickel (Ni)-base superalloy members. An apparatus for crushing the Hf crystal bar comprises a Ni-base superalloy-made container for containing the cryogenic refrigerant, the container having a bottom portion capable of being selectively opened and closed, a heat insulator for covering the container filled with the cryogenic refrigerant so as to maintain the interior of the container at the extremely low temperature, Ni-base superalloy-made pressing terminals for clamping the Hf crystal bar therebetween in the container, and a pressing device for exerting pressure on the pressing terminals so as to compress and crush the Hf crystal bar.

Abstract: Described are deodorant and/or antiperspirant vehicles which contain fragrance-containing polymer pellets containing 1 to 80% fragrance, the polymeric pellets produced by means of cryogenically grinding an extruded mixture of perfume composition and polymer.

Abstract: The process for producing crushed zirconium sponge having particle configurations which enhance its compactability, wherein conventionally produced, as-reduced, non-sintered zirconium sponge pieces are loaded into a vacuum furnace, the furnace is heated under partial vacuum at a temperature of up to about 400.degree. C. for a sufficient period to essentially demoisturize and degas the sponge, the temperature is raised to at least about 700.degree. C. and the vacuum terminated, H.sub.2 is fed in a carefully controlled manner into the furnace over a period of several hours in a total amount comprising from about 0.05 to about 0.8% by weight of the sponge, the furnace is cooled, the cooled sponge is pacified, the sponge is removed from the furnace and crushed, the crushed sponge is loaded into a vacuum furnace, the furnace is heated at from about 950.degree. C. to about 1100.degree. C.

Abstract: A material treating apparatus is used for treating powdery, granular and conglomerate materials. The material treating apparatus includes a material supply apparatus for transferring the materials to a predetermined position, particularly for supplying the materials to an automatic crusher. The material treating apparatus includes a crushing system having a crushing vessel transferring unit. The material treating apparatus further includes an analysis sample transferring apparatus particularly suitable for transferring samples formed by a press to a fluorescent X-ray analyzing apparatus. The material treating apparatus includes a fluorescent X-ray analyzing system which is capable of automatically analyzing samples of various kinds. An analyzing method is carried out by the use of the above material treating apparatus. The analyzing method includes a method of vitrifying an inorganic material, which is preferably used for obtaining samples to be analyzed by the X-ray fluorescence analysis.

Abstract: A mixture of unlike particulate solids is dispersed in liquid nitrogen to form a slurry. The slurry is then subjected to shear and impact forces of sufficient intensity and duration to break up agglomerates, to comminute at least the larger particles, and to obtain a randomly mixed homogeneous suspension. The suspension is thereafter stabilized by removal of liquid nitrogen to form a past or powder which may be further processed into shapes by extrusion or molding. One preferred embodiment utilizes a batch-to-continuous process for the compounding of rubber with carbon black and other additives.

Abstract: A process and apparatus for granulating slag in which molten slag is charged into a drum and is solidified and granulated therein on cooled surfaces. To ensure a rapid cooling at a high thruput rate, the molten slag is applied to the inside surface of a drum, which rotates on a horizontal axis and has a cooled shell, and the solidified film of slag is mechanically detached from the inside surface after about three-quarters of a revolution of the drum and is discharged.

Abstract: In a process of fragmenting and segregating metallic components fabricated from different aluminum alloys, a method of removing tramp impurities therefrom is provided. The method comprises the steps of providing a feedstock comprised of the metallic components having mixed therewith tramp impurities, the alloys having different incipient melting temperatures. The feedstock is heated to effect incipient melting of the component having the lowest incipient melting temperature and is then agitated sufficiently to cause the component having the lowest incipient melting temperature to fragment. The agitation also causes the fragmented component to scour tramp impurities from the unfragmented feedstock. The fragmented components and tramp impurities are segregated from the unfragmented feedstock and fragmented components are separated from the tramp impurities.

Abstract: A syringe disposal apparatus has a portable collection unit and a process unit. The collection unit has an in-feed mechanism to allow syringes to be introduced into the collection unit; and an interlock mechanism suitable for removably securing the collection unit to the processing unit and emptying the syringes from the collection unit into the processing unit. The processing unit contains an interlock mechanism suitable to activating the collection unit interlock mechanism; a grinder suitable for grinding the syringes into particles of metal and plastic; and a crucible assembly suitable for heating these particles above the melting point of plastic, and then cooling to produce a solid puck of plastic in which the metal particles are suspended and encapsulated.

Abstract: A method for beneficiating a coal refuse feed stream which includes agglomerated carbonaceous and clay particles. The feed stream is rapidly heated to volatilize moisture. Heating is carried out in a manner to produce abrasive commutation and sub-divide particles by volatilizing the moisture. After deagglomerating the feed stream, the discreet particles essentially consisting of carbonaceous particles and clay particles are separated to form a plurality of differently sized classifications of granular particles. A carbonaceous particle fraction essentially comprised of granular particles having a particle size greater than about 2 microns is recovered to form one fraction and a minus 2 micron fraction is classified to separate particles from the component gas. In one embodiment, a dust laden gas fraction is treated in an air classifier to form a coarse particle fraction and a fine particle fraction. The recovered coarse particle fraction can be used as a carbonaceous fuel.

Abstract: A method for pulverizing a material comprises having the material packed into an ice tube and frozen to form a composite ice pillar. The pillar is ground from one end thereof on a grinder. The outer tube serves to prevent the material from being scattered prematurely before being sufficiently pulverized. This method assures pulverization to a fine powder, at one operation, and a low cost.

Abstract: A system for collecting, drying, and comminuting garbage. The garbage is collected and introduced into a hopper. A plurality of heat lamps and sandblasting nozzles are provided on the walls of the hopper. The garbage is dried and comminuted in the hopper. A mesh conveyor is provided for filtering out particles smaller than sand which are delivered by a conveyor for further waste disposal. Particles and sand which do not pass through the mesh conveyor are fed back and delivered under pressure to the sandblasting nozzles.

Abstract: A method for lowering the risk of contamination during comminution of solid silicon fragments produces in a first step a temperature gradient in the solid silicon fragments. This temperature gradient results from the action of heat applied from the outside. A second temperature gradient is then produced, whose direction is rapidly at least partly reversed in a second step. This treatment effects a decompacting which makes it possible to use, in a subsequent mechanical comminution step, tools whose contact surfaces are composed of silicon or of hard materials, for example, based on nitride or carbide. The product obtained is remarkable for its uniform grain size distribution and also for its high purity in fine grain size categories. In addition, the low forces required for the comminution makes possible a longer service life for the tools used.

Abstract: A process and apparatus for the low temperature comminution of tires includes the separation of the tires into tire portions including tread portions, sidewall portions and bead portions. The tire portions are cooled and crushed to form rubber granules and scrap material. The rubber granules are sorted from the scrap material in a process that includes the step of suspending the granules in a moving stream of low temperature gas. The stream of gas and rubber granules is impacted on a solid surface to grind the granules. The low temperature gas is preferably recycled and cooled by heat exchange with another circulating low temperature gas such as nitrogen.

Abstract: The plastic syringe destruction device employs a cylinder and piston compaction unit together with heat to thermally smash plastic syringes into a compacted mass or slug. During compaction, the syringes are heated to temperatures between 100.degree. C. and 200.degree. C. to bring about melting of the syringes as well as sterilization. A removable transparent cover is also provided to permit only individual depositing of syringes into the cylinder when the main cover is in an opened position. A water injector nozzle is also provided as an option to permit compaction in a dry or wet state.

Abstract: Material is comminuted in a substantially dry state in a chamber (4) as a result of agitation by a rotor. During the process, gas is admitted to the chamber (4) through a foraminous base (8) to flow upwardly in a uniform manner across the cross-section of the chamber. Pulses of gas are directed periodically at the material through inlets (15) to prevent agglomeration of the material. The pressure of the gas admitted through the inlets (15) is higher than that admitted through the foraminous base (8). Surface active agents may be added to the material, also to prevent agglomeration, as well as, or instead of the use of pulsed gas.

Abstract: A fluidized granulating and coating apparatus having a cylindrical treating vessel provided with at least one spray nozzle, at least one air supply duct and one exhaust duct, and a downwardly converging frusto-conical portion. The spray nozzle is disposed at a position below the interface of the fluidized particles within the region of the frusto-conical portion. At least one compressed air nozzle is disposed at a level below the interface of the fluidized particles and within the range of the frusto-conical portion. Disclosed also is a fluidized granulating and coating method which makes use of this apparatus. With the apparatus and the method of the invention, it is possible to produce granular products such as a slow-effecting or long-lasting pharmaceutical product with a high quality and homogeneity at a high yield, by coating cores of spherical granules with a coating composition containing the medical component of the desired property.

Abstract: Pieces of aramid cloth impregnated with a blend of phenolic and polyvinyl butyral resins are cryogenically chilled to the point of embrittlement in a liquid nitrogen bath and then fed to a rotary impact mill to comminute the pieces into a fibrous material suitable for use in brake linings or other friction applications. The rotary impact mill is chilled by cold gaseous nitrogen from the liquid nitrogen bath, the flow of which is controlled in response to a thermocouple disposed near the mill exit.

Abstract: A toner for producing electrostatic latent images is produced by classifying a pulverized feed material into a coarse powder and a fine powder in a first classifying means, pulverizing and recycling the coarse powder to the first classifying means, introducing the fine powder into a multi-division classifying chamber divided into at least three sections where the fine powder is classified into at least a coarse powder fraction, a medium powder fraction and a fine powder fraction. The medium powder fraction is recovered to provide a toner. The coarse powder fraction is recycled to the first classifying means.

Abstract: A method for treatment of mixed wastes containing various plastics, such as municipal solid wastes, in which mechanical agitation and heat distortion of plastic films cause rupture and spilling of the contents of plastic film containers in the wastes. The wastes are introduced into a processing unit with means of heating and mechanical agitation of the contents. By the method in this invention, the plastics are separated and recovered as a mixture that may be recycled as a composite plastic used in the manufacture of various products or that may be further separated into identifiable types of plastics for recycling. The quantity of plastics recovered from MSW is greatly increased compared to previous processes using steam heat to achieve separation of the components of such mixed wastes.

Abstract: The invention relates to the use of a fraction of hardened particles of an elastomer material of limited particle sizes between 0.1 and 1 mm, preferably between 0.3 and 0.7 mm. The order of magnitude of the admixture to every 100 parts of unhardened elastomer material lies at 5 to 60 parts, preferably 20 to 40 parts. The admixture of the particles to the elastomer material is effected before the elastomer material hardens and is done to produce a defined, non-smooth surface in end products made of elastomers.

Abstract: A method for converting cobalt to cobalt powder is disclosed which comprises heating a starting mixture of cobalt and zinc in a non-reacting atomosphere at a first temperature of below the boiling point of zinc up to about 900.degree. C. in a non-reacting atmosphere for a length of time sufficient to cause the alloying of a portion of the zinc and cobalt, with the weight ratio of zinc to cobalt being less than about 10. The temperature of the resulting partially alloyed mixture is slowly raised to a second temperature of from about 900.degree. C. to about 960.degree. and is maintained for a time sufficient only to form a reaction product in which essentially all of the cobalt is alloyed with zinc and to keep the evaporation of zinc to a minimum. The reaction product is then heated at a pressure below atmospheric pressure at a third temperature of no greater than about 950.degree. C.

Abstract: A process for working up household, industrial and other similar waste for the recovery of a fibrous and/or granulated material, in which the waste material is subjected to preliminary comminution, magnetic separation, classification, drying and fractionation, wherein the light fraction resulting from the classification carried out after the magnetic separation is subjected to secondary comminution by cutting, and the heavy fraction to a predominantly granulating secondary comminution and thereafter both comminution products are recombined, dried and fractionated into fibrous matter and granulated material, is to be simplified, and in particular the costs reduced. This is achieved in that before the secondary cutting comminution appliance at least one part stream or the whole stream of the light fraction is diverted and fed directly and/or after comminution in a further comminution unit to further utlization. A device for carrying out the method is also proposed.

Abstract: Used products, which would otherwise be disposed of as waste, are subjected to low temperature lowering the temperature of the product to approximately the temperature of crystallization of the components thereof. The product at this lowered temperature is then crushed sufficiently to cause the components thereof to release sufficiently to be subsequently separated according to material. The separation steps can include subjecting the crushed material to magnetic or electrostatic fields, air flows caused by either pressurized air or vacuums, and mechanical separation with vibratory screens and rakes. The materials of the original product are sufficiently separated to enable them to be recycled into usable product. The particular example cited relates to vehicle tires with the materials recovered including rubber, fiber and metal bands.

Abstract: The apparatus operates to supply the air requirements for grinding a fuel material to the mill to guarantee the correct particle size and to decouple from the air emitted from the grinding apparatus a certain proportion so the combustion of the ground fuel material will be conducted at a ratio of less than the usual 3 to 1 ratio of air-to-fuel so the combustion can be controlled to reduce the nitrous oxide emission, the air that is decoupled is returned to the grinding apparatus with a supply of make up air that is heated for purposes of drying the material in the grinding apparatus.

Abstract: A method of controlling a bowl-mill crusher that has cylinders that remain in one position and roll over a rotating bowl with a predetermined force. Raw coal and primary air are supplied to the crusher and the crushed coal is removed from the crusher along with the primary air through a separator and supplied to burners through a pulverized-coal line. The pressure of the primary air where it enters the bowl-mill crusher is controlled in accordance with load and in a manner so that the pressure of the crushing cylinders against the bowl is decreased in a predetermined manner when the desired load-dependent level is not attained and is increased when the level is exceeded.

Abstract: Animal or plant derived materials are prepared for extraction of desired substances therefrom by grinding said materials at or below their Brittleness Temperature. This treatment allows fracture of the materials into small particles with high surface area to volume, as well as high volume to mass ratios, and disrupts membranes of tissues, organs, cells or organelles which would otherwise prevent or limit separation of desired biomolecules.

Abstract: A mechanical disintegration is effected in which substantially only the metal sheath of the small batteries is torn apart. The crushed material is roasted at 500.degree. to 1000.degree. C. in a state of motion in an oxidizing atmosphere and the volatilized mercury is recovered from the exhaust gas. The roasted material is separated by sieving and magnetic separation into an iron-containing scrap fraction, a brass-containing scrap fraction and a collectable fraction, which contains manganese, zinc and silver.

Abstract: Zirconia ceramics containing substantial amounts of metastable tetragonal phase crystallites, so that they are tougher than most other ceramics, can be completely comminuted to powders, without applying any mechanical force, by treatment with water or steam at temperatures well above room temperature. This type of comminution is particularly useful for small, often hollow, spheres produced by rapidly solidifying melts of zirconia and a stabilizing oxide such as yttria. These spheres can be almost completely comminuted to a size suitable for wet vibratory milling by treatment for twenty-four hours at 250 C under sufficient steam pressure to maintain some liquid water in equilibrium.

Abstract: A waste material processing facility reduces the volume of waste material and produces an end product capable for use as construction building material. The waste material processing facility includes a conveyor belt for conveying the waste material to a shredding facility. The shredding facility controls the dimensions of the waste products being processed. An incinerator, for low heat incineration of the shredded materials includes pollution control devices for removing contaminates from the gases resulting from the incineration process. A facility is provided for solidifying, compacting, molding and glazing the char resulting from the incineration process into construction grade blocks.

Abstract: A rice-hull-ash filter aid is produced by burning rice hulls to produce ash, grinding the ash to reduce its particle size, classifying the ground ash to remove oversized particles and collecting the remaining particles.

Abstract: A process and apparatus for releasing blossom pollen from its outer skin by a combination of drying and size reduction pressure treatment steps.

Abstract: A process for increasing tree unit shelling efficiency includes a means of temporarily hardening the kernels of unshelled nuts to increase the efficiency of conventional nut hulling and/or shelling means. Quick freezing is used to sufficiently lower the temperature of the kernels of unshelled nuts to freeze the liquid matter contained in the kernels with minimal ice crystal formation. A higher percentage of nut kernels remain intact during hulling and/or shelling. The hulls and/or shells of the nuts remain substantially unaffected by quick freezing.

Abstract: For reducing the specific energy outlay in the grinding-drying of damp initial material, a circulating grinding system including a comminution machine, particularly an impact hammer, which is followed, via a sifter, by a high-pressure roll press operated in accord with the principle of product bed comminution, whereby the product admission of an impact hammer mill is connected to the feed for fresh initial material and the product discharge of a roll press is in communication with a product admission and/or with a product discharge of an impact hammer mill.

Abstract: Apparatus and method for handling molten slag, in which the slag is delivered from a furnace to a cooling conveyor by a reciprocating spout, driven in a horizontal plane to provide a stream of molten slag in a substantially sinusoidal pattern to the conveyor. The conveyor is sloped to provide gravity flow from an input end to an output end, and vibration is imparted to the conveyor for separating the molten stream of slag into pieces of slag and for propelling slag from the input end toward the output end. Cooling is provided by a water jacket around the sides and bottom of the conveyor, sufficient substantially to solidify the pieces of slag before they reach the output end. Further cooling may be provided by a spray bar, positioned above the conveyor, which provides a stream of cooling water to the surface of the slag. A water bath is disposed to receive pieces of slag dispensed from the output end of the conveyor, further cooling the slag to about 200 degrees Centigrade.

Abstract: Crushed particles of coal, ores or industrial minerals or rocks are comminuted by feeding them through a feeder (14) into a cyclic stream (19, 22, 38, 39, 41) of cryogenic process fluid such as liquid carbon dioxide and conducting the process stream with the entrained mineral particles to a comminuter (17) and through a zone therein of mechanically generated high frequency vibratory energy, preferably ultrasonic. The comminuter (17) may be multistage with means for re-cycling oversize mineral particles and, after leaving the comminuter (17) the process stream (38) is conveyed to a separator (18) for extracting the comminuted particles and re-cycling the cryogenic fluid to the feeder (14). The low temperature of the process stream is maintained by refrigerating means (16) and losses of the fluid are made up by supplementary fluid fed to the stream.

Abstract: A method of making superalloy scrap friable in order to allow greater recovery of metal values therein is disclosed whereby the scrap is treated with zinc vapor. After exposure to the zinc vapor, the metal scrap becomes friable so that it can be easily crushed. Thereafter, the metal values, particular of cobalt and nickel, can be easily recovered. The process can be made continuous by recovering and reusing the excess zinc vapor used in the treatment.

Abstract: A method for reclaiming green sands having a wide range of moisture and temperature conditions involves processing such sands in a single reclaimer unit to produce free flowing reclaimed sand adapted to pass through a 20 mesh screen and having a temperature preferably no greater than about 120.degree. F. The method involves effecting attrition of a batch of molding sand supplied to the reclaimer unit, applying a vacuum exhaust to the unit primarily to remove a calcined clay binder and water vapor therefrom, sensing the means temperature of the sand, and selectively adding moisture or heat to the sand as required to produce reclaimed sand having predetermined moisture and temperature conditions allowing such sand to be immediately screened of extraneous materials and passed to a mulling device or remixer. The rate of addition of moisture, if any, and the flow of exhaust air through the unit are controlled in order to prevent condensation in the exhaust conduit and dust collection devices.

Abstract: A method and apparatus for recycling asphalt shingles in an asphalt plant which heats and dries aggregate and mixes the heated and dried aggregate with liquid asphalt to form an asphalt paving composition. The shingles are comminuted to particles of a size which can be easily flowed and metered, and the shingle particles are introduced into the asphalt plant such that they are heated to melt the asphalt in the shingle particles. The aggregate, heated shingle particles, and liquid asphalt are thoroughly mixed to form an asphalt paving composition.

Abstract: According to the invention, after having previously crushed and ground a starting material containing silicon carbide, the latter is treated by separation in a dense medium, such as one comprising ferrosilicon or a suspension of magnetite in water. There is obtained a concentrate of silicon carbide without having to use the step of manual sorting.