Abstract: A process and device for the removal of arsenic, tin and antimony from crude lead by industrial oxygen is disclosed in which the oxygen is introduced into a turbulent fluid stream of lead restricted in a limited volume. The oxygen containing fluid stream passes into a larger volume in which the compounds which are to be separated float on the surface in the form of oxides and run off from the surface. The device includes two cylinders of different volume and one within the other. The cylinders are immersed at different depths in molten lead in the smelting crucible, a steam of fluid lead is introduced in the smaller cylinder by a lead pump and oxygen is introduced into this fluid lead stream.

Abstract: The filtration of molten ferrous metal is accomplished by providing a porous ceramic filter preferably comprising particles of alumina and partially stabilized zirconia that are spaced by interconnected cells to form circuitous and tortuous pathways throughout the ceramic body. The filter is a disc-like structure that can have different surface configuration such as corrugations or a waffle design. The filter can be flat-surfaced with an array of cylindrical openings or counterbored openings extending completely through the filter, or with openings extending partially into the filter from the upper and lower sides of the filter. Several relatively thin filters can be arranged in tandem, if desired.

Abstract: A filter for use in the filtration of molten metals comprises a ceramic foam having a gasket made from fibrous material surrounding its peripheral surface and a metallic foil, such as aluminum foil, fixed to the gasket, for example by means of an adhesive, around the outer peripheral surface of the gasket.

Abstract: The present invention relates to a ceramic body suitable for use in molten metal filtration applications having a built-in preheat indicator and method for forming such a ceramic body. The preheat indicator comprises a dye having a burnoff temperature substantially equal to the desired preheat temperature applied to a surface of the ceramic body. In a preferred embodiment, the dye comprises an aniline dye such as Backmeier's crystal violet.

Abstract: Apparatus for pouring molten metal comprises a cold crucible 15 which has a recess adjacent its top and a pouring spout 16 positioned in the recess just below the level of the surface of the melt. The recess defines a lip above the spout which helps to ensure that there is a constant pressure head above the spout. Pivotally mounted on the lip, and biased to assume a horizontal position irrespective of the angle of tilt of the crucible is an induction coil 21. The coil induces currents in the surface of the melt and thereby moves the dross away from the pouring spout. The crucible 15 pours into a constant head hopper 22 and the opening and closing of the crucible pouring spout 16 and the angle of tilt of the crucible are controlled to ensure constant pressure head in the hopper.

Abstract: A method and apparatus is provided for filtering liquid-phase metal. The method comprises the steps of: (1) establishing a bath of liquid-phase metal; (2) providing a conduit connecting the bath to a filtering means; and (3) producing a magnetic field within the conduit to produce axial flow of the liquid-phase metal within the conduit to transfer at least a portion of the liquid-phase metal to the filtering means and cause at least a portion of the liquid-phase metal to flow through the filtering means.

Abstract: The present invention relates to wax impregnated filters for use in investment casting applications and a method for forming them. The filters are characterized by a wax impregnated ceramic substrate, wax layers bonded to two opposed surfaces of the substrate, and peripheral edges having exposed ceramic surfaces which can be adhered to the ceramic liner of an investment casting apparatus. The method comprises providing a sheet of ceramic foam filter material, impregnating the sheet with sufficient liquid wax to form a wax layer of desired thickness bonded to each of two opposed surfaces of the sheet, allowing the wax to solidify, and precision cutting the impregnated sheet into filters having a desired set of dimensions. The method further comprises exposing the peripheral edges of each filter to allow the ceramic shell building or liner in the investment casting apparatus to bond directly to the filter.

Abstract: A metal having a high purity is prepared by immersing a hollow rotary cooling member in a molten metal containing eutectic impurities and rotating the cooling member while supplying a cooling fluid to the interior of the cooling member, whereby the high-purity metal is caused to crystallize out on a metal deposition area of the peripheral surface portion of the cooling member present under the surface of the molten metal, the metal deposition area being the peripheral surface of at least a part of the entire portion, present under the melt surface, of the member. When the purified metal is caused to crystallize but by rotating the cooling member, a flow of molten metal having a downward velocity component is produced in the vicinity of an upper part of the entire portion, present under the melt surface, of the cooling member.

Abstract: The present invention relates to an improved molten metal filtration system. The system comprises at least one filtration assembly positioned within a filter chamber intermediate a molten metal inlet and a molten metal outlet and a dam wall positioned intermediate each filtration assembly and each molten metal outlet. Each dam wall prevents the initial molten metal used to prime the filter(s) in each filtration assembly from proceeding directly to the outlet. Instead, the dam wall collects the initial molten metal and forms it into a pool of heated molten metal. This pool has been found to reduce the amount of heat loss during the filtration process. A process for using the filtration system of the present invention is also described.

Abstract: A molten metal pump includes a filter that prevents ingestion of foreign material such as dross from molten metal within which the pump is immersed. The filter is a large structure that is secured to the base of the pump surrounding the pump's inlet. The filter forms a cavity adjacent the pump's inlet. The ratio of the surface area of the filter to the inlet area of the pump is very large; the filter has a low porosity while maintaining a high flow rate for the pump.

Abstract: An improved apparatus for recovering liquid aluminous metal from hot, aluminous skim comprising a combination of an open-one-end bowl to hold the hot skim and retain the residue after centrifuging, a bowl cover latchable to said bowl and with means to provide one or more controlled peripheral openings between said components which together form a skim centrifuge body, which centrifuge body is suspended and rotatable from a loosely fitting, mating linkage which has arcuate mating surfaces, the upper connecting part of which is connected to a source of rotation said rotational force source being provided with a non-rotating reaction and support surface which is preferably separated from the rotating load-carrying member by at least two, concentric bearings of replicate function and the apparatus preferably further consisting of a liquid collection means which surrounds horizontally the suspended centrifuge body during rotation.

Abstract: Shaped, porous filter members having a size and shape adapted for the filtration of liquid metals, e.g., the configuration of a honeycomb, are comprised of a porous alveolar ceramic material including from 10 to 20% SiO.sub.2, from 50 to 60% Al.sub.2 O.sub.3 and from 20 to 40% ZrO.sub.2, each percentage being by weight with respect to the total weight of said oxides, said Al.sub.2 O.sub.3 and SiO.sub.2 being present in the form of mullite, 3Al.sub.2 O.sub.3 /2SiO.sub.2, and the combined weight of the zirconia and mullite comprising at least 90% by weight of said alveolar ceramic material.

Abstract: A system which provides an improved design capable of removing liquid phase inclusions by combining a filter and an electromagnetic separation device through the addition of baffles to a chamber where molten metal is flowing under the influence of an applied electromagnetic field. The placement and the shape of the baffles reduces vorticity effects of the magnetic field in each of the baffled compartments and eliminates the convective flow resulting from the electromagnetic force in order to trap inclusions against the walls of the baffles.

Abstract: This invention relates to a cold trap for collecting impurities from liquid, which comprises a mesh screen and a spacer mesh having higher strength and wider mesh holes than that of the mesh screen interposed between the windings of the mesh screen. According to the present invention, since the spacer mesh supports the mesh screen over the whole surface thereof so that the mesh screen is protected free from break or deformation, the stiffness and collecting efficiency of the mesh section can be maintained prolongedly.

Abstract: A device for detecting slag flowing with a stream of molten metal dischar through an outlet opening in a metallurgical vessel includes a sensor positioned in the area of a base plate of the vessel to surround the stream of molten metal without being contacted thereby. The sensor has a sending coil and a receiving coil associated with a reference coil. At least the sending and receiving coils are positioned within a housing formed of a non-magnetic material. The housing encompasses the coils and defines therearound a protective casing that alters electromagnetic fields emanating from the base plate and the stream of molten metal and that is resistant to mechanical stresses.

Abstract: An improved vortex inhibitor for separating slag from molten metal during the discharge of molten metal through a nozzle includes a uniform castable refractory body with a regular pyramidal shape. The tapered body includes swirl obstructing surfaces extending along its length and is geometrically proportioned so that the center of gravity is closer to the apex than the center of buoyancy of the body. Preferably, the outermost parts of the base intersect a circle whose diameter is larger than the diameter of the nozzle opening and defining a base length dimensionally fixed with respect to the base length within a predetermined range. Preferably, the longitudinal height is in the range of 0.5 to 1.0 times the diameter of the circumscribed circle. A modified, spherically configured body which can be rolled into position also is geometrically proportioned to keep the center of gravity spaced from the center of buoyancy and closer toward the apex of the modified shape.

Abstract: A getter trap to remove hydrogen and oxygen from a liquid metal, such as liquid sodium, includes an elongated, closed housing having an inlet at one end thereof and an outlet at the other end. A getter material is randomly diposed within the housing comprising a zirconium-containing substrate of hollow, tubular sections having a coating thereon of a gettering alloy of zirconium, vanadium and iron. As a liquid metal flows through the inlet into the housing and through the getter material, and is discharged from the housing through the outlet, hydrogen and oxygen impurities are removed from the liquid metal. The getter trap is particularly useful in an improved liquid metal cooled nuclear reactor system.

Abstract: A method of operating a flash smelting furnace which includes a reaction shaft, a concentrate burner disposed at the top of the reaction shaft, a settler disposed with one end thereof connected to the lower part of the reaction shaft, an uptake disposed as connected to the other end of the settler, and at least one lance pipe disposed through the ceiling of the settler between the reaction shaft and the uptake and adapted to permit forced supply of at least powdery raw materials and a reaction gas into the melt in the settler includes the steps of blowing the powdery raw materials containing only a small amount of incombustible substances and the reaction gas into the reaction shaft through the concentrate burner, blowing powdery raw materials containing at least incombustible substances through the lance pipe, and employing means capable of at least retaining the heat of the melt.

Abstract: The apparatus for filtering scraps of light metal for regeneration thereof comprises an upper vessel having heating means for maintaining the scraps, charged therein for the filtration thereof, at a predetermined temperature so as to melt the same or for maintaining molten metal, supplied therein after having been molten, at the predetermined temperature, a lower vessel having heating means, filtering means interposed between the upper and lower vessels, temperature controlling means for both the heating means, pressurizing means connected to the upper vessel and/or depressurizing means connected to the lower vessel, and a lifting/lowering device for the upper vessel and/or a transporting device for the lower vessel. The apparatus may further comprise an inner vessel for receiving molten metal having been passed through the filter means, which is freely removably arranged in the lower vessel.

Abstract: A device for the separation of slag insuring its retention in a tapping converter such as used in the steel industry consists of a closure having a specific gravity lower than that of the steel produced in the converter but higher than that of the slag provided with an elongated depending hexahedron shaped extension that tapers downwardly to a blunt end and acts as a vortex inhibitor within the swirl of molten metal occuring during the tapping of the metal to avoid formation of a suction funnel which typically draws the slag layer into a stream of metal being tapped.

Abstract: A flash smelting furnace which comprises a reaction shaft, a concentrate combustion device disposed at the top of the furnace shaft, a settler disposed with one end thereof connected to the lower part of the reaction shaft, an uptake disposed as connected to the other end of the settler and at least one lance pipe extending through the ceiling of the settler between the reaction shaft and the uptake and adapted to blow at least powdery raw materials and a reaction gas into the melt inside the settler.

Abstract: In a system for treating and managing hot aluminum dross, the dross is compacted and delivered by a pair of "squeeze" rolls in a continuous semi-solid sheet, readily broken up for further treatment or disposal. The rolls may be cooled or heated as required to condition the dross appropriately, for storage or immediate further treatment. Ribs on the rolls and/or a stepped "break" chute downstream of the rolls may be used to break the compacted dross into "patties" for convenient handling.

Abstract: A process is described for creating the flow properties to filtration residues from sodium production. These viscous-to-hard filter residues can be changed into a thin-fluid consistency by intensively agitating them under an inert gas for 2-6 hours at temperatures between 300.degree. and 600.degree. C.

Abstract: A porous ceramic structure suitable for use as a filter for molten metal, in which a porous ceramic body having pores capable of passing a fluid therethrough is covered with a metal layer over the wall surface of the pores such that a fluid may flow through the pores while in contact with the metal layer. The filtering efficiency can be improved due to the increased wettability between the ceramic filter and the molten metal.

Abstract: A nozzle or nozzles for spraying cooling water are disposed at the lower end of a slag suction path. A cooling water down-flow passage is provided on the outer periphery of an inner tube which constitutes a slag suction path. A water sump is provided below the cooling water down-flow passage, the water sump being located lower than the each nozzle. A lower end opening of the cooling water down-flow passage is disposed lower than the each nozzle and is submerged in water in the water sump. The cooling water down-flow passage, except the lower end opening, is adapted to be closed up. When the cooling water down-flow passage is closed up, water in the passage is stopped by atmospheric pressure acting upon the surface of the water in the water sump, so that it is prevented from flowing down.

Abstract: Apparatus includes a chamber with an inner and outer sidewall wherein fluxing gas inlets are provided on the inner sidewall and a space is provided between the inner and outer sidewall with a heating element and an air space between the heating element and the inner sidewall for providing uniform heating of the inner sidewall.

Abstract: An apparatus for separating a gas from a liquid but truly suited for use in a zero gravity environment. The apparatus includes first and second closed vessels each of which are separated into a gas and liquid zone. The first vessel is separated by gas de-entrainment means and the second vessel by a plurality of elongated passageways for capillary containment of a body of liquid. The passageways provide the sole source of fluid communication between the gas and liquid zones. The gas zones of the first and second vessels are in fluid communication with one another as are the liquid zones of the first and second vessels.

Abstract: An improved slag sensor taphole nozzle assembly for a metallurgical vessel having electromagnetic coils protectively located in grooves in the nozzle sidewall, with the nozzle sidewall being (1) non-ferromagnetic and (2) having high electrical resistivity.

Abstract: A ceramic filter for filtering molten iron is disclosed. The ceramic filter is made from a high-melting ceramic material having an open-celled foam structure, a variable bulk density in different portions of the filter, and at least one afflux surface. In order to filter molten iron efficiently, the ratio of filter surface to filter volume should be in the range of about 0.0003 to 9 m.sup.2 /cm.sup.3, the specific filter resistance should be in the range of about 0.1 to 0.9 bar-cm at a flow rate of 5 m.sup.3 /hour, and the pressure loss .DELTA.p across the filter should depend on the specific resistance .rho., the filter length, and the surface area of the afflux plane F in accordance with the relationship: ##EQU1## A method for filtering molten iron using this ceramic filter is also disclosed. In this method, the ceramic filter is located near the point in the casting system where the molten iron has its greatest kinetic energy.

Abstract: A device for the separation of slag and its retention in a converter, ladle, or the like, consists of a closure commonly called a dart, adapted to be placed either manually or automatically in the tap hole of the converter or ladle during tapping of molten metal therefrom. The device may have smooth exterior surfaces or may include configurations enabling it to substantially close the tap hole and impart a swirling motion to the molten metal and slag therein. The device may be formed of material having a specific gravity lower than that of the metal in the converter or ladle, but higher than that of the slag thereon or alternately having a specific gravity higher than that of the metal to facilitate manual placement of the device in the tap hole.

Abstract: The present invention relates to a technique for forming silicon carbide coated porous filters for use in filtering molten metal, especially copper and copper alloy melts. The technique comprises preparing a silicon carbide containing slurry having a viscosity in the range of about 1 to about 50, preferably from about 5 to about 30, centipoise and impregnating a rigid porous substrate material with the slurry. In a preferred embodiment, the slurry contains mono-aluminum phosphate as a binding agent, ethylene glycol as a wetting agent, powdered silicon carbide having a maximum settling rate of about 0.1 mm./min. and the balance essentially water. After draining of the excess slurry, the coated substrate material is heated to substantially prevent foaming of the coating during firing and fired to bond the silicon carbide coating to the substrate material.

Abstract: A molten metal pouring cup is provided communicating with a transfer means for transferring molten metal from the pouring cup to a casting station. Vent means is provided on the pouring cup at the interface between the pouring cup and the transfer means to permit release of entrapped gas downstream of the pouring cup.

Abstract: A monolithic refractory honeycomb filter of zircon or zircon plus an oxide additive is useful to remove impurities from molten metal, particularly from molten steel. The filter has a frontal contact surface containing the openings of a plurality of through-and-through cells for passage of the molten metal. Impurities adhere to the frontal contact surface of the filter and to the cell walls themselves.

Abstract: A molten metals filter apparatus having a hollow strainer, including an inlet port and a plurality of slot apertures having a uniform width for selectively restraining particulant impurities in molten metals.

Abstract: Improved filtration apparatus including a filter chamber having a metal inlet and a metal outlet defining a molten metal flow path therebetween and a filtration assembly engageable therewith disposed between the inlet and the outlet.

Abstract: The invention provides dross treatment apparatus comprising a drum rotatable about a horizontal axis with means to feed dross to the inside of the drum where it is cooled and broken by tumbling and then removed from the other end of the drum for separation and treatment. The invention also provides efficient delivery apparatus for introducing the dross to the apparatus.

Abstract: Installation according to the invention comprising a desilication and dephosphorization stage (A), followed by a decarburization stage and in which the pig iron to be pre-smelted is intended to form a bath whose free surface is maintained at a predetermined level (N.sub.1).The dephosphorization comprises a reactor (1) comprising means (5, 6, 8) respectively for introducing the pig iron to be pre-smelted, for adding desilication and dephosphorization agents, and for creating an oxidizing atmosphere, as well as rabbling means (9). It also comprises a decanter (2) separated from the reactor (1) by a partition (3) having an opening (4) below the level (N.sub.1) and whose upper end is above the latter. The decanter comprises an immersed outlet opening (10) connected to the decarburization stage and an overflow (12) for evacuating the slag. The slag formed in the reactor (1) flows out in the decanter (2), overflows above the partition (3), and moves toward the overflow (12) which evacuated it.

Abstract: A vortex inhibitor for use in tundishes, ladles, or metal making furnaces prevents the contamination of high quality molten steel by the slag layer which rides atop the surface of molten metal within such receptacles comprises a tapered polygonal body of castable refractory material whose specific gravity is less than the specific gravity of the molten metal but greater than the specific gravity of the slag. The refractory body is buoyantly supported at the interface of the layer of slag and the molten metal and includes a weighted apex so that the apex depends toward nozzle opening within receptacle. Thus, the body centers itself within the swirl of fluid generated during discharge of the fluid through the nozzle, and the inertia of the body substantially deenergizes the vortex so as to avoid formation of a suction funnel which typically draws the slag layer into and through the nozzle with the molten metal below the previously known critical level within the receptacle.

Abstract: There is disclosed a process and apparatus for recovering metallic uranium from scrap containing metallic uranium by introducing such metallic uranium scrap into a bath containing, in molten form, at least one member selected from the group consisting of BaF.sub.2, CaF.sub.2, MgF.sub.2, LiF, YF.sub.3, trifluorides of lanthanides and mixtures thereof, preferably with such member constituting at least 75 mole percent of the bath at a temperature above the melting point or uranium and under an inert atmosphere and casting the purified molten metallic uranium. The bath of molten salt preferably includes means for improving contact between the molten metallic uranium scrap and the molten salt during passage of the molten uranium through the bath of molten salt.

Abstract: High purity alumina filters suitable for relatively high temperature molten metal filtering applications are prepared by providing a composition comprising fine grain reactive alumina and a burn out material in amounts sufficient to increase the porosity of the resulting filter structure, the composition being free of grain growth inhibitors in amounts sufficient to inhibit growth of the alumina grains during firing; forming the composition into a honeycomb structure by suitable means; and firing the structure beyond the temperature providing maximum densification of the reactive alumina employed whereby grain growth is fostered. The honeycomb structure is fired sufficiently long for significant growth of the particles (from sizes less than about 5 microns to sizes between 10 and 20 microns) and for the creation of wide grain boundaries between the resulting grains which further act as crack arrestors. A preferred composition includes 19 parts by weight reactive alumina, at least 99.5% pure Al.sub.2 O.sub.

Abstract: An apparatus for producing low cost, high purity solar grade Si wherein a reduction reaction, preferably the reduction of SiF.sub.4, by an alkali metal (Na preferred) is carried out inside a reaction chamber. The chamber wall and bottom surfaces are formed of graphite and configured with drainage channels so as to facilitate the continuous separation of the products of reaction (Si and NaF) and removal of the molten salt by discharging the salt through one or more ports at the bottom of the reaction chamber. Such process is especially useful where it is desirable to discharge the reaction salt products from the reactor and retain silicon within the chamber for later removal.

Abstract: The present invention relates to a process and apparatus for the recovery of liquid aluminium by compression of hot dross.The process comprises placing the dross in a die up to a height which depends on the diameter of said die and which is lower at the center than at the periphery of the die, and then applying to the dross a punch which is moved downwardly at a speed which is lower in proportion to a lower level of concentration of liquid aluminium in the dross.The apparatus comprises a cylindrical die (10) provided with an insert member at each of its ends. The die rests on a base (3) which has an annular groove (4) on its upper face; the lower insert member (7) is of a diameter that is at least equal to the inside diameter of the groove and in any case less than the outside diameter and has a continuous upper face of conical shape; the space (16) between the wall surface of said insert member and the internal wall surface of the die is of a constant width and is disposed facing the groove.

Abstract: A charge channel opens into a primary melting chamber and comprises a substantially vertically extending first section and a second section which follows the first section and opens substantially tangentially into a cylindrically shaped bottom portion of the primary melting chamber. The charge channel is charged with melting stock by means of a funnel-shaped melting stock infeed. A jet of molten metal is fed into the first section by passage means comprising a pump and a conduit. The jet of molten metal is mixed in this first section with the melting stock which is infed into and passed through the first section in a free-falling movement. The melting stock is enclosed and entrained by the jet of molten metal which is tangentially injected into the melt-containing bottom portion of the primary melting chamber. A turbulent flow is thereby generated in the primary melting chamber and keeps the melting stock in motion during finish melting.

Abstract: The molten metal transfer crucible of the present invention filters molten metal during transfer of the molten metal to a receptacle such as a mold. The molten metal transfer crucible of the present invention is fitted with an external removable filter blade. The removable filter blade contains a filter element and is positioned with respect to an inlet in the transfer crucible such that molten metal is filtered by passing through the filter element contained in the blade while the crucible is being filled with molten metal. During operation molten metal can be intermittently back-flushed through the filter element contained in the blade. Back-flushing molten metal through the filter element extends the life of the filter element, and thereby increases the hours the transfer crucible may be operated between blade changes.

Abstract: A power driven press for recovering aluminum from aluminum dross is disclosed. The press has a receptacle for containing dross. The receptacle has at least one inclined sidewall and at least one passageway extending through its bottom. The passageway is sized and configured to permit the passage of free aluminum but inhibit the passage of a network of solid particles contained within the dross. Ram means for mechanically compacting the dross is also provided. The ram means applies a compressive force on the dross towards the inclined sidewall of the receptacle to force coalescence and separate a substantial portion of the free aluminum from the dross and pass it through the passageway provided in the receptacle's bottom. The ram means is provided with a ramming surface which faces the inclined sidewall surface of the receptacle. The ramming surface is inclined at an angle which is slightly less than that of the sidewall surface.

Abstract: An improved mechanism for recovery of metal, particularly aluminum, from metal bearing dross utilizes a trough for collection of the dross. A wedge member compresses the dross in the trough. In this manner, metal is decanted from the compressed dross and flows through slots in the bottom or passages in the walls of the trough for collection in a pan, or becomes concentrated at the edges or walls of dross. The trough and wedge members also serve to cool the dross material thereby diminishing metal loss due to thermite reaction.

Abstract: A steelmaking process and an article of manufacture for use therein, comprising the addition to the steelmaking vessel or caster tundish prior to the tapping of the finished steel of a heat-stable material having a density such that said material floats substantially at the interface between the slag and steel, said material being in the physical form of at least one annular disc. The heat-stable material may also be added to the vessel in the physical form of at least one discrete piece in addition to the annular disc.

Abstract: Molten slag is poured onto the upper surface of an elongated conveyor member. The surface of the conveyor member is cooled while maintaining it free from contact with liquids. Preferably, this is accomplished by way of a water cooled pan connected to the lower surface of the member. Reciprocal lengthwise motion is imparted to the conveyor member to transport the slag over the cooled surface until the slag is solidified and broken into pieces.

Abstract: An apparatus and method for filtering molten metal is disclosed. The apparatus includes a filtering vessel, a portion of which is a porous filter material. Attached to the rim of the filtering vessel is a shock resistant ring. The filtering vessel is positioned such that the porous filter material is submerged in the molten metal, and the rim is held above the surface of the molten metal by a brace which is attached to a fixed bracket.The molten metal is filtered by seeping through the porous filter material into the filtering vessel. The filtered molten metal is extracted from the filtering vessel.

Abstract: A method of and system for removing silicon from a high temperature liquid sodium coolant system for a nuclear reactor. The sodium is cooled to a temperature below the silicon saturation temperature and retained at such reduced temperature while inducing high turbulence into the sodium flow for promoting precipitation of silicon compounds and ultimate separation of silicon compound particles from the liquid sodium.