Abstract: The invention concerns a powdery product, of the type known as dry spray, for protecting centrifuge casting molds of cast iron pipes, comprising the usual components for this type of use, as well as an adjuvant for improving the flowability characteristics of said product when it is being deposited and make them less dependent on its physical or physico-chemical characteristics. Said adjuvant can be in particular silicone oil, potassium siliconate or micro-silica of density less than 0.1 g/cm3, as well as a mixture in any proportions of one or more of those.

Abstract: A powder product for the protection of centrifugal casting molds for cast iron pipes includes an inoculating metal alloy and possibly mineral powders, and a strongly reducing metal that is volatile at the temperature of the liquid cast iron. The use of products according to the invention prevents accumulation of dirt on molds and improves the surface condition of the cast iron pipes.

Abstract: The invention relates to an inoculant mixture for the treatment of molten cast iron, comprising 5 to 75% by weight of a ferro-silicon alloy of type A where Si/Fe>2, containing 0.005 to 3% by weight of rare earths, 0.005 to 3% bismuth, lead and/or antimony and less than 3% calcium, with a ratio (Bi+Pb+Sb)/TR of between 0.9 and 2.2 and 25 to 95% of at least one alloy of type B, based on silicon or ferro-silicon such that Si/Fe>2, containing calcium to a level such that the total amount of calcium in the mixture is from 0.3 to 3%. The above mixtures have a good granulometric stability over time and provide an efficient inoculation of cast pieces, in particular of thin pieces.

Abstract: The invention relates to a powder product for protecting centrifugal casting molds of cast iron pipes, dry-projected onto a first wet-spray layer, comprising constituents common to dry-spray products with exception of CaSi alloys, as well as a wet-spray additive serving to ensure the adhesion to the pipe, during its removal from the mold, initially applied to the permanent mold. Said additive can be an alkali carbonate or alkali silicate, for example, sodium silicate in which the ratio of the wt. % of SiO2 to that of Na2O varies from 1 to 3, or anhydrous sodium metasilicate as well as a mixture consisting of one or more thereof in any proportions.

Abstract: The invention concerns a powdery product, of the type known as dry spray, for protecting centrifuge casting molds of cast iron pipes, comprising the usual components for this type of use, as well as an adjuvant for improving the flowability characteristics of said product when it is being deposited and make them less dependent on its physical or physico-chemical characteristics. Said adjuvant can be in particular silicone oil, potassium siliconate or microsilica of density less than 0.1, as well as a mixture in any proportions of one or more of those.

Abstract: A method for inoculating molten iron. The method comprises passing the molten iron through a filter assembly at an approach velocity of about 1 to about 60 cm/sec. The filter assembly comprises a filter element and an inoculation pellet in contact with the filter element. The pellet has an inoculant dissolution rate of at least 1 mg/sec. to no more than 320 mg/sec. and comprises about 40-99.9%, by weight, carrier comprising ferrosilicon. The pellet further comprises about 0.1-60%, by weight, at least one inoculating agent selected from a group consisting of cerium, strontium, zirconium, calcium, manganese, barium, bismuth, magnesium, titanium and aluminum or from rare earths.

Abstract: A pellet, intended for the late inoculation of cast irons, obtained by agglomeration of a powdered inoculant, characterised in that the mass proportion of the granulometric fraction 50-250 microns of the powdered inoculant of which the pellet is constituted is comprised between 35 and 60%, and the mass proportion of the granulometric fraction below 50 microns is lower than 25%.

Abstract: A metallurgical-grade silicon for use in alkyl or aryl halosilane synthesis, and having a structure consisting of primary silicon crystals and intermetallic compounds, particularly of silicon, aluminum and calcium, wherein at least 90% of the primary silicon crystals have an aluminum content of 50-1000 ppm. This structure substantially enhances the reactivity of the silicon in the synthesis reaction.

Abstract: Powder product for the protection of molds for centrifugal casting of cast iron tubes, and a method for its production. The powder contains a mixture of a silicon-based inoculating agent and a mineral powder, the silicon-based inoculating product comprising waste masses from synthesis of alkyl- or aryl- halosilanes, from which tin and optionally copper has been removed. The mineral powder may contain at least one material selected from the group consisting of carbon and a fluoride.

Abstract: A process for the preparation of active silicon powder for use in the Rochow reaction consisting of grinding metallurgical silicon to a particle size less than 350 .mu.m in the presence of at least one catalyst and/or reaction promoter, in order to deposit this (these) element(s) on the grain surface, and an active silicon powder with a particle size of less than 350 .mu.m, with 0.01 to 0.1 g/m.sup.2 of copper, and/or 0.003 to 0.03 g/m.sup.2 of tin, and/or 0.003 to 0.03 g/m.sup.2 of phosphorus on the surface of the grains, for use in the Rochow reaction. The reactivity and selectivity of the powder are improved, and it has a shorter reaction incubation time.

Abstract: A metallurgical silicon or ferrosilicon in the form of granulates having an average size of less than 10 mm and in which the total oxygen concentration is less than 0.05% by weight, and a process for manufacture of this silicon or ferrosilicon consisting of a carbothermal reduction of silica in an electric oven, chlorine-based refining of the liquid metal, and granulation of the refined liquid metal in water under an inert atmosphere. The silicon may be used for silicone manufacture or as a constituent of an aluminum alloy, and the ferrosilicon, as a steel additive used to obtain magnetic sheet metals for electrical construction.

Abstract: A ferrosilicon-based ferroalloy for inoculation of spherulitic graphite irons containing (by weight) from 0.005% to 3% rare earths, 0.005% to 3% bismuth, lead and/or antimony, and 0.3% to 3% calcium, and is characterized by the fact that Si/Fe>2 and contains from 0.3 to 3% magnesium. The ferroalloy exhibits improved granulometric stability during storage.

Abstract: A metallurgical silicon is disclosed which contains substantially from 30 to 180 ppm of phosphorus comprised of a crystalline phase of primary silicon having a dissolved phosphorus content between 30 and 150 parts per million and intermetal phases whose global ratio is between 0.5 and 2%, wherein among the intermediary phases, the phase Si.sub.2 Al.sub.2 Ca does not exceed 0.3% of the total of the metallurgical silicon mass. The metallurgical silcon is used for the synthesis of alkyl or aryl halogenosilanes useful for the preparation of silicones.

Abstract: A device for mounting a self-baking composite electrode for an electric arc furnace, which includes a hollow metallic shell, a central column of graphite or pre-baked carbon comprising a plurality of elements fitted together by means of nipples. A carbonaceous paste is disposed between the shell and the column. The column is suspended from a support which is movable in a vertical direction with respect to the shell, along a length which is greater than the length of each of the elements. The invention is particularly relevant to furnaces for the production of silicon by carbothermic means.

Abstract: A method and an apparatus for condensing to the liquid state vapors of a metal having a melting point of between 500.degree. and 850.degree. C. in a double envelope container. The pressures between the two faces of the inner envelope of the container are adjusted to be in equilibrium, and the outer face of the inner envelope is cooled in such a way as to keep the inner face temperature substantially constant in the vicinity of the solidification temperature of the metal. The invention is applicable in particular to condensing magnesium vapors.

Abstract: The invention relates to a silicon alloy intended for the production of alkyl or aryl halogenosilanes using the Rochow reaction, comprising, in percent by weight:0.05<Al<0.300.01<Ca<0.300.02<O.sub.2 <0.200.10<Fe<0.500.01<Ti<0.15x<Cu<2+xwhere x=3.2 (% Ca)+9.4 (% Al) the remainder being silicon. The alloy according to the invention makes it possible to improve the reactivity and the selectivity of the reaction.

Abstract: A process for recovery of magnesium from magnesium alloy waste by charging an electric furnace with a flux including at least one salt, the flux being inert with respect to magnesium and having a melting point <1000.degree. C. The flux is raised by the Joule effect at a reduced pressure to a temperature of 900.degree. to 1100.degree. C. to produce a bath having a density higher than that of magnesium, a vapor pressure <0.1 torr and an electrical resistivity of between 1 and 10 milliohm.m. The magnesium alloy waste is introduced in the bath, and magnesium and any other elements in the waste which are more volatile than magnesium are recovered from a vapor phase above the bath. Any elements in the waste which are less volatile than magnesium are recovered from a molten phase in a bottom portion of the furnace.

Abstract: Apparatus for the late introduction of a particulate alloy when casting liquid metal, disposed between a casting ladle or an apparatus for the automatic feed of said metal and a series of moulds to be filled, characterised in that it comprises a jet of liquid metal of sufficient thickness, which is confined and in motion in a mixing chamber, for example a vortex, and a non-immersed introduction means (8) for the introduction of particles of alloy, imparting to said particles a speed and an energy sufficient for them to penetrate deeply into the interior of the liquid metal in the zone (4) of sufficient thickness, said zone being disposed in the vicinity of a casting orifice (5).

Abstract: Silicon or silicon alloy exhibiting low surface oxidation as a result of a surface silica layer of less than 2 nm, and production processes by means of grinding under a minimally-reactive atmosphere in the presence of an oil or by atomization in a vacuum or in a minimally-reactive gas under reduced pressure.

Abstract: A method of producing heavy metal carbides of high specific surface area characterised in that a compound in the gazeous state of said heavy metal is caused to react with reactive carbon having a specific surface area at least equal to 200 m.sup.2.g.sup.-1 at a temperature comprised between 900.degree. and 1400.degree. C., and thus obtained carbides.