Abstract: This invention concerns a weighing device to measure the weight of a sample of powder supplied by a suitable feed-mechanism.This weighing device comprises at least one sample-holder vessel and a taring vessel, connected to a transfer mechanism which moves the sample-holder vessel from a filling position where it is directly under the feed-mechanism, to receive the sample, to an emptying position, and which also sets the taring vessel and the vessel containing the sample on a weighing mechanism in turn, to measure their weight.The invention concerns this weighing device and an installation comprising such a device, used in particular for volumetric analysis of a sample of powder, such as raw material for cement-making.

Abstract: A binder for producing mortars or micro-concretes containing, by weight, 87% CPA 400 or CPA 500 cement, 13 to 19% aluminous cement and 0.1 to 1.0% of an organic agent. The mortars and micro-concretes prepared by means of said binder are adapted to spraying, in the moist state, or trowelling onto vertical, inclined or horizontal supports without any particular precautionary measure.

Abstract: This invention concerns a high-alumina refractory cement, which contains, in addition to ingredients adapted to form a hydraulic bond, and standard secondary ingredients, one or more ingredients adapted to form a phosphatic chemical bond.The invention concerns a high-alumina refractory cement and the process used to prepare it.

Abstract: The object of the present invention is a plaster obtained from phosphogypsum and its process of obtention. The plaster according to the invention contains phosphatic impurities which are fundamentally in the form of brushite and monetite of the formula CaHPO.sub.4, which corresponds in infra-red spectrometry to the appearance of a peak characteristic of this formula, said plaster having a normal setting time.

Abstract: A process of preparing a refractory hydraulic binder containing calcium aluminates, wherein45 to 65% clinker containing 45 to 72% CA phase, the balance being almost exclusively constituted by CA.sub.2 phase, and55 to 35% aluminaAre mixed in the presence of additives, all of the above-mentioned ingredients being ground.

Abstract: The present invention relates to an improvement in the process of U.S. Pat. No. 4,002,484, making it possible to obtain ettringite in fiber form.According to the invention, the process is carried out in the same way as in U.S. Pat. No. 4,002,484 but with enough water to assure having a suspension containing a maximum of 25% dry matter at the end of the reaction, and in subjecting said suspension to moderate stirring of 1 to 5 times the force necessary to maintain a homogeneous suspension.Application to the replacement of asbestos fibers, notably as a fire-proof product.

Abstract: A process includes hydrating between about 10.degree. and 100.degree. C, one of the synthesized anhydrous calcium aluminates prepared specially or stemming from the manufacture of hydraulic binders or of anhydrous calcium silicates, groundup to an average degree of fineness, with a quantity of water of such an order of magnitude that a paste is formed, having dry extracts between about 5 and 70% by weight; subjecting at least the large particles to a vigorous agitation during the hydration to form a suspension, drying the formed suspension to a dry powder and collecting the obtained dry powder.

Abstract: A hydrated mineral charge is manufactured by grinding a composition selected from the group consisting of calcium aluminates, aluminous cements, and Portland cements, to a powder having an average fineness of from about 3,000 to about 5,000 square centimeters per gram (Blaine's specific surface), hydrating the composition with water to form a paste at a temperature from about 10.degree. C to about 100.degree. C, and adding a sufficient quantity of a liquefying surface active agent to the paste so that its viscosity is less than about 5,000 cps, and so that the paste has a solid content from about 60 percent to about 80 percent by weight.

Abstract: Raw material for making cement is treated in an installation comprising a plurality of superimposed cyclones constituting a multi-stage exchanger wherein the solid raw material and gases issuing from a clinkerization furnace circulate counter-currently, and wherein at least a portion of the raw material issuing from the penultimate exchanger stage is injected into the gas current produced by the furnace. The raw material is injected in the form of a "curtain", or "screen", into an upstream section of the furnace. This novel method and the novel device for carrying out said method allow the building-up of deposits upstream of the furnace to be eliminated.

Abstract: The present invention relates to a process for obtaining low phosphorus steel by oxygen refining of liquid iron in the presence of a slag containing lime, alumina, silica and iron oxides wherein at the beginning of the operation is added to the liquid metal a charge obtained by granulation and calcination of a mixture of an hydraulic aluminous cement with lime and magnesia in order to obtain at the end of the operation a slag containing______________________________________ CaO 40 to 60 % SiO.sub.2 5 to 25 % MgO 2.5 to 15 % Al.sub.2 O.sub.3 5 to 25 % Iron oxides expressed as Fe.sub.2 O.sub.3 10 to 35 % P.sub.2 O.sub.5 0.5 to 10 % ______________________________________The process for obtaining steel by oxygen refining of iron known under the names of LD, LD-AC, Kaldo, OLP etc . . . which have made their appearance since a quarter of a century have seen their economic importance grow rapidly.

Abstract: A substantially stoichiometric mixture of calcic aluminate and calcium sulphate, as white as possible, formed at a temperature in the range of about 20.degree. to 90.degree. C, is hydrated simultaneously; water is added at least in stoichiometric proportions for the reaction and at a maximum in an amount such that after the reaction a product is obtained containing 5% (dry) ettringite and 95% (by weight) water, stoichiometry being defined, for example by the reactionCaO,Al.sub.2 O.sub.3 + (CaO, H.sub.2 O) + 3(CaSO.sub.4, 2H.sub.2 O) + 24 H.sub.2 O.fwdarw.(CaO).sub.3, Al.sub.2 O.sub.3, 3 CaSO.sub.4, 32 H.sub.2 O (ettringite)It is thus possible to obtain in an economical and very flexible manner, ettringite, or suspensions containing same, for all industrial uses, notably for paper-making.

Abstract: A compound of calcium carbonate and of hydrated tobermorites, constituted of 70 to 15% tobermorites, which may contain free hydrated silica in amounts to 0 to 15% in weight expressed in SiO.sub.2, and of 30 to 85% calcium carbonate. The process includes completely hydrating white Portland cements between about 5 and 100.degree. C to form a paste having a dry extract of 5 to 70% by weight until at least a decrease in the pH-value occurs.The compound is an industrial charge particularly for paper-making and paint-making industries.

Abstract: A composition is essentially of an ettringite base and contains from about 45 to 93% calcium trisulfoaluminate and from about 7 to about 55% tobermorites, of which from about 0 to 25% is hydrated silica, counted in the form of SiO.sub.2.

Abstract: A calcium-alumino composition formed by carbonating at a temperature between about 20.degree. to 100.degree. C, a hydrate of a water paste of an anhydrous calcium-alumino binder and an anhydrous calcium-silico binder formed at a temperature between about 5.degree. and 100.degree. C, said paste having a dry extract of about 5 to 70% by weight.

Abstract: A dead heap or pile is prepared on a circular surface in the form of a sector defined by two radii of the circular surface. With respect to the median plane of the dead heap, such heap has two slopes, each with an inclination equal to that at which particulate material is retrieved from piles (on semicircular plots) which are alternately laid, first on one side and then on the other side of the dead heap. Each such pile (on a semicircular plot) is laid directly against a slope of the dead heap and is retrieved from the edge of the pile which is most remote from the dead heap.