Abstract: The invention relates to a process for the purification of a polluted aqueous effluent to obtain an overall reduction in its chemical oxygen demand. The aqueous effluent is introduced into a reactor. Added to the reactor is a reagent comprising an agent supplying active alumina and lime. The reaction forms mineral sludge and an effluent. The mineral sludge and supernatant effluent are then extracted by decantation or filtration.

Abstract: The invention relates to a process for the purification of aqueous solutions polluted by nitrate ions. This process is characterised in that it consists in precipitating hydrated double or mixed calcium nitroaluminates, such as, in particular, hydrated calcium mononitroaluminate, by adding at least one agent supplying the element aluminium and at least one agent supplying the element calcium to the solutions to be treated, the overall mole ratio of the element aluminium to nitrate, Al/NO3, being superior to 1 and the overall mole ratio of calcium to nitrate, Ca/NO3, being superior to 2, and in that the precipitation reaction is performed with stirring and at a basic pH, preferably above 10.5.The process according to the invention is intende, in particular, to the treatment of polluted waters such as municipal waste water and factory effluents and to the treatment of liquid manure.

Abstract: The present invention concerns a method and a composition for accelerating the setting of Portland cement, shortening the migration phase of calcium ions into the liquid phase and complexing the lime of the Portland cement, whereby the said composition is essentially formed from the following constituents: a calcium aluminates- and trihydrated alumina-based material.

Abstract: A refractory cement with outstanding mechanical properties contains 10 to 30 parts by weight of C.sub.4 A.sub.3 S clinker and 70 to 90 parts by weight of an aluminous clinker including 30 to 75% CA. This cement may be prepared by either grinding said clinkers to a specified fineness and then mixing the same, or by grinding said clinkers simultaneously and jointly to said specified fineness. The novel double clinker cement allows concrete with considerably improved refractory and mechanical properties to be prepared, as compared to the corresponding products known up to now.

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: 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 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.