Lafarge Fondu International

Lafarge

Lafarge Sa

Alain Mathieu

Jean M Schmitt

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.

Method and composition for accelerating the setting of cements and

A refractory plaster containing semi-hydrated calcium sulphate, mineral fibres and a mineral filler material. This plaster has outstanding fire-retardant properties at temperatures of up to 1400.degree. C. and can be used as a refractory material, while being adapted to be used in a manner similar to that of a conventional plaster.

Refractory plaster

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.

Method of preparing a novel cement particularly suitable as a refractory

This material is an anorthite with an alumina skeleton of which the overall porosity is between 40 and 70% with a pore size such that the average diameter is between 0.75.mu. and 8.mu.. To obtain it, water is mixed with a mixture of aluminous and sillicoaluminous materials with at least 10% by weight of calcium sulphate, it is dried and calcined at 1000.degree. to 1400.degree. C. The starting materials are selected so that the final product essentially comprises CaO, SiO.sub.2 and Al.sub.2 O.sub.3 with, by an SiO.sub.2 /Al.sub.2 O.sub.3 weight ratio less than 2 and a CaO/Al.sub.2 O.sub.3 weight ratio less than 1. A preferred composition corresponds to point D of the diagram. Application to replace plaster in the manufacture of moulds for the sanitary industry.

Microporous material especially for use in the ceramic industry

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.

High alumina refractory cement and a process for producing the same

A process of preparing a refractory hydraulic binder containing calcium aluminates, wherein

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Montelimar, France

Alain Mathieu