Provided is a manufacturing method with which it is possible to convert a mayenite-type compound to an electride, wherein a reducing agent is not required, reaction conditions include a temperature that is lower than that in the related art, and the reaction is performed more quickly in a simple manner, and, additionally, by requiring a lower amount of energy. Provided is a method for manufacturing an electride of mayenite-type compounds, the method being characterized in that a mayenite-type compound is converted to an electride by making a current directly flow through the mayenite-type compound by applying a voltage to the mayenite-type compound in a heating state.

Provided is a manufacturing method with which it is possible to convert a mayenite-type compound to an electride, wherein a reducing agent is not required, reaction conditions include a temperature that is lower than that in the related art, and the reaction is performed more quickly in a simple manner, and, additionally, by requiring a lower amount of energy. Provided is a method for manufacturing an electride of mayenite-type compounds, the method being characterized in that a mayenite-type compound is converted to an electride by making a current directly flow through the mayenite-type compound by applying a voltage to the mayenite-type compound in a heating state.

Prior art documents do not describe a method for modifying the surface of a calcium aluminate compound, much less describe a method for controlling the particle diameter of a calcium aluminate compound. The present invention provides a novel method for producing a calcium aluminate compound having a modified surface. The present invention provides: a method for producing a modified calcium aluminate compound characterized by irradiating a calcium aluminate compound dispersed in an organic dispersion medium with a femtosecond laser, thereby modifying the surface of the calcium aluminate compound; and a modified calcium aluminate compound characterized by being obtained by this method and having at least one of an OH group, a CO group, a CH group, and an NH group.

In a first step of a method for producing a transparent AlN sintered body, first, a formed body is prepared by forming a mixture obtained by mixing a sintering aid with an AlN raw-material powder containing a plate-like AlN powder whose plate surface is a c-plane and which has an aspect ratio of 3 or more. At this time, the mixture is formed such that the plate surface of the plate-like AlN powder is disposed along a surface of the formed body. In a second step, an oriented AlN sintered body is obtained by subjecting the formed body to hot-press sintering in a non-oxidizing atmosphere while applying a pressure to the surface of the formed body. In a third step, a transparent AlN sintered body is obtained by sintering the oriented AlN sintered body at normal pressure in a non-oxidizing atmosphere to remove a component derived from the sintering aid.

A method for controlling the concentration of impurities in Bayer liquors, the method comprising the steps of adding an oxide and/or a hydroxide of a metal other than aluminium to a Bayer liquor with a desired TA; forming a layered double hydroxide; and incorporating at least one impurity in said layered double hydroxide, wherein the impurities are selected from the group comprising phosphorus, vanadium and silicon.

A method for controlling the concentration of impurities in Bayer liquors, the method comprising the steps of adding an oxide and/or a hydroxide of a metal other than aluminium to a Bayer liquor with a desired TA forming a layered double hydroxide; and incorporating at least one impurity in the layered double hydroxide, wherein the impurities are selected from the group comprising chloride, fluoride, sulfate and TOC.

The present invention relates to a method for obtaining calcium aluminates for metallurgical use from non-saline aluminum slags by means of reactive grinding and thermal treatment.

A method of preparation of semiconductor material. The method includes: adding an organic substance containing a benzene ring and dodecacalcium hepta-aluminate (12CaO.7Al.sub.2O.sub.3 or C12A7) to a test tube, and sealing the test tube; heating the test tube to a temperature of 200-300 C., and holding the temperature for 1 to 3 hours; and continuously heating the test tube to a temperature of 900-1300 C., and holding the temperature for 10-120 hours.

The present invention relates to the manufacture of a chemical reagent whose principal active constituent comprises hydrated metastable forms of CAH.sub.10 and C.sub.2AH.sub.8 in aqueous suspension, and for use of the reagent within other processes where an aqueous suspension of precipitated calcium aluminate is required. The present invention further relates to the use of one or more particle segregation stages to assist the chemical reaction processes that are involved.

A process for preparing a composite material comprising an electride compound and an additive, said process comprising (i) providing a composition comprising the additive and a precursor compound of the electride compound, wherein the precursor compound comprises an oxidic compound of the garnet group, and wherein the additive has a boiling temperature which is higher than the melting temperature of the precursor compound; (ii) heating the composition provided in (i) under plasma forming conditions in a gas atmosphere to a temperature above the Httig temperature of the precursor compound and below the boiling temperature of the additive, obtaining the composite material.