INORGANIC BINDER

PURPOSE:To provide an inorganic binder showing hydraulic properties with a small amount of water, supplying a set material having heat resistance, exhibiting ceramic properties, by blending specific fine powder of calcium silicate containing a boron component with fine power of active silica. CONSTITUTION:Fine powder of calcium silicate comprising crystalline fine powder which has 1.3-3 basicity shown by the formula (M is alkali metal), contains 0.1-5wt.% calculated as B2O3 boron component and preferably further 3-10wt.% calculated as fluorine of a fluorine component and has 15,00-10,000m /g Blaine specific surface area of cooled molten material is prepared by a method of adding a boron-containing material and a fluorine- containing material to a molten material of steel manufacturing slag to modify the molten material. 100pts.wt. fine power of silicate calcium is blended with about 5-50pts.wt. fine powder of active silica (e.g., ferrosilicon dust) to give an organic binder suitable for building material, having both excellent cementing properties and ceramic properties.