Binder compositions for bonding particulate material

The present invention relates to binder compositions for bonding particulate materials. The invention has particular utility in the foundry industry, for forming bonded particulate articles, including foundry moulds and cores, and other refractory articles for use with hot molten metal, e.g. linings and feeder sleeves, including insulating, exothermic, and duplex (i.e. insulating and exothermic) sleeves. A bonded particulate material and a method for forming an bonded particulate material are defined. The material includes a particulate metal oxide that is capable of forming a metalate in the presence of an alkali. The metal oxide particles are typically dissolved in a solution of the alkali and then dried, such that an undissolved metal oxide core remains, surrounded by a metalate which is in turn bonded to metalate of adjacent particle and/or to a fill material.