Refractory product with a SiAiON matrix

A sintered refractory product consisting of: a granulate consisting of all the particles having a size larger than 100 [mu]m, or "grains", the granulate representing between 55% and 85% by mass of the product, the maximum size of the grains being smaller than 3.5 mm, and a matrix binding said grains and consisting of the particles having a size smaller than or equal to 100 [mu]m, or "fine particles", said matrix comprising at least one crystallised SiAlON phase of formula SixAlyOuNv, in which x is greater than or equal to 0, greater than 0.05, greater than 0.1 or greater than 0.2, and less than or equal to 1, less than or equal to 0.8 or less than or equal to 0.4; y is greater than 0, or greater than 0.1, greater than 0.3 or greater than 0.5, and less than or equal to 1; u is greater than or equal to 0, greater than 0.1 or greater than 0.2, and less than or equal to 1 or less than or equal to 0.7; v is greater than 0, greater than 0.1, greater than 0.2 or greater than 0.5, or greater than 0.7, and less than o