Patent ID: 7368076

Claim:
A method for producing a silicon nitride filter, which comprises heat-treating in nitrogen a green body comprising from 60 to 95 mass % of metal silicon particles having an average particle diameter of from 10 to 75 μm, wherein particles having particle diameters of from 5 to 100 μm are at least 70 mass % in the entire metal silicon particles, and from 5 to 40 mass % of a pore-forming agent, to convert metal silicon substantially to silicon nitride filter, wherein the green body comprises an inorganic acid salt, which is a nitrate, a chloride or a sulfate, wherein the inorganic salt comprises at least one metal element selected from the group consisting of Mg, Ca, Fe, and Cu, and wherein the inorganic acid salt is added in an amount of from 0.1 to 3 parts by mass as a metal element, per 100 parts by mass of the amount of the metal silicon particles.