APPARATUS FOR CAPTURING PLATINOIDS IN AMMONIA CATALYTIC OXIDATION PROCESS Russian patent published in 2000 - IPC

FIELD: industrial inorganic synthesis. SUBSTANCE: invention relates to nitric acid production and more specifically to precious metal gauzes that are used in the form of packets to capture platinum and rhodium volatilizing from catalyst surface during ammonia oxidation reaction. Capturing gauzes with mesh 400 to 1024 l/sq.cm are separated by high-temperature steel separation gauzes with mesh 49 to 70 l/sq.cm, which form no more than six beds, from which the first three contain no more than two capturing gauzes each and subsequent beds contain each one capturing gauze. Mesh of capturing gauzes in direction of reaction gas flow increases. First and latter separation gauzes are made with mesh 69-180 l/sq.cm. Material of capturing gauzes is composed of 4.0-8.0% copper, 0.3-1.0% tungsten, and palladium (the balance). If apparatus contains three beds, the first one contains no more than two lower-mesh capturing gauzes and the second and third beds contain each one higher-mesh capturing gauze. EFFECT: increased degree of capturing platinum, increased service time, and reduced consumption of precious metals. 2 cl, 1 tbl