METHOD FOR MANUFACTURE OF HIGH- POROUS METAL CARRIER FOR MONOLYTIC CATALYST UNITS

摘要

This method is used in the preparation of catalysts for the cleaning of waste gases from internal combustion engines and industrial waste gases from carbon oxide, hydrocarbons, nitric oxides and other toxic components. This method can be employed to produce highly porous carriers from nickel, avoiding the use of special ferritic steels with aluminium content, the application of technologically complex, labour consuming, and costly instrument treatment as well as the deposit of an aluminium layer of y-Al2O3. This method is based on a chemical reduction process whereby (following preliminary activation) a layer of nickel of 0.5 - 2.0 m is deposited onto an unfilled foamed polyurethane matrix with open porosity of more than 80%, the nickel being extracted from electrolyte composed of the following elements (g/l): nickel (II) chloride 20 - 25; sodium acetate 40 - 50; sodium citrate 30 - 35; ammonium chloride 15; sodium hypophosphate 15; for pH 4.5 - 5 and a temperature of 65 - 70 degrees C. The sub layer is then complemented (using the electrochemical method) with a layer of nickel (thickness over 15 um) extracted from an electrolyte composed of the following (g/l): nickel (II) sulphate 250 - 300; nickel (II) chloride 560 - 60; boric acid 25 - 35; 1.4 butin diole 0.2 ml/l and phthalimide 0.1 at cathode current density of 1 - 2 A/dm<2>. The matrix coated in nickel then undergoes thermal treatment for 60-70 minutes, in an atmosphere of pure hydrogen at a temperature of 1000 - 1100 degrees C. At the end of the process the matrix is removed.