Patent GB-294975-A (GB)
Title: Contact sulphuric acid process
IPC: C01B17/79
Filed: 1928-01-23
Abstract: 294,975. Selden Co., (Assignees of Jaeger, A. 0.). Aug. 3, 1927, [Convention date]. Catalysts, preparation and treatment of. - A catalyst for oxidizing sulphur dioxide to trioxide comprises at least one catalytically active, non- siliceous base exchange body in which at least one catalytically active component is chemically combined in exchangeable or non-exchangeable form, with or without, the presence of stabilizers or stabilizer promoters chemically combined with the base exchange body or physically associated therewith. Vanadium is very effective as the active element. An active acid radical may be combined with the base exchange body to form a salt-like substance,. The base-exchange bodies may be produced (1) by precipitating an alkaline solution of an amphoteric metal hydroxide by means of a metallic salt solution; (2) by cautiously neutralizing with acid a solution of a simple or complex metallate of an amphoteric metal; (3) by neutralizing with alkali an acid or neutral solution of a salt of an amphoteric metal; (4) by the reaction between a neutral or acid salt particularly of an amphoteric metal and an alkali metal salt of an oxygen acid of a metal of the 5th or 6th group. They may also be obtained by fusion of metallic oxides, or hydroxides with alkali. The catalysts may be precipitated upon: or otherwise incorporated during or after formation with diluents, finely divided or massive carriers, other catalysts, &c. Suitable diluents are siliceous materials in general, and also inactive base.exchanging bodies of zeolite or non- siliceous type. The metallate-forming elements may be aluminium, chromium, zinc,. vanadium, beryllium, tin, palladium, platinum, titanium, zirconium, tungsten. lead, uranium, tantalum, boron, molybdenum. Instead of simple metallates, complex compounds with ammonia, cyanogen, &c. may be used. The metal salt components may be copper, silver, gold, beryllium, zinc, cadmium, aluminium, rare earths, titanium, zirconium, tin, lead, thorium, chromium, uranium, vanadium, manganese, iron, nickel, cobalt, platinum, palladium. The same metal may be present. as metal salt and as metallate in the same or a different, degree, of oxidation. Part or all of the alkali cations in the base-exchange bodies may be replaced by exchanging with other atoms or radicals. The bodies may also be converted into salt-like compounds by reaction with acid radicals, e.g. of the elements vanadium. tungsten, uranium, chromium, molybdenum. manganese, tantalum, titanium, bismuth, sulphur. chlorine, platinum, boron, or complex ions such as ferro- and ferricyanogen, sulpbocyanogen, &c. The presence in the cataolysts of alkali and alkaline earth metals is found to have a stabilizing effect on the catalytic action, and many of the catalytically inactive, amphoteric metal ingredients serve to promote this stabilizing action. Stabilizer promoters may also be present in the diluent. The Specification contains numerous examples of procedure, of which the following is typical : vanadium pentoxide is suspended in dilute sulphuric acid and reduced with sulphur dioxide to vanadyl sulphate. Part of this solution is treated with potassium hydroxide to produce potassium vanadite, which is mixed with sodium aluminate solution and with a diluent, e.g. a base-exchanging aluminium polysilicate. The remaining portion of the vanadyl sulphate solution is then added. The product is pressed, dried, broken into fragments, and sprayed with sulphuric acid to form a salt-like body or digested with copper sulphate solution to displace part of the alkali by copper. Specification 286,708 is referred to.