Bayer Aktiengesellschaft

Siegfried Gruhl

Klaus Holzer

Hans-Hermann Heins

Eberhard Zirngiebl

Martin Ullrich

Michael Bueb

Hanno Henkel

Horst Weber

Peter Danz

Werner Pusch

Siegbert Humberger

Goetz-Gerald Borger

Karl-Heinz Endlich

A carbon- and nitrogen-based catalyst consisting essentially of active carbon or active coke and comprising at least 90% by weight of graphite structures containing at least 10% of pores larger than 100 nm in diameter and having incorporated therein an isocyanate which forms C-N-ring structures, the percentage graphite content being at least 90% by weight. The catalayst is especially effective in the low temperature reduction of nitrogen oxides in waste gases.

Catalyst for the reduction of nitrogen oxides from waste gases and a

A carbon-based catalyst which has a carbon content of &gt;65% by weight and a content of substantially insoluble oxides of the metals Co, Fe, Ni, Cr, V, Mo, W, Cu, Mn and Ti of, in all, 0.1% by weight and a nitrogen content of 0.2 to 5% by weight. These catalysts are produced by a process wherein an organic material comprising unsaturated carbon-carbon bonds is pyrolyzed in a first step via the liquid phase stage, the product formed is size-reduced after cooling, mixed with substantially insoluble metal oxides and/or compounds forming substantially insoluble metal oxides together with binders and, optionally, water and the resulting mixture subjected to forming and heat treatment. The catalysts are useful in various gas-solid reactions more especially for the reductive destruction of nitrogen oxides in smoke gases.

Carbon-based catalyst useful in gas-solid reactions

A process for the reduction of nitrogen oxides contained in exhaust gases comprising reacting the gases with a reducing agent in the presence of a catalyst, the catalyst being based on carbon and having a carbon content greater than 65% by weight and containing 0.1 to 10% by weight of a sparingly soluble oxide of one or more metal selected from the group consisting of Co, Fe, Ni, Cr, V, Mo, W, Cu, Mn and Ti and having a nitrogen content of from 0.5 to 5% by weight, wherein the molar ratio of the reducing agent to the nitrogen oxide is 0.3 to 0.7.

Process for the reduction of nitrogen oxides from exhaust gases

In the production of annealed products such as inorganic pigments wherein pigment-forming starting materials are mixed, optionally with the addition of auxiliary substances, thereafter annealed, optionally ground, washed and then dried, the improvement which comprises adding water to the mixture of pigment-forming materials to form an aqueous suspension containing at least about 10% by weight of H.sub.2 O, and applying said suspension to the surface of a hearth which has been heated to at least about 500.degree.C, thereby to heat said materials and to effect annealing. Advantageously the hearth is a horizontal, flat ring rotating about its center and in the course of one rotation of the ring the applied material is heated to the temperature of formation of the desired annealed product, calcined and removed from the surface of the ring before the one rotation has been completed.

Production of annealed pigments

Growing community of inventors

Engelskirchen, Germany

Siegfried Gruhl