Metallgesellschaft Aktiengesellschaft

Bayer Aktiengesellschaft

Georg Daradimos

Martin Hirsch

Lothar Reh

Wolfram Schnabel

Harry Serbent

Hugo Grimm

Rudolf Gerken

Karl-Heinz Dorr

Hans Beisswenger

Ludolf Plass

Hermann Wieschen

Georg Schmidt

Christoph Mucke

Jorg Thomas

Sponge iron is produced by a direct reduction of iron oxide containing materials in a rotary kiln, the material discharged from the rotary kiln is separated into sponge iron and material which contains surplus carbon, the carbon-containing material is burnt in a fluidized bed reactor containing a circulating fluidized bed, and the heat generated by the combustion is recovered and utilized to produce electric power. To ensure a utilization of the surplus energies of the rotary kiln process and to minimize the contents of SO.sub.2, NO.sub.X, and CaS, the dust-containing exhaust gas from the rotary kiln is supplied to the fluidized bed reactor and is afterburnt therein, at least a major part of all oxygen-containing gases supplied to the fluidized bed reactor is supplied as a fluidizing gas to the lower portion of the fluidized bed reactor, the combustion of the combustible constituents is effected with an over-stoichiometric oxygen content, and the solids entrained by the gases discharged from the fluidized bed reactor are recycled to the fluidized bed reactor in such a manner that the weight of solids circulated per hour is at least 5 times the weight of the solids contained in the fluidized bed reactor.

Process for generating heat and producing sponge iron

In a process of simultaneously producing fuel gas and process heat from carbonaceous materials wherein the carbonaceous materials are gasified in a first fluidized bed stage and the combustible constituents left after the gasification are subsequently burnt in a second fluidized bed stage the throughput rate and the flexibility are increased in that the gasification is carried out at a pressure of up to 5 bars and a temperature of 800.degree. to 1100.degree. C. by a treatment with oxygen-containing gases in the presence of steam in a circulating fluidized bed and 40 to 80% of the carbon contained in the starting material are thus reacted. Sulfur compounds are removed from the resulting gas in a fluidized state at a temperature in the range from 800.degree. to 1000.degree. C. and the gas is then cooled and subjected to dust collection. The gasification residue together with the by-products which have become available in the purification of the gas, such as laden desulfurizing agent, dust and aqueous condensate, are fed to another circulating fluidized bed and the remaining combustible constituents are burnt there with an oxygen excess of 5 to 40%.

Method of producing fuel gas and process heat fron carbonaceous materials

The invention provides a process for thermally decomposing salts, containing mainly ferrous sulfate wherein said feed material is contacted in a single suspension-type exchanger with exhaust gases formed by reaction of the oxygen-containing gases in the fluidized bed reactor, the fluidizing gas and at least a partial stream of the secondary gas stream are heated by an indirect heat exchange in a fuel-heated heat exchanger, and the quantity of oxygen introduced via which consists of the fluidizing gas and the secondary gas, is controlled in dependence on the quantity of fuel in order to receive an exhaust gas from the suspension-type exchanger with a free oxygen content of 1-6% by volume and a temperature of 300.degree.-450.degree. C.

Process for obtaining metal oxide and SO.sub.2 -containing gases

A process for the recovery of sulfuric acid from waste sulfuric acid containing iron sulfate and from solid iron sulfate of high water content of crystallization which consists essentially of: A. concentrating waste sulfuric acid to an acid concentration of 25-55 weight percent, based upon the suspension, by removing water therefrom; B. mixing the concentrated acid of Step A with recycled concentrated sulfuric acid obtained from Step E to form a resultant acid mixture of acid concentration of 30-65 weight percent, based upon the suspension; C. adding said solid iron sulfate of high water content of crystallization to the acid mixture of Step B thereby obtaining iron sulfate of low water content of crystallization; D. separating the iron sulfate of low water content from the resultant sulfuric acid solution of Step C; E. concentrating the separated sulfuric acid solution of Step D to an acid concentration of 45-70 weight percent, based on salt-free acid, and recycling at least a portion thereof to Step B; and F. thermally decomposing the iron sulfate from Step D to produce iron oxide and sulfur dioxide.

Process for producing sulfuric acid from waste acid and iron sulfate

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Maintal, Germany

Georg Daradimos