Bayer Aktiengesellschaft

Hermann Rohe

Hans Guth

Bernhard Spreckelmeyer

Werner Ludovici

Alex Burger

Werner Schabacher

In the production of activated carbon by passing a preheated gaseous activation medium through a zone containing a bed of carbon-containing material while indirectly heating to maintain a temperature of about 500.degree. to 1100.degree. C., supplying carbon-containing material to the bed, and removing activated carbon from the bed, the improvement which comprises introducing the activation medium and the carbon-containing material co-current near the bottom of the zone at a rate such that gaseous products are formed in a quantity sufficient to maintain in the zone a lower static layer and an upper fluidized layer in particular proportions, the rate of supply of the carbon-containing material and withdrawal of activated carbon being related so as to convert about 30 to 55% by weight of the carbon-containing material to gaseous products. The average residence of the carbon-containing material is from about 0.2 to 6, preferably 1 to 4, hours. A suitable apparatus for carrying out the process is described.

Production of activated carbon in a reactor having a lower static layer

In the production of hydrofluoric acid and calcium sulfate by subjecting sulfuric acid and fluorspar to a partial preliminary reaction in a preliminary reaction zone and the reaction is completed in an after-reaction zone at a temperature from about 100.degree. to 500.degree. C, the improvement which comprises effecting the preliminary reaction by circulating preliminary reaction product through said preliminary reaction zone, adding to the circulating preliminary reaction product at spaced locations in the preliminary reaction zone sulfuric acid preheated to a temperature of about 80.degree. to 200.degree. C and fluorspar preheated to a temperature of about 400.degree. to 800.degree. C, removing from said preliminary reaction zone gaseous hydrofluoric acid and a substantially dry mixture of calcium sulfate, unreacted sulfuric acid and fluorspar, and passing said dry mixture of calcium sulfate, unreacted sulfuric acid and fluorspar to said after-reaction zone. Only some of the necessary sulfuric acid may be supplied to the preliminary reaction zone and the balance supplied to the after-reaction zone. Heating of the preliminary reaction zone can be external or materials can be added which will react exothermically, e.g. SO.sub.3 to react with water in the system, CaO to react with sulfuric acid. A suitable apparatus is provided, comprising two parallel troughs connected at their ends by overflows and with oppositely rotating screws to circulate the contents. Means are provided for introducing reactants at spaced locations and for removing a mixture of product plus unreacted starting materials.

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Leverkusen, Germany

Hermann Rohe