Hoechst Aktiengesellschaft

Herbert Diskowski

Joachim Stendel

Hermann Niermann

Johannes Krause

Hans Ebert

Winfried Kern

Dietrich Mandelkow

Karl Rottgen

Hans Rabowsky

Heinz Stephan

Bernhard Schafgen

Phosphorus pentasulfide is made. To this end gaseous nitrogen is introduced into the pipes feeding a reactor with a phosphorus melt and sulfur melt and/or into the outlet pipe for the phosphorus pentasulfide melt, the nitrogen being admitted under a pressure lower than the static pressure exerted in the pipes by the quantity of melt upstream of the gas inlets.

Process for making phosphorus pentasulfide

The disclosure relates to a process for removing foreign components, especially zinc, from the product cycle during the production of yellow phosphorus inside and electrothermal furnace. To this end, the disclosure provides for molten ferrophosphorus and a calcium metasilicate slag and also a dust-containing gas mixture consisting essentially of carbon monoxide and phosphorus in vapor form to be taken from the furnace charged with phosphate pellets, coke and gravel. After electrostatic separation of the dust from the gas mixture, the dust is water-treated and made into a dust suspension. Crude phosphate is granulated on a granulating means using a mixture of dust suspension and binder which preferably is a clay suspension. The granulated material is calcined on a sintering device and made into phosphate pellets. A portion of the molten slag taken from the electrothermal furnace is allowed to solidify and the solidified slag is ground. The ground slag and at least a portion of dust suspension are granulated on a granulating means. The granulated slag and dust suspension are dried. It is possible for the dried granulated matter to be ground once again, to be granulated once again together with a further portion of dust suspension, and to be dried again. The dried and granulated matter is ultimately calcined and made into pellets.

Process for the electrothermal production of yellow phosphorus

The invention relates to a process for working up phosphorus-containing waste water by subjecting it to filtration with the use of a filter aid in a centrifugal filter. To this end, waste water with a temperature of at least 46.degree. C. and a pH-value within the range 0.5 to 4.0 is introduced into the centrifugal filter and fitrate coming from the centrifugal filter is introduced into a calming zone and separated therein within an average period of 10 to 60 minutes into yellow phosphorus and water containing 1 to 30 ppm of phosphorus. Water overflowing from the calming zone is treated with an oxidant and the waste water so freed from phosphorus is reacted with a neutralizing agent.

Process for working up waste water containing phosphorus

The invention provides carbon carriers of improved reactivity suitable for use in slag-forming electrothermal reduction processes. The improved carbon carriers contain 5 to 80 weight % of the particular slag formed in the reduction process. The invention also provides a process for making the carbon carriers.

Carbon carrier suitable for use in electrothermal reduction processes,

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Erftstadt, Germany

Herbert Diskowski