Hoechst Aktiengesellschaft

Willi Portz

Georg Strauss

Albert Braun

Hans-Martin Delhey

Erhard Wolfrum

Hans-Joachim Kersting

The disclosure relates to a process for the manufacture of desulfurizing agents containing 1-6 weight % chemically combined water, based on calcium oxide and carbon-containing calcium carbide, for crude iron and steel melts. More particularly, the disclosure provides for a molten mixture of calcium carbide and calcium oxide containing 20 to 80 weight % CaO to be made from lime and coke; for the mixture to be allowed to cool and solidify into a block; for the solidified block while it still has an average temperature of more than 400.degree. C. to be crushed to particles with a size of less than 150 mm; for the comminuted mixture, which still has a temperature of at least 400.degree. C. to be admixed with a quantity of calcium oxide necessary to establish in the resulting mixture a total content of CaO corresponding to the CaO content desired in the end product; and for the mixture to be gound while intensively mixing it with free carbon and carbonate in the presence of air or nitrogen with a moisture content of 5 to 20 g/m.sup.3 (at 1.013 bar and 273.15 K.) at temperatures below 100.degree. C. to particles with a size of less than 10 mm.

Process for making agents for desulfurizing crude iron or steel melts

The disclosure provides mixtures for the desulfurization of metal melts, especially steel and crude iron melts, based on CaC.sub.2 --CaO-crystal blends produced in the fused mass. More specifically, the mixtures contain free carbon and carbonate and have a portion of the CaO in the CaC.sub.2 --CaO-crystal blend hydrated to Ca(OH).sub.2. The disclosure also relates to a process for making the mixtures.

Desulfurization mixture and process for making it

The invention relates to a process for making calcium carbide by reacting an excess of coke with quicklime in the presence of oxygen in an oxygen-thermal furnace. To this end, the invention provides for precrushed coal to be used as starting material for coke and precrushed lime hydrate (Ca(OH).sub.2) or precrushed limestone (CaCO.sub.3) to be used as a starting material for quicklime. The precrushed materials are mixed and the resulting mixture is introduced into a drying zone and freed therein at 80.degree. to 120.degree. C. from adhering water. Next, the warm mixture coming from the drying zone, and air, are introduced into a calcining apparatus in which the coal constituent is coked and the lime constituent is simultaneously dehydrated or decarbonized, at temperatures of 900.degree. to 1400.degree. C. The thermally-pretreated mixture of starting materials with an inherent temperature of 900.degree. to 1000.degree. C. is then directly introduced into the oxygen-thermal furnace and reacted with oxygen to calcium carbide.

Production of calcium carbide

The present invention relates to a process for the manufacture of desulfurizing agents containing 1-6% by weight of chemically bonded water, based on calcium oxide-containing calcium carbide, for crude iron and steel melts. To this end, a molten mixture of calcium carbide and calcium oxide with a CaO content of 20 to 80% by weight is produced, which is allowed to solidify into a block. Next, the block which still has an average temperature of more than 400.degree. C., is rough-crushed to particles with a size of less than 150 mm and calcium oxide is added to the comminuted mixture, which still has a temperature of at least 400.degree. C., in accordance with the CaO content desired in the end product. The mixture is finally ground in the presence of air or nitrogen with a moisture content of from 5 to 20 g/m.sup.3 (at 1.013 bar and 273.15 K) at temperatures below 100.degree. C. to particles with a size of less than 10 mm.

Process for the manufacture of desulfurizing agents for crude iron or

The invention relates to agents for the desulfurization of metal melts, especially of steel and crude iron melts, based on mixtures of CaC.sub.2 /CaO crystals produced in the fused mass. A portion of the CaO in the crystal mixture is hydrated to form Ca(OH).sub.2. A process for the manufacture of these agents is also described.

Desulfurizing agent and process for its manufacture

The invention relates to the production of an agent for desulfurizing crude iron and steel melts, the desulfurizing agent being based on calcium carbide containing calcium oxide. To this end, a calcium carbide/calcium oxide/starting melt mixture with a CaO-content within the range 20 to 80 weight % is produced from lime and coke and allowed to solidify to a block. While the solidified block still has an average temperature of more than 400.degree. C., it is crushed to particulate material with a size of less than 150 mm. Next, the hot crushed material of at least 400.degree. C. is admixed with a quantity of calcium oxide necessary to have in the resulting mixture an overall content of CaO corresponding to that desired for the final product. The whole is thoroughly mixed and crushed with exclusion of moisture at temperatures higher than 100.degree. C. to particulate material with a size of less than 10 millimeters.

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Erftstadt, Germany

Willi Portz