Hoechst Aktiengesellschaft

Albert Braun

Georg Strauss

Willi Portz

Hans-Martin Delhey

Joachim Kandler

Hermann Schrodter

Wilhelm Portz

Klaus Komorniczyk

Hans-Dieter Thiel

Friedrich-Wilhelm Kampmann

An agent for desulfurizing molten metals, in particular molten iron, comprises a CaC.sub.2 /CaO crystal blend with a maximum of 62% by weight of CaC.sub.2, gas-evolving substances and 0 to 44% by weight of metallic magnesium as the components. For desulfurizing molten metals, in particular molten iron, using this agent, either the mixture comprising both the CaC.sub.2 /CaO crystal blend and gas-evolving substances, and the magnesium, are fluidized separately and the two fluidized products are combined immediately before they enter the melt, or the CaC.sub.2 /CaO crystal blend, gas-evolving substances and magnesium components are fluidized together and the fluidized product is introduced into the melt.

Agent and process for desulfurizing molten metals

Mixture for desulfurizing metal melts based on calcium carbide, calcium oxide, alkaline earth metal carbonates, aluminum oxide, chemically unbonded carbon and alkali metal carbonates, if any. The desulfurizing mixture contains 0.3-4.5 wgt % calcium fluoride as an additional constituent and is produced by grinding the individual constituents jointly in a mill over a period of 3-30 minutes.

Desulfurizing mixture for metal melts, process for making it, and

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 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.

Production of agent for desulfurizing crude iron and steel melts

Granular compositions containing pulverulent magnesium are made by blending the pulverulent magnesium ingredient with the desired other ingredient(s). To this end, a premix is formed by mixing, in a first stage, the pulverulent magnesium with the other ingredient(s) in a ratio by weight of 4:1 to 1:19; and intimately mixing this pre-mix, in a second stage, with further proportions of said other ingredient(s) giving a total ratio by weight of 1:799 to 1:19.

Production of granular compositions containing pulverulent magnesium

An iron melt is desulphurized. To this end, the irom melt is admixed with a powder mixture comprising metallic magnesium and at least one calcium compound, the latter being selected from calcium carbide, calcium oxide, calcium carbonate and dolomite, and the said calcium compound being used in the form of particles with a size of 0.06 to 3 mm, wherein the powder mixture contains 0.1 to 2.5 weight % of metallic magnesium in the form of particles having a size of 0.060 to 0.095 mm.

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Hurth, Germany

Albert Braun