| 摘要 |
PURPOSE:To manufacture the metallic Cr having extremely high purity at low cost, at the time of manufacturing metallic Cr by a thermit process, by adding specified amounts of powder of C and metals easy to sulfurize to a mixture of Cr2O3 powder and Al powder as a raw material, pulverizing the obtd. thermit coarse metallic Cr and heating it in a vacuum heating furnace. CONSTITUTION:A thermit raw material constituted of a mixture of Cr2O3 powder and Al powder as a reducing agent is ignited to cause a thermit reaction, by which metallic Cr is manufactured. Because impurities such as O2 and S remain in the obtd. metallic Cr, to the thermit mixed raw material, C for producing CO is added against residual O2 by 0.8 to 1.2 molar ratio to O2 as well as the powder of at least one kind among Ni, Cu, Sn, Mg, Hg, etc., for forming sulfide is added against residual S by 0.8 to 1.2 molar ratio to S, and they enter into solid soln. in the metallic Cr obtd. by the themit reaction. The thermit coarse metallic Cr is pulverized and is thereafter heated in a vacuum heating furnace to remove the included O2 and S respectively as CO and the sulfide of Ni, Cu, Sn, etc., by which the high purity metallic Cr contg. less impurities can be manufactured.
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