Abstract：The content of metallic iron in desulfurization slag has important guiding significance for its reuse, so the determination method of metallic iron in desulfurization slag has attracted much attention. During the direct determination of metallic iron in desulfurization slag by potassium dichromate titration after iodine-ethanol leaching, the presence of iodine-ethanol will interfere with the subsequent determination of metallic iron in by potassium dichromate titration. Therefore, after filtration and precipitate separation, the iodine-ethanol in filtrate must be fully removed at high temperature before determination. As a result, the operation is cumbersome and time-consuming with certain security risks. On the basis of this problem, an indirect determination method of metallic iron in desulfurization slag by potassium dichromate titration after iodine-ethanol separation was proposed, and the measurement conditions were optimized. Two samples with same mass were tested. One of them was firstly determined by potassium dichromate titration to obtain the total iron content. The metallic iron in another sample was leached with iodine-ethanol. The filtrate was discarded after filtration and separation, and the content of total iron in precipitate was determined using same method. The difference value of total iron mass was the metallic iron mass in one sample. Thus the content of metallic iron in sample could be indirectly calculated. The proposed method was applied for the determination of production samples of desulfurization slag (the mass fraction of metallic iron was in range of 0.63%-2.63%). The found results were consistent with those obtained by direct determination using potassium dichromate titration after iodine-ethanol separation. The relative standard deviations (RSD, n=6) were between 3.1% and 15.9%. Different masses of pure iron were added into two production samples of desulfurization slag for the recovery tests. The recoveries of metallic iron were between 96% and 108%.
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WANG Li-jie, YANG Zhi-qiang, AN Chun-yu, LI Tie. Indirect determination of metallic iron in desulfurization slag by potassium dichromate titration after iodine-ethanol separation. , 2020, 40(4): 44-48.
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