2016-Sustainable Industrial Processing Summit
SIPS 2016 Volume 6: Yagi Intl. Symp. / Metals & Alloys Processing
| Editors: | Kongoli F, Akiyama T, Nogami H, Saito K, Fujibayashi A |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2016 |
| Pages: | 480 pages |
| ISBN: | 978-1-987820-46-1 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Experimental Investigation of the Effects of Zinc on Burden Materials Metallurgical Properties and Primary Slag Formation of the Blast Furnace
Xuegong BI1;1WUHAN UNIVERSITY OF SCIENCE AND TECHNOLOGY, Wuhan, China;
Type of Paper: Regular
Id Paper: 45
Topic: 3
Abstract:
Due to a severe overcapacity, the Chinese steel industry is suffering from common operating difficulties. In order to reduce production cost and improve the competitiveness, it is propelled to use in great quantities raw materials with high zinc contents, including iron ores and retrieved wastes. As a result, the furnace state becomes unstable, the productive techno-economical indices go down and the target of decreasing cost is hard to realize. This paper focused on the behavior of zinc inside the blast furnace, the influences of zinc on raw materials metallurgical properties and the primary slag formation process as a particular, aiming at the formulation of right countermeasures for those blast furnaces that have severe zinc accumulation. An approach of soaking with zinc acetate solution was applied for adding zinc into the specimen of iron ores and coke. The low temperature reduction degradation property (the RDI index) and the reducibility (RI index) of sinter, the reactivity (CRI index) and strength after reaction (the CSR index) of coke were measured. The results showed with the zinc content increasing, for sinter, the RDI+3.15 and RDI+6.3 indices decreased and the RDI-0.5 greatly increased, while for coke, the CRI index decreased and the CSR index decreased. This implies that the zinc accumulation has negative effects on the burden column permeability and would also increase the fuel rate. The primary slag formation tests were conducted under simulating blast furnace conditions. The results demonstrated that the increase of zinc content rises the melt-down temperature, widens the softening 每 melting temperature range, increases the value of permeability index S, makes the differential pressure of burden column fluently vary, and, when the zinc content exceeds a certain level, the zinc content in the dripping primary slag increases dramatically. This implies that a severe zinc accumulation would bring about worsening of the cohesive zone properties, increase the amount of zinc entering into the lower blast furnace, and, therefore, as a consequence, cause a serious damage to the hearth and cooling equipments.