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Study of recycling blast furnace dust by magnetization roasting with straw charcoal as reductant

Ju Jinrong, Feng Yali, Li Haoran, Zhang Qian

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 3

art. no. 149265

EN

Blast furnace dust generated in the iron-making process not only contains a large amount of iron but also the widely used non-ferrous metal zinc, which is classified as hazardous waste. In this study, the process of recycling blast furnace dust by magnetization roasting with straw charcoal as the reductant is proposed, and the mechanism of magnetization roasting was explored through thermodynamic analysis, X-ray diffraction analysis, and thermogravimetric analysis. The results for the thermodynamic analysis showed that the reduction of blast furnace dust by the straw charcoal was feasible theoretically. The increase in the roasting temperature not only promoted the reduction of hematite (Fe2O3) but also reduced zinc ferrite (ZnFe2O4) to Fe3O4 and ZnO. The results showed that almost all Fe2O3 and ZnFe2O4 in the blast furnace dust were reduced to Fe3O4 and ZnO under the conditions of straw charcoal amount of 6%, the roasting temperature of 750℃, and the roasting time of 60 min. Then, the iron concentrate with the iron recovery of 85.61% and an iron grade of 63.50% was obtained by the magnetic separation. Meanwhile, the grade of zinc in the iron concentrate was 0.19%. Finally, the flowsheet of simultaneously recovering iron and zinc from the blast furnace dust was put forward, which could realize that 85.61% of iron was recovered and 92.57% of zinc was extracted into the solution.

2

Effects of the fixed carbon and ash in blast furnace dust on its co-reduction with seaside titanomagnetite

Wang Xiaoping, Hu Tianyang, Chen Chuanzhong, Sun Tichang

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 5

1323--1337

EN

Previous research has found that the fixed carbon in blast furnace dust (BFD) could be used as the reductant of co-reduction roasting of the iron oxides in seaside titanomagnetite and BFD to replace coals. This research studied the influence mechanism of the fixed carbon and ash in BFD on coreduction.Results showed that both fixed carbon and ash in BFD promoted the reduction of iron, while ash had adverse effect on separation of titanium and iron. The main mechanism was as follows: The ash in BFD accelerated melting. In addition, the iron oxide in the ash of BFD could be reduced to metallic iron cores more easily in the initial stage, providing the site of inhomogeneous core and promoting the aggregation and growth of metallic iron. Furthermore, the fixed carbon mainly reacted with iron ore by solid-solid reaction, leading to a rapid reduction rate and a high utilization rate of fixed carbon.

3

Wybrane aspekty odzysku metali z pyłów pochodzących z łukowych pieców elektrycznych w procesie pirometalurgicznym

Suliga A., Derda W.

Hutnik, Wiadomości Hutnicze

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2011

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Vol. 78, nr 5

348--352

PL

Artykuł koncentruje się na recyklingu pyłów z łukowych pieców elektrycznych traktując je jako źródło cennych pierwiastków: cynku, ołowiu i żelaza. Zastosowanie procesu pirometalurgicznego pozwala na jednoczesne wykorzystanie pyłów stalowniczych oraz pyłu wielkopiecowego w charakterze materiału wnoszącego węgiel, niezbędny w procesie redukcji związków cynku i ołowiu. Opracowanie technologii opartej na tego typu procesie pozwoliłoby na zagospodarowanie niebezpiecznych dla środowiska naturalnego odpadów przemysłu metalurgicznego, a jednocześnie na obniżenie kosztów tego typu technologii. Badania laboratoryjne wskazują, że dodatek pyłu wielkopiecowego w ilości 20÷30 % masy do pyłu stalowniczego umożliwia recykling cynku, żelaza i ołowiu na ekonomicznie uzasadnionym poziomie.

EN

This paper focuses on the recycling of electric arc furnaces dust by treating it’s as a source of valuable elements such as zinc, lead and iron. Use of the pyrometallurgical process allows on the simultaneous utilization of EAF Dusts and the blast furnace dust as a reducing agent bringing carbon indispensable in the reduction of zinc and lead oxides. Working out the technology based on this type of process would permit on bringing into cultivation of dangerous metallurgical industry wastes for natural environment and simultaneously to reduce the investment cost of this type technology. The laboratory scale tests indicate that the addition of blast furnace dust in amount of 20÷30 mass. % to the EAF Dust enables recycling of zinc, lead and iron on the economically well-founded level.