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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

Properties of organic coatings containing pigments with surface modified with a layer of ZnFe2O4

Nechvílová K, Kalendová A

Advances in Science and Technology. Research Journal

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2015

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Vol. 9, nr 28

51--55

EN

This work is focussed on the properties of organic coatings containing pigments whose surface was chemically coated with zinc ferrite (ZnFe2O4) layer. Four silicate types with different particle shapes were selected as the cores: diatomite, talc, kaolin and wollastonite. The untreated particles exhibit a barrier effect. The aim of this project was to apply the surface treatment approach with a view to enhancing not only the model paint films’ anticorrosion properties but also their resistance to physico- mechanical tests pursuant to ISO standards (cupping, bending, impact, adhesion). Other parameters examined included: particle size and morphology, density of the modified pigment, oil consumption, pH, conductivity, and electrochemical properties of the paint film. A solvent-based epoxy-ester resin was used as the binder and also served as the reference material. The pigment volume concentration (PVC) was 1% and 10%. During the last stage of the experiment, the paint films were exposed to a corrosive environment stimulating seaside conditions or conditions roads treated with rock salt. The accelerated cyclic corrosion test in a neutral salt mist atmosphere was conducted for 864 hours. The results served to ascertain a suitable environment for organic coatings.

3

Wpływ struktury związków chemicznych typu (Zn,Fe)S na kinetykę i strukturę produktów procesu ich utleniania

Kulawik S., Michalski R., Kapias P.

Rudy i Metale Nieżelazne Recykling

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2014

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R. 59, nr 4

157--163

PL

Rozpoznanie optymalnych warunków procesu prażenia w warunkach fluidalnych, w zależności od rodzaju stosowanych surowców i ich własności, ma zasadniczy wpływ na własności chemiczne i strukturalne prażonki a tym samym, na uzysk cynku w metodzie hydrometalurgicznej. Aktualnie, światowa produkcja cynku oparta jest na przerobie koncentratów siarczkowych, w których sfaleryty (Zn,Fe)S są dominującym nośnikiem cynku. Przedstawiono preparatykę wytwarzania związku (Zn,Fe)S o różnej zawartości Fe, zbadano podstawowe własności spreparowanych sfalerytów, takie jak: struktura, temperatura zapłonu i kinetyka procesu utleniania. Zbadano własności fizykochemiczne i strukturalne produktów procesu utleniania spreparowanych sfalerytów. Stwierdzono wpływ zawartość żelaza w sfalerytach, oraz wpływ temperatury, na jakość produktów po procesie utleniania. Żelazo po procesie utleniania występuje w postaci trudno ługowanego ferrytu cynku — ZnFe2O4, którego ilość jest zależna od ilości żelaza w prażonym surowcu. Nie stwierdzono istotnego wpływu zawartości żelaza w sfalerycie na kinetykę ich utleniania.

EN

Recognition of optimal roasting conditions in the fluidized bed, depending on used raw materials type and their properties, has a principal influence on chemical and structural properties of roasted ore and yield of zinc, using hydrometallurgical method. Currently, global production of zinc is based on processing of sulfide concentrates, in which (Zn,Fe)S sphalerites are dominant zinc bearing elements. The studies were carried out on the laboratory scale. The paper presents preparation of (Zn,Fe)S with different Fe content and examination of such basic properties of the prepared sphalerites, as: structure, ignition temperature and oxidation kinetics. Physicochemical and structural properties of the products from oxidation process of prepared sphalerites were examined. The influence of iron content in sphalerites and temperature on quality of the products after oxidation was observed. Iron after oxidation has a form of leaching-resistant zinc ferrite — ZnFe2O4 and its quantity depends on iron content in the roasted raw material. No significant impact of iron content in sphalerite on kinetics of their oxidation was observed.