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1

Determination of ZnO Amount in Electric Arc Furnace Dust and Temperature Dependence of Leaching in Ammonium Carbonate by Using of X-Ray Diffraction

Havlik T., Maruskinova G., Miskufova A.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 2

653--658

EN

Zinc is present in electric arc furnace dust (EAFD) mainly in two basic minerals, namely as franklinite ZnFe2O4 and/or zincite ZnO. While zincite is relatively reactive and easily treatable, franklinite is considerably refractory, which causes problems during EAFD processing. In this work EAFD containing 18.53% Zn was leached in water solution of ammonium carbonate. This leaching solution selectively leaches zincite, while franklinite is refractory and stable against leaching in this case. The temperature dependence of zinc leaching from EAFD was studied and the activation energy EA was determined by two methods: 1.) classically based on zinc chemical analyses from the leaching solution and 2.) by using of X-Ray diffraction qualitative phase analyses of leaching residues. The determined values of activation energies 37.41 and 38.55 kJmol-1 match perfectly, which show the excellent possibility of using X-Ray diffraction toward the study of leaching kinetics at properly chosen experimental conditions. The important result is the determination of the amount zincite and franklinite in EAFD, which is not possible by using of classical chemical methods.

2

Alkaline leaching of zinc from stainless steel electric arc furnace dusts

Stefanova A., Aromaa J., Forsen O.

Physicochemical Problems of Mineral Processing

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2015

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Vol. 51, iss. 1

293--302

EN

Stainless steel production generates dust and sludge that are considered as a harmful waste. These dusts contain also valuable metals but extraction and recovery of valuables is difficult due their complex composition. Zinc is the most troublesome element in the dust and it hinders direct recycling of dust back into furnaces. In this paper two different stainless steel electric arc furnace dusts (EAF1 and EAF2) from Outokumpu Stainless (Tornio, Finland), were leached using NaOH solutions. The purpose was to selectively leach out zinc from the dusts and to find factors that affected most dissolution of zinc. From all leaching factors temperature, agitation speed and NaOH concentration were found to be statistically strongly significant, whereas a liquid-to-solid ratio and bubbling gas were only somehow significant. Two experiments from the test series gave clearly higher zinc extraction, that is around 60% for EAF1 and 30% for EAF2. For those experiments, a strong 8 M NaOH solution with the high temperature and agitation speed was used but bubbling gas and liquid-to-solid ratio changed. Zinc was leached selectively and practically no iron, chromium and nickel dissolved.

3

Briquetting of EAF Dust for its Utilisation in Metallurgical Processes

Magdziarz A., Kuźnia M., Bembenek M., Gara P., Hryniewicz M.

Chemical and Process Engineering

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2015

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Vol. 36, nr 2

263--271

EN

Dust generated at an electric arc furnace during steel production industry is still not a solved problem. Electric arc furnace dust (EAF) is a hazardous solid waste. Sintering of well-prepared briquetted mixtures in a shaft furnace is one of possible methods of EAFD utilisation. Simultaneously some metal oxides from exhaust gases can be separated. In this way, various metals are obtained, particularly zinc is recovered. As a result, zinc-free briquettes are received with high iron content which can be used in the steelmaking process. The purpose of the research was selecting the appropriate chemical composition of briquettes of the required strength and coke content necessary for the reduction of zinc oxide in a shaft furnace. Based on the results of the research the composition of the briquettes was selected. The best binder hydrated lime and sugar molasses and the range of proper moisture of mixture to receive briquettes of high mechanical strength were also chosen and tested. Additionally, in order to determine the thermal stability for the selected mixtures for briquetting thermal analysis was performed. A technological line of briquetting was developed to apply in a steelworks.

4

Stabilization and solidification of electric arc furnace dust originating from steel industry by using low grade MgO

Bayraktar A. C., Avşar E., Toröz I., Alp K., Hanedar A.

Archives of Environmental Protection

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2015

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Vol. 41, no. 4

62--66

EN

In this study, solidification/stabilization (S/S) of electric arc furnace dust (EAFD) which is generated during the production of steel from scrap metals and classified as hazardous waste were investigated by using different ratios of cement and low grade MgO (LG MgO) as binding agents. Type I PC 42.5 R portland cement and LG MgO which contains 70–80% MgO were used. S/S blocks that contain different ratios of binding agents which have 1/0.5 – 1/1 – 1/2 – 1/3 – 1/4 – 1/5 cement/LG MgO ratio and S/S blocks which contain only cement and no LG MgO agents were prepared. These blocks, which contain 3 different waste ratios according to weight, 20%, 30% and 40% respectively, were produced and exposed to 28-day water purification. At the end of the purification process, S/S blocks were extracted using TCLP (Toxicity Characteristic Leaching Procedure) tests in order to determine the leaching behavior of Zn, Pb, and Cd in S/S blocks. By the end of this study, it was concluded that the recovery of EAFD is possible and applicable by immobilization. The findings of the study concluded that environmental performances or structural properties of blocks contain 30% waste by weight are suitable. This method is a proper one for recovering and treatment of EAFD with mixture of cement and LG MgO.

5

Dobór wartości pH roztworów w hydrometalurgicznym procesie przerobu wysokocynkowych pyłów pochodzących z łukowych pieców elektrycznych

Suliga A., Derda W.

Hutnik, Wiadomości Hutnicze

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2012

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Vol. 79, nr 12

856--859

PL

Niniejsza praca koncentruje się na procesie przerobu pyłów z łukowych pieców elektrycznych (ŁPE) traktując je jako źródło cynku. Przemywanie wodą mające na celu usunięcie zanieczyszczeń, głównie soli chlorkowych przed zasadniczymi procesami hydrometalurgicznymi, powoduje straty odzyskiwanego metalu. Podejście do procesu przemywania oraz ługowania jak do reakcji zachodzących w ogniwach elektrochemicznych pozwala na teoretyczne opracowanie warunków prowadzenia procesu ograniczających straty cynku. Przegląd literatury wskazuje, że odpowiedni dobór wartości pH roztworu umożliwia optymalizację procesu odzysku cynku.

EN

This paper focuses on the processing of electric arc furnaces dust (EAFD) by treating its as a source of zinc. Dust washíng with water to remove pollutants, principally chloride salt as a prehydrometallurgical process causes the losses of amount of metal. Treatíng the washing and leaching as a reactions occurring in electrochemical cells enables theoretical description of process and in effect decrease of zinc losses. The literature review indicates that proper selection of the pH values of solution allows to optimize the zinc recovery.

6

Recovery of zinc from arduous wastes using solvent extraction technique. Part I. Preliminary laboratory studies

Gotfryd L., Chmielarz A., Szołomicki Z.

Physicochemical Problems of Mineral Processing

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2011

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Vol. 47

149-158

EN

Solvent extraction technique with 40 volume percent of bis(2-ethylhexyl)phosphoric acid as an extractant was applied for recovery of zinc from technological solutions. Crude zinc oxides from Waelz processing of electric arc furnace dusts or ferrous waste of zinc hydrometallurgy were used for preparation of feed solutions by leaching them with diluted sulfuric acid and by preliminary hydrometallurgical purification. The studies were conducted step by step from elementary laboratory experiment to advanced level of pilot plant tests in a continuously operating installation consisting of a counter-current set of mixer-settler type extractors and necessary equipment. The paper describes the course and results of initial laboratory works undertaken to choose proper extractant and establish conditions for further successful zinc extraction in the pilot plant installation.

7

Recovery of zinc from arduous wastes using solvent extraction technique. Part II, Pilot plant tests

Gotfryd L., Chmielarz A., Szołomicki Z.

Physicochemical Problems of Mineral Processing

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2011

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Vol. 47

249-258

EN

Solvent extraction technique using 40 vol. % bis(2-ethylhexyl)phosphoric acid as an extractant was applied for recovery of zinc from technological solutions. Crude zinc oxides from Waelz processing of electric arc furnace dusts or ferrous waste of zinc hydrometallurgy were used for preparation of feed solutions by leaching them with diluted sulfuric acid and by pre-liminary hydrometallurgical purification. The studies were conducted step by step from labor-atory to advanced pilot plant tests in continuously operating installation. Part II describes preparations and results of pilot plant counter-current experiments performed using laboratory extractive system, built from a train of mixer-settler type extractors, set in changeable countercurrent manner, necessary pumps and automation systems, coupling pH measurements with neutralization agent supply. Excellent results in a form of very pure zinc sulfate solutions were obtained. ZnSO4 concentrations are appropriate and the purity of the strip solutions very good. Comparison of natural and accelerated method of zinc extraction is done.

8

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.

9

Odzysk cynku z wybranych odpadów hutniczych

Ostrowska P., Mierzwa K.

Hutnik, Wiadomości Hutnicze

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2007

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Vol. 74, nr 7

369-373

PL

Procesy metalurgiczne wytwarzają duże ilości odpadów w postaci pyłów, szlamów oraz ścieków, stanowiąc poważne zagrożenie dla środowiska naturalnego. Niektóre z tych odpadów pod względem ich składu chemicznego, a zwłaszcza znacznej zawartości cynku, mogłyby stanowić cenny materiał wsadowy w hutnictwie metali nieżelaznych. W artykule przedstawiono metody odzysku metali z odpadów hutniczych, z uwzględnieniem metod pirometalurgicznych i hydrometalurgicznych.

EN

Metallurgical processes produce huge amount of waste materials in the form of dusts, sludges and waste water, which generate serious danger to natural environment. That waste materials for the sake of chemical composition, especially significiant amount of zinc, could be valuable charge material in non-ferrous metallurgy. The paper presents methods of recovery valuable metals from metallurgical waste taking pyrometallurgical and hydrometallurgical methods into consideration.