Wyniki wyszukiwania - BazTech

1

A new approach to the problems of recycling spent catalytic converters

Willner Joanna, Fornalczyk Agnieszka, Gajda Bernadeta, Sobianowska-Turek Agnieszka

Gaz, Woda i Technika Sanitarna

|

2024

|

Nr 1

40--46

EN

In the last decade the main application of precious metals has been the production of auto catalytic converters. The life time of catalytic converters is limited and after that time remains a rich source of platinum group metals. The article presents currently used pyro-and hydrometallurgical precious metals recovery methods. However, particular attention is dedicated to the new trends in biohydrometallurgy, focused on the possibility of using cyanogenic microorganisms potential in biological leaching of precious metals. A review of the achievements and results of laboratory tests for the extraction of precious metals from waste materials by bacteria leaching has been presented. The areas of research that require further explanation and solutions have been indicated. The article also gives suggestions for further laboratory work towards the use of cyanogenic microorganisms for recovery of platinum group metals from solid waste. The work also presents innovative solutions for the management of residues (specifically cordierite carriers) following the processing of used automotive catalytic converters through pyro-, hydro-, or bio-based methods.

PL

W ostatniej dekadzie głównym zastosowaniem metali szlachetnych była produkcja katalizatorów samochodowych. Żywotność katalizatorów jest ograniczona i po tym czasie pozostaje bogatym źródłem metali z grupy platynowców. W artykule przedstawiono obecnie stosowane metody odzyskiwania piro- i hydrometalurgicznego metali szlachetnych. Szczególną uwagę poświęcono jednak nowym trendom w biohydrometalurgii, skupiającym się na możliwości wykorzystania potencjału mikroorganizmów cyjanogennych w biologicznym ługowaniu metali szlachetnych. W pracy przedstawiono przegląd osiągnięć i wyników badań laboratoryjnych ekstrakcji metali szlachetnych z materiałów odpadowych metodą wymywania bakteryjnego, wskazano obszary badań wymagające dalszego wyjaśnienia i rozwiązań. W artykule przedstawiono także sugestie dotyczące dalszych prac laboratoryjnych,, w kierunku wykorzystania mikroorganizmów cyjanogennych do odzyskiwania metali z grupy platynowców z odpadów stałych. W pracy przedstawiono także innowacyjne rozwiązania w zakresie zagospodarowania pozostałości (w szczególności nośników kordierytowych) po przetworzeniu zużytych katalizatorów samochodowych metodami pirometalurgicznymi, hydrohydrometalurgicznymi i biohydrometalurgicznymi.

2

Hydrome-metallurgical waste management: Turning metal-enriched waste into valuable resources

Brožová Silvie, Brož Jiří, Ingaldi Manuela

Zeszyty Naukowe Akademii Morskiej w Szczecinie

|

2023

|

nr 75 (147)

107-113

EN

The convergence of hydrometallurgical waste management and the principles of the circular economy holds immense potential for addressing the challenges posed by metal-enriched waste. By turning waste into valuable resources through efficient metal extraction, this approach not only aligns with sustainable development goals but also contributes to the conservation of resources, reduction of waste, and the promotion of economic and environmental well-being. This article deals with the further possibilities of processing metal-bearing wastes in the form of steel drifts via hydrometallurgy. The main part of this research focuses on the development of suitable technology for the leaching of steel flakes to obtain selected non-ferrous metals, mainly zinc and lead, for economic and environmental reasons. Laboratory experiments are carried out to verify a suitable leaching agent in the form of high-temperature acid leaching, neutralizing leaching, and magnetic separation verified in lead seals. From the results of the experiments, a suitable technology for processing steel fumes is proposed.

3

The influence of activity coefficient and equilibrium constant models on the speciation of aqueous solutions of H2SO4–MgSO4–Al2(SO4)3 at 235 and 250 °C

Dickson Okechukwu Vincent, Deleau Thomas, Coquelet Christophe, Espitalier Fabienne, Lombart Julien, Tardy Antoine

Physicochemical Problems of Mineral Processing

|

2023

|

Vol. 59, iss. 5

art. no. 167497

EN

Supersaturation occurs in many industrial applications promoting reactive crystallisation between the reactants to form solutes. These solutes accumulate during precipitation, leading to the formation of scales on the inner walls of the reactor and particularly around the stirrer, causing modifications in the hydrodynamics. This encrustation is responsible for process shutdowns in continuous crystallisation processes. Supersaturation control is essential for industrial processes aimed at controlling or inhibiting the formation of these solids. Knowledge of mineral solubility and chemical speciation is required to account for the composition of the complexes in the system in their various solid or aqueous forms. This speciation is obtained by considering the thermodynamic equilibrium constants of the dissociation/complexation reactions involved in the system, the pressure, and the activity coefficients of the chemical species in their molecular or electrolyte form. From these thermodynamic quantities and the state of the system, we can predict the direction of the reaction. This study highlights the risk of the lack of experimental information on equilibrium constants at high temperatures and moderate pressures. Our goal is to evaluate the accuracy of existing models classically used to predict the equilibrium constant in such very hard conditions encountered in hydrometallurgical processes. Furthermore, we demonstrate the influences of equilibrium constants estimation and activity coefficient models on the speciation of H2SO4–Al2(SO4)3–MgSO4 systems, forming hydronium alunite and kieserite in the laterite liquor of hydrometallurgical processes.

4

Comparative study on removal of metallurgical silicon impurities by different acid leaching methods

Gao Zijie, Luo Dawei

Physicochemical Problems of Mineral Processing

|

2023

|

Vol. 59, iss. 2

art. no. 162331

EN

Hydrometallurgy is considered a promising method to produce solar-grade silicon (SOG-Si) from metallurgical-grade silicon (MG-Si) due to its advantages of low cost, simple operation, and easy control. In this paper, the effects of particle size of MG-Si, type of acid, leaching time, temperature, and liquid-to-solid ratio on the purification efficiency were investigated in an external field environment with the addition of ultrasound. The purification efficiencies of the two acid-leaching methods were compared. It was found that the simultaneous use of HCl + HNO3 was more effective than using only HCl for impurity removal in MG-Si: the extraction efficiencies of impurities Fe and Al were increased by 2.2% and 13.4%, respectively. The impurity contents in MG-Si before and after calcination pretreatment were also compared. This paper is expected to help researchers select the appropriate hydrometallurgical technique to reduce the impurity content in MG-Si.

5

Increase in the Free Finely-Dispersed Gold Recovery in the Flotation Cycle

Toktar Gulmira, Bakrayeva Akbota, Abdyldayev Nurgali, Banks Graig E., Kubaizhanov Alibek

Journal of Ecological Engineering

|

2023

|

Vol. 24, nr 1

115--119

EN

This article presents the results of a comparative study for the increase in the free finely dispersed gold recovery from the gold-bearing ore produced in a deposit in Kazakhstan. The following minerals were identified in the sample under X-ray phase analysis: chalcopyrite and pyrite, as well as in a finely disseminated state in silicate minerals. Gold in the ore is present mainly (40.09%) in the free form under the results of phase analysis. Flotation tests of ore beneficiation were performed in FML-1 and FML-3 flotation machines with chamber volumes of 1.0 and 3.0 liters. A flotation combined concentrate with a gold content of 15.3 g/t was obtained (concentrate yield 9.45%), with gold recovery into concentrate 82.79% in the optimal mode: the grind of 90% in the class -0.071 mm; consumption of reagents: C7 foaming agent – 30 and 60 g/t, sodium butyl xanthate – 60 and 120 g/t; the time of the main flotation – 10 minutes, the control flotation – 7 minutes, at pH = 9. Flotation tailings contained 0.33 g/t of gold. The recovery showed a fairly high 84.42% (yield of the total concentrate 20.93%) with the gold content of 7.1 g/t with the use of a sulfidizing agent (Na2S) and additional dispersion of the pulp at pH = 9.0. A gold-bearing concentrate was obtained containing 4.0 g/t Au at a fineness of -0.05 mm and 6.8 g/t Au at a fineness of +0.05 mm. The beneficiation of the pulp with a fineness of +0.05 mm gave the recovery into the final concentrate equal to 89.94%.

6

Otrzymywanie koncentratów tytanu z popiołów lotnych

Świnder Henryk

Inżynieria Mineralna

|

2023

|

no. 2, vol. 2

63--68

PL

Celem pracy było zwrócenie uwagi na możliwość wykorzystania popiołów lotnych ze spalania węgla kamiennego jako źródła koncentratów tytanu. Zrealizowane prace badawcze miały na celu określenie warunków obróbki wstępnej popiołów lotnych w procesie alkalicznej aktywacji termicznej za pomocą węglanu sodu i ich wpływu na wydzielania związków tytanu w procesach hydrometalurgicznej obróbki. Proces przeprowadzono dla mieszanek popiołu i węglanu sodu w stosunku wagowym 1 do 1,1. Otrzymane mieszaniny ogrzewano przez 1 godzinę w temperaturze 973K, 1023K i 1083K. Po ostudzeniu i rozdrobnieniu ługowano otrzymaną pozostałość poreakcyjną za pomocą kwasu chlorowodorowego i azotowego (V). Wyniki analizy chemicznej i skaningowej analizy mikroskopowej wraz z analizą EDS i analizą rentgenowską wykorzystano do określenia właściwości chemicznych i fizycznych badanych substratów i produktów obróbki popiołu lotnego. Przeprowadzono analizę możliwości wydzielania koncentratów tytanu z popiołów lotnych powstających w procesie spalania w kotłach pyłowych z wybranych krajowych elektrowni. Stwierdzono zależność stężenia tytanu w otrzymanym koncentracie od temperatury prowadzenia procesu aktywacji oraz od rodzaju kwasu w procesie obróbki hydrometalurgicznej. Zawartość tytanu w otrzymanych koncentratach wynosiła od 39,3% do 60,8%, co odpowiada zawartości tego pierwiastka w eksploatowanych obecnie rudach tytanu.

EN

The purpose of the study was to highlight the possibility of using fly ash from coal combustion as a source of titanium concentrates. The research work carried out was aimed at determining the conditions for pretreatment of fly ash by alkaline thermal activation with sodium carbonate and their effect on the release of titanium compounds in the hydrometallurgical process. The process was carried out for mixtures of ash and sodium carbonate in a weight ratio of 1 to 1.1. The resulting mixtures were heated for 1 hour at temperatures of 973K, 1023K and 1083K. After cooling and grinding, the resulting reaction residue was washed with hydrochloric acid and nitric acid (V). The results of chemical analysis and scanning microscopic analysis, together with EDS and X-ray analysis, were used to determine the chemical and physical properties of the tested substrates and fly ash treatment products. An analysis of the possibility of separating titanium concentrates from fly ash generated during the combustion process in pulverized fuel boilers of selected domestic power plants was carried out. The dependence of titanium concentration in the obtained concentrate on the temperature of the activation process and on the type of acid in the hydrometallurgical treatment process was found. The content of titanium in the obtained concentrates ranged from 39.3% to 60.8%, which corresponds to the content of this element in currently exploited titanium ores.

7

Sustainable development in the tinplate industry: refining tinplate leachate with cementation

Klimko Jakub, Urban Kobialkova Ivana, Piroskova Jana, Orac Dusan, Havlik Tomas, Klein Dusan

Physicochemical Problems of Mineral Processing

|

2020

|

Vol. 56, iss. 1

219--227

EN

Tin sludge produced during tin electroplating of steel sheet is an interesting secondary source of tin. Dried sludge usually contains more than 50% tin. Hydrometallurgical sludge treatment consists of several steps, including leaching in hydrochloric acid and electrolytic recovery of tin. The electrowinning process is negatively affected by the presence of impurities such as antimony and bismuth, which can cut overall current efficiency to 11% as well as reducing the quality of recovered tin. It is appropriate therefore to remove these impurities from the leachate before the electrowinning steps. This work studies the refining of leachate using cementation. The experiments were carried out at temperatures of 20, 40 and 60 °C at solid to liquid ratios of 1:60, 2:60, 3:60 and 4:60 using tin and iron dust as cementing metals. The leachates were mixed at a constant rate of 400 rpm during all cementation experiments. Effective removal of impurities was achieved in the case of iron powder cementation at s/l ratio 2:60 and temperature 20 °C. This cementation removed 98.49% bismuth and 99.14% antimony from the leachate solution. Electrolysis efficiency was increased from 11 to 71% after leachate refining. Antimony and bismuth were not detected in the final product obtained from refined electrolyte by means of electrolysis.

8

Hydrometalurgiczny recykling cynku z odpadów cynkowania ogniowego

Rudnik Ewa, Chat Karolina, Szatan Leszek

Rudy i Metale Nieżelazne Recykling

|

2019

|

R. 64, nr 2

19--21

PL

Cynkowanie ogniowe generuje pewne odpady, jak: zgary powstające w kąpieli i popiół pocynkowniczy tworzący się na powierzchni stopionego metalu. Ze względu na wysoką zawartość cynku oba rodzaje odpadów można traktować jako wartościowe surowce wtórne. W pracy przedstawiono wyniki badań, które wskazują na możliwość otrzymywania cynku metalicznego jako produktu końcowego, o jakości odpowiedniej do ponownego wykorzystania w procesie cynkowania zanurzeniowego. Odpady przemysłowe scharakteryzowano pod względem składu pierwiastkowego i fazowego. Przeprowadzono ługowanie materiału w roztworach kwasu siarkowego, w czasie którego określono wpływ stężenia kwasu i stosunku fazy stałej do ciekłej na skuteczność ługowania cynku i stopień zanieczyszczenia ługu potrawiennego. Roztwór otrzymany w czasie ługowania poddano oczyszczaniu, a następnie przeprowadzono elektrolityczny odzysk metalu.

EN

Hot dip galvanizing (HDG) generates some wastes, like zinc dross formed in the bulk of the bath and zinc ash produced on the bath’s surface. Due to high metal contents, both residues can be recycled as valuable secondary raw materials. This work reports hydrometallurgical treatment of the zinc ash to recover zinc with a quality suitable to its reusing in the HDG process. The industrial waste was characterized in terms of the elemental and phase compositions, leaching behaviour in sulfuric acid solutions. The influence of acid concentration and solid to liquid ratio on the efficiency of zinc dissolution and the degree of leachate contamination was investigated. The leaching process was followed by the solution purification and further metallic zinc electrowinning.

9

Study on leaching kinetics of laterite ore using hydrochloric acid

Li Jinhui, Xu Zhifeng, Wang Ruixiang, Gao Yang, Yang Yang

Physicochemical Problems of Mineral Processing

|

2019

|

Vol. 55, iss. 3

711--720

EN

The process of atmosphere-pressure acid leaching of laterites has attracted considerable attention in the nickel industry in recent years. However, the leaching kinetics of laterite using hydrochloride acid has not yet been fully researched. In this paper, the mineral analysis of the ore was carried out, and the leaching mechanism of different minerals at different time was studied comprehensively. The kinetics analysis of the leaching process of nickel, cobalt and manganese showed that the kinetics model of diffusion controlling was suitable and could be described by the linear equation, 1-3(1-a)2/3+2(1-a)=k2t. Based on the linear equation and the Arrhenius equation, the values of activation energy of metal leaching can be deduced (11.56 kJ/mol for nickel, 11.26 kJ/mol for cobalt and 10.77 kJ/mol for manganese). Study of leaching mechanism shows that the order of these minerals dissolution is: goethite, lizardite, magnetite and hematite. Due to the original or product of silica, magnetite, hematite and talc, they can form the solid film which hinders the leaching of valuable metals. Thus, the diffusion controlling step is inner diffusion, namely solid film diffusion controlling.

10

Optimization and kinetics studies of lead concentrate leaching using fluoroboric acid

Sabouti Arash, Rezai Bahram, Hoseinian Fatemeh Sadat, Moradkhani Davood

Physicochemical Problems of Mineral Processing

|

2019

|

Vol. 55, iss. 4

1014--1027

EN

In this study, the feasibility of lead dissolution from lead concentrate using fluoroboric acid by hydrometallurgical method was investigated in order to aviod the disadvantages of the pyrometallurgical processes. The effects of important operating parameters such as leaching time, liquid/solid ratio, stirring speed, temperature and fluoroboric acid concentration on the lead recovery were investigated using response surface methodology (RSM) based on the central composite design (CCD) model. The results show that the optimum conditions for the high lead recovery were: leaching time= 30 min, liquid/solid ratio= 10, stirring rate= 500 rpm, temperature= 80oC and fluoroboric acid concentration= 3.35 mol/L. More than 94% of lead was recovered in the optimum conditions. The results indicated that the liquid/solid ratio, fluoroboric acid concentration, temperature and leaching time were the most effective parameters on the process efficiency, respectively. Dissolution kinetics studies of lead in the fluoroboric acid were also evaluated. The chemical reaction was determined as the controlling mechanism of reaction at the shrinking core model. The activation energy was determined using Arrhenius model as 5.99 kJ/mol.

11

Considering the influence of calcium on EAF dust acid leaching

Havlik Tomas, Miskufova Andrea, Turek Peter, Urban Kobialkova Ivana

Physicochemical Problems of Mineral Processing

|

2019

|

Vol. 55, iss. 2

528--536

EN

This work focuses on the hydrometallurgical processing of EAF steelmaking dust in laboratory conditions. The behavior of calcium under the influence of sulphuric acid as the leaching agent is discussed. Due to calcium presence the acid is continuously consumed, gradually leaching the calcium phase from EAF dust as well as other zinc- and iron-containing phases. A thorough composition analysis of the input sample of EAF dust was performed. A kinetic study of calcium showed that its leaching is a very fast process, but most of the calcium reacting with sulphuric acid is precipitated from the solution in the form of CaSO4∙2H2O. This causes greater sulphuric acid consumption, and therefore it is necessary to study the calcium behavior during processing of EAF dust. This work is narrowed with calcium behavior during leaching of EAF dust in sulphuric acid and effect of calcium to extraction other metals into solution.

12

Next generation technology for utilization of alumina rich iron ore tailings in India

Mukopadhyay Sudipta, Periyasamy Muthaimanoj

New Trends in Production Engineering

|

2019

|

Vol. 2, Iss. 1

78--85

EN

Accumulation of low-grade iron ore tailings (IOTs) generated during the processing of high-grade iron ore has become a great threat to environment. Although wide range of research works has carried out to recover the iron values from the IOTs, but the solid recovery value has limited to ca. 50% in Indian context. In order to attain a maximum iron recovery and to utilize these solid wastes for future needs, an attention has shed on the topics of hydrometallurgy and applied nanomaterial synthesis from IOTs. Iron containing nanoparticles (ICNs) have huge potential in environmental and energy related applications. A wide range of synthesis methods has developed to produce ICNs from the mine waste. It is evident from the recent research works that converting waste materials into value added products are gaining more attentions. Objective of this review is to analyse the green synthesis routes to prepare ICNs from mine waste, starting from the physio chemical identification of waste material followed by discussion on various methods of ICNs synthesis routes from mine waste. It includes selective leaching method. Finally, the use of ICNs for environmental application had discussed in brief.

13

Recycling of Spent Hydrodehalogenation Catalysts – Problems Dealing with Separation of Aluminium

Weidlich Tomas, Kamenicka Barbora

Inżynieria Mineralna

|

2019

|

R. 21, nr 1

177--182

EN

Our study is focused on utilization and recycling of copper and nickel applicable for reductive degradation of tetrabromobisphenol A (TBBPA), the high use brominated flame retardant for printed circuit boards. Deactivated and/or poisoned hydrodebromination catalysts are produced by reductive destruction of brominated phenol (TBBPA) dissolved in alkaline aqueous solution using Raney Al-Ni and/or Devarda´s Al-Cu-Zn alloys. Spent metallic slurry is treated with aqueous sulfuric acid to dissolve residual aluminium and/or zinc and decanted residual metal is subsequently treated under oxidation conditions and dissolved in excess of mineral acid by co-action of oxidant. The corresponding metal salt is separated from corresponding leachates containing excess of acid by evaporation and recycling of volatile components. Obtained copper or nickel salts were used as sources of Raney type hydrodebromination catalysts produced for in-situ by action of NaBH4.

PL

Nasze badania koncentrują się na wykorzystaniu i recyklingu miedzi i niklu stosowanym do redukcyjnej degradacji tetrabromobisfenolu A (TBBPA), wysokowydajnego bromowanego środka zmniejszającego palność płytek obwodów drukowanych. Dezaktywowane i/lub zużyte katalizatory hydrodebromowania wytwarza się przez redukcyjne zniszczenie bromowanego fenolu (TBBPA) rozpuszczonego w alkalicznym roztworze wodnym przy użyciu stopów Al-Cu-Zn Raneya Al-Ni i/lub Devarda. Zużyta metaliczna zawiesina jest traktowana wodnym roztworem kwasu siarkowego w celu rozpuszczenia resztkowego aluminium i/lub cynku, a zdekantowany pozostały metal jest następnie obrabiany w warunkach utleniania i rozpuszczany w nadmiarze kwasu mineralnego przez współdziałanie utleniacza. Odpowiednia sól metalu jest oddzielana od odpowiednich odcieków zawierających nadmiar kwasu przez odparowanie i zawracanie lotnych składników. Otrzymane sole miedzi lub niklu zastosowano jako źródła katalizatorów hydrodebromowania typu Raneya wytworzonych in situ przez działanie NaBH4.

14

Prof. dr hab. inż. Jerzy Ostoja Sędzimir (1924-2018)

Gumowska W.

Rudy i Metale Nieżelazne Recykling

|

2018

|

R. 63, nr 7

3--4

15

Pressure leaching of sulfide concentrate produced by Lubin Concentrator (KGHM Polska Miedz SA, Poland)

Matuska S., Ochromowicz K., Chmielewski T.

Physicochemical Problems of Mineral Processing

|

2018

|

Vol. 54, iss. 3

781--792

EN

The rapidly declining quality of ores and concentrates produced by Lubin Concentrator (KGHM) makes the flotation concentrates exceptionally difficult-to-process by flash smelting. Currently, a hydrometallurgical process, using sulfuric acid with the presence of oxidants as a leaching medium, seems to be either a reasonable alternative or a complementary option to pyrometallurgy. The unique lithological, mineralogical and chemical properties of the concentrate were considered in a selection of the process route. Results of a pressure leaching of the copper sulfide concentrate from Lubin Concentrator (ZWR Lubin) with oxygenated aqueous H2SO4 solutions are presented. The effect of temperature from 120 to 200 °C, initial concentration of H2SO4 from 60 to 100 g/dm3, and oxygen partial pressure ranging from 0.5 to 2.0 MPa were investigated. The pressure leaching appeared to be an efficient process for recovering copper from the Lubin concentrate. At optimal leaching conditions (140 °C, 100 g/dm3 H2SO4, 1.0 MPa O2) 96% of Cu was extracted after 4 h.

16

Studies on hydrometallurgical processes using nuclear techniques to be applied in copper industry. 2. Application of radiotracers in copper leaching from fl otation tailings

Rogowski M., Smoliński T., Pyszynska M., Brykała M., Chmielewski A. G.

Nukleonika

|

2018

|

Vol. 63, No. 4

131--137

EN

The use of radiotracers in the present study is intended to replace traditional steps of metal quantitative analysis (solution sampling and instrumental chemical analysis) and to allow real-time measurements of metal concentrations during the leaching process. In this study, 64Cu, an isotope of copper, was selected as a radiotracer. Samples of copper flotation tailings were irradiated in the Maria research reactor (Świerk, Poland) and mixed with an inactive portion of the milled flotation waste. The leaching process was carried out in a glass reactor, and the radiation spectrum was measured using a gamma spectrometer. The material was then treated using various acids (sulphuric acid, nitric acid, acetic acid, citric acid, and ascorbic acid) in a wide range of their concentrations. Experiments with the radiotracer were conducted in sulphuric and nitric acids. The amount of the leached metal (copper) was calculated on the basis of the peak area ratio in the gamma-ray spectrum of the activated tailings and standard samples. Inductively coupled plasma mass spectrometry (ICP-MS) was also used to analyse the metal content. Maximum recovery of 56% Cu was achieved using 9 M HNO3, whereas the recovery was lowest for ascorbic acid (1%). Both analytical methods were compared, and the results presented in this paper are in good agreement with radiometric measurements obtained using ICP-MS analysis.

17

Studies on hydrometallurgical processes using nuclear techniques to be applied in copper industry. I. Application of 64Cu radiotracer for investigation of copper ore leaching

Smoliński T., Rogowski M., Brykała M., Pyszynska M., Chmielewski A. G.

Nukleonika

|

2018

|

Vol. 63, No. 4

123--129

EN

Scientific objective of this work was elaboration of radiometric method for the development of hydrometallurgical process for recovery of Cu from the copper ore. A neutron activation analysis (NAA) was identified as a very convenient tool for the process investigation. The samples of copper ore were activated in a nuclear reactor. The parameters of the neutron activation were calculated. Radioisotope 64Cu was selected as an optimal tracer, and it was used for the investigation of the leaching process. During the experiments, various processes applying leaching media such as sulphuric acid, nitric acid, and organic acids were investigated. The recovery of the metals using sulphuric acid was insufficient, around 10%. Investigated organic media also did not meet expectations. The best results were obtained in experiments with nitric acid. Up to 90% of Cu and other metals were extracted from the copper ore. Copper concentration calculations obtained by NAA were confimed by inductively coupled plasma mass spectrometry (ICP-MS) technique. Both techniques gave comparable results, but the advantage of the NAA is a possibility for easy online measurements without shutting down or disturbing the system.

18

Review on Oxide Formation and Aluminum Recovery Mechanism during Secondary Smelting

Osoba L.O., Owolabi O.B., Talabi S.I., Adeosun S.O.

Journal of Casting & Materials Engineering

|

2018

|

Vol. 2, no. 2

45-51

EN

The remelting, refining, and casting process of aluminum alloys often generate aluminum dross containing primarily oxides and nitrides of aluminum and entrapped metallic aluminum at the surface of the molten metal as a result of reactions within the furnace atmosphere at elevated temperatures. The handling of dross is an expensive but necessary activity during aluminum smelting. Furthermore, the amorphous Al2O3 oxide film formed on the pure molten aluminum surface due to the liquid metal randomly distributed atoms is impermeable to the diffusion of aluminum metal and oxygen. In amorphous materials, there is a low mobility of the charge carriers and an absence of preferred diffusion paths. This film can transform to crystalline Al2O3 by nucleation and grows with time and opportunity. This review discusses the mechanism of oxide formation and the aluminum metal recovery processes.

19

Preliminary Investigation on Leaching Behavior of Zinc ash

Rudnik E., Włoch G., Szatan L.

Archives of Metallurgy and Materials

|

2018

|

Vol. 63, iss. 2

801--807

EN

Oxide fraction of industrial zinc ash from hot dip galvanizing was characterized in terms of composition and leaching behaviour in 10% sulfuric acid solution. Waste product contained about 68% Zn, 6% Cl, 3% Al, 1% Fe, 0.7% Si, 0.5% Pb and minor percentages of other metals (Mn, Cu, Ti etc.). It consisted mainly of zinc oxide contaminated with metallic zinc, zinc hydroxide chloride and silica. Dissolution of the metals from the material was determined as a function of solid to liquid ratio (50-150 kg/m3), temperature (20°C and 35°C) and agitation rate (300 and 900 rpm). The best results (50 g/dm3 Zn(II) at 78% zinc recovery) were obtained for 100 kg/m3 and the temperature of 20°C. Increase in the agitation rate had weak effect on the zinc yield. The final solutions were contaminated mainly by Fe(II, III) ions. Leaching of the material was an exothermic process with the reaction heat of about 800 kJ/kg.

20

Influence of H2O2 and O3 on PGM Extraction from Used Car Catalysts

Fornalczyk A., Willner J., Gajda B., Sedlakova-Kadukova J.

Archives of Metallurgy and Materials

|

2018

|

Vol. 63, iss. 2

963--968

EN

Catalytic converters contain the catalytic substance in their structure, which is a mixture of Platinum Group Metals (PGMs). The prices of these metals and a growing demand for them in the market, make it necessary to recycle spent catalytic converters and recovery of PGMs. In the study, the effect of ozone and hydrogen peroxide application on the possibility of extracting PGM from used car catalysts was investigated. The catalytic carrier was milled, sieved and then the fractions with the desired grain size were treated with the appropriate HCl mixture and 3%, 5%, 10%, 15% and 30% H2O2, respectively, and the tests were also carried out at temperature 333 K. Ozone tests were conducted with the O3 flow in the range of 1,3,5 g/h. Samples for analysis were collected after 30 min, 1 h, 2 h, 3 h and after 4 h, respectively. The residue after the experiments and filtration process was also analysed. The obtained results confirmed the assumption that PGMs can be extracted using hydrochloric acid with the addition of H2O2 or ozone as oxidants. It allows to significantly intensify the carried out reactions and to improve the rate of PGMs transfer to the solution.