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1

Innovative hydrometallurgy for galvanic sludge sustainable recovery

Brožová Silvie, Drápala Jaromír, Brož Jiří, Macháčková Adéla

System Safety : Human - Technical Facility - Environment

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2023

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Vol. 5, iss. 1

46--56

EN

The manuscript explores the feasibility of recovering zinc and iron from waste galvanic sludge generated during galvanic plating processes. Galvanic sludge, characterized by elevated concentrations of heavy metals, represents a suitable candidate for hydrometallurgical recycling. The primary objective of the experimental and practical phases was to extract zinc and iron through the leaching of galvanic sludge. Leaching procedures were conducted using sulfuric acid at varying temperatures and time durations, augmented by the introduction of oxidizing agents such as hydrogen peroxide or ozone. Subsequent separation of the leach and filtrate was achieved through filtration. The leachate underwent additional processing involving the precipitation of iron and other metals, employing diverse agents. Following further filtration, electrolysis was employed to attain pure zinc on the cathode, utilizing an electrical voltage of approximately 3 V. Comprehensive chemical analyses were conducted on all intermediate products, including the leachate, leach liquor, filtrate, solid precipitate, and the separated metal on the cathode. The outcomes of these analyses are meticulously presented in tables and graphs.

2

Ocena możliwości wykorzystania mieszanki osadowo-popiołowej do rekultywacji gruntów z uwzględnieniem wpływu pH środowiska na wymywalność metali ciężkich

Mizerna Kamila

Przemysł Chemiczny

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2023

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T. 102, nr 10

1087--1091

PL

Przedstawiono wyniki badań uwalniania metali ciężkich z mieszanki osadowo-popiołowej pod wpływem oddziaływania pH środowiska w szerokim zakresie wartości. Wyznaczono także stężenia metali ciężkich w podstawowym teście ługowania stosowanym w badaniu ziarnistych materiałów odpadowych. Wszystkie wyniki wymywalności porównano z zawartością całkowitą metali ciężkich w mieszance w celu oceny poziomu ich mobilności do środowiska gruntowo-wodnego. Proces wymywania metali ciężkich w dużej mierze zależy od faz mineralnych w odpadach oraz ich składu chemicznego, dlatego też parametry te były także przedmiotem analizy.

EN

Municipal sewage sludge and ashes from the combustion of solid fuels in households were mixed in a mass ratio of 1:1 on a dry basis, crushed and mineralized to det. the content of heavy metals. Grinded samples of the research material were stirred for 24 h in the leachant of various pH and the content of heavy metals in the obtained eluate was detd. using flame atomic absorption spectrometry. The leachability results were compared with the total content of heavy metals in the mixt. in order to assess the level of their mobility into the water environment. The pH of the environment strongly detd. the mobility of heavy metals.

3

Nickel recovery from low-grade laterites: study of thermal pre-treatments to improve the efficiency of the hydrometallurgical process

Borda Johana, Torres Robinson

Journal of Sustainable Mining

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2023

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Vol. 22. iss. 3

219--226

EN

The processing of lower-grade laterites to obtain nickel has increased due to the gradual depletion of higher-grade sulphide ore reserves. However, the extraction from laterites has been limited because conventional technologies imply a considerable expense of energy or reagents. In this document, the effect of thermal pre-treatments on a laterite sample is demonstrated to improve nickel leaching under moderate conditions. The influence of agents such as coke, coal and NaCl in the heat treatment was also studied. With the results it is presumed that part of the nickel occluded in the goethite migrates to the iron oxides surface during the heat treatment; this is why the dissolution of nickel is linked to that of iron. The highest extractions (64.7% nickel) were achieved by combining heat treatment and leaching with 1 M H2SO4 at ambient conditions. Compared to direct leaching of unpretreated laterite, leaching rates for this metal are increased by 26.5%. The chlorinating calcination and the optimization of the studied variables will be favourable to reach higher metallic extractions.

4

Recovery of Niobium Pentaoxide and Ammonium Sulfate from Titanium-Magnesium Production Waste

Ultarakova Almagul, Lokhova Nina, Karshyga Zaure, Toishybek Azamat, Yessengaziyev Azamat, Kassymzhanov Kaisar, Mukangaliyeva Arailym

Journal of Ecological Engineering

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2023

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Vol. 24, nr 11

227--235

EN

This study was aimed to investigate the development of a technology for the extraction of niobium pentaoxide and ammonium sulfate from titanium-magnesium production waste, specifically, the sublimates of dust chamber into concentrate in the form of niobium pentoxide. Optimal conditions for washing the niobium hydroxide precipitate by repulpation with hot (60–70°C) distilled water, drying at 200°C for 6 hours were determined. The influence of temperature and duration of the process was studied. Optimal conditions for the dynamic desorption of niobium from saturated ionite (Purolite A100) was determined. The results further indicated that the optimum quantity of the solution of desorption with sulfuric acid was equal to 5.5% and ammonium oxalate was equal to 4%, while temperature and the flow rate of the desorbing solution was 22–27°C and 6 rpm, respectively. The study of the precipitation of niobium from sulfuric acid desorbates showed that the interaction of niobium ions with ammonia takes place at a low rate. The degree of precipitation of niobium hydroxide equal to 99.6% was achieved in 7 hours of agitation of the suspension at a temperature of 22–25°C.

5

Wymywanie metali ciężkich z odpadów pobranych z hałdy wałbrzyskiej - badania wstępne

Zielińska Amelia

Górnictwo Odkrywkowe

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2023

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R. 64, nr 3

4--8

PL

Celem pracy było określenie wartości wymywania wybranych metali ciężkich z odpadów pochodzących z hałd wałbrzyskich. Próbki pobranych materiałów rozdrobniono na frakcje poniżej 4 oraz poniżej 1, które następnie poddano wymywaniu, a w powstałym eluacie oznaczono zawartość Cd, Cr, Cu, Ni, Pb, Zn. Wartości stężeń metali są poniżej granic oznaczalności. Na tej podstawie stwierdzono, że migracja metali ciężkich z odpadów pogórniczych do środowiska wodnego jest nieznaczna i nie powinna stanowić istotnego problemu. Badania wymagają jednak kontynuacji dla zróżnicowanych warunków wymywania.

EN

The aim of the work was to determine the leaching value of selected heavy metals from waste from Wałbrzych heaps. Samples of collected materials were crushed into fractions below 4 and below 1 mm, which were then subjected to leaching, and the content of Cd, Cr, Cu, Ni, Pb, Zn, was determined in the resulting eluates. Metal concentration values are below the limits of quantification. On this basis, it was found that the migration of heavy metals from post-mining waste to the aquatic environment is insignificant and should not be a relevant issue. However, research needs to be continued for different leaching conditions.

6

Rtęć w odpadach wydobywczych i możliwości ich zagospodarowania w wyrobiskach odkrywkowych województwa śląskiego

Klojzy-Karczmarczyk Beata, Mazurek Janusz, Staszczak Jarosław

Zeszyty Naukowe Instytutu Gospodarki Surowcami Mineralnymi i Energią PAN

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2022

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nr 110

129--141

PL

Wypełnianie wyrobisk odkrywkowych odpadami wydobywczymi jest możliwe w procesie rekultywacji technicznej, ale wymaga szczegółowego rozpoznania warunków środowiskowych. Zastosowanie różnego rodzaju odpadów do wypełniania wyrobisk jest zagadnieniem złożonym w zakresie jakości materiału odpadowego oraz w zakresie określenia lokalizacji miejsc przeznaczonych do takiego zagospodarowania odpadów. Istotne jest rozpoznanie lokalizacji czynnych wyrobisk odkrywkowych na tle granic głównych zbiorników wód podziemnych (GZWP) oraz w pobliżu cieków wodnych. Analizie poddano wyrobiska, w których eksploatowane są surowce węglanowe oraz wyrobiska piasków i żwirów. Analizy zostały wykonane w różnych latach aktywności wyrobisk ((Klojzy-Karczmarczyk i in. 2016a; Klojzy-Karczmarczyk i Staszczak 2017, 2019; Staszczak 2020). W grupie surowców węglanowych (kamienie łamane i bloczne), poza granicami GZWP oraz w odległości ponad 500 metrów od cieków powierzchniowych zlokalizowane są zaledwie 3 obiekty. W grupie piasków i żwirów, poza granicami GZWP oraz w odległości ponad 500 od cieków powierzchniowych znajduje się 19 obiektów. Zestawiono zawartość całkowitą rtęci oraz wielkość jej wymywania. Podano udział formy wymywalnej w całkowitej zawartości pierwiastka. Badania prowadzono w różnych warunkach pH środowiska. Analizę przeprowadzono na podstawie badań z lat 2014–2021 (Klojzy-Karczmarczyk i Mazurek 2014, 2019a, b, 2021). Odpady wydobywcze typu skała płonna (kruszywa) charakteryzują się wyższą zawartością rtęci całkowitej we frakcji najdrobniejszej i niższą we frakcjach grubszych. Udział formy wymywalnej rtęci w kruszywach jest na średnim poziomie 1,3–2,0%. Średni udział formy wymywalnej w mułach węglowych jest na poziomie 1,8%. Przy obniżaniu pH środowiska, udział ten wzrasta w każdym przypadku. Wyraźny wzrost wymywalności obserwuje się ponadto w odpadach zwietrzałych. Ze względu na jakość materiału odpadowego, badania odpadów wydobywczych wykazały możliwość ich zastosowania do celów rekultywacji.

EN

The open-cast workings filling with extractive waste is possible in the process of technical reclamation, but it requires a detailed recognition of environmental conditions. The use of various types of waste to fill the workings is a complex issue, in the field of the waste material quality and in the field of determining locations assigned for such waste management. It is important to recognise the location of active opencast mines against a background of main groundwater basins (MGB) and close to watercourses. The workings, left after extraction of carbonate raw materials, as well as sands and gravels, were analysed. The analysis were performed in different years of the open pits activity (Klojzy-Karczmarczyk et al. 2016a; Klojzy-Karczmarczyk and Staszczak 2017, 2019; Staszczak 2020). In the carbonate raw materials group (crushed and block stone) only 3 facilities are situated outside the MGB area and at a distance of more than 500 m from surface watercourses. In the sands and gravels group only 19 facilities are situated outside the MGB area and at a distance of more than 500 m from surface watercourses. Total mercury content and the amount of its leaching was compiled. The percentage of leachable form in the total content of the element was studied. The studies were carried out under various pH conditions of the environment. The analysis was based on the studies from 2014–2021 (Klojzy-Karczmarczyk and Mazurek 2014, 2019a, b, 2021). The extractive waste of the barren rock type (aggregate) features a higher content of total mercury in the finest fraction and a lower in coarser fractions. The share of mercury leachable form on average is 1.3–2.0%. The share of mercury leachable from coal sludge is approx. 1.8%. At pH reduction this share increases in each case. A clear increase in leachability is observed in the weathered waste. Because of the waste material quality, the studies on extractive waste have shown a possibility to use it for reclamation.

7

Study on the mechanism and kinetics of sulfuric acid leaching scandium from rich scandium anatase

He Fei, Gao Likun, Chen Long, Rao Bing, Shen Hairong, Peng Kebo, Gao Guangyan

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 3

art. no. 146171

EN

Scandium and its compounds have excellent properties, and are widely used in cutting-edge fields such as optics, electronics, and alloys. Thus, scandium is an important strategic metal. However, scandium is extremely sparsely distributed in the earth's crust, rarely occurs as an independent mineral, and requires a complex recovery process. Therefore, the study of the extraction of scandium is of great practical significance. This study examined the leaching test and kinetics of scandium under the acid leaching system of refractory anatase ore. Under appropriate two-stage countercurrent leaching conditions, the first stage of the particle size of fraction of -0.074 mm 82.6%, initial H2SO4 concentration of 6 mol/L, leaching temperature of 100 °C, acid/solid ratio of 3 ml/g, stirring speed of 300 rpm, and leaching time of 50 min; and the second stage of the initial H2SO4 concentration of 11 mol/L, leaching temperature of 150 °C, acid/solid ratio of 4 ml/g, stirring speed of 300 rpm, and leaching time of 50 min, a scandium leaching rate of 96.98% was achieved. The kinetics of scandium leaching conformed to a shrinking-core model, and sulfuric acid concentration and temperature were the most important parameters affecting the scandium leaching rate. The kinetic analysis of scandium leaching at different sulfuric acid concentrations showed that as the concentration increased, the sulfuric acid leaching of scandium changed from being chemical reaction-controlled to internal diffusion-controlled, and the apparent reaction order was 1.2429. The kinetics of scandium leaching at different temperatures showed that the sulfuric acid leaching of scandium was reaction-controlled and the apparent activation energy was 42.21 kJ-mol-1.

8

Recovery of pure palladium compound from the spent electroplating solutions by hydrometallurgical method

Nguyen Viet Nhan Hoa, Song Si Jeong, Lee Man Seung

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 1

88--100

EN

Electroplating of palladium (Pd) is practiced in the manufacture of electronic materials. The increasing demand for Pd metal necessitates the recovery of Pd(II) from the spent electroplating solutions. In this work, the recovery of Pd compound was studied from the cemented Pd by zinc (Zn) metal from spent electroplating solutions. Initially, the selective extraction ability of ionic liquids synthesized from commercial extractants for Pd(II) over Zn(II) from the synthetic HCl solution was investigated. Pd(II) was selectively extracted over Zn(II) from 9 M HCl solution by ALi-CY301(Nmethyl-N,N,N-trioctylammonium bis(2,4,4-trimethylpentyl) dithiophosphinic) and by ALi-I (N-methylN,N,N-trioctylammonium iodide) from weak HCl solution (pH 1). Since 9 M HCl was needed to completely dissolve Pd from the cemented Pd, ALi-CY301 was employed for the separation of Pd(II) and Zn(II) from the real HCl leaching solution of the cemented Pd. Two-stages counter-current extraction of the real HCl solution with ALi-CY301 resulted in selective extraction of Pd(II). Pd(II) was effectively stripped from the loaded ALi-CY301 by a mixture of HCl and NaClO. After oxidizing Pd(II) in the stripping solution to Pd(IV) by adding NaClO, Pd(IV) compound was synthesized by adding NH4Cl as a precipitant. By comparing leaching and extraction efficiency between hydrochloric and sulfuric acid solutions, a hydrometallurgical process consisted of HCl leaching, extraction with ALiCY301 and precipitation with NH4Cl was recommended for the recovery of pure (NH4)2PdCl6 from the cemented Pd.

9

Processing of Titanium-Magnesium Production Waste

Karshyga Zaure, Ultarakova Almagul, Lokhova Nina, Yessengaziyev Azamat, Kassymzhanov Kaisar

Journal of Ecological Engineering

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2022

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Vol. 23, nr 7

215--225

EN

The article presents the results of research on the processing of such wastes of titanium-magnesium production as sludge from sludge dumps and fine dump dusts from the electric smelting of ilmenite concentrates. The results of nitric acid leaching of sludge with the transfer of calcium into solution and the production of calcium nitrate are given. Titanium-containing cake after nitric acid leaching of sludge and electric smelting dust cannot be returned to the technological process due to its high silica content, so the silicon impurity was removed from their composition. Silicon removal was performed by fluoroammonium processing with sublimation of hexafluorosilicate compounds. An amorphous silicon dioxide product was obtained, after ammonia hydrolysis of silicon-containing sublimations and appropriate treatment of the sediment. The residue from the sublimation of silicon fluorides consists mainly of titanium-containing phases and can be suitable for return for electrofusion after ammonia treatment.

10

Copper Extraction from Complex Waste Dumps by Biochemical Leaching Method

Koizhanova Aigul, Magomedov David, Abdyldayev Nurgali, Kamalov Emil, Yerdenova Maria, Bakrayeva Akbota

Journal of Ecological Engineering

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2022

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Vol. 23, nr 10

283--290

EN

The article presents the research results for the effectiveness of copper extraction from ores of the Satpayev deposit with complex, mixed composition bacterial leaching. The experiments with pre-acidification of copper samples were performed using biological oxidation by A. Ferrooxidans bacterial culture, adapted strain. Biochemical opening moes of mineral raw materials using A. Ferrooxidans bacteria of a particular strain adapted to the copper waste composition and capable of oxidizing sulfide and iron-bearing minerals were worked out. The optimal growth conditions for microorganisms in copper mineral pulp medium were established (temperature, pH, S: L.) The highest leaching efficiency, up to 88.65%, was observed in the experiments with preliminary bio-oxidation of samples by A. Ferrooxidans bacterial culture.

11

Leaching of heavy metals from contaminated soil stabilised by Portland cement and slag Bremen

Lindh Per, Lemenkova Polina

Ecological Chemistry and Engineering. S

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2022

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Vol. 29, nr 4

537--552

EN

Leaching behaviour is an important evidence of soil quality. The assessment of leaching of heavy metals from the contaminated soil is vital for environmental applications. However, leaching may differ in soil stabilised by various ratios of binders. In this study we measured leaching behaviour of soil contaminated by As, Cd, Co, Cr, Cu, Hg, Ni, Pb, V, Zn, methyl Hg, aliphatic compounds of hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and dissolved organic carbon (DOC). To evaluate leaching of these substances we tested the effects of changed amount of binder (120 kg and 150 kg) and binder ratios (70/30 %, 50/50 % and 30/70 %) added to soil samples. Soil was dredged from several stations in Ostrand area, SCA Sundsvall Ortvikens Pappersbruk. The results demonstrated a systematically decreasing leaching with the increased slag. The contribution of this research include: (i) devising systematic approach to extract information on leaching from stabilised soil collected from the coastal area of Bothnian Bay, (ii) developing a workflow for stabilising soils by various combination of Portland cement Basement CEM II/A-V (SS EN 197-1) and ground granulated blast furnace slag (GGBFS), Bremen type (SS EN 15167-1), (iii) determining water ratio and density for the untreated and stabilised soil and performing comparative analysis, (iv) evaluating chemical content of pollutants and toxic elements in the aggregated soil samples. Treatment of the contaminated soil by binders improved its parameters by the increased strength and decreased leaching of heavy metals and toxic elements.

12

Environmental monitoring to assess ground water quality and its impact on soils in southwestern India

Sandhu Randhir Singh, Sehgal Simerpreet Kaur, Amrit Kumar, Singh Navdeep, Singh Didar

Acta Geophysica

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2022

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Vol. 70, no 1

349--360

EN

The present study attempts to investigate physicochemical features and evaluate quality of collected ground water samples from benchmark locations in Fazilka district, southwestern (SW) side of the Punjab. The samples of groundwater (GW) as well as soil were collected from different locations and examined for pH, electrical conductivity (EC), carbonates (CO3 2 ), bicarbonates (HCO3 −), chlorides (Cl−), magnesium (Mg2+), calcium (Ca2+), sodium (Na+), sulfate (SO42−) and potassium (K+). The appropriateness of water for drinking was checked using water quality index (WQI), while indices like soluble sodium percentage (SSP), sodium adsorption ratio (SAR), residual sodium carbonate, magnesium hazard, permeability index and Kelly’s ratio were investigated for appraisal of irrigation water quality. Samples are statistically tested using two-way ANOVA and principal component analysis (PCA) to extract correlation between water parameters. Most of the samples were under high to low (C3S1), high to medium (C3S2) and very high to high (C4S3) based on US Salinity Laboratory (USSL). On the base of RSC, samples were under safe to unsuitable category. For hydrochemistry analysis, the piper diagram indicates that water samples were mixed type and Ca-Mg-HCO3 type. Study indicated that water with high salinity was used for irrigation of crops and it has adverse effects on the soil quality and crop yield is of concern for future.

13

Leaching of coal by trioxoboric acid for coal clearing

Bilgin Oyku, Hacıfazlıoğlu Hasan, Sert Dilara

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 5

129--136

EN

Trioxoboric acid (H3BO3) is a white weakly soluble acid produced from boron minerals. This acid type was used for the first time in this study for ash and sulfur removal from coal. Ash and sulfur are the most important impurities in the content of coal and have significant effects on environmental pollution. It is possible to remove ash and sulfur by H3BO3 leaching. However, there have not been enough studies in this area and the performance of trioxoboric acid has not been fully demonstrated. In this study, leaching performance of trioxoboric acid and other strong acids (hydrofluoric, hydrochloric and sulfuric acids) has been demonstrated. Trioxoboric acid removed ash and sulfur from coal by 41.18% and 32.16%, respectively. This acid can compete especially with hydrochloric and sulfuric acid in sulfur removal. However, hydrofluoric acid provided the best results in ash and sulfur removal.

14

Hydrometallurgical recovery of platinum group metals from spent automotive converters

Rzelewska-Piekut Martyna, Paukszta Dominik, Regel-Rosocka Magdalena

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 2

83--94

EN

This work presents studies on the recovery of platinum group metals (PGM), especially platinum and rhodium, from spent automotive converters using hydrometallurgical techniques such as leaching and liquid-liquid extraction. The XRD analysis confirmed the presence of indialite – the high temperature hexagonal form of cordierite (the main catalyst building material) in the solid samples. The influence of time and temperature on the leaching of PGM from spent automotive converters was investigated. The largest amounts of Pt(IV) and Rh(III) were leached with freshly prepared aqua regia and a mixture of HCl, HSO₄, and H₂O₂. Further, liquid-liquid extraction with quaternary phosphonium ionic liquid (Cyphos IL 101) was applied to recover PGM from the leach solutions (after leaching with a mixture of HCl, H₂SO₄, and H₂O₂) and to separate Pt(IV) from Rh(III).

15

Exploitation of spent nickel-metal hydride (Ni-MH) batteries as a source of value-added products

Farghal Fatma E., Abdel-Khalek Mohamed A.

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 6

95--101

EN

Spent Nickel–metal hydride batteries can be sources of valuable metals such as nickel, cobalt, manganese, rare earths and toxic chemicals. The recycling of these materials is necessary from both economic and environmental points of view. In this study the nickel is leached in acid solution followed by precipitation and thermal decomposition or by cementation. The affecting parameters such as acid type and concentration, time, temperature and solid/liquid ratio were investigated. The maximum of leached nickel could be obtained in 3M sulfuric acid at 65°C for 60 min with solid-to-liquid ratio of 30 g L-1. The liquid film is a more suitable model for demonstrating the kinetics of the nickel leaching. Thermal decomposition of the precipitated nickel dimethyl-glyoxime was employed in preparation of nickel oxide. Nickel was separated from aqueous solution by cementation on zinc. The cementation process follows pseudo first-order kinetics and diffusion controlling steps. The yield was 91% of the original nickel content.

16

Fate of Tebuconazole in Polish Mineral Soils – Results of Simulations with FOCUS PELMO

Siek Marcin Maciej, Paszko Tadeusz

Journal of Ecological Engineering

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2021

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Vol. 22, nr 11

131--141

EN

The degradation of tebuconazole in the majority of Polish mineral soils withlow organic carbon content is slow, and its adsorptionis especially low in subsoils. Therefore, the fate of tebuconazole in these soils cannot be predicted based on the results of the adsorption and degradation experiments carried out in typical soils of the European Union. For this reason, the simulations of tebuconazole accumulation in Polish soils and its leaching to groundwater were carried out. The cultivation of winter cereals and winter oilseed rape was simulatedusing FOCUS PELMO in six Arenosol, Luvisol, and Chernozem profiles, representing 59% of Polish arable mineral soils.The simulations indicated that almost all fungicide that reached the soil surface was retained in the topsoil layer of 0–15 cm. The highest concentrations (range of 0.069–0.320 mg/kg) were estimated for the layer 0–5 cm. The results suggested that runoff can be the principal source of tebuconazole in surface water. It was found that the majority of tebuconazole that reached the soils was microbiologically degraded. However, in the years with unfavorable weather conditions for degradation, up to 11% of the tebuconazole that reached the soils remain undegraded. In addition to the accumulation of tebuconazole in the topsoils, the simulations indicated its very slow but constant penetration into the subsoils. The estimated concentrations of tebuconazole in percolate water were low: < 0.02 μg/L at the depth of 25 cm, < 0.002 μg/L at the depth of 75 cm, and trace concentrations at the depth of 1 m in one profile. The obtained results were consistent with the results of the monitoring studies available in literature.

17

Leachability of heavy metals from autoclaved fly ash-lime building bricks

Tanriverdi Mehmet, Şen Gul Akar, Cicek Tayfun, Şen Sezai, Onel Oznur

Inżynieria Mineralna

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2021

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no. 1

67--74

EN

The fly ash as a byproduct of coal-fired power plants constitutes vital ecological problems. In Turkey, approximately 15 million tons of ashes are generated via the combustion of 40 million tons of lignite yearly. Worldwide, a number of investigation and applications were undertaken to utilize fly ash in order to overcome the environmental problems. One of the application area of fly ashes is the production of building bricks. Characterization of fly ash samples from Seyitomer and Yatagan coal-firing power plants were conducted in this study. TCLP 1311, ASTM3987-85 and EN 12457-2 leaching tests on the cylindrical fly ash/lime brick (FA/LB) samples which were produced from Seyitomer and Yatagan thermal power plant fly ash-lime mixtures were performed to determine the leachability of some chosen trace elements. e results show that the release of all trace elements was lower than the hazardous material limit values of waste acceptance. us, non- fired fly ash bricks are an advantageous way to solving environmental effect of disposal of fly ashes.

PL

Popiół lotny jako uboczny produkt spalania w elektrowniach węglowych stanowi istotny problem ekologiczny. W Turcji w wyniku spalania 40 mln ton węgla brunatnego rocznie powstaje około 15 mln ton popiołów. Na całym świecie podjęto szereg badań w celu wykorzystania popiołu lotnego w celu przezwyciężenia problemów środowiskowych. Jednym z obszarów zastosowania popiołów lotnych jest produkcja cegieł budowlanych. W pracy przedstawiono wyniki badania charakterystyki próbek popiołu lotnego z elektrowni węglowych Seyitomer i Yatagan. Przeprowadzono testy ługowania wybranych pierwiastków śladowych, zgodnie z normami TCLP 1311, ASTM3987-85 i EN 12457-2 na cylindrycznych próbkach popiołu lotnego/ cegieł wapiennych (FA / LB), które zostały wyprodukowane z mieszanek popiołu lotnego i wapna w elektrowniach Seyitomer i Yatagan. Wyniki pokazują, że uwalnianie wszystkich pierwiastków śladowych było niższe niż dopuszczalne wartości dla materiałów niebezpiecznych. Zatem niewypalane cegły z popiołu lotnego są korzystnym sposobem rozwiązania problemu środowiskowego wpływu usuwania popiołów lotnych.

18

Evaluation of different binder combinations of cement, slag and ckd for s/s treatment of tbt contaminated sediments

Lindh Per, Lemenkova Polina

Acta Mechanica et Automatica

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2021

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Vol. 15, no. 4

236--248

EN

The seabed in the ports needs to be regularly cleaned from the marine sediments for safe navigation. Sediments contaminated by tributyltin (TBT) are environmentally harmful and require treatment before recycling. Treatment methods include leaching, stabilisation and solidification to remove toxic chemicals from the sediments and improve their strength for reuse in the construction works. This study evaluated the effects of adding three different binder components (cement, cement kiln dust (CKD) and slag) to treat sediment samples collected in the port of Gothenburg. The goal of this study is to assess the leaching of TBT from the dredged marine sediments contaminated by TBT. The various methods employed for the treatment of sediments include the application of varied ratios of binders. The project has been performed by the Swedish Geotechnical Institute (SGI) on behalf of the Cementa (HeidelbergCement Group) and Cowi Consulting Group, within the framework of the Arendal project. An experiment has been designed to evaluate the effects of adding CKD while reducing cement and slag for sediment treatment. Methods that have been adopted include laboratory processing of samples for leaching using different binder combinations, followed by statistical data processing and graphical plotting. The results of the experiment on leaching of TBT for all samples are tested with a varied ratio of cement, slag, CKD and water. Specimens with added binders 'cement/CKD' have demonstrated higher leaching compared to the ratio 'cement/slag/CKD' and 'cement/slag'. The 'CKD/slag' ratio has presented the best results followed by the ‘cement/slag/CKD’, and can be used as an effective method of s/s treatment of the sediments. The results have shown that the replacement of cement and slag by CKD is effective at TBT leaching for the treatment of toxic marine sediments contaminated by TBT.

19

Selective leaching of copper from near infrared sensor-based preconcentrated copper ores

Ambo Amos Idzi, Iyakwari Shekwonyadu, Glass Hylke J

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 1

204--218

EN

Copper oxide ore was pre-concentrated using near infrared sensor-based method and classified as product, middling and waste. The product and middling fractions were leached with ammonium chloride reagent. The effect of temperature, ammonium chloride concentration, solid- liquid ratio, stirring speed and particle size experimental variables were investigated. Mineralogical and chemical analysis of the ore fractions indicated that copper content was in accordance with the preconcentration strategy, with the product having a higher concentration than the middling and waste. The rate of copper extraction was found to be higher in the product than in the middling sample which further supports the near infrared classification, QEMSCAN®, X-ray diffraction, SEM mineralogical and X-ray florescence and Inductively coupled plasma Mass spectrometry chemical data. It was revealed that the leaching rate increases with increasing ammonium chloride concentration, temperature and decreasing ore particle size, stirring speed and solid-liquid ratio. Analysis of the experimental data by shrinking core model indicated that the dissolution kinetics follow the heterogeneous reaction model for the chemical control mechanism where the activation energies of 45.9 kJ/mol and 47.5 kJ/mol for product and middling fractions respectively were obtained. Characterization of the residue obtained at optimum leaching condition with X-ray diffraction suggests that copper was selectively leached when compared to the profile of the raw ore. The trace levels of metals associated with abundant X-ray diffraction profiles of residue found in the leachate further confirm the selective leaching process.

20

Jiroft refractory manganese ore leaching using oxalic acid as reducing agent in sulfuric acid solution

Sobouti Arash, Shafaat Niosha, Abdollahzadeh Ali A.

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 2

374--385

EN

Leaching process of Jiroft refractory manganese ore was investigated. The effects of operating parameters such as liquid to solid ratio, pulp temperature, sulfuric acid concentration, and oxalic acid concentration were studied and the optimization was done through the response surface methodology (RSM) based on central composite design (CCD) model. The recoveries of Mn, Fe and Si were selected as response of design. The optimum condition was determined by ANOVA, indicating that the liquid to solid ratio, oxalic acid concentration and pulp temperature for Mn recovery and liquid to solid ratio, pulp temperature and sulfuric acid concentration for Fe recovery and liquid to solid ratio for Si recovery were the most effective parameters, respectively. Under the optimum conditions of liquid to solid ratio= 11.8%, pulp temperature= 70 ℃ sulfuric acid concentration= 40 g/L and oxalic acid concentration= 35 g/L, 71.1%, 4.67% and 0.6% of Mn, Fe and Si were recovered, respectively.