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1

Recovery of rare earths and lithium from rare earth molten salt electrolytic slag by lime transformation, co-leaching and stepwise precipitation

Li Xinglan, Luo Peidi, Liu Zishuai, Tang Xuekun, Zhang Baqun, Guo Jiangfeng

Physicochemical Problems of Mineral Processing

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2024

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Vol. 60, iss. 2

art. no. 186333

EN

The rare earth molten salt electrolytic slag (REMSES) has recently attracted significant attention due to its potential environmental hazards and high content of rare earths and lithium, leading to a surge in recycling efforts. In this study, we propose and demonstrate a novel and straightforward process for the simultaneous extraction of rare earths and lithium from REMSES through lime transformation and sulfuric acid leaching at low temperatures. Firstly, during the lime transformation process, REMSES is converted into hydroxides that can be easily dissolved in acids. Secondly, REEs and Li present in the slag are co-extracted using a conditional sulfuric acid leaching method, resulting in 95.72% REEs leaching efficiency and 99.41% Li leaching efficiency under optimal conditions. Finally, REEs and Li in the solution are precipitated using oxalic acid and trisodium phosphate with precipitation efficiencies of 99.02% for REEs and 94.85% for Li respectively. This innovative process enables the conversion of REEs and lithium from REMSES into high-purity products (a mixture of REOs with 99.31% purity; Li3PO4 with 98.93% purity), thereby facilitating their valuable utilization.

2

Characterization of the effects of acetic acid on the recovery of valuable contents from flotation tailings of non-sulfide metals

Yoğurtcuoğlu Emine

Physicochemical Problems of Mineral Processing

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2024

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Vol. 60, iss. 1

art. no. 185168

EN

Non-sulfide lead flotation tailings draw attention in terms of their valuable contents. Dissolution studies have been carried out with strong inorganic acids, especially in ore form, but these acids have been unfavorable in removal in the context of metal recovery processes. Organic acids, on the other hand, are notable for their environmentally friendly properties and selective metal recovery opportunities. In this study, the effects of acetic acid on metal recovery from oxidized waste were investigated with different experimental parameters at a laboratory scale. Optimal conditions were determined depending on the increase in acetic acid concentration. At 0.75-1.0 M acid concentrations, 49-55% Pb and 49-54% Zn recovery efficiencies were obtained with grades of 7.0-7.2% and 19.5-19.7%, respectively. The recovery of Pb/Zn by the leaching process with acetic acid and the selective nonrecovery of iron were also observed through characterization studies. With the Rietveld XRD method, an increase in iron minerals such as goethite and a decrease in smithsonite-hydrozincite minerals were determined. These changes were seen as a decrease in the contents of these minerals in SEM/EDX analysis and as a decrease in smithsonite mineral bond structures in the FT-IR analysis. This study showed that acetic acid has many advantages in the utilization of zinc-lead-containing oxide flotation tailings, which have high economic value, such as selective metal recovery, easy biodegradability, environmental friendliness, and non-corrosiveness.

3

Characterization and concentration of U, Nb, Pb, Ag, and Fe from the Huayangchuan polymetallic ore

Cheng Hongwei, Lv Zihu, Wu Dongyin, Zhao Dengkui

Physicochemical Problems of Mineral Processing

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2024

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Vol. 60, iss. 2

art. no. 188070

EN

The separation and recovery of valuable metals from the Huayangchuan uranium polymetallic ore was investigated based on mineralogical research and mineral processing experiments. The most promising valuable elements in the ore, according to mineralogical studies, are U, Nb, and Pb. 95.75% of U and 93.00% of Nb are found in betafite, 46.85% of Pb is present in galena, 52.01% of Pb occurs in cerussite, and associated Ag exists primarily in galena. The beneficiation process involving gravity concentration, magnetic separation, and flotation was determined based on the mineralogical characteristics of the ore. The U-Nb concentrate with U grade of 3578 ppm and recovery of 83.18 %, Nb2O5 grade of 4391 ppm and recovery of 74.55 % can be obtained, and five elements including U, Nb, Pb, Ag, and Fe are recovered. Compared with the previous beneficiation experimental process, the flowsheet is greatly simplified and the beneficiation recovery efficiency has been improved. The results of this investigation can help to address the gaps in the processing of low-grade uranium deposits with similar mineralogical properties.

4

Exploration and characterization of barite mineral from Azara-Nassarawa ore deposits from suitabiity in industrial applications

Nzeh Nnaemeka Stanislaus, Popoola Patricia Abimbola

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 2

art. no. 166104

EN

Primary concentrations of Azara barite deposit in Nassarawa state, Nigeria were conducted; employing simplified gravity concentration techniques. Particle size distribution, specific gravity, physicochemical and morphological analyses of the sample was conducted. These analyses were done in order to establish process efficacy and effectiveness of gravity concentration processes for recovery of barium from the ore deposit, as well as its suitability in various industrial applications, such as the oil and gas sectors. Thus, microstructural, chemical composition and certain physicochemical characteristics/properties of the mineral sample of Azara-Nassarawa barite were determined. XRD, XRF, SEM and EDS analyses were utilized in determining morphology as well as quantitative and qualitative chemical analyses of the sample. Barite sample with average particle size of -355+150μm was subjected to concentration, adopting jigging and tabling gravity separation as the concentration methods. Hitherto, based on quantitative and qualitative chemical analyses conducted, the sample was composed of about 36.2% BaO and 40.5% Ba, respectively; and also possessed an average specific gravity (SG) of about 3.85. Further, the qualitative analysis of the mineral products of jiggling and tabling indicated that jigging had a concentrate recovery of 130.98% Ba with SG increase of 11.2% while tabling had 89.81% Ba recovery with 8.6% SG increase. Assay and SG results confirm gravity concentration efficiency and thus, establish the barite from Azara-Nassarawa ore deposits suitable for certain industrial applications. This will serve as a tool and a step further towards mitigating existing problems or challenges in mineral concentration and processing of such deposits for industrial purposes.

5

Eti Copper Siirt flotation plant revision studies

Kara Yaşar, Tatar Ali, Hasyamanlar Ahmet

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 5

art. no. 166260

EN

Several optimization studies were made to increase metal recovery and reduce operational costs of the concentrator in Siirt Madenköy copper mine. In consequence of these studies, effects of the changes in operating parameters, cost and plant recovery will be examined at this article. In this article, we will discuss two important revision studies, which are (i) replacement of 500 mm hydrocyclone set used in ball mills with 350 mm of hydrocyclone set, (ii) replacing the present Ball Mill with a SAG mill. Correspondingly elimination of the crushing and screening plant, (iii) increasing the scavenger cells from 4 to 6 by the addition of 2 more cells. In consequence with this feeding the middling tail to the increased scavenger cells which was treated as a part of final tail before this change. We will examine the effect of all these changes to the final recovery, concentrate grade and final cost.

6

Exploring the characterization, liberation and flotation response of a Nigerian low-grade copper ore

Nheta Willie, Ola-Omole Omoyemi O.

Journal of Sustainable Mining

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2023

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Vol. 22, iss. 1

20--32

EN

This study explores the characterization, liberation and flotation response of low-grade copper ore from Anka area, Zamfara state Nigeria. The ore was crushed, milled and sieved in accordance with BS 410 standard. It was characterized with XRD, XRF, SEM-EDS and AAS. Froth flotation was carried out with varying %solids, pH, retention time and collector dosages using SEX and sodium oleate. Particle size distribution of the ore shows its economic liberation between -150 and +106 µm while 80% passing corresponds to 175.7 µm using the Gaudin Schuhmann equation. However, according to metallurgical balance calculation, 63 µm proved to have the highest metal content. Identified peaks of the copper ore by XRD revealed the presence of pyrite and chalcopyrite as the major mineral content at 47 and 36%, respectively, while other elements were present in traces. XRF shows Fe and Cu as the major elements and others in traces. Morphology, according to SEM-EDS, revealed that Fe is the major impurity while the presence of Cu and S confirmed chalcopyrite is present in the ore minerals. AAS shows an average of 25.87% Cu and 32% Fe in the ore. Optimum recoveries of copper were recorded at 30% solids, pH of 8, 30 minutes retention time. The highest recovery of 95.94% was recorded with SEX at 0.25 mol/dm3, while recoveries were lower with PAX, the highest recovery being 33% at 0.20 mol/dm3. 0.25 mol/dm3 of SEX recorded the highest yield and enrichment ratio of 40.38 and 2.38, respectively.

7

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

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2023

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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%.

8

Analiza rynku złota – wybrane aspekty

Kowal Barbara, Prusak Szymon, Pokusa Przemysław

Inżynieria Mineralna

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2023

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no. 2, vol. 2

37--43

PL

Szczególnie cennymi surowcami mineralnymi są metale i kamienie szlachetne. Do metali szlachetnych zalicza się złoto, srebro i platyna, natomiast w grupie kamieni szlachetnych są m.in. diamenty, rubiny, szmaragdy, szafiry i wiele innych. Złoto jako kopalina nie odgrywa istotnego znaczenia gospodarczego, a jako metal jest mało użyteczne. Jednak od dawna stanowi symbol władzy, bogactwa i bezpieczeństwa. Ta symbolika stanowi podstawę wartości tego kruszcu. Artykuł stanowi omówienie wybranych aspektów rynku złota. Przedstawia informacje na temat pochodzenia złota i lokalizację miejsc z największymi złożami złota na świecie. Przybliża największych producentów złota oraz czołowe kopalnie, w których poziom wydobycia stanowi prawie 12% globalnego wydobycia złota. Prezentuje możliwe kierunki wykorzystania złota, które znajduje zastosowanie głównie w branży jubilerskiej, w stomatologii oraz jako inwestycja. Dodatkowo przedstawiono społeczny i przyrodniczy aspekt wydobycia złota. Autorzy zwracają szczególną uwagę na nielegalne „kopalnie”, którym obce są działania fair trade i których działalność degraduje ogromną skalę terenów lasów deszczowych.

EN

Metals and precious stones are precious mineral raw materials. Precious metals include gold, silver, and platinum, while the group of precious stones includes, among others: diamonds, rubies, emeralds, sapphires, and many others. Gold as a mineral has no significant economic importance and as a metal, it is of little use. However, it has long been a symbol of power, wealth, and security. This symbolism is the basis of the value of this precious metal. The article discusses selected aspects of the gold market. It presents information on the origin of gold and the location of places with the largest gold deposits in the world. It presents the largest gold producers and leading mines, where the level of extraction accounts for almost 12% of global gold mining. It presents possible directions for the use of gold, which is used mainly in the jewelry industry, in dentistry, and as an investment. Additionally, the social and natural aspects of gold mining were presented. The authors pay particular attention to illegal "mines" that do not comply with fair trade activities and whose activities degrade a large scale of rainforest areas.

9

A Study on the Recovery of Zinc and Pig Iron from Byproducts after Steelmaking Dust Treatment

Wang Jei-Pl

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 1

205--208

EN

In this study, a research was conducted to recover metallic zinc and pig iron and to improve the purity and the recovery rate through a reduction process for zinc and iron in the byproducts that are generated after steelmaking dust treatment. As the result of the calcination, it was confirmed that Cl (6.06%) and K (3.37%) decreased to Cl (2.75%) and K (0.22%), respectively. For the zinc powder that was recovered with reaction temperature of 1100°C, reaction time of 4 hours, and argon gas of 1L/min as the optimal conditions. The measurement for the purity of zinc was 99.8% and the recovery rate was 92.14%. The melt reduction for recovering pig iron from the residue was reacted under reaction temperature of 1600°C, flux composition (CaO:SiO2) of 1:1, and reducing agent infusion ratio (residue: C) of 14:1, and the pig iron was measured to have a purity of 87.7% and a recovery rate of 91.81%.

10

Assessment of Removal of Fines from Reclaimed Asphalt Binder Using Fourier Transform Infrared Spectroscopy

Dare Pranoti Deepak, Hedaoo Namdeo

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 4

79--88

EN

The natural environment is suffering greatly from population growth, industrialization, and waste production. When pavements are to be repaired or reconstructed, the waste material poses a threat as it is landfilled and not used up to its potential. Reclaimed asphalt pavement (RAP) has been gaining importance as there is a depletion of natural resources as well as its potential to perform well if reused or recycled. The extraction and recovery process is carried out to evaluate the properties of the aged binder in RAP. Extraction and recovery need to be coupled with gravitational sedimentation and filtration for the removal of mineral fillers from the aged binder + solvent solution. This study uses Centrifuge extraction and a rotary evaporator for extraction and recovery, respectively. In this study, three different solvents, namely tri-chloroethylene (TCE), toluene, and n-propyl bromide (nPB) are used for the centrifuge extraction. Extraction was followed by gravitational sedimentation and filtration. The results were evaluated by Fourier Transform Infrared spectroscopy (FTIR). Gravitational sedimentation is carried out and samples are tested after 0, 30, 60, 120, 240, and 1440 min by FTIR followed by filtration. In order to assess the properties of aged binder accurately, it should be free from mineral fines. Based on the properties of aged asphalt, percentages of RAP binder and rejuvenator by virgin binder can be evaluated. The results demonstrated that the removal efficiencies were affected by the type of solvent used for extraction.

11

World experience in the use of excess sewage sludge

Jumasheva Kamshat, Syrlybekkyzy Samal, Serikbayeva Akmaral, Nurbayeva Farida, Kolesnikov Alexandr, Bessimbayeva Zhanar, Uisimbayeva Zhanar

Acta Innovations

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2023

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no. 50

18--28

EN

The world experience of neutralization and disposal of excess sludge of urban sewage is considered. The sludge generated during the technical treatment of municipal wastewater is dangerous, has low dehydration, the percentage of moisture is more than 96%, contains some pathogenic and organic substances, as well as heavy metals. In the Mangystau region of Aktau (Kazakhstan) at a sewage treatment plant, sewage sludge is mainly accumulated on silt sites after minimal treatment. The main directions of neutralization and disposal of excess sludge used in Asian and European countries are generalized. For example, while authors from China conducted research on ultrasonic chemical treatment of urban sludge and drying by artificial methods, authors from Europe paid more attention to the disposal of excess sludge from municipal wastewater, in the form of road Surface additives, cement strength additives or modified bentonite for further use. Sewage sludge as a safe fertilizer in the national economy. Their advantages and disadvantages are shown, considering environmental and economic efficiency. The advantages of many studies can be indicated by the efficiency of the secondary use of sewage sludge, as well as a significant reduction in the area allocated for the storage of precipitation data. The disadvantages of these studies can indicate significant economic and time costs, which are ultimately compensated by the positive results of their secondary use.

12

Recycling of Polyethylene Terephthalate (PET) Bottles in the Logistics Supply Chain – Overview

Zając Paweł, Ejdys Stanisław, Dzik Renata

Rocznik Ochrona Środowiska

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2022

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Tom 24

439--456

EN

A great deal of packaging made of PET is observed in logistics supply chains, and the article is mainly concerned with food – bottles. Implementing the EU’s “zero-waste” guidelines implies action on the part of producers of packaging and food for B2C distribution to find new solutions to enable the above-mentioned stakeholders in the logistics supply chain to balance the business mentioned above parties – taking into account environmental protection. The article discusses the tasks and possibilities under the above conditions of a new type of “RECYCLER” companies, which, at the end of the life of PET packaging, i.e. after the foodstuffs in PET bottles have been consumed, produce a recyclate and return it to reproduction. In several journals, including, e.g. (Połednik et al. 2016, Topiarzová et al. 2011), respecting good recycling practices – there is an ongoing discussion on the sense of introducing reusable packaging, deposits, etc. This article discusses the barriers to recovery in a multi-level plastics recovery system, with specific reference to the operation of a PET bottle recycling line, and presents a pre-verified concept for a method to increase the efficiency of separating PET bottles from the plastics fraction in a multi-level waste separation system.

13

LCD panels bioleaching with pure and mixed culture of Acidithiobacillus

Willner Joanna, Fornalczyk Agnieszka, Saternus Mariola, Sedlakova-Kadukova Jana, Gajda Bernadeta

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 1

15--23

EN

The influence of pure and mixed culture of A. ferrooxidans and A. tiooxidans as well as different pulp density (1 and 2%) of LCD panels on the In and Sn bioleaching efficiency was investigated. Pulp density is one of the factors affecting the metals extraction efficiency during biological leaching. It has been shown that lower pulp density results in higher indium and tin dissolution. The A. ferrooxidans bioleaching system showed better metal extraction results than A. thiooxidans, especially for tin, indicating the special role of iron and A. ferrooxidans in tin recovery. The highest leaching rate of both indium (94.7%) and tin (98.2%) was obtained using iron and sulfur medium inoculated with mixed bacteria and a pulp density of 1% w/v.

14

Estimation of grade and recovery in the concentration of barite tailings by the flotation using the MLR and ANN analyses

Deniz Vedat, Umucu Yakup, Deniz Orcun T.

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 5

art. no. 150646

EN

This study aimed to find optimal models in a comparative framework to estimate the recovery and grade of barite concentrate obtained from the rougher flotation of the barite tailings. Therefore, firstly, the effect of four operating parameters (flotation time, pH, collector dosage, and depressant dosage) on the rougher flotation of the barite tailings containing 37.23% BaSO4 was experimentally investigated. Secondly, two models called the multivariable linear regression (MLR) and the artificial neural network (ANN) were used for the estimation of the recovery and grade of the barite concentrate for the rougher flotation optimization. The R2 values found from the MLR and ANN models were 0.828 and 0.995 for the concentrate recovery, and 0.977 and 0.960 for the barite concentrate grade, respectively. In the comparison of the models determined, it was found that the ANN model expressed quite well than the MLR models, especially for the recovery of the rougher concentrate.

15

Beneficiation and concentration of feldspar from syenite ore in Medina, Saudi Arabia for industrial utilization

Gougazeh Mousa

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 6

art. no. 155056

EN

The objective of this study was to reduce the contents of iron and titanium heavy minerals of feldspar from Medina syenite ore by a combination of magnetic separation and flotation to obtain the commercial scale of feldspar concentrate for glass and ceramics industries. For the first time, a process flowchart was provided in the light of this study to produce a high-quality K-feldspar product from syenite ore, which meets the requirements of feldspar for glass and ceramics productions. The results reflect that the best performance separation of iron and titanium contents was produced by a dry magnetic separator at 16.000 gauss. The produced feldspar concentrate by magnetic separation yielding 0.54% Fe2O3 with 87% Fe2O3 recovery and 0.57% TiO2 with 16% recovery. The flotation tests were performed on the non-magnetic fraction of the syenite ore. In this stage, the most effective for removal of Fe2O3 and TiO2 from syenite ore was obtained at a 300 g/ton dosage of a mixture of Aeromine 3030C and Aeromine 801 + Aeromine 825 as a collector in an acidic medium (pH 3). The final feldspar concentrate with 0.07% Fe2O3 and 0.06%TiO2 grades was obtained with 89% Fe2O3 recovery and 86% TiO2 recovery. The commercial scale of feldspar concentrate from syenite ore can meet the desired specification of grades 1 and 2 for glass, porcelain, and ceramics industries.

16

Assessing benthic macroinvertebrates in relations to environmental variables and revitalisation works

Czerniawska-Kusza Izabela

Ecological Chemistry and Engineering. S

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2022

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Vol. 29, nr 1

99--110

EN

Macroinvertebrates of two ex-manor ponds located in Chroscina, Opole Region (Poland) were studied from 2015 to 2018 to investigate their community composition and diversity and evaluate the heterogeneity of communities on spatial and temporal scale referring to environmental variables and revitalisation work. A total of 32 taxa were recorded (at the family level, except Oligochaeta), 13 of which were Ephemeroptera, Odonata and Trichoptera, recognised as sensitive groups in lentic ecosystems. Macroinvertebrate richness and diversity varied considerably, especially in spring and summer. It was found that habitat heterogeneity influenced benthic invertebrates more than basic water parameters. However, the environmental variables together accounted for only 38 % of the observed variations. Thus, other factors, such as fish predation, may have played a leading role in community shaping. The distinct differences between pond communities, four years after the revitalisation works, resulted more from different habitat features than from the previous sediment removal.

17

State of the Art in the End-of-Life Vehicle Recycling

Lenort Radim, Staš David, Wicher Pavel, Straka Martin

Rocznik Ochrona Środowiska

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2021

|

Tom 23

902--913

EN

Growing ecological awareness in society and legal regulations aimed at reducing the negative impact of used products on the environment means that waste management begins to play a significant role in the modern world. Therefore, it is necessary to conduct research towards the organization and implementation of waste management. It has been noticed that an important link in the economy is the recycling of used products. Thus, numerous studies are undertaken in the direction of organization, improvement, automation and computerization of the product and material recycling process. The article presents the results of literature research in terms of the implementation of the end-of-life vehicle recycling process.

18

Investigation of the frother effect in two and three phases systems on bubble size, surface tension, recovery and grade in chalcopyrite flotation

Ceylan Adnan, Bulut Gülay

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 6

23--35

EN

In this study, the effect of frother was investigated in two and three phases in the systems of the flotation. While the two-phase system consisted of liquid and gas, the three-phase systems contained a chalcopyrite ore. The study of three-phase systems was performed with the ore on a laboratory and plant scale. Effect of the amount and type of the frothers, their mixtures, and pH were examined depending on the bubble size, grade of the concentrate, and the recovery of chalcopyrite flotation. The results showed that as the amount of frothers increased, there was a reduction in the bubble size in all experiments. Additionally, the frother mixtures gave a positive effect on the chalcopyrite flotation. One of the most important purposes of flotation frothers shrinks the air bubble. As can be understood from the tests this time reduction of the frothers bubble size has a positive effect on the flotation. Likewise, it increases the foam stable value. It is observed from this study that increasing the amount of frothers decreases the surface tension and bubble size at different pH.

19

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).

20

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.