scholarly journals Towards Understanding the Cathode Process Mechanism and Kinetics in Molten LiF–AlF3 during the Treatment of Spent Pt/Al2O3 Catalysts

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1431
Author(s):  
Andrey Yasinskiy ◽  
Sai Krishna Padamata ◽  
Srecko Stopic ◽  
Dominic Feldhaus ◽  
Dmitriy Varyukhin ◽  
...  
Keyword(s):  
Precious Metals ◽  
Cyclic Voltammograms ◽  
Spent Catalyst ◽  
Tungsten Electrode ◽  
Primary Metal ◽  
Aluminum Reduction ◽  
Electron Process ◽  
Alumina Solubility ◽  
Spent Catalysts ◽  
The One

Electrochemical decomposition of spent catalyst dissolved in molten salts is a promising approach for the extraction of precious metals from them. This article reports the results of the study of aluminum electrowinning from the xLiF–(1-x)AlF3 melt (x = 0.64; 0.85) containing 0–5 wt.% of spent petroleum Pt/γ-Al2O3 catalyst on a tungsten electrode at 740–800 °C through cyclic voltammetry and chronoamperometry. The results evidence that the aluminum reduction in the LiF–AlF3 melts is a diffusion-controlled two-step process. Both one-electron and two-electron steps occur simultaneously at close (or same) potentials, which affect the cyclic voltammograms. The diffusion coefficients of electroactive species for the one-electron process were (2.20–6.50)∙10−6 cm2·s–1, and for the two-electron process, they were (0.15–2.20)−6 cm2·s−1. The numbers of electrons found from the chronoamperometry data were in the range from 1.06 to 1.90, indicating the variations of the partial current densities of the one- and two-electron processes. The 64LiF–36AlF3 melt with about 2.5 wt.% of the spent catalysts seems a better electrolyte for the catalyst treatment in terms of cathodic process and alumina solubility, and the range of temperatures from 780 to 800 °C is applicable. The mechanism of aluminum reduction from the studied melts seems complicated and deserves further study to find the optimal process parameters for aluminum reduction during the spent catalyst treatment and the primary metal production as well.

scholarly journals Quantification of Classified Nickel Species in Spent FFC Catalysts

2021 ◽  
Author(s):  
Monica Dapiaggi ◽  
Marco Alloni ◽  
Riccardo Carli ◽  
Nicola Rotiroti ◽  
Giorgia Confalonieri
Keyword(s):  
Zeolite Y ◽  
Complex Matrix ◽  
Spent Catalyst ◽  
Quick Method ◽  
Spent Catalysts ◽  
The Law ◽  
The One ◽  
Nickel Species

Abstract The paper presents a quick method for the quantification of nickel species in spent FFC catalysts; the quantification of known quantities NiO and $$\hbox{NiAl}_2\hbox{O}_{4}$$ NiAl 2 O 4 is first done in a matrix of fresh zeolite Y, and then in a complex matrix, similar to the one of a real spent catalyst. The method is carefully checked and the errors in the quantification are critically evaluated. After the validation of the method with known quantities of NiO, well below the law limit for direct re-use, a set of real spent catalysts (representative of a period of 12 months) is analysed. Graphic Abstract

scholarly journals A “Wastes-Treat-Wastes” Technology: Role and Potential of Spent Fluid Catalytic Cracking Catalysts Assisted Pyrolysis of Discarded Car Tires

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2732
Author(s):  
Baishun Zhao ◽  
Chuansheng Wang ◽  
Huiguang Bian
Keyword(s):  
Catalytic Cracking ◽  
Precious Metals ◽  
Cost Effective ◽  
Fluid Catalytic Cracking ◽  
Spent Catalyst ◽  
Waste Tires ◽  
Waste Tire ◽  
Spent Catalysts ◽  
Fcc Catalysts ◽  
Cracking Catalysts

Spent fluid catalytic cracking catalysts (FCC catalysts) produced by the petrochemical industry are considered to be environmentally hazardous waste, and precious metals and heavy metals deposited on the surface make them difficult to treat. Even so, these catalysts retain some of their activity. The pyrolysis of waste tires is considered to be one of the most effective ways to solve the fossil fuel resource crisis, and this study attempts to catalyze the pyrolysis of waste tires using spent catalysts to increase the value of both types of waste. FCC catalysts reduced the activation energy (E) of waste tire pyrolysis. When the catalyst dosage was 30 wt.%, the E of tread rubber decreased from 238.87 kJ/mol to 181.24 kJ/mol, which was a 19.94% reduction. The E of the inner liner decreased from 288.03 kJ/mol to 209.12 kJ/mol, a 27.4% reduction. The spent catalyst was more effective in reducing the E and solid yield of the inner liner made of synthetic rubber. It should be emphasized that an appropriate increase in the heating rate can fully exert the selectivity of the catalyst. The catalyst could also be effectively used twice, and the optimum ratio of catalyst/waste tires was about 1/4.5. Compared with specially prepared catalysts, it is more cost-effective to use such wastes as a catalyst for waste tire pyrolysis.

scholarly journals Research on Hazardous Waste Removal Management: Identification of the Hazardous Characteristics of Fluid Catalytic Cracking Spent Catalysts

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2289
Author(s):  
Haihui Fu ◽  
Yan Chen ◽  
Tingting Liu ◽  
Xuemei Zhu ◽  
Yufei Yang ◽  
...  
Keyword(s):  
Surface Water ◽  
Hazardous Waste ◽  
Environmental Quality ◽  
Catalytic Cracking ◽  
Petroleum Refining ◽  
Fluid Catalytic Cracking ◽  
Refining Industry ◽  
Spent Catalyst ◽  
Spent Catalysts ◽  
Petroleum Refining Industry

Fluid catalytic cracking (FCC) spent catalysts are the most common catalysts produced by the petroleum refining industry in China. The National Hazardous Waste List (2016 edition) lists FCC spent catalysts as hazardous waste, but this listing is very controversial in the petroleum refining industry. This study collects samples of waste catalysts from seven domestic catalytic cracking units without antimony-based passivation agents and identifies their hazardous characteristics. FCC spent catalysts do not have the characteristics of flammability, corrosiveness, reactivity, or infectivity. Based on our analysis of the components and production process of the FCC spent catalysts, we focused on the hazardous characteristic of toxicity. Our results show that the leaching toxicity of the heavy metal pollutants nickel, copper, lead, and zinc in the FCC spent catalyst samples did not exceed the hazardous waste identification standards. Assuming that the standards for antimony and vanadium leachate are 100 times higher than that of the surface water and groundwater environmental quality standards, the leaching concentration of antimony and vanadium in the FCC spent catalyst of the G set of installations exceeds the standard, which may affect the environmental quality of surface water or groundwater. The quantities of toxic substances in all spent FCC catalysts, except those from G2, does not exceed the standard. The acute toxicity of FCC spent catalysts in all installations does not exceed the standard. Therefore, we exclude “waste catalysts from catalytic cracking units without antimony-based passivating agent passivation nickel agent” from the “National Hazardous Waste List.”

scholarly journals STABILISASI TANAH EKSPANSIF MENGGUNAKAN KAPUR DAN SPENT CATALYST UNTUK TANAH DASAR PERKERASAN

2019 ◽  
Vol 19 (1) ◽  
pp. 21-30
Author(s):  
Arifudin Nur ◽  
Suryo Hapsoro Tri Utomo ◽  
M. Zudhy Irawan
Keyword(s):  
Soil Stabilization ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Petroleum Processing ◽  
Spent Catalyst ◽  
Maximum Increase ◽  
Lime Content ◽  
Road Pavement ◽  
Pozzolanic Material ◽  
Spent Catalysts

Abstract Expansive soils have high swelling and shrinkage potentials, which may cause damage to road structures. Therefore, stabilization is required. One method of stabilization is to use lime and spent catalysts with the aim of increasing carrying capacity and reducing swelling. Spent catalyst is a petroleum processing waste and classified as pozzolanic material. The addition of lime and spent catalysts can increase the CBR value and reduce swelling of soils. The results of this study indicate that the maximum increase in soaked CBR and unsoaked CBR values occurred in soil mixtures with optimum lime content and 12% spent catalyst with 7 days of curing. While the soil mixture with optimum lime content and 12% spent catalyst, with 7 days of curing, is the best mixture that produces soaked CBR value of 49.67%, swelling of 0.15%, and plasticity index value of 11.97%, so the soil meets the requirements to be used as pavement subgrade. Keywords: expansive soil, stabilization, road structure, subgrade, road pavement  Abstrak Tanah ekspansif memiliki potensi pengembangan dan penyusutan yang tinggi, sehingga dapat menyebabkan kerusakan struktur jalan. Oleh sebab itu, perlu dilakukan stabilisasi. Salah satu metode stabilisasi adalah menggunakan kapur dan spent catalyst dengan tujuan meningkatkan kapasitas dukung dan menurunkan swelling. Spent catalyst merupakan limbah pengolahan minyak bumi dan termasuk bahan pozzolan. Penam-bahan kapur dan spent catalyst mampu meningkatkan nilai CBR dan mereduksi swelling. Hasil studi ini menunjukkan bahwa peningkatan maksimum nilai CBR soaked maupun CBR unsoaked terjadi pada campuran tanah dengan kadar kapur optimum dan 12% spent catalyst dengan peraman 7 hari. Sedangkan campuran tanah dengan kadar kapur optimum dan 12% spent catalyst, dengan peraman 7 hari, merupakan campuran terbaik yang menghasilkan nilai CBR soaked sebesar 49,67%, swelling sebesar 0,15%, dan nilai indeks plastisitas sebesar 11,97%, sehingga tanah memenuhi syarat untuk digunakan sebagai tanah dasar perkerasan jalan. Kata-kata kunci: tanah ekspansif, stabilisasi, struktur jalan, tanah dasar, perkerasan jalan

Frontier, Backlands, and Indigenous Presence in Colonial São Paulo

2021 ◽  
Author(s):  
José Carlos Vilardaga
Keyword(s):  
Indigenous People ◽  
Indigenous Peoples ◽  
18Th Century ◽  
Geographical Area ◽  
Precious Metals ◽  
Sao Paulo ◽  
Colonial Period ◽  
Acting Out ◽  
São Paulo ◽  
The One

The residents of the Captaincy of São Vicente, which would become São Paulo in the 18th century, were known in the late 17th century as “Paulistas.” Their reputation in the colonial period was ambiguous: on the one hand, they were viewed as crude and unruly enslavers of Indigenous people; on the other, they were known as skilled backwoodsmen and soldiers. This image derived mainly from a character that would later come to be known as the bandeirante, a member of the expeditions that forged into remote backlands mainly to capture Indigenous people for their own use, without waiting for orders from the Crown or church. This source of labor enabled the internal reproduction of enslaved labor in a region whose economy was based on subsistence and supplying other regions in the high plateau where São Paulo de Piratininga was established in 1554, first as a school, later as a town. As the occupation of the region advanced over the following decades, a network of chapels, parishes, and towns linked by river and overland routes grew up, forming the geographical area of the colonial captaincy. This occupation, which extended to the remote edges of the regions that would eventually make up Brazil and even into frontier lands contested by both Iberian empires, was motivated by a search for Indigenous peoples, a quest for precious metals, a demand for land, and the dictates of political disputes. In this sense, the backwoodsmen were not acting out of a strategic geopolitical motivation, as a certain school of self-congratulatory historiography would have it. In any event, the Paulistas played a role in shaping the internal and external frontiers of colonial Brazil through the 18th century in the context of the boundary treaties. The society formed under these circumstances was intrinsically tied to the Indigenous world, to the backlands, and to frontier living, and resulted in varied forms of crossbreeding and cultural interactions embodied in the mestizo type that became known as mameluco; the violent practices inherent in colonization, however, cannot be overlooked.

scholarly journals A review of the valorization and management of industrial spent catalyst waste in the context of sustainable practice: The case of the State of Kuwait in parallel to European industry

2019 ◽  
Vol 37 (11) ◽  
pp. 1127-1141 ◽  
Author(s):  
Sultan Majed Al-Salem ◽  
Achilleas Constantinou ◽  
Gary Anthony Leeke ◽  
Sanaa Hafeez ◽  
Tayeba Safdar ◽  
...  
Keyword(s):  
Waste Management ◽  
Industrial Waste ◽  
The State ◽  
Chemical Recovery ◽  
Spent Catalyst ◽  
World Region ◽  
Spent Catalysts ◽  
The State Of Kuwait ◽  
Sustainable Practice ◽  
Recovery Methods

Industrial solid waste management encompasses a vital part of developed and developing countries strategies alike. It manages waste generated from vital industries and governs the hazardous waste generated as a major component of integrated waste management strategies. This article reviews the practices that govern the management approaches utilized in the developed world for industrial spent catalysts. It critically assesses the current situation of waste management within the developing world region focusing on the industrial waste component, in a novel attempt to crucially develop a strategy for a way forward based on best practices and future directions with major European industries. The review also draws parallels with European countries to compare their practices with those of the State of Kuwait, which rely solely on landfilling for the management of its industrial waste. Spent catalysts recovery methods are discussed at length covering conventional methods of valuable metals and chemicals recovery (e.g., hydrometallurgical, solid–liquid and liquid–liquid extraction) as well as biological recovery methods. A major gap exists within regulations that govern the practice of managing industrial waste in Kuwait, where it is essential to start regulating industries that generate spent catalysts in-view of encouraging the establishment of valorization industries for metal and chemical recovery. This will also create a sustainable practice within state borders, and can reduce the environmental impact of landfilling such waste in Kuwait.

Recovery of Heavy Metals from the Spent Catalyst of the Hydrotreating Unit (HDT) for the Use of the Impregnation of Supported Catalysts

2018 ◽  
Vol 792 ◽  
pp. 133-139 ◽  
Author(s):  
Toapanta Germania ◽  
Caterine Donoso ◽  
María José Cárdenas ◽  
Amón Bolívar ◽  
Vladimir Ortiz
Keyword(s):  
Heavy Metals ◽  
Nitric Acid ◽  
Acid Concentration ◽  
Supported Catalysts ◽  
Nitric Acid Concentration ◽  
Added Value ◽  
High Tech ◽  
Spent Catalyst ◽  
X Ray ◽  
Spent Catalysts

Spent catalysts contain metals that have a high added value. From all metals, lanthanum has attracted a lot of attention due to the growing demand in the high-tech. The spent catalyst of the hydrotreatment unit is a material composed of lanthanum-enriched matrix of amorphous aluminosilicates. The experiment was carried out with a spent catalyst with a constant particle size of 90 μm. The treatments were obtained applying of two level factorial design to investigate the effect of following factors: temperature (20 - 60 °C), nitric acid concentration (3 - 6 M), leaching time (1 - 4 h) and percent solids (10 - 20 %). The research is carried out in two steps process: pretreatment of the catalyst and leaching with nitric acid. The leaching results show a yield of lanthanum of 99.44% using the following conditions: temperature (20 °C), nitric acid concentration (3M), leaching time (1 h), percent solids (20%) and 300 rpm. The principal analysis of the spent catalyst was carried out using the X-Ray Fluorescence (XRF) technique, 3.08%, while the percentage of lanthanum recovery in the extract, washing and refining was carried out using the Inductive Coupling Plasma (ICP) technique.

scholarly journals Model of Infiltration of Spent Automotive Catalysts by Molten Metal in Process of Platinum Metals Recovery

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Agnieszka Fornalczyk ◽  
Slawomir Golak ◽  
Mariola Saternus
Keyword(s):  
Electromagnetic Field ◽  
Molten Metal ◽  
Metal Flow ◽  
Precious Metals ◽  
Automotive Catalysts ◽  
Catalyst Carrier ◽  
Metals Recovery ◽  
Spent Catalysts ◽  
Hydrodynamic Field ◽  
The Impact

This paper presents the model for the washing-out process of precious metals from spent catalysts by the use of molten lead in which the metal flow is caused by the rotating electromagnetic field and the Lorentz force. The model includes the coupling of the electromagnetic field with the hydrodynamic field, the flow of metal through anisotropic and porous structure of the catalyst, and the movement of the phase boundary (air-metal) during infiltration of the catalyst carrier by the molten metal. The developed model enabled analysis of the impact of spacing between the catalysts and the supply current on the degree of catalyst infiltration by the molten metal. The results of calculations carried out on the basis of the model were verified experimentally.

Modelling Methods of Magnetohydrodynamic Phenomena Occurring in a Channel of the Device Used to Wash out Spent Automotive Catalyst on Metallic Substrate by a Liquid Metal

2016 ◽  
Vol 879 ◽  
pp. 566-571
Author(s):  
Agnieszka Fornalczyk ◽  
Roman Przylucki ◽  
Sławomir Golak ◽  
Mariola Saternus
Keyword(s):  
World Literature ◽  
Precious Metals ◽  
Coupled Analysis ◽  
Computational Techniques ◽  
Catalytic Converters ◽  
Advantages And Disadvantages ◽  
Spent Catalysts ◽  
Physical Fields ◽  
Modelling Methods ◽  
Temperature And Flow Fields

The recovery of precious metals is necessary for environmental and economic reasons. Spent catalysts from automotive industry containing precious metals are very attractive recyclable material because as the devices. they have to be periodically renovated and eventually replaced. Among automotive catalysts withdrawn from use, these with metallic carrier constitute quite a big group. Metallic carriers are usually obtained from steel FeCrAl , which is covered by a layer of PGM acting as a catalyst. World literature describes a number of pyro-or hydrometallurgical methods used for recovery of platinum from used automobile catalytic converters. However, all methods, available in the literature, are used to recover platinum from ceramic carrier. This paper presents the new method of removing platinum from the spent catalytic converters applying lead as a collector metal in a device used to wash out platinum by using mangetohydrodynamic pump. The article includes the description of the methods used in modelling magnetohydrodynamic phenomena (coupled analysis of the electromagnetic, temperature and flow fields) occurring in this particular device for this kind of waste. The general phenomena and ways of coupling the various physical fields for this type of calculation have also been described. The basic computational techniques with a discussion of their advantages and disadvantages have been presented.

The Homeric Talent, its Origin, Value, and Affinities

1887 ◽  
Vol 8 ◽  
pp. 133-158 ◽  
Author(s):  
William Ridgeway
Keyword(s):  
Precious Metals ◽  
The Other ◽  
Primitive Form ◽  
Other Hand ◽  
Two Systems ◽  
Actual Use ◽  
The One

This paper is an endeavour to discover (1) the origin, (2) the value, and (3) the affinity of the Talent of the Homeric Poems to other systems. In those Poems we find two systems of denominating value, the one by the ox (or cow), or the value of an ox, the other by the talent (τάλαντον). The former is the one which has prevailed and does still prevail in barbaric communities, such as the Zulus, where the sole or principal wealth consists in herds and flocks. For several reasons we may assign to it priority in age as compared with the talent. For as it represents the most primitive form of exchange, the barter of one article of value for another, before the employment of the precious metals as a medium of exchange, consequently the estimation of values by the ox is older than that by a talent or ‘weight’ of gold, or silver, or copper. Again in Homer all values are expressed in so many beeves, e.g. (Il. vi. 236.)The talent on the other hand is only mentioned in relation to gold; for we never find any mention of a talent of silver. But the names of monetary units hold their ground long after they themselves have ceased to be in actual use, as we observe in such common expressions as ‘bet a guinea,’ or ‘worth a crown,’ although these coins themselves are no longer in circulation.

Sign in / Sign up

Export Citation Format

Share Document