Sulphur Separation by Heat Treatment of Petroleum Coke

U radu je ispitan utjecaj uvjeta toplinske obrade (temperatura, vrijeme i brzina zagrijavanja) na svojstva naftnog koksa. Ispitani uzorci su koksevi proizvedeni iz različitih sirovina za koksiranje. Praćeni su sadržaj sumpora, isparljivih tvari, pepela i gustoća, prije i nakon toplinske obrade do 2 400 °C. Rezultati ukazuju na djelomično odsumporavanje koksa u uvjetima provedenih ispitivanja. Fazna analiza je pokazala da tijekom toplinske obrade dolazi do izdvajanja i transformacije spojeva anorganskog sumpora. Najstabilniji spojevi sumpora su sulfidi identificirani u koksevima i nakon toplinske obrade pri 2 400 °C.The impact of heat treatment (temperature, heat-soak time and heating rate) on petroleum coke properties were examined. Investigated coke produced from feedstock with different compositions. The sulphur content, volatile matter, density value and ash content before and after heat treatment to 2 400 °C were analysed. Results implies partially desulphurization of the coke by performed examinations. Phase analysis of the cokes showed that during the heating, separation and transformation of some inorganic sulphur compounds took place. The sulphides are most stable sulphur compounds identified even after heating coke at 2 400 °C

Properties of carbon anode components for aluminium production

Kvaliteta ugljičnih elektroda-anoda ovisi o karakteristikama koksnog punila, katranske vezivne smole i anodnog ostatka koji su komponente zelene anodne mješavine. Naftni koks je prevladavajuća komponenta anode koja se primjenjuje u proizvodnji aluminija. Prisutnost netopljivih tvari u katranskoj smoli ima znatan utjecaj na mikrostrukturu i ostala svojstva ugljične anode. Prikazani su međusobna zavisnost fizikalno-kemijskih svojstava naftnog koksa, vezivne katranske smole i anodnog ostatka te njihov utjecaj na stabilnost anode. Diskutirana je povezanost svojstava i mikrostrukture komponenti anode i njezine kvalitete.The quality of carbon electrode-anode depends on characteristics of coke filler, coal tar pitch binder and anode scrap, which are the components of green anode mixture. Petroleum coke is a dominant component of anode, which finds application in the aluminium production. The interdependence of physical-chemical properties of the petroleum coke, coal tar pitch binder and anode scrap and their influence on the stability of anode are shown. The presence of insoluble substances in coal tar pitch exerts a strong influence upon the microstructure and other properties of carbon anode. The connection of the properties and microstructure of anode components and anode quality is discussed

PROPERTIES OF THE CHEMICALLY ACTIVATED CARBON ANODE DUST

Ugljična anodna prašina (UAP) otpadni je materijal pri proizvodnji aluminija. Kemijski sastav UAP određen je metodom apsorpcijske spektrometrije (AAS), a mineraloški sastav metodom difrakcije rendgenskog zračenja (XRD). Površinska svojstva (specifična površina, prosječni promjer pora i ukupni volumen pora) određeni su Brunauer Emmett Telleorovom (BET) metodom i Barrett-Joyner-Halendainom (BJH) metodom. Mikroskopska ispitivanja provedena su pretražnom elektronskom mikroskopijom (SEM). Sva su ispitivanja provedena prije i nakon kemijske aktivacije UAP s KOH, ZnCl2 i organskim kiselinama (octenom i limunskom). Dobiveni rezultati pokazali su pozitivan utjecaj kemijske aktivacije na kemijska i strukturna svojstva ugljične anodne prašine kao potencijalnoga jeftinog adsorbensa.The carbon anode dust (CAD) is waste material of the aluminium production industry. The chemical and mineralogical composition of CAD was examined by atomic absorption spectroscopy (AAS) and the X-ray diffraction method (XRD), respectively. Surface area properties (specific surface area, average pore diameter, total pore volume) are determined by the Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods. Microscopic observation was conducted using scanning electron microscopy (SEM method). All of investigations were performed before and after chemical activation of CAD by KOH, ZnCl2 and by organic acids (acetic and citric). The results obtained suggest the positive effect of chemical activation on the chemical and structural properties of carbon anode dust as a potentially low-cost adsorbent

The change in surface area properties of blast furnace sludge treated by citric acid

The blast furnace sludge (BFS) is a waste material of pig iron production. The chemical and mineralogical composition of BFS was examined by Proton Induced X-ray Emission (PIXE) and X-ray Diffraction (XRD) methods. Surface area properties (specific surface area, average pore diameter, total pore volume) are determined by the Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) method. The microscopic observation was conducted using a scanning electron microscopy (SEM method). Chemical treatment of BFS was performed by adsorbed citric acid. Thermal treatment was done by heating at 700°C. The surface properties of the blast furnace sludge are compared to those obtained after treatment. The results have shown that this successfully performed experiment modified the surface of BFS as a potentially low-cost adsorbent

REMOVAL OF Ni(II) FROM AQUEOUS SOLUTION BY LOW-COST ADSORBENTS

The use of low-cost adsorbents has been investigated as a replacement for costly adsorbents and methods of removing nickel ions from aqueous solution. The purpose of this review article is to provide the scattered available information on various aspects of utilization of low-cost adsorbents derived from agricultural waste, industrial by-products and waste material or natural material. To highlight their technical applicability, selected information on initial nickel concentration, pH level, dose required, adsorption capacity, temperature, thermodynamic data, adsorption isotherm, adsorption kinetics is presented. In generall, technical applicability and cost-effectiveness are the key factors in the selection of the most suitable adsorbent to treat aqueous solution contain nickel ions

Removal of Cr(VI) from aqueous solution by a commercial carbon black

Hexavalent chromium is classified as a human carcinogen of high carcinogenic hazard according to the US EPA. Therefore, batch adsorption experiments aiming at Cr(VI) removal from an aqueous solution were carried out using a commercial carbon black (CB) as an adsorbent. The CB wascharacterized by the Brunauer–Emmett– Teller and Barrett–Joyner–Halenda, scanning electron microscopy with energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy methods. Various parameters were tested, including adsorbent dose, solution pH, contact time, initial metal concentration, and temperature, so as to determine their relation to the adsorption yield. The results showed that an initial solution of pH 2.4 was most favorable for the Cr(VI) removal. The equilibrium data were analyzed by the Freundlich, Langmuir, and Temkin isotherm models. The equilibrium data best fitted according to the Freundlich isotherm model. The CB maximum adsorption capacity was found at 33.22 mg/g, thus proved to be promisingly efficient in comparison to other low-cost adsorbents. The thermodynamic parameters yielded by this study showed that theCr(VI) adsorption on the CB was the spontaneous exothermic process

Dynamics and thermodynamics of a nickel uptake from a water system onto the blast furnace sludg

This study describes the use of blast furnace sludge (BFS) for the removal of toxic Ni(II) ions from a water system.Blast furnace sludge is a by-product and a waste material of the steelmaking industry. Chemical and mineralogical characteristics of BFS are determined by Proton Induced X-ray Emission and X-ray Diffraction methods.The surface area properties are determined by the Brunauer-Emmett-Teller method. The adsorption is investigated in a batch adsorption system in view of its kinetics and thermodynamics. The kinetic experiments show that the adsorption process follows a pseudo-second order model. The adsorption mechanism is investigated by intra-particle diffusion and Boyd-Reichenberg kinetic models. Thermodynamic parameters (activation free energy change, activation enthalpy change, and activation entropy change) reveal that the adsorption of Ni(II) on BFS is spontaneous, exothermic, and chemical in nature. The results suggest that BFS is an inexpensive and efficient adsorbent for the removal of Ni(II) ions from aqueous solutions

The Use of Metallurgical Coke as Carburizing Material in the Foundry

The properties of metallurgical cokes obtained in a laboratory from pure coal and with additives (light atmospheric residue of oil distillation and coal tar pitch) after heat treatment to 1600 °C were investigated. Changes in the basic characteristics (density, moisture, ash, metal and sulphur contents) were examined. Crystallographic parameters (crystallite size, Lc and interlayer spacing, d002) and surface morphology were also determined. The results were compared to data on a commercial carburizing material used in foundries, known as “Karbina”. The metallurgical coke produced by mixing coal and coal tar pitch is good for thermal conversion to a semigraphitic structure at higher temperatures (1600 °C). Because of this and its physical-chemical characteristics the material is recommended as a suitable carburizing material

Characterization of Ladle Furnace Slag from Carbon Steel Production as a Potential Adsorbent

A promising type of steel slag for applications is the ladle furnace (LF) slag, which is also known as the basic slag, the reducing slag, the white slag, and the secondary refining slag. The LF slag is a byproduct from further refining molten steel after coming out of a basic oxygen furnace (BOF) or an electric arc furnace (EAF). The use of the LF slag in further applications requires knowledge of its characteristics. The LF slag characterization in this paper has been performed using the following analytical methods: chemical analysis by energy dispersive spectrometry (EDS), mineralogical composition by X-ray diffraction (XRD), surface area properties by the Brunauer-Emmett-Teller (BET) and the Barrett-Joyner-Halenda (BJH) methods, surface chemistry by infrared absorption (FTIR) spectroscopy, and morphological analysis by scanning electron microscopy (SEM). The results showed that the main compounds are calcium, silicon, magnesium, and aluminium oxides, and calcium silicates under their various allotropic forms are the major compounds in the LF slag. Surface area properties have shown that the LF slag is a mesoporous material with relatively great BET surface area. The ladle furnace slag is a nonhazardous industrial waste because the ecotoxicity evaluation by its eluate has shown that the LF slag does not contain constituents which might in any way affect the environment harmfully