Electric Furnace Research Articles

Physical and mechanical characteristics of refractories for the vitrification furnace of highly active waste

The results of experimental measurements of mechanical and physical characteristics of refractory materials are presented: TCLE, thermal conductivity, heat capacity, dynamic and static modulus of elasticity. The study was carried out to select the material for the manufacture of the vault of a glass furnace for curing radioactive waste. It is shown that the materials of the MKRV-53 and AZS- 60SB brands are superior in their characteristics to the material of the BMKrF brand. The obtained results are used for mathematical modeling of the operating modes of the electric furnace arch. Ill. 3. Ref. 7. Tab. 7.

Corrosion testing of domestically produced baddeleyitecorundum and chromium-containing materials in borosilicate glass melts

Practical importance of corrosion and erosion resistance of refractories was justified for the design of furnaces with direct electric heating that are used for vitrification of high-level waste (HLW). The main promising materials are listed, and the algorithm of assessment of their resistance to the effects of borosilicate melts is given for the operating conditions of electric furnaces. Corrosion testing of refractories was carried out under static and dynamic conditions in a low-melting borosilicate glass melt and in a borosilicate glass melt containing simulated liquid HLW. Refractory materials were selected that have the highest resistance in a glass melt under conditions of HLW immobilization. The testing results will be used for choosing lining material in the design of removable and small-scale melters. Ill. 5. Ref. 11. Tab. 3.

The Influence of Fiber Treatment and Matrix Type on the Impregnation Quality of Carbon Fiber Reinforced Thermoplastics

One of the main issues with Carbon Fiber Reinforced Thermoplastics (CFRTP) is the poor impregnation quality of the matrix on carbon fiber due to the high viscosity of the thermoplastic. Impregnation quality can significantly affect the mechanical properties of the composite. This study aims to compare the impregnation abilities of various types of thermoplastic matrices on carbon fiber. The matrices used in this study are HDPE, PC, and PET. Three variations of carbon fiber treatment were employed: the first variation involved immersion in liquid nitrogen at -196°C, the second variation included heating in an electric furnace at 600°C followed by rapid cooling in liquid nitrogen, and the third variation utilized treatment with a silane coupling agent. The research findings demonstrate that composites comprising a Polycarbonate matrix and carbon fiber reinforcement, treated with a silane coupling agent, exhibit superior impregnation quality, as evidenced by an Interfacial Shear Strength (IFSS) value of 9.34 MPa.. The lowest impregnation quality was observed in HDPE reinforced with carbon fiber that had been heated and rapidly cooled, with an IFSS of 5.52 MPa.

Deportment of Metals from E-Waste PCBs towards Alloy and Slag Phases during Smelting Using CaO-Al2O3-SiO2-B2O3 Slags

Printed circuit boards (PCBs) from antiquated electronic goods were processed by a pyrometallurgical route to produce and separate alloy and slag phases. The process involved initial size reduction of PCBs, followed by pyrolysis at 500 °C for 6 h and finally smelting of the solid materials in an electric furnace. A preliminary smelting test was performed at 1600 °C to estimate the composition of the slag generated. In later kilogram-scale smelting experiments, B2O3 flux was added along with CaO and SiO2 to decrease the liquidus temperature required to smelt the PCBs. The level of fluxing was adapted from earlier phase equilibria studies of the CaO-Al2O3-SiO2-B2O3 slag system. Results showed that the flux decreased the melting temperature and assisted the recovery of most valuable metals within the alloy phase at 1350 °C smelting temperature. The alloy phase recovered 99.8% of Cu, 99% of Sn, and 100% of precious metals (Au, Ag, Pt). A fluxing strategy for smelting high Al2O3 containing e-waste PCBs was proposed based on the experimental findings of this research.

EFFECT OFTHE SUBSTITUTION OF Bi→Sb ON THE STRUCTURE CHANGES WITHIN THE AgBi1-xSbxS2 (x = 0 - 1) SOLID SOLUTION

The work is devoted to study effect of the isovalent substitution on the parameter of structure elements of the crystal structure of the AgBi1-xSbxS2 (x = 0 – 1) solid solution. The limited isostructural phases of the solid solution have a cubic system with space group Fm-3m. The samples of individual composition of the AgBi1-xSbxS2 (x = 0 – 1) solid solution were obtained in quartz vacuumed ampoules in an electric muffle furnace with MP-30 software control of technological processes. The X-ray powder diffractograms that were recorded with using the DRON 4-13 diffractometer have been analyzed using WinCSD software package. The visualization of the crystal structure has been made with VESTA program. It is worth noting that the method of solid phase reactions allows synthesizing sufficiently pure materials, which are suitable for the measure of physical properties. The change of cell parameters within a solid solution is described by a positive deviation from the Vegard’s law. Only all octahedral voids are filled in the structure. It is important to see the prospect of possible alloying by atoms with small atomic radii, which may be localized in tetrahedral voids. The change of volume of the octahedral voids is linear.
 Keywords: crystal structure; solid solution; unit cell.

Compressive Strength Behavior of Briquettes Produced from Manganese Ore Fines and Metal Dust: Optimization Using Response Surface Methodology

ABSTRACT Electric reduction furnaces cannot be fed fines in the production of manganese ferroalloy as they hinder gas permeability. Thus, agglomeration techniques can be used to minimize the environmental and economic impacts of storing fines. Among these techniques, briquetting is advantageous because it allows for cold agglomeration of the particles and is flexible in terms of particle sizes. Therefore, this work aimed to develop self-reductor briquettes composed of ore manganese fines, dust ferromanganese, charcoal fines, and three different binders. The compaction pressure, curing time, and % binder were optimized to enhance briquette strength through a multivariate experimental design consisting of a screening study using a 23 full factorial design followed by response surface methodology with a spherical central composite design. The results were assessed by analysis of variance, and a regression model was established. The study found that briquettes elaborated with bentonite exhibited an optimized compressive strength of 4.02 MPa, achieved with a compaction pressure of 67.55 MPa and 12.71% bentonite. For briquettes elaborated with pregelatinized starch, a compressive strength of 7.04 MPa was obtained with a compaction pressure of 67.52 MPa, a curing time of 19.51 days, and 8.07% pregelatinized starch. For briquettes agglomerated using slaked lime and molasses, an optimized compaction pressure of 27.09 MPa and a curing time of 23.27 days resulted in a compressive strength of 1.63 MPa. These results suggest that briquettes containing bentonite and pregelatinized starch are feasible substitutes for lump ore in electric furnaces.

H2O2 assisted steel slag nanocomposite for degradation of organic pollutant in an advanced oxidation process for suspension and Spin-Coated mode

Electrical Furnace Steel slag (EAF) was converted into steel slag nanocomposite (SSNC) by solvothermal preparation technique and assisted by H2O2 for Fenton and photo-Fenton-like degradation of six different dyes in both suspension and spin-coated modes. The physico-chemical properties were evaluated using various characterization tools. The result reveals that the EAF-SSNC exhibited nanocomposite behaviour. As a substrate for studying the advance oxidataion processes, methylene blue (MB) was first used. The kinetic study followed the pseudo-first-order reaction kinetics. The effect of operating factors was studied using the response surface methodology. Based on the optimum parameters, five reusability test was performed for both suspension and spin-coated mode, where 92.89% of MB was degraded in the fifth cycle for suspension mode and 88.21% for spin-coated mode. The photodegradation efficiency of methylene blue, methyl red, rhodamine-B, Congo red, acid blue-25, and methyl orange were 85.84%, 74.62%, 70.53%, 58.66%, 45.21%, and 40.38%, respectively, at a neutral pH. The effect of scavenger and total organic carbon (TOC) were analyzed. Moreover, the degradation pathway was identified using an LC-mass spectrometer. This work showed that slag nanocomposite is effective for dye degradation and lowering the overall cost of the Fenton process at a neutral pH.

MAGNETIC-CONTROLLED SORBENT FOR WATER SURFACE CLEANING FROM OIL POLLUTION

The modern structure of industry, outdated technologies form a wide range of environmental problems and sharply worsen the ecological situation. Various methods are used to clean water sources from oil spills: mechanical, thermal, physicochemical, biological. Among the available alternatives, oil sorbents are considered as one the most economical, efficient and environmentally friendly materials because oils can be properly absorbed by oil sorbents without causing secondary water pollution.
 The purpose of the research is to study the possibility of obtaining an effective magnetically controlled sorption material for cleaning the water surface from oil spills.
 Research objectives are to analyze the composition of electric arc steel-smelting furnaces (EASSF) dust; conduct research on the hydrophobization EASSF dust with paraffin; determine the optimal proportions of dust and hydrophobizator, which allow the material to maintain buoyancy and magnetic susceptibility; evaluate the interaction of the obtained material with an oil spills on water surface.
 The dust sample elemental composition was obtained using the ARL9900 Intellipower Workstation.
 The sorption material was prepared as follows: the EASSF dust was mixed with a sample of paraffin, then it was heated to 105 °C in an oven, mixed, and cooled to a temperature of 20 °C.
 The true density was determined by the pycnometric method. The method ASTM D2854-70 «Standard Test Method for Apparent Density of Activated Carbons» was used to determine the bulk density.
 Electric steelmaking waste was used as a magnetically susceptible component. Studies have been carried out on its hydrophobization with paraffin for possible use in water treatment. With the waste : paraffin ratio of 1 : 0.07, a material with high hydrophobicity and buoyancy was obtained. Tests for thickening and extracting a crude oil spill from water surface proved the promise of using the obtained material for cleaning water from oil pollution.

The Thermochemical Conversion of Municipal Solid Waste by Torrefaction Process

In this work, the thermochemical properties of municipal solid waste (MSW) are studied using the torrefaction process as the main method for investigation. Torrefaction experiments were carried out using an electric laboratory furnace, at temperatures of 200, 250, and 300 °C. The residence time was set to 90 min. Proximate and ultimate analysis were performed on the torrefied MSW samples and compared with the properties of the raw MSW samples. In addition, the thermal properties of the obtained torrefied MSW samples were evaluated by thermogravimetric analysis (TGA) and derivative thermogravimetric analysis (DTG). The following could be stated: the obtained results showed that mass and energy yields (MY and EY, respectively) decrease with increasing when torrefaction temperature, while the heating values (HHV) increased under the same conditions (from 24.3 to 25.1 MJ/kg). Elemental analysis showed an increase in carbon content (C), from 45.7 ± 0.9 to 52.8 ± 1.05 wt.%, and decrease in oxygen content (O), from 45.6 ± 0.9 to 39.5 ± 0.8 wt.%, when torrefaction temperature is increased, which is consistent with the general definition of the torrefaction process. In addition, enhancement factors (EFs) and fuel ratios (FRs) were calculated, which ranged from 1.00 to 1.02 and 0.16 to 0.23, respectively. Some anomalies were observed during the thermal analysis, which are assumed to be related to the composition of the selected MSW. This study therefore shows that torrefaction pretreatment can improve the physicochemical properties of raw MSW to a level comparable to coal, and could contribute to a better understanding of the conversion of MSW into a valuable, solid biofuel.

Influence of the calcination method and anode composition on the generation of disinfectants

Developing highly selectivity anode materials for hypochlorite generation in low-concentrated sodium chloride (NaCl) solutions is challenging. Here, we describe the synthesis and physical and electrochemical characterization of ruthenium-based binary anodes (Ti/RuO2 − Sb2O4 and Ti/RuO2 − TiO2) prepared by different heating methods (laser, microwave, and furnace). The heating method and chemical composition were crucial in the anode characteristics and catalytic activity. The anodes of Ti/RuO2 − Sb2O4 composition prepared by laser and microwave show an increase in voltammetric charge by 1.4 and 1.9-folds and a decrease in resistance to charge transfer by approximately 2-folds compared with the corresponding furnace-made anode. The Ti/RuO2 − TiO2 anode prepared by unconventional methods (laser and microwave) shows an increased voltammetric charge in approximately 3-folds and reduced resistance to charge transfer at 5.6 and 3.4 times, respectively, compared with the anode prepared in an electric furnace. The composition of MMO and the applied current density are the main factors that influence the production of ClO and chloramine disinfectants. The highest electrocatalytic activity for generating hypochlorite from low-concentrated NaCl solutions was obtained by the Ti/RuO2 − TiO2 anode prepared by laser heating using a current density of 60 mA cm−2. Additionally, we evaluated the electrochemical generation of inorganic chloramines. Consequently, this study offers new insights into the preparation of low-cost materials for efficient in situ generation of disinfectants.

102 Application of Quantitative Mineralogy to Determine Sources of Airborne Particles at a European Copper Smelter

Abstract To ensure that regulatory compliance is maintained at mineral processing operations, worker exposure is regularly monitored. Determining the quantity and type of airborne particles permits the operation to identify the sources of dust, implement proper dust suppressant strategies, and ultimately, limit worker exposure. Conventional methods of analysis, such as chemical assay, are unable to rigorously differentiate between phases containing the same elements and may result in ambiguity related to identifying the source of airborne dust. A combination of Quantitative Evaluation of Materials by Scanning Electron Microscope (QEMSCAN) and chemical characterization has been used to evaluate personally taken size selective aerosol samples at key locations throughout a Cu smelter in Europe. Surface samples were also examined using higher resolution measurements. The Cu phases present in the workplace air samples are reflective of the activities performed at specific locations. Near the anode and electric furnace, the majority of Cu in the airborne dust is carried in metals and oxide phases (60-70%), and in the batch preparation area where Cu concentrate is received, significant amounts of Cu are carried in sulfide minerals (chalcocite, chalcopyrite/bornite, >40%). The results of the analysis will aid in the identification of the origin of emissions specific to location and activity, assist personnel in developing the appropriate mitigation strategies to limit workers exposure, and further understanding of the health risks associated with exposure. Additional metals of concern (e.g, Pb, As, and Cd) are also considered throughout this program. Speaker Biography Michelle Kelvin is a geoscientist and environmental mineralogist. She specializes in characterizing dust emissions that originate from industrial operations using modern geochemical methods and X-ray beam technologies.

Microwave heating to form porous TiO2 layer on high-haze FTO film for dye-sensitized solar cell

A porous TiO2 layer was formed on a fluorine-doped tinoxide (FTO) film using a microwave heating technique, and applied to a dye-sensitized solar cell (DSSC). Under microwave irradiation, a self-heating process was induced in the FTO film to raise the substrate temperature up to 600 °C within a minute. After 12 min of microwave irradiation of the porous TiO2/FTO double layer, the internal resistances at the TiO2/FTO interface and the TiO2 interparticles were effectively reduced. By tuning the haze of the optical transmission through the FTO film, the photovoltaic performance was enhanced, and the conversion efficiency reached values as high as 7.2% at a haze of 31.5%, which was attributed to effective light harvesting within the cell. Unique ionic diffusion induced under microwave irradiation was detected at a lower substrate temperature, and the cell that formed at a substrate temperature of 350 °C exhibited a conversion efficiency of 6.5%, which is high for the sintering temperature. Although the photovoltaic performance was comparable to that of a general DSSC, a rapid sintering process that reduced the internal resistance within the cell was demonstrated using a microwave heating technique. Compared with a conventional electric furnace, the microwave heating technique can produce ceramics with high densities in a short time, and is an ideal tool for producing DSSCs.

A Temperature Control Method of Electric Heating Furnace Based on Fuzzy PID

The traditional PID control method has a series of problems such as overshoot or static error. This paper takes the electric heating furnace temperature control system as the background, combines the fuzzy algorithm to design the fuzzy PID system, and uses the MATLAB fuzzy control box to set up the fuzzy reasoning system and the fuzzy rule table., and use the Simulink platform to build the temperature control system simulation model of ordinary PID and fuzzy PID, and verify the influence of parameters on the system.

Pharmaceutical Standardization of Muktashukti Bhasma and Muktashukti Pishti

Shukti is an important component of Sudhavarga, the most recent class in the subject of Rasa Shastra. According to the availability, two forms of Shukti have been stated in Rasa Shastra texts: Jalashukti and Muktashukti. Muktashukti is considered for the study. This study has tried to develop the standard operating process for manufacturing Muktashukti bhasma and Muktashukti pishti. Three batches of MSB & MSP were prepared from the purified Muktashukti. While manufacturing three batches same raw material and manufacturing instruments were used. Before processing for Bhasma or Pishti, the purification process is advocated for Muktashukti. Kanji (Rice gruel) was used for purification as per textual reference. Purified Muktashukti was levigated with Rose water to obtain Pishti. However, for Bhasma preparation, the Muktashukti was triturated with Aloe vera juice, and then heating was done in an Electric muffle furnace. 7 liters of Kanji was taken for 500g of Muktashukti Shodhana by Swedana for 3hrs in Dolayantra, with an average weight rise of 96.24% and a weight loss of 3.76% during the Shodhana method. During MSB preparation, a 10% loss was observed & 90% of Bhasma was obtained. However, in MSP preparation, a 12.14% loss was observed & 87.86% was obtained. This study will give the direction related to the duration of levigation and temperature regulation while Muktashukti Bhasma preparation. For Pishti preparation, the wet grinder was used, which will provide exact rotation and duration to obtain the proper pishti from Muktashukti.

Mineral Phase Reconstruction and Separation Behavior of Zinc and Iron from Zinc-Containing Dust.

Zinc-containing dust can be found in ironmaking and steelmaking, and it is an important secondary resource of zinc. Zinc-containing dust from an electric furnace was used as a raw material to study the phase transformation behavior of the dust using a calcification roasting process and the zinc-iron separation behavior by using ammonia leaching. The zinc-bearing dust was mixed with CaO and roasted to transform the zinc ferrite into zinc oxide. The results showed that increasing the calcium oxide to dust ratio could promote the conversion of zinc ferrite to zinc oxide. When the calcium oxide ratio reached 60%, the peak of zinc ferrite in the calcined-roasted product in the zinc-containing dust basically disappeared. As the temperature increased, the zinc oxide grains increased but were still smaller than 10 µm. The calcined-roasted product was crushed and ground, and the zinc was leached by ammonia. A zinc-iron recovery rate of 86.12% was achieved by the ammonia leaching. The leachate could be used for zinc extraction by electrolysis. The leaching residue was mainly calcium ferrate, which could be used in sintering production. The proposed process may achieve on-site recovery of zinc-containing dust in steel-making plants.

FABRICATION OF GRANULATED FOAM GLASSES FOR LIGHTWEIGHT CONCRETE APPLIED FOR THERMAL AND SOUND INSULATION

Granulated foam glass aggregates were fabricated and applied as fillers in lightweight concrete. Soda lime silicate based glass was used as the main raw material in the foam glass process. Firing temperatures in the range of 820-850ºC were suitable for the foaming process. Granulation was processed using a rotary granulator and heated to expand in an electric rotary furnace. Foaming at 840ºC showed overall properties suitable for applying as a filler in lightweight concrete fabrication e.g. low density, high porosity, uniform of pore size. Foam glass granules processed at 840ºC were mixed with cement paste in the ratios of 5, 10, 15, and 20 vol% to study for bulk density, compressive strength, thermal conductivity, thermal resistivity and sound absorption. Overall, increasing foam glass content in concrete caused a decrease in bulk density, compressive strength and thermal conductivity coefficient. In contrast, thermal resistance and sound absorption coefficient of the foam glass filled lightweight concretes improved significantly.

Influence of Impurity Morphology on the Fatigue Strength of High-Purity Structural Steel Melted in an Electric Furnace

A modern user requires low operating costs, but also reliability from machines and technical devices. Reliability during the service life depends on the quality of construction solutions, but also largely on the quality, properties and adaptation to the working conditions used in the construction of construction materials. During the operation of technical objects, their a highly predictable wear occurs. The problem is the phenomena of premature wear and damage of elements. The causes of failure of technical facilities are usually complex and depend on many factors. They can include the human factor and the one related to the quality, selection, production and technological processes of the materials used in the construc-tion of the facility. In real technical facilities, many premature failures are caused by material fatigue, which is related to the quality and distribution of impurities in the material. The paper presents the change in fatigue strength for rotational bending of low-carbon structural steel hardened and tempered at different temperatures as the effect of the size and distance between impurities on the fatigue strength of high-quality carbon structural steel melted in the industrial conditions in an electric arc furnace.

Effect of Refined Spheroidizated Structure on Mechanical Properties of Spring Steel 51CrV4

The steel 51CrV4 is widely used for production of springs. Materials research into spring steels aims to meet the requirements of industry, which mainly concern high yield and tensile strengths. Ductility has to be retained as the strength is increased. Also, the resistance against brittle fracture is im-portant, measured as fracture toughness. Enhancement of the mentioned mechanical properties can be accomplished by structural refinement. One possible way to refine the final quenched and tem-pered structure is to refine the soft annealed structure before quenching. The article is devoted to the Accelerated Carbide Spheroidisation and Refinement (ASR) with a comparison to conventional soft annealing (SA) in the 51CrV4 spring steel. Both spheroidization treatment (ASR by induction heating, SA by electric furnace) led in different carbide particle sizes. The carbide refinement alters the mate-rial’s behaviour during quenching. Finer carbides dissolve more rapidly during austenitization at the quenching temperature. It is possible to lower the quenching temperature thanks to carbide refine-ment. Mechanical properties after hardening with different quenching temperatures were positively affected too.

Comparison of Thermal and Laser-Reduced Graphene Oxide Production for Energy Storage Applications.

A way to obtain graphene-based materials on a large-scale level is by means of chemical methods for the oxidation of graphite to obtain graphene oxide (GO), in combination with thermal, laser, chemical and electrochemical reduction methods to produce reduced graphene oxide (rGO). Among these methods, thermal and laser-based reduction processes are attractive, due to their fast and low-cost characteristics. In this study, first a modified Hummer's method was applied to obtain graphite oxide (GrO)/graphene oxide. Subsequently, an electrical furnace, a fusion instrument, a tubular reactor, a heating plate, and a microwave oven were used for the thermal reduction, and UV and CO2 lasers were used for the photothermal and/or photochemical reduction. The chemical and structural characterizations of the fabricated rGO samples were performed by Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), scanning electron microscope (SEM) and Raman spectroscopy measurements. The analysis and comparison of the results revealed that the strongest feature of the thermal reduction methods is the production of high specific surface area, fundamental for volumetric energy applications such as hydrogen storage, whereas in the case of the laser reduction methods, a highly localized reduction is achieved, ideal for microsupercapacitors in flexible electronics.

DEVELOPMENT AND IMPLEMENTATION OF AN EFFECTIVE METHOD FOR MANAGING SELENIUM DISTRIBUTION IN THE TECHNOLOGY OF SULFATE LEACHING OF FUSED PRODUCTS AT "THE NORILSK NICKEL HARJAVALTA OY" ENTERPRISE

The nickel refining company "Norilsk Nickel Harjavalta Oy" (NNH) produces three main types of nickel products: cathode nickel, nickel powders (briquettes), nickel salts. The decisive role in achieving high performance and guaranteed quality the nature of the impurities distribution and their behavior control, in particular selenium, plays a role in nickel products. Selenium has a sharply negative effect on the process of obtaining a cathode nickel base. At elevated concentrations in nickel-cobalt solution, this impurity makes it impossible to stable obtain commercial nickel cathodes. The study of the selenium behavior patterns in the processing circuit of metallurgical intermediates, such as feinstein and stein of electric slag-cleaning furnace (ESCF), made it possible to make the necessary changes to the technological scheme of the NNH leaching shop and to clarify the operating parameters of the main operations. A hypothesis is proposed about the possible mechanism of the effect of metallized fraction (alloy) contained in the feedstock on the process of reducing Se6+ to Se4+. The experiments performed confirmed the direct dependence of the selenium deposition degree from the solution to the solid precipitate from the alloy content in the feedstock. It has been established that by combining the applied ESCF matte with feinstein and/or nickel concentrate (NC) from feinstein separation, it is possible to effectively control the distribution of selenium in NNH technology, preventing its critical concentrations in nickel catholyte. Based on the research results, a two-flow scheme for processing processed products has been implemented, in which it is envisaged to use a combination of NC and products with a high content of metallized fraction. This method allowed to minimize the concentration of selenium in nickel catholyte.