Smelting Temperature Research Articles

Investigation into the Fabrication Possibility of the Boron–Aluminum Sheet Rolling of Increased Strength without Using Homogenization and Quenching

Al–Cu–Mn (Zr) aluminum alloys possess high strength and manufacturability without operations of thermal treatment (TT). In order to investigate the fabrication possibility of the aluminum boron-containing alloy in the form of sheet rolling with an increased strength without TT, Al–2% Cu–1.5% Mn–2% B and Al–2% Cu–1.5% Mn–0.4% Zr–2% B alloys are prepared. To exclude the precipitation of refractory boride particles, smelting is performed in a RELTEK induction furnace providing intense melt stirring. The smelting temperature is 950–1000°C. Pouring is performed into graphite molds 40 × 120 × 200 mm in size. It is established using computational methods (Thermo-Calc) that manganese forms complex borides with aluminum and zirconium at the smelting temperature; herewith, a sufficient amount of manganese remains in liquid, while zirconium is almost absent. The formation of AlB2Mn2 complex boride is proven; however, the amount of manganese remaining in the solid solution is sufficient to form the particles of the Al20Cu2Mn3 phase in amounts of up to 7 wt %. Boron stimulates the isolation of Al3Zr primary crystals in the alloy with zirconium; in connection with this, an amount of zirconium insufficient for hardening remains in the aluminum solid solution. The possibility of fabricating thin-sheet rolling with a thickness smaller than 0.3 mm with homogeneously distributed accumulations of the boride phase with a particle size smaller than 10 μm is shown. A high strength level (up to 543 MPa) is attained without using quenching and aging due to the precipitation of dispersoids of the Al20Cu2Mn3 phase during hot deformation (t = 450°C).

Thermodynamic model of metallothermic smelting of ferromolybdenum

ABSTRACTFerromolybdenum, used in alloy steel production, is made by the batch reduction of molybdenum oxide by silicon and aluminium at high temperatures. In this work, the technology of the process has been reviewed and representative charge mixes compared. A computational thermodynamics model was developed and used to investigate the relationships between charge composition and ferroalloy grade and quality, indicated by its silicon content. The model predicted satisfactorily the composition of the ferromolybdenum and waste slag from a typical charge mixture. The silicon content depended on the ratio of silicon to molybdenum oxide in the charge and was not sensitive to the assumed smelting temperature or activity coefficient of silicon in the alloy. Losses of molybdenum to slag as dissolved oxide were predicted to be much lower than published industrial data, suggesting that losses in practice are mostly due to the inclusion of unsettled ferromolybdenum droplets.

Investigation into the Possibility of Fabricating Boraluminum Rolling of Increased Strength without Homogenization and Quenching

Aluminum alloys of the Al–Cu–Mn (Zr) system possess high strength and manufacturability without heat treatment (HT). In order to investigate the possibility of fabricating an aluminum boron-containing alloy in the form of sheet rolling with increased strength without the HT, Al–2% Cu–1.5% Mn–2% B and Al–2% Cu–1.5% Mn–0.4% Zr–2% B alloys are prepared. To exclude the deposition of refractory boride particles, smelting is performed in a RELTEK induction furnace providing intense melt stirring. The smelting temperature is 950–1000°C. Pouring is performed into 40 × 120 × 200 mm graphite molds. It is established using computational methods (Thermo-Calc) that manganese forms complex borides with aluminum and zirconium at the smelting temperature and a sufficient amount of manganese remains in liquid, while zirconium is almost absent in it. The formation of AlB2Mn2 complex boride is proved experimentally (scanning electron microscopy and micro X-ray spectral analysis), but the amount of manganese remaining in the solid solution is sufficient to form particles of the Al20Cu2Mn3 phase in an amount reaching 7 wt %. Boron in the zirconium-containing alloy stimulates the isolation of primary crystals Al3Zr, in connection with which an insufficient amount of zirconium remains in the aluminum solid solution for strengthening. The possibility of fabricating thin-sheet rolling smaller than 0.3 mm in thickness with uniformly distributed agglomerations of the boride phase with a particle size smaller than 10 µm is shown. A high level of strength (up to 543 MPa) is attained with no use of quenching or aging due to the isolation of dispersoids of the Al20Cu2Mn3 phase during hot deformation (t = 450°C).

Solution behavior of ZnS and ZnO in eutectic Na2CO3−NaCl molten salt used for Sb smelting

The solution behavior, including solubility, reactivity and sedimentation, of ZnO and ZnS in a Na2CO3−NaCl molten salt used for Sb smelting was investigated in the temperature range of 700-1000 oC. The saturated amount of dissolved ZnO in the molten salt remained constant at 0.02% and was unaffected by temperature; additionally, ZnO did not react with the molten salt. In contrast, the saturated amount of dissolved ZnS in the eutectic molten salt increased with increasing temperature, and the content of ZnS was 0.53% at 1000 oC. In addition, ZnS reacted with Na2CO3 above 900 oC to give ZnO. The sedimentation rates of these three species in the molten salt followed the order of Sb>ZnS>ZnO. It was thus concluded that ZnO is an appropriate sulfur-fixing agent for low-temperature Sb smelting in a Na2CO3−NaCl molten medium, and that the optimal smelting temperature is below 900 oC.

Pollution prevention and control measures for the bottom blowing furnace of a lead-smelting process, based on a mathematical model and simulation

One of the outstanding environmental protection problems of lead smelting enterprise at present is that the large amount of generation and emissions of flue gas and dust contaminated with heavy metals, particularly uncontrolled emissions (such as dissipation of dust). In order to solve the mentioned problem, this article takes the lead smelting process as the research object, and develops a mathematical model to simulate the production process of lead smelting. The model, which is commonly used in the production practice of metallurgical industry, is improved and verified in this article to simulate the output of products and pollutants under different operational conditions. The developed model was applied to simulate a bottom blowing furnace in a lead-smelting plant with 1 t of input materials fed in at a continuous normal production level, and verified by measured data from the actual production. Further simulation was carried out to analyze the influences of different reaction parameters, such as the composition of input materials, smelting temperature, and oxygen enrichment (input oxygen amount) on the output constituents, and Pb behavior among the various phases, particularly in flue gas. The results show that when the total content of Pb and S in the input materials, and other operational parameters, are constant, a Pb content of 52–62% in the input materials will be beneficial for reducing the Pb amount in flue gas as well as increasing the output amount of lead bullion. When the composition (species and content) of input materials and oxygen enrichment are constant, a lower temperature is more advantageous to reduce the Pb amount in the flue gas. When the composition (species and content) of the input materials and the smelting temperature are constant, the Pb amount of the gas and the flue gas will be reduced significantly if the input oxygen amount is larger than 90 m3/t-input materials. Finally, the most suitable operational scheme for the higher production efficiency and fewer pollutant generation amounts are discussed and suggested.

Two-stage reduction for the preparation of ferronickel alloy from nickel laterite ore with low Co and high MgO contents

The preparation of ferronickel alloy from the nickel laterite ore with low Co and high MgO contents was studied by using a pre-reduction–smelting method. The effects of reduction time, calcination temperature, quantity of reductant and calcium oxide (CaO), and pellet diameter on the reduction ratio of Fe and on the pellet strength were investigated. The results show that, for a roasting temperature >800 °C, a roasting time >30 min, 1.5wt% added anthracite coal, 5wt% added CaO, and a pellet size of ~10 mm, the reduction ratio of Fe exceeds 70% and the compressive strength of the pellets exceeds 10 kg per pellet. Reduction smelting experiments were performed by varying the smelting time, temperature, quantity of reductant and CaO, and reduction ratio of Fe in the pellets. Optimal conditions for the reduction smelting process are as follows: smelting time, 30–45 min; smelting temperature, 1550°C; quantity of reductant, 4wt%–5wt%; and quantity of CaO, 5wt%; leading to an Fe reduction ratio of 75% in the pellets. In addition, the mineral composition of the raw ore and that during the reduction process were investigated by process mineralogy.

Efficient Utilization of Nickel Laterite to Produce Master Alloy

To lower the smelting temperature associated with the carbothermic reduction processing of laterite, the optimization of slag and alloy systems was investigated to enable the reduction of laterite ore in the molten state at 1723 K. The master Fe-Ni-Mo alloy was successfully produced at a lower temperature (1723 K). The liquidus of the slag decreased with the addition of oxide flux (Fe2O3 and CaO) and that of the ferronickel alloy decreased with the addition of Mo/MoO3. More effective metal–slag separation was achieved at 1723 K, which reduces the smelting temperature by 100 K compared with the current electric furnace process. A small addition of Mo/MoO3 not only decreased the melting point of ferronickel alloys but also served as a collector to aggregate the ferronickel sponges allowing them to grow larger. The FeO concentration in the slag and the nickel grade of the alloy decreased with increasing graphite reductant addition.

One-Step Extraction of Antimony in Low Temperature from Stibnite Concentrate Using Iron Oxide as Sulfur-Fixing Agent

A new process for one-step extraction of antimony in low temperature from stibnite concentrate by reductive sulfur-fixation smelting in sodium molten salt, using iron oxide as sulfur-fixing agent, was presented. The influences of molten salt addition and composition, ferric oxide dosage, smelting temperature and duration on extraction efficiency of antimony were investigated in details, respectively. The optimum conditions were determined as follows: 1.0 time stoichiometric requirement (α) of mixed sodium salt (αsalt = 1.0), WNaCl:Wsalt = 40%, αFe2O3 = 1.0, Wcoke:Wstibnite = 40%, where W represents weight, smelting at 850 °C (1123 K) for 60 min. Under the optimum conditions, the direct recovery rate of antimony can reach 91.48%, and crude antimony with a purity of 96.00% has been achieved. 95.31% of sulfur is fixed in form of FeS in the presence of iron oxide. Meanwhile, precious metals contained in stibnite concentrate are enriched and recovered comprehensively in crude antimony. In comparison to traditional antimony pyrometallurgical process, the smelting temperature of present process is reduced from 1150–1200 °C (1423–1473 K) to 850–900 °C (1123–1173 K). Sulfur obtained in stibnite is fixed in FeS which avoids SO2 emission owing to the sulfur-fixing agent. Sodium salt can be regenerated and recycled in smelting system when the molten slag is operated to filter solid residue. The solid residue is subjected to mineral dressing operation to obtain iron sulfide concentrate which can be sold directly or roasted to regenerate into iron oxide.

Preliminary study on zinc smelting relics from the Linjiangerdui site in Zhongxian County, Chongqing City, southwest China

The study of zinc distillation technology in ancient China has recently been published by Zhou et al. 2012, 2014. From these two papers we know more detail informations about it. But, there are still some key technologies we do not know exactly. The first question is if there is any difference between the coal used as fuel or as reductant agent? We also don't know the exact smelting temperature in this kind of smelting activity. The last and most important thing, we know that the retorts were charged with zinc ores, coal and charcoal, but we know little about the exact ration between them. In order to solve these questions, this paper presents the analytical study by OM, XRF, XRD, DIL and SEM-EDS of zinc production that remains from the archaeological site of Lijiangerdui, in the same region, dated to the Ming dynasty, probably a few years earlier than the previous studies. The results indicated that there are different coals used for the smelting activity, and the smelting temperature can be as high as 1306°C, all of these are over 1180°C. The ratios for the raw material may be 1:2.7 [(coal+charcoal)/zinc ores].

Reductive smelting of spent lead–acid battery colloid sludge in a molten Na2CO3 salt

Lead extraction from spent lead–acid battery paste in a molten Na2CO3 salt containing ZnO as a sulfur-fixing agent was studied. Some influencing factors, including smelting temperature, reaction time, ZnO and salt dosages, were investigated in detail using single-factor experiments. The optimum conditions were determined as follows: T = 880°C; t = 60 min; Na2CO3/paste mass ratio = 2.8:1; and the ZnO dosage is equal to the stoichiometric requirement. Under the optimum conditions, the direct recovery rate of lead reached 98.14%. The results suggested that increases in temperature and salt dosage improved the direct recovery rate of lead. XRD results and thermodynamic calculations indicated that the reaction approaches of lead and sulfur were PbSO4→Pb and PbSO4→ZnS, respectively. Sulfur was fixed in the form of ZnS, whereas the molten salt did not react with other components, serving only as a reaction medium.

Research on the Temperature Parameters in Casting-rolling Continuously Forming of Ring Parts

Based on the complicated process,caused seriously waste of material and energy in traditional production process of rings,the objective of this study is to put forward a new type of ring production process,casting-rolling continuously forming of rings,as well as the temperature of each process through theoretical analysis,numerical simulation and experimental research.42 CrMo alloy steel is used as the material of the rings,the phase diagram of 42 CrMo steel alloy is made through JMatPro software.According to the solidification process of phase change and industrial production practice to accurate formulate the smelting temperature and the smelting temperature is 1 750 ℃.The pouring temperature and the mold stripping temperature of centrifugal casting are simulated by the numerical simulation of microstructure and analysis on process of setting on ProCAST software,which concentrates on grain size,temperature and stress variation during casting,the pouring temperature is 1 520 and the mold stripping temperature is 1℃ 050 ℃.The hot stage experiment is employed to seek the change process of dynamic organization grain that accurate prediction the holding mold temperature and time,the temperature is 1 000 ℃and the time is 180 min.The simulation result is consistent with industrial production,the hot stage microscope shows fine and homogeneous microstructure of the samples,meets the grain condition of hot rolling.

A Preliminary Study of Furnace Materials from Shuiquangou Iron Smelting Site of Liao and Jin Period in Beijing

Microstructure, chemical composition, physical property and high temperature process of furnace materials from Shuiquangou site were analyzed in order to promote an exploratory scientific study on cast iron smelting furnace materials in ancient China. The results showed that raw materials were locally collected and gone through a screened process; there were at least two productions of furnace lining which used in different parts of the furnace. Furnace materials can provide enough Na2O, Al2O3, and SiO2 into slags. The refractoriness of them were about 1200–1300°C, and the smelting temperature was among 1300–1500°C.

Thermodynamic Research of Boron Oxide Reducing with Carbothermic Method

Based on the phase diagrams analysis, the activity model of Fe-C-B ternary system was established with the ion and molecule coexistence theory. The activities of Fe, C, B, Fe3C, FeB, FeB2 and B4C in melt were calculated by analyzing the model. We have researched the thermodynamic condition of boron oxide reducing with carbothermic method and analyzed the effects of CO partial pressure, B2O3 content and slag type for the lowest smelting temperature. In normal pressure, the carbon content is high in melt, so it needs 2000°C for decarbonizing and chrome remaining. When CO partial pressure is 0.1 kPa and CaO content is less 60%, the lowest temperature of smelting ferro boron could be below 1600°C.

KODOS 망간단괴의 SiO2-CaO-MnO 상관관계와 분포양상

<TEX>$SiO_2$</TEX> and CaO are added to decrease the smelting temperature in the reduction-smelting method for manganese nodule processing. These elements are components of the manganese nodules and might be very important controlling factors in the processing due to the locally variable content. The 707 chemical data of manganese nodules acquired from 1994 to 2001 in KODOS(Korea Deep Ocean Survey) area were used for the hierarchical cluster analysis. The chemical data were classified by the morphological types, and the averages of the chemical data for each station were classified by the facies groups and the localities. All data are plotted on the <TEX>$SiO_2-CaO-MnO$</TEX> phase diagram at <TEX>$1773^{\circ}K$</TEX> to compare with the best compositional area in the nodule smelting. Variations and distributions of <TEX>$SiO_2$</TEX> and CaO in KODOS nodules were also reviewed. The mineral phases assigned by the cluster analysis are CFA(Carbonate Fluorapatite), Fe-oxide, Al-silicate, and Mn-oxide. MnO contents are generally higher than <TEX>$SiO_2$</TEX> contents in most of the morphological types except for the Is- and It-type. The Dt- and Tt-type show wider range and the E-types show high anomaly in their CaO contents. The stations which belong to facies group A and B show generally higher MnO contents than <TEX>$SiO_2$</TEX> contents, however, the stations of facies group C and D show wide range in their MnO and <TEX>$SiO_2$</TEX> contents. It seems to be very important to control the <TEX>$SiO_2$</TEX> contents in the processing because of the wide range in the northern area. The additions of approximately 10 wt.% CaO and 10 wt.% <TEX>$SiO_2$</TEX> are recommended for the northern area, whereas, the additions of approximately 10 wt.% CaO and 20 wt.% <TEX>$SiO_2$</TEX> are recommended for the southern area.

Modelling of ferrosilicon smelting in submerged arc furnaces

Ferrosilicon alloys are commonly manufactured in submerged electric arc furnaces with little slag. In the presence of iron, silica will be reduced by carbon to give a maximum of ~ 22 wt% silicon in the liquid alloy. The rest of the carbon will be consumed to transform silica to silicon carbide at ~ 1810 K. Higher grades of ferrosilicon alloy may be produced owing to the reactions occurring between silicon carbide and silica at temperatures above 1810 K. Thermodynamic data on the standard free energy of formation of species are used in the study to calculate the required smelting temperatures at various silicon contents of the alloy. The sum of partial pressures of carbon monoxide and silicon monoxide must equal the applied pressure of 1 atm at the smelting temperature. It is important to know the activity coefficient of silicon in the alloy as a function of temperature, and the silicon content of the alloy using literature data. Mass and enthalpy balances are used to determine the carbon and electricity requirements of the process. The recycling of silicon monoxide is promoted by maintaining a bed of a certain height so that evolved gases are cooled owing to heat exchange between the gas and solid phases. It might result in a saving of more than 3000 kWh/t of Fe-80Si alloy. The reduction of silica is found to account for just 47·6% of the total energy that is added via the calorific value of carbon and the electricity in producing the alloy. Further improvement in the performance is visualised by reducing electrical losses and recovering as much as possible the calorific value of outgoing carbon monoxide.

A thermodynamic model of nickel smelting and direct high-grade nickel matte smelting processes: Part II. distribution behaviors of Ni, Cu, Co, Fe, As, Sb, and Bi

A thermodynamic model has been developed to predict the distribution behavior of Ni, Cu, Co, Fe, S, As, Sb, and Bi in nickel smelting and direct high-grade nickel matte smelting processes. The model has been validated by numerous experimental data and industrial data with a wide range of operating conditions. The effect of operating conditions on the distributions of Ni, Cu, Co, As, Sb, and Bi among the gas, matte, and slag phases has been investigated. It was found that the distribution behavior of Ni, Co, Cu, As, Sb, and Bi in the nickel smelting furnace depends on process parameters such as the smelting temperature, matte grade, oxygen enrichment, Fe/SiO2 ratio in the slag, Cu/Ni ratio in charge, and oil/air ratio. The parameters also have an influence on the behavior of Fe3O4 in the slag.

A thermodynamic model of nickel smelting and direct high-grade nickel matte smelting processes: Part I. Model development and validation

A thermodynamic model has been developed to predict the distribution behavior of Ni, Cu, Co, Fe, S, As, Sb, and Bi in the Outokumpu flash-smelting process, the Outokumpu direct high-grade matte smelting process, and the INCO flash-smelting process. In this model, as many as 16 elements (Ni, Cu, Co, Fe, As, Sb, Bi, S, O, Al, Ca, Mg, Si, N, C, and H) are considered, and two nickel sulfide species are used to allow for modeling of sulfur-deficient mattes. The compositions of the matte, slag, and gaseous phases in equilibrium are calculated using Gibbs free energies of formation and the activity coefficients of the components derived from the experimental data. The model predictions are compared with the known industrial data from the Kalgoorlie Nickel Smelter (Kalgoorlie, Australia), the Outokumpu Harjavalta Nickel Smelter (Harjavalta, Finland), the INCO Metals Company (Sudbury, Canada), and from a number of experimental data. An excellent agreement is obtained. It was found that the distribution behaviors of Ni, Co, Cu, Fe, S, As, Sb, and Bi in the nickel smelting furnace depend on process parameters such as the smelting temperature, matte grade, and partial pressure of oxygen in the process.

Tellurium distribution in copper anode slimes smelting

Tellurium is a common minor constituent of copper anode slimes. The distribution of tellurium between the phases during slimes smelting is an important consideration, both in terms of metal quality and the capture of the oxidized tellurium. In this work, the oxidation by oxygen at 1100 °C of a silver-copper selenide matte containing 2 pct tellurium has been examined. The distribution of tellurium between the phases was determined as the extent of oxidation increased, and the system was modeled using a computational thermodynamics package. Oxidized tellurium was found to report to the slag, with none being removed with the gas. The thermodynamic model predicted, to an acceptable level, the tellurium content of all phases as oxidation progressed. It was used to show that oxidation by air rather than oxygen results in higher residual tellurium levels in silver metal and that the lower the smelting temperature, the greater the extent of tellurium elimination from silver to the slag.

Distribution study of priority pollutant PAHs from a laboratory aluminum-can chip smelting furnace

In this article, the effect of smelting temperature on the distribution of poly aromatic hydrocarbon (PAH) species in the flue gas streams from a bench-scale laboratory aluminum-can-chip smelting furnace under pyrolytic conditions is examined. The preset smelting temperatures are 600, 700, and 800°C. Both solid-phase and gas-phase PAHs were sampled, extracted, concentrated, and analyzed using GC/FID and GC/MS. Results indicate that increasing furnace temperature increases the species number, average molecular weight, and total concentration of PAHs. Each of the observed PAHs was much more associated with soot particles (i.e., referring as the solid-phase PAHs), compared with what stayed in gaseous form (i.e., the gas-phase PAHs). Further, with the exception of fluoranthene, each PAH's partial pressure in the sampled flue gas stream was much less than its own vapor pressure (i.e., at 25°C). It is proposed that most PAHs are instantaneously wrapped in by the growing soot particles once formed under pyrolytic conditions at high smelting temperatures, thus resulting in the significant difference between each PAH's partial pressure in flue gases and its vapor pressure.

The soda ash smelting of lead-acid battery residue

Abstract A pyrometallurgical process for the recovery of lead from battery residue was investigated. The process involved pelletizing the residue with sodium carbonate follwed by a carbothermic smelting operation. The overall in the process is as follows: PbSO4(s) + Na2CO3(s) + C(s) = Pb(1) + CO(g) + CO2(g) + Na2 SO4 The sulphur dioxide emissions are minimal since the sulphur is fixed in the slag as sodium sulphate. Lead emissions are considerably reduced due to the use of pellets and a lower smelting temperature. The optimum conditions for the maximum recovery of lead were determined. These were: a smelting temperature of 1223 K, a charcoal addition of 3 mass% and a sodium carbonate addition of 20 mass percent. A moisture addition of 10 mass% during pelletizing was found to be sufficient to complete the sulphate-carbonate exchange reaction and to produce a strong green pellet. Sintering of the green pellets prior to reduction was found to have no effect on the lead recovery. However, a minimum in the strength and abrasion resistance of the pellets occurred at 773K. Lead recoveries of 96–98% were achieved and the lead content of the slag was in the range of 1–2 mass%.