Optimum Roasting Conditions Research Articles

Optimization of Roasting Conditions for Preservation of Nutritional Quality of Terminalia catappa Almonds by Response Surface Methodology

The optimal roasting conditions (temperature and time) of Terminalia catappa (TC) almonds allowing to preserve the nutritional quality of their almonds and oils were investigated. The almonds roasted at different temperature (80-120 °C) for various time (30-60 min) using response surface methodology and oils extracted were analyzed. Effect of temperature and time on antinutritional factors and the nutritional quality of almonds and oils was evaluated then the optimum roasting conditions was determined. Results showed that oxalates, tannins and phytates contents of roasted almonds were significantly (P<0.05) influenced by the temperature and time. Roasting had a significant effect on oxidative stability and some quality index of oils. The optimal roasting conditions for reduction of antinutritional factors in almonds were 89.91 °C and 60 min with 70.37% as desirability. However, the results indicate that TC almond could be used in several areas of the food industries.

Roasting of a Low-Grade Goethite Ore Using Horse Residue and Its Beneficiation by Magnetic Separation

In the present study, the use of horse residue as an alternative reducing agent in the roasting of a low-grade goethite ore containing 17.60% Fe was investigated. Additional roasting experiments were carried out with corn starch and without reducing agent for comparison. Each roasted product was characterized using X-ray diffraction (XRD) and magnetic hysteresis (MH) loops analyses. The optimum roasting conditions (roasting temperature [400, 500, and 600 °C], reducing agent/ore ratio [0.04, 0.08, and 0.12], and roasting time [10, 20, and 30 min]) were investigated based on the Taguchi approach. The magnetic susceptibilities of the roasted sample with the addition of reducing agents were higher compared to that of the roasted sample in the absence of reducing agent. Experimental findings indicate that the horse residue can be used as the reducing agent. Finally, an iron ore concentrate assaying a Fe grade of 62.12% with a recovery of 56.93% was prepared using wet magnetic separation at a magnetic intensity of 0.5 T from the ore roasted under the following roasting conditions: roasting temperature of 500 °C, reducing agent/sample ratio of 0.08, and roasting time of 30 min.

Iron recovery from refractory limonite ore using suspension magnetization roasting: A pilot-scale study

Limonite ore is a potentially important iron resource and widely distributed in the world. However, it is difficult to process by traditional methods due to the high water content and fine dissemination of aluminum and silica. In this paper, typical refractory limonite ore was studied by suspension magnetization roasting and magnetic separation technology. According to the pilot-scale study, optimum roasting conditions were determined as a capacity of 120 kg/h, CO dosage of 6.5 m3/h, N2 dosage of 9.5 m3/h, roasting temperature of 460 °C, and gas flow of 16.0 m3/h. An iron concentrate with Fe grade of 64.97% and recovery of 94.53% was obtained using a suspension magnetization roasting – grinding – magnetic separation process. The material and roasted products were characterized by X-ray diffraction (XRD), mineral liberation analyzer (MLA), and backscattered electron (BSE) analyses. The results indicated that the iron oxide phase transformation was as follows goethite → hematite → magnetite → maghemite. The mineral dissemination analysis showed that fine grinding and magnetic separation was favorable to improve the quality of iron concentrates. However, some Al and Si were difficult to remove due to the isomorphism. The suspension magnetization roasting is feasible in economic terms, and the cost of magnetization roasting is $8 per ton. This technology will not only increase the available iron ore resource reserves but also alleviate the imbalance between supply and demand of iron ore in China.

Effect of Roasting on the Phytochemical Properties of Three Varieties of Marble Vine (Dioclea reflexa) Using Response Surface Methodology.

This study assessed the optimum roasting conditions on the phytochemical properties of three varieties of Dioclea reflexa seeds using response surface methodology. Roasting conditions were varied using temperature (110°C~200°C) and time (10~40 min). Phytochemical components (phenolics, tannin, flavonoids, cardiac glycoside, and steroids) of the seeds were screened and estimated. The study showed that availability of phytochemical activities was heat-dependent. An increase in roasting temperature beyond 110°C for 10 min resulted in a decrease in total phenolic (TP) and flavonoid (TF) contents. However, prolonged durations of roasting favored increased amounts of TP and TF in dark and light varieties. Total sterol, tannin, and cardiac glycoside contents increased with increasing roasting temperature and time. The desirability of the models were 0.76, 0.74, and 0.72 for black, dark brown, and light brown, respectively. The coefficients of regression (R2), ranged from 0.66 to 0.98 signifying accuracy of the model. The following models (cubic, quadratic, and 2 factor interaction) were significant (P≤0.05). We found that roasting time influenced the phytochemical properties of D. reflexa to a greater extent than temperature. The optimum roasting temperature and time was found to beat 110°C, 35 min, 40 min, and 32 min in black, dark brown, and light brown varieties, respectively. Roasting conditions significantly affects the phytochemical contents of three varieties of D. reflexa seed flour (P<0.05). Therefore, D. reflexa holds the potential to be used in development of functional foods and in therapeutic applications to promote health.

Extraction of lithium, rubidium and cesium from lithium porcelain stone

The anticipated increase in demand for Li, Rb, and Cs raises growing concern due to the expected shortage in alkali metals available for extraction from ores. In this study, two kinds of additives (Na2SO4 and CaCl2) were used to selectively extract alkali metals from lithium porcelain stone. HSC modelling was used to simulate the process of roasting the ore in the presence of these additives, and to predict the temperature effect in addition to the ore/Na2SO4/CaCl2 mass ratio. Under the optimized conditions, the Li, Na, K, Rb, and Cs extraction efficiencies were 98.70, 49.80, 37.90, 97.27, and 98.40%, respectively. The optimal roasting conditions were found to be an ore/Na2SO4/CaCl2 mass ratio of 1/0.2/0.2 with heating at 850 °C for 60 min, while the optimal water leaching conditions were a liquid/solid ratio of 1/1 and a stirring speed of 300 rpm at room temperature for 60 min. Upon analysis of the calcined and leaching residues, the extraction mechanism was demonstrated to involve a highly chemoselective ion-exchange process between the alkali metals present in the ore, the Na+ in Na2SO4, and the Ca2+ in CaCl2. After this process, the concentrations of the alkali metals in lixivium were approximately 3.43 g/L Li, 25.50 g/L Na, 11.00 g/L K, 1.35 g/L Rb, and 0.56 g/L Cs, thereby indicating the feasibility of this process.

Optimum roasting conditions of argan kernels (Argania spinosa L.) for the production of high-quality edible argan oil.

Roasting is an important step in the production of edible argan oils. The effect of argan kernel roasting temperature (ranging from 150 to 200°C) and time (from 10 to 50min), on oil yield, contents in total phenolic compounds, α- and γ-tocopherol, and oxidative stability, was researched using response surface methodology. Increases in roasting temperature and time have a significant effect on all the responses. This study showed that the optimum roasting conditions of argan kernel (indirect heat by convection) for the production of edible argan oils were 150°C and 50min, which allowed reaching a maximum oil yield of 32.45%. Edible argan oil, obtained under these conditions, had a content of total phenolic compounds of 78.01mg/kg, α- and γ-tocopherol of 30.28 and 495.03mg/kg, respectively, and an oxidative stability of 37.58h. Furthermore, it presented olfactory notes of 'almond, dried fruits, hazelnut and waffle', with 'sweet' and 'fruity' as positive attributes, without any defect.

Effect of microwave irradiation and conventional calcification roasting with calcium hydroxide on the extraction of vanadium and chromium from high-chromium vanadium slag

A novel high-efficiency method based on microwave irradiation roasting has been proposed to extract valuable metals from minerals. In this study, we employed microwave irradiation and conventional roasting for extracting vanadium and chromium from high-chromium vanadium slag (HCVS) with the additive calcium hydroxide. Differential thermal-thermogravimetry analysis (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy analysis (SEM-EDS), particle size distribution analysis and chemical analyses were used for the characterization and analysis to explain the mechanism of the roasting process. The results shown that roasting temperature, the m(CaO)/m(V2O5) ratio, and roasting time roasted by microwave irradiation and muffle furnace had significantly effect on extraction ratio of vanadium while the effect on the extraction ratio of chromium was relatively small. For the same roasting temperature, the degree of oxidation of HCVS roasted by microwave irradiation was higher than that roasted by muffle furnace. When the m(CaO)/m(V2O5) ratio is low, Mn4V2O9 and CaV2O6 are formed; with the m(CaO)/m(V2O5) ratio increased, Mn4V2O9 and CaV2O6 gradually converted to CaV2O7, and CaCrO3 is formed. Microwave irradiation decreased the particles size and shortened the roasting time. The optimal roasting conditions was determined to be: roasting temperature of 850 °C, m(CaO)/(V2O5) ratio of 0.95, and roasting time of 1.5 h. The maximum extraction ratio of vanadium and chromium roasted by microwave irradiation and muffle furnace were 98.29%, 4.32% and 85.36%, 2.48%, respectively.

Lithium leaching via calcium chloride roasting from simulated pyrometallurgical slag of spent lithium ion battery

In the present case, insoluble lithium in the simulated slag which is obtained by pyrometallurgical processing of spent lithium ion batteries (LiBs) is leached aqueously through transformation of insoluble lithium into soluble lithium via roasting with calcium chloride (CaCl2). The change of both Gibbs free energy and the logarithm of the equilibrium constant, which are taken as functions of temperature for the chlorination reaction of simulated slag with CaCl2, are predicted through the simulation with an enthalpy, entropy and heat capacity (HSC) programme. The simulation indicates that CaCl2 is a favourable and effective chlorine donor in this chlorination reaction to yield lithium chloride (LiCl) when the temperature is not less than 500 °C. These predicted results are tested and confirmed experimentally. A maximum of 90.58% lithium recovery can be yielded with the optimal roasting conditions of a temperature of 800 °C for 60 min and a molar ratio of Cl/Li of 1.8:1, along with subsequent leaching conditions of 60 °C for 30 min with a water/calcines mass ratio of 30:1. X-ray diffraction (XRD) results suggest that most of LiAl(SiO3)2 in the slag disappears under the best reaction conditions and is transformed into LiCl.

Determination of Optimal Roasting Conditions for the Production of Gabou

Gabou is a traditional onion-based spice commonly used in Niger. It is prepared in a handcrafted way by roasting of dried onion. This study was conducted to determine the optimal roasting conditions. The traditional processes of Gabou manufacturing were identified through a survey and studied. Gabou were produced at different roasting temperatures and times in presence of the oil quantities in the laboratory. Then sensory analyses were conducted to select the Gabou of best sensory characteristics. The chemical composition of the selected Gabou and their raw materials was determined. The result of the investigation showed that flower stems, green leaves and onion bulbs were used in the production of Gabou. The optimal roasting conditions were obtained at 120&amp;deg;C for 8 min for bulbs Gabou, 120&amp;deg;C for 5 min for green leaves Gabou and 130&amp;deg;C for 11 min for flower stems Gabou in the presence of 1 ml, 2 ml and 0 ml palm oil per 30 g, respectively. Roasting conditions that led to the production of Gabou of good sensory characteristics did not have a significant negative influence (p&amp;lt;0.05) on proximate and mineral composition. On the contrary, they have significantly reduced the moisture content which contributes to the reduction of Gabou shelf life.

Innovative utilization of refractory iron ore via suspension magnetization roasting: A pilot-scale study

In this study, an innovative suspension magnetization roasting (SMR) technology was developed and utilized for the recovery of iron from a typical refractory iron ore. The effects of the roasting temperature, CO reducing gas flow rate, N2 fluidizing gas flow rate, and feeding rate on the iron recovery were investigated. Under the optimal roasting conditions, a continuous and stable pilot scale SMR test was conducted for 72 h, and a staged grinding and staged low-intensity magnetic separation (LIMS) process was designed to upgrade the roasted product. The results showed that with the appropriate SMR conditions — a roasting temperature of 520 °C, CO flow rate of 4.0 m3/h, N2 flow rate of 2.0 m3/h, and feeding rate of 100 kg/h — an iron concentrate with a total iron grade (TFe) of 60.18% and iron recovery of 90.17% could be obtained. Compared to the traditional process of shaft furnace magnetization roasting (SFMR) followed by LIMS, the novel technique developed here could improve the TFe and iron recovery of the iron concentrate by 12–14% and 17–22%, respectively, with well-functioning equipment. During the SMR process, hematite and siderite were transformed into magnetite, which enhanced the magnetism of the iron minerals. The utilization of the SMR method has the potential to provide a significant technological advance in the field of refractory iron ore recovery in China and globally.

Experimental and Kinetic Study of Magnesium Extraction and Leaching from Laterite Nickel Ore by Roasting with Ammonium Sulfate

Laterite-nickel ore was roasted with ammonium sulfate to extract magnesium by a single-factor experiment, and an orthogonal test was employed to optimize the conditions. The optimum roasting conditions were: calcination temperature, 450°C; calcination time, 120 min; molar ratio of reactants, 2 : 1; granularity <80 µm. The kinetics of the roasting process were also studied. The experimental results showed that the extraction rate of magnesium increased as the calcination temperature increased. The reaction rate of magnesium is in accordance with the shrinking non-reacted nuclear model for the solid product formation reaction. The roasting reaction is controlled by internal diffusion. The apparent activation energy is E = 18.96 kJ mol–1. The kinetic equation is $${\text{1}} + {\text{2}}\left( {{\text{1}} - {\alpha\text{}}} \right) - {\text{3}}{{\left( {{\text{1}} - {\alpha\text{}}} \right)}^{{{{\text{2}} \mathord{\left/ {\vphantom {{\text{2}} {\text{3}}}} \right. \kern-0em} {\text{3}}}}}} = {\text{0}}{\text{.05061exp}}\left[ { - {{{\text{18}}{\text{963}}} \mathord{\left/ {\vphantom {{{\text{18}}{\text{963}}} {\left( {RT} \right)}}} \right. \kern-0em} {\left( {RT} \right)}}} \right]t.$$ A single factor experiment and orthogonal test were carried out to optimize the magnesium leaching process reaction conditions. The optimum conditions of the leaching process were: leaching temperature, 60°C; leaching time, 60 min; liquid to solid ratio, 2.5 : 1; stirring intensity, 400 r min–1. The kinetic equation is 1 – (1 – α)2/3 = 0.3991exp(–8632/RT)t. The apparent activation energy is E = 8.63 kJ mol–1. The reaction rate of the leaching process was controlled by external diffusion.

Optimization of Microwave-Assisted Oxidation Roasting of Oxide–Sulphide Zinc Ore with Addition of Manganese Dioxide Using Response Surface Methodology

Abstract The present study deals with a microwave-assisted oxidation roasting oxide–sulphide zinc ore technology of with addition of manganese dioxide. Effects of roasting parameters such as MnO2 addition level, roasting temperature, and holding time are studied by using the Central Composite Design (CCD). Meanwhile, zinc calcines are characterized by phase compositions analyses(XRD), structure characteristics of minerals (FT-IR), micro-area chemical analyses (SEM-EDAX) and elemental valence bonding analyses (XPS), which prove to be in accordance with the CCD results. The optimum roasting conditions are decided as MnO2 addition level being 85.14 %, roasting temperature 680 °C, and holding time 41 mins, and oxidation degree of zinc can reach 88.22 %. Besides, when MnO2 addition level reaches a certain value, zinc will aggregate in a form of ZnMn2O4, one battery material.

Study on the reduction roasting of spent LiNixCoyMnzO2 lithium-ion battery cathode materials

Simple and environment-friendly recovery of valuable metals from spent LIBs was explored. The experimental method, which included reduction roasting and hydrometallurgical recovery, is called a quasi-reversible process. The principle behind the quasi-reversible model could be used to assess the energy consumed during the recovery of metals from cathode active materials. The roasting process was analysed using TG–DSC and Kissinger equation. XRD patterns and mass loss ratios were used to investigate the layered LiNixCoyMnzO2 that broke into Li2CO3, MnO, NiO, Ni and Co. Roasting temperature, coke dosage and roasting time were assessed to determine the leaching efficiency of Li, Ni, Co and Mn. Results indicated that the optimum roasting conditions were roasting temperature of 650 °C, coke dosage of 10% and roasting time of 30 min. The roasted products under the optimum parameters were used to leach the valuable metals, and the leaching efficiencies of Li, Ni, Co and Mn were 93.67%, 93.33%, 98.08% and 98.68%, respectively. Li2CO3 solution recovered from water leaching could be utilised to produce Li2CO3 by evaporative crystallisation. Moreover, divalent solution of Ni, Co and Mn obtained via acid leaching without added reducer could be recycled in the co-precipitation of the ternary precursor.

Green magnetization roasting technology for refractory iron ore using siderite as a reductant

In the present study, a green magnetization roasting process was proposed by using siderite (FeCO3) as the reductant. The influences of the siderite dosage, roasting temperature and roasting time on the magnetization roasting process were investigated. The saturation magnetization of roasted samples was analyzed by a vibrating sample magnetometer (VSM), and the phase transformation was investigated by in situ X-ray diffraction (XRD). The optimal roasting conditions were determined to be a siderite dosage of 40% with a roasting temperature of 700 °C and a roasting time of 10.0 min. The saturation magnetization of the roasted product under optimal conditions was 70.19 A m2 kg−1. The siderite (FeCO3) was transformed to magnetite (Fe3O4) with the intermediate product of wustite (FeO) in the decomposition process. In the meantime, the hematite (Fe2O3) was reduced to magnetite (Fe3O4) by the carbon monoxide released from the decomposition of siderite.

Recoveries of Valuable Metals from Spent Nickel Metal Hydride Vehicle Batteries via Sulfation, Selective Roasting, and Water Leaching

The recoveries of rare earth elements (REEs), nickel, and cobalt from hybrid electric vehicle batteries by sulfation, selective roasting, and water leaching have been studied. The cathode and anode materials of a Panasonic Prismatic Module nickel metal hydride (NiMH) battery were used in the study. The optimal conditions for each step of the process were determined by performing lab-scale experiments. It was found that 8 mol/L of sulfuric acid was sufficient for the sulfation with a solid-to-liquid ratio of 1/5. The optimal roasting conditions was determined to be 850 °C for 2 h. Under optimal conditions, 96% of the REEs could be obtained in the aqueous phase with negligible contamination of Ni and Co. The Ni and Co remained in solid phase as oxides together with traces of aluminum, zinc, and iron oxides. This method provides a way for the separation of the REEs from nickel, cobalt, and other elements present in the NiMH battery, into a leachate suitable for further processing.

A method for recovery of iron, titanium, and vanadium from vanadium-bearing titanomagnetite

An innovative method for recovering valuable elements from vanadium-bearing titanomagnetite is proposed. This method involves two procedures: low-temperature roasting of vanadium-bearing titanomagnetite and water leaching of roasting slag. During the roasting process, the reduction of iron oxides to metallic iron, the sodium oxidation of vanadium oxides to water-soluble sodium vanadate, and the smelting separation of metallic iron and slag were accomplished simultaneously. Optimal roasting conditions for iron/slag separation were achieved with a mixture thickness of 42.5 mm, a roasting temperature of 1200°C, a residence time of 2 h, a molar ratio of C/O of 1.7, and a sodium carbonate addition of 70wt%, as well as with the use of anthracite as a reductant. Under the optimal conditions, 93.67% iron from the raw ore was recovered in the form of iron nugget with 95.44% iron grade. After a water leaching process, 85.61% of the vanadium from the roasting slag was leached, confirming the sodium oxidation of most of the vanadium oxides to water-soluble sodium vanadate during the roasting process. The total recoveries of iron, vanadium, and titanium were 93.67%, 72.68%, and 99.72%, respectively.

Effect of Roasting Method on Physico-Mechanical and Roasting Characteristics of Chickpea (Cicer arietinum)

Chickpea grains were roasted by traditional sand roasting (180, 200 and 220ºC) and microwave roasting (450 W, 600 W and 900 W) for 5, 10 and 15 min. The effects of roasting method and their parameters on physico-mechanical and roasting characteristics were determined. Roasting led to an increase in size, sphericity, angle of repose, porosity and puffing index of chickpea. Significant (p&lt;0.05) reduction in fracture force and coefficient of friction was observed. True density decreased with roasting and the lowest value of 787.87 kg.m-3 was observed on sand roasting at 180°C for 15 min. The highest value of puffing index (179.87 %) and length/width ratio (155.04 %) was observed for sand roasting at 220ºC for 15 min and 5 min, respectively. The force required for rupture of chickpea reduced with roasting, and the lowest value (32.28 N) was observed during sand roasting at 220ºC for 10 min. The optimum roasting condition identified for sand and microwave roasting to obtain higher puffing index, lower hardness and rupture energy was observed to be 220 ºC for 10 min and 600 W for 15 min, respectively.

Effect of microwave irradiation and conventional calcification roasting with calcium hydroxide on the extraction of vanadium and chromium from high‑chromium vanadium slag

A novel high-efficiency method based on microwave irradiation roasting has been proposed to extract valuable metals from minerals. In this study, we employed microwave irradiation and conventional roasting for extracting vanadium and chromium from high‑chromium vanadium slag (HCVS) with the additive calcium hydroxide. Differential thermal-thermogravimetry analysis (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy analysis (SEM-EDS), particle size distribution analysis and chemical analyses were used for the characterization and analysis to explain the mechanism of the roasting process. The results shown that roasting temperature, the m(CaO)/m(V2O5) ratio, and roasting time roasted by microwave irradiation and muffle furnace had significantly effect on extraction ratio of vanadium while the effect on the extraction ratio of chromium was relatively small. For the same roasting temperature, the degree of oxidation of HCVS roasted by microwave irradiation was higher than that roasted by muffle furnace. When the m(CaO)/m(V2O5) ratio is low, Mn4V2O9 and CaV2O6 are formed; with the m(CaO)/m(V2O5) ratio increased, Mn4V2O9 and CaV2O6 gradually converted to CaV2O7, and CaCrO3 is formed. Microwave irradiation decreased the particles size and shortened the roasting time. The optimal roasting conditions was determined to be: roasting temperature of 850°C, m(CaO)/(V2O5) ratio of 0.95, and roasting time of 1.5h. The maximum extraction ratio of vanadium and chromium roasted by microwave irradiation and muffle furnace were 98.29%, 4.32% and 85.36%, 2.48%, respectively.

Investigation into coal-based magnetizing roasting of an iron-rich rare earth ore and the associated mineralogical transformations

The factors influencing goethite to magnetite conversion during magnetizing roasting of an iron-rich rare earth ore using coal as the reductant were explored in the present paper. The effect of temperature, time and reductant addition on magnetite conversion; and the optimal conditions which resulted in complete conversion of goethite to magnetite were determined through the use of satmagan and quantitative X-ray diffraction. For this particular ore, optimal roasting conditions were determined to be a roasting temperature of 600–650°C with the addition of 10–20wt% coal in the mixture and a roasting time of 90min. The mineralogical changes occurring during magnetizing roasting were also investigated using X-ray diffraction. Magnetite formation was found to proceed by the reduction of hematite formed from the dehydroxylation of goethite. X-ray diffraction showed that further reaction of magnetite to form wüstite and fayalite had taken place under highly reducing conditions and temperatures exceeding 650°C. The primary rare earth mineral in this ore, monazite was stable at all roasting conditions whilst florencite underwent thermal decomposition resulting in an increase in the monazite content of the roasted ore.

Kinetics of roasting potash feldspar in presence of sodium carbonate

A novel process was proposed for the utilization of potash feldspar by roasting in the presence of sodium carbonate. The effects of roasting temperature, granularity, molar ratio of sodium carbonate to potash feldspar and roasting time on the silica extraction rate were investigated. Under the optimal roasting conditions, the silica extraction rate was 98%. The optimal conditions, determined using an orthogonal experiment, were found to be roasting temperature of 875 °C, potash feldspar granularity of 74–89 μm, molar ratio of sodium carbonate to potash feldspar of 1.2:1, and roasting time of 80 min. The kinetics of potash feldspar roasting in the presence of sodium carbonate was described by the shrinking core model and the reaction rate was found to be controlled by the chemical reaction at the particle surface. According to the Arrhenius expression, the activation energy was 164.99 kJ/mol, and the process could be expressed as [1-(1-α)1/3]=2.66×105 exp[-164990/(RT)] t.