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Journal of Rare Earths 2024年第2期42卷 409-414,I0006页

作者： Yanyan Zhao Xu Sun Deliang Meng Xiangsheng Liu Qiang Zhong Zongyu Feng National Engineering Research Center for Rare Earth Grirem Advanced Materials Co.Ltd.Beijing0088China Rare Earth Functional Materials(Xiong'an)Innovation Center Co. Ltd.Xiongan071700China General Research Institute for Nonferrous Metals Beijing100088China

To find a greener and more economical approach for treating the Mountain Pass rare earth concentrate(MPREC),a novel "Combination Method",including the processes of oxidizing roasting,HCI leaching and sulfuric acid roasting,is proposed in this research.In this paper,the effect of phase transition behavior in hydrochloric acid leaching during oxidative roasting at 450-600℃ was studied.During roasting,the bastnasite in MPREC is decomposed into CeLa_(2)O_(3)F_(3) and(Ce_(0.33),La_(0.33),Ca_(0.33))O_(1.5).As the CeLa_(2)O_(3)F_(3) phase has the fluorine-fixation effect,the generated CeLa_(2)O_(3)F_(3) phase can not be dissolved by HCI after roasting at 500 and 550℃,but it can be decomposed by HCI after roasting at over 600℃,resulting in the improvement of the leaching rate of total F element.The maximum leaching efficiency of rare earth elements(REEs) can reach 70.32 wt% at the roasting temperature of 550℃.After roasting at over 600℃,some F^-ions in the solution combined with RE^(3+) to form REF_(3) precipitate and enter the leaching residue,and the others are in the form of [CeF_(3)]^+ in the leaching solution during leaching,therefore,the leaching efficiency of non-ce rium REEs decreases while that of cerium element increases.This work provides basic research for optimizing the actual production process of MPREC.

关键词： Mountain pass rare earth mine roasting Phase change Rare earths

Effect of high temperature short time infrared roasting of peanuts

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Journal of Future Foods 2024年第2期4卷 173-178页

作者： Rahi Golani Chinglen Leishangthem Hongwei Xiao Qi Zhang P.P.Sutar Department of Food Process Engineering National Institute of Technology RourkelaOdisha 769008India College of Engineering China Agricultural UniversityBeijing 100083China College of Mechanical Engineering Yangzhou UniversityYangzhou 225127China

roasting is the most common processing method that enhances color,and texture.In this study,infrared roasting of peanuts was done using an infrared rotary dryer.roasting was operated at 90%infrared power(630 W)with different rotating speed(1 and 2 r/min).The effect of roasting was studied at different moisture levels(7.66%,11.49%,and 13.72%db).From the study,the color parameter,L*value,was found to be significantly different(Proasting time,and the values decreased from 84.34%to 71.74%.Minimal changes in total phenolic content were found and varied from 3.62 to 2.10 mg/g GAE,an appropriate limit for good-quality roasted peanuts.The hardness of roasted peanuts ranged from 12.25 to 39.43 N.Moisture content 13.72%,and 1 r/min is the best possible treatment for infrared peanut roasting,significantly enhancing the quality of peanuts.This study concluded that high-power short-time infrared roasting could give good-quality roasted peanuts with optimum bioactive compounds.

关键词： roasting Infrared Total phenolic content Antioxidant activity

Separation of Sc_(2)O_(3) from Bayan Obo tailings through an innovative roasting method

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Rare Metals 2022年第3期41卷 1071-1076页

作者： Xin-Jun Bao Zhi-Jian Wang Liu-Jiang Xi Ji-Bo Liu Zheng-Fu Su Tao Yang Wei Cheng De-Bi Zhou Institute for Energy-Storing Materials Research Hunan Rare Earth Metal Material Research InstituteChangsha 410126China College of Chemistry and Chemical Engineering Central South UniversityChangsha 410083China School of Metallurgical Engineering Hunan University of TechnologyZhuzhou 412007China

Sc_(2)O_(3)was successfully extracted and separated from Bayan Obo tailings by a CaCl_(2)-reductive carbon powder-combinative roasting method.The optimum pro-cess condition was obtained through adjusting specific ef-fect factors.It is found that Sc_(2)O_(3)with the ratio of 87.51%is leached out under roasting temperature of 800℃for 2 h through adding 73%CaCl_(2),and 20%reductive carbon powder with liquid to solid ratio of 3.Moreover,the specific reaction mechanism during roasting process was investi-gated by thermogravimetric–differential scanning calorimetry(TG-DSC)and X-ray diffraction(XRD)tech-niques.The results show that the main phases(SiO_(2),CaF_(2) and NaFeSi_(2)O_(6))as well as important phases(LiScSi_(2)O_(6),REFCO_(3)and REPO_(4))would turn into new phases(CaFe-SiO_(4),Fe,Ca_(3)(PO_(4))_(2),NaCl,RE_(2)O_(3)and Sc_(2)O_(3))after com-plicated reactions,which effectively break up the original mineral compositions and activate the existing state of containing scandium matter,consequently facilitating the subsequent hydrochloric acid leaching process.

关键词： Bayan Obo tailings roasting Decomposition Sc_(2)O_(3)

Two-stage cyclic ammonium sulfate roasting and leaching of extracting vanadium and titanium from vanadium slag

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Chinese Journal of Chemical Engineering 2022年第7期35卷 39-47页

作者： Qing Lin Guoquan Zhang Kun Wang Dongmei Luo Siyang Tang Hairong Yue School of Chemical Engineering Sichuan UniversityChengdu 610065China

Compared with traditional sodium or calcification roasting process for vanadium extraction from raw vanadium slag(V-slag),ammonium sulfate(AS)roasting could reduce about 470℃ roasting temperature and avoid Cl_(2),HCl,sodium-containing waste-water and waste gypsum discharging.To reduce the amount of AS added in vanadium extraction process,an efficient AS two-stage cyclic roasting and acid leaching process was proposed.The result of TG analysis indicates V-slag could be decomposed in 275-380℃ using AS roasting process.Using 2.03:1 total mass ratio of AS to V-slag,90.86%V and 80.54%Ti could be extracted after 380℃ roasting for 30 min and 8%initial concentration of H_(2)SO_(4) leaching at 70℃ for 100 min.XRD analysis indicates V-containing spinel phase in the 1st stage leaching residue would be efficiently decomposed by the cyclic two-stage roasting and leaching process.Furthermore,the valence of V(Ⅲ)in raw V-slag was not changed after the 1st AS roasting stage,but a part of V(Ⅲ)in the 1st leaching residue was oxidized to V(V)after 2nd roasting process.

关键词： Vanadium Titanium roasting Leaching

Recovery of vanadium from vanadium slag by composite additive roasting-acid leaching process

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Journal of Iron and Steel Research(International) 2023年第7期30卷 1426-1439页

作者： Jun-yi Xiang Ming-shuai Luo Xi Lu Lu-wei Bai Zhong-peng Zhu Qing-yun Huang Sheng-qin Zhang Kun-peng Guo Xue-wei Lv College of Metallurgy and Materials Engineering Chongqing University of Science and TechnologyChongqing 401331China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

To minimize the vanadium content in the vanadium extraction tailings, composite additive roasting with (CaO + MgO) and subsequent acid leaching process was carried out dealing with vanadium-bearing converter slag. The effect of additive with different MgO/(CaO + MgO) molar ratios on the roasting and leaching behaviours of vanadium slag was investigated, and the optimum process conditions were obtained. The results show that in the roasting experiment, under the conditions of roasting temperature of 850 ℃ and roasting time of 2 h, the main kinds of vanadate transformed from Ca_(2)V_(2)O_(7) to Ca_(5)Mg_(4)V_(6)O_(2)4 and then to Mg_(2)V_(2)O_(7) with the increase in the MgO/(CaO + MgO) molar ratio. In the leaching experiment, under the conditions of particle size less than 75 μm, leaching temperature of 50 ℃, pH of 2.5, liquid–solid ratio of 20:1, and MgO/(CaO + MgO) molar ratio of 1:3, the leaching efficiency of vanadium is increased by about 5%, but the substitution of MgO for most or all of CaO will significantly reduce the leaching efficiency of vanadium. Furthermore, the leaching efficiency of impurities (P and Cr) can also be decreased by a composite addictive (CaO + MgO) roasting process. The X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry, and X-ray photoelectron spectroscopy of the original vanadium slag and solid products of both roasting and leaching processes were also evaluated.

关键词： Vanadium slag roasting Leaching Vanadate Recovery

Rare earth recovery from fluoride molten-salt electrolytic slag by sodium carbonate roasting-hydrochloric acid leaching

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Journal of Rare Earths 2023年第8期41卷 1242-1249,I0005页

作者： Hao Wu Huashan Yan Yanzhen Liang Sen Qiu Xiaowen Zhou Dongmei Zhu Tingsheng Qiu Collaborative Innovation Center for Development and Utilization of Rare Metal Resources Co-sponsored by Ministry of Education and Jiangxi Province Jiangxi University of Science and TechnologyGanzhou 341000China Jiangxi Province Key Laboratory of Mining Engineering Jiangxi University of Science and TechnologyGanzhou 341000China School of Resources and Environmental Engineering Jiangxi University of Science and TechnologyGanzhou 341000China

Fluorinated rare earth molten-salt electrolytic slag contains a considerable amount of rare earth elements,as well as a variety of heavy metals and fluorides that cause environmental pollution.Therefore,it is of great importance to fully utilise this resource.In this study,the transformation mechanism of fluorinated rare earth molten-salt electrolytic slag roasted with sodium carbonate,and the regulation mechanism of rare earth leaching under different roasting conditions were investigated with the help of thermodynamic calculation of the reactions and kinetic analysis.The thermodynamic and differential thermal thermogravimetric(DTA-TG)analysis shows that the transformation of rare earth fluoride to rare earth oxide is promoted at elevated temperature.Furthermore,the leaching experimental results show that increasing the temperature,time,hydrochloric acid concentration,and liquid-solid ratio can effectively promote the recovery of rare earths.The optimum experimental conditions are a roasting temperature of 700℃,roasting time of 2 h,and sodium carbonate to molten salt electrolytic slag mass ratio of 0.6,followed by leaching at 80℃with a liquid-solid ratio of 10:1 by adding 3 moI/L hydrochlo ric acid with stirring for 2 h.Under these conditions,the rare earths in the molten salt electrolytic slag are biologically transformed at a lower temperature and the leaching efficiency of rare earths exceeds 98%.

关键词： Fluorinated rare earth molten-salt electrolytic slag Sodium carbonate roasting Transformation mechanism Leaching Rare earths

Defluorination of bastnaesite by steam roasting process

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Journal of Rare Earths 2022年第12期40卷 1963-1968,I0006页

作者： Shuchen Sun Ying Yang Ganfeng Tu Faxin Xiao School of Metallurgy Northeastern UniversityShenyang 110819China College of Chemical Engineering Shenyang University of Chemical TechnologyShenyang 110142China

The bastnaesite was defluorinated by steam roasting process,and fluorine was removed in the form of hydrogen fluoride to realize the separation from rare earth.The effects of particle size of raw material,roasting temperature and time on defluorination rate of bastnaesite were studied.The suitable conditions of steam roasting process are that the particle size of raw material is less than 74μm,the roasting temperature is 1000℃and the roasting time is 4 h.The defluorination rate of bastnaesite is close to 100%under above these conditions.When the temperature rises to 1000℃,the voids on the surface of the particles increase obviously,and there is a developed network of voids,which indicates that the fluorine oxides in bastnaesite react fully with the saturated water vapor at this stage,and a large amount of fluorine escapes in the form of hydrogen fluoride from the surface and inside of the mineral.X-ray diffraction results show that there are only rare-earth oxides in the form of Ce_(0.33)La_(0.33)Ca_(0.33)O_(1.5)and Ce_(7)O_(12)in the slag.The results of energy spectra and chemical analysis show that the fluorine in the baking sand was basically completely removed.

关键词： Bastnaesite roasting Steam decomposition Defluorination reaction Defluorination rate Rare earths

Interactive effect of hot air roasting processes on the sensory property,allergenicity,and oil extraction of sesame(Sesamum indicum L.)seeds

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Grain & Oil Science and Technology 2023年第2期6卷 71-81页

作者： Shudong He Tiange Pan Zuoyong Zhang Yanni Wu Hanju Sun Youshui Ma Yi Zhang School of Food and Biological Engineering Engineering Research Center of Bio-Process of Ministry of EducationKey Laboratory for Agricultural Products Processing of Anhui ProvinceHefei University of TechnologyHefei 230009AnhuiChina Anhui Fengyang Yushan Grease Co. Ltd.Fengyang 233100AnhuiChina Department of Food Science The Pennsylvania State UniversityUniversity ParkPA 16802USA

Sesame seeds are a healthy food ingredient and an oil crop for sesame oil production;however,it has recently been recognized as an essential allergenic food by FAO/WHO.This research investigated the relationship between the hot air roasting process(at 120,150,and 180℃ for 10,20,and 30 min)and several quality attributes of sesame seeds since roasting is the key process for preparing sesame seeds for both consumption and oil production.The hot air process followed the central composite design.The changes of sesame in terms of color,sensory properties(odor,texture,color,and taste),allergenicity caused by oleosins(ses i 4 and ses i 5),as well as oil extraction and quality were monitored using a colorimeter,sensory evaluation panelists,ELISA,as well as oil yield and acid value,respectively.roasting temperature influenced the product quality more than roasting time,although the two processing parameters significantly interacted with each other(Proasting generated attractive flavor,order,appearance,and crispy texture.Allergenicity was high in sesame seeds after high-temperature roasting,according to IgE binding capacity test.Sesame oil extraction was favored by high-temperature roasting,which,however,adversely affected the oil quality.The optimal roasting conditions were 150.5℃ for 15 min for optimized sesame seeds quality in terms of sensory properties and allergenicity,while roasting at 158℃ for 10 min was optimal for sesame oil production.The finding will benefit the sesame seed industry.

关键词： Sesame seeds roasting Sesame oil Allergenicity Sensory evaluation

Comprehensive comparison on the chemical metabolites and taste evaluation of tea after roasting using untargeted and pseudotargeted metabolomics

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Food Science and Human Wellness 2022年第3期11卷 606-617页

作者： Zongde Jiang Zisheng Han Mingchun Wen Chi-Tang Ho You Wu Yijun Wang Na Xu Zhongwen Xie Jinsong Zhang Liang Zhang Xiaochun Wan State Key Laboratory of Tea Plant Biology and Utilization Anhui Agricultural UniversityHefei 230036China International Joint Laboratory on Tea Chemistry and Health Effects of Ministry of Education Anhui Agricultural UniversityHefei 230036China Department of Food Science Rutgers UniversityNew BrunswickNJ 08901USA

roasting is a common manufacture technology for processing various teas.It is not only used in decreasing the water content of finished tea,but also improving the flavor of teas.In the present study,the roasted and non-roasted teas were compared by liquid-chromatography mass spectrometry and sensory evaluation.The roasted tea tasted less bitter and astringent.The content of main galloylated and simple catechins,caffeine and theobromine in roasted were significantly lower than non-roasted teas.Targeted taste-compounds metabolomics revealed that(-)-epigallocatechin gallate,kaempferol-glucose-rhamnose-glucose and(-)-epicatechin gallate were main contributors tightly correlated to astringent intensity.Flavonol glycosides including kaempferol-glucose,quercetin-glucose,kaempferol-glucose-rhamnose-glucose,and quercetin-glucose-rhamnose-glucose in roasted teas were also significantly less than non-roasted teas.To study the chemical changes during roasting,tea with a strong astringency was roasted under 80,100,120,140,and 160°C.With the increase of roasting temperature,the bitter and astringent intensity of tea was gradually decreased,but the main astringent compounds including(-)-epigallocatechin,(-)-epigallocatechin gallate and kaempferol/quercetin glycosides were irregularly varied with temperature.The Pearson correlation coefficient analysis suggested procyanidin B2,coumaroylquinic acids and gallotannins were tightly correlated to the astringent and bitter perceptions,while N-ethyl-2-pyrrolidonesubstituted flavan-3-ols were negatively correlated.

关键词： Taste roasting Metabolomics Correlation coefficient Quinic acid

roasting and leaching behaviors of vanadium and chromium in calcification roasting–acid leaching of high-chromium vanadium slag

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International Journal of Minerals,Metallurgy and Materials 2018年第5期25卷 515-526页

作者： Jing Wen Tao Jiang Mi Zhou Hui-yang Gao Jia-yi Liu Xiang-xin Xue School of Metallurgy Northeastern University Liaoning Key Laboratory for Recycling Science of Metallurgical Resources

Calcification roasting–acid leaching of high-chromium vanadium slag(HCVS)was conducted to elucidate the roasting and leaching behaviors of vanadium and chromium.The effects of the purity of Ca O,molar ratio between Ca O and V_2O_5(n(Ca O)/n(V_2O_5)),roasting temperature,holding time,and the heating rate used in the oxidation–calcification processes were investigated.The roasting process and mechanism were analyzed by X-ray diffraction(XRD),scanning electron microscopy(SEM),and thermogravimetry–differential scanning calorimetry(TG–DSC).The results show that most of vanadium reacted with Ca O to generate calcium vanadates and transferred into the leaching liquid,whereas almost all of the chromium remained in the leaching residue in the form of(Fe_(0.6)Cr_(0.4))_2O_3.Variation trends of the vanadium and chromium leaching ratios were always opposite because of the competitive reactions of oxidation and calcification between vanadium and chromium with Ca O.Moreover,Ca O was more likely to combine with vanadium,as further confirmed by thermodynamic analysis.When the HCVS with Ca O added in an n(Ca O)/n(V_2O_5)ratio of 0.5 was roasted in an air atmosphere at a heating rate of 10°C/min from room temperature to 950°C and maintained at this temperature for 60 min,the leaching ratios of vanadium and chromium reached91.14%and 0.49%,respectively;thus,efficient extraction of vanadium from HCVS was achieved and the leaching residue could be used as a new raw material for the extraction of chromium.Furthermore,the oxidation and calcification reactions of the spinel phases occurred at 592and 630°C for n(Ca O)/n(V_2O_5)ratios of 0.5 and 5,respectively.

关键词： high-chromium vanadium slag calcification roasting roasting behaviors leaching behaviors vanadium extraction