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International Journal of Minerals,Metallurgy and Materials 2023年第5期30卷 857-867页

作者： Quankuang Zhang Baozhong Ma Chengyan Wang Yongqiang Chen Wenjuan Zhang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

Currently,the process of extracting rubidium from ores has attracted a great deal of attention due to the increasing application of rubidium in high-technology field.A novel process for the comprehensive utilization of rubidium ore resources is proposed in this paper.The process consists mainly of mineral dissociation,selective leaching,and desilication.The results showed that the stable silicon–oxygen tetrahedral structure of the rubidium ore was completely disrupted by thermal activation and the mineral was completely dissociated,which was conducive to subsequent selective leaching.Under the optimal conditions,extractions of 98.67% Rb and 96.23%K were obtained by leaching the rubidium ore.Moreover,the addition of a certain amount of activated Al(OH)_(3) during leaching can effectively inhibit the leaching of silicon.In the meantime,the leach residue was sodalite,which was successfully synthesized to zeolite A by hydrothermal conversion.The proposed process provided a feasible strategy for the green extraction of rubidium and the sustainable utilization of various resources.

关键词： rubidium mineral dissociation selective leaching zeolite A desilication

Suspension calcination and alkali leaching of low-grade high-sulfur bauxite:Desulfurization, mineralogical evolution and desilication

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International Journal of Minerals,Metallurgy and Materials 2020年第5期27卷 602-610页

作者： Hong-fei Wu Jun-qi Li Chao-yi Chen Fei-long Xia Zhen-shan Xie Department of Metallurgical Engineering College of Materials and MetallurgyGuizhou UniversityGuiyang 550025China Guizhou Province Key Laboratory of Metallurgical Engineering and Process Energy Saving Guiyang 550025China

To enable the utilization of low-grade and high-sulfur bauxite, the suspension calcination was used to remove the sulfur and the activate silica minerals, and the calcinated bauxite was subjected to a desilication process in Na OH solution under atmospheric pressure. The desulfurization and desilication properties and mineralogical evolution were studied by X-ray diffraction, thermogravimetry–differential thermal analysis, scanning electron microscopy, and FactSage methods. The results demonstrate that the suspension calcination method is efficient for sulfur removal: 84.21% of S was removed after calcination at 1000°C for 2 min. During the calcination process, diaspore and pyrite were transferred to α-Al2O3, magnetite, and hematite. The phase transformation of pyrite follows the order FeS2 → Fe3O4 → Fe2O3, and the iron oxides and silica were converted into iron silicate. In the alkali-soluble desilication process, the optimum condition was an alkali solution concentration of 110 g/L, a reaction time of 20 min, and a reaction temperature of 95°C. The corresponding desilication ratio and alumina loss ratio were 44.9% and 2.4%, respectively, and the alumina-to-silica mass ratio of the concentrate was 7.9. The Al2O3·2SiO2, SiO2, and Al2O3 formed during the calcination process could react with Na OH solution, and their activity decreased in the order of Al2O3·2 SiO2, SiO2, and Al2O3.

关键词： low-grade bauxite sulfur suspension calcination alkali-soluble desilication Bayer process

Utilization of DTAB as a collector for the reverse flotation separation of quartz from fluorapatite

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International Journal of Minerals,Metallurgy and Materials 2022年第3期29卷 446-454页

作者： Wenbiao Liu Wenxuan Huang Feng Rao Zhanglei Zhu Yongming Zheng Shuming Wen Faculty of Land and Resource Engineering Kunming University of Science and TechnologyKunming 650093China School of Zijin Mining Fuzhou UniversityFuzhou 350108China State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Kunming University of Science and TechnologyKunming 650093China R&D center Yunnan Yuntianhua Co.Ltd.Kunming 650228China College of Chemistry and Chemical Engineering Xi’an University of Science and TechnologyXi’an 710054China

Reverse flotation desilication is an indispensable step for obtaining high-grade fluorapatite. In this work, dodecyltrimethylammoni- um bromide (DTAB) is recommended as an efficient collector for the reverse flotation separation of quartz from fluorapatite. Its collectivity for quartz and selectivity for fluorapatite were also compared with figures corresponding to the conventional collector dodecylamine hydrochlor- ide (DAC) via microflotation experiments. The adsorption behaviors of DTAB and DAC on minerals were systematically investigated with surface chemical analyses, such as contact angle determination, zeta potential detection, and adsorption density measurement. The results re- vealed that compared to DAC, DTAB displayed a similar and strong collectivity for quartz, and it showed a better selectivity (or worse col- lectivity) for fluorapatite, resulting in a high-efficiency separation of the two minerals. The surface chemical analysis results showed that the adsorption ability of DTAB on the quartz surface was as strong as that of DAC, whereas the adsorption amount of DTAB on the fluorapatite surface was much lower than that of DAC, which is associated with the flotation performance. During the floatation separation of the actual ore, 8wt% fluorapatite with a higher grade can be obtained using DTAB in contrast to DAC. Therefore, DTAB is a promising collector for the high-efficiency purification and sustainable utilization of valuable fluorapatite recourses.

关键词： fluorapatite desilication dodecyltrimethylammonium bromide adsorption

Bimetallic PtSn nanoparticles confined in hierarchical ZSM-5 for propane dehydrogenation

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Chinese Journal of Chemical Engineering 2022年第1期35卷 384-391页

作者： Tianlei Wang Zhikang Xu Yuanyuan Yue Tinghai Wang Minggui Lin Haibo Zhu National Engineering Research Center of Chemical Fertilizer Catalyst School of Chemical EngineeringFuzhou UniversityFuzhou 350002China Qingyuan Innovation Laboratory Quanzhou 362801China State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China

A series of PtSn/hierarchical ZSM-5 catalysts were developed for propane dehydrogenation,in which the PtSn bimetallic particles are confined in the mesopores of hierarchical ZSM-5 zeolite.The synthesis of PtSn/hierarchical ZSM-5 catalysts was achieved via the loading of Pt and Sn species onto the hierarchical ZSM-5 catalysts that are obtained through a desilication of conventional ZSM-5.The PtSn/hierarchical ZSM-5 catalysts were fully characterized by XRD,N_(2) adsorption,STEM,XPS,and CO-IR techniques,which reveals that highly dispersed PtSn bimetallic nanoparticles are enclosed into mesopores of hierarchical ZSM-5.The catalytic performance of PtSn/hierarchical ZSM-5 is greatly affected by the concentrations of alkali solution in the desilication process and Sn/Pt ratios in PtSn bimetallic particles.The PtSn1.00/ZSM-5(0.8)catalyst shows the highest efficiency in propane dehydrogenation,which gives an initial conversion of 46%and selectivity of 98%at 570℃.The high efficiency in these PtSn/hierarchical ZSM-5 catalysts for propane dehydrogenation is mainly ascribed to the confinement of PtSn particles in the mesopores of hierarchical ZSM-5 zeolite.

关键词： Hierarchical ZSM-5 Propane dehydrogenation desilication PtSn particles

Distribution behavior of collector in the desilication system of bauxite flotation

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Journal of Central South University of Technology 2001年第2期8卷 125-129页

作者： JIANG Yu ren,XUE Yu lan,CAO Xue feng,XIA Zhong (Department of Mineral Engineering,Central South University, Changsha 410083,China) Department of Mineral Engineering Central South University Changsha China

The distribution behavior of the HZB collector (a kind of long chain fatty acid) in the desilication system of bauxite flotation was studied. The results show that the collector tends towards froth products in the steps of the roughing, the first cleaning and the second cleaning, while towards the tailing product in the step of the scavenging, and in each job except scavenging the collector is mainly on the surface of solids. As for the froth product in the step of the scavenging, it is mainly in solution. To the tailing products of every step, it is mainly in the respective solutions. The collector added to the flotation system is mainly taken out by the last concentrate, by which the taken one occupies 65.2% of the whole, among which, 57.8% is by solid and 7.4% by solution, respectively. And the one by the last tail occupies 34.8% of the whole, among which, 8.8% is by solid and 26.0% by solution, respectively. The sum of the collector in the solution of the last concentrate and tailing is 33.4% of the amount of addition collector, and recycling the solutions will be in favor of decreasing the dosage of collector.

关键词： distribution of collector desilication flotation of bauxite

Pre-desilication and digestion of gibbsitic bauxite with lime in sodium aluminate liquor

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International Journal of Minerals,Metallurgy and Materials 2012年第11期19卷 973-977页

作者： Xiao-lin Pan Hai-yan Yu Kai-wei Dong Gan-feng Tu Shi-wen Bi School of Materials and Metallurgy Northeastern UniversityShenyang 110004China

The effect of lime on the pre-desilication and digestion of gibbsitic bauxite in synthetic sodium aluminate liquor at different tem- peratures was investigated. The bauxite is comprised of gibbsite, aluminogoethite, hematite, kaolin, quartz, and minor boehmite. Lime in- creases the desilication efficiency of the bauxite during the pre-desilication process by promoting the conversion of sodalite and cancrinite to hydrogamet. desilication reactions during the digestion process promoted by lime result in the loss of A1203 entering the red mud, but the amount of aluminogoethite-to-hematite conversion promoted by lime leads to the increase of aluminogoethific A1203 entering the digested liquor. The alumina digestion rate at 245~C is higher than that at 145 C due to the more pronounced conversion of aluminogoethite to hema- tite. The soda consumption during the digestion process decreases due to lime addition, especially at higher temperatures.

关键词： bauxite ore treatment lime sodium aluminate desilication alumina Bayer process

Hierarchical ZSM-5 zeolite with radial mesopores:Preparation,formation mechanism and application for benzene alkylation

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Frontiers of Chemical Science and Engineering 2020年第2期14卷 248-257页

作者： Darui Wang Hongmin Sun Wei Liu Zhenhao Shen Weimin Yang State Key Laboratory of Green Chemical Engineering and Industrial Catalysis Shanghai Research Institute of Petrochemical TechnologySinopecShanghai 201208China

Hierarchical ZSM-5 zeolite with radial mesopores is controllably synthesized using piperidine in a NaOH solution.The piperidine molecules enter the zeolite micropores and protect the zeolite framework from extensive desilication.The areas containing fewer aluminum atoms contain fewer piperidine protectant molecules and so they dissolve first.Small amounts of mesopores are then gradually generated in areas with more aluminum atoms and more piperidine protectant.In this manner,radial mesopores are formed in the ZSM-5 zeolite with a maximal preservation of the micropores and active sites.The optimal hierarchical ZSM-5 zeolite,prepared with a molar ratio of piperidine to zeolite of 0.03,had a mesopore surface area of 136 m·g and a solid yield of 80%.The incorporation of the radial mesopores results in micropores that are interconnected which shortened the average diffusion path length.Compared to the parent zeolite,the hierarchical ZSM-5 zeolite possesses more accessible acid sites and has a higher catalytic activity and a longer lifetime for the alkylation of benzene.

关键词： hierarchical ZSM-5 zeolite protective desilication piperidine radial mesopores benzene alkylation

Alkali desilicated coal fly ash as substitute of bauxite in lime-soda sintering process for aluminum production

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Transactions of Nonferrous Metals Society of China 2010年第S1期20卷 169-175页

作者：白光辉滕玮王香港秦晋国徐鹏 Department of Chemistry Xi'an University of Architecture and Technology Department of Chemistry Fudan University Pingshuo Coal Industry Company

By desilication treatment,the Al2O3/SiO2 molar ratio of coal fly ash could be improved to the range of 1.63-2.0.The desilicated coal fly ash(DSCFA)was enriched in alumina extraction.A processing technology was developed for alumina extraction from the DSCFA with the lime sintering process.Ca/(SiO2+TiO2)molar ratio,and NaO/Al2O3 molar ratio,sintering time,and temperature were the most significant parameters impacting on the aluminum extraction efficiency.The optima aluminum extraction efficiency was obtained under conditions of Ca/(SiO2+TiO2)molar ratio of 2.0,NaO/Al2O3 molar ratio of 0.98,and sintering at 1 200 ℃for 60 min.Astandard industrial dissolution method was used under conditions of caustic ratio(αk=n(NaO)/n(Al2O3)of 2.0,Al2O3 concentration of 50 g/L,sodium hydroxide concentration(Nk)of 60.78 g/L,Na2CO3 concentration of 10 g/L,temperature of 85℃, and dissolution duration of 10 min.The final aluminum extraction efficiency was 90%.

关键词： coal fly ash alumina desilication lime-soda sintering dissolution

Using ultrasound to improve the sequential post-synthesis modification method for making mesoporous Y zeolites

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Frontiers of Chemical Science and Engineering 2020年第2期14卷 275-287页

作者： Rongxin Zhang Peinan Zhong Hamidreza Arandivan Yanan Guan Jinmin Liu Na Wang Yilai Jiao Xiaolei Fan Department of Chemical Engineering and Analytical Science School of EngineeringThe University of ManchesterManchesterM139PLUK Laboratory of Advanced Catalysis for Sustainability School of ChemistryThe University of SydneySydney 2006Australia Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Sino-Spanish Advanced Materials Institute Shenyang University of Chemical TechnologyShenyang 110142China Advanced Manufacturing Institute of Polymer Industry(AMIPI) Shenyang University of Chemical TechnologyShenyang 110142China Key Laboratory of Materials and Advanced Equipment for Resource Chemical Technology(Ministry of Education) Shenyang University of Chemical TechnologyShenyang 110142China

Mesoporous Y zeolites were prepared by the sequential chemical dealumination(using chelating agents such as ethylenediaminetetraacetic acid,H EDTA,and citric acid aqueous solutions)and alkaline desilication(using sodium hydroxide,NaOH,aqueous solutions)treatments.Specifically,the ultrasound-assisted alkaline treatment(i.e.,ultrasonic treatment)was proposed as the alternative to conventional alkaline treatments which are performed under hydrothermal conditions.In comparison with the hydrothermal alkaline treatment,the ultrasonic treatment showed the comparatively enhanced efficiency(with the reduced treatment time,i.e.,5 min vs.30 min,all with 0.2 mol·L NaOH at 65°C)in treating the dealuminated Y zeolites for creating mesoporosity.For example,after the treatment of a dealuminated zeolite Y(using 0.1 mol·L H EDTA at 100°C for 6 h),the ultrasonic treatment produced the mesoporous zeolite Y with the specific external surface area()of 160 m·g and mesopore volume()of 0.22 cm·g,being slightly higher than that by the conventional method(i.e.,=128 m·g and=0.19 cm·g).The acidic property and catalytic activity(in catalytic cracking of-octane)of mesoporous Y zeolites obtained by the two methods were comparable.The ultrasonic desilication treatment was found to be generic,also being effective to treat the dealuminated Y zeolites by citric acid.Additionally,the first step of chemical dealumination treatment was crucial to enable the effective creation of mesopores in the parent Y zeolite(with a silicon-to-aluminium ratio,Si/Al=2.6)regardless of the subsequent alkaline desilication treatment(i.e.,ultrasonic or hydrothermal).Therefore,appropriate selection of the condition of the chemical dealumination treatment based on the property of parent zeolites,such as Si/Al ratio and crystallinity,is important for making mesoporous zeolites effectively.

关键词： zeolite Y mesoporous zeolite post-synthesis treatment ultrasound chemical dealumination treatment alkaline desilication treatment

Effects of acidity and mesoporosity development in ZSM-5 on biomass-derived ethylene oligomerization for liquid fuel synthesis

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Journal of Chongqing University 2015年第2期14卷 39-53页

作者：汪宝林 Research Institute of Sinopec Sichuan Vinylon Works

The acidities of different Si O2/Al2O3 ratio ZSM-5 zeolites, CBV3024 E, CBV5524 G and CBV8014 were investigated with temperature-programmed desorption of ammonia and diffuse reflectance infrared Fourier transform spectroscopy, and their catalytic performances were evaluated to screen the optimal CBV8014 catalyst for ethylene oligomerization. The mesoporosity development in CBV8014 zeolite was conducted by desilication in alkaline medium. The porous characteristics, structural properties and acidic properties of parent and alkali-treated CBV8014 zeolites were studied, and their catalytic performances were evaluated, indicating that CBV8014 treated by 0.2 mol/L NaO H solution has an appropriate mesoporosity development, well preservation of catalyst acidity and crystallinity, good catalytic activity and stability, and high liquid fuel yield for ethylene oligomerization. The effect of reaction pressure on ethylene oligomerization over 0.2HZ catalyst was also investigated, and JP-8 likely hydrocarbon jet fuel was obtained by using 0.2HZ catalyst at 0.344 75 MPa with a high catalyst stability and high liquid yield.

关键词： ZSM-5 acidity desilication mesoporosity development ethylene oligomerization