Fenglin Dai, Junhui Guo, Yufeng He, Pengfei Song, Rongmin Wang
Abstract Montmorillonite (Mnt), a clay mineral with a nanolayered structure, was combined with an Fe-based metal–organic framework (MOF; MIL-53(Fe)) using an in situ growth technique that yielded a novel eco-friendly clay-based adsorbent (MIL-53(Fe)@Mnt). The adsorbent was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis and N2 gas adsorption. The MIL-53(Fe) particles grew on the surface of the nanolayered Mnt and the MIL-53(Fe) particle size became smaller. The adsorption performance of MIL-53(Fe)@Mnt was investigated by removing methylene blue (MB), and optimization experiments were carried out to study the effects of contact time, pH, initial dye concentration and adsorbent mass on the adsorption processes. The MIL-53(Fe)@Mnt exhibited excellent adsorption capacity for MB, namely 313.7 mg g−1, which was 3.02 times and 3.54 times greater than that of pure Mnt and MIL-53(Fe), respectively. Adsorption was fitted with the Langmuir isotherm model and followed a pseudo-second order kinetic model. The MIL-53(Fe)@Mnt obtained is a low-cost and eco-friendly adsorbing material and might be a candidate for removing dyes during water treatment.
{"title":"Enhanced thermal stability and adsorption performance of MIL-53(Fe)@montmorillonite","authors":"Fenglin Dai, Junhui Guo, Yufeng He, Pengfei Song, Rongmin Wang","doi":"10.1180/clm.2021.23","DOIUrl":"https://doi.org/10.1180/clm.2021.23","url":null,"abstract":"Abstract Montmorillonite (Mnt), a clay mineral with a nanolayered structure, was combined with an Fe-based metal–organic framework (MOF; MIL-53(Fe)) using an in situ growth technique that yielded a novel eco-friendly clay-based adsorbent (MIL-53(Fe)@Mnt). The adsorbent was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis and N2 gas adsorption. The MIL-53(Fe) particles grew on the surface of the nanolayered Mnt and the MIL-53(Fe) particle size became smaller. The adsorption performance of MIL-53(Fe)@Mnt was investigated by removing methylene blue (MB), and optimization experiments were carried out to study the effects of contact time, pH, initial dye concentration and adsorbent mass on the adsorption processes. The MIL-53(Fe)@Mnt exhibited excellent adsorption capacity for MB, namely 313.7 mg g−1, which was 3.02 times and 3.54 times greater than that of pure Mnt and MIL-53(Fe), respectively. Adsorption was fitted with the Langmuir isotherm model and followed a pseudo-second order kinetic model. The MIL-53(Fe)@Mnt obtained is a low-cost and eco-friendly adsorbing material and might be a candidate for removing dyes during water treatment.","PeriodicalId":10311,"journal":{"name":"Clay Minerals","volume":"56 1","pages":"99 - 107"},"PeriodicalIF":1.5,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45195876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
p. 50, Table 1, footnote b: instead of “..are the two marks of the same sample”, read “are the same sample”; and footnote d: instead of “...are an approximations”, read “are approximations” p. 50, right column, lines 5–6: instead of “Such a phenomenon is ascribed to the habitation where Kln particles distributed in the previous EKln. That is,” read “This difference between the internal and external surfaces is ascribed to the distribution of Kln particles in EKln, i.e.”
{"title":"Kaolinite-armoured polyurea microcapsules fabricated on Pickering emulsion: controllable encapsulation and release performance of a lipophilic compound — ERRATUM","authors":"Cunjun Li, Minghao Wang, Zhaoliang Liu, Yanqi Xu, Chunhui Zhou, Linjiang Wang","doi":"10.1180/clm.2021.21","DOIUrl":"https://doi.org/10.1180/clm.2021.21","url":null,"abstract":"p. 50, Table 1, footnote b: instead of “..are the two marks of the same sample”, read “are the same sample”; and footnote d: instead of “...are an approximations”, read “are approximations” p. 50, right column, lines 5–6: instead of “Such a phenomenon is ascribed to the habitation where Kln particles distributed in the previous EKln. That is,” read “This difference between the internal and external surfaces is ascribed to the distribution of Kln particles in EKln, i.e.”","PeriodicalId":10311,"journal":{"name":"Clay Minerals","volume":"56 1","pages":"168 - 168"},"PeriodicalIF":1.5,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42331542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Küster, S. Kaufhold, Emanetoullah Limam, Omar Jatlaoui, Oumar Ba, Abdellahi Maham Zein Mohamed, M. Pohlmann-Lortz, M. Ranneberg, K. Ufer
Abstract Non-metallic raw materials are largely unexplored in many African countries. In an attempt to reduce this knowledge gap, kaolin occurrences in three promising regions of southern Mauritania were examined. The aim of the paper is to describe the occurrences and characterize the material in terms of mineralogy and potential technical use in the ceramics industry. The kaolins are geologically associated with various sedimentary rock units in either the Coastal Basin (Kaédi), the Mauritanide Belt (Hassi Abyad) or the Taoudeni Basin (Néma). Geochemical data show Al2O3 contents of between 9% and 38% (corresponding to 23–96% kaolinite). Samples from the Hassi Abyad and Kaédi regions have greater kaolinite contents on average and were further investigated mineralogically. The kaolin from the Néma region contained less kaolinite (<50 mass%). The region is also less accessible and hence is not considered further in this study. X-ray diffraction, X-ray fluorescence and infrared spectroscopy confirmed the geochemically calculated kaolinite contents of the kaolins and identified quartz, anatase and goethite as the remaining major mineral constituents. The degree of structural disorder of the kaolinites (determined by infrared spectroscopy) is generally greater in the Kaédi occurrences than at Hassi Abyad. Ceramic tests proved that all of these kaolin raw materials might be used for the production of ceramics, and some may even be used for fine ceramics. From an economic point of view, the Hassi Abyad deposit is interesting in terms of its quality and reserves, aspects that will be addressed in detail in a follow-up study.
{"title":"Investigation of unexplored kaolin occurrences in southern Mauritania and preliminary assessment of possible applications","authors":"D. Küster, S. Kaufhold, Emanetoullah Limam, Omar Jatlaoui, Oumar Ba, Abdellahi Maham Zein Mohamed, M. Pohlmann-Lortz, M. Ranneberg, K. Ufer","doi":"10.1180/clm.2021.26","DOIUrl":"https://doi.org/10.1180/clm.2021.26","url":null,"abstract":"Abstract Non-metallic raw materials are largely unexplored in many African countries. In an attempt to reduce this knowledge gap, kaolin occurrences in three promising regions of southern Mauritania were examined. The aim of the paper is to describe the occurrences and characterize the material in terms of mineralogy and potential technical use in the ceramics industry. The kaolins are geologically associated with various sedimentary rock units in either the Coastal Basin (Kaédi), the Mauritanide Belt (Hassi Abyad) or the Taoudeni Basin (Néma). Geochemical data show Al2O3 contents of between 9% and 38% (corresponding to 23–96% kaolinite). Samples from the Hassi Abyad and Kaédi regions have greater kaolinite contents on average and were further investigated mineralogically. The kaolin from the Néma region contained less kaolinite (<50 mass%). The region is also less accessible and hence is not considered further in this study. X-ray diffraction, X-ray fluorescence and infrared spectroscopy confirmed the geochemically calculated kaolinite contents of the kaolins and identified quartz, anatase and goethite as the remaining major mineral constituents. The degree of structural disorder of the kaolinites (determined by infrared spectroscopy) is generally greater in the Kaédi occurrences than at Hassi Abyad. Ceramic tests proved that all of these kaolin raw materials might be used for the production of ceramics, and some may even be used for fine ceramics. From an economic point of view, the Hassi Abyad deposit is interesting in terms of its quality and reserves, aspects that will be addressed in detail in a follow-up study.","PeriodicalId":10311,"journal":{"name":"Clay Minerals","volume":"56 1","pages":"126 - 139"},"PeriodicalIF":1.5,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45647277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jun Ren, Shuqiong Luo, S. Shi, H. Tan, Xianfeng Wang, Min Liu, Xiang-guo Li
Abstract Polycarboxylate superplasticizer (PCE) is sensitive to the clay present in concrete aggregates. In particular, Montmorillonite (Mnt), an impurity inevitably contained in the aggregate, can significantly influence the performance of concrete. In an effort to improve the compatibility of PCE, a zwitterionic PCE with cationic amide groups and shorter side-chain lengths was synthesized via free radical copolymerization. The optimal synthesis condition was verified via Box-Behnken design. In addition to characterizing the PCE, the performance of PCE in cement pastes with or without Na-Mnt was examined and the underlying mechanism was explored. The results show that, compared with commercially available PCE, the required dosage of PCE for cements containing Na-Mnt decreased. Unlike commercially available PCE, no intercalation occured on the newly manufactured clay-tolerant PCE within the layers of Mnt, resulting in a greater sorption thickness and improved dispersion of the cements containing Na-Mnt.
{"title":"Synthesis and optimization of a montmorillonite-tolerant zwitterionic polycarboxylate superplasticizer via Box-Behnken design","authors":"Jun Ren, Shuqiong Luo, S. Shi, H. Tan, Xianfeng Wang, Min Liu, Xiang-guo Li","doi":"10.1180/clm.2021.25","DOIUrl":"https://doi.org/10.1180/clm.2021.25","url":null,"abstract":"Abstract Polycarboxylate superplasticizer (PCE) is sensitive to the clay present in concrete aggregates. In particular, Montmorillonite (Mnt), an impurity inevitably contained in the aggregate, can significantly influence the performance of concrete. In an effort to improve the compatibility of PCE, a zwitterionic PCE with cationic amide groups and shorter side-chain lengths was synthesized via free radical copolymerization. The optimal synthesis condition was verified via Box-Behnken design. In addition to characterizing the PCE, the performance of PCE in cement pastes with or without Na-Mnt was examined and the underlying mechanism was explored. The results show that, compared with commercially available PCE, the required dosage of PCE for cements containing Na-Mnt decreased. Unlike commercially available PCE, no intercalation occured on the newly manufactured clay-tolerant PCE within the layers of Mnt, resulting in a greater sorption thickness and improved dispersion of the cements containing Na-Mnt.","PeriodicalId":10311,"journal":{"name":"Clay Minerals","volume":"56 1","pages":"117 - 125"},"PeriodicalIF":1.5,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45668274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. D. de Souza, Tammy Caroline Lima de Jesus, Rafael C. dos Santos, Lívia Melo Bomfim, L. Bertolino, Débora F. de Andrade, L. A. d´Avila, L. Spinelli
This work presents the results of the physical characterization of palygorskite and its adsorptive behaviour for three solvatochromic dyes (Nile blue chloride (NBC), methylene blue (MTB) and dithizone (DTZ)). Adsorption isotherms were used to determine the maximum adsorption of the solvatochromic dyes on the palygorskite. The characterization of palygorskite was carried out via mineralogical and chemical analysis with X-ray diffraction, X-ray fluorescence, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy, surface-charge measurement (ζ-potential), thermogravimetric analysis, textural analysis and cation-exchange capacity analysis. The material consists of palygorskite and quartz and its chemistry is dominated by SiO2, MgO and Fe2O3. The specific surface area and cation-exchange capacity of the palygorskite are 142 m2 g–1 and 41 cmol(+) kg–1, respectively. The SEM and TEM analyses showed a fibrous structure with fibres 20–100 nm long. The thermogravimetric analysis showed three endothermic events at 57.3°C, 171.8°C and 439.6°C. The adsorption capacities of the palygorskite for NBC (basic pH), MTB (basic pH) and DTZ (neutral pH) were 0.082, 0.013 and 0.102 g g–1, respectively. The adsorptions of NBC and MTB were fitted with the Langmuir isotherm model and the adsorption of DTZ was fitted with the Sips model.
本文介绍了坡缕石的物理性质及其对三种溶剂化变色染料（氯化尼罗蓝（NBC）、亚甲基蓝（MTB）和双硫腙（DTZ））的吸附行为。用吸附等温线测定了溶剂化变色染料在坡缕石上的最大吸附量。通过矿物学和化学分析，采用X射线衍射、X射线荧光、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、傅立叶变换红外光谱、表面电荷测量（ζ-电位）、热重分析、结构分析和阳离子交换容量分析，对坡缕石进行了表征。该材料由坡缕石和石英组成，其化学成分以SiO2、MgO和Fe2O3为主。坡缕石的比表面积和阳离子交换容量分别为142 m2 g–1和41 cmol（+）kg–1。SEM和TEM分析显示纤维结构为20–100 nm长。热重分析显示，在57.3°C、171.8°C和439.6°C下发生了三次吸热事件。坡缕石对NBC（碱性pH）、MTB（碱性pH值）和DTZ（中性pH值）的吸附容量分别为0.082、0.013和0.102 g g–1。NBC和MTB的吸附符合Langmuir等温线模型，DTZ的吸附符合Sips模型。
{"title":"Characterization of Brazilian palygorskite (Guadalupe region) and adsorptive behaviour for solvatochromic dyes","authors":"C. D. de Souza, Tammy Caroline Lima de Jesus, Rafael C. dos Santos, Lívia Melo Bomfim, L. Bertolino, Débora F. de Andrade, L. A. d´Avila, L. Spinelli","doi":"10.1180/CLM.2021.16","DOIUrl":"https://doi.org/10.1180/CLM.2021.16","url":null,"abstract":"This work presents the results of the physical characterization of palygorskite and its adsorptive behaviour for three solvatochromic dyes (Nile blue chloride (NBC), methylene blue (MTB) and dithizone (DTZ)). Adsorption isotherms were used to determine the maximum adsorption of the solvatochromic dyes on the palygorskite. The characterization of palygorskite was carried out via mineralogical and chemical analysis with X-ray diffraction, X-ray fluorescence, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy, surface-charge measurement (ζ-potential), thermogravimetric analysis, textural analysis and cation-exchange capacity analysis. The material consists of palygorskite and quartz and its chemistry is dominated by SiO2, MgO and Fe2O3. The specific surface area and cation-exchange capacity of the palygorskite are 142 m2 g–1 and 41 cmol(+) kg–1, respectively. The SEM and TEM analyses showed a fibrous structure with fibres 20–100 nm long. The thermogravimetric analysis showed three endothermic events at 57.3°C, 171.8°C and 439.6°C. The adsorption capacities of the palygorskite for NBC (basic pH), MTB (basic pH) and DTZ (neutral pH) were 0.082, 0.013 and 0.102 g g–1, respectively. The adsorptions of NBC and MTB were fitted with the Langmuir isotherm model and the adsorption of DTZ was fitted with the Sips model.","PeriodicalId":10311,"journal":{"name":"Clay Minerals","volume":"1 1","pages":"1-33"},"PeriodicalIF":1.5,"publicationDate":"2021-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47480274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cunjun Li, Minghao Wang, Zhaoliang Liu, Yanqi Xu, C. Zhou, Linjiang Wang
Microcapsules are successfully used in various applications such as self-healing, drug delivery and military camouflage. The shells of the microcapsules based on the traditional surfactant-stabilized emulsion template method are often single organic materials. The surfactants generally have insufficient stability against demulsification during preparation of the microcapsules. In the present study, kaolinite was used as an emulsifier for stabilizing Pickering emulsions and subsequently as an enhancer for forming microcapsules. Kaolinite-armoured polyurea microcapsules were fabricated based on the interfacial polymerization of isophorone diisocyanate at the oil–water interfaces of kaolinite-stabilized Pickering emulsions. The prepared microcapsules with core–shell structure were spherical and exhibited good dispersibility in anhydrous ethanol. The shell thickness (~0.5–1.0 μm) and diameter (~20.0–160.0 μm) of kaolinite-armoured polyurea microcapsules may be tailored by varying the dosages of isophorone diisocyanate and kaolinite and the emulsifying speed of the high-shear homogenizer. Hence, the encapsulation and release performance of microcapsules may be controlled. The kaolinite particles were embedded and armoured in a polyurea matrix. The formed kaolinite-embedded and -armoured polyurea structures might prolong the release of the encapsulated lipophilic Sudan Red (III) from 20 to 45 h. The microcapsules have controllable encapsulation and release characteristics for lipophilic compounds and are cost effective, making them suitable pesticides.
{"title":"Kaolinite-armoured polyurea microcapsules fabricated on Pickering emulsion: controllable encapsulation and release performance of a lipophilic compound","authors":"Cunjun Li, Minghao Wang, Zhaoliang Liu, Yanqi Xu, C. Zhou, Linjiang Wang","doi":"10.1180/CLM.2021.15","DOIUrl":"https://doi.org/10.1180/CLM.2021.15","url":null,"abstract":"Microcapsules are successfully used in various applications such as self-healing, drug delivery and military camouflage. The shells of the microcapsules based on the traditional surfactant-stabilized emulsion template method are often single organic materials. The surfactants generally have insufficient stability against demulsification during preparation of the microcapsules. In the present study, kaolinite was used as an emulsifier for stabilizing Pickering emulsions and subsequently as an enhancer for forming microcapsules. Kaolinite-armoured polyurea microcapsules were fabricated based on the interfacial polymerization of isophorone diisocyanate at the oil–water interfaces of kaolinite-stabilized Pickering emulsions. The prepared microcapsules with core–shell structure were spherical and exhibited good dispersibility in anhydrous ethanol. The shell thickness (~0.5–1.0 μm) and diameter (~20.0–160.0 μm) of kaolinite-armoured polyurea microcapsules may be tailored by varying the dosages of isophorone diisocyanate and kaolinite and the emulsifying speed of the high-shear homogenizer. Hence, the encapsulation and release performance of microcapsules may be controlled. The kaolinite particles were embedded and armoured in a polyurea matrix. The formed kaolinite-embedded and -armoured polyurea structures might prolong the release of the encapsulated lipophilic Sudan Red (III) from 20 to 45 h. The microcapsules have controllable encapsulation and release characteristics for lipophilic compounds and are cost effective, making them suitable pesticides.","PeriodicalId":10311,"journal":{"name":"Clay Minerals","volume":"1 1","pages":"1-30"},"PeriodicalIF":1.5,"publicationDate":"2021-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42665772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. M. J. Salgado-Campos, L. Bertolino, Francisco J. da Silva, J. Mendes, R. Neumann
Halloysite is a 1:1 dioctahedral clay mineral that has been studied widely for applications in nanotechnology and as a mineral exploration guide for recognizing regolith-hosted heavy rare earth element (HREE) deposits. In Brazil, pegmatites from the state of Rio de Janeiro have been catalogued, but their potential to host halloysite deposits has never been studied. After a mineral exploration programme, one pegmatite with considerable halloysite contents and economic potential was discovered. This study reports the mineralogical and chemical characterization of the halloysite of this pegmatite and evaluates the possibility of clay-adsorbed HREE deposits, like that in the Zudong (China) regolith-hosted HREE deposit. Seven samples were collected in horizontal channels. Bulk samples and clay fractions (<2 μm) were analysed by quantitative mineral analysis (X-ray diffraction/Rietveld method), chemical analysis (major elements by X-ray fluorescence and Y, U, Th and rare earth elements by inductively coupled plasma mass spectrometry), scanning electron microscopy, Fourier-transform infrared spectroscopy, particle-size analysis, nitrogen physisorption and cation-exchange capacity. Mixed polygonal/cylindrical halloysite-7Å in concentrations between 6.3 and 35.4 wt.% in bulk samples and between 58.0 and 89.8 wt.% in the clay fractions were identified in the pegmatite. The clay fractions presented an average chemical composition of 45.46 wt.% SiO2, 36.10 wt.% Al2O3, 14.62 wt.% loss on ignition and 1.04 wt.% Fe2O3, as well as technological properties close to those observed in world-class halloysite deposits such as Dragon Mine (USA) and Matauri Bay (New Zealand). The clay minerals did not present significant HREE contents.
{"title":"Mineralogy and chemistry of a new halloysite deposit from the Rio de Janeiro pegmatite province, south-eastern Brazil","authors":"V. M. J. Salgado-Campos, L. Bertolino, Francisco J. da Silva, J. Mendes, R. Neumann","doi":"10.1180/CLM.2021.8","DOIUrl":"https://doi.org/10.1180/CLM.2021.8","url":null,"abstract":"Halloysite is a 1:1 dioctahedral clay mineral that has been studied widely for applications in nanotechnology and as a mineral exploration guide for recognizing regolith-hosted heavy rare earth element (HREE) deposits. In Brazil, pegmatites from the state of Rio de Janeiro have been catalogued, but their potential to host halloysite deposits has never been studied. After a mineral exploration programme, one pegmatite with considerable halloysite contents and economic potential was discovered. This study reports the mineralogical and chemical characterization of the halloysite of this pegmatite and evaluates the possibility of clay-adsorbed HREE deposits, like that in the Zudong (China) regolith-hosted HREE deposit. Seven samples were collected in horizontal channels. Bulk samples and clay fractions (<2 μm) were analysed by quantitative mineral analysis (X-ray diffraction/Rietveld method), chemical analysis (major elements by X-ray fluorescence and Y, U, Th and rare earth elements by inductively coupled plasma mass spectrometry), scanning electron microscopy, Fourier-transform infrared spectroscopy, particle-size analysis, nitrogen physisorption and cation-exchange capacity. Mixed polygonal/cylindrical halloysite-7Å in concentrations between 6.3 and 35.4 wt.% in bulk samples and between 58.0 and 89.8 wt.% in the clay fractions were identified in the pegmatite. The clay fractions presented an average chemical composition of 45.46 wt.% SiO2, 36.10 wt.% Al2O3, 14.62 wt.% loss on ignition and 1.04 wt.% Fe2O3, as well as technological properties close to those observed in world-class halloysite deposits such as Dragon Mine (USA) and Matauri Bay (New Zealand). The clay minerals did not present significant HREE contents.","PeriodicalId":10311,"journal":{"name":"Clay Minerals","volume":"1 1","pages":"1-15"},"PeriodicalIF":1.5,"publicationDate":"2021-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65514668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhe Wang, Hong Li, Haiyan Chen, Juan Lv, Hao Leng, Junhui Xiao, Shuai Wang
Steam jet milling was applied for the first time to ultra-fine grind the filter cake (moisture content 23.80%) produced by a kaolin concentrator. The material was dehydrated and dried simultaneously during grinding, and the final ground sample met the moisture content requirement for powder products of <2%. The particle size of the ground kaolin samples decreased and the particle-size distribution was more concentrated, indicating that the steam jet milling was more effective for kaolin processing than the conventional dry grinding process. In addition, steam jet milling can improve the whiteness and decrease the crystal order of the samples, thus improving the kaolin properties in follow-up applications.
{"title":"Effects of grinding and dehydration on kaolin in a steam jet mill","authors":"Zhe Wang, Hong Li, Haiyan Chen, Juan Lv, Hao Leng, Junhui Xiao, Shuai Wang","doi":"10.1180/CLM.2021.18","DOIUrl":"https://doi.org/10.1180/CLM.2021.18","url":null,"abstract":"Steam jet milling was applied for the first time to ultra-fine grind the filter cake (moisture content 23.80%) produced by a kaolin concentrator. The material was dehydrated and dried simultaneously during grinding, and the final ground sample met the moisture content requirement for powder products of <2%. The particle size of the ground kaolin samples decreased and the particle-size distribution was more concentrated, indicating that the steam jet milling was more effective for kaolin processing than the conventional dry grinding process. In addition, steam jet milling can improve the whiteness and decrease the crystal order of the samples, thus improving the kaolin properties in follow-up applications.","PeriodicalId":10311,"journal":{"name":"Clay Minerals","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46556739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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