Minerals Engineering最新文献

{"title":"Mechanisms of gangue transport and recovery in Reflux flotation cells under varying bias flux and salinity conditions","authors":"Brady Wright,&nbsp;Pouria Amani,&nbsp;Kevin Galvin,&nbsp;Mahshid Firouzi","doi":"10.1016/j.mineng.2025.109765","DOIUrl":"10.1016/j.mineng.2025.109765","url":null,"abstract":"<div><div>This study investigates the transport mechanisms by which hydrophilic gangue particles report to the product stream in the Reflux Flotation Cell (RFC) under a range of bias fluxes and salinity conditions. Bias flux defined as the difference between the wash water flux and the product water flux was systematically varied to establish negative, zero, and positive net liquid flow relative to rising bubbles. Fine silica (D₉₀ = 68 μ m) was used as a model hydrophilic gangue material, with experiments conducted in both 0 and 1  M NaCl to represent freshwater and saline process water conditions. Under negative bias (no wash water), silica recovery was dominated by bulk entrainment, reaching ∼14 wt% in freshwater and slightly higher in saline conditions. At zero bias, where net liquid flow was neutral, bulk entrainment was significantly minimised and bubble surface entrainment became the dominant mechanism. Silica recovery in this regime increased from ∼6 % (no salt) to ∼8 % (1  M NaCl), attributed to salt-induced aggregation promoting surface entrainment. Under positive bias, the downward liquid flow effectively washed gangue particles from bubble surfaces, reducing recovery to below 1 wt% in both salt and no-salt systems. Quantitative decomposition of recovery data showed that salt enhanced both bulk entrainment under negative bias and washability under positive bias, due to the formation of loosely bound aggregates. Single-bubble experiments confirmed that salt promotes surface loading via aggregation, and that such aggregates can be detached by downward liquid flow. To further characterise RFC hydrodynamics, bubbly zone length and bubble size distributions were analysed in both the vertical and inclined sections. Results demonstrated the role of inclined channels in promoting bubble segregation, with implications for improved gangue rejection.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"234 ","pages":"Article 109765"},"PeriodicalIF":5.0,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145026690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reduction of saprolite nickel ore using methane-argon gas mixture with laboratory-scale simulated rotary kiln-electric furnace (RKEF) technology","authors":"Amalia Jihan Nabilah ,&nbsp;Bima Satritama ,&nbsp;Taufiq Hidayat ,&nbsp;Pekka Taskinen ,&nbsp;Imam Santoso ,&nbsp;Hamzah Kurniadani ,&nbsp;Zulfiadi Zulhan","doi":"10.1016/j.mineng.2025.109776","DOIUrl":"10.1016/j.mineng.2025.109776","url":null,"abstract":"<div><div>Saprolite nickel ore is typically processed using a pyrometallurgical route called Rotary Kiln-Electric Furnace (RKEF), which contributes to about 75 % of nickel production from laterite nickel ores. In RKEF technology, coal plays multiple roles as a reductant, fuel, and electricity source. Methane is a viable option as reductant and fuel for reducing CO₂ emissions in the nickel industry, particularly as a stopgap measure until hydrogen production can be scaled up. However, there has been limited research on using methane as a reductant in nickel production. This study aims to produce ferronickel from saprolite nickel ore through a laboratory-scale RKEF using methane gas. Initially, FactSage 8.2 was used to investigate the thermodynamics of the process. A series of laboratory experiments were carried out in two stages to simulate the RKEF process. It involved varying the reduction temperature (500–900 °C), reduction time (15–120 min), and gas composition (25 and 75 vol% CH₄/Ar) before each calcine was melted at 1550 °C for 2 h. The average composition of metals obtained was 71.3 % Fe and 14.3 % Ni. The results showed that methane can be used to produce ferronickel with a similar composition as commercial ferronickel.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"234 ","pages":"Article 109776"},"PeriodicalIF":5.0,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145044175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advances in iron and manganese removal technologies for sustainable copper-cobalt hydrometallurgy","authors":"Zhengyong Yang ,&nbsp;Yuchen Shi ,&nbsp;Jingyuan Xu ,&nbsp;Yiquan Yang ,&nbsp;Zhenyin Wang ,&nbsp;Hongfei Ba ,&nbsp;Yansheng Zhang ,&nbsp;Baojun Yang ,&nbsp;Yan Cai ,&nbsp;Jun Wang ,&nbsp;Jianyu Zhu ,&nbsp;Guanzhou Qiu ,&nbsp;Min Gan","doi":"10.1016/j.mineng.2025.109771","DOIUrl":"10.1016/j.mineng.2025.109771","url":null,"abstract":"<div><div>The global adoption of new energy vehicles has expanded rapidly in recent years, driving intensified use of cobalt in lithium battery technologies. This trend has triggered a substantial rise in worldwide demand for both cobalt resources. Therefore, cobalt recycling is crucial for sustainable resource management and environmental protection. The presence of impurities, such as iron and manganese, adversely affects the subsequent recovery and application of cobalt. This paper examines technologies and methods for removing these impurities prior to cobalt recovery. It systematically analyzes various iron removal techniques and discusses recent developments, and evaluates their economic feasibility in terms of capital investment, operating costs, and environmental risks. Among iron removal methods, the jarosite process demonstrates higher cost-effectiveness for industrial-scale applications, while the hematite process requires stringent operational conditions. Additionally, it compares and evaluates manganese removal technologies, such as precipitation, ion exchange, electrolysis, and extraction methods. Moreover, this paper presents other treatment methods that can remove and separate iron and manganese simultaneously: neutralization precipitation and SO₂/O₂ oxidative precipitation. The SO₂/O₂ oxidative precipitation method offers a simplified and eco-friendly alternative to conventional techniques. The paper also addresses cobalt precipitation techniques, including primary cobalt deposit and secondary cobalt deposit, pressurized ammonia distillation, and liquid-phase reduction precipitation. In general, this paper summarizes the various methods of iron and manganese removal, and analyzes the limitations and future trends, this provides new insights for advancing iron and manganese removal technologies in cobalt hydrometallurgy.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"234 ","pages":"Article 109771"},"PeriodicalIF":5.0,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145026689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A spatio-temporal graph neural network with masked self-supervision for precise anomaly severity measurement of vibrating screens in mineral processing","authors":"Yuxin Wu ,&nbsp;Ziqi Lv ,&nbsp;Xuan Zhao ,&nbsp;Yao Cui ,&nbsp;Qiqi Zou ,&nbsp;Yanbo Liu ,&nbsp;Zhen Bao ,&nbsp;Weidong Wang","doi":"10.1016/j.mineng.2025.109764","DOIUrl":"10.1016/j.mineng.2025.109764","url":null,"abstract":"<div><div>Accurately quantifying the anomaly severity of vibrating screens is crucial for ensuring the stable operation of mining production systems such as coal preparation plants. However, this task faces three major challenges: (1) Traditional methods struggle to learn robust health state baselines from normal operating data; (2) Vibration signals exhibit multi-scale temporal patterns and dynamic coupling relationships between sensors, posing difficulties for spatiotemporal feature modelling; (3) There is a lack of effective anomaly severity quantification mechanisms. To address these issues, this paper proposes a Spatio-Temporal Graph Neural Network with Masked Self-Supervision (STGNN-MSS). The method tackles the aforementioned challenges through three modules: First, the self-supervised pre-training module employs a Transformer-based masked autoencoder to learn deep temporal representations from normal data through a regression-classification dual-task framework; Second, the spatio-temporal feature learning module combines multi-scale hypergraph networks and dynamic graph convolutional networks to capture high-order dependencies at different temporal scales and dynamic spatial coupling between sensors, respectively; Finally, the anomaly severity detection module adopts a prediction-reconstruction dual-task framework and introduces a KL divergence-based distribution deviation metric to achieve precise quantification of anomaly severity. Experimental results demonstrate that STGNN-MSS achieves an F1 score of 0.9798 and an AUC value of 0.94 on the vibrating screen dataset, representing improvements of 11.2 % and 5.6 % over the best baseline methods, respectively, validating the effectiveness of the proposed method.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"234 ","pages":"Article 109764"},"PeriodicalIF":5.0,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145019142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advancements and applications of numerical simulation in enhancing the efficiency of low-intensity magnetic separators","authors":"Liwei Wu, Dongdong Tang, Jinlei Wen, Minghui Gong, Feiwang Wang, Huixin Dai","doi":"10.1016/j.mineng.2025.109750","DOIUrl":"https://doi.org/10.1016/j.mineng.2025.109750","url":null,"abstract":"Magnetite is the core of the steel industry and a pillar of economic development in resource-based regions. Low-intensity magnetic separation (LIMS) is a highly effective method for separating magnetite. However, studies on LIMS mechanism and the optimization and development of equipment have progressed slowly due to high complexity of the magnetization mechanism of magnetic ore particles during the separation process, the ambiguity of the interaction mechanism between multi-physical fields and mineral particles, and the lack of characterization and observation methods in the dynamic separation process. Recently, advancements in numerical simulation have significantly contributed to studies on prediction of separation results in dry and wet low-intensity magnetic separation, equipment optimization and development, interaction mechanisms between multi-physical fields and mineral particles in the dynamic separation process, and the interaction mechanisms between mineral particles. These studies outline the problems that constrain the application of numerical simulations in LIMS, and proposes the future research directions of numerical simulation technology in the field of weak magnetic separation.","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"38 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145009086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on hydrogen reduction behavior of Hainan Hematite: Kinetic and microstructural evolution from a green resource processing perspective","authors":"Lingbo Zhao ,&nbsp;Bing Zhao ,&nbsp;Peng Gao ,&nbsp;Xiangyan Kong ,&nbsp;Yuexin Han","doi":"10.1016/j.mineng.2025.109769","DOIUrl":"10.1016/j.mineng.2025.109769","url":null,"abstract":"<div><div>Hainan hematite is a typical refractory iron ore with low porosity and high structural compactness, which severely limits its reactivity during hydrogen-based reduction. To address this challenge, a comprehensive investigation was conducted to examine its reduction behavior from multiple perspectives. Unlike conventional hematite, Hainan hematite exhibited a distinct two-stage kinetic behavior, which could not be fully described using traditional models. A segmental kinetic analysis was therefore applied, revealing a transition from chemical reaction control to diffusion control. The transformation from hematite to magnetite proceeded slowly at low temperatures but was significantly accelerated by elevated temperatures or extended reduction durations. Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometry (VSM) analyses revealed that the formation of internal cracks and the development of porous product layers enhanced hydrogen diffusion and magnetic phase enrichment, particularly at higher degrees of reduction. Brunauer–Emmett–Teller (BET) analysis further confirmed the progressive evolution of the pore network and highlighted the interplay between fine pore formation and crack propagation. These findings provide, for the first time, a detailed kinetic and microstructural interpretation of hydrogen-based reduction behavior in Hainan hematite, offering new insight into the reduction mechanism of refractory iron ores. The results contribute to a better understanding of the coupling among reaction kinetics, phase transformation, and pore structure evolution, and offer theoretical guidance for the advancement of low-carbon metallurgical technologies.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"234 ","pages":"Article 109769"},"PeriodicalIF":5.0,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145019141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Semi-industrial test of vanadium extraction from stone coal vanadium ore by high-pressure roll-suspension roasting-solidification leaching process","authors":"Zhe Bai ,&nbsp;Zhiming Li ,&nbsp;Tingbo Zhou ,&nbsp;Mingxing Wang ,&nbsp;Shuai Yuan ,&nbsp;Yuexin Han ,&nbsp;Jianping Jin","doi":"10.1016/j.mineng.2025.109757","DOIUrl":"10.1016/j.mineng.2025.109757","url":null,"abstract":"<div><div>Rich vanadium resources are stored in stone coal. Compared with the high temperature, high pressure, and high acid concentration conditions required by the direct leaching process, the roasting-leaching process demonstrates significant advantages. Roasting liberates and oxidizes the vanadium in the ore, allowing it to be recovered through a subsequent leaching process. This approach not only reduces the severity of the operating conditions but also broadens the application scope. The high-pressure roll-suspension roasting-solidification leaching process has been proposed to enhance vanadium leaching. Semi-industrial test results showed that qualified feed was obtained under the feed rate of 50 kg, the feed particle size of −15 mm, the roller surface pressure of 13–14 MPa, and the roller speed of 18 r/min. The suspension roasting system achieved stable and effective operation under the processing capacity of 90 kg/h, the air consumption of 28.0 m³/h, the CO₂ consumption of 8.0 m³/h, and the temperature of ≥ 890 °C in the primary and secondary reactors. Under the acid mixing temperature of 130 °C, acid dosage of 40 %, curing time of 6 h, and leaching time of 3 h, the V₂O₅ leaching rate of 83.79 % was obtained. After roasting, the cracks of the ore increase and elongate, the micropores enlarge and transform into open internal pores, the surface roughness of the ore undergoes further changes.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"234 ","pages":"Article 109757"},"PeriodicalIF":5.0,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145010547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Composite lixiviant synergy for ionic rare earth extraction: Dual-perspective mechanistic insights from metabolomics and mineralogical characterization","authors":"Yaru Duan ,&nbsp;Lingyan Li ,&nbsp;Jiale You ,&nbsp;Haitao Wang ,&nbsp;Yun Fang ,&nbsp;Jun Wang ,&nbsp;Yang Liu ,&nbsp;Ruan Chi ,&nbsp;Chunqiao Xiao","doi":"10.1016/j.mineng.2025.109766","DOIUrl":"10.1016/j.mineng.2025.109766","url":null,"abstract":"<div><div>Rare earth elements are scarce materials that are crucial in new technology industries; however, realizing their efficient and environmentally friendly mining and utilization is challenging. In this study, response surface methodology was employed to optimize a fermentation medium of <em>Bacillus thuringiensis</em> (W-50) and its fermentation broth, which were compounded with magnesium acetate to create a composite lixiviant. The composite lixiviant, formulated after media optimization, was found to significantly enhance the leaching efficiency. Untargeted metabolomics was employed to analyze the changes in metabolites before and after leaching, and various characterization techniques were used to examine the changes in the ore after leaching. The results showed that a rare earth leaching rate of 98.6 % could be achieved when the initial concentration of C₄H₆O₄Mg in the composite lixiviant was 0.2 mol/L, the initial pH was 4, and the leaching solid–liquid ratio was 1:3. The metabolomics results indicated that organic acids and their derivatives played important roles in the leaching process. This research provides a useful reference for the development of a composite lixiviant for ionic rare earth ores and provides a framework for advancing environmental protection and operational efficiency in the rare earth mining industry.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"234 ","pages":"Article 109766"},"PeriodicalIF":5.0,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145009091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recovery of rhenium from dust and waste acid generated from copper-molybdenum smelting: A critical review","authors":"Xingfei Zhang ,&nbsp;Zihao Sun ,&nbsp;Xianzhong Bu ,&nbsp;Wei Sun ,&nbsp;Haisheng Han ,&nbsp;Xuewen Song ,&nbsp;Sen Wang ,&nbsp;Jiwei Xue ,&nbsp;Chonghui Zhang","doi":"10.1016/j.mineng.2025.109761","DOIUrl":"10.1016/j.mineng.2025.109761","url":null,"abstract":"<div><div>Rhenium (Re), as a scarce metal, is primarily essential for producing high-temperature superalloys and platinum–rhenium catalysts, which together consume over 90 % of global Re production. As a significant aerospace power, China relies on Re imports for more than 50 % of its demand. This paper comprehensively reviews the Re separation and extraction from secondary resources, focusing on copper-molybdenum smelting dust and waste acid, which account for over 80 % of Re occurrence. Recovery process needs to consider variations in raw materials and develop tailored technologies. The main industrial route for dust pretreatment involves pyrometallurgical processing followed by solution leaching. However, it faces issues such as high energy consumption and low leaching selectivity. Achieving deep recovery from leaching solution lies in the high-precision separation of Re from impurities. Both chemical and non-chemical precipitation methods are widely used. Non-chemical precipitation typically achieves recovery rates above 95 % but requires weakly acidic or neutral conditions, necessitating prior wastewater treatment. Chemical precipitation is simple, efficient, and rapid for strongly acid wastewater, but the traditional precipitation process often leads to co-precipitation of impurity ions, which reduces product purity. Effective control of sulfur ion concentration during sulfide precipitation is crucial for improving separation precision. The selective precipitation can be optimized by finely adjusting the properties and addition methods of the sulfurizing agent. This paper proposes a new approach to Re recovery through three key dimensions: source control-process enhancement-precise separation. It also addresses the current challenges and outlines future directions for improving Re recovery from smelting dust and waste acid, guiding its deep, efficient separation and high-value utilization in metallurgical by-products.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"234 ","pages":"Article 109761"},"PeriodicalIF":5.0,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145019140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Supercritical CO2 extraction of critical and strategic metals: a review of mechanisms, factors and application","authors":"Qingbin Liu,&nbsp;Shuai Yuan,&nbsp;Yuexin Han,&nbsp;Delong Yang,&nbsp;Pengcheng Tian,&nbsp;Hongquan Wei","doi":"10.1016/j.mineng.2025.109759","DOIUrl":"10.1016/j.mineng.2025.109759","url":null,"abstract":"<div><div>With the rapid development of new energy and manufacturing industries, the demand for critical and strategic metals such as rare earths, lithium, cobalt, nickel, manganese, palladium, copper, and uranium has increased significantly. In the context of a low-carbon economy, the green and efficient recovery of these essential resources has received growing attention. Supercritical carbon dioxide (scCO₂) is regarded as a highly selective, environmentally friendly, and promising extraction technology. It is considered effective for addressing the environmental and energy challenges present in conventional extraction processes. In this paper, a detailed overview of the extraction principles and equipment related to scCO₂ is provided. Recent progress in the extraction of strategic metals using scCO₂ is systematically summarized. Key factors influencing extraction efficiency, including process conditions and additives, are reviewed along with their underlying mechanisms. Finally, the prospects for further development of scCO₂ extraction are discussed from the perspectives of extraction mechanisms, extractant design, and equipment optimization. Through this review, new insights are offered for the green and efficient utilization of critical and strategic metal resources.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"234 ","pages":"Article 109759"},"PeriodicalIF":5.0,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145003557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}