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Recovery of metals and other beneficial products from coal fly ash： a sustainable approach for fly ash management

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International Journal of Coal Science & Technology 2016年第3期3卷 267-283页

作者： Prafulla Kumar Sahoo Kangjoo Kim M. A. Powell Sk Md Equeenuddin Vale Institute of Technology Baventura da Silva BelemPara 66055-090 Brazil Department of Environmental Engineering Kunsan NationalUniversity Jeonbuk 573-701 Republic of Korea prometeo SDIC Secretary of Higher Education ScienceTechnology and Innovation (SENESCYT) Quito Ecuador Department of Mining Engineering National Institute ofTechnology Rourkela Orissa 769008 India

Increasing production and disposal of coal fly ash （CFA） is a matter of serious environment concern. However, CFA contains various beneficial metals and mineral matters whose demand is increasing in the industrialized world, while natural supplies are diminishing. Therefore, recovery of these potential resources from CFA can be an alternative way to save mineral resources, as well as to reduce the environmental burden of CFA disposal. There are numerous methods developed for the recovery of beneficial products from CFA. Based on the US patents and journal literatures, the present review describes the recovery status and technologies of major elements such as Al, Si, Fe and Ti, and trace elements such as V, Ga, Ge, Se, Li, Mo, U, Au, Ag, Pt groups and rare earth elements （REEs） and other beneficial products such as magnetic materials, cenospheres, and unburned carbon from CFA. It also highlights the recovery efficiency and drawbacks for their extraction, and suggests future research to develop satisfactory results in terms of selective recovery and purification.

关键词： Coal fly ash Beneficial elements Recovery Hydrometallurgical methods Extraction efficiency

Saturated Hydraulic Conductivity Changes with Time and Its Prediction at SAR and Salinity in Quevedo Region Soils

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Journal of Water Resource and Protection 2014年第17期6卷 1561-1573页

作者： Abdelmonem Mohamed Amer Carmen Suarez Felix Valverde Roberto Carranza Leonardo Matute Gabriel Delfini SENESCYT Prometeo Project Quito Ecuador Department of Soil Science Faculty of Agriculture Menoufia University Shebin El-Kom Egypt Faculty of Agriculture Quevedo State Technical University-UTEQ Quevedo Ecuador

Darcy’s law is applied to describe the steady flow processes in which the flux remains constant with time along the conducting system. Due to the dispersion and migration of colloidal particles and lodging in the soil pores the reduction in hydraulic conductivity occurs with time in particular when the soil and the percolating solution are affected by electrolyte concentration. Hence, the aim of this study is to find empirical equations that can be used to predict the flux with time. Data for the effluent volume versus time (up to 6 hours) which was collected for three soils (located at Quevedo-Los Rios region) treated by two salt solutions (5 and 50 meq/l) with different SAR values were used to test certain mathematical forms of equations. Only four empirical equations were found to perfectly fit the data (flux vs time) whereas, fitting the calculated and measured data of the hydraulic conductivity for all soils produced regression factors R2 ≥ 0.99. So, these equations can be applied to predict the hydraulic conductivity and to characterize the flow process at saturated conditions of the studied soils with great confidence. The Hoerl function model was the best of all equations for application as the fitting degrees were almost perfect for all studied soils at 5 and 50 meq/l. It was observed for all equations that one of the fitting parameters would always represent the initial hydraulic conductivity (Kos) that was evaluated graphically at zero time by extrapolation.

关键词： Saturated Hydraulic Conductivity Empirical Models Effluent Volume and SAR Linear & Nonlinear Flux

A Review of the Production Cycle of Titanium Dioxide Pigment

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Materials Sciences and Applications 2014年第7期5卷 441-458页

作者： Manuel Jesús Gázquez Juan Pedro Bolívar Rafael Garcia-Tenorio Federico Vaca Departamento de Física Aplicada Universidad de HuelvaHuelvaEspana Departamento de Química Proyecto PrometeoUniversidad Técnicas Particular de Loja(UTPL)LojaEcuador Departamento de Física Aplicada II Universidad de SevillaSevillaEspaña

Titanium is a very important element for several industrial applications, being one of the ninth most abundant elements in the Earth’s crust (0.63% wt). In this work it will discuss the different mining and industrial activities involved in the production of titanium dioxide. The first step analyzed will treat about the beneficiation mining process of titanium mineral, and secondly, it will discuss the two main processes of the TiO2 manufacturing (sulphate and chloride routes). In addition, we will show different uses of the titanium dioxide pigment as filler in paper, plastics and rubber industries and as flux in glass manufacture, etc. Finally, we will show that the old wastes are currently called co-products since they were valorized, being commercialized by the Spanish industry of TiO2 production in different fields such as agriculture, civil engineering, or cement manufacturing.

关键词： Titanium Minerals Titanium Dioxide Pigment Properties and Uses of Tio2 Valorization of Co-Products

Critical analysis of the definition of severe dengue, based on the Ecuador outbreak in 2012

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Open Journal of Epidemiology 2014年第1期4卷 36-38页

作者： Natalia Romero Sandoval Pablo Lozano Jacqueline Cevallos Virginia Ruiz Miguel Martín Facultad de Ciencias Médicas Universidad Central del Ecuador Quito Ecuador Grups de Recerca d’ Amèrica i àfrica Llatines (GRAAL) Quito Ecuador Ministerio de Salud Pública de Ecuador Quito Ecuador Programa prometeo Secretaría Nacional de Ciencia y Tecnología (SENESCYT) Universidad Yachay Quito Ecuador

Of the 238 cases reported to the Ecuador Health Authorities in 2012 as severe dengue, only 53.3% met diagnostic criteria. The definition of severe dengue should be based on more precise criteria. Information about com... 详细信息

关键词： Severe Dengue Dengue Hemorrhagic Fever Fatality Rate