Characterization of waste. Kinetic testing for assessing acid generation potential of sulfidic waste from extractive industries

2013 ◽  
Keyword(s):  
Extractive Industries ◽  
Acid Generation ◽  
Kinetic Testing

Overview

2018 ◽  
Author(s):  
Grenville Astill
Keyword(s):  
Extractive Industries ◽  
Environmental Archaeology ◽  
Full Potential ◽  
New Techniques ◽  
Landscape Characterization ◽  
Archaeological Work ◽  
The Impact ◽  
Historic Landscape ◽  
Cultural Entities

This overview examines the different units of scale at which the medieval countryside has been studied, the ‘geographies’ of the title. It discusses the application of the term pays as distinctive environmental and cultural entities, archaeological work at the scale of the parish or township and the influence of new techniques and methodologies such as LiDAR and GIS. The impact of ‘big data’ projects such as the characterization of medieval rural settlement and Historic Landscape Characterization is highlighted, though some weaknesses are identified. The importance of specialized landscapes is stressed such as those set aside for hunting, seasonal activities, and the extractive industries. Finally, a plea is made for greater attention to chronological changes at different scales of study and for the full potential of environmental archaeology to be exploited by landscape projects.

scholarly journals Physical chemical characterization of historical mining waste and ARD prediction tests

2017 ◽  
Vol 18 ◽  
pp. 01031
Author(s):  
Antoneta Filcenco-Olteanu ◽  
Lena Alakangas ◽  
Antoio Fiuza ◽  
Marius Zlagnean ◽  
Nicolae Tomus
Keyword(s):  
Chemical Elements ◽  
Mine Waste ◽  
Chemical Characterization ◽  
Dissolved Metals ◽  
Acid Base ◽  
Metal Mining ◽  
Acid Generation ◽  
Waste Dumps ◽  
Baia Mare

There are thousands of historical mine tailings and metallurgical residues present on inactive metal mining sites which have been abandoned. However, the potential release of dissolved metals, acidity, or suspended particulates from mine-waste dumps can be a serious and long-lasting problem. A variety of environmental impacts may occur at this abandoned mine sites and leading the list is acid generation, which is one of the main problems from metal mining. The objective of the present study was to characterize and evaluate the Romanian historical tailing of Sasar-Red Valley, near Baia Mare. This involved physical and chemical characterization of the materials and its acid generating potential. Sasar tailing impoundment contains 8.5 million m3 of tailings and occupies an area of 32.5 hectares. Tailings samples were collected from different depths in three sampling points, and characterized by grain size, chemical elements concentration, elements distribution of elements in depth, paste pH, acid-base account and net acid generation tests. Acid base accounting (ABA) tests in conjunction with net acid generation (NAG) tests classified the samples into the category of ‘potentially acid generating’. This paper presents a synthesis of works performed in the Improve Resource Efficiency and Minimize Environmental Footprint (REMinE) project.

Characterization of the amiloride-sensitive Na+-H+ antiport of human neutrophils

1986 ◽  
Vol 250 (2) ◽  
pp. C283-C291 ◽  
Author(s):  
S. Grinstein ◽  
W. Furuya
Keyword(s):  
Rate Of Change ◽  
Human Neutrophils ◽  
Acid Generation ◽  
Buffering Power ◽  
Activated Neutrophils ◽  
Blood Neutrophils ◽  
Cytoplasmic Acidification ◽  
Cell Sizing ◽  
Na Uptake

In response to infection, neutrophils undergo a metabolic burst associated with a marked increase in acid generation. However, cytoplasmic pH (pHi) remains normal or even becomes slightly alkaline. Regulation of pHi is due, at least in part, to a Na+-H+ exchange mechanism. The basic properties of this antiport were investigated in human blood neutrophils using fluorescein derivatives as pHi indicators and by means of electronic cell sizing. Addition of external Na+ (Na+o) to acid-loaded cells resulted in intracellular alkalinization due to transmembrane H+ (equivalent) flux. The alkalinization was associated with Na+ uptake, and both processes were blocked by amiloride, suggesting Na+-H+ countertransport. The rate of amiloride-sensitive H+ efflux could be calculated from the rate of change of pHi, using a buffering power of 28 mmol X l-1 X pH unit-1, determined by titration with NH+4 or propionate-. The rate of Na+o-H+i exchange was a saturable function of Na+o (apparent Km = 73 mM). Forward (Na+o-H+i) exchange was inhibited by elevating external [H+] or internal [Na+] and competitively by amiloride (apparent Ki = 24 microM). The antiport was virtually inactive in unstimulated cells at pHi greater than or equal to 7.2 but was markedly stimulated by cytoplasmic acidification. This behavior is consistent with a role in pHi homeostasis. The possible mechanisms of stimulation of Na+-H+ countertransport in resting and activated neutrophils are discussed.

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