Economics by-products

Socialists abandoned their long-held contention that racial oppression was strictly an economic by-product of capitalism, and now took up the cudgel against lynching and Jim Crow.40... 

Utilization. For example, Be and the chalcophile elements, As, Cd, Hg, Pb, and Se, which are released during coal combustion or leached from coal waste products, can present significant environmental hazards halogens such as Cl and F can cause severe boiler corrosion and volatilized Ni, Ti, or V can cause corrosion and pitting of metal surfaces. On the positive side, some trace elements (e.g., Ge, Zn, U, and Au) may eventually prove to be economic by-products of coal utilization, while other elements (e.g., B) may be useful in helping to understand depositional environments and to correlate coal seams (7.8). 

As indicated above, this reaction proceeds rapidly and efficiently and can be relatively selective with lower extraction efficiency for zinc and copper sulfides. However, there may be concerns with low extractions for silver and gold, which are key economic by-products for lead extraction. For this reason an aggressive leach is preferred, which then necessitates comprehensive purification procedures. 

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See also in sourсe #XX -- [ , , , , ]

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