Chimborazo Copper Deposit, Region II, Chile; Exploration and Geology

Economical recovery of copper metal from leach liquors has been carried out by the simple process of cementing copper onto a suitable substrate metal, such as scrap-iron, since the 16th century. The process has, however, a major drawback of consuming more iron than stoichiometrically needed by the reaction.Therefore, many research groups started looking into the process more closely. Though it is accepted that the structural characteristics of the resultant copper deposit cause changes in reaction rates for various experimental conditions, not many systems have been systematically investigated. This paper examines the deposit structures and the kinetic data, and explains the correlations between them.A simple cementation cell along with rotating discs of pure iron (99.9%) were employed in this study to obtain the kinetic results The resultant copper deposits were studied in a Hitachi Perkin-Elmer HHS-2R scanning electron microscope operated at 25kV in the secondary electron emission mode.

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Electrochemical nucleation and growth of copper on iron and aluminum: A TEM study of industrial copper cementation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109410 ◽

1978 ◽

Vol 36 (1) ◽

pp. 454-455

Author(s):

L.E. Murr ◽

V. Annamalai

Keyword(s):

Metal Surface ◽

Copper Deposit ◽

Nucleation And Growth ◽

16Th Century ◽

Electrochemical Reactions ◽

Mine Shaft ◽

De Re ◽

Copper Precipitation ◽

Electrochemical Nucleation ◽

Interesting System

Georgius Agricola in 1556 in his classical book, “De Re Metallica”, mentioned a strange water drawn from a mine shaft near Schmölnitz in Hungary that eroded iron and turned it into copper. This precipitation (or cementation) of copper on iron was employed as a commercial technique for producing copper at the Rio Tinto Mines in Spain in the 16th Century, and it continues today to account for as much as 15 percent of the copper produced by several U.S. copper companies.In addition to the Cu/Fe system, many other similar heterogeneous, electrochemical reactions can occur where ions from solution are reduced to metal on a more electropositive metal surface. In the case of copper precipitation from solution, aluminum is also an interesting system because of economic, environmental (ecological) and energy considerations. In studies of copper cementation on aluminum as an alternative to the historical Cu/Fe system, it was noticed that the two systems (Cu/Fe and Cu/Al) were kinetically very different, and that this difference was due in large part to differences in the structure of the residual, cement-copper deposit.

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Localization of cell-surface and basement-membrane heparan-sulfate proteoglycans using the malaria circumsporozoite protein

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100169201 ◽

1994 ◽

Vol 52 ◽

pp. 294-295

Author(s):

U. Frevert ◽

S. Sinnis ◽

C. Cerami ◽

V. Nussenzweig

Keyword(s):

Heparan Sulfate ◽

Protein A ◽

Kidney Tissue ◽

Plasmodium Species ◽

Its Region ◽

Basement Membranes ◽

Heparan Sulfate Proteoglycans ◽

Infected Mosquito ◽

Complement Components ◽

Region Ii

Malaria sporozoites, which invade hepatocytes within minutes after transmission by an infected mosquito, are covered with the circumsporozoite (CS) protein, which in all Plasmodium species contains the conserved region II-plus. This region is also found as a cell-adhesive motif in a variety of host proteins like thrombospondin, properdin and the terminal complement components.The CS protein with its region II-plus specifically binds to heparan sulfate proteoglycans (HSPG) on the basolateral surface of hepatocytes in the space of Disse (FIG. 1), to certain basolateral cell membranes and basement membranes of the kidney (FIG. 2) as well as to heparin in the granules of connective tissue mast cells. The distribution of the HSPG receptors for the CS protein was examined by incubation of Lowicryl K4M or LR White sections of liver and kidney tissue with the recombinant CS ligand, whose binding sites were detected with a monoclonal anti-CS antibody and protein A gold.

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