Leaching


The deposition of a clastic rock is preceded by the weathering and transport ot material. Mechanical weathering will be Induced if a rock is exposed to severe temperature changes or freezing of water in pores and cracks (e.g. in some desert environments). The action of plant roots forcing their way into bedrock is another example of mechanical weathering. Substances (e.g. acid waters) contained in surface waters can cause chemical weathering. During this process minerals are dissolved and the less stable ones, like feldspars are leached. Chemical weathering is particularly severe in tropical climates.  [c.76]

Large copper ore deposits are found in the U.S., Chile, Zambia, Zaire, Peru, and Canada. The most important copper ores are the sulfides, the oxides, and carbonates. From these, copper is obtained by smelting, leaching, and by electrolysis.  [c.62]

Systematic-judgmental sampling scheme for monitoring the leaching of pollutants from a landfill. Sites where samples are collected are represented by the solid dots.  [c.186]

Bacterial cellulose Bacterial leaching Bacterial removal Bacteria, luminous Bactericide  [c.85]

Leached glass fibers Leaching  [c.555]

Adams catalyst, platinum oxide, Pt02 H20. Produced by fusion of H2PtCl6 with sodium nitrate at 500-550 C and leaching of the cooled melt with water. Stable in air, activated by hydrogen. Used as a hydrogenation catalyst for converting alkenes to alkanes at low pressure and temperature. Often used on Si02  [c.15]

While Eq. III-18 has been verified for small droplets, attempts to do so for liquids in capillaries (where Rm is negative and there should be a pressure reduction) have led to startling discrepancies. Potential problems include the presence of impurities leached from the capillary walls and allowance for the film of adsorbed vapor that should be present (see Chapter X). There is room for another real effect arising from structural peiturbations in the liquid induced by the vicinity of the solid capillary wall (see Chapter VI). Fisher and Israelachvili [19] review much of the literature on the verification of the Kelvin equation and report confirmatory measurements for liquid bridges between crossed mica cylinders. The situation is similar to that of the meniscus in a capillary since Rm is negative some of their results are shown in Fig. III-3. Studies in capillaries have been reviewed by Melrose [20] who concludes that the Kelvin equation is obeyed for radii at least down to 1 fim.  [c.54]

The reports were that water condensed from the vapor phase into 10-100-/im quartz or pyrex capillaries had physical properties distinctly different from those of bulk liquid water. Confirmations came from a variety of laboratories around the world (see the August 1971 issue of Journal of Colloid Interface Science), and it was proposed that a new phase of water had been found many called this water polywater rather than the original Deijaguin term, anomalous water. There were confirming theoretical calculations (see Refs. 121, 122) Eventually, however, it was determined that the micro-amoimts of water that could be isolated from small capillaries was always contaminated by salts and other impurities leached from the walls. The nonexistence of anomalous or poly water as a new, pure phase of water was acknowledged in 1974 by Deijaguin and co-workers [123]. There is a mass of fascinating anecdotal history omitted here for lack of space but told very well by Frank [124].  [c.248]

Although alloying can improve corrosion resistance, brass and steel are not completely resistant to attack and often undergo a fonn of corrosion known as selective corrosion (also called de-alloying or leachmg). Dealloying consists of the segregation of one alloy component to the surface, followed by tlie removal of this surface component tln-ough a corrosion reaction. De-zincification is the selective leaching of zinc from brasses in an aqueous solution. The consequences of leaching are that mechanical and chemical properties change with compositional changes in the alloy.  [c.923]

After comminution, soluble impurities either inlrerent to tire raw materials or introduced during processing can be extracted by washing (e.g. witli water), followed by filtration [6, 21]. Chemical leaching and magnetic separation are also used to purify raw materials. In a more specialized process, a frothing agent can be used to promote differential adsorjDtion of impurity particles onto gas bubbles to separate out tire desired product [23].  [c.2765]

A suspension of 7.5 grams LAH in 500ml anhydrous Et20 was magnetically stirred, and heated in an inert atmosphere to a gentle reflux. The condensing Et20 leached out a total of 9.8 g 2-nitro-  [c.175]


See pages that mention the term Leaching : [c.18]    [c.97]    [c.171]    [c.236]    [c.416]    [c.2785]    [c.185]    [c.79]    [c.85]    [c.123]    [c.153]    [c.179]    [c.180]    [c.193]    [c.193]    [c.195]    [c.248]    [c.251]    [c.268]    [c.268]    [c.306]    [c.306]    [c.311]    [c.417]    [c.427]    [c.503]    [c.504]    [c.504]    [c.504]    [c.504]    [c.555]    [c.599]    [c.656]    [c.714]    [c.715]    [c.803]    [c.809]    [c.873]    [c.910]    [c.944]   
Corrosion, Volume 2 (2000) -- [ c.2 , c.120 ]