ore leaching

(noun)

The process of recovering metals from ores by using a number of different techniques.

Examples of ore leaching in the following topics:

  • Microbial Ore Leaching

    • Microbial ore leaching is the process in which microorganisms are used to extract metals from ores.
    • Microbial ore leaching (bioleaching) is the process of extracting metals from ores with the use of microorganisms.
    • very efficiently extract metals when their concentration in the ore is low.
    • Bacteria perform the key reaction of regenerating the major ore oxidizer which in most cases is ferric iron as well as further ore oxidation.
    • When fungi are used, the leaching mechanism is different.
  • Oligotrophs

    • Oligotrophic environments include deep oceanic sediments, caves, glacial and polar ice, deep subsurface soil, aquifers, ocean waters, and leached soils.
    • An ecosystem or environment is said to be oligotrophic if it offers little to sustain life.
    • The term is commonly utilized to describe environments of water, ice, air, rock or soil with very low nutrient levels.
  • Metallurgy

    • Hydrometallurgy describes the process of extracting metals from ores using aqueous solutions.
    • The most common hydrometallurgical process is leaching, which involves the dissolution of the valuable metals into the aqueous solution.
    • Here, the coordination chemistry and solubility of the compound can become very important, as one attempts to precipitate a mineral (metal) of interest over the other metals in the solution or attempts to selectively leach one desired mineral over the others present in the sample.
    • Solids containing valuable metals are reacted to form intermediate compounds for further processing or converted into their elemental or metallic state.
    • Electrowinning is an electrolysis process used to recover metals in aqueous solution, usually as the result of an ore having undergone one or more hydrometallurgical processes.
  • Extractive Metallurgy

    • The grade or concentration of an ore mineral, or metal, as well as its form of occurrence, will directly affect the costs associated with mining it.
    • The process of ore formation is called ore genesis.
    • In order to convert a metal oxide or sulfide to a purer metal, the ore must be reduced physically, chemically, or electrolytically.
    • After mining, large pieces of the ore feed are broken through crushing and/or grinding.
    • The most common hydrometallurgical process is leaching, which involves dissolution of the valuable metals into the aqueous solution.
  • Prokaryotes and Environmental Bioremediation

    • Microbial bioremediation is the use of prokaryotes (or microbial metabolism) to remove pollutants.
    • Bioremediation has been used to remove agricultural chemicals (pesticides, fertilizers) that leach from soil into groundwater and the subsurface.
  • The Carbon Cycle

    • The most efficient type of respiration, aerobic respiration, requires oxygen obtained from the atmosphere or dissolved in water.
    • On land, carbon is stored in soil as a result of the decomposition of living organisms or the weathering of terrestrial rock and minerals.
    • This carbon can be leached into the water reservoirs by surface runoff.
    • A non-renewable resource is either regenerated very slowly or not at all.
    • Carbon is released as carbon dioxide when a volcano erupts or from volcanic hydrothermal vents.
  • Biogeochemical Cycles

    • Energy flows directionally through ecosystems, entering as sunlight (or inorganic molecules for chemoautotrophs) and leaving as heat during the many transfers between trophic levels.
    • Water can be liquid on the surface and beneath the surface or frozen (rivers, lakes, oceans, groundwater, polar ice caps, and glaciers) or exist as water vapor in the atmosphere .
    • For example, the movement of water is critical for the leaching of nitrogen and phosphate into rivers, lakes, and oceans.
    • Thus, mineral nutrients are cycled, either rapidly or slowly, through the entire biosphere, from one living organism to another, and between the biotic and abiotic world.
    • It is important for leaching certain components of organic matter into rivers, lakes, and oceans, and is a reservoir for carbon.
  • The Phosphorus Cycle

    • In addition to phosphate runoff as a result of human activity, natural surface runoff occurs when it is leached from phosphate-containing rock by weathering, thus sending phosphates into rivers, lakes, and the ocean.
    • A dead zone is an area within a freshwater or marine ecosystem where large areas are depleted of their normal flora and fauna.
  • Calcium and Phosphate Balance Regulation

    • Ninety-nine percent or more is deposited in bone and the remainder plays a vital role in nerve conduction, muscle contraction, hormone release and cell signalling.
    • This hormone also causes phosphate to leach out of bone.
  • Soaps & Detergents

    • Such molecules are termed amphiphilic (Gk. amphi = both) or amphipathic.
    • Fatty acids made up of ten or more carbon atoms are nearly insoluble in water, and because of their lower density, float on the surface when mixed with water.
    • To summarize, the presence of a soap or a detergent in water facilitates the wetting of all parts of the object to be cleaned, and removes water-insoluble dirt by incorporation in micelles.
    • Before sodium hydroxide was commercially available, a boiling solution of potassium carbonate leached from wood ashes was used.
    • These problems have been alleviated by the development of synthetic amphiphiles called detergents (or syndets).
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