Search results
Results from the WOW.Com Content Network
Pyrite oxidation is sufficiently exothermic that underground coal mines in high-sulfur coal seams have occasionally had serious problems with spontaneous combustion. [47] The solution is the use of buffer blasting and the use of various sealing or cladding agents to hermetically seal the mined-out areas to exclude oxygen.
Permineralization is a process of fossilization of bones and tissues in which mineral deposits form internal casts of organisms. Carried by water, these minerals fill the spaces within organic tissue. Because of the nature of the casts, permineralization is particularly useful in studies of the internal structures of organisms, usually of ...
Consequently, acid sulfate soil samples should be immediately cooled to < 4°C to slow oxidation; and samples containing monosulfidic material should be immediately frozen (e.g., using a portable freezer or liquid nitrogen). [31] The use of dry ice is recommended as the gaseous carbon dioxide should further hinder oxidation.
Plant cells with visible chloroplasts (from a moss, Plagiomnium affine) The Hill reaction is the light-driven transfer of electrons from water to Hill reagents (non-physiological oxidants) in a direction against the chemical potential gradient as part of photosynthesis. Robin Hill discovered the reaction in 1937.
In that study, a proposal for the rate at which A.ferrooxidans can oxidise pyrite is the ability to use ferrous iron to generate a ferric iron catalyst : Fe 2+ + 1 ⁄ 4 O 2 + H + → Fe 3+ + 1 ⁄ 2 H 2 O. Under the above acidic conditions, ferric iron (Fe 3+) is a more potent oxidant than oxygen, resulting in faster pyrite oxidation rates.
Pressure oxidation is a process for extracting gold from refractory ore. The most common refractory ores are pyrite and arsenopyrite , which are sulfide ores that trap the gold within them. Refractory ores require pre-treatment before the gold can be adequately extracted. [ 1 ]
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Diagenesis (/ ˌ d aɪ. ə ˈ dʒ ɛ n ə s ɪ s /) is the process of physical and chemical changes in sediments first caused by water-rock interactions, microbial activity, and compaction after their deposition. Increased pressure and temperature only start to play a role as sediments become buried much deeper in the Earth's crust. [1]