Search results
Results from the WOW.Com Content Network
The pyrite is stable until exposed to air, at which point the pyrite rapidly oxidises and produces sulfuric acid. The impacts of acid sulfate soil leachate may persist over a long time, and/or peak seasonally (after dry periods with the first rains).
The chemistry of oxidation of pyrites, the production of ferrous ions and subsequently ferric ions, is very complex, and this complexity has considerably inhibited the design of effective treatment options. [6] Although a host of chemical processes contribute to acid mine drainage, pyrite oxidation is by far the greatest contributor.
The strong acidification of the medium caused by pyrite oxidation releases bicarbonate ions (HCO − 3) or carbon dioxide (CO 2) along with calcium (Ca 2+) and sulfate ions (SO 2− 4). Full pyrite oxidation can be schematized as: 2 FeS 2 + 7.5 O 2 + 4 H 2 O → Fe 2 O 3 + 4 H 2 SO 4. The sulfuric acid released by pyrite oxidation then reacts ...
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.
The formation of goethite is marked by the oxidation state change of Fe 2+ (ferrous) to Fe 3+ (ferric), which allows for goethite to exist at surface conditions. Because of this oxidation state change, goethite is commonly seen as a pseudomorph. As iron-bearing minerals are brought to the zone of oxidation within the soil, the iron turns from ...
The soil and groundwater are tested both before and after oxidant application to verify the effectiveness of the process. Monitoring of gases given off during oxidation can also help determine if contaminants are being destroyed. Elevated levels of CO 2 is an indicator of oxidation. [citation needed]
Jarosite is a basic hydrous sulfate of potassium and ferric iron (Fe-III) with a chemical formula of KFe 3 (SO 4) 2 (OH) 6.This sulfate mineral is formed in ore deposits by the oxidation of iron sulfides.
In soil science, mineralization is the decomposition (i.e., oxidation) of the chemical compounds in organic matter, by which the nutrients in those compounds are released in soluble inorganic forms that may be available to plants. [1] [2] Mineralization is the opposite of immobilization.