3 edition of Pyrrhotite oxidation and coating as a means of passivating oxidation found in the catalog.
Pyrrhotite oxidation and coating as a means of passivating oxidation
|Series||Canadian theses = Thèses canadiennes|
|The Physical Object|
|Pagination||xiv, 104 l. :|
|Number of Pages||104|
Experimental Study of Pyrite Oxidation at pH and 30°C by Martin B. Goldhaber Abstract Experimental studies of pyrite oxidation over the pH range were carried out at 30°C in M KC1 under conditions of fixed pH and p Rate of addition of base necessary to maintain a fixed pH was monitored. SamplesCited by: 4. Black Oxide, blackening, oxidizing, oxiding, black passivating, gun bluing these terms all refer to the process of forming a black iron oxide on the surface of ferrous metals. The black oxide process is a chemical conversion coating. This means that the black oxide is not deposited on the surface of the substrate like nickel or zinc.
Geophysical techniques, spectral induced polarization (SIP) in particular, may provide a means of such performed laboratory experiments to assess the sensitivity of the SIP method to the oxidation mechanisms of common sulfideminerals found in mine waste deposits, i.e., pyrite and pyrrhotite, when the primary oxidant agent is. The key difference between electropolishing and passivation is that electropolishing gives a superior finish and removes discolouration that passivation would leave behind.. Electropolishing is an electrochemical process that removes material from a metallic surface in order to reduce surface roughness while passivation is the process of coating a .
minerals; and that the oxidation/ alteration of pentlandite is substantially slower than pyrrhotite, although both minerals are effectively covered with a very thin overlayer of FeOOH after 30 minutes in pH solution. This paper expands the scope of our oxidation/alteration studies of pentlandite and pyrrhotite by investigating the ef-. Welcome to the world's most popular metal finishing website 1. Forums. Whether painting, plating, powder coating, PVD, anodizing, bluing, galvanizing, or any finish, this forum connects the luminaries of the finishing world for camaraderie, while offering students & hobbyists a chance to get their questions answered or share their tips.
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Oxidation rate of pyrrhotite is faster than that of pyrite due to the vacancy of iron atoms in the pyrrhotite crystal structure (Belzile et al., ). Thus DO shortage was much more in the Pyrr. Encapsulation is based on the inhibition of O 2 diffusion by a surface coating agent and is expected to control the oxidation of pyrite, pyrrhotite, and chalcopyrite for a substantial period of.
Pyrrhotite Coating to Prevent Oxidation Author: Zoe J. Georgopoulou, Kostas Fytas, Heriban Soto, Bill Evangelou Subject: Tailings, Waste Rock & Slag Management Keywords: acid mine drainage, iron phosphate coating, pyrrhotite oxidation Created Date: 7/13/ PM. Abstract.
Pyrite and other iron sulfides are readily oxidized by dissolved oxygen in aqueous phase, producing acidity and Fe 2+, which causes significant environmental ations of surface coating agents (Na 2 SiO 3 and KH 2 PO 4) were conducted at Boeun (Chungbuk, South Korea) outcrop site, and their efficiencies to inhibit the oxidation of Cited by: LABORATORY STUDIES OF PYRRHOTITE OXIDATION MEND Project This work was done on behalf of MEND and sponsored by INCO Limited, Noranda Inc., the Ontario Ministry of Northern Development and Mines and the Canada Centre for Mineral and Energy Technology (CANMET) through the CANADA/Northern Ontario Development Agreement (NODA) March File Size: 1MB.
a new representation is proposed for the pyrrhotite oxidation process. Both observations denote a signif - icant contribution towards the development of more realistic models to predict the evolution of the ISA. BACKGROUND ON PYRRHOTITE OXIDATION. The oxidation process of pyrrhotite may be caused either by the activity of microorganisms or.
ANALYSIS OF THE OXIDATION OF CHALCOPYRITE, CHALCOCITE, GALENA, PYRRHOTITE, MARCASITE, AND ARSENOPYRITE By G. Reimers1 and K. Hjelmstad2 ABSTRACT Conditions in the underground mine environment can cause self-heating of sulfide ores as a result of exothermic oxidation reactions, which may result in mine by: 4.
Aqueous oxidation of pyrite by molecular oxygenCited by: The Pyrrhotite oxidation and coating as a means of passivating oxidation book of surface oxidation of pyrite and pyrrhotite have been determined from analysis of linear potential sweep voltammograms.
Pyrite oxidizes to both sulphur and sulphate. The formation of sulphur is restricted to the order of a monolayer at pH but significant yield occurs at pH Cited by: Laboratory SIP signatures associated with oxidation of disseminated metal sulfides.
precipitation of secondary minerals and the formation of a passivating layer to oxidation coating the mineral surface may also contribute to these increases.
the overall oxidation reaction of pyrrhotite promoted by O 2 proceeds as follows Cited by: Evolution of pyrrhotite oxidation in aggregates for concrete Rocks containing pyrrhotite bands are sometimes used to produce concrete. These rocks oxidize and produce long-term expansive reactions that damage concrete structures, leading to.
pyrite oxidation decay is to store specimens within a moisture and oxygen barrier containing an oxygen scavenger. Further oxidation can be reduced or. eliminated by storing specimens in an environment with a humidity level below 30%. Ammonium gas and ethanolamine thioglycollate treatments neutralize.
Acid mine drainage (AMD) occurs when sulfide minerals are exposed to an oxidizing environment. Most of the methods for preventing AMD are either short-term or high cost solutions. Coating with iron phosphate is a new technology for the abatement of AMD.
It involves treating the sulfide with a coating solution composed of H2O2, KH2PO4, and sodium acetate Cited by: A series of thermodynamic calculations are performed for the roasting of pyrite in changing temperatures and atmospheres.
The relationship between ΔrGθ and temperature in the range of T = – K shows that, depending on the atmosphere it is in, reactions of pyrolysis, oxidation or reduction can occur. Both the pyrolysis of pyrite in an inert atmosphere and its oxidation by Cited by: 1. The influence of conditioning on the flotation of pyrrhotite in the presence of chlorite was investigated through flotation tests, sedimentation tests, and X-ray photoelectron spectroscopy (XPS) analysis.
The flotation results show that chlorite slimes dramatically impair the flotation of pyrrhotite. Sedimentation and flotation tests reveal that conditioning can effectively remove Cited by: 6. - Laboratory studies of pyrrhotite oxidation - Ma Pyrite and pyrrhotite are the most abundant sulphides in mine wastes worldwide.
While there is a large body of information related to the weathering of pyrite and the effects of this process on water quality, there is a significant deficiency of information on the. Passivation, in physical chemistry and engineering, refers to a material becoming "passive," that is, less affected or corroded by the environment of future use.
Passivation involves creation of an outer layer of shield material that is applied as a microcoating, created by chemical reaction with the base material, or allowed to build from spontaneous oxidation in the air.
Oxidation of metal sulfide minerals is responsible for the generation of acidic waters rich in sulfate and metals. When associated with the oxidation of sulfide ore mine waste deposits the resulting pore water is called acid mine drainage (AMD); AMD is a known environmental problem that affects surface and ground waters.
Characterization of oxidation Cited by: A simple mathematical model was formulated to explain the leaching and passivation of chalcopyrite at low temperature (°C).
The reaction kinetics can be explained in terms of a mixed diffusion/chemical reaction model where the reaction rate is initially dependent on the rate at which copper and iron diffuse through the thickening passive by: 3. As described before, the concentration of the alloying elements of the coating decreases with increasing oxidation time.
Both samples have endured the oxidation without damage, but a sample oxidized at K failed. The W–Si–Cr layer was partly delaminated from the substrate during the oxidation by:. Pyrrhotite Oxidation (9 replies) (unknown) 4 years ago (unknown) 4 years ago. I need to know what chemical reaction takes place when pyrrhotite is heated in presence of air.
It is evident that Fe3O4 and SO2 will be produced but unable to figure out the exact equation. (unknown).These transient increases appear to correlate with increases of soluble oxidizing products, e.g., Fe(2+) and Fe(3+) in solution; precipitation of secondary minerals and the formation of a passivating layer to oxidation coating the mineral surface .We examined the sensitivity of the electrochemical spectral induced polarization (SIP) model developed by Wong to the oxidation extent of pyrite and pyrrhotite minerals disseminated in silica sand.
to assess the oxidation state of sulfides and also to infer the formation of passivating layers coating the metal minerals during oxidation Cited by: