Colorado School of Mines Pressure Oxidation of Molybdenum ...

However, rhenium and molybdenum are soluble in an alkaline environment and can therefore be recovered selectively from a concentrate via an alkaline pressure oxidation system.

Extraction of Molybdenum and Rhenium from Concentrates by ...

Publication Date: 1973: Personal Author: Lindstrom, R. E.; Scheiner, B. J. Page Count: 16: Abstract: Electrooxidation techniques were investigated on a bench scale by the Bureau of Mines to determine applicability of the process for extracting molybdenum and rhenium from low-grade molybdenite concentrates.

Separation of rhenium and molybdenum from molybdenite ...

Molybdenum resources around the world are mainly associated with porphyry copper ores. Molybdenite (MoS2) is the main Mo mineral that has rhenium in its crystal lattice. This paper investigates the recovery of rhenium and molybdenum from a molybdenite concentrate using a hydrometallurgical treatment method. The molybdenite concentrate is …

Study of mechanisms involved in thermal migration of ...

XPS analysis allowed us to obtain the evolution of oxidation degree of rhenium and molybdenum at the very near surface (5 nm). Moreover, XANES studies gave us information on the structure of the compounds formed during annealing, the detection modes were chosen in order to probe either the whole implanted depth (150 nm) or only part of the implanted depth …

Molybdenite as a Rhenium Carrier: First Results of a ...

Molybdenite as a Rhenium Carrier: First Results of a Spectroscopic Approach Using Synchrotron Radiation . Teresa Pereira da Silva. 1*, Maria-Ondina Figueiredo. 1,2, Daniel de Oliveira. 1, João ...

How to Separate & Recover Molybdenum & Rhenium

Rhenium was stripped from the organic phase with a HClO4 solution and recovered by electrolytic deposition. This method was also used to extract molybdenum, but not to separate molybdenum from rhenium. Lee, Reynolds, and Bhappu studied the adsorption of molybdenum and rhenium on activated carbon.

Rhenium and Molybdenum complexes as catalysts in oxygen ...

In the past years, rhenium has - alongside with molybdenum - proven to be a suitable metal for the development of oxidation catalysts, especially rhenium in the oxidation state +VII and, to a much smaller extent, in the oxidation state +V. Mechanistic aspects of rhenium(V) systems are largely unexplored up to now.

Molecular Epoxidation Reactions Catalyzed by Rhenium ...

In this personal account, the development of rhenium, molybdenum, and iron complexes in molecular epoxidation catalysis is presented. Methyltrioxorhenium (MTO) is the benchmark catalyst for these reactions, with a thoroughly investigated mechanism and …

Roasting oxidation behaviors of ReS2 and MoS2 in powdery ...

The main oxidation methods for rhenium-bearing molybdenum concentrate are hydrometallurgy [16âˆ'22] and pyrometallurgy.

Refractory Metals & Alloys for Aerospace | Refractory ...

Refractory Metals & Alloys for Aerospace. Refractory metals refer to metals with melting points above 2000°C. They include tungsten, molybdenum, tantalum, niobium, rhenium, and vanadium. The common characteristics of refractory metals and their alloys are high melting point, high strength at high temperature, and good corrosion resistance to liquid metals.

Rhenium variations in molybdenite (MoS2): Evidence for ...

TY - JOUR. T1 - Rhenium variations in molybdenite (MoS2) T2 - Evidence for progressive subsurface oxidation. AU - Golden, Joshua. AU - McMillan, Melissa

US5437744A - Molybdenum-rhenium alloy - Google Patents

A molybdenum-rhenium alloy having an excellent low temperature ductility paired with an excellent high temperature strength. The alloy consists, essentially in % by weight, of 42 up to <45% Re, up to 3% each of W, Y, Rh, Sc, Si, Ta, Tb, V, Nb or Zr at which the sum of said elements is no greater than about 5%, the remainder being Mo besides normally present …

REGULATIONS OF OXIDATION OF RHENIUM HEPTASULPHIDE AT ...

REGULATIONS OF OXIDATION OF RHENIUM HEPTASULPHIDE AT RHENIUM CONCENTRATE PROCESSING Roman D. Allabergenov 1, Vitaliy P. Guro2, Sitorabonu N. Rasulova2, Edgor T. Safarov2, Khayitali F. Adinaev2 ...

Separation of rhenium from electric-oxidation leaching ...

The separation of rhenium from molybdenum in aqueous solution has always been a problem in hydrometallurgy. The separation of rhenium from the electro-oxidation leachate of molybdenite and its mechanism were investigated. The results show that pH of the leachate significantly affects adsorption rate compared with other experimental parameters. …

Refractory Metals: Niobium, Molybdenum and Rhenium ...

Alloys of molybdenum and rhenium are more ductile than pure molybdenum. An alloy with 35% Re can be rolled at room temperature to more than 95% reduction in thickness before cracking. For economic reasons, molybdenum-rhenium alloys are not widely used commercially. Alloys of molybdenum with 5 and 41% Re are used for thermocouple wires. Rhenium

US3770414A - Recovery of rhenium and molybdenum values ...

An improvement in the recovery of molybdenum and rhenium values by roasting molybdenite which comprises preheating finely divided molybdenite concentrate and passing it downwardly through a vertically oriented reaction zone countercurrent to an upwardly traveling stream of high temperature oxygen, oxygen enriched air or oxygen-sulfur dioxide mixture heated by its …

(PDF) Extractive Metallurgy of Rhenium: A Review

In nature, rhenium does not have its minerals, so it occurs in the form of isomorphic inclusions in copper and molybdenum ores, and is also present in smaller quantities in uranium deposits.

Kinetics of molybdenum--rhenium alloy oxidation (Journal ...

OSTI.GOV Journal Article: Kinetics of molybdenum--rhenium alloy oxidation. Kinetics of molybdenum--rhenium alloy oxidation (in Russian)

A Whiff of Oxygen Before the Great Oxidation Event?

Molybdenum and rhenium were probably supplied to Archean oceans by oxidative weathering of crustal sulfide minerals. These findings point to the presence of small amounts of O 2 in the environment more than 50 million years before the start of the Great Oxidation Event.

Molybdenum - Electron Configuration and Oxidation States - …

Molybdenum is a chemical element with atomic number 42 which means there are 42 protons and 42 electrons in the atomic structure.The chemical symbol for Molybdenum is Mo. Electron Configuration and Oxidation States of Molybdenum. Electron configuration of Molybdenum is [Kr] 4d5 5s1. Possible oxidation states are +6. Electron Configuration

The Refractory Noble Metals and Rhenium | Johnson Matthey ...

The effects of rhenium additions in improving the ductility of molybdenum and tungsten are ascribed to three factors. First, the rhenium is said to form with oxygen a complex molybdenum-rhenium oxide which does not, like MoO 2, give rise to a eutectic that wets the grain boundaries but tends to be redistributed within the alloy grains.Secondly, the rhenium promotes twinning …

Molecular Epoxidation Reactions Catalyzed by Rhenium ...

Request PDF | Molecular Epoxidation Reactions Catalyzed by Rhenium, Molybdenum, and Iron Complexes | Epoxidations are of high relevance in many organic syntheses, both in …

Molybdenum | Plansee

During the roasting process, this rhenium is sublimated as rhenium heptoxide (Re 2 O 7) and is retrieved in the dust separator as a by-product of the molybdenum preparation process. The roasted molybdenum concentrate, or molybdenum oxide as it is technically known, is sublimated at approximately 1000 °C or is cleansed even further using chemical methods.

High-valent oxo-molybdenum and oxo-rhenium complexes as ...

High-valent oxo-complexes have recently emerged as powerful catalysts for the activation of X–H (X = Si, B, P and H) bonds and for the reduction of several functional groups. This new reactivity represents a complete reversal from the traditional role of these complexes as oxidation catalysts and opened a ne

OXIDATION OF MOLYBDENUM, TUNGSTEN, AND RHENIUM …

Friedrich, K. OXIDATION OF MOLYBDENUM, TUNGSTEN, AND RHENIUM POWDERS AT ROOM TEMPERATURE AND IN AIR OF DIFFERENT HUMIDITY..Country unknown/Code not available: N. p., 1968. Web.

Clean separation and purification for strategic metals of ...

Molybdenum (Mo) and rhenium (Re) are strategic key metals for the development of modernization. In nature, 99 wt.% of Re is associated with molybdenite minerals via the form of isomorphism, and the element abundance of Mo (about 1.1–1.5 ppm) and Re (about 0.0004–0.0026 ppm) is tremendous in the continental crust.

Rhenium variations in molybdenite (MoS2): Evidence for ...

First, systematic increases in average and maximum trace concentrations of Re in molybdenite since 3.0 Ga point to enhanced oxidative weathering by subsurface fluids. In addition, episodic molybdenum mineralization correlates with five intervals of supercontinent assembly from ∼2.7 Ga (Kenorland) to 300 Ma (Pangaea). Highlights

The Kinetics of Oxidation of Molybdenite Concentrate by ...

M olybdenite (MoS 2) is the major mineral for molybdenum.In the conventional pyrometallurgical process, oxidation roasting is applied to produce MoO 3, one of the commercial products containing Mo.However, there are several serious problems in processing molybdenite by this method: Valuable elements in the concentrate such as rhenium and selenium cannot …

Properties and Compounds of Rhenium | Refractory Metals ...

Properties and Compounds of Rhenium. Rhenium is a silvery-white rare metal with a high melting point.I ts melting point ranks third among all elements, second only to tungsten and tantalum. Because metal rhenium is hard, wear-resistant, corrosion-resistant, and stable in air, it is widely used in aerospace, electronics, petrochemical, and other fields.

Refractory Metals: Niobium, Molybdenum and Rhenium ...

Molybdenum - Wikipedia

Molybdenum is a transition metal with an electronegativity of 2.16 on the Pauling scale. It does not visibly react with oxygen or water at room temperature. Weak oxidation of molybdenum starts at 300 °C (572 °F); bulk oxidation occurs at temperatures above 600 °C, resulting in molybdenum trioxide.

Recovery of Molybdenum & Rhenium From Molybdenite …

In the past years, rhenium has - alongside with molybdenum - proven to be a suitable metal for the development of oxidation catalysts, especially rhenium in the oxidation state +VII and, to a much smaller extent, in the oxidation state +V. Mechanistic aspects of rhenium (V) systems are largely unexplored up to now.

Rhenium Alloys - an overview | ScienceDirect Topics

Tungsten-rhenium alloys, applied by vapor deposition, are used to coat the surface of molybdenum targets in X-ray tube manufacture. Other rhenium alloys, with tungsten and molybdenum, are used for filaments, grid heaters, cathode cups, and ignitor wires in photoflash bulbs. One of the largest applications for rhenium is for mass spectrometer ...

Oxidation of thin molybdenum--rhenium foils (Journal ...

OSTI.GOV Journal Article: Oxidation of thin molybdenum--rhenium foils. Oxidation of thin molybdenum--rhenium foils. Full Record; Other Related Research; Authors: Witcomb, M J Publication Date: Sun Jun 01 00:00:00 EDT 1975 Research Org.: Univ. of the Witwatersrand, Johannesburg OSTI Identifier: 4184713

Electro-Oxidation of Molybdenum Concentrate Using Bipolar ...

Electro-Oxidation of Molybdenum Concentrate Using Bipolar Cell, and Recovery of Rhenium * by Tsembel DARJAA1, Toru H. OKABE2 Yoshio WASEDA3 and Yoshiaki UMETSU4 1 Introduction In a previous paper, the present authors have demonstrated

(PDF) Pressure Oxidation of Molybdenum Concentrates

During POX, the oxidation of molybdenum (Mo) is above 98%. More than 95% of the rhenium (Re) and 15% to 20% of the Mo are leached into solution. The sulfur in the concentrate is converted to H2SO4 ...