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مرجع فرآوری مواد معدنی و هیدرومتالورژی
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MASS TRANSFER IN LEACHING OPERATIONS
send by:Mr M.Jafari
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MASS TRANSFER IN LEACHING OPERATIONS
(part2)
send by:Mr M.Jafari
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فلوشیت سیستم خردایش مدار بسته.
send by:Mr M.Jafari
@mineralprocessing
🔻Someday, when my ship comes in...
Someday, when I have the money....
Someday, when I have the time....
Someday, when I have the skill....
Someday, when I have the confidence....
یک روزی که کشتی من از راه برسد...
یک روزی که پولش را داشته باشم...
یک روزی که زمانش را داشته باشم...
یک روزی که مهارت و توانایی اش را داشته باشم...
یک روزی که اعتماد به نفسش را داشته باشم...

🔺How many of those statements have you said to yourself? Have I got some sobering news for you: "some day" doesn't exist, never has, and never will. There is no "some day". There's only today.
تا کنون چه تعداد از این جمله ها را به خودتان گفته اید؟ خبر مهمی برایتان دارم: "یک روزی" وجود خارجی ندارد. نه هرگز وجود داشته است و نه هرگز وجود خواهد داشت. هیچ "یک روزی" وجود ندارد. فقط امروز وجود دارد.


🔻When tomorrow comes, it will be another today; so will the next day. They all will. There is never anything but today.
وقتی که فردا از راه برسد، آن هم امروز دیگری خواهد بود؛ روز بعد از آن نیز همین طور. همه آنها این طور خواهند بود. هرگز چیزی جز امروز وجود ندارد.
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Scandium in a Nutshell: Is Scandium the next Industry Changing Metal?

Published on June 21, 2016

1. Scandium: What is it?

Scandium (Sc) is one of the elements that was predicted to exist by Dmitri Mendeleev, the 1860’s inventor of the periodic table of elements, before it was actually discovered in nature. Scandium was discovered by Lars Fredrik Nilson, a Swedish chemistry professor, in 1878 in the minerals euxenite and gadolinite, which had not yet been found anywhere except in Scandinavia.

In nature, it can be found in aluminum phosphate minerals, amphibole-Hornblende, basalt, beryl, biotite, cassiterite, columbite, gabbro, garnet, muscovite, pyroxene, wolframite and rare earth minerals such as bazzite, euxenite, gadolinite, ixiolite, kolbeckite, magbasite, perrierite and thortveitite. The main form of the Sc minerals and percentage of Scandium Oxide is presented in Table 1.

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Scandium is a soft, silvery metallic element with atomic number 21. While it is a transition metal (lightest of them), it sometimes is classified as a rare-earth element (REE’s) as it exhibits some rare earth element characteristics. While scandium is not particularly rare on the surface of the earth (31st most abundant and more abundant than lead, mercury and precious metals), it is very rare to find in concentrations over 100 ppm making commercially usable deposits very rare and generally it can be found in more than 100 minerals in trace amounts. Even when it is found at higher grade, processing can be complex, leading to very few stable sources of the metal.

Scandium typically exists in nature as its oxide form, scandium (III) oxide (ScO or scandia) which is the commonly traded form. Scandium was only isolated into its pure form in 1937, and the first full pound of pure scandium metal was produced in 1960.

The lack of any reliable supply of scandium has been the limiting factor in development of its application. However, should a dependable source of scandium become available, end-users would take the opportunity to use the material, and the metal would suddenly be in high demand.
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2. Scandium: Usage and Emerging Applications

Scandium is conventionally thought of as a scarce and expensive metal, with only a few niche applications such as military and space station. However most of scandium’s application to date has been driven availability (lack of reliable supply) and high prices. At the more reasonable price, scandium can be more widely adopted in the other application such as transportation and energy industries.

Scandium applications fall into three types of use:

To strengthen alloys of aluminum, either by itself or as an addition to existing multi-metal Al alloys in aerospace, aircraft, automotive, marine and rail industries:
Scandium is the most potent grain-refining agent known for aluminium (Al). Scandium additions of up to 0.5 percent can double or triple the tensile strength of certain aluminum alloys, while retaining the malleability of aluminum.
98% Al : 2% Sc super-alloys have the highest strength-to-weight ratio in use today.
Significantly improves strength, durability, plasticity, thermal conductivity and corrosion resistance.
Retain aluminium weldability without heat cracking and loss in strength (rivet-free aircraft).
Reduces overall weight and build-cost, improving fuel efficiency and aerodynamics.

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2. To employ certain outstanding electrical properties and heat resistance abilities in Solid Oxide Fuel Cells (SOFCs). Fuel cells were invented over a century ago and have been used in practically every NASA mission since the 1960’s, but until now, they have not gained widespread adoption because of their inherently high costs.

SOFCs convert a fuel source (typically natural gas CH) and oxygen into electricity, water, CO and heat. SOFCs use a hard ceramic material as a solid electrolyte between an anode and cathode, which when subjected to high temperatures, catalyses the conversion of natural gas to energy. Here is a typical arrangement of the anode, cathode and electrolyte.

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Lots of Patents replace Y in Yttrium Stabilized Zirconium electrolytes with Sc (SOFCs are devices that promote chemical reactions that oxidize a fuel source under high heat to generate electricity. They use a selective solid electrolyte to control the process, typically employing yttrium oxide to stabilize the material against heat. Substituting scandium for yttrium as the stabilizing agent improves the power density of the units (better conductivity).
Lower operating / reaction temperature that extends fuel cell life.
Critical for fuel cell dynamics, economics (cuts the cost) and environment (through generating less CO2).
3. To capture unique optical properties including natural lighting effects in lamps (as Scandium iodide- ScI), improvements in lasers and crystals, and video screens such as TV studios, cinema/photography and stadium lighting systems. Certain lasers employ gadolinium scandium gallium garnets, and scandium is used in select high performance switches in computers.

Scandium combusting on the sun is what gives us ‘sunlight’. Scandium produces a natural light in a lighting element, very much like natural sunlight to the human eye.
Widespread use in film set and stadium lighting to replicate daylight.
New environmentally benign incandescent replacement.
There are also some emerging industries which can grow the scandium usage as:

High voltage tension wire – high efficiency transmission lines due to Sc-Al alloys having high electrical conductivity.
Sporting equipment – baseball bats, golf clubs, lacrosse sticks, bicycle frames.
High intensity lamps – scandium-based lamps provide light which most resembles sunlight.
3. Scandium: Supply and Demand

The first reported large-scale scandium production was associated with Russian military programs. Not much details are available but Russians alloyed the metal with aluminum to make lightweight MIG fighter parts. Mining at these historic Russian production sites has ceased. There was only one reported scandium producer from primary deposit in Ukraine (Zhovti/Vodi mine, it appears the mine was flooded some years ago and has not produced any scandium since then).

The rest of the Scandium metal is produced as a by-product of processing activities associated with the production of other metals, minerals (Uranium ore, Bayer processing to produce Alumina and some Nickel laterite ores) or rare earths. The current main producing countries that supplying Scandium in form of oxide or metal as by product are China (Bayan Obo rear earth mine) and on Russia (apatite mines on Russia’s Kola Peninsula and by product of Alumina production). There were countries with past producing record that include Kazakhstan (by product of uranium mining), Norway and Madagascar (both by product of processing pegmatite).

The fact is demand is there, supply is lacking:

Global Scandium trading / production is small; almost 10 tons per annum (tpa) sourced primarily as a by-product from China (REEs), Russia (from Bauxite residue – Red Mud), Ukraine (the only world direct deposit), Kazakhstan (as Uranium ore residue/by product).
Neither the US Department of Commerce nor the International Trade Commission has specific data on trading for Scandium metal.
There is no formal buy/sell market, Scandium is not traded on an exchange and there are no terminal or futures markets.
Scandium metal is traded between private parties, mostly at undisclosed prices and in undisclosed amounts.
Aerospace and SOFCs industries (e.g. Bloom Energy) would like to see stable supply of 300 tpa of Sc production before retooling.
Companies mining rare earth elements rarely disclose their scandium production, making it difficult to estimate the global scandium production with any accuracy.
Some suppliers of scandium metal and scandium compounds include: Absco Materials; Alfa Aesar (part of Johnson Matthey); Atlantic Equipment Engineers (part of Micron Metals); GFS Chemicals; Goodfellow (part of the Goodfellow Group); Materion (formerly Brush); Stanford Materials, and The Low Hanging Fruit Co. BV.
4. Scandium: Risks