Questions tagged [metallurgy]

Chemical and physical characteristics of metals and alloys.

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1answer
45 views

Why are calcination and roasting processes carried out at a temperature just below the ore's fusion temperature?

I had read about the two important methods used for the concentration of an ore - Roasting and Calcination. I have a doubt regarding why both the methods are carried out at temperatures not above the ...
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1answer
35 views

How thick is the colored oxide layer on heat treated stainless steel? [closed]

When stainless steel is welded, or just heat treated, it will develop a thicker oxide layer, which in some cases is is rainbow colored, but can become so thick as to appear almost black. From the ...
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1answer
72 views

Why does Cody use Litharge? [closed]

In many of the precious metal refining videos Cody (Cody's Lab) takes the sample with the precious metal and puts Litharge into it. After heating it in the furnace, while pouring it out the molten ...
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1answer
184 views

Why are rare earth metals and platinum group metals are often found clustered together in ores

Rare earth and platinum group metals are often found clustered together in the earth's crust. Mining for platinum, for instance, also yields Rhodium and Ruthenium belonging to the same group. Likewise,...
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15 views

Gold CIL/CIP Leach Circuit

Could anyone explain why the adsorption tanks are being fed twice, with one input from the top of the tank (Strong and weak slurry), while also another input from the bottom (Fresh Carbon). Why does ...
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1answer
57 views

Roasting of galena

In the metallurgy of $\ce{Pb}$, Galena is first concentrated by froth floatation process. It is then partially roasted to and self reduced to obtain $\ce{Pb}$. Why is galena only partially roasted(...
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34 views

Calculating change in Gibbs Free Energy for a specific type of problem

Can anyone describe what is going on here? $$Si(liq.)=Si_{(1 weight percentFe)}$$ I have come across this statement quite a few times in Metallurgical Thermodynamics.All that they ask for is change in ...
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1answer
44 views

Properties of inconel [closed]

I am doing a project on the physics of the spaceX raptor engine. I believe it is made out of a certain type of inconel alloy. I want to understand why this alloy has the properties that it does, but I ...
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2answers
335 views

How to refine manganese metal from manganese(IV) oxide found in batteries? [closed]

I opened up some lantern batteries, and inside there's $\ce{MnO2}$ powder, carbon rods, and zinc casings, and other stuff that I don't know what it is exactly. I scraped out $\ce{MnO2}$-containing ...
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1answer
81 views

Thinking of reducing aluminum hydroxide with magnesium

Is it possible to reduce aluminum hydroxide to aluminum metal by using a sacrificial magnesium electrode in a single displacement reaction? I checked my revision of redox charts and it looks like it ...
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1answer
119 views

Origin of the 15% difference limit between solute and solvent atom radii in the Hume-Rothery rules

According to the Hume-Rothery rules for the substitutional solid solutions the atomic sizes of the the solute and solvent must not differ by more than 15%. Why should it be so?
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1answer
61 views

Are there any sulfides, sulfates, carbonates that cannot be dissolved by aqua regia? [closed]

I was looking into these specific minerals: arsenopyrite, pyrite, chalcopyrite, barite, calcite, dolomite. I investigate issues with tellurides not showing expected gold concentrations.
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70 views

Are Alloy Compositions Given in Weight Percent or Atom Percent

Often times I see alloys described like this, Lockalloy is an alloy that consists of 62% beryllium and 38% aluminum Are the precentages mentioned here in weight percent or atom percent? Is there a ...
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2answers
42 views

Thermal properties of aluminium alloy 6063 [closed]

I am looking for the operating temperature range both in a cold and hot environments (minimum and maximum operating temperatures) for aluminium alloy 6063. I'm new to finding this kind of information ...
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1answer
33 views

Can a metal which contains impurity of another metal that is more reactive than itself be electrorefined?

So I know that cathode is made of pure metal and anode of impure. For example take Cu. Cu will be oxidised to Cu+2 at anode and will deposit at cathode. But now if it contains impurity of , let's say, ...
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1answer
189 views

What's the difference between Zinc Ascorbate and Zinc Gluconate?

I've been looking at a dental product for pets, called MAXI/GUARD Oral Cleansing Gel and it states it uses zinc ascorbate/taurine, however in the ingredients I found elsewhere it instead lists zinc ...
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1answer
35 views

Manufacture an artifact with compression

Room-temperature superconductivity has finally been demonstrated, as reported by Quanta (and others), with the caveat that it requires compression of the substrate at nearly 2 Mbar. Obviously, this ...
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1answer
57 views

Why is there carbon lining on the steel vessel in Hall Heroults process?

I read This answer, and completely understand that why graphite anode is used , but I have read that the vessel acts as the steel cathode but with lining of carbon. What is the need of this carbon ...
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1answer
130 views

What explains the case hardening color effect?

Year 11 chemistry student here. I'm curious about how the case hardening effect works on metals. I know that when the electrons gain an energy 'level' or lose an energy 'level' they emit light at ...
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2answers
101 views

What lab equipment did Marie Curie use to isolate radium?

My experience in growing crystals for condensed matter physics has been sealing grams of material in ampoules which get heated in laboratory furnaces, so I don't have the experience to understand how ...
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1answer
450 views

How does liquid gallium interact with a gold leaf

I would like to know what happens when gold leaf comes into contact with liquid gallium. Will the gold dissolve into (alloy with) the gallium, wet the gallium or have no reaction with gallium? The ...
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70 views

What is the minimum thickness for stainless steel crucible to melt aluminum

I am planning to make a stainless steel crucible (air-tight) to melt aluminum. Aluminum is known to oxidize in presence of air. I therefore want to create a custom crucible made with sheet metal ...
4
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1answer
45 views

Home foundry — melting aluminum, mitigating undesirables

I am going to be melting aluminum cylinder head and some soda cans in the home foundry. I am aware the sulphur and the hydrogen present in the melt can make aluminum prone to cracks and brittle. Are ...
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80 views

Is melting aluminium in the presence of carbon dioxide desirable?

So aluminium cans melting is prone to formation of aluminium oxide due to presence of oxgygen and thin sheet of aluminium (large surface area). To mitigate this I can design a cruicible which is ...
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2answers
259 views

Why does an mercury ore exist as HgS?

Cinnabar($\ce{HgS}$) is one of the most common ores of mercury. Why does it not exist at $\ce{HgO}$ or some other such compound? Is there any reason for why it is so prevalent? Does it react less ...
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1answer
41 views

Side product obtained in reduction of cuprous oxide with carbon

So my book sates that in the extraction of cuprous oxide, the following reaction takes place. $$\ce{Cu2O + C -> 2 Cu + CO}$$ This makes sense to me, if it is seen as the following two reactions ...
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22 views

Can metal matrix composites be alloyed after their creation?

I've done a little research on metal matrix composites (MMCs), purely for fun and out of interest. Different types of metal powders are combined with reinforcement materials, to produce a reinforced ...
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50 views

Why does 'softening' of lead oxidise only elements other than lead?

In a flowchart describing the steps to refine lead obtained after the reduction step, my book1 gives a short note on the process 'Softening of lead' where the crude lead is melted in the presence of ...
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1answer
100 views

How many kilograms of graphite are consumed while producing 4 kg of Al through Hall-Heroult process?

How many kilograms of graphite are consumed while producing 4 kg of $\ce{Al}$ through Hall-Heroult process? This looks like a simple stoichiometry problem: $$\ce{4Al^3+ + 12e- -> 4Al} \; \; \; \; \...
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27 views

How can a minor constituent of an alloy, like carbon in steel have such a profound effect? [closed]

In steel that is 0.65% carbon by weight, barely one in 34 atoms is carbon (assuming no other additives/impurities). How can such an outnumbered constituent make such a big difference? Surely many of ...
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66 views

Are platinum metal whiskers very unusual?

Over 20 years ago I pulled my first set of platinum spark plugs out of a car because the engine was missing badly. Two of the six plugs each had one whisker in the gap between electrodes. One crossed ...
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1answer
621 views

Electrolytic Refining of Silver Nitrate

I read that the electrolytic refining of Silver is done using dilute silver nitrate as an electrolyte and a small percentage of free $\ce{HNO3}$. The following reactions are possible at the anode: $$\...
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1answer
77 views

What is the naming convention for Sn and Pb in inter-metallic compounds?

How would one go about naming inter-metallic (specifically, transition post-transition) compounds containing tin and lead? It is usually easy figuring out the naming of such compounds as they follow ...
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2answers
455 views

Why is Na+ reduced instead of H+ in the electrolysis of dilute NaCl(aq) with Mercury cathode?

In a class of electrolysis, my instructor told me that Hg forms Na-Hg in the electrolysis of dilute NaCl aqueous solution. For this reason, sodium cations are reduced in the cathode instead of ...
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2answers
1k views

Fumes by Melting Aluminium Soda Cans [closed]

I am planning to melt and cast aluminium from soda cans. I went to quora page that deals with "burning" aluminium can, which can release toxic gases as the cans are coated with plastic inner lining. ...
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1answer
99 views

What makes metals malleable and ductile? [closed]

Two well-known Physical Properties of metals is that they are malleable and dutile I was just wondering about what causes metals to be malleable and/or ductile and non-metals to be brittle? What ...
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1answer
30 views

Reactions of Depressants

In the froth flotation process, the concentration of a sulphide ore takes place using $\ce{NaCN/KCN}$ as a depressant. It forms a soluble complex with the impurity sulphide. Taking the particular ...
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69 views

Difference between calcination, roasting and pyrolysis

Hie everyone. I have been going through pyrometallurgical processes for recycling lithium-ion batteries and l have been coming across these terms; calcination, pyrolysis and roasting which l need ...
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186 views

Why does copper oxidise if it is considered a “noble metal”?

I'm an electrical engineer and not a chemist, so please excuse me if this is obvious. When soft-soldering electronic parts, we’re normally taught to clean copper of oxides (like using flux and so on) ...
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3answers
9k views

Why isn't the American nickel magnetic?

I never thought that modern American nickels actually contained nickel anymore. However, according to this wiki article, the coins actually do contain 25% nickel, the rest being copper. And yet, no US ...
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50 views

Importance of concentration of gold in gold parting

I read following lines about gold parting: Gold is not attacked by $\ce{H2SO4}$ or $\ce{HNO3}$, but copper and silver dissolve in them, when concentration of gold is less than $30\%$. If however, ...
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1answer
126 views

Use of Spiegeleisen in manufacture of steel

I recently read the following statements related to Manufacture of steel via Bessemer Process: When no more $\ce{CO}$ is produced (i.e. blue flame disappears) a calculated amount of Spiegeleisen (...
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1answer
40 views

Could metal hydride storage tanks for hydrogen store helium as well, given their repective atomic radii? [closed]

With atomic radii very similar, could helium dissolve into metallic foam about as well as hydrogen, thus making metal hydrite hydrogen tanks suitable for helium as well?
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98 views

In pig iron, from where does carbon in it comes from?

I've read that: "During extraction of iron another impurity appear which is carbon from coke in furnace." However, I don't understand how there will be enough unreacted carbon that would blend ...
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1answer
79 views

Should I be concerned about a galvanic reaction between silver solder and stainless steel?

I would like to solder a drain fitting onto my ultrasonic cleaner's tank. The fitting and the tank are both stainless steel. During its operation, the tank is filled with a cleaning solution and heat ...
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2answers
751 views

What does it mean to 'fuse' ores and why do we use alkali metals in the process?

For the extraction of chromium, fusion of chromite ore with sodium or potassium carbonate in excess of air is done. What exactly happens in this 'fusion' process? According to my textbook (class XII ...
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3answers
766 views

What is Rinman's green used for? [closed]

I can't find any info about it's uses neither in book nor in internet. Any help would be appreciated.
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3answers
193 views

How can Ellingham diagrams be linked to Gibbs energies of formation?

My textbook1 quotes the following as the limitation of Ellingham diagram: The interpretation of $\Delta G_\mathrm{f}^\circ$(standard Gibbs free energy of formation) is based on $K$ ($\Delta G_\...
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1answer
35 views

Difference between a species and a phase in a solution? [closed]

Overview: As of my knowledge from metallurgical thermodynamics a phase is a thermodynamically stable and homogeneous entity made up of different species of a given concentration. e.g = 'Austenite' ...
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23 views

Zinc Ink Availability [closed]

does anyone know where I could purchase zinc ink? Sigma Aldrich only sell Zinc Oxide, and I'm struggling to find a method in which I could remove the oxide after I print onto a polymer substrate. ...

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