Questions tagged [metallurgy]

Chemical and physical characteristics of metals and alloys.

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Voltage required for electrolysis of molten Cu2O feedstock

Would someone mind clarifying the overpotential voltage required for molten Cu2O. Looking at Redox charts all Oxygen reactions use hydrogen or other atoms or molecules. The goal is to calculate the ...
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What is the reason for extracting copper from copper pyrites and not iron?

Why can copper be extracted from copper pyrites ($\ce{CuFeS2}$) but not iron? Is there some intuitive logic behind it?
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Material selection based on minimum contact area and maximum bearing load

I need to find a good material to manufacture japanese knives' blades with Granta Edupack (former CES). I found a very usefull source about material selection in mechanical design which claims I have ...
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Gold cyanidation process

My chemistry book says the following: In the metallurgy of silver and gold , the respective metal is leached with a dilute solution of $\ce{NaCN}$ in presence of $\ce{O2}$ as a result of which the ...
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Can a plain sheet of stainless steel adhering to the 316 grade be regarded as food safe at every finish level?

My question is not purely about chemistry but it definitely involves it. I was looking for a while to buy a food-grade stainless steel plate that would fit my home pizza gas oven (to have the dough ...
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Ellingham diagram/graph for tungsten

I've recently come across one of the methods to form tungsten carbide($\ce{WC}$) from wolframite ($\ce{(Fe,Mn)WO4}$) by using carbothermic reduction which was supposedly one of the first methods for ...
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Aluminum Alloy with most alkaline resistance [closed]

Previously i asked this question in Engineering SE: What aluminum grade is the most resistant to corrosion in alkaline environment? Some input from others seem indicating that no mass-produced ...
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How to determine the visual properties of a specific steel compound?

The material that is described in a paper by Li et. al.[1] is interesting to me, but they don't go into any details on what the end result would look like visually. Out of curiosity, I was wondering ...
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How to Improve Phosphoric Acid 85% leaching of Natural Titanium Rutile without increasing impurity?

Using magnetically separated natural titanium rutile from a mine in South Africa to leach titanium for oxide production using H3PO4 85%. (The reason for using H3PO4, is that it separates out any Fe ...
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Dehydrating hydrated Magnesium chloride

I came to know that hydrated Magnesium chloride $\ce{MgCl6.6H2O}$ is dehydrated not directly by heating as it gets hydrolysed to $\ce{MgO}$ . But instead it is dehydrated by passing through $\ce{HCl}$ ...
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The role of 2-nitrophenol in tin etchant (aqueous mixture of 2-nitrophenol and NaOH)

Aqueous mixture of 2-nitrophenol and NaOH is a time-honored etchant that dissolves tin-rich alloy and retain the intermetallic compounds from the tin. I wonder the role of 2-nitrophenol in the etching ...
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How can steel be so different from iron, even if amount of carbon is small?

Perhaps I am too naive, but I am having a hard time visualizing how even 'high-carbon' iron and steel alloys are maybe, at most, about four percent carbon by mass, which still means only one (smaller) ...
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Natural preservatives of ink

Would pure compounds like thymol, carvacrol and cinnamaldehyde work as preservatives of fountain pen ink? I'm specifically interested in three properties - Prevention of growth (mostly fungal) in the ...
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Extraction of copper from chalcopyrite

During the extraction of copper from chalcopyrite ore, the ore ($\ce{Cu2S.Fe2S3}$) is heated to form $\ce{Cu2S}$ and $\ce{FeS}$. Then during smelting it reacts with $\ce{O2}$ to form $\ce{Cu2O}$. Then ...
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Why do mineral particles become wet by oils while the gangue particles by water?

In my textbook, NCERT Chemistry for class 12, it is mentioned that one of the principle of froth floatation method is the following: The mineral particles become wet by oils while the gangue ...
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Why is the term "nascent nitrogen" still used in metallurgical industries?

Continuation of Why do nitrogen-containing organic compounds give N2 as the combustion product? (comment converted into question) Nascent state is an obsolete theory in chemistry and is discredited. ...
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How to separate Cu and Ni from alloy containing different metals such as Al, Cu, Ni, (Zn, Pb, Sn < 5%)?

I have an alloy containing different metals such as Al, Cu, Ni, (Zn, Pb, Sn, Ag, Si in small amount < 5%). How can I separate Cu and Ni from this alloy? I tried to dissolve alloy in sulfuric acid, ...
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Why is the only natural source of radium compounds uranium minerals?

A common mineral of barium is barytes, or barium sulfate ($\ce{BaSO4}$). Because elements in the same periodic group have similar chemical properties, we might expect to and some radium sulfate ($\...
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What is the alloying composition of the Zinc-Platinum System?

My research team and I are working on a bimetallic alloy consisting of Zinc and Platinum. We have looked for papers regarding the composition of Zinc-Platinum alloy. But there aren't many papers out ...
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Why same metal salt is required in electrolytic refining?

Why we use same metal salt in electrolytic refining? Ex. For $\ce{Cu^2+}$ if we take suppose $\ce{FeSO4}$ so there are 2 ions ready to react on cathode ie $\ce{Fe^2+}$ and $\ce{Cu^2+}$. But from a ...
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Why is the formation free energy of carbon dioxide almost constant in Ellingham diagrams?

While reading about Ellingham diagram in my textbook, I noticed that for: $\ce{C_(_s_) + O2_(_g_) -> CO2_(_g_)}$, the standard Gibbs free energy ($\ce{\Delta_fG^\circ}$) doesn't seem to vary with ...
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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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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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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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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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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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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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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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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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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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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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1 answer
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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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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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2 answers
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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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1 answer
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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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1 vote
1 answer
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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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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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1 answer
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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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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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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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3 votes
1 answer
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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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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 ...
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4 votes
1 answer
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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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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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3 votes
2 answers
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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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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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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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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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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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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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