Questions tagged [metallurgy]

Chemical and physical characteristics of metals and alloys.

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30 views

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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2k views

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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2answers
98 views

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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53 views

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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1answer
144 views

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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2answers
824 views

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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464 views

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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1answer
64 views

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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1answer
84 views

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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146 views

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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1answer
82 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
51 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
79 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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290 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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97 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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37 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
49 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
368 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
94 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
175 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
78 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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207 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
48 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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42 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
541 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
37 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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104 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
223 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
130 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
862 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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106 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 ...
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1answer
48 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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124 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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314 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
50 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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24 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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61 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
534 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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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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81 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
971 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
83 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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752 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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3k 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
119 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
39 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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100 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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235 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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