Talk:Crystallization

crystallization process principle and operation

Crystallization is more than just a wet chemistry technique. You or I should look through Special:Whatlinkshere/Crystallization Processes for the topics of interest, and expand the article into something more comprehensive.--Joel 18:07, 10 October 2005 (UTC)

_ _ Second that, and add crystallization in nature. I've writ what i can without getting beyond my depth into crystalization of plutonic magma to form cubic-faced trap rock.
--Jerzy•t 08:00, 18 December 2005 (UTC)

Revision of the article

I might translate the article on crystallization I made for it.wiki, if this is of interest- in case, let me know here. I would need a colleague chemical engineer to revise my English, probably good but not perfect. UbUb 20:29, 4 April 2006 (UTC)

Done. The new article is crystallizer.--UbUb 19:12, 24 June 2006 (UTC)

Merging Crystallization and Crystallizer

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section.

I am not a user of en.wiki, so you may probably know better. But merging the articles is tantamount to merging car with engine.--UbUb 06:15, 27 June 2006 (UTC)

I'd say no to merging currently. This short article has a focus on crystal chemistry in nature (mineralogy, petrology, meteorology ...) whereas the newly translated (good work UbUb!) crystallizer article focuses on chemical engineering applications. I think there is sufficient info available to significantly expand this article and keep that article with its current focus. --Vsmith 12:13, 27 June 2006 (UTC)

I vote to "not merge". They treat different subjects (physics and engineering) and are for different publiques ("Crystallizer" is more technical). -- Krauss 29 July 2006 (UTC).

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Proposed merge of Recrystallization (chemistry) and Crystal growth

There a quite a few articles on aspects of crystals and Crystallization. I wonder to what degree some of these articles could be merged. For example, It seems that crystal growth is quite closely related to Crystallization (engineering aspects) Crystallization (if not the same) and Recrystallization_(chemistry).

See also:

Crystallization

Crystal growth

Recrystallization

Crystal

Crystal structure

Crystallite

Fractional crystallization

Seed crystal

Single crystal

and articles cited therein also!

I suspect it would take a brave person to try and untangle/merge these articles !! -- Quantockgoblin 13:43, 23 January 2007 (UTC)

Updated above to propose merger of only three of the most closely related articles, particularly the first two. -- Quantockgoblin (talk) 19:48, 5 October 2009 (UTC)

I'm no expert on the topics, so take anything I say with a grain of salt. The article titles and topics seem very closely related, but just glancing through each of them, they currently seem like well established articles that might be difficult to merge. I could be mistaken because of possible overlap. Wizard191 (talk) 20:50, 5 October 2009 (UTC)

Technically, all these terms and phenomena (Recrystallization (chemistry), Crystal growth and Crystallization) are rather different. The articles do not fully cover the topics defined by their names, but they are quite different and reasonably developed. I am a specialist in this area and like merging articles, but I would pass here and would not recommend others to merge. I would try to develop (fix) the articles individually and then see what happens - actually long hoping to do that, just can't find time. Materialscientist (talk) 04:22, 7 October 2009 (UTC)

Materialscientist, thanks for your input. I am a chemist, and familiar with the subject matter in general. However, I'm not sure I would claim to be an expert, but then again, I'm not sure what the threshold for "expert" in this field is?! Also given the controversy about experts in the past on Wikipedia, perhaps we should stick to the facts (PS - I’m sure you are an expert and not offence is intended). In this regard perhaps you can help clarify a few points for me:

• Isn’t crystal growth just the physical (stepwise) process by which crystalization occurs, in much the same way that “laying bricks” is the stepwise process by which “bricklaying” occurs?
• Isn't recrystallization (chemistry), simply the same process as crystalization, but simply repeated, normally for the purpose of obtaining purer crystals?

  Not always. Consider crystal growth as "laying bricks". Those "bricks" come from anywhere, move around freely (in the gas or liquid), and stick to certain sites on a substrate or a seed to grow a crystal. Recrystallization often means a crystal has been amorphized, or made polycrystalline, and than turned back into crystal, that is, it has always stayed as a solid chunk, where the constituents (atoms, molecules) were always chemically bonded. Crystallization to me means something like converting a liquid to a crystal. Never heard this term used for crystal growth from gas (which makes the vast field of CVD, PVD processes and is should be covered in "crystal growth"). It may also be different from recrystallization in mobility of species (liquid vs. amorphous or polycrystalline solid). Physics is very different in what I outlined above. Off course, it is a narrow view, those processes often overlap, and the terms are used and misused in different ways. Materialscientist (talk) 11:34, 7 October 2009 (UTC)

I've thought for quite a long time that these articles should be brought together, but I haven't had the will power to do it.

I agree that they are long-standing/well established, but (in my view) that alone is not enough, it is only indicative that these articles are separate topics. In my view they are only long standing because they require quite a bit of effort to bring them together – a large energy barrier if you will.

I’m normally of the view that articles should not be merged, but I think, these two (/three) topics and just slightly different manifestations of the same subject matter with editors slightly focusing in on different aspects they find interesting. I think the subject matter of the articles would be better if all these different overlapping aspects were brought together in a single coherent way.

That is, start with outline of what crystalization is, then move onto the physical process of crystal growth i.e. the mechanics of how crystalization occurs, and then move onto recrystallization (chemistry), i.e. a repeating of the process of crystalization.

Perhaps I should have a go in a sandbox, to see if it is even feasible. -- Quantockgoblin (talk) 10:49, 7 October 2009 (UTC)

If as a result of merging you could rewrite those articles, it would be wonderful and I would help is necessary. All those articles need rewriting anyway. Materialscientist (talk) 11:34, 7 October 2009 (UTC)

Finally, I originally proposed merging much more that these three topics (see above). Merger might not be the way to go for all these topics. However, I think we should look to the distillation article as a good model of how the crystalization topic should be handled as the main umbrella topic. That is, like distillation there should be a main topic covering all aspects of the topic well, with links to sub-topics which have more detail. At the moment the main topic does not give good broad coverage and does not link to the sub-topics well.

these articles must not be merged. they may reference one another, but they are separate subjects:

• chemistry crystallization: separation of a mixture due to the different solluabilities of solutions
• chemistry crystal growth: the development and growth of crystals

122.104.39.87 (talk) 11:49, 21 April 2010 (UTC)

What about Water and Steel?

The article says that crystalization requires a supersaturated solution.

But crystalization doesn't require a solution at all. If you freeze (nearly) pure water at the correct rate, it crystalizes. If you cool red-hot steel at the correct rate, it develops a crystaline structure. In fact, a lot of crystals are formed from conditions other than supersaturated solutions.

Is there some other word for this, from a very technical perspective? Is some chemical engineer going to say "being crystaline or crystalization are two completely different things"? If so, then that should be clarified in this article, as well. And if not, then the article shouldn't say you must have a supersaturated solution to make crystals, only that it's ONE way to make them, and then should go on to talk about how and why crystals form when certain substances cool rapidly, et cetera.--Kaz 05:11, 17 July 2006 (UTC)

Water freezes at triple point. IMHO, the austenitic structure of steel, for example, is more related to freezing than to crystallization (aren't we talking of solid solutions?), and freezing is an equal-ranking unit process as crystallization is. However, I confess I am not so informed about metallurgy. Interesting question, though. --UbUb 14:14, 27 August 2006 (UTC)

The person that wrote the thing about supersaturation must have been a guy coming from solution crystallization, which is the predominant form of crystallization in the pharmaceutical industry, where high value products are produced. Of course melt crystallization (for example liquid steel) is also a type of crystallization. Water is also just a melt of ice, so this also belongs to the part of melt crystallization. All these processes have in common that a solid forms from a liquid or gas phase. The driving force of this is the difference of chemical potential between the two phases. —Preceding unsigned comment added by Necmon (talk • contribs) 16:02, 24 November 2009 (UTC)

Conceptual/didactic errors to correct?

1. "Crystallization is the (natural or artificial) process of formation of solid crystals from a homogeneous solution". Errors (?):
   1. the "homogeneous pre-condition" is understable only for Chemical's... here on wikipedia we only find that "a solution is a homogeneous mixture of one or more substances (the solutes) dissolved in another substance (the solvent)" on mixture. Need define homogeneous solution. If it is "only 1 solvent and 1 solutes" solution, it is a error. We can mix salt and sugar into the water and growth little salt crystals. Molecules find your similars. — Krauss 29 July 2006 (UTC).
   2. "Crystalization doesn't require a solution at all" (Kaz)... yes, not very didactic ... on engineer models we aproximate the concept of solution, "a solid/liquid mixture"... more didactic can be good. — Krauss 29 July 2006 (UTC).

wtf y merge?

Shouldn't it be more general, simply "formation of solid crystals from a non-crystalline phase"? That would include solutions, molten material, amorphous solids..., but exclude recrystallization in the metallurgical or geophysical sense. --Anastasius zwerg 10:00, 8 October 2007 (UTC)

Thermodynamic viewpoint

The article says:

«Textbook thermodynamics says that melting occurs because the entropy, S, gain in your system by spatial randomization of the molecules has overcome the enthalpy, H, loss due to breaking the crystal packing forces»

Is it exactly true? I think that a better explanation would be related with free energy, i.e. something like this:

«On the one hand, the crystal packing forces in the solid state yield a low enthalpy, H. On the other hand, the spatial randomization of the molecules in the liquid state yield a high entropy, S. But the physical transformations of a system are known to be guided by the minimization of its free energy, F=H-TS (where T is the temperature of this system). Thus, the lower the temperature is, the more the minimization of F relies on the minimization of H, that is, the more solid state is favorised. On the contrary, the higher the temperature is, the more the minimization of F relies on the maximization of S (hence the minimization of -TS), that is, the more the liquid state is favorised. It follows that, for some sharply defined temperature, the entropic factor overcomes the enthalpic factor: the crystal melts.»

88.183.11.75 (talk) 16:02, 10 December 2008 (UTC)

The current phrasing in this part is dubious and makes one think this part is copied form somewhere else. "Now put yourself in the place of a molecule within a pure and perfect crystal, being heated by an external source. At some sharply defined temperature..." This phrasing can be found almost identically in "Crystal Packing" by Angelo Gavezzotti and Howard Flack on an old site of the International Union of Crystallography, with copyright from 2005, older than the current article (but really is it?): source The same phrasing appears in "Bioseparation Engineering" by Ajay Kumar, Abhishek Awasth with a copyright from 2009 (newer or older than the Wikipedia passage?): source This makes one wonder what is the real source of the Wikipedia phrasing, whether it is one of the 2 above, or another one, or the above 2 copied from Wikipedia. This is not clear at all, we live in a complex world, but I know one thing: I don't want to put myself in the place of a molecule within a crystal, especially one that is going to be melted by heating. Ferred (talk) 11:49, 7 July 2016 (UTC)

Merge with Crystallization (engineering aspects)

This merger was proposed five years ago, but did not occur because it was argued that Crystallization (engineering aspects) was the technical version of Crystallization. Much has changed in the past five years with regards to how articles are organized and I believe the merger should be revisited. According to Wikipedia's policy on article title format, articles should "not use titles suggesting that one article forms part of another". The "(engineering aspects)" portion of the title does just that and demonstrates that these two articles discuss the same topic. For this reason and also because the relevance of crystallization to engineering is already discussed in Crystallization, Crystallization (engineering aspects) should be merged here. Neelix (talk) 21:35, 22 January 2011 (UTC)

Support: "Crystallization (engineering aspects)" is a bad lemma, and should be merged into Crystallization. Later, some very detailed sections could be exported into separate articles Cooling crystallization and Evaporative crystallization, with a short summary and a {{main|...}} link in crystallization. -- Marie Poise (talk) 08:37, 23 January 2011 (UTC)

Support per the nom. Wizard191 (talk) 19:09, 23 January 2011 (UTC)

Crystallization Process

I've posted an image that represent the artificial crystallization process. I hope that for you it's ok. — Preceding unsigned comment added by Elisavir (talk • contribs) 11:10, 2 December 2014 (UTC)

The image is hard to read and hard to understand for a non-specialist. The article is already overloaded with images. Materialscientist (talk) 11:13, 2 December 2014 (UTC)

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