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Topic: Sodium Sulfate / Table Salt Mixtures Questions  (Read 3079 times)

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Offline CLF3FTW

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Sodium Sulfate / Table Salt Mixtures Questions
« on: November 04, 2016, 10:23:49 PM »
I have read that a 1:1 (molar) mixture of sodium sulfate decahydrate and table salt has a melting point of 18 C, while the pure decahydrate has a melting point of 32 C. Does anyone know if having a lower ratio of table salt will cause the melting point to be somewhere in between 18 and 32 C, or if it will just make a mixture of the pure decahydrate and the decahydrate/table salt mixture? I have looked on Google for over an hour, but couldn't find anything. I have also tried to synthesize it from baking soda and Epsom salt (the reaction was listed on Wikipedia), but I couldn't drive the reaction to completion except for boiling, and I don't have the setup for a reflux.

Offline AWK

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Re: Sodium Sulfate / Table Salt Mixtures Questions
« Reply #1 on: November 05, 2016, 02:59:58 AM »
To obtain crystalline bloedite (Na2SO4·MgSO4·4H2O) dissolve both salts in molar ratio 0.4 Na2SO4 to 0.6 MgSO4 (calculated as anhydrous salts) and crystallize slowly by evaporation at temperature range 22-28 C.

http://www.phasediagram.dk/ternary/ternary2.htm

minor correction
« Last Edit: November 05, 2016, 04:36:04 AM by AWK »
AWK

Offline CLF3FTW

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Re: Sodium Sulfate / Table Salt Mixtures Questions
« Reply #2 on: November 05, 2016, 03:24:00 AM »
To obtain crystalline bloedite (Na2SO4·MgSO4·4H2O) dissolve both salts in molar ratio 0.4 Na2SO4 to 0.6 MgSO4 (calculated as anhydrous salts) and crystallize slowly by evaporation at temperature range 22-28 C.

http://www.phasediagram.dk/ternary/ternary2.htm

Are there any graphs like this but with sodium chloride instead of magnesium sulfate? This doesn't really relate to the question that I asked, but thank you for at least trying to help. Am I missing something obvious on the site that you linked?
« Last Edit: November 05, 2016, 04:33:13 AM by AWK »

Offline AWK

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Re: Sodium Sulfate / Table Salt Mixtures Questions
« Reply #3 on: November 05, 2016, 04:29:58 AM »
I do not know. The only known (for me) is a mixed salt that contain both NaCl and MgSO4 and also Na2SO4 (d'ansite 3NaCl·9Na2SO4·MgSO4).
But if you read about it in trustworthy source then you have a good starting point.
AWK

Offline Intanjir

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Re: Sodium Sulfate / Table Salt Mixtures Questions
« Reply #4 on: November 05, 2016, 02:19:28 PM »
Google for:
Phase Equilibria for the Pseudo-ternary System (NaCl + Na 2SO4 + H2O) of Coal Gasification Wastewater at T = (268.15 to 373.15) K

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