2 Cited claim. Spelling. Removed distraction about Apple Jack.
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In some sense it is true, if you consider alcohol harmfull substance. For example applejack can be created by this process (but the ice is thrown away and what remains is the final product) applejack - wikipedia

Joking aside,Wikipedia explains that this can be used as desalinationtechnique of fractional freezing - wikipedia can be used for desalination:

Fractional freezing can be used to desalinate sea water. In a process that naturally occurs with sea ice, frozen salt water, when partially melted, leaves behind ice that is of a much lower salt content. Because sodium chloride lowers the melting point of water, the salt in sea water tends to be forced out of pure water while freezing. Likewise, the frozen water with the highest concentration of salt melts first. Either method decreases the salinity of the frozen water left over, and with multiple runs can be drinkable.

I would not rellyrely on it to remove arbitrary toxic chemicals from water, but in. In survival situation (with accesaccess to freezing and energy to melt things and prevent yourself from freezing) it could be worth doing to puriffypurify water, but. I cannot compare it to alternatives.

In some sense it is true, if you consider alcohol harmfull substance. For example applejack can be created by this process (but the ice is thrown away and what remains is the final product) applejack - wikipedia

Joking aside, this can be used as desalination fractional freezing - wikipedia

I would not relly on it to remove arbitrary toxic chemicals from water, but in survival situation (with acces to freezing and energy to melt things and prevent yourself from freezing) it could be worth doing to puriffy water, but I cannot compare it to alternatives.

Wikipedia explains that this technique of fractional freezing can be used for desalination:

Fractional freezing can be used to desalinate sea water. In a process that naturally occurs with sea ice, frozen salt water, when partially melted, leaves behind ice that is of a much lower salt content. Because sodium chloride lowers the melting point of water, the salt in sea water tends to be forced out of pure water while freezing. Likewise, the frozen water with the highest concentration of salt melts first. Either method decreases the salinity of the frozen water left over, and with multiple runs can be drinkable.

I would not rely on it to remove arbitrary toxic chemicals from water. In survival situation (with access to freezing and energy to melt things and prevent yourself from freezing) it could be worth doing to purify water. I cannot compare it to alternatives.

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source | link

In some sense it is true, if you consider alcohol harmfull substance. For example applejack can be created by this process (but the ice is thrown away and what remains is the final product) applejack - wikipedia

Joking aside, this can be used as desalination fractional freezing - wikipedia

I would not relly on it to remove arbitrary toxic chemicals from water, but in survival situation (with acces to freezing and energy to melt things and prevent yourself from freezing) it could be worth doing to puriffy water, but I cannot compare it to alternatives.