Food grade lye vs technical lye
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I don't think the soap knows any difference. Your pickles and pretzels and lutefisk might though.
I've used both and can say that they both make great soap without any detectable differences that I ever noticed.
IrishLass
IrishLass
cleanwater
Well-Known Member
I'd be curious about contaminants, though as a chemist I'm not actually sure which kind would be purer...
cheesenoodle
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cleanwater said:
Food grade lye has tighter restrictions on things like heavy metals such as lead than technical grade does. That's why I'd be worried about using tech grade..
falldowngobump
Well-Known Member
I've used both, with no differences at all. I use tech grade all the time now. If there are differences no one could tell, including me.
cleanwater said:
There are three methods that commerical lye is made through eletrolosis of salts
Mercury cell process (also called the Castner-Kellner process); sodium ions are reduced to sodium metal, which forms an amalgam with a mercury cathode; this sodium is then reacted with water to produce NaOH. There have been concerns about mercury releases, although modern plants claim to be safe in this regard.[5] Does leave mercury traces
Diaphragm cell process; uses a steel cathode, and the reaction of NaOH with Cl2 is prevented using a porous diaphragm, often made of asbestos fibers. In the diaphragm cell process the anode area is separated from the cathode area by a permeable diaphragm. The brine is introduced into the anode compartment and flows through the diaphragm into the cathode compartment. A diluted caustic brine leaves the cell. The sodium hydroxide must usually be concentrated to 50% and the salt removed. This is done using an evaporative process with about three tonnes of steam per tonne of sodium hydroxide. The salt separated from the caustic brine can be used to saturate diluted brine. The chlorine contains oxygen and is purified by liquefaction and evaporation.[6][7] asbestos has been known to be cancer causing
Membrane cell process; similar to the diaphragm cell process, with a Nafion membrane to separate the cathode and anode reactions. Only sodium ions and a little water pass through the membrane. It produces a higher quality of NaOH. Of the three processes, the membrane cell process requires the lowest consumption of electric energy and the amount of steam needed for concentration of the caustic is relatively small (less than one tonne per tonne of sodium hydroxide).[6][8]
It is obvious only one is abcent of dangerious levels of toxins. The membrane cell process.
The first using mercury has been the blame of high levels of mercury in frutose sugar which uses caustic soda in its making.
You would think in these times of awareness that the third and most safe methods of collecting lyes ,membrane cell method from salts would be the perfered way. But from my studies so far. Only 13% of the lye supplies, both sodium and potassium hydroxcide ,are made using this method. Due to the expense of factory equipment needed to upgrade to this safer method.
soapbuddy
Well-Known Member
NaOH is not the same as KOH. I buy whichever lye costs less.
soapbuddy said:
Not according to this website
http://chemindustry.ru/Potassium_Hydroxide.php
Production.
Almost commercial potassium hydroxide is manufactured by electrolysis of aqueous solution of potassium chloride KCl or potassium carbonate K2CO3:
2KCl + 2H2O → 2KOH + Cl2↑ + H2↑
There are three technological processes most commonly used for KCl electrolysis:
Mercury cell electrolysis. Titanium anodes are located above a liquid mercury cathode in the electrolysis bath with a solution of potassium chloride. When an electrical current is applied, chlorine is released at the titanium anodes and metal potassium dissolves into the mercury cathode forming an amalgam. Dissolved potassium is then reacted with water releasing hydrogen to produce KOH. There have been concerns about mercury releases, although modern technologies claim to be safe in this regard. This method consumes vast amounts of energy.
Diaphragm cell method. In this route a porous asbestos or polymer diaphragm is deposited on an iron grid cathode preventing the chlorine forming at the anode and the potassium hydroxide forming at the cathode from re-mixing. The potassium hydroxide must usually be concentrated and the salt excess removed. This is done using an evaporative process. Potassium hydroxide produced by this method is contaminated with potassium chloride;
Membrane cell method. - similar to the diaphragm cell process. The electrolysis cell is divided into two by a ion exchange membrane. Only potassium ions and a little water molecules pass through the membrane. This method is nearly as efficient as the diaphragm cell and produces very pure potassium hydroxide but requires very pure potassium chloride solution. Of the three processes, the membrane cell process requires the lowest consumption of electric energy and the amount of steam needed for concentration of the end product
This one shows how sodium hydroxcide is made
http://www.ausetute.com.au/chloralkali.html
has more basic detail
NaOH is used for making solid or hard soap, and KOH is used for making soft soap.
IrishLass
IrishLass
carebear said:
Well basically in reference to the concern about the differences between food grade and industrial lye's ,and their purposed safety. What I discovered above, is yes not all lye is created equal. And viewing the different methods of processing commercial lye's from salts. It is obvious the concern should center around how the lye was made. The membrane cell method would be my pick.
To my knowledge, asbestos is only dangerous when inhaled (or ingested). I don't have any problems with asbestos in soap.
I assume it's not very difficult tracking down the purchased lye back to the producer, and finding out the manufacturing method.
I assume it's not very difficult tracking down the purchased lye back to the producer, and finding out the manufacturing method.
Fragola said:
Yeah the easiest way would be to discover the manufacture that makes it with the method you approve, and ask who thier distributors are. That is how I trace anything I am looking for. I always tend to go to the head of the source. Knowing tinkle down info can be tainted. Everyone wants to make a buck. Cant blame them.
soapbuddy
Well-Known Member
Exactly.carebear said:
Annavlz
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I bought some caustic soda online, dont know what kind of it, it was packed into a small (1kg bottle ) for me with only one lable "sodium hydroxide". I used it with no problems, never had a zap while testing sope the next day after making.
Then I bought some in a big bucket and as trice as cheaper at the cash&carry shop, with a lot of words about safety and uses and a number >98%. Every batch I did since is a total disaster: if I dont put it in the fridge it is overheated and leaking with lye, if I stop gelling it is ok but has zap for 2 days already.
I use my usual recipes, I checked the amount of lye in different calcs.
The last batch I made I overfat it 10% but it still zaps very very strong.
So what can be wrong? And what can I do with it?
Then I bought some in a big bucket and as trice as cheaper at the cash&carry shop, with a lot of words about safety and uses and a number >98%. Every batch I did since is a total disaster: if I dont put it in the fridge it is overheated and leaking with lye, if I stop gelling it is ok but has zap for 2 days already.
I use my usual recipes, I checked the amount of lye in different calcs.
The last batch I made I overfat it 10% but it still zaps very very strong.
So what can be wrong? And what can I do with it?
