Lye: Difference between revisions
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Lye is a caustic base, either sodium hydroxide (soda lye) or potassium hydroxide (potash lye). It's most commonly used for making [[soap]] by mixing lye with | Lye is the common name of a caustic hydroxide base, either sodium hydroxide (soda lye) or potassium hydroxide (potash lye). It's most commonly used for making [[soap]] by mixing lye with fats, but can also be used to cure and tenderize foods in small amounts. Sodium hydroxide may additionally be used in the production of paper, and water treatment. | ||
== Production == | |||
Potash lye is generally easier to produce using primitive methods than soda lye, as [[potash]] (K<sub>2</sub>CO<sub>3</sub>) is much easier to procure than [[Soda Ash|soda ash]] (Na<sub>2</sub>CO<sub>3</sub>), the latter of which requires the use of the ash from certain coastal plants, whereas former merely needs wood ash. | |||
The general procedure is as follows, first prepare a solution of slaked lime by adding quicklime to water, 2 parts by weight of quicklime for potash, 1 part by weight for soda ash. Do this slowly as the reaction is very exothermic. Next, simply add your carbonate of choice into the solution, either 5 parts by weight of potash or 2 parts by weight of soda lime. Then the solution can be carefully boiled down in a non-metallic container (a solution of hot lye will easily eat through most metals, and will easily eat through flesh), leaving relatively pure lye. This can be recrystallized if higher purity is needed. | |||
Two reactions have occurred in this process. First, the slaking of quicklime to produce slaked lime: | |||
CaO + H<sub>2</sub>O → Ca(OH)<sub>2</sub> | |||
Then, the double displacement of the carbonate with the slaked lime to produce lye and limestone: | |||
K<sub>2</sub>CO<sub>3</sub> + Ca(OH)<sub>2</sub> → 2 KOH + CaCO<sub>3</sub> | |||
or, | |||
Na<sub>2</sub>CO<sub>3</sub> + Ca(OH)<sub>2</sub> → 2 NaOH + CaCO<sub>3</sub> | |||
== Uses == | == Uses == | ||
Lye is a powerful base, particularly useful in the production of [[ | Lye is a powerful base, particularly useful in the production of [[soap]]. Soda lye in particular may also be used in the production of [[paper]] from wood, via soda pulping. | ||
== Dependencies == | == Dependencies == | ||
Revision as of 10:11, 8 May 2025
Lye is the common name of a caustic hydroxide base, either sodium hydroxide (soda lye) or potassium hydroxide (potash lye). It's most commonly used for making soap by mixing lye with fats, but can also be used to cure and tenderize foods in small amounts. Sodium hydroxide may additionally be used in the production of paper, and water treatment.
Production
Potash lye is generally easier to produce using primitive methods than soda lye, as potash (K2CO3) is much easier to procure than soda ash (Na2CO3), the latter of which requires the use of the ash from certain coastal plants, whereas former merely needs wood ash.
The general procedure is as follows, first prepare a solution of slaked lime by adding quicklime to water, 2 parts by weight of quicklime for potash, 1 part by weight for soda ash. Do this slowly as the reaction is very exothermic. Next, simply add your carbonate of choice into the solution, either 5 parts by weight of potash or 2 parts by weight of soda lime. Then the solution can be carefully boiled down in a non-metallic container (a solution of hot lye will easily eat through most metals, and will easily eat through flesh), leaving relatively pure lye. This can be recrystallized if higher purity is needed.
Two reactions have occurred in this process. First, the slaking of quicklime to produce slaked lime:
CaO + H2O → Ca(OH)2
Then, the double displacement of the carbonate with the slaked lime to produce lye and limestone:
K2CO3 + Ca(OH)2 → 2 KOH + CaCO3
or,
Na2CO3 + Ca(OH)2 → 2 NaOH + CaCO3
Uses
Lye is a powerful base, particularly useful in the production of soap. Soda lye in particular may also be used in the production of paper from wood, via soda pulping.
Dependencies
- Lye