فنون

الجمال والعناية

حِرَف

الثقافة والتاريخ

ترفيه

البيئة

الطعام والمشروبات

الهندسة العكسية

العلوم

رياضة

التقنية

الأجهزة القابلة للارتداء

Glycerin from Candle-Works Sweet Water: Cap's Process

Unknown (museum object via DPLA) · Public domain

أنشأه

Charlie

13. أكتوبر 2026

Glycerin from Candle-Works Sweet Water: Cap's Process

The sweet water washed out of lime soap in the stearin candle works holds the fat's glycerin, with lime and fatty traces. Cap's process, given in Muspratt's Chemistry (1860), turns it into glycerin: the lime is thrown down as sulfate with sulfuric acid, the liquor is boiled down out of contact with the air, neutralised with chalk, filtered, cleared with bone black and concentrated to a colourless syrup of about 51° Twaddell.

متقدم

Several days

التعليمات

Boil down the sweet water

Reduce the glycerin water drawn off from the lime soap by evaporation over a fire.

المواد لهذه الخطوة:

ماء الغليسرول1 as required

فحم قاري1 as required

الأدوات المطلوبة:

حوض التبخير

فرن من الطوب

Find how much lime it holds

Measure out a known volume, precipitate its lime with oxalate of ammonia, collect the precipitate, dry it, burn it and weigh it. From that, work out how much sulfuric acid will just combine with all the lime.

الأدوات المطلوبة:

أكسالات الأمونيوم

ورق ترشيح

بوتقة من طين حراري

ميزان ذو كفّتين

Throw the lime down with sulfuric acid

Add that amount of sulfuric acid. Sulfate of lime falls. Let it settle and decant the clear liquid into another vessel.

المواد لهذه الخطوة:

حمض الكبريتيك1 as required

الأدوات المطلوبة:

حوض خشبي كبير

نظارة واقية من رذاذ الكيماويات

قفازات مطاطية

Boil it out of contact with air, to 14° Twaddell

Boil the liquid in a covered vessel, kept stirred, so the air cannot reach it. The boiling drives off volatile fatty impurities and the liquid loses colour and smell. At 14° Twaddell let it cool: more sulfate of lime falls.

المواد لهذه الخطوة:

فحم قاري1 as required

الأدوات المطلوبة:

حوض خشبي كبير

مجداف خشبي

فرن من الطوب

مقياس كثافة

Neutralise any excess acid with chalk

Test with litmus. If the liquid is acid, add powdered chalk or limestone a little at a time until it is neutral.

المواد لهذه الخطوة:

كربونات الكالسيوم - حجر جيري مجروش1 as required

الأدوات المطلوبة:

ورق عبّاد الشمس

مجداف خشبي

Boil on to 37.5° and filter

Boil again out of contact with air, stirring actively, to 37.5° Twaddell. Collect the sulfate and carbonate of lime on a filter.

المواد لهذه الخطوة:

فحم قاري1 as required

الأدوات المطلوبة:

حوض خشبي كبير

مجداف خشبي

فرن من الطوب

مقياس كثافة

مصفاة

Reduce to 49°, filtering again if needed

Evaporate the filtrate, keeping it well agitated, until on cooling it marks 49° Twaddell. If more sulfate of lime falls, filter again.

المواد لهذه الخطوة:

فحم قاري1 as required

الأدوات المطلوبة:

حوض التبخير

فرن من الطوب

مقياس كثافة

مصفاة

Clear it through bone black

Pass it through washed animal charcoal (bone black) to take out the tinge. It comes through as a colourless solution of about 45° Twaddell.

الأدوات المطلوبة:

أسود العظم

مصفاة

Concentrate to 51° Twaddell

Concentrate it carefully, driving off about a quarter of its weight of water, until the syrupy liquid reads 51.2° Twaddell. Store it closed.

المواد لهذه الخطوة:

فحم قاري1 as required

الأدوات المطلوبة:

حوض التبخير

فرن من الطوب

مقياس كثافة

Cap's readings as specific gravity

جارٍ تحميل دفتر Jupyter…

Troubleshooting

Glycerin troubleshooting.

Flow

History and honest limits

Muspratt (1860) gives Cap's process alongside the older lead-plaster method (olive oil and litharge, the lead removed with hydrogen sulfide). He quotes Wilson that Cap's glycerin, though better than the old product, is not absolutely pure. Bone black is used here as a filter that clears the colour; it is not part of the glycerin. The Twaddell-to-specific-gravity conversion is the standard definition of the scale.