Crude Glycerol: Candle-Works Sweet Water Neutralised and Steam-Concentrated to 28° Bé (Thorpe, 1912)

'Saponification crude' or 'candle crude' glycerin, the best grade of crude glycerin: the sweet water from autoclave saponification, holding 6 to 16 per cent of glycerol, is neutralised, filtered and boiled down by steam until it holds 85 to 90 per cent glycerol (sp. gr. 1.240 to 1.242, sold as 28° Bé). It is yellow to dark brown and sweet, with up to 0.3 per cent ash, mostly calcium, magnesium or zinc sulphate. Refined with charcoal it gives 'refined' glycerin. Unknown: what the metallic oxides in the sweet water are neutralised with. Thorpe does not say. Source: T. E. Thorpe, Dictionary of Applied Chemistry vol. II (1912), pp. 762-763. Picture: Fig. 1, a Wetzel pan.

中级

Unknown

说明

Neutralise and filter the sweet water

Take the sweet water of the autoclave process (6 to 16 per cent glycerol). Neutralise the metallic oxides it contains and filter it. Unknown: the neutralising agent; Thorpe does not give it.

此步骤所需材料：

甘油水1 6-16 % glycerol

未知材料1 neutralising agent, not given

所需工具：

压滤机

Concentrate by steam

Boil the filtered solution down by steam, in a Wetzel pan or in a vacuum evaporator, until it holds about 85-90 per cent glycerol, sp. gr. 1.240 to 1.242 (28° Bé). Ours: a steam-heated evaporating pan, checked with a hydrometer.

所需工具：