Editing Turpentine (section)

==Converting crude turpentine to oil of turpentine==
{{see also|Rosin#Purification}}
[[Crude turpentine]] collected from the trees may be evaporated by [[steam distillation]] in a [[copper]] still. Molten [[rosin]] remains in the still bottoms after turpentine has been distilled out.<ref name="k71">Kent p.571</ref> Such turpentine is called '''gum turpentine'''.<ref>{{Cite web |title=Turpentine |url=https://www.britannica.com/topic/turpentine |access-date=2022-05-16 |website=Encyclopedia Britannica}}</ref> The term ''gum turpentine'' may also refer to crude turpentine, which may cause some confusion.

Turpentine may alternatively be extracted from [[destructive distillation]] of pine wood,<ref name="k69" /> such as shredded pine stumps, roots, and slash, using the light end of the heavy [[naphtha]] fraction (boiling between {{convert|90|and|115|°C|disp=or|round=5}}) from a crude [[oil refinery]]. Such turpentine is called '''wood turpentine'''. Multi-stage counter-current [[solid phase extraction|extraction]] is commonly used so fresh naphtha first contacts wood leached in previous stages and naphtha laden with turpentine from previous stages contacts fresh wood before [[vacuum distillation]] to recover naphtha from the turpentine. Leached wood is steamed for additional naphtha recovery prior to burning for [[energy recovery]].<ref>Kent pp.571&572</ref>

=== Sulfate turpentine ===
When producing chemical [[wood pulp]] from [[pine]]s or other [[coniferous trees]], sulfate turpentine may be condensed from the gas generated in [[Kraft process]] pulp [[Kraft process#Cooking|digesters]]. The average yield of crude sulfate turpentine is 5–10&nbsp;kg/t pulp.<ref name="sten">{{cite book |editor1-first= Per |editor1-last= Stenius |title= Forest Products Chemistry|series= Papermaking Science and Technology |volume= 3|year= 2000|publisher=Fapet Oy : Published in cooperation with the Finnish Paper Engineers' Association and [[TAPPI]] |location= Finland |isbn=952-5216-03-9 |pages= 73–76 |chapter= 2 }}</ref> Unless burned at the mill for energy production, sulfate turpentine may require additional treatment measures to remove traces of [[sulfur]] compounds.<ref>Kent p.572</ref>