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- v. Simple past tense and past participle of underburn.
Sorry, no etymologies found.
· Traditional lime burning in intermittent kilns waste a great deal of fuel (usually firewood) and often produce non-uniform, low quality limes (overburnt or underburnt).
A large proportion of overburnt and underburnt material can be expected (around 25 % of each).
- The quicklime lumps became progressively darker from underburnt to overburnt.
Another problem was the large amount of underburnt material comprising a considerable proportion of unburnt core.
If firing is conducted correctly there should be no, or a very little, underburnt stone, but this should also be checked for.
When a clamp has been burnt its contents are found to have been unequally fired, and are part of them underburnt, part well burnt, part overburnt.
It, however, is not in the condition of hard, heavy clinkers, such as are produced in the ordinary cement kiln, which require special machinery for breaking up into smaller pieces before being admitted between the millstones for the final process of grinding; nor does it consist of an overburnt exterior and an underburnt core or center portion; but it issues from the cylindrical furnace in a condition resembling in appearance coarse gunpowder, with occasional agglutinations of small friable particles readily reduced to fine powder in an ordinary mill, requiring but small power to work, and producing but little wear and tear upon the millstones.