Showing posts with label quicklime. Show all posts
Showing posts with label quicklime. Show all posts

Tuesday, 12 April 2011

Marsden Lime Kilns (NZ405645)

 
© Copyright Mick Garratt and licensed for reuse under this Creative Commons Licence.
   
Marsden Limekilns, facing bleakly out to sea at the southern extremity of Marsden Bay, are one of only three Scheduled Ancient Monuments in the Borough of South Tyneside, the other two being Arbeia Roman Fort and St.Paul’s Monastery. They are unmissable to anyone using the present-day A183 Coast Road.

The massive creations date from the 1870s, being an off-shoot industry of the nearby (but long gone) Whitburn Colliery. The limestone which was processed in the kilns was quarried literally yards away on the clifftop above, the stone being fed into the top of the complex. Coal from the nearby pit fuelled the kilns, heating and breaking down the stone to produce quicklime, which was used to neutralise soil, and also had uses in the cement, steel and chemical industries. The kilns to the right pre-date the circular affairs to the left, the latter being added in 1895. The insertion of the raw material at the top and the extraction of the quicklime at the base was almost continuous when the kilns were operating full-pelt. A railway line at the front took the goods to South Shields for shipping.

When the colliery closed in 1968 the limekilns went with them, their source of power gone.




Friday, 30 July 2010

Lime Kilns? (various locations – Beadnell’s at NU237285)

Many of you will have noticed large man-made, cave-like structures dotted around the British countryside, and perhaps even be aware that they are lime kilns. Maybe a teacher or a relative pointed this out to you years ago – information which you have sagaciously passed on to the next generation, of course. But did your teacher/parent/mentor – and, in turn, your good self – really know what was meant when some adult show-off uttered unconvincingly “Well, they’re, er … lime kilns, aren’t they. For making, erm, lime.”?

Well, lime – or, rather, quicklime – is indeed produced inside a lime kiln. And it is achieved, basically, by the heating of limestone to 900-1,000°C, at which temperature the stone ‘calcinates’, or breaks down. Carbon dioxide is given off, leaving calcium oxide – or quicklime. In other words:
CaCO3 + heat = CaO + CO2
or,
Limestone + heat = quicklime + carbon dioxide

Quicklime is really useful stuff, and can be used in mortar/plaster, paper/glass/steel production, sewerage treatment, etc., but is especially handy in agriculture (to counter acidic soils) and to hide the smell of decomposition in open graves (plague outbreaks, and the like). Curiously, before electric lighting came along it was used in theatres as an illuminant – as it glows brightly when heated to high temperatures (hence ‘limelight’). Anyway, historically, at least, there was quite a demand for the stuff.

The thing is, quicklime is rather unstable. Left to its own devices it will react naturally with carbon dioxide in the atmosphere and revert to its ‘natural’ limestone state. Transportation, therefore, is/was a problem – as was easily lumping about the limestone, and, indeed, the coal needed to heat the kilns themselves. So, this is why you find so many lime kilns near the coast: easy to get the limestone/coal in, and easy to get the quicklime out. So quayside spots like those at Seahouses and Beadnell were perfect. Improvements in the transportation network during the nineteenth century led to many more inland (and often much larger) sites being developed.

So the next time your little sidekick asks the question, you know exactly what to say. And, moreover, you’ll know precisely what you’re talking about.

Beadnell Lime Kilns
(by Tom Curtis)