8. Kalkugn

(Lime kiln)

There was once a lime kiln here. Limestone was burned in the kiln to produce quicklime (unslaked lime). The kiln was in use during the 1800s. It was round with a diameter of roughly 6 metres, and had an opening of 2-3 metres facing southeast. There is a connection between the lime kiln and the quarry at Sillavadsån. The limestone was probably transported to the kiln. In order to transform limestone into quicklime, the carbon dioxide has to be removed from the stone. This process begins when the temperature exceeds 800 degrees. In the bottom of the kiln there were two channels containing wood, above which shale and limestone were arranged in lay- ers. The wood was lit and burned continuously for 2-3 days. After three days, less than 1% carbon dioxide remained in the quicklime. No more wood was added, and the fire went out. The kiln was then left to cool down for a day, after which the lime was taken out. It had lost nearly half its weight and was now white. In order to be able to use the unslaked lime for mortar or whitewash, it had to slaked. This was done by mixing the unslaked lime with water.

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