Limestone is made of the chemical calcium carbonate and was formed by compression of the shells of dead sea creatures at the bottom of clear, tropical seas over millennia.
It is an excellent building stone, but if heated to a temperature of 600°C it changes to calcium oxide (quick lime), and by mixing this with various other materials and heating, it can be converted into all manner of other useful chemicals.
If you put water on quicklime, much heat is produced and it changes to slaked lime which is an alkali.
Plants grow better in slightly alkaline soil, so spreading slaked lime on fields improves soil fertility.
Cement powder is made by kilning finely crushed limestone with shale and grinding the result to a fine powder.
Other products include lime mortar (quicklime and sand), bleaching powder (Made from quicklime and a chlorine compound like common salt – sodium chloride), washing soda (sodium carbonate made from limestone and common salt), soap (made from fats and alkalis) and glass (made by heating alkalis and sand to a high temperature).
When industrialisation began to grow at the end of the eighteenth century, demand for such products increased dramatically. Need for most of these products continues unabated to the present day.
Production of most of these products became concentrated in the Widnes-Runcorn area in North West England. The juxta position of all the necessary raw materials can explain this perfectly. There are huge deposits of very pure limestone in Derbyshire. There are unlimited deposits of common salt under the Cheshire Plain. The Lancashire Coalfield (around Wigan) provided coal for powering furnaces. The canals were developed to transport raw materials and finished goods.
- There are many cement factories around Buxton in the limestone area of the Peak District.
- Pilkingtons at St Helens is one of the largest glass manufacturers in the world.
- There is a very large sodium carbonate plant near Northwich. (wich = salt deposit).
- Lever Brothers started as a soap manufacturer at Port Sunlight on the Wirral bank of the Mersey Estuary.