Disputing the notion that materials are 'boring'
On annual visits to Scotland, driving just north of the border along the A74(M), I always slow down at the sign to the Scottish Museum of Lead Mining, but then resolve to visit it on the next trip. Alas, I have missed my chance – I have read in the Guardian that the museum is to close.
What is equally disappointing is that one of the newspaper’s columnists, Jon Henley, has declared it Britain’s most boring museum! Has he ever visited it, I wondered? I am tired of the arrogance and ignorance of arty-crafty journalists when they comment on technological matters.
Descriptions of materials as 'boring'
I am reminded how upset I was some time ago when another writer selected ‘Corrosion of Plywood’ as the world’s most dreary newspaper headline. I doubt that he actually read the piece – plywood is in fact a fascinating and useful material, and its durability is certainly a suitable subject for academic study.
I have recently stumbled upon yet another example of what I like to call ‘an abuse of materials’ in George Monbiot’s otherwise excellent book, Heat: How to stop the planet burning. In the penultimate chapter, he covers carbon dioxide emissions during the production of cement, but he prefaces his review with the following, ‘I have learned from bitter experience that it is not easy to interest people in cement.’ Why ever not? – considering its importance, complexity and diverse properties.
Cement manufacture and its detrimental effect on the environment
The starting point in cement manufacture is the reduction of limestone (calcium carbonate) to lime (calcium oxide), with a simultaneous generation of carbon dioxide. This process, known as calcination, creates about 500kg of carbon dioxide per metric tonne of cement.
If one adds to this the gas emitted during quarrying, transporting, grinding and subsequent heating, it transpires that one tonne of cement produces one tonne of carbon dioxide. Building a house requires about five tonnes of cement, thus generating an equal amount of carbon dioxide. Globally, cement production and use is believed to be responsible for between 5-10% of total carbon dioxide emissions, so there is a considerable incentive to find an alternative ‘cement’.
A cement substitute
The most promising substitute is a material similar to the pozzolan cements that were based on a volcanic ash and were used by the Romans to construct, for example, the wonderful and still perfect Pantheon in Rome. The new/old substances are known as geopolymeric cements. They are stronger than ordinary cements, and are more durable and dimensionally stable. Their use will reduce the production of carbon dioxide by 80-90%.
In spite of all these exciting revelations, Monbiot concludes his chapter with, ‘Re-reading this section, I am forced to admit that cement is in fact a rather dull subject. I beg your forbearance…’. All I can say is that if Monbiot finds cements uninspiring, he must lead an extraordinarily stimulating and eventful life. In any event, he has written a fascinating book and, speaking more generally, it is good to see the environment is given the attention it deserves.
Do scientists ever dismiss as ‘boring’ important technical issues? Of course they do. It was, after all, an Oxford chemistry graduate who in 1982, in the aftermath of the Falklands War, exclaimed, ‘It is exciting to have a real crisis on your hands, when you have spent half your political life dealing with humdrum issues like the environment.’ I hope someone has told Baroness Thatcher that the environment is now not in the least ‘humdrum’.
Jon Henley's diary, The Guardian, 24 October 2006