Cement Production Releases More Carbon Dioxide Than You Think

1 day ago

Forget about the newly opened refinery of Aliko Dangote who is the richest black man on earth, let's talk about his cement factory which made him a billionaire at first. It looks like this guy likes to deal in CO₂ emitting type of businesses and he has made a lot of money emitting this greenhouse gas into our atmosphere. I know you will ask me how has he done so, or how does cement release CO₂ into the atmosphere.

Cement is the ingredient that binds concrete together and it is being used for a lot of things related to construction but this binding substance is not eco friendly as one ton of cement would produces about 0.8 to 0.9 tons of CO₂emissions which is about 8% of the world's anthropogenic CO₂ emissions yearly. Before you start to think that the CO₂ is as a result of burning fossil fuel to produce it, actually the chemistry of cement produces CO₂.

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If you are going to purchase cement, there is a high chance you are buying portland cement because it is the main type of cement used around the world. I remembered asking my grandfather at some point what the meaning of portland cement was and he told me it was because it was made from portland and then laughed and said he didn't know but he was going to ask around.

It is referred to as portland cement because it is produced by combining limestone and clay and passing it through extreme heat and Clinkers are formed which cement manufacturers then add other substances like gypsum which then gives us our final product. When we are looking at the carbon production from cement, it is found in the clinker as the heating of the limestone breaks the calcium carbonate into calcium oxide and carbon dioxide. Adding the clay is what adds silicon dioxide to the calcium oxide to produce clinker.

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So when clinker is produce, it releases CO₂ and 1kg of clicker will produce about half its amount in CO₂. While it releases Co₂ into the atmosphere, when it is mixed with water, CO₂ from the air reacts with calcium oxide to make calcium carbonate. Also, when cement starts to age, it begins to absorb small amount of CO₂ but while cement sucks CO₂ after it has been produced, what it absorbs isn't breaking even to what it emits during production. A study that was carried out between 1930 and 2013 showed that materials made from cement only absorbed about 43% of the carbon that was emitted during production.

With this information, it will be better to start looking at more viable ways to produce cements while emitting less carbon dioxide and this is where a company called solidia comes in. They create cement with less limestone to clay, and they heat it at a lesser temperature compared to portland cement and these reduces the amount of CO₂ being emitted. Unlike portland cement where you need to mix with water and let to solidify over a period of days in a process known as curing, with solidia's cement, CO₂ is needed to solidify their concrete and with this, they need to get carbon dioxide from somewhere else to make their concrete harden and it does so in 24 hours.