Cement production is a serious source of greenhouse gases that are responsible for global warming. However, around the globe cement production has not been given enough thought at for its impacts.

definition of cement

We often confound cement and concrete, using the terms interchangeably. What is cement? Cement usually comes in dry powder form, which when mixed with water undergoes a chemical reaction and becomes a strong binding agent. It can be used to make mortar to hold bricks and stones together, or mixed with crushed stone, gravel, or sand to create concrete.

Concrete is used for making infrastructure like sidewalks, road surfaces, foundations, buildings, dams, reservoirs, and bridges. It is also used for smaller home projects like fence footings, below-ground pools, even kitchen counter tops. Enormous volumes of concrete are mixed every year, all over the globe, putting high demands on cement production.

Cement Production

To produce cement, calcium carbonate must be heated to high temperatures to produce lime (CaO).

As part of that chemical reaction, the greenhouse gas carbon dioxide (CO₂) is released to the atmosphere. Lime is then further refined to produce cement powder. The calcium carbonate-to-lime chemical reaction accounts for 50% of CO₂ emissions associated with cement. Another 40% of emissions come from burning the fuel used to achieve the high temperatures needed, and the remaining 10% is emitted during the grinding and transportation phases. Due to the large amounts of carbon dioxide produced in the manufacturing of cement, and the vast amounts of concrete mixed worldwide every year (>3.4 billion tons), the cement industry is responsible for 5% of all greenhouse gas emissions.

Cement Demand in Uganda

In Uganda the demand for cement has scaled up, this is due to various needs that require use of cement for example the housing needs for the growing population. More cement has been acquired recently for the different projects of road constructions going on in various parts of the country the demand for cement to construct the Owen falls dam in 1952  arose the need to incorporate the Uganda cement industry. Other activities in Uganda that have used high amounts of cement include bridges, hydro projects, concrete application, constructing pavements. All these require large amounts of cement. Due to the high demand various cement factories are coming up leading to air pollution, clearing vegetation which have various advance effects onto the environment and emissions causing global warming.

New plants are being opened up but the government does not take keen interest in the mitigation measures that are to be taken by the cement factories. It is always after people that stay around the factories complaining and then the issue is considered vital. For example Hima Cement installed a $3.2m (sh8b) bag filter technology to trap cement dust at Kasese plant after public outcry that the company was polluting the air.  Hima cement produces up to 830,000 metric tonnes of cement annually after a $108m (sh270b) upgrade in the year 2010 and 2011.

What Can Be Done?

According to Dr. Beaudry. He states that since the need for concrete is not likely to abate soon, can the CO₂ emissions coming from cement manufacturing be reduced? Newer cement plans are designed to improve efficiency in the production process, and cleaner-burning alternatives to coal can be used as fuel sources. However, climate change mitigation through greenhouse gas emission reductions seem to be most feasible by reducing our total needs for production of cement. To do that, higher strength concretes are developed, volume-saving molds are used, and different cement compositions are tested. One promising avenue is the use of fly ash in concrete mixtures. Fly ash is one of the byproducts originating from combustion of coal, and when integrated in the concrete production process it can reduce the amount of cement needed in the mix. Fly ash can also be used to produce cement at much lower temperatures than when using conventional ingredients, reducing the amount of heating fuel needed, thus reducing greenhouse gas emissions.  

As well in construction of houses, the use of interlocking blocks would reduce on the amount of cement used during the construction since these blocks do not need cement to be compacted for building.

Environmental impact assessments should be taken as very important before factories come up in a given jurisdiction.

source

 http://environment.about.com/od/globalwarming/fl/Cement-and-Global-Warming.htm?utm_campaign=atlsocialposting_undefined&utm_medium=social&utm_source=facebook&utm_content=1447847586455