Natural lime and environmental impact

After biomattone and rice cement we go back to talking about building materials and we do it with lime. That of lime is an industry with high energy consumption, just think that 50% of the production costs oflimethey are attributable to energy expenditure.

As well as the costs, also the environmental impact of lime is mainly linked to its production: to obtain the quicklime pure limestone must reach a temperature of about 800 ° and then be "off " with an abundant water bath; this is how the lime putty,a material described as "sustainable" because it has a very long life cycle and can be disposed of easily when compared to other building materials; however, even if the lime it is defined as a sustainable material and slaked lime is presented as a natural material, there is no shortage of considerable environmental costs.

Some companies, to market a "product as natural as possible“, They age the lime putty directly in the open air. This is the case of the Trieste-based company Harpo group which places the lime putty in a humid environment, storing it in open-air holes to ensure natural aging. With this methodology, the grassello di lime it is aged for at least 24 months; in this period the lime assumes a uniform shade and an almost velvety texture. By applying a lime of this kind it is possible to obtain an effect antiqued and, at the same time, permeable to vapor, shiny and extremely resistant over time.

Even if we talk about "ecological lime"We remind you that the production process requires large amounts of energy that weigh heavily on the environment unless the manufacturing company uses particular strategies to lower the impact. Always taking the Trieste company as an example, we see that the lime used in the manufacture of its products from the Sandtex line, it is obtained by cooking river pebbles made up of calcium carbonates and magnesium.

These pebbles are placed in a traditional furnace powered by wood sawdust; thanks to the natural cooking and aging method, environmental costs can be reduced. The kiln reaches temperatures of 900-1000 ° C and finishes the lime firing within a week.

With the furnace, electricity costs are reduced but not water costs: cooking is obtained quicklime which is extinguished in the traditional way with excess water usually placed in a lime extinguisher machine, the finished product is given by magnesian slaked lime.

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