Olive bones to make cement
Spanish and Brazilian researchers have developed a new type of cement from olive bone ash and slag from blast furnaces, a more sustainable alternative to the cements currently used, being the first in the world manufactured only with waste. These researchers have started from the basis that the production, for example, of olive oil or stuffed olives generates a residue, which is bone, on which an energy assessment can be made, resulting in ash. Currently, olive bone is already used as a type of fuel or biomass for boilers.
Jordi Payá, researcher at the Institute of Science and Technology of Concrete (ICITECH) of the Universitat Politècnica de València (UPV), says that this new cement stands out especially for its "low carbon footprint" and its impact, in terms of greenhouse effect, "is much lower if compares with the cements currently used "in construction. In addition, according to the researcher of the UPV, this work opens a new business path for the use and energy recovery of a biomass, as is the case of olive bones, as well as waste from blast furnaces. Payá defends that the process for its manufacture is "very simple", since the residue of the combustion of the olive bones and slag is milled, the appropriate dose of both is established and everything is mixed with water.
In the tests carried out so far, the cement contained approximately twenty percent of olive stone ash and eighty percent of slag residues. The cement of alkaline activation manufactured by the researchers of the UPV and the Universidade Estadual Paulista also presents very good mechanical performance. Thus, it allows to obtain resistances sufficiently high for its application in construction (about 300 kilos per square centimeter to compression), especially in prefabricated.
Among its novelties, the researchers highlight the substitution of the chemical reagent of synthesis - of high price and with a significant carbon footprint - necessary in other alkaline activation cements investigated previously, by olive-stone ash. In addition, the preparation of these cements does not require high temperatures, as occurs with Portland cement, where temperatures are higher than 1,400 degrees Celsius, according to the researchers.
The development of this new product - at the laboratory scale - is the latest result of the work carried out by the research group in Chemistry of Building Materials of the ICITECH-UPV for almost ten years.
There is no doubt that the reuse of waste represents a very important environmental advantage in terms of C02 emissions. So much so that with this new construction material emissions can be reduced up to 20%, calculates the ICITECH. So far these Spanish and Brazilian researchers have managed to manufacture high performance mortars and concretes, with high enough resistance for their application in construction, especially for prefabricated.
