Brazilian researchers have developed an ecological fertilizer based on eggshells as an alternative to chemical fertilizers. The technique uses mechanochemical milling in which materials are transformed through thermal energy and friction.
The project was developed at the Laboratory of Chemistry of Advanced Materials (Laqma) of Federal University of Paraná (UFPR) in partnership with Roger Borges, researcher at Embrapa Instrumentação.
According to the university, almost 6 million tonnes of eggshells are produced worldwide annually. Brazilian egg production alone reached 45.6 billion eggs in 2021. As a consequence, the model could create value to egg farmers.
“We use waste, such as eggshells, which are rich in calcium, or asbestos, which is a toxic waste,” said one of the researchers.
With a deep understanding of eggshell chemical components, researchers were able to produce the fertilizer that would not harm the environment and can be useful for agriculture at the same time.
Brazil and many countries are currently facing a crisis in the supply of fertilizers due to the conflict between Russia and Ukraine, which are 2 of the world’s main suppliers.
In 2021, Brazilian imports of fertilizers totalled 41.5 million tonnes and a total value of US$15.2 billion, which is an increase of 20% compared to 2020.
“The main composition of both asbestos and eggshells is calcium carbonate (CaCO3). We are developing the product with the aim of selling it on the market,” explained Borges.
Eggshells are placed in a high-energy ball mill. The components react and generate new compounds capable of providing phosphorus, calcium and potassium, which are 3 essential minerals for the development of crops.
Industrial production plans to mix eggshells with other elements, such as asbestos. According to him, the fertilizer generated does not represent any danger and, therefore, the researchers have applied the product to the National Institute of Industrial Property (Inpi).
The main economy is improving raw materials usage because fewer minerals are used to ensure the same agricultural productivity, in addition to environmental advantages.
Borges added that another advantage is the economy of elements such as limestone, which is rich in calcium, because the reserves of these materials are finite. In 2020, Brazilian crops used more than 45,000 tonnes of agricultural limestone, much of it resulting from the exploitation of the country’s reserves.