Technology helps finding new sources of fertilizers for Brazilian agriculture

22 de October de 2014

Researchers from the UFV Department of Soils are pioneers in the use of synchrotron light technology in geoscience studies. Specifically, they are searching new ways for the production of fertilizers, also aiming to better understand the dynamics and destination of nutrients and toxic elements in the environment and the biogeochemical processes occurring in remote areas, such as Antarctica. The research is being conducted at the Laboratório Nacional de Luz Síncrotron (National Synchrotron Light Laboratory) (LNLS), in Campinas (SP), Brazil, and has already brought results for the production of fertilizers from alternative mineral sources.

The UFV Study Group on Fertilizers, named GeFert, has also been successful in the search for viable alternatives for the production of phosphorus (P) and potassium (K), which, together with nitrogen (N), form the the main chemical compound of mineral fertilizer formulas used for increasing production, NPK. This research is relevant because Brazil is extremely dependent on the import of mineral fertilizers.

It is known worldwide that Brazilian economy is driven by agriculture. Thanks to the use of fertilizers it is now possible to grow important commodity crops in the Cerrado, or Brazilian savanna, to secure exports and economic growth. However, Brazil is a big importer of fertlizers to produce food, fiber and biofuels. We purchase 90% of the potassium and 55% of the phosphorus used in agricultural fertilizers in the country. This demand tends to increase 3% per year just to maintain the current agricultural production. Brazilian consumption is expected to exceed 200 million tons in 2015. This has been pushing the main agriculture producer countries to seek ways to reduce the dependence on the fertilizer producing counterparts, which control the prices of the products according to their convenience and can become a threat to food security in case of international conflict or boycott to the marketing of these minerals.

 In search of alternative sources

 In countries with major deposits of phosphorus and potassium, it is easy to remove them from the mines where they were sedimented in rocks during the evolution of the planet. However, GeFert researchers are studying other minerals containing these chemicals, in order to find alternatives to increase production and reduce the dependence on imported products. “We’ll never have sources as abundant as those of these countries, but we have alternatives in Brazil. However, it is not enough to discover such sources. It is necessary to find efficient means to remove the elements from minerals at costs that will not throttle production”, says Professor Leonardus Vergütz, a member of GeFert.

Professor Edson Mattielo, another member of the group, explains that some sources of these nutrients are even abundant in Brazil, but their low solubility and poor agronomic efficiency prevent them from being used. This was the case of verdete, a rock rich in potassium, abundant in central Minas Gerais. However, compared to traditional deposits, verdete contains low concetrations of potassium, which is closely attached to chemical structures and cannot be easily released. This increases the cost of extraction. Therefore, the researchers are studying thermal treatments with the addition of different fluxing agents and microorganisms capable of solubilizing  the mineral and producing potassic fertilizers.

These surveys involve partnerships with the UFV departments of Microbiology and Plant Pathology. The results obtained by GeFert are promising and may generate new patents for Brazil and decrease the dependence on international sources. “The research will be fundamental for the development of new technologies for the production of fertilizers from economically and environmentally viable alternative sources,” says Professor Edson Mattiello.

Synchrotron Light

Besides production issues, technologies for fertilizer use have not evolved much over the last 30 years. Therefore, the GeFert members have also dedicated to understand better the molecular structures of the main components of these fertilizers. From a single rock, for example, it is possible to extract different proportions of chlorides, silicates and other chemical compounds, all of them generally classified by industries only as potassium.

With the technology available, it was impossible to perform the precise identification of each compound. Then, the UFV researchers established a partnership with the Laboratório Nacional de Luz Síncrotron – LNLS (National Synchrotron Light Laboratory), whose technology can be used to determine precisely the chemical species of each element present in the rock and the chemical environment where it is found.

All monitoring of the changes occurring during the different treatments applied to the verdete, for example, was possible due to the use of advanced spectroscopic techniques available at LNLS. In a single sample of potassium fertilizer, they identified the formation of different proportions of silicate and potassium chloride. Chlorides are the potassium salts most used in fertilizers. However, silicates are noble and more expensive materials that can be applied in the pharmaceutical and ceramics industry.

The development of a process to separate these two elements could make it economically viable to extract potassium from verdete, even at low concentrations. The team are trying to understand the mechanisms and interactions that occur at tiny scales, since these data can generate amazing results for national agribusiness. “Although such work may seem a very basic science, with no practical application, it is only through the knowledge generated by this research that new technologies can be proposed and tested,” explains Professor Vergütz.

Besides the Soil Fertility group, other professors from the UFV Department of Soils have  developed studies at LNLS related to carbon sequestration in soil organic matter, availability and destination of toxic elements and rare earth metals in the environment, as well as the characterization and formation process of Antarctic soils. Professors Leônidas Carrijo de Azevedo Melo, Ivo Ribeiro da Silva, Roberto Ferreira de Novais, Nairam Félix de Barros, Liovando Marciano da Costa, Jaime Wilson Vargas de Mello, Reinaldo Cantarutti, Maurício Paulo Ferreira Fontes and Carlos Ernesto Gonçalves Reynaud Schaefer are among the participants in these research works.