Banca de DEFESA: RODRIGO SOUZA PESSOA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : RODRIGO SOUZA PESSOA
DATE: 31/03/2021
TIME: 14:00
LOCAL: vídeo conferência
TITLE:

Phonolite and Verdete calcined at different temperatures as alternative sources of K and their interaction with limestone and coffee husk

KEY WORDS:

Minerals. Potassium. Rocks. Solubilization. Fonolito. Verdete

PAGES: 160
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SPECIALTY: Fertilidade do Solo e Adubação
SUMMARY:

PESSOA, Rodrigo Souza. Phonolite and Verdete calcined at different temperatures as alternative sources of K and their interaction with limestone and coffee husk 161f. Thesis (PhD in Agronomy, Soil Science). Institute of Agronomy, Department of Soils, Federal Rural University of Rio de Janeiro, Seropédica, RJ, 2020.

Brazil imports more than 90% of all the potassium it consumes in agriculture, currently the potassium fertilization of Brazilian soils is carried out using soluble salts such as potassium chloride. Due to the small national production, about 7.60% of the apparent high consumption, due to the fact that Brazilian soils are highly low in potassium, this demands a large consumption of these fertilizers, making Brazil a major importer of these potash fertilizers. This situation is aggravated by the only mine in operation in Brazil, located in the Taquari-Vassouras Complex, in Sergipe, with falling production registered by the Ministry of Mines and Energy, published in the Bulletin of the Mineral Sector (2019) of the years 2016 (316.4 103 t ), 2017 (306.2 103 t) and 2018 (201.2 103 t). It is worth mentioning that there is an expectation of extending the mine's useful life by another five years, with the revaluation of silvinite reserves and the execution of the Carnalita 800,000t projects and the Autazes Project 1,300,000 t, all in K₂O equivalent, with the execution of the projects mentioned the dependency would fall from 95% registered in 2014 to 60% in 2020, but due to the high costs, no project was executed (IBRAM, 2015). However, Brazil has large reserves of potassium silicate rocks of low solubility, with the potential to be used in agriculture as alternative sources of K, among these rocks we can mention the phonolite and verdigris both rocks found in the state of Minas Gerais, their extraction it is relatively inexpensive and the prospective volume of rocks is high. However, it is necessary to develop processing technologies capable of increasing the solubilization of these rocks to supply the demand for this nutrient in agriculture. Thus, the objective of this work was to carry out a chemical and mineralogical characterization of phonolite and verdigris, to evaluate the efficiency of techniques and physical treatments in the solubilization of potassium contained in rocks, to evaluate the K solubilized content of rocks mixed with two inorganic matrices calcitic and dolomitic limestone, enrich the rocks with K from an organic coffee husk matrix and an inorganic K₂CO₃ matrix in order to verify the behavior of the mixtures at different calcination temperatures. At the end of the laboratory tests, evaluate the dynamics of K release from fresh and calcined rocks at temperatures of 300, 600, 800 and 1000 ° C using water and 2% citric acid solution as extractor. At the end of laboratory tests, evaluate the best results in the release of the nutrient and apply the rocks as a source of K for the crops of aranua coffee, corn and beans in a greenhouse, evaluating their development and the production of biomass as a control source. Conventional K is KCl. For the characterization of the rocks, techniques such as X-ray diffractometry and chemical analyzes of high and low K extraction power were used. Heat treatments were carried out with different forms of calcination. After the analysis, in general it was found that phonolite is a rock of volcanic origin, composed mainly of microcline, orthoclasis, andesine and nepheline, distributed around the world and which presents about 9% of K₂O. The verdigris, in turn, is a metasedimentary rock composed of minerals from the micas, k-feldspars and quartz groups that can vary between 6 to 14% of K₂O. Its mineralogy is composed of 37% glauconite, 24% recrystallized quartz, 14% light brown clayey matrix; 11% kaolinite, 7% other micas, such as muscovite, chlorite and biotite. After the rocks are subjected to calcination which substantially alters the crystalline structure of the aforementioned minerals, providing an increase in the availability of K, the calcination of the rock plus fluxes with high calcium content, low magnesium content with an organic coffee husk matrix and K₂CO₃ at 300, 600, 800 and 1000 ° C, provided an increase in the potassium solubility when compared to the rocks in natura with emphasis on the temperature of 600 ° C for both rocks in all treatments. In general for the three evaluated cultures, the dry biomass production of the aerial part having the source of K rocks was satisfactory in comparison with the controls, except in the treatment of rocks mixed with dolomitic limestone at the highest temperatures of calcination evaluated in this study a fact that was verified in all cultures for both rocks. However, in general the treatment that obtained the highest biomass production was verified in the mixture of the rocks with the coffee husk in the treatment with the temperature of 600°C. The calcination temperatures had an influence both on the development of the plants and on the accumulated K content and amount for the three evaluated cultures.

BANKING MEMBERS:
Externo à Instituição - DOUGLAS RAMOS GUELFI SILVA - UFLA
Externo à Instituição - BRUNO DA SILVA MORETTI - UFLA
Presidente - 2213075 - EVERALDO ZONTA
Externo à Instituição - JOSE CARLOS POLIDORO - EMBRAPA
Externa à Instituição - TALITA DE SANTANA MATOS - UFRRJ