Fluoride aided potassium extraction from Verdete rock by thermal processing with ferrous sulfate heptahydrate. / Extração de potássio auxiliada por flúor da rocha de Verdete por processamento térmico com sulfato ferroso hepta-hidratado

Authors

  • Antônio Clareti Pereira
  • Emily Mayer de Andrade Becheleni
  • Marta Ribeiro dos Santos Gomes
  • Sônia Denise Ferreira Rocha

DOI:

https://doi.org/10.34115/basr.v3i2.1565

Keywords:

fertilizer, potassium, fluoride, glauconite, ferrous sulfate.

Abstract

Glauconite is a green-colored monoclinic mineral with hydrated phyllosilicate of potassium and iron. It has low resistance to weathering and is usually found in sandstones and shales, as well as in marls and impure limestones. It is a secondary mineral formed from the modification of iron-rich micas, such as biotite. Even though it is an alternative source of potassium, it is still not extracted commercially on a large scale due to the lack of commercial technology that makes the business viable economically.Ferrous sulfate heptahydrate is a residue or by-product formed during the pickling of iron and steel and also in the manufacture of titanium dioxide from the ilmenite.Iron, as a raw material for the production of reagents, is abundant in the tailings of this metal.The use of ferrous sulfate as a sulfating agent has the advantage of being more selective and less aggressive during processing, in addition to the property of being thermosensitive.Fluorine accelerates this sulfation process due to an ionic substitution action on the structure of glauconite and on compounds that prevent the reaction, such as calcium sulfate.This work has investigated the release of potassium by dissolution in a 2% (w/w)citric acid solution in water, after previous thermal and chemical processing of glauconite rock (10% K2O) from Cedro doAbaeté - MG - Brazil with ferrous sulfate heptahydrate and NaF in the ratio (1.00: 0.70: 0.01), respectively.Potassium soluble in citric acid and not soluble in water characterizes a slow acting fertilizer.Thermal processing was performed at temperatures of 500°C and 700°C for 6h in a fluidized bed oven.The selection of ferrous sulphate was based on a thermodynamic evaluation of the system.The results showed that the thermal processing of the rock and ferrous sulfate mixture alone was not effective for the release of potassium in aqueous solution and in citric acid.The extraction of potassium from raw rock in citric acid was 7%.The mixture of rock and ferrous sulfate, without fluoride, in citric acid had an extraction rate of 6.8%.However, the same mixture with addition of 29ppm of fluorine had different results, in water (20% at 700°C) and mainly in citric acid (52.1% at 700°C), increasing the availability of potassium in more than 7 times when compared to the availability of rock potassium in natura.This study confirms that the combined effects of fluorine and temperature of thermal processing increase the release of potassium from glauconite.

References

Martins, E. S. et al. Agrominerais: rochas silicáticas como fontes minerais alternativas de potássio para a agricultura. In: Adão, B. L.; Lins, F. (Eds.). Rochas e minerais industriais: usos e especificações. Rio de Janeiro, Cetem, 2010. p.205-221.

Srasra, E.; Trabelsi-Ayedi, M. Textural properties of activated glauconite. Applied Clay Science, Amsterdam, v. 17, n. 2, p. 71-84, July 2000.

Eichler, V. Disponibilidade do potássio do verdete de Abaeté calcinado com e sem calcário magnesiano, para a cultura do milho em solos de textura média e argilosa. Lavras, 1983. 147 p. Dissertação (Mestrado em Ciências do Solo) – Escola Superior de Agricultura de Lavras.

Marschner, H. Mineral nutrition of higher plants. London, Academic Press, 1995. 889p.

Tokunaga, Y. Potassium silicate: a slow-release potassium fertilizer. Kaihatsu Hiryo Co.2-1-13. 1991.

Vallareli. J.V. Ardósias Verdete de Cedro do Abaeté na Produção de Termofosfato Potássico Fundido e sua Eficiência Agronômica. Anais da Academia Brasileira de Ciências, v. 31, p. 363-375, 1993.

Piza, P.A.T, Bertolino, L.C., Silva, A.A.S., Sampaio, J.A., Luz, A.B. Verdete da região de Cedro do Abaeté (MG) como fonte alternativa para potássio. Geociências, 30:345-356, 2011.

Orioli Junior, V., Coutinho, E.L.M. “Effectiviness of Fused Magnesium Potassium Phosphate for Marandu Grass”, Revista Brasileira de Ciência do Solo, v. 33 pp. 1855-1862, 2009.

Mangrich, A., Tessaro, L., Dos Anjos, A., Wypych, F., Soares, J. A slow-release K+ fertilizer from residues of the Brazilian oil-shale industry: synthesis of kalsilite-type structures. Environmental geology, v.40 n.8 p.1030-1036, 2001.

Lopes, A.S.; Freire, J.C.; Aquino, L.H., Felipe, M.P. (1972) Contribuição ao estudo da rocha potássica - Verdete de Abaeté (Glauconita) para fins agrícolas. Agros, 2:3242.

Faquin, V. (1982) Efeito do tratamento térmico do sienito nefelínico adicionado de calcário dolomítico, na disponibilidade de potássio ao milho (Zea mays L.), em casa de vegetação. Dissertação (Mestrado) - Escola Superior de Agricultura Luiz de Queiroz, Piracicaba. 115p.

Leite, P.C. (1985) Efeitos de tratamentos térmicos em misturas de verdete de Abaeté, fosfato de Araxá e calcário magnesiano, na disponibilidade de potássio e fósforo. Dissertação (Mestrado) - Escola Superior de Agricultura de Lavras, Lavras. 146p.

Silva, A.A.S.; Sampaio, J.A.; Luz, A.B.; França, S.C.A; Ronconi, C.M. Modelagem de liberação controlada de potássio a partir flogopita em solução: explorar a viabilidade da utilização de rock flogopitito moido como uma fonte de potássio alternativa em solo brasileiro. Journal of the Brazilian Chemical Society. v.24, n.8, p.1366-1372, 2013.

Mazumder, A.K., Sharma, T., Rao, T.C. Extraction of potassium from glauconitic sandstone by the roast-leach method. International Journal of Mineral Processing, v.38, p.111–123, 1993.

Jena, S.K., Dhawan, N., Rao, D.S., Misra, P.K., Mishra, B.K., Das, B. Studies on extraction of potassium values from nepheline syenite. International Journal of Mineral Processing. v.133, p.13–22. 2014.

Swamy, M.S.R., Prasad, T.P. Kinetics of the thermal decomposition of Fe III sulphates heptahydrate in air. Thermochimica Acta, n.62 (1983), p.229-236.

Petkova, V., Pelovski,Y. Investigation on the thermal properties of Fe2O(SO4)2. Journal of Thermal Analysis and Calorimetry, Vol. 64 (2001) 1025–1035.

Petkova, V., Pelovski,Y., Paneva, D., Mitov, I. Influence of gas media on the thermal decomposition of second valence iron sulphates. J Therm Anal Calorim (2011) 105:793–803.Navarro, J.M.F. El Vidrio. Colección Textos Universitarios, no 6, Madri

Published

2019-03-22

How to Cite

Pereira, A. C., Becheleni, E. M. de A., Gomes, M. R. dos S., & Rocha, S. D. F. (2019). Fluoride aided potassium extraction from Verdete rock by thermal processing with ferrous sulfate heptahydrate. / Extração de potássio auxiliada por flúor da rocha de Verdete por processamento térmico com sulfato ferroso hepta-hidratado. Brazilian Applied Science Review, 3(2), 1373–1384. https://doi.org/10.34115/basr.v3i2.1565

Issue

Section

Original articles